Autosteroscopic 3D/2D switchable colour image display apparatus

<u style="single">Field of the invention</u>

The invention relates to a method for the spatial representation of a scene / an object, in which a plurality of individual picture elements α_ij is made visible simultaneously in a grid of columns i and rows j, the pixels α_ij Part information from multiple views A_k (k = 1 ... n) of the scene / object and where adjacent picture elements α_ij Emitting light of different wavelengths λ or wavelength ranges Δλ. The invention further relates to arrangements for carrying out the method.

<u style="single">State of the art</u>

As a result of the efforts to visualize objects, landscapes, insights into the interior of bodies and other things on the basis of images spatially perceptible to a viewer, in the course of development, a large number of autostereoscopic methods have arisen, which are roughly described in lenticular methods, Distinguish prism scanning method and barrier method.

This method is based on the principle of visually reproducing several different perspective views at the same time, but by means of suitable measures only making one or more of these perspective views visible to each observer's eye, thereby creating a parallactic effect that allows the viewer spatial perception.

As is known, in these methods or When using arrangements that operate according to these methods, as an unwanted by-product pseudoscopic effects that have the consequence that the viewer sees a respect to the spatial depth inverse and thus unrealistic image. Also arise depending on the design of related arrangements more or less noticeable the commonly referred to as moire fringes. Although the above phenomena can be reduced or excluded, which usually requires additional measures by which the arrangements are more expensive or adversely affected in terms of their usability.

It is known to use electronically controllable displays for optical reproduction of the perspective views of an object for the purpose of autostereoscopic display, which displays are also suitable for the two-dimensional representation of views when actuated in the conventional manner. In this regard, it is desirable for conceivable applications, switching from the spatial autostereoscopic into a two-dimensional representation (and vice versa) of the same scene or to be able to carry out the same object. Disadvantageously, however, changes in the known arrangements of this type with the switching the image quality so that, for example, displayed text is good in one mode, but only insufficiently readable in the other. This occurs in arrangements according to the barrier method, especially when the barrier consists of vertically juxtaposed, alternately opaque and transparent strips. Moiré effects also occur here and make for an unpleasant visual sensation. Even lenticules reduce the readability of displayed text by the permanent optical image significantly.

In EP 0791847 an arrangement is described in which autostereoscopic images are generated using a conventional RGB LC display in conjunction with oblique lenticulars, resulting in principle moire patterns. In order to reduce the moiré pattern, it is proposed in this publication to arrange the color filters associated with the subpixels in a different configuration. Disadvantageously, to implement this proposal, a changing intervention in proven embodiments and manufacturing processes is required, which would be associated with too much effort in view of the industrial mass production of the usual RGB LC displays. In addition, the effect of the proposed measure does not extend to the elimination of the disadvantages in the case of two-dimensional representations, so that a consistently high image quality when switching a representation of autostereoscopic on two-dimensional is not guaranteed. The above-mentioned document is an arrangement in which lenses are used to produce the autosteroscopic display.

In WO 97/02709, too, a change in the areal structure of an image display device is proposed in order to achieve a reduction of the moiré effect. In this case, the RGB pixel surface structure is to be changed so that there is a moireverminded autostereoscopic effect. The barrier method is used by using transparent slits surrounded by opaque surfaces.

US Pat. No. 5,936,774 uses structured light sources as the basis for the autostereoscopic display, inter alia also be structured with respect to their spectral properties used. These cooperate with lens-like optical components which, for each perspective view, image a group of light concentrations generated at specific intervals onto intended regions of light modulators, for example LC displays. Even with these arrangements, the adverse effects already described occur.

In JP 10333090 it is proposed to use a colored illumination and color filters to select the direction of the light emanating from the perspective views. In addition, an optical filter is provided which is intended to reduce the amount of light in predetermined wavelength ranges. The procedure described here is a two-channel method, based on only two perspective views, one of which is offered to one eye of the observer for perception. The width of a filter element or According to the disclosure, the width of a lighting element is approximately twice the width of a subpixel in an LC display. It follows inevitably that conventional LC displays for generating the structured illumination are not applicable, since these displays a RGBRGBRGB ... color structure of the subpixels is given. In addition, the periodically arranged and strip-shaped color filter inevitably lead here again to the emergence of moiré strips. Another disadvantage is the fixed predetermined distance of the viewer from the image plane, which varies with the specified equations or Functions results.

The publication US Pat. No. 5,751,479 describes an autostereoscopic display in which wedge-shaped light propagation directions are predetermined with vertically extended strip-shaped red, green and blue filters for the views, which are likewise nested in one another in a strip-like manner. The viewer thus sees with each eye an image composed of vertical stripes. The arrangement always gives a viewer who moves his eyes in the vertical direction to the image surface, always the same views, ie in such a movement, the perceived perspective impression always remains the same.

A disadvantage of this arrangement is that the viewer must remain in a viewing position. Furthermore, the number of possible views to be displayed is limited due to the geometric conditions to a maximum of four views, whereby the maximum number of viewers is relatively small. Much of the design options is suitable for only one observer. Moreover, even with the slightest maladjustment of the color filters against the image generator, strong moiré effects occur.

Also in JP 10186272 and JP 8194190 are for autostereoscopic display color LC displays in conjunction with colored lights or Color filters used. In the arrangements proposed here, the autostereoscopic display can be based on several perspective views. For the filters, only the primary colors red, green and blue are provided; the illumination sources and the upstream filters are strictly periodically structured in the same or opposite order of primary colors on the associated color mask. The color filters are strip-shaped, and the width of the filter elements substantially corresponds to the product of the width of a subpixel and the number of views shown.

It follows that the width of a filter element must be at least twice as large as that of a subpixel in the LC display. Thus (as with the arrangement according to JP 10333090), the use of commercial LC displays for structured illumination is not possible due to the given RGBRGBRGB ... subpixel structure. Furthermore, moire fringes are generated to a great extent when, for example, eight perspective views of the autostereoscopic view of a scene or of an object. Then namely a strip-shaped RGB sequence of a filter, assuming an extent of 70 .mu.m, as currently customary for a subpixel, would have a width of 3 × 8 × 70 μm = 1.68 mm on the LC display. Such a structure creates moire fringes, which reduces the quality of the display.

JP 8163605 again describes an arrangement in which two perspective views are used. The pixels on which the views are displayed, in each case clearly visible only for one of the two eyes of the viewer. To select the direction of the light emanating from the pixels strip-shaped color filter in front of a display or arranged in front of a strip-shaped RGB lighting element. Again, the disadvantages occur, as already described above.

As described in JP 8146347, for purposes of directional selection, a separate transparent opaque barrier with a color filter corresponds. The transparent areas of the barrier or the translucent areas of the color filter are either slot-shaped or circular. Here, as well as in the arrangement according to JP 8146346, which uses a two-channel method with strip-shaped, vertical color filters for the directional assignment of the two perspective views, also the disadvantages described occur.

EP-A-0 744 872 discloses a two-channel stereoscopic viewing method based on two perspective views of an object or scene. In this case, the image information from both perspective views are made visible separately and exclusively for the right or the left eye of only a single observer. Are more than a pair of such perspective views available, the object or represent the scene from different viewing positions, they are always offered in pairs consecutively for viewing, so that the change from pair to pair, the viewing is always possible stereoscopically, but from different corresponding viewing positions. In this case, according to EP-A-0 744 872, a synchronization between the image reproduction and the structured barrier, which is designed to generate two stereoscopic views, is provided.

In EP-A-0 860 728 an autostereoscopic display is described, which is also suitable for use in two-channel display methods. At the same time, only image information from two perspective views is always visible at the same time, one of which is assigned to the right eye and the other to the left eye of a viewer. The technical solution which continues to be described there in detail serves to point the observer to viewing areas in which a pseudoscopic perception is possible.

<u style="single">Description of the invention</u>

Based on this prior art, the invention has the object, with a few, preferably commercially available optical assemblies to achieve an autostereoscopic display simultaneously for a variety of viewers with improved visibility.

According to the invention in a method of the type described above for the α of the pixels_ij emitted light propagation directions, which are dependent on the wavelength of this light, wherein the propagation directions within a viewing space in which the / the viewer reside, in a plurality of intersections, each corresponding to a viewing position intersect. From every viewing position, a viewer with one eye predominantly takes picture elements α_ij a first selection and with the other eye predominantly picture elements α_ij a second selection from the views A_k (k = 1 ... n) true.

A picture element α_ij be in this context a self-luminous or illuminated area of ​​small size with an area of ​​about 10,000 microns² up to a few mm²on which a minimal section of one of the views A_k (k = 1 ... n), in the following as partial information of such a view A_k (k = 1 ... n) can be represented at the point i, j. Advantageously, with the index pair i, j and the position in the view A_k from which the partial information originating on the pixel α_ij is reproduced - as far as the views A_k (k = 1 ... n) are structured in rasters of columns i and rows j.

Under a selection from the views A_k (k = 1 ... n) are the views A_k to understand their picture elements α_ij either predominantly visible to one or the other eye. For example, the directions of propagation of light, that of pixels α_ij comes on which partial information of the views (corresponding to a first selection) A_k (k = 1 ... 4) are given, are specified so that this light or this partial information predominantly reach the left eye of a viewing viewer in the viewing space, while the propagation directions for the light, the pixels α_ij comes on which partial information of the remaining (corresponding to a second selection) views A_k (k = 5 ... n) are shown, are given so that this light or this partial information predominantly reach the right eye of the same observer. In this case, therefore, the first selection provided for the left eye comprises views A._one, A₂, A₃ and A_four, The second selection provided for the left eye would be views A_five, A₆ ... A_n include.

In this case, the cases are expressly included in the inventive method in which the of a pixel α_ij coming light is not complete, but only partially reaches the eye of the observer, which is exemplary in partial coverage of a pixel α_ij about by arrangement parts, is conceivable.

The condition that an eye "predominantly" pixels a_ij or on these picture elements a_ij reproduced reproduced sub-information is satisfied even if this eye, for example, 80% of the pixels a_ij sees the partial information of the view A_one while the other eye also has such pixels a_ij, the partial information of view A_one can see, but less than 80%.

The propagation directions are preferred by a plurality of wavelength filters β_why given, wherein each one pixel α_ij with several associated wavelength filter elements β_why or a wavelength filter element β_why with several associated picture elements α_ij corresponds in such a way that in each case the connecting line between the center of the area of ​​the visible portion of a picture element α_ij and the center of area of ​​the visible portion of a wavelength filter element β_why a propagation direction corresponds.

It is advantageous if the wavelength filter elements β_why arranged in arrays with columns p and rows q and one or more such arrays the grid with the pixels α_ij, relative to the viewing direction of a viewer, are at a fixed distance z forward and / or downstream.

For the purpose of specifying the propagation directions, the picture elements α_ij, the associated partial information of the views A_k (k = 1 ... n), exactly defined positions i, j assigned to the grid. The wavelength filters β_whyassociated with these picture elements α_ij are assigned, defined positions p, q are assigned to the array. The propagation directions then result from the positions of the picture elements α_ij on the grid and the positions of the corresponding wavelength filter elements β_why on the array in conjunction with the distance z between raster and array.

The assignment of partial information of the views A_k (k = 1 ... n) to picture elements α_ij as well as the positioning of these pixels α_ij On the grid can be made according to the invention according to the following function (F1) <maths id="math0001" num="(f1)"><math display="block"><mrow><mrow><mo>(</mo><mrow><mi mathvariant="normal">F</mi><mn>one</mn></mrow><mo>)</mo></mrow><mi> </mi><mi>k</mi><mo>=</mo><mi>i</mi><mo>-</mo><msub><mi>c</mi><mrow><mi>i</mi><mi>j</mi></mrow></msub><mo>⋅</mo><mi>j</mi><mo>-</mo><mi>n</mi><mo>⋅</mo><mi>IntegerPart</mi><mrow><mo>[</mo><mrow><mfrac><mrow><mi>i</mi><mo>-</mo><msub><mi>c</mi><mrow><mi>i</mi><mi>j</mi></mrow></msub><mo>⋅</mo><mi>j</mi><mo>-</mo><mn>one</mn></mrow><mi>n</mi></mfrac></mrow><mo>]</mo></mrow><mo>.</mo></mrow></math><img file="EP1689162A2_D0001.tif" /></maths> Hierin are designated with<ul id="ul0001" list-style="dash" compact="compact"><li>i is the index of a picture element α_ij in a row of the grid,</li><li>j is the index of a picture element α_ij in a column of the grid,</li><li>k is the consecutive number of the view A_k (k = 1 ... n), from which the partial information originates, which on a certain picture element α_ij should be reproduced</li><li>n the total number of views used A_k k(k= 1 ... n),</li><li>c_ij a selectable coefficient matrix for combining or mixing the different views A_k (k = 1 ... n) derived partial information on the grid and</li><li><i>IntegerPart</i> a function for generating the largest integer, which does not exceed the argument in square brackets.</li></ul>

In other words, the indices (i, j) denote the positions of pixels α_ijfor which it is necessary to specify which of the views A_k (k = 1 ... n) the part information to be displayed is to be obtained. Where i stands for the horizontal index (with values ​​ranging from 1 to horizontal pixel resolution, which is triple the value of pixel resolution when displaying sub-information on RGB subpixels) and j for the vertical index (with values ​​ranging from 1 to the value of vertical pixel resolution).

For any but fixed number n of views A_k (k = 1 ... n), all of which have the same image resolution or format, the partial information of the views A to be displayed on the grid_k (k = 1 ... n) are to be combined, the following must be considered for the combination rule:

The coefficient matrix c_ij can have as entries values ​​that correspond to real numbers. For i and j, natural numbers greater than "zero" are possible in the abovementioned value range.

The one shown on the grid, from the different partial information of the views A_k (k = 1 ... n) combined total image is generated according to the above-mentioned function given these parameters by all possible index pairs i, j are traversed.

As a further prerequisite for the generation of a spatial representation, it is determined according to the invention in which structure the wavelength filter elements β_why, which in cooperation with the picture elements α_ij specify the propagation directions to be positioned within the array with columns p and rows q.

The wavelength filter elements β_why have transparency wavelength or transparency wavelength ranges λ_b which preferably has the wavelength or the wavelength range λ_a of the corresponding picture elements α_ij corresponding to radiated light. For particular embodiments of the invention, which will be explained below, the wavelength filter elements β_why for example, also transparency wavelengths / wavelength ranges λ_b which are out of the spectrum of visible light so that the visible light passes through these wavelength filter elements β_why is blocked.

A transparency wavelength / a transparency wavelength range λ_b can also stand for a combination of different wavelength ranges (eg transparent for blue and red, not for green). Accordingly, the index b can have values ​​from 1 to the maximum number of the specified transparency wavelength / wavelength ranges λ_b to have. In the case of a wavelength filter array, which is intended to let light of the primary colors R, G, B pass at predetermined positions defined by the index pair p, q, while at other such positions the entire visible spectrum is to be blocked, b_max =. 4 In this case, for example, the transparency wavelengths / wavelength ranges λ correspond_one, λ₂ and λ₃ red (R), green (G) or blue (B) light, and the transparency wavelength / the transparency wavelength range λ_four is completely outside the spectral range of all visible light. Such a transparency wavelength / such a transparency wavelength range λ_four then yields an opaque filter (S).

The wavelength filter elements β_why on the array can be considered as translucent or transparent parts of a mask image. The position of each wavelength filter β_why is uniquely defined by the index p, q. Each wavelength filter element β_why becomes a certain transparency wavelength or a certain transparency wavelength range λ_t assigned. In this case, the structuring of the wavelength filter elements β takes place_why to a mask image - analogous to the combination of the partial information of the different views A_k (k = 1 ... n) to an overall picture - according to the following rule (F2): <maths id="math0002" num="(f2)"><math display="block"><mrow><mrow><mo>(</mo><mrow><mi mathvariant="normal">F</mi><mn>2</mn></mrow><mo>)</mo></mrow><mi> </mi><mi>b</mi><mo>=</mo><mi>p</mi><mo>-</mo><msub><mi>d</mi><mrow><mi>p</mi><mi>q</mi></mrow></msub><mo>⋅</mo><mi>q</mi><mo>-</mo><msub><mi>n</mi><mi>m</mi></msub><mo>⋅</mo><mi>IntegerPart</mi><mrow><mo>[</mo><mrow><mfrac><mrow><mi>p</mi><mo>-</mo><msub><mi>d</mi><mrow><mi>p</mi><mi>q</mi></mrow></msub><mo>⋅</mo><mi>q</mi><mo>-</mo><mn>one</mn></mrow><mrow><msub><mi>n</mi><mi>m</mi></msub></mrow></mfrac></mrow><mo>]</mo></mrow><mo>,</mo></mrow></math><img file="EP1689162A2_D0002.tif" /></maths> With<ul id="ul0002" list-style="dash" compact="compact"><li>p the index of a wavelength filter β_why in a row of the array,</li><li>q the index of a wavelength filter element β_why in a column of the array,</li><li>b is an integer corresponding to a wavelength filter element β_why at position p, q defines one of the provided transparency wavelengths / wavelength ranges λ and values ​​between 1 and b_max may have,</li><li>n_m an integer value greater than "zero", which preferably represents the total number n of views A represented in the combination image_k corresponds,</li><li>d_why a selectable mask coefficient matrix for varying the generation of a mask image and</li><li><i>lntegerpart</i> a function for generating the largest integer that does not exceed the argument in square brackets.</li></ul>

Preferable are embodiments of the invention, in which b_max and n_m are the same size.

The selectable coefficient matrix d_why can have as entries values ​​that correspond to real numbers. In this case, for p and q, which (as already described) describe positions within the wavelength filter array, natural numbers greater than "zero" are possible.

The generation of the combined overall image from the partial information of the views A_k (k = 1... n) and the generation of the mask image are therefore based on similar or at least closely related regulations. The wavelength filter elements β_why as elements of the mask image preferably have approximately the same surface area as the image elements α_ij.

The latter fact is particularly advantageous in connection with the reduction of moiré effects. Visible periodic overlays of the grid of picture elements α_ij for image reproduction with arrays of wavelength filters β_why as a mask image can be defined defined in this way, which also Moire effects are reduced.

The mere fact that each mask image is defined in a wavelength-selective manner can be exploited to significantly reduce moiré effects by suitably structured mask images. This happens, for example, when the wavelength filter elements β_why for the primary colors R, G, B are each arranged on a substantially opaque background pattern in the form of an isosceles triangle. For then, for each basic color R, G, B, it is not primarily a preferred direction of the superimposition with picture elements α lying directly underneath or above_ij Each of the same basic color in the plane of the array, but there are many different directions, whereby the perceptibility of Moire is significantly inhibited.

For different b, it is also possible to use transparency wavelengths / wavelength ranges λ_b be given the same content: for example, b_max= 8, λ_one bi λ₃ for R, G, B in this order and λ_four bis λ_eight for wavelengths outside the visible light, in which case λ_one bis λ₃ the colors R, G, B transmit and λ_four bis λ_eight block off the visible spectrum. Then the combination rule for the parameters d_why = -1 = const and n_m = 8 is a mask image that periodically creates oblique stripes in the RGB colors on an opaque background. In each case, five of the filter elements β remain between these colored stripes_why opaque in every line. The angle of inclination of the colored strips depends on the dimensions of the filter elements β_why.

In a further exemplary embodiment, in turn, several of the transparency wavelengths / wavelength ranges λ_b have the same filter effects: Let λ_one... λ₇ Wavelength ranges that block the entire visible spectrum, λ_eight a transparent spectrum for the visible spectrum and let n be_m= 8 and d_why= -1 = const, according to the rule for creating a mask image, a substantially opaque mask image is obtained, which contains evenly distributed oblique transparent stripes on the surface, occupying approximately one-eighth of the entire surface.

The wavelength filter elements β_why and the picture elements α_ij are therefore assigned to one another by wavelengths or wavelength ranges, ie a wavelength filter element β_why a certain transparency wavelength / wavelength range λ_b can each be the light of those pixels α_ij let pass that emit light that corresponds to this transparency wavelength or within the transparency wavelength range λ_b lies. But it can also, as already shown, be provided that wavelength filter elements β_why that of associated pixels α_ij block off incoming light.

The measured distance z between the array of wavelength filters β_why and the grid of pixels α_ij is a parameter taking into account the width of the picture elements α_ij, the width of the wavelength filter elements β_why and the size of the viewing space is set, in such a way that for a given combination of the individual sub-information of views A_k (k = 1... n) on the grid within the viewing area, the scene / object shown is perceivable three-dimensionally.

By way of example, the distance z between the array of wavelength filters β_why and the grid of pixels α_ij, measured in the direction of sight, are determined by the following equation (F3): <maths id="math0003" num="(f3)"><math display="block"><mrow><mrow><mo>(</mo><mrow><mi mathvariant="normal">F</mi><mn>3</mn></mrow><mo>)</mo></mrow><mi> </mi><mfrac><mi>with</mi><mrow><msub><mi>s</mi><mi>p</mi></msub></mrow></mfrac><mo>=</mo><mfrac><mrow><msub><mi>d</mi><mi>a</mi></msub></mrow><mrow><msub><mi>p</mi><mi>d</mi></msub></mrow></mfrac></mrow></math><img file="EP1689162A2_D0003.tif" /></maths> Hereby means:<ul id="ul0003" list-style="dash" compact="compact"><li>s_p the mean horizontal distance between two wavelength filters β_whyif the array with the wavelength filters β_why in the direction of a viewer behind the grid of pixels α_ij is arranged, or the average horizontal distance between two pixels α_ij if the grid of pixels α_ij in the direction of a viewer behind the array with the wavelength filters β_why is arranged</li><li>p_d the mean pupil distance in a viewer and</li><li>d_a a selectable viewing distance, which is essentially the average of all possible distances between the grid of picture elements α in the entire viewing area_ij and corresponds to a viewer or a viewing position.</li></ul>

In practice, other approaches to determine the distance z are possible. In general, the context also applies here: the larger z, the larger or more distant the viewing space is formed.

Now, for example, to generate a mask image with b_max = 4 three transparency wavelengths / wavelength ranges λ_one, λ₂, λ₃ given for R, G, B and another transparency wavelength range λ_fourwith which the visible light can be blocked completely, the result is the use of the coefficient matrix d_whywhich can be produced according to the rule (F4) <maths id="math0004" num="(f4)"><math display="block"><mrow><mrow><mo>(</mo><mrow><mi mathvariant="normal">F</mi><mn>four</mn></mrow><mo>)</mo></mrow><mi> </mi><msub><mi>d</mi><mrow><mi>p</mi><mi>q</mi></mrow></msub><mo>=</mo><mstyle scriptlevel="+1"><mfrac><mrow><mi>p</mi><mo>-</mo><mn>one</mn><mo>-</mo><mrow><mo>(</mo><mrow><mi>p</mi><mi mathvariant="normal">against</mi><mn>3</mn></mrow><mo>)</mo></mrow></mrow><mi>q</mi></mfrac></mstyle><mi>d</mi><mrow><mo>(</mo><mrow><mrow><mo>(</mo><mrow><mi>p</mi><mo>+</mo><mi>q</mi></mrow><mo>)</mo></mrow><mi mathvariant="normal">against</mi><mn>eight</mn></mrow><mo>)</mo></mrow><mo>+</mo><mrow><mo>(</mo><mrow><mstyle scriptlevel="+1"><mfrac><mrow><mi>p</mi><mo>-</mo><mn>four</mn></mrow><mi>q</mi></mfrac></mstyle></mrow><mo>)</mo></mrow><mi>d</mi><mrow><mo>[</mo><mrow><mi>d</mi><mrow><mo>(</mo><mrow><mrow><mo>(</mo><mrow><mi>p</mi><mo>+</mo><mi>q</mi></mrow><mo>)</mo></mrow><mi mathvariant="normal">against</mi><mn>eight</mn></mrow><mo>)</mo></mrow></mrow><mo>]</mo></mrow></mrow></math><img file="EP1689162A2_D0004.tif" /></maths> one for the spatial representation of an object / scene on the basis of n = 8 views A_k (k = 1 ... n) well suited mask image.

Here is n_m= 8; "mod" denotes the residual class with respect to a divider. The function δ returns the value "zero" for all arguments other than "zero"; for the argument "zero" the result is the function value 1, because δ (0) = 1 and<i>d (x ≠ 0) = 0.</i> The indices p, q go through all possible values ​​that lie within the mask image; that is, when displayed on a color LC display with XGA resolution eg for p values ​​from 1 to 1024 * 3 and for q values ​​from 1 to 768.

Does this propagate from the individual picture elements α_ij radiated light in a manner that is predetermined according to the invention arise within a viewing space, which is in front of the grid with the pixels α_ij A plurality of viewing positions, of which each viewer located within this viewing space, with one eye are predominantly picture elements α_ij a first selection and with the other eye predominantly picture elements α_ij a second selection from the views A_k (k = 1 ... n) sees, whereby the scene or the object is spatially perceived by the respective viewer.

The large number of such viewing positions is so large and the viewing positions are so close together, that viewers can move within the viewing space, while her eyes are almost always in such a viewing position, because the viewing positions respectively correspond to intersections of the defined predetermined propagation directions and the light rays visible to the eye have a small, however existing area cross-section.

In the context of this invention, the viewing area is to be understood as the area in which one or more observers are or move and, insofar as they are looking in the direction of the grid, can spatially perceive the scene or the object. Depending on the structure of the mask image and the number n of views A used_k (k = 1 ... n) viewing angles to the grid of over 45 ° are possible, ie the viewing space can have an opening angle of more than 45 ° starting from the mid-perpendicular of the grid.

This new method of autostereoscopic imaging differs significantly from the related art known in the art. While in the known methods partial information of a view should be visible only to one or the other eye of the observer, this new method deliberately allows partial information of one or more views to be visible to both eyes of the observer.

As a prerequisite for the spatial perception, the condition is fulfilled that one eye sees more partial information of the same view than the other eye. However, in compliance with the invention predetermined propagation directions is achieved that the number of "false", because actually the other eye attributable partial information does not exceed a limit from which the spatial perception is no longer possible in sufficient quality. It is advantageous, but not essential, to use perspective views as views of the scene / object. The use of orthogonal projections as views leads to excellent results.

For example, consider an object based on, by way of example, eight perspective views A_k (k = 1 ... 8) are shown in three dimensions, spatial perception is also ensured in high quality in accordance with the invention predetermined propagation directions of the plurality of viewing positions, because the right eye of the observer, although not exclusively, but predominantly picture elements α_ij with partial information as an example of the views A_one bis A_four and the left eye of the observer, although not exclusively, but predominantly picture elements α_ij with partial information of the views A_five bis A_eight perceives, where for the left eye in a limited number and pixels α_ij or parts thereof with partial information of views A_one bis A_four and for the right eye in a limited number of pixels α_ij or parts thereof with partial information of views A_five bis A_eight are visible.

The thereby visible for both eyes "wrong" picture elements α_ij Although in principle lead to a slight distortion of the three-dimensional impression, but this does not destroy the depth in the correct 3D impression within the viewing space.

This also results in a significant advantage of the method according to the invention, which is that its implementation and use is possible with arrangements using less commercially available series products, such as color LC displays both for the reproduction of the partial information on the pixels α_ij as well as for the generation of the mask image with wavelength filters β_why, are inexpensive to produce. If the subpixels R, G, B of a color LC display as picture elements α_ij and these serve the partial information of views A_k (k = 1 ... n), an amazing color fidelity and color brilliance can be achieved.

In particular, as compared to prior art spatial imaging techniques based on imaging optical elements such as lenticulars, the use of wavelength filters offers a number of significant advantages:

The filter elements do not produce an optical image and therefore no aberrations. On the other hand, optical images based on single-stage lens systems are always associated with aberrations. Aspherical lenses of the expansion of the filter elements in the filter array are currently not feasible with reasonable effort.

Furthermore, when using, for example, lenticular screens light reflections of ambient light points are always noticeable over the entire width of the lenticular surface, which is due to the shape of this surface. In contrast to this, in the method according to the invention punctiform ambient light sources are also only reflected punctiformly as an interference light reflection; Such effects can be further minimized by the use of anti-reflection layers on the support material of the filter array or on the filter array itself.

In lenticular procedures, the lenticulars depict the image elements for the viewer; more precisely, a picture element fills the viewer mostly the entire width of a lenticular, resulting in a "coarser" perceived size of the picture elements. By contrast, in the method according to the invention, each picture element visible to each viewer remains visible without optical imaging and thus without magnification.

The method according to the invention also has the advantage that, depending on the resolution of the screen used for image reproduction, it is possible to base the three-dimensional representation on virtually any number of but at least two views of a scene or an object.

In addition, it is possible to substantially improve the readability of displayed text compared to known black and white barrier methods. Namely, if, in an arrangement which is within the scope of this invention, wavelength-dependent mask image structures without opaque areas are used and ordinary text is laid, then in contrast to a black-and-white barrier for four views, on average only one part, viz a quarter of the displayed text area is visible - the text under each wavelength filter element β_why visible. This greatly facilitates text readability.

Moreover, in this case, for a three-dimensionally displayed image (eg, when using band-pass filters having a transmission of 100%), based on the average areal luminance, it may be about one third brighter than the same, but three-dimensional image generated with a black-and-white barrier ,

A particular advantage of the method according to the invention or the arrangements for carrying out this method is that wavelength filter arrays are relatively easy to produce in terms of manufacturing technology. For example, they can be printed or embossed onto glass or another carrier material, printed as a foil or generated by an exposure process. In a particular embodiment, a design as a holographic optical element is conceivable.

Advantageous optical properties of the wavelength filter arrays with regard to the adjustment continue to be advantageous for the advantage of favorable and versatile production possibilities. For example, a slight rotation of the filter array in the viewing direction does not necessarily produce strong and unpleasant moiré effects, which considerably reduces the assembly effort.

When transparent carrier materials are used for the wavelength filter arrays, beam offsets (parallel displacements) of the light propagation directions occur, which affect the spatial impression only negligibly. Furthermore, it affects the quality of the spatial perception only insignificantly, if the wavelength filter elements β_why not designed as an ideal filter (100% edge filter). It follows that currently available filter colors are also suitable with non-ideal characteristics for the production of the wavelength filter array.

The application of the method according to the invention is not limited to the light in the visible spectral range, but it can also be with a correspondingly modified wavelength filter array and portions of the invisible electromagnetic spectrum can be retained or transmitted and in this way, if a stereoscopic camera designed for these spectral regions is present at the location of the observer, obtained three-dimensional recordings and visualized after frequency conversion for visual evaluation. This results in numerous applications even for the medical field, namely, if, for example, a radiation dose with a predetermined wavelength is to be introduced into a specific spatial depth of a body.

Each wavelength filter element β_why can fixed predetermined transparency wavelengths / wavelength ranges λ_b have the wavelength of the of the associated or corresponding pixels α_ij coming light includes. Alternatively, however, also wavelength filter elements β_why be provided whose transparency wavelength / wavelength range λ_b is changeable depending on a control.

In this case, with appropriate programming of a drive circuit and a change in the filtering effect of the wavelength filter elements β_why during operation, which can be used advantageously to be able to adjust the autosteroscopic perceptibility of a displayed object to the individual impression of a viewer. This is done by changing the mask image. For example, a wavelength filter element β_why Depending on the control, a specific base color, for example R, can be transmitted optimally or not at all or in a brightness-dependent intermediate stage.

Also selected in this way are selected wavelength filter elements β associated with a given area of ​​the array_why as completely transparent as possible, whereby this area generates a two-dimensional representation of the scene or the object, while the remaining, still wavelength-filtered areas continue to reproduce a three-dimensional representation. Of course, it is also possible in this way, the entire scene / the entire subject by appropriate control of all wavelength filter elements β_why optionally two-dimensional or three-dimensional represent.

The latter can be achieved, for example, if a transparent color LC display is used as the wavelength filter array, which, like the color LCD display provided for image reproduction, has separately controllable subpixels R ', G' (for distinction). , B ', and this is assigned over the entire surface of the display expanding planar illumination. When the illumination is switched on then go from each subpixel R ', G', B 'radiations of the corresponding fundamental wavelength or corresponding wavelength / wavelength ranges.

Will now be an example for reproducing the picture elements α_ij provided color LC display with subpixels R, G, B serving as a wavelength filter array color LC display with subpixels R ', G', B 'upstream, so it can be achieved that the radiation coming from a subpixel R always only through subpixel R 'of the upstream color LC display can pass. If the subpixel R is the partial information of one of the views A_k (k = 1 ... n) associated with the straight lines through the surface centers of the subpixel R 'and the subpixel R, the propagation directions for the information of this pixel α_ij specified. In a figurative sense, this also applies to the subpixels G and G'bzw. B and B'zu.

In this way, by assigning partial information of the different views A_k (K = 1 ... n) to subpixels R, G, B of the imaging color LC display, the respective desired directions of propagation of the image information can be determined. Thus, with a simple structure, as will be explained in more detail below with reference to an exemplary embodiment, what was intended, namely the wavelength-dependent assignment of the picture elements α, can be achieved_ij one of the views A_k (k = 1 ... n) predominantly to one or the other eye of an observer.

In this respect, the invention also relates to an arrangement for the spatial representation of a scene / an object, in which for the reproduction of the picture elements α_ij a color LC display with separately controllable subpixels R, G, B is provided and coupled to a drive circuit, which on the subpixels R, G, B pixels of the views A_k (k = 1 ... n), in which further at least one array of a plurality of wavelength filters β_why is present, which, based on the viewing direction of a viewer, the color LC display at a predetermined distance z forward and / or downstream, in each case more of the wavelength filter elements β_why with one of the subpixels R, G, B correspond such that these wavelength filter elements β_why are transparent to the light emanating from the corresponding subpixel R, G, B and the directions of propagation of the light emanating from this subpixel R, G, B are defined by the positions of these wavelength filter elements β_why are determined.

The distance between the subpixels R, G, B on the color LC display to each other, the distance between the wavelength filter elements β_why within the array, and the distance z between the array of wavelength filter elements β_why and the color LC display in the viewing direction of a viewer are matched to one another such that the light emanating from the subpixels R, G, B passes through the corresponding wavelength filter elements β_why propagates in the determined directions so as to give a three-dimensional perceptible representation as described above.

Preferably, a color LC display is provided as a wavelength filter array and this coupled to a drive circuit, the subpixels R ', G', B 'in dependence on the parameters d_why, n_m and λ_b each of which the one wavelength filter element β_why associated wavelength λ_b the basic color of a subpixel R ', G', B 'and a corresponding subpixel R, G, B corresponds. As an additional wavelength range λ_b In addition to R, G, B, a completely opaque wavelength range λ for the visible light can be used_b be provided, which is referred to below with S.

It is expressly understood that the invention includes arrangements in which the wavelength filter array with respect to the viewing direction of a viewer to the serving for reproducing the picture elements color LCD display or upstream and also arrangements are conceivable in which the color LC display for reproducing the picture elements, both a wavelength filter array before and a wavelength filter array is arranged downstream.

The wavelength filter elements β_why may also be designed to be invariable in terms of their transparency behavior. Decisive and essential to the invention is that the subpixels R, G, B for reproducing the picture elements α_ij with wavelength filters β_why or subpixels R ', G', B 'correspond so that there are a plurality of propagation directions according to the above-mentioned method.

For particular applications, it may also be advantageous if in one or both grids, ie in the image forming grid (i, j) and / or on the wavelength filter array (p, q), the respective elements are also formed with pairs of different dimensions , For example, a particular wavelength filter element β_why be wider at the edge than a wavelength filter element β_why in the middle of the array.

Moreover, in the event that the wavelength filter array in the viewing direction in front of the imaging grid of pixels α_ij is arranged - this in width (and possibly height) to be corrected with a correction factor f, which is formed as follows: <maths id="math0005" num=""><math display="block"><mrow><mi>f</mi><mo>=</mo><mfrac><mrow><msub><mi>d</mi><mi>a</mi></msub></mrow><mrow><mi>with</mi><mo>+</mo><msub><mi>d</mi><mi>a</mi></msub></mrow></mfrac></mrow></math><img file="EP1689162A2_D0005.tif" /></maths> what d_a and z as defined in F3. If the wavelength filter array in the viewing direction behind the imaging grid of pixels α_ij is arranged, the correction factor f 'is used, which is formed after f' = 1 / f.

In a further preferred embodiment, it is provided that either the color LC display for displaying the picture elements α_ij or serving as a wavelength filter array color LC display is a flat illumination source is provided which emits substantially white light and whose areal extent corresponds approximately to the extent of the respective color LC display. In this case, color LC display and planar illumination source are connected to one another or positioned to each other that the outgoing light from the illumination source through the subpixels R, G, B and R ', G', B 'of the display radiated through and thereby filtered according to the fundamental wavelengths R, G, B.

With this arrangement, it is advantageously achieved that light of substantially equal intensity is emitted from each of the subpixels R, G, B in the direction of the associated subpixels R ', G', B 'or vice versa.

In a further particular embodiment, the planar illumination source is variable with respect to its light intensity, whereby it is possible to vary the intensity during the spatial representation of an object and thus to adapt the viewer individually, so as to optimize the spatial perceptibility.

In a concrete embodiment of the invention, the assembly consisting of the illumination source and the first in the viewing direction preceding array (ie LC display or filter array) may be formed by an electroluminescent display, a cathode ray tube, a plasma display, a laser-beam illuminated display, an LED display, a field emission display or a polymer-based display device. For example, a plasma display of the type Pioneer PDP-501 MX or Philips SFTV1.5-E; Model: 42PW9982 / 12 are used. Even large displays for stadium displays, rear projection displays or the like are conceivable.

Under certain circumstances, it is also advantageous if the previously described arrangement according to the invention in the viewing direction of a viewer is arranged upstream of a magnifying or downsizing lens, preferably a Fresnel lens. This ensures that the viewer is a real or virtual mapping of the arrangement for spatial representation arises.

A very special application of the invention described above is the ability to play on one and the same screen (eg a TV) simultaneously different image content (eg television programs) and assign each of these image content a separate propagation direction, from the view of the screen viewing only This image content is largely uninfluenced by the other image content is possible.

For example, a first image content in the first four views A becomes_one bis A_four reproduced, which may be four adjacent perspective views. A second image content is then in another four views A_five bis A_eight contain. If a correspondingly generated combination image is displayed with the arrangement according to the invention, the second image content can be spatially perceived from one viewing location from the first and from a second viewing location. Of course, in a special case, on the one hand, the views A_one bis A_four and on the other hand the views A_five bis A_eight each be identical to each other, so that the two image contents are indeed perceivable from different directions, but each two-dimensionally.

From the prior art it is known to demodulate the signals of several, but at least two television transmitters in the circuit arrangement of the same device, for example using corresponding satellite receivers. From these two television signals, the above-mentioned two different image contents are obtained, so that depending on the viewing position of one or the other image content over the entire surface can be viewed on the screen. Thus, it is possible for several people to watch different TV programs simultaneously on a TV. The respectively associated tones can eg be perceived via headphones or emitted via separate boxes to the viewing sites.

The invention still further relates to an arrangement for selectively spatial or two-dimensional representation of a scene / an object, wherein said means are provided with means for changing the transmission properties of the wavelength filter elements β_why Is provided. In this case, the wavelength filter elements β_why optionally for the purpose of a 3D representation according to the above-described rule for generating a mask image for a given transparency wavelength / wavelength range λ_b transmit or, for purposes of a 2D representation, as transparent as possible, that is as permeable as possible to the visible light, controlled.

In the specific case of using a color LC display as a wavelength filter array, this means that all RGB subpixels are controlled optimally transparent on the image section to be used as a 2D display, resulting in a quasi-white illumination section that is suitable for unimpaired 2D Impression.

Advantageously, in the aforementioned case, the drive circuit is designed so that either either only a selection of the wavelength filter elements β_why or the entirety of the wavelength filter elements β_why with regard to their transmission properties, whereby either the entire representation of the scene / object can be changed from the spatial to the two-dimensional representation or only selected display areas from the spatial to the two-dimensional representation.

This variability from a spatial to a two-dimensional representation and vice versa is advantageously achievable with an embodiment of the arrangement according to the invention, which comprises<ul id="ul0004" list-style="dash" compact="compact"><li>an image display device of a plurality of picture elements α_ijwhich represent information from a plurality of views of the scene / object in a predetermined assignment, wherein of the individual picture elements α_ij Light is emitted in different wavelength ranges,</li><li>a filter arrangement arranged in the viewing direction of an observer in front of or behind the image reproduction device with a filter array comprising a multiplicity of filter elements, which comprise both linear polarization filter elements and wavelength filter elements permeable in specific wavelength ranges β_why comprising, with a linear polarization filter and with a controllable optical medium arranged between the filter array and the linear polarization filter, which, in dependence on its actuation, causes a rotation of the polarization direction of linearly polarized light passing therethrough,</li><li>wherein the filter elements are arranged such that</li><li>in a first state of the optical medium in which the polarization direction effected by the optical medium and the polarization direction of the subsequent filter, ie of the linear polarizing filter elements of the filter array or of the linear polarizing filter, intersect each other, for the light emitted by the image display device defined light propagation directions are predetermined so that at a plurality of first observation locations predominantly information of a first selection or a first group of views and at a plurality of second observation locations, each of which is approximately at eye distance from an associated first observation location, mainly information of a second selection or a second group of views are perceptible, wherein a plurality of groups of views is possible, and</li><li>in a second state of the optical medium, in which the polarization direction effected by the optical medium and the polarization direction of the subsequent filter, ie the linear polarization filter elements of the filter array or the linear polarization filter, are substantially parallel to one another, the filter arrangement has increased transparency compared to the first state.</li></ul>

For switching between the 3D operation and the 2D operation, only the optical medium is to be actuated so that a rotation of the polarization direction is effected.

In order to specify the defined directions of propagation in the three-dimensional operating mode (3D operation), the optical medium, as a result of a predetermined activation, assumes the filter following in the direction of the passage of light, which, depending on the arrangement, is formed either by the linear polarization filter elements of the filter array or by the linear polarization filter, such a condition, that as a result of the intersecting polarization directions a most extensive extinction for the regions of the linear polarization elements takes place. As a result, a strong structuring of the light passing through the filter arrangement can be effected.

This patterning can be canceled by an operation of the optical medium by bringing it into a state in which the polarization direction effected by the optical medium is substantially parallel to the subsequent filter, i. h. no or at most a slight weakening of the light intensity by the filter arrangement occurs. The linear polarization elements which are opaque in the three-dimensional mode in cooperation with the optical medium and the linear polarization filter thus become translucent in the two-dimensional mode. By a suitable arrangement of these linear polarization elements, a substantially homogeneous light throughput is achieved by the filter arrangement. As a result, images generated by the image display device can be perceived in the resolution of their reproduction.

Preferably, the controllable optical medium for rotation of the polarization direction comprises liquid crystals, resulting in a particularly simple and cost-effective solution. For example, LC panels known per se, but without polarization filters, can be used for this purpose. Furthermore, rotatable Linearpolarisationsfilter or piezoelectric elements can be used. As optical media for polarization rotation, it is also possible to use those based on the Pockels effect, the Kerr effect or the Faraday effect.

A particularly favorable manufacturable structure of the filter array results when all Linearpolarisationsfilterelemente have the same polarization direction. In addition, then the structure of the optical medium remains simple and the effort when switching low.

The structure of the wavelength filter array and / or the optical medium can also be chosen so that a switch is carried out in principle only on certain parts of the arrangement. This can be advantageous if, for example, a certain image component should always be perceived two-dimensionally or always three-dimensionally.

The filter arrangement is advantageously arranged in the viewing direction of a viewer in front of the image display device. The image display device is optionally arranged downstream of a planar illumination source which emits white light. The observer thus sees through the filter arrangement that emitted by the image display device, for example a color LC display or the light shining through it. However, it is equally possible, the filter arrangement between the illumination source and the image display device or to arrange the color LC display. In this case, the color LC display and the filter arrangement can advantageously be combined to form a structural unit. The distance z between them is on the order of 1 mm to 10 mm and is determined depending on the grid used for the picture elements and the filter elements, the average pupil distance of a normalized viewer and a desired viewing distance.

The variability from a spatial to a two-dimensional representation and vice versa is also advantageously achievable with the further embodiment of the arrangement according to the invention described below. This embodiment comprises<ul id="ul0005" list-style="dash" compact="compact"><li>an image display device of a plurality of picture elements α_ijwhich represent information from a plurality of views of the scene / object in a predetermined assignment, wherein of the individual picture elements α_ij Light is emitted in different wavelength ranges, arranged in the viewing direction of a viewer on the image display device filter arrangement with a filter array, the β in certain wavelength ranges permeable wavelength filter elements_why comprising, and arranged with a viewing direction behind the image display device and in front of the filter array lens, which is switchable between a transparent position and a scattering position,</li><li>wherein the wavelength filter elements β_why arranged in such a way that in the transparent position of the lens for the light emitted by the image display device defined propagation directions are given, so that predominantly information of a first group of views and at a second observation location at eye distance from the first observation location information of a second group of views are perceptible at a first observation location, a plurality of such places exist with different such groups, and in the scattering position of the diffusing screen the structuring of the light passing through the filter array is substantially reduced with respect to the first position.</li></ul>

To switch between the 3D mode and the 2D mode, only the lens is to be operated. The specification of the defined propagation directions in the three-dimensional mode of operation takes place in the transparent state of the lens over the filter array. Thereby, the above-mentioned strong structuring of the light passing through the filter assembly can be effected. This structuring of the light can be achieved again by an operation of an optical medium, ie here by the spreading disc pick up by this is scattered translucent. As a result, a largely homogeneous light throughput is achieved by the filter arrangement, so that images generated by the image reproduction device are perceptible in the resolution of their reproduction. Such lenses, which are controlled electronically, are known per se and therefore require no further explanation for the expert.

Again, the structure of the wavelength filter array or the structure of the lens can be chosen so that a switch is carried out in principle only on certain parts of the arrangement. This can be advantageous if, for example, a certain image component should always be perceived two-dimensionally or always three-dimensionally.

Advantageously, the wavelength filter array is designed as a passive, ie without any electrical energy auskommender filter. The wavelength-filter array can be made, for example, as a thin-walled plate or foil into which the desired structure of wavelength filter elements β_why permanently imprinted. The use of such filter arrays allows significant cost savings over color LC displays. In addition, moire effects resulting from the use of two similar color LC displays are avoided. Preferably, filter arrays are used whose individual wavelength filter elements β_why each have a polygonal, preferably a rectangular outline.

In this as well as in other embodiments of the invention, the wavelength filter arrays preferably consist exclusively of wavelength filter elements β_whywhich are transparent or opaque in one of the three color ranges red, green or blue or in the entire spectrum of visible light. This can be compared to known black and white barriers due to the overall greater light transmission, the readability of displayed text be significantly improved. This can also be achieved with wavelength filter arrays consisting exclusively of wavelength filter elements β_why which are transparent or opaque in two of the color ranges red, green or blue or in the entire spectrum of visible light. Moreover, some of the wavelength filter elements β_why also be designed as a combined wavelength and linear polarization filter or as a pure linear polarization filter.

The optionally between the wavelength filter elements β_why provided linear polarization of the filter array act depending on the control of the optical medium as opaque or transparent filter elements.

However, the above-described positive aspect of the apparatus simplification can also be achieved with a filter array in which only those filter elements are provided which are either opaque or transparent in the entire spectrum of visible light.

Advantageously, a color LC display with separately controllable subpixels is also provided here as a picture display device, one subpixel each being assigned to one picture element α_ij equivalent. In 3D operation, the filter arrangement causes a selective perception of these picture elements α_ij causes the image display device.

From every viewing position, a viewer with one eye predominantly takes picture elements (α_ij a first selection and with the other eye predominantly picture elements α_ij a second selection from the views A_k (k = 1 ... n) true, provided that the assignment of partial information of the views A_k (k = 1 ... n) to picture elements α_ij as well as the positioning of these pixels α_ij is performed on the grid as already described after the function (F1) and the structuring of the wavelength filter elements β_why to a mask image - analogous to the combination of the partial information of the different views A_k (k = 1 ... n) to an overall picture - also here according to the rule (F2) takes place.

Regarding the variability of one of the spatial to a two-dimensional representation and vice versa, the arrangement according to the invention may comprise in a further embodiment in addition to an image reproduction device already described<ul id="ul0006" list-style="dash" compact="compact"><li>a filter arrangement having at least two static filter arrays arranged in parallel one behind the other and arranged upstream or downstream of the image display device at a predetermined distance z, the filter arrays each having a multiplicity of filter elements transparent to specific wavelength ranges and / or specific polarization directions β_why respectively,</li><li>a device for displacing at least one of the filter arrays perpendicular to the viewing direction from a first position relative to the second filter array to a second position relative to the second filter array,</li><li>wherein the individual filter elements β_why are arranged on the filter arrays such in the first position, the filter arrangement for the light emitted by the image reproduction device predetermines propagation directions in such a way, that at a first observation location predominantly information of a first group of views and at a second observation location at eye relief from the first observation location predominantly information of a second group of views are perceptible and wherein a plurality of such locations exist with different groups, and in the second position, the filter assembly has increased transparency over the first position.</li></ul>

The filter elements β_why may also be formed here as passive filter elements and / or as passive linear polarization filter elements. Preferably, the filter elements are designed as passive filter elements.

For switching between the 3D operation and the 2D operation, only the displacement device is to be actuated, with which the preferably two filter arrays are shifted from one another. In addition, eliminating the use of two static filter arrays of the entire effort for the control of the individual filter elements β_why, This results in a considerable simplification of the driving effort of the arrangement.

The mechanical displacement device used is preferably a piezo-actuator device, which has a very precise offset of the filter arrays by the very small longitudinal distances of the individual filter elements β_why allowed, so that when switching between the two positions of the filter assembly, the filter arrays with their screening are each aligned exactly to each other. With the piezo actuator, a parallel offset of the filter arrays in the order of 100 microns can be precisely maintained. In an alternative embodiment, a stepping motor is used instead of a piezo actuator.

The filter arrays can also be designed here as passive filters, ie without any electrical energy, and be produced in the form of thin-walled plates or foils into which the desired structure of the filter elements β_why permanently imprinted.

However, the above-described effect of the apparatus simplification can also be achieved with a filter arrangement comprising a plurality of filter arrays, each exclusively of the entire spectrum of visible light opaque or transparent filter elements β_why consist.

In an advantageous embodiment of the invention, a color LC display with separately controllable subpixels is provided as a picture display device, one subpixel each corresponding to one picture element.

In 3D operation, the filter arrangement causes a selective perception of the picture elements α_ij on the image display device as already described above, wherein a picture element α_ij Again, a self-luminous or illuminated area with an area of ​​about 10,000 microns² up to a few mm² corresponds to a small section of one of the views A_k (k = 1 ... n) can be reproduced at the point i, j.

For some applications, a mode is desirable in autostereoscopic displays, in which only selected sections of the scene or the object shown can be perceived three-dimensional, while the remaining part is perceived two-dimensionally. In many cases, it is also desirable to be able to locally vary the respective two- or three-dimensional reproduced sections within the overall representation.

Starting therefrom, a further embodiment of the invention provides means for switching between a plurality of different operating modes, in which the illumination light is either only used for the purpose of two-dimensional representation exclusively by the image elements of the image display device, However, not through filter elements of the wavelength filter array passes through to the viewer or for the sake of three-dimensional representation by at least a portion of the filter elements of the wavelength filter array and subsequently by an associated part of the pixels α_ij passes through to the viewer.

With this arrangement, the scene or the subject may be selectively displayed to the viewer such that either total two-dimensional or three-dimensional perception is possible. Deviating from this, however, it is still possible to only one or more image sections three-dimensional, to represent the rest of the picture in two dimensions namely, when an operating mode is selected, at only in some areas, corresponding to the three-dimensional image sections, the illumination light passes through the filter elements of the wavelength filter array as well as subsequently also through the associated image elements of the image display device to the viewer.

As means for switching between the different operating modes, for example, a first planlight source is provided in the viewing direction of the viewer between the picture display device and the wavelength filter array and behind the wavelength filter array a second planight source and both planlight sources are coupled to separately controllable on / off switches.

This can be achieved in a simple manner depending on the control of the on / off switch, that in a first operating mode for the purpose of two-dimensional representation, only the first planlight illumination source is switched on and illumination light only by the image display device, However, not through the wavelength filter array passes through the viewer and in a second mode for the sake of three-dimensional representation, only the second plan illumination source is turned on and illumination light always passes through the wavelength filter array and the image display device to the viewer.

The scene or the subject matter is in this case two-dimensional overall for the viewer when preselecting the first operating mode, and three-dimensionally perceptible in the case of preselection of the second operating mode.

In another related embodiment, the wavelength filter array is associated with a grid of a plurality of individually controllable shutter elements, wherein depending on the number of controlled shutter elements, the path of the illumination light generated by the second planlight source is interrupted or released by a larger or smaller number of filter elements.

With this and in conjunction with the above-mentioned on / off switches, three operating modes can be realized. Thus, it can be achieved that in a first operating mode in which only the first planlight illumination source is switched on and illumination light only reaches the viewer through the image display device but not through the wavelength filter array, the entire image can be perceived two-dimensionally.

In a second mode of operation, again, only the second planlight source is turned on and the illuminating light always passes through the wavelength filter array and the picture display device to the viewer, whereby the entire picture can be perceived three-dimensionally, as long as the shutter elements are opened.

In a further third operating mode, both planlight sources are switched on and a predetermined number of shutter elements are activated, that the illuminating light ( "open") in areas of the controlled shutter passes through both the filter elements as well as by the associated image elements throughout, and consequently a predetermined propagation direction, while the illumination light in areas of the non-driven ("unopened") shutter elements pass only through the image display device, however, does not reach the viewer through assigned filter elements and therefore not with a predetermined propagation direction. As a result, the scene / object is two-dimensionally perceptible with respect to the areas of the non-controlled shutter elements, but can be perceived three-dimensionally with a view to the areas of the controlled shutter elements. In this case, it may be provided in a particular embodiment to couple one or both plan lighting sources to dimmers, whereby the respective output brightness is adjustable and can be adjusted so that the brightness of the first planlight source, preferably about a factor of three, is less than the brightness of second planlight source.

Here, the first planlight source preferably consists of a plate-shaped light guide, which is bounded by two opposing large surfaces, of which a first to the image display device, the second to the wavelength filter array, as well as circumferential narrow surfaces. This light guide is fed by at least one light source whose radiation is coupled through one or more of the narrow surfaces in the light guide. Within the light guide, the radiation is reflected back and forth partly due to total reflection at the two large areas and partly emitted as useful light over the first large area. In this way, large-area plan lighting sources for large-scale image display devices can be produced.

In the case of a plan illumination source constructed in this way, the second large area of ​​the light guide can advantageously be provided with a coating which interferes with the total reflection and whose interference is inhomogeneous over the extent of the second large area between two limit values, the limit values ​​being dependent on the density d of the coating and the density d is a measure of the mean distance of the particles per unit area.

In this way, the light density distribution can be influenced in a simple manner with little technical means and a desired light density distribution can be generated across the radiating large area. The underlying functionality can be explained as follows:

With each reflection on the first large area within the light guide, only a portion of the radiation is reflected back into the light guide as a result of total reflection, while a remaining portion continuously emerges as useful light through the first large area. With the invention applied to the opposite second large area coating the total reflection is disturbed by the reflection behavior is changed by influencing the failure angle at the second large area so that more light hits at an angle to the radiating large area, in which the total reflection no longer take place there can and thus a larger amount of light passes as useful light to the outside.

The light guide is a transparent body, which consists for example of glass or PMMA and thus of a denser medium than the surrounding air. It is known that where the surface of a light guide comes into close contact with adjacent substances or objects, the total reflection is disturbed and stray radiation is the result. This is basically undesirable in optical fiber technology. However, the present embodiment of the invention utilizes this effect to disturb the total reflection at the second major surface of the plate-shaped lightguide in such a way that the disturbance in different areas of the large area is also different, as shown below.

The differentiated Störvermögen in different areas of the second large area can be given by way of example so that with increasing distance x from a narrow surface into which the light is coupled, the Störvermögen the coating is increasingly stronger. In this case, the disturbance can be progressively formed in increasingly parallel to this narrow surface aligned strip-shaped surface sections.

Thus, it can be provided that in a first surface portion near the narrow surface, a coating is applied, wherein the average distance of the particles per unit area is large and thus the disturbance of total reflection is relatively low. In the next parallel thereto aligned surface portion, for example, at a distance x_one Starting from the narrow surface, the average distance of the particles per unit area is smaller than in the first surface section and thus the disturbance of the total reflection is more pronounced. In a third area section, starting at a distance x₂ of the respective narrow area, the mean distance of the particles per unit area is again lower, d. h. There are more particles per unit area, with the result that the total reflection is disturbed even more in this area. This continues in this way over the entire second large area, wherein the farthest from the respective narrow surface area section has the largest density of particles per unit area and thus the disturbance is there most pronounced.

Although the total reflection is the least disturbed near the narrow surface into which the light is irradiated, a sufficiently large proportion of the light is coupled out by the radiating large surface due to the greater light intensity still present there. With increasing distance from the narrow surface and with increasing density of the particles in the coating, however, the total reflection is progressively increasingly disturbed, so that in each of the areas of the radiating large surface, which face these surface portions, despite the already lower light intensity effectively about as large Proportion of light is decoupled, as close to the narrow surface.

In this way, it is possible to achieve an almost homogeneously luminous large area which has at least three times the measurable luminance per unit area than is the case with comparable prior art plan illumination sources. This is particularly noticeable in very large-area optical fibers, which is advantageous for large-screen images.

An even further increase in brightness is possible with a further embodiment variant in which the disruptive power of the coating increases with increasing distances x_one and x₂, Starting increasingly from two narrow surfaces, in each of which light is coupled, is increasingly stronger. It can be two narrow surfaces, which are parallel to the light guide. Also in this case, the coating may be formed so that the interference increases progressively in parallel to each other and the narrow surfaces aligned strip-shaped sections, up to a maximum, which is approximately in the middle of the longitudinal extent of the second large area.

Preferably, a coating is applied externally to the second large area as a coating. This results in simple possibilities for applying the coating, which have already proven themselves technologically and which provide a sufficient coating for many applications. The local paint density is an equivalent for the disturbance at this location. The lacquer density can be defined according to the function d = f (x), where x is the measure of the distance from the narrow surface into which the light is coupled, while d corresponds to a density value. In this case, for example, d = 1 for a completely painted area and d = 0 for an unpainted area of ​​the second large area.

In an advantageous embodiment, as a density function <maths id="math0006" num=""><math display="block"><mrow><mi mathvariant="normal">d</mi><mo>=</mo><mi mathvariant="normal">f</mi><mrow><mo>(</mo><mi mathvariant="normal">x</mi><mo>)</mo></mrow><mo>=</mo><msub><mi mathvariant="normal">a</mi><mn>3</mn></msub><mo>⋅</mo><msup><mi mathvariant="normal">x</mi><mn>3</mn></msup><mo>+</mo><msub><mi mathvariant="normal">a</mi><mn>2</mn></msub><mo>⋅</mo><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup><mo>+</mo><msub><mi mathvariant="normal">a</mi><mn>one</mn></msub><mo>⋅</mo><mi mathvariant="normal">x</mi><mo>+</mo><msub><mi mathvariant="normal">a</mi><mn>0</mn></msub></mrow></math><img file="EP1689162A2_D0006.tif" /></maths> be predetermined, the parameters a₀, a_one, a₂ and a₃ are selectable. For example, the parameters a₀= 0, a_one = 4, a₂ = -4 and a₃ = 0 proven.

This embodiment of the invention is not necessarily limited to polynomials of the third degree; In individual applications, it may also be useful to strive for a density function in the form of a polynomial higher than the third degree.

Another embodiment is conceivable in which the density d is predetermined not only as a function of the distance x from the narrow surface into which the light is coupled, but also as a function of the coordinate y extending perpendicular thereto. Then, for example, the paint density is defined according to the function d = f (x, y), where x is a measure of the distance from the narrow surface into which the light is coupled, but y is a measure of a position perpendicular to this, as already described above Distance. Thus, for each location x, y on the second large area, the density of the coating can be specified and influenced on the amount of light that emerges in an opposite area through the radiating large area.

The density function d = f (x, y) may be of particular interest if a very specific luminance profile is to be generated across the radiating large area. Thus, with the function d = 1 for [0.4 &lt;x &lt;0.6 and 0.4 &lt;y &lt;0.6], otherwise d = 0, a particularly bright spot can be achieved approximately in the middle of the radiating large area, if the values ​​x and y are also normalized here, ie if, for example, x holds_me= y_me=0, x_max= y_max=. 1 In this way, very high luminances can be achieved in this middle spot.

The application of the paint on the outside of the second large area can be achieved by a conventional printing process, for. Example, by screen printing, by an image corresponding to the density function are generated, which includes the entire second large area, which again applies here d = 1 for a fully painted area unit and d = 0 a not provided with paint area unit. The generation of this image may optionally be based on a gradation curve.

In a modified embodiment, the entire second large area can be painted homogeneously from the outside, ie provided with a coating of uniform density. Then a lot of light is coupled out by the radiating large area, but inhomogeneities occur because near the incident light source, the intensity is greater.

In another related embodiment is provided in that the coating is formed from a multiplicity of particles with higher and particles having a lower level of interference, which are in predetermined proportions to one another, where in surface areas, in which the total reflection should be disturbed more, the particles with higher impurities and in surface areas, in which the total reflection is less disturbed, the particles with less disturbance predominate. It is very advantageous to use dull silver particles as particles with a higher degree of interference and shiny silver particles as particles with a low level of interference.

Furthermore, it can be provided that portions of the coating are recessed and the second large area in these subregions has the highest possible light transmission. In special cases, these sections may be arranged in regular, freely selectable patterns.

In a further development, an arrangement is preferred in which, in the viewing direction of a viewer, first a translucent image display device (eg a color LC display), then a wavelength filter array and then a light source is arranged. Here, the wavelength filter array is provided on its side facing the image display device with reflective or scattering surface elements and there is at least one light source, whose radiation in the first operating mode is directed only to the side of the wavelength filter array facing away from the observer, is directed in the second mode only to the side of the wavelength filter array with the reflective or scattering surface elements and in the third mode is directed only to selected areas of the side facing away from the viewer side of the wavelength filter array.

Again, a three-dimensional representation is generated in the first mode, since the illumination light passes through both the wavelength filter array and the image display device to the viewer. If a combination image from several perspective views of the scene / object is shown on the image-representing grid of the image display device, the viewer sees the three-dimensional impression for the reasons already explained, namely because for each eye of the observer, influenced by the positions of the filter elements relative to the Positions of assigned picture elements or only associated image information from the perspective views are visible through the thus defined propagation directions of the light.

In contrast, in the second mode of operation, the illuminating light does not pass through the filter elements and subsequently through the picture elements, but strikes the observer-facing side of the wavelength filter array, there the specular or diffusing surface elements and, consequently, from that side of the wavelength filter array Direction of the image display device reflected or scattered there, passes through the translucent picture elements and reaches both eyes of the beholder. Thus, a direction selection or an association of image information to the right or left eye of the viewer does not, with the result that the representation of the scene / the object is perceived by the viewer not three-dimensional, but two-dimensional.

In this way it is possible with relatively simple means to produce a full-surface two-dimensional representation or a full-surface three-dimensional representation of the scene / the object.

If a grid of individually controllable shutter elements is arranged analogously to the embodiment already described above, the shutter elements corresponding at least approximately to the size of a filter element or a picture element, then it is also achieved that the illumination light directed onto the surface elements is triggered by triggering predetermined shutter elements can be blocked in sections.

In this embodiment, in a third operating mode in which a number of shutter elements are not activated ("unopened") in a region of the image surface, a viewer perceives a image section corresponding to this surface region two-dimensionally true.

On the other hand, the light passes through the other controlled ("open") shutter elements, then through the wavelength filter array and also through the image display device, whereby the viewer perceives the image sections corresponding to these surface sections three-dimensionally.

In this way, it is also possible here with relatively simple means to simultaneously generate an image-wise two-dimensional or three-dimensional representation of the scene / object.

The illumination light may emanate from two independent light sources, the radiation from one of the first two light sources being directed exclusively at the side facing away from the observer and the radiation from the second light source only at the side of the wavelength filter array facing the observer and provided with surface elements.

In order to be able to direct the illumination light in the manner indicated on the wavelength filter array or on the image reproduction device, each of the two light sources can be assigned a controllable on / off switch. The control of the on / off switch or the shutter elements, which may be parts of an LC-Shutters, can be made by means of PC and corresponding software, which specifies the switching states for the desired operating modes.

It is also possible provide only one light source instead of the two separately switchable light sources and to arrange swivel-mounted reflectors, by the radiation emanating from this light source in a first pivot position only on the side of the wavelength filter array facing away from the observer, in a second pivot position only on the side of the wavelength filter array with the reflective or scattering surface elements and in a third pivot position of the emanating from this light source radiation both on the side facing away from the viewer side of the wavelength filter array and on the side of the wavelength filter array directed to the reflective or scattering surface elements. This and in conjunction with controllable shutters, which are positioned in the beam path between the light source and the reflectors, the aforementioned three modes can be realized.

Preferably, the wavelength filter array is designed as a static filter and the reflective or scattering surface elements are positioned exclusively on the opaque surface areas of the static filter.

In order to enable a simplified construction, in particular for large-format screens, for example for plasma screens with 50-inch screen diagonal, the invention can be designed such that the filter arrays consist of neutral filters for wavelength-independent attenuation of the light intensity, wherein for each filter a certain transmittance is predetermined. The transmittances 0%, 25%, 50%, 75% and 100% are preferably used, whereby the readability of displayed text is also significantly improved here compared with known black-and-white barriers due to the greater light transmittance overall.

Moreover, some of the filter elements may also be formed as combined neutral and wavelength filter elements, ie with wavelength-dependent transmittances. In concrete terms, this means that the corresponding filters with such transmission properties allow only light of certain transparency wavelength ranges to pass through and at the same time also attenuate its intensity.

In this context, it should be understood that the term "transmission properties" includes all possible properties of the filters used herein. Each of the filters therefore has a very specific transmission characteristic λ_b on. As explained above, this can be, in particular, a wavelength-independent weakening of the light intensity with a certain transmittance or a wavelength-dependent (optimal) transparency or a combination of both, ie a wavelength-dependent weakening of the light intensity with a specific wavelength-dependent transmittance.

Optionally, it is also possible here wavelength filter elements β_why to be used, which are permeable to light of certain wavelength ranges. Preferably, these wavelength filter elements are β_why in one of the three color areas red, green or blue transparent. For example, wavelength filter elements β_why are used, which are transparent in two of the color ranges red, green or blue. The optional wavelength filter elements β_why Have transparency wavelength or transparency wavelength ranges, preferably the wavelength or wavelength range λ of the corresponding pixels α_ij corresponding to radiated light.

In order to use for the construction of the inventive arrangement not expensive electrically conductive and at the same time optically transparent panes, as they are used in plasma screens, a filter array located in front of a flat screen is provided in which at least every tenth filter element is electrically conductive. This already reaches a sufficient overall conductivity.

To produce the filter structure, for example, a printable and at the same time electrically conductive paint can be used (eg SPI Conductive Carbon Paint; Hersteller: Structure Probe, Inc., USA). Further suitable for the formation of opaque filter elements on the filter array, in particular metal particles in question, which are applied to an adhesive surface. It is also possible to form the material constituting the filter structure together with a substrate as a photographic film or plate having corresponding electroconductive properties.

The carrier material for the filter array may be a transparent plastic (eg PMMA), glass or a transparent film. The carrier material is located either on only one side of the material or on both sides of the material forming the filter structure. This results in a quasi-sandwich of a first layer of the carrier material, filter array and a second layer of the carrier material. Preferably, the carrier material is fitted with the filter array in the frame of the flat screen.

Advantageously, all electrically conductive filter elements present on the filter array can be connected to one another in an electrically conductive manner. Furthermore, it can be provided that all electrically conductive filter elements are connected to at least one electrode, via which the filter array can be included in an electrical circuit.

A first method for producing a filter array in which at least one tenth filter element is electrically conductive comprises, for example, the following method steps: preparing a screen printing mask using an electrically conductive ink, wherein at least one tenth non-transparent predetermined filter element is produced by means of this conductive ink; Screen printing the filter structure on a transparent substrate, eg PMMA or glass and, if necessary, repetition of the above-mentioned process steps.

A second method for producing a filter array in which at least one tenth filter element is electrically conductive comprises, for example, the following method steps: Preparing a printing mask using metallic particles, eg Silver particles, wherein at least every tenth non-transparent predetermined filter element is formed by means of said particles; Coating a transparent support material, eg PMMA or glass, with a transparent adhesive (eg Acrifix 192 adhesive, manufacturer: Röhm GmbH, Darmstadt, Germany); Imprinting the filter structure on the substrate and, if necessary, exposure, eg UV exposure, in order to cure the adhesive.

Further methods for forming a filter array with the mentioned properties are conceivable. It is crucial that the material for forming at least every tenth filter element is electrically conductive. Preferably, all non-transparent filter elements are formed electrically conductive.

In the context of the invention, it is further to provide an additional equipment comprising: means for detecting the eye position of a viewer selected from a group, a device for shifting the filter array perpendicular to the viewing direction of this viewer and a computing device, which the displacement device in dependence on the determined Eye position of the viewer pressed. This ensures that the observer concerned almost exclusively the middle of the views A due to the permanently matched to his eye position position of the filter array_k (k = 1 ... n) sees.

To detect the eye position of a selected observer (so-called "tracking"), various devices may be used, as described inter alia in WO 96/18925. In a simple embodiment, a pivotable camera with a computing device is sufficient; the computing device evaluates the signal supplied by the camera, eg the eyes are searched for as white areas with dark spots corresponding to the pupils. It is also possible to mark the selected viewer preferably between the eyes with a specially colored dot or other technically recognizable feature. The selected viewer may, for larger screens (eg Plasma displays with 50 inches screen diagonal) can be easily identified by the fact that he is staying in a particular viewing area, for example, the available tracking volume of the tracking device.

For displacement of the filter array, for example, a device is provided which comprises at least one rail and at least one linear motor, which is preferably designed as a stepping motor. The displacement of the filter array is preferably in the horizontal direction - relative to the (ordinary) viewing direction of a viewer; however, a vertical shift is also conceivable. But it is also possible to make the shift using piezo actuators.

In a particular embodiment, it is provided to provide the selected viewer in advance with a test image in order to calibrate the system. This may be useful in terms of the size of the observer, since different views are presented at vertically different, but horizontally in front of the screen same viewing positions.

<u style="single">Brief description of the drawings</u>

The invention will be explained in more detail with reference to embodiments. In the accompanying drawings show:<dl id="dl0001" compact="compact"><dt>Fig.1</dt><dd>an embodiment variant in which, in the viewing direction of a viewer, first a first color LC display is arranged as an image-representing screen and at a predetermined distance z behind a second color LC display as a wavelength filter array,</dd><dt>Fig.2</dt><dd>an example of a mask image generated with the wavelength filter β_why used subpixels R'G'B 'of the second color LC display, greatly enlarged and not drawn to scale,</dd><dt>Fig.3</dt><dd>an example of an overall picture from the partial information of the views A_k (k = 1 ... n), generated with the image elements α_ij used subpixels RGB of the first color LC display, greatly enlarged and not drawn to scale,</dd><dt>Fig.4</dt><dd>the structure of a mask image according to FIG. 2, which is formed exclusively by red subpixels R ',</dd><dt>Fig.5</dt><dd>the positions of the partial information from the views A_k (k = 1 ... 8), which in the overall picture according to FIG. 3 are represented by red subpixels R,</dd><dt>Fig.6</dt><dd>the visible partial information or parts thereof for an eye of an observer when looking from one of the viewing position through the mask image from FIG. 4,</dd><dt>Fig.7</dt><dd>the visible partial information or parts thereof for the other eye of the observer when looking from one of the viewing position through the mask image from FIG. 4,</dd><dt>Fig.8</dt><dd>an embodiment deviating from the design variant according to FIG. 1, in which, instead of the second color LC display, an array of wavelength filter elements β_why fixed predetermined transparency wavelengths or transparency wavelength ranges λ_b is provided,</dd><dt>Fig.9</dt><dd>a section through an arrangement shown in Figure 8 with the conditions of Figure 2 and Figure 3,</dd><dt>Fig.10</dt><dd>a different from the embodiment variant of Figure 1 embodiment in which in the viewing direction of the observer initially an array of wavelength filter elements β_why fixed predetermined transparency wavelengths / wavelength ranges λ_b and at a distance z behind the image-forming color LC display are positioned,</dd><dt>Fig.11</dt><dd>an example for the realization of the moiré effect,</dd><dt>Fig.12</dt><dd>an example of the mask image structure of a black and white barrier known from the prior art,</dd><dt>Fig.13</dt><dd>an example of an RGB mask image structure,</dd><dt>Fig.14</dt><dd>a first embodiment of the inventive arrangement with means for 3D-2D switching, comprising a filter arrangement consisting of a filter array, an optical medium for rotation of the polarization direction and a linear polarization filter,</dd><dt>Fig.15</dt><dd>a second embodiment of the inventive arrangement with means for 3D 2D switching, comprising a lying in the direction of view of a viewer in front of a picture display device filter assembly consisting of a linear polarization filter, an optical medium for rotation of the polarization direction and a filter array,</dd><dt>Fig.16</dt><dd>an example of the structure of a filter array with linear polarization elements and wavelength filter elements β_why in greatly enlarged and not to scale representation.</dd><dt>Fig.17</dt><dd>A third embodiment of the inventive arrangement with means for 3D 2D switching, comprising a lying in the direction of view of a viewer behind a picture display device filter assembly with lens,</dd><dt>Fig.18</dt><dd>a primitive of a first wavelength filter array,</dd><dt>Fig.19</dt><dd>a primitive of a second wavelength filter array,</dd><dt>Fig.20</dt><dd>a first wavelength filter array composed of a plurality of basic elements according to FIG.</dd><dt>Fig.21</dt><dd>a second wavelength filter array composed of a plurality of basic elements as shown in FIG</dd><dt>Fig.22</dt><dd>a summary wavelength filter array generated by superposing the wavelength filter arrays shown in FIGS. 20 and 21,</dd><dt>Fig.23</dt><dd>a further summary wavelength filter array resulting from the summing wavelength filter array according to FIG. 22 after displacement of the two superimposed wavelength filter arrays from FIG. 20 and FIG. 21 by three grid positions,</dd><dt>Fig.24</dt><dd>an example of a wavelength filter array containing only opaque and transparent wavelength filter elements β_why contains</dd><dt>Fig.25</dt><dd>a filter arrangement which results from a staggered superposition of seven wavelength filter arrays according to FIG.</dd><dt>Fig.26</dt><dd>An embodiment of the arrangement according to the invention with means for optionally full-surface two-dimensional or full-surface three-dimensional representation, comprising an image display device, a wavelength filter array and plan lighting sources,</dd><dt>Fig.27</dt><dd>An embodiment of the arrangement according to the invention with means for either full-surface two-dimensional, full-surface three-dimensional or fragmentary two- or three-dimensional representation,</dd><dt>Fig.28</dt><dd>the configuration of one of the planlight sources in FIG. 27 as a planar light guide with a light source,</dd><dt>Fig.29</dt><dd>an example of a possible structuring of the density d of the coating in the planlight source according to FIG. 28 in a greatly enlarged representation,</dd><dt>Fig.30</dt><dd>an example of the equipment of the plan illumination source according to Fig. 28 with a further light source for coupling light into the light guide,</dd><dt>Fig.31</dt><dd>an example of a possible structuring of the density d of the coating in the planlight illumination source according to FIG. 30 in a greatly enlarged representation,</dd><dt>Fig.32 to Fig.34</dt><dd>Examples of different density distributions during execution of the planlight source according to FIG. 28 and coating according to FIG.</dd><dt>Fig.35</dt><dd>an example of the density distribution during execution of the plan illumination source according to FIG. 30 and coating according to FIG.</dd><dt>Fig.36</dt><dd>the arrangement according to the invention according to Fig. 27 with integrated planlight source in the embodiment according to Fig. 28, but without coating,</dd><dt>Fig.37</dt><dd>an example of the equipment of the lighting device with scattering or reflecting surface elements,</dd><dt>Fig.38</dt><dd>a further example of the equipment of the lighting device with scattering or reflecting surface elements, a flat light source and additional reflectors,</dd><dt>Fig.39</dt><dd>an example of the structure of the filter elements β_why in greatly enlarged and not to scale representation with the exclusive use of neutral filters,</dd><dt>Fig.40</dt><dd>another example of the structure of the wavelength filter elements β_why in a greatly enlarged and not to scale representation when using neutral filter and wavelength filter elements,</dd><dt>Fig.41</dt><dd>another example of an overall picture from the partial information of the views A_k (k = 1 ... n; n = 40) generated with the pixels α as picture elements_ij used subpixels RGB of the color LC display, greatly enlarged and not drawn to scale,</dd><dt>Fig.42</dt><dd>another example of the structure of the filter elements β_why in a greatly enlarged and not to scale representation with the exclusive use of neutral filters, well suited for the spatial representation of a combination image according to Fig.41,</dd><dt>Fig.43</dt><dd>a further embodiment for a combination image, which takes into account n = 40 views,</dd><dt>Fig.44</dt><dd>the section of a filter array for the embodiment of Figure 43, wherein a filter element has approximately one fifth of the width of a picture element,</dd><dt>Fig.45</dt><dd>the predominantly visible for a viewer eye selection from the views A_k (k = 1..n) in the embodiment according to FIG. 43 and FIG.</dd><dt>Fig.46</dt><dd>an embodiment of a filter array with transparent opaque filters and colored wavelength filter elements β_whyin which the wavelength filter elements β_why about one fifth of the width of the associated picture elements α_ij to have; matching a combination image according to FIG.</dd><dt>Fig.47</dt><dd>another example of a combination picture,</dd><dt>Fig.48</dt><dd>another example of a wavelength filter array which is well suited for a spatial representation with a combination image according to Fig. 47,</dd><dt>Fig.49a-c</dt><dd>various examples to illustrate possible embodiments of filter elements β_why,</dd><dt>Fig.50</dt><dd>an embodiment of an inventive arrangement with a lying in the line of sight of a viewer in front of a picture display device wavelength filter array that can be moved laterally by a displacement device,</dd><dt>Fig.51</dt><dd>a schematic representation of the structure of an autostereoscopic image display device for use in an inventive arrangement,</dd><dt>Fig.52</dt><dd>an example of a possible at n = 40 possible structure of the wavelength filter array using only opaque and transparent wavelength filter elements β_why, well suited for the spatial representation of a combination image according to Fig.41.</dd></dl>

<u style="single">Detailed description of the drawings</u>

Embodiment for explaining the basic principle of the 3D representation according to the invention:

The exemplary embodiment, which initially serves to explain the basic principle of the invention, provides for the reproduction of the combination of partial information of the views A_k (k = 1 ... n) on picture elements α_ij as well as for generating the mask image by means of wavelength filter elements β_why in each case a currently commercially available color LCD display, such as <i>Sanyo LMU-TK 12A.</i> In this way, the arrangement according to the invention can be realized easily and inexpensively. However, this does not exclude that for the image reproduction as well as for the wavelength filtering any other conceivable embodiment is possible, provided that the basic conditions of the invention are met.

Of the various possibilities with regard to the arrangement of picture-representing raster of picture elements α_ij, Array of wavelength filter elements β_why and a planar illumination source, a variant is shown in Figure 1, in the viewing direction B of a viewer 1, first a color LC display 2 as bilddarstellendes grid and at a predetermined distance z behind a color LC display 3 as a wavelength filter Array are arranged. The color LC display 3 is connected to a planar illumination source 4 to form a structural unit.

In addition, the image-reproducing color LC display 2 with a drive circuit 5 and the wavelength-selecting color LCD display 3 with a drive circuit 6 are linked. Each of the two color LC displays 2,3 has separately controllable subpixels of the primary colors red (R), green (G) and blue (B). For better distinctness, the subpixels of the color LC display 2 are denoted below by R, G, B, and the subpixels of the color LC display 3 by R ', G', B 'denote the respective transparency wavelengths / wavelength ranges λ_b correspond.

The drive circuit 5 is designed such that, as described above, on the individual subpixels R, G, B partial information of the views A_k (k = 1 ... n) can be generated.

The drive circuit 6 is designed so that the individual subpixels R ', G', B 'for the respective fundamental wavelength red, green and blue can be switched with a transparency between 0% and 100%. In this case, the transparency with 0% would become an opaque wavelength filter element β_why correspond.

The distance z between the color LC display 2 and the color LC display 3 is 3.8 mm in this case, the subpixels R ', G', B 'of the color LC display 3 corresponding to the subpixels R, G, B of the color LC display 2, in that the propagation directions of the light emerging from the subpixels R ', G', B 'and passing through the subpixels R, G, B are within a viewing space 7, in which one or more observers 1 are located, meet in a variety of intersections. These intersections of the propagation directions correspond to observation positions from which the scene / object can be spatially perceived with one pair of eyes.

In this case, the distance z for the exemplary embodiment variant according to FIG. 1 was determined <maths id="math0007" num="(f3)"><math display="block"><mrow><mrow><mo>(</mo><mrow><mi mathvariant="normal">F</mi><mn>3</mn></mrow><mo>)</mo></mrow><mi> </mi><mfrac><mi>with</mi><mrow><msub><mi>s</mi><mi>p</mi></msub></mrow></mfrac><mo>=</mo><mfrac><mrow><msub><mi>d</mi><mi>a</mi></msub></mrow><mrow><msub><mi>p</mi><mi>d</mi></msub></mrow></mfrac></mrow></math><img file="EP1689162A2_D0007.tif" /></maths>

For s_p the average horizontal distance of the subpixels R ', G', B 'on the viewing direction downstream color LCD display 3 was assumed to be 100 μm. For the mean pupillary distance p_d was set 65mm. As mean viewing distance d_a was chosen 2.5m. This results in the distance z to be executed with 3.8 mm.

The array with the wavelength filter elements β is advantageous_whyif this is the raster of pixels α_ij is arranged in the viewing direction of the viewer, running as thin as possible. Conversely, if the grid of pixels α_ij upstream, this should be as thin as possible. Therefore, in FIG. 1, FIG. 8 and FIG. 10, the distance z between the mutually facing surfaces of the array or of the grid is entered and does not additionally include the thickness of the respective upstream assembly. As such as thin as possible assemblies, for example, printed films or thin color LC displays come into question.

The directions of propagation are in each case given by the area centers of the visible sections of the relevant subpixels R ', G', B 'and R, G, B, the beam paths propagating not only in one plane, but in many cases spatially distributed.

FIG. 2 shows an example of a mask image based on individual subpixels. R ', G', B 'of the color LC display 3 shown in a plan view of the display surface, the sake of clarity greatly enlarged and not to scale. The illustrated sub-areas correspond in each case to a subpixel, which in transparent control is translucent for light of the respective primary color red (R '), green (G') and blue (B '). S denotes the subpixels which are opaque. The faces are shown here simplified square; on the exact representation of the shape of the subpixels R ', G', B 'was deliberately omitted here.

For example, when creating a mask image with b_max = 4 three transparency wavelengths / wavelength ranges λ_one, λ₂, λ₃ given for R, G, B and another transparency wavelength range λ_fourwith which the visible light can be blocked completely, the result is the use of the coefficient matrix d_whywhich one according to the rule <maths id="math0008" num="(f4)"><math display="block"><mrow><mrow><mo>(</mo><mrow><mi mathvariant="normal">F</mi><mn>four</mn></mrow><mo>)</mo></mrow><mi> </mi><msub><mi>d</mi><mrow><mi>p</mi><mi>q</mi></mrow></msub><mo>=</mo><mstyle scriptlevel="+1"><mfrac><mrow><mi>p</mi><mo>-</mo><mn>one</mn><mo>-</mo><mrow><mo>(</mo><mrow><mi>p</mi><mi mathvariant="normal">against</mi><mn>3</mn></mrow><mo>)</mo></mrow></mrow><mi>q</mi></mfrac></mstyle><mi>d</mi><mrow><mo>(</mo><mrow><mrow><mo>(</mo><mrow><mi>p</mi><mo>+</mo><mi>q</mi></mrow><mo>)</mo></mrow><mi mathvariant="normal">against</mi><mn>eight</mn></mrow><mo>)</mo></mrow><mo>+</mo><mrow><mo>(</mo><mrow><mstyle scriptlevel="+1"><mfrac><mrow><mi>p</mi><mo>-</mo><mn>four</mn></mrow><mi>q</mi></mfrac></mstyle></mrow><mo>)</mo></mrow><mi>d</mi><mrow><mo>[</mo><mrow><mi>d</mi><mrow><mo>(</mo><mrow><mrow><mo>(</mo><mrow><mi>p</mi><mo>+</mo><mi>q</mi></mrow><mo>)</mo></mrow><mi mathvariant="normal">against</mi><mn>eight</mn></mrow><mo>)</mo></mrow></mrow><mo>]</mo></mrow></mrow></math><img file="EP1689162A2_D0008.tif" /></maths> one for the spatial representation of an object / scene on the basis of n = 8 views A_k (k = 1 ... n) well suited mask image.

2, the planar illumination source 4 is located behind the array shown in FIG. 2, that is to say below the plane of the drawing in FIG. 2. When the illumination source 4 is switched on, light of the respective primary colors goes red from the individual subpixels R ', G', B ' , green and blue off. The subpixels labeled S remain dark.

FIG. 3 shows - also not to scale - an example of the combination of partial information of different views A_k (k = 1 ... 8) in a plan view of the grid of the color LC display 2, according to the function already described <maths id="math0009" num="(f1)"><math display="block"><mrow><mrow><mo>(</mo><mrow><mi mathvariant="normal">F</mi><mn>one</mn></mrow><mo>)</mo></mrow><mi> </mi><mi>k</mi><mo>=</mo><mi>i</mi><mo>-</mo><msub><mi>c</mi><mrow><mi>i</mi><mi>j</mi></mrow></msub><mo>⋅</mo><mi>j</mi><mo>-</mo><mi>n</mi><mo>⋅</mo><mi>IntegerPart</mi><mrow><mo>[</mo><mrow><mfrac><mrow><mi>i</mi><mo>-</mo><msub><mi>c</mi><mrow><mi>i</mi><mi>j</mi></mrow></msub><mo>⋅</mo><mi>j</mi><mo>-</mo><mn>one</mn></mrow><mi>n</mi></mfrac></mrow><mo>]</mo></mrow><mo>,</mo></mrow></math><img file="EP1689162A2_D0009.tif" /></maths> has been generated, wherein c_ij = -1 = const. and n = 8 are selected.

Again, each square subarea corresponds to a subpixel R, G, B. The numbers 1 ... 8 = k given within the square subareas give the respective view A_k (k = 1 ... n), to which the on a subpixel or a pixel α_ij Part information displayed belongs. Thus, a partial information displayed on a subpixel designated k = 1 belongs to the view A_one, a partial information displayed on a subpixel designated k = 2 for the view A₂ etc. In the selected embodiment, therefore, eight views A are for spatial representation_one bis A_eight, preferably perspective views provided.

For reasons of clarity, it was, inter alia, omitted to represent the "black matrix", which is often incorporated for technical reasons in color LC displays.

Now imagine that the grid shown in Figure 3 is arranged upstream of the array shown in Figure 2 in the viewing direction, as shown in Figure 8, Thus, the light (FIG. 2) coming from a subpixel R 'of the primary color is directed through all the corresponding subpixels R of the grid (FIG. 3) into the viewing space 7 (which lies above the plane of the drawing), thereby leading to the partial information With, which are shown on the subpixels R and partial information of the views A_k (k = 1 ... n).

The mode of operation, which in this case is the basis of the realization of the spatial impression, will now be explained in detail with reference to FIG. 4 to FIG. 7, an arrangement according to FIG.

To simplify matters, only red picture elements α are used in this regard_ij or red wavelength filters β_why considered. This means that in Fig.4 only the red wavelength filter β_why 2 are shown; 4 shows the structure of a mask image with wavelength filter elements R '. Accordingly, Fig.5 shows only the red pixels α_ij from Fig.3. The numbers entered in the columns of the illustration in FIG. 5 correspond to the consecutive number k of the view A._k(k = 1 ... 8), from which the on this picture element α_ij or subpixel R to be displayed partial information to a combination image from the views A_k (k = 1 ... 8). This exemplary explanation is transferable to blue and green in an equivalent manner.

The illustrations in FIGS. 4 and 5 are not drawn to scale, and the mask image is shown somewhat enlarged. This should reflect the fact that, for example, when using a mask image according to Figure 2, in which the wavelength filter elements β_why actually have the same dimensions as the picture elements α_ij in Figure 3, the mask image a viewer due to the closer position in the viewing direction appears slightly larger than the grid with the pixels α_ij,

If you now - mentally - this slightly enlarged mask image of Figure 4 directly to the combination image of Figure 5, the visible for different eye positions picture elements are α_ij or parts thereof recognizable.

This is illustrated in FIGS. 6 and 7 by way of example and not to scale for two mask images-each intended for different eye positions. It can be seen that, for example, from the eye position which is assigned to FIG. 6, primarily image elements .alpha_ij (or portions thereof) of Views A₇ and A_eight are perceptible. According to Figure 7, however, are from a position in which the other eye of the same observer, mainly pixels α_ij (or parts thereof) from views A_four and A_five visible.

This is intended to clarify only the basic principle of the method according to the invention. With the diversity resulting from the areal arrangement of picture elements α_ij results, then results in the three-dimensional perception: both eyes see from the viewing positions pixels α_ij or partial information of predominantly different views A_k (k = 1 ... n), whereby the proportion of the partial information perceptible for each eye is decisive for the three-dimensional perception.

Deviating from the basic configuration according to Figure 1 further embodiments of the invention are possible. For example, as shown in FIG. 8, provision may be made for a wavelength filter array 8 to be arranged instead of the color LC display 3 (in FIG. 1), although in a manner similar to the color LC display 3 structured wavelength filter elements β_why However, for example, which are not changeable in terms of their wavelength selectivity. Each of these wavelength filter elements β_why is the selectivity according to the primary colors red, green or blue or opaque or other transparency wavelength / wavelength range λ_b assigned unchangeable, which is why the drive circuit is superfluous here.

FIG. 9 shows (not to scale) a section through such an arrangement shown in FIG. 8, the circumstances according to FIGS. 1 to 3 being taken as a basis. The representation is also here not to scale, but can nevertheless serve to explain: In Figure 9, for example, sees the right eye r each about half a pixel α_ij with partial information from the views A₃ (in this case R) and A_eight (in this case B) and a very small part of a picture element α_ij with partial information from view A₆(in this case G). The left eye, on the other hand, takes about half a pixel each_ij with partial information from the views A_four (in this case R) and A₇ (in this case G) and in each case a very small part of a picture element α_ij with partial information from the views A_one and A₂ (in this case B) true.

In a further embodiment variant, which differs from Fig.1 and Fig.8, it can be provided in Fig.10 that from the position of the observer 1 in the viewing direction, first the wavelength filter array 8 and at the distance z behind the imaging color LC Display 2 are positioned, the latter being connected to the planar illumination 4 to form a structural unit. Hereby basically the same effect is achieved, namely the propagation directions of the light coming from the subpixels R, G, B of the color LC display 2 through the corresponding wavelength filter elements R ', G', B 'of the wavelength filter array 8 intersect in FIG Viewing space 7 in a plurality of viewing positions from which the object shown is spatially perceptible.

It should again be noted that the subject matter of the invention is not limited to the arrangements shown here by way of example, but that all arrangements are detected by the invention, in which the propagation directions by a wavelength-selective structure, the above-mentioned rule is generated in conjunction with a - preferably colored - grid of pixels α_ij be determined.

How to reduce or The avoidance of moiré effects as a significant advantage of the invention is to be explained below, for example, with reference to the arrangement shown in Figure 1, wherein the combination image of Figure 3 and the mask image of Figure 2 are based. It is well known that moiré fringes result from superposition of periodic patterns in the direction perpendicular to the angle bisector of the included angle of two preferred directions of the various said patterns.

In the case of a commercially available color LC display, the subpixels are arranged in columns, with exactly every third column containing only red subpixels. Since in the selected embodiment both for the reproduction of the views A_k (k = 1... n) and also commercially available color LC displays are used for the generation of the mask image, one of the directions to be considered for the determination of the bisecting line is therefore always the vertical one. The second direction is obtained by connecting a selected red subpixel on the mask image with another through a straight line. (Reference points are always the lower left corners of the subpixels).

In Figure 11 this is exemplified for such a straight line. The resulting bisecting line is shown with a dashed line, while the bisector on the bisector indicates the propagation direction of the associated moiré strip. For all other connecting lines or directions of two red wavelength filter elements β shown in FIG_why of the mask image can thus be determined analogously to the corresponding propagation directions for moiré strips. In addition, there are a variety of other relevant directions that are not apparent because of the detailed representation of the mask image here.

The perceptibility of the moire fringes is directly related to the spatial frequency of the red wavelength filter elements β_why on the connecting line. The smaller the distance of the red wavelength filter elements β_why on the line, ie the higher the spatial frequency of the red wavelength filter elements β_why is, the more clearly the corresponding moiré stripes are perceptible.

Since, however, very many moiré stripes develop in an arrangement according to FIG. 1 or FIG. 2 at the same time, no dominant moiré preferential direction is to be perceived by a viewer.

All the considerations presented here apply equally to the green and blue picture elements α_ij or wavelength filter elements β_why, which also reduces the moiré effects there.

The reasons for the improved text readability - compared with known black and white barrier methods - will be explained below with reference to Figure 12 and Figure 13. For example, Figure 12 shows the relationships in a black-and-white barrier known in the art when a visible light transparent column T is followed by three opaque columns S, which is a barrier to a four-view system.

If wavelength-dependent mask image structures are used completely without opaque areas, as shown for example in FIG. 3, and if two text mask structures according to FIG. 12 and FIG. 13 are overlaid with ordinary text, then only one part is under the black-and-white barrier on the average a quarter of the displayed text area visible. On the other hand, with the RGB barrier of Figure 13, the text is visible under each filter. This greatly facilitates text readability.

Embodiments of the arrangement according to the invention will now be explained in more detail below when equipped with means for 2D-3D switching.

In a first such exemplary embodiment, which is shown in FIG. 14 and in which the three-dimensional (autostereoscopic) representation can be switched to a two-dimensional representation, those on the image elements α originate_ij reproduced image information from perspective views of the scenes or objects to be displayed.

In FIG. 14, in the viewing direction of an observer 1, an image reproduction device in the form of a currently commercially available color LC display 2, such as for example <i>Sanyo LMU-TK 12A,</i> and at a distance z behind a filter assembly 9 with a filter array 10 is arranged. Behind the filter assembly 9 is here again a planar illumination source 4, which emits white light.

The filter array 10 consists in this case of a grid-like combination of wavelength filter elements 1 1.1 and linear polarization filter elements 11 .2. In addition to this filter array 10, the filter arrangement 9 comprises an optical medium 12 with which the direction of polarization of the incident linearly polarized light can be rotated during the passage through the filter arrangement 9, as well as a planar linear polarization filter 13. The linear polarizing filter 13 is positioned between the color LC display 2 and the optical medium 12. The forward direction of the linear polarizing filter 13 corresponds to the forward direction of an existing, but not shown in the drawing, the lighting side polarization filter of the color LC display. 2

The color LC display 2 also has separately controllable subpixels of the primary colors red (R), green (G) and blue (B) and is linked to a drive circuit 5. For better distinctness, the subpixels of the color LC display 2 are again denoted by R, G, B, whereas the wavelength filter elements 11.1 are denoted by R ', G', B 'as a function of their transparency. The wavelength filter elements 11.1 are transparent to light regardless of the polarization direction.

The drive circuit 5 is, as in the previously explained embodiments for generating partial information of the views A._k (k = 1 ... n) formed on the individual subpixels R, G, B of the color LC display 2.

If the 3D mode is activated-as will be explained in more detail below-the propagation directions of the light coming from the wavelength filter elements 11.1 of the filter arrangement 9 and radiating through the corresponding subpixels R, G, B of the color LC display 2 intersect the viewing space 7 in a plurality of viewing positions, from which the displayed object or the scene is spatially perceptible.

The distance z between the color LC display 2 and the filter array 10 is here 2.3 mm. This measure results from (F3), if for s_p the mean distance between the wavelength filter elements 11.1 on the filter array 10 with each other is assumed to be 100 μm. In this case, the wavelength filter elements 11.1 in their extension perpendicular to the viewing direction are designed to be approximately as wide as the subpixels of the color LC display 2 used. For the mean pupil distance p_d was set 65 mm. As mean viewing distance d_a was chosen 1.5 m.

The combination of partial information of different views A_k (k = 1 ... 8) on the color LC display 2 here again corresponds to the example of Figure 3. Furthermore, the filter array 10 is based on the example of the mask image according to FIG. The combination of partial information and the mask image are here also in the manner already described according to the functions (F1) or (F2) generated, and the mode of operation, which is based on the conclusion of the autostereoscopic impression, corresponds to the above with reference to Figure 4 to Figure 7 and Figure 9 given explanation.

A second embodiment of the inventive arrangement with means for 2D-3D switching is shown in Fig15. This corresponds in terms of the modules used substantially to the first embodiment of FIG. 14, but now is the filter assembly 9 with the filter array 10, which in turn includes both wavelength filter elements 11.1 and Linearpolarisationsfilterelementen 11.2, seen from the position of the viewer 1 at a distance z before the imaging color LC display 2. Furthermore, in the exemplary embodiment according to FIG. 15, the filter array 10 is no longer located directly in front of the light source 4.

In FIG. 15, the color LC display 2 is connected to the planar illumination device 4 and the linear polarization filter 13 to form a structural unit. If the 3D mode is now activated-as will be explained in more detail below-the directions of propagation of the light coming from the subpixels R, G, B of the color LC display 2 and radiating through the corresponding wavelength filter elements 11.1 of the filter arrangement 9 intersect in the viewing space 7 in a plurality of viewing positions, from which the illustrated object or the scene is spatially perceptible.

In Fig. 14 and Fig. 15, the linear polarizing filter elements 11.2 are represented by horizontal lines so as to symbolize the polarization direction. It can be seen that the polarization direction is the same for all linear polarization filter elements 11.2. The linear polarizing filter elements 11.2 can be transparent in their effect either opaque or even in the entire range of visible light; In addition, it is also possible to limit the polarization-dependent transparency to specific wavelength ranges, eg also to R ', B', G '.

The arrangement of the wavelength filter elements 11.1 and the Linearpolarisationsfilterelemente 11.2 in the direction of the observer corresponds in both embodiments of FIG. 14 and FIG. 15 of the greatly enlarged and not to scale representation in Figure 2. The wavelength filter elements 11.1 are recognizable in FIG. 2 on the basis of the designations R ', B', G ', whereas the linear polarization filter elements 11.2 are denoted by S.

The filter array 10 is preferably in the form of a thin plastic film or plastic plate, which are structured in the manner described.

The controllable optical medium 12, which allows a defined rotation of the polarization direction of the passing linear polarized light, cooperates with the filter array 10 and the Linearpolarisationsfilter 13 to - depending on the rotation - the light passage through the filter assembly 9 in the region of Linearpolarisationsfilterelemente 11.2 either enable or but not possible.

To trigger the rotation, a drive device 14 is provided which, for example, by applying a control signal to the optical medium 12 allows a change in the polarization direction of the light on the way from the light entrance side to the light exit side.

In this regard, the optical medium 12 has, for example, liquid crystals. In the embodiment of Figure 14 for this purpose, a conventional LC display (or. an LC panel) was used in which any existing color filters and polarizing filters were missing or removed. However, an LC display can also be used in which one side still a linear polarization filter is provided, which then takes over the function of the above-explained linear polarization filter 13. The switching of the optical medium 12 takes place in this case favorably via the drive means 14 of the correspondingly formed LC display. By way of example, a white or black screen content can serve as a drive signal internally, which then eg corresponds to two crossed effective polarization rotation directions of the liquid crystals. As optical medium 12 for rotation of the polarization direction are, inter alia LC displays of type Philips 150B or Sanyo LMU-TK 12A. These results in the further simplification that not every single liquid crystal element must be driven separately, but that all liquid crystal elements can respond to one or a few control modules.

In contrast, in the embodiment according to FIG. 15, an image reproduction device is provided which emits linearly polarized or unpolarized light. It is formed here by way of example by the color LC display 2 and the underlying illumination source 4. In the exemplary use of a color LC display 2 described here, the areally extended linear polarization filter 13 is already functionally integrated into the color LC display 2, so that the color LC display 2 emits linearly polarized light. For other types of displays 2, which emit unpolarized light, such as Plasma screens, the linear polarizing filter 13, however, represents a separate module to be added.

Is done in the optical medium 12, which in both cases is arranged between the linear polarizing filter 13 and the filter array 10, no rotation of the polarization direction and intersect the polarization direction of the areally extended linear polarization filter 13 with the polarization direction of the linear polarization filter elements 11.2 at an angle of 90 °, Thus, a passage of light in the region of the linear polarization filter elements 11.2 of the filter arrangement 9 is largely prevented. In this case, the filter arrangement 9 then has a structuring suitable for the autostereoscopic, three-dimensional representation.

To switch to the two-dimensional representation of the optical medium 12 is actuated via the drive means 14, whereupon the polarization direction of the incident light is rotated by a defined angle, in such a way that it can pass through the Linearpolarisationsfilterelemente 11.2. The originally strong restriction of the propagation directions of the light is thus significantly reduced. In addition, there is a higher average light transmission. For the viewer in this case more image information is visible, whereby the image resolution increases. In particular, the readability of texts can be improved. In the ideal case, ie with a parallel orientation of the polarization directions on the light exit side of the optical medium 12 and the linear polarization filter elements 11.2, the latter act as 100% transmitting analyzers. However, a strict parallelism is not mandatory, since even at small angles of intersection of the polarization directions to about 15 °, which are still considered to be substantially parallel, a light transmission of about 90 percent is achieved. This is sufficient for a good text recognition as well as a high-resolution 2D image representation in each case.

In the embodiment shown in Fig.15, the polarization directions of the linear polarizing filter 13 and the linear polarizing filter elements 11.2 are arranged such that when the optical medium 1 2 is turned off, the device is in the 3D mode. By a different orientation, for example, the linear polarization filter 13, however, a reverse operation is possible in which prevails in the off state of the optical medium 12, the 2D mode, so that for the 3D operation, the optical medium 12 is to be activated.

The polarization rotation of the optical medium 12 can, as explained above, be generated in different ways. In a variant, as a switchable optical medium 12, a longitudinal Pockels cell with a corresponding control can be used. In such a cell, the natural optical axis of a crystal of which it consists essentially is aligned parallel to a switchable electric field which is modulatable in the longitudinal direction. The fast and slow optical axes formed in the crystal when the field is turned on must be at an angle of 45 ° to the plane of oscillation of the linearly polarized incident light, which is achieved here by a corresponding orientation. The Pockels cell consists for example of lithium niobate (LiNbO₃) or potassium phosphate (KH₂PO_four). If the so-called half-wave voltage U is applied to the Pockels cell, the polarization direction of the incident linear-polarized light is rotated by 90 °. The half-wave voltage is calculated according to the equation<maths id="math0010" num="(f5)"><math display="block"><mrow><mrow><mo>(</mo><mrow><mi mathvariant="normal">F</mi><mn>five</mn></mrow><mo>)</mo></mrow><mi mathvariant="normal"> </mi><mi mathvariant="normal">U</mi><mo>=</mo><mrow><mrow><msub><mrow><mi mathvariant="normal">λ</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow><mo>/</mo><mrow><mn>2</mn><msup><mrow><msub><mrow><mi mathvariant="normal">rn</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow><mrow><mn>3</mn></mrow></msup></mrow></mrow><mo>.</mo></mrow></math><img file="EP1689162A2_D0010.tif" /></maths>

Here is λ₀ the base wavelength for which the half-wave voltage is to be calculated, r the tensor element of the linear electro-optic constant indicating the component used in the Pockels cell, and n_O the refractive index of the corresponding crystal. For example, for λ₀ = 555 nm (green light) for LiNbO₃ the half-wave voltage U = 747 V and for KH₂PO_four U = 7327 V.

Deviations from the exact polarization direction angle 90 ° for the wavelengths different from 555 nm are not detrimental, since the linear polarization filter elements 11.2 and the linear polarization filter 13, like all polarizer-analyzer pairs, have an intensity transmission characteristic proportional to the square of the cosine of the angle of rotation. This means that the angle of rotation of the polarization direction of the filter array 10 or the linear polarizing filter 13 directed light in the range of 75 ° to 105 ° always for a more than 90% igen passage of the light through the filter assembly 9 ensures.

In a separate embodiment variant, instead of the structure of the filter array 10 shown in FIG. 2, it is also possible to use a structure which, in addition to the individual elements R ', B', G 'and S, always has transparent elements, ie polarization direction independent elements T. A concrete arrangement of these elements for the purpose of a switching effect clearly perceptible in cooperation with the optical medium 12 and the linear polarizing filter 13 is shown by way of example in FIG.

In a third embodiment of the 2D-3D switching, which is shown in Fig.17, as a means for switching a lens 1 5 is provided. The arrangement shown here again has a color LC display 2 as image display device, a filter arrangement 9 and an illumination source 4. From the viewing position, the color LC display 2 lies in front of the filter arrangement 9.

The filter assembly 9 comprises a static filter array 10 of the type already described above. In addition, the filter assembly 9 comprises a flat lens 15, which is switchable by means of a drive means 16 electronically between a transparent state and a scattering, translucent state. This diffusion plate 15 is positioned between the filter array 10 and the color LC display 2. Such lenses with dimensions of up to 50 inches in diagonal and larger are available, for example, as Privalite® glasses from VEGLA, Aachen, Germany. These glasses are based on liquid crystals that are milky in the tension-free state, ie On the other hand, when an electrical voltage is applied, they become substantially transparent.

In the transparent state, the illumination structured by the filter array 10 acts as a basis for the 3D operating mode, ie the diffuser 1 5 has no functionally significant influence on the passing light. If, however, the lens 15 is switched to the scattering state, the structuring of the illumination is substantially canceled. This has the consequence that the translucent image display device, in this case the color LC display 2, is largely homogeneously illuminated. Thus, conventional two-dimensional image contents can be displayed in the 2D mode without being influenced by the filter array 10.

In a further exemplary embodiment for 3D-2D switching, in particular in the structure of the arrangement according to the invention shown in FIGS. 8 and 10, a filter arrangement may be used as the means for 2D-3D switching instead of the wavelength filter array 8, which is described below to be explained in more detail with reference to Fig.18 to Fig.23.

This filter arrangement includes two at assembly example as a thin film arrays of static, ie with regard to their optical properties, temporally invariable wavelength filter elements. Both wavelength filter arrays are composed of a plurality of similar basic elements, one of which is shown in Fig.18 and Fig.19. These basic elements differ in terms of structuring with individual wavelength filter elements R ', G', B 'or with elements T, which are transparent in the entire range of visible light (cf. Fig.19).

FIG. 20 shows a detail of a first wavelength filter array which is composed exclusively of similar basic elements, as shown in FIG. This wavelength filter array has no transparent elements T.

FIG. 21 shows a section of a second wavelength filter array which is composed exclusively of basic elements, as shown in FIG. In addition to wavelength filter elements R ', G'B', this wavelength filter array also has transparent elements T.

When superimposing both wavelength filter arrays from FIG. 20 and FIG. 21, so that the light must pass through both wavelength filter arrays one after the other, the wavelength filter elements R ', G'B' or "R" result in a first orientation. the elements T to each other the total wavelength filter array shown in Figure 22, in which only in the region of the transparent elements T (on the wavelength filter array of Fig.21) by the wavelength filter elements R ', G'B' on the wavelength filter. Array according to Fig.20) certain filter effect is achieved. At all other locations where wavelength filter elements R ', G'B' of both wavelength filter arrays overlap, the summing wavelength filter array is opaque, ie intransparent. The opaque raster subsections of the total wavelength filter array are labeled S in FIG.

As a filter arrangement, the summing wavelength filter array effects a specification of the propagation directions of the light emitted by the color LC display 2 in the manner described above, whereby a realistic, three-dimensional perception is possible. By way of example, predominantly information from a first group of views A is displayed at a first observation location_four bis A_five and at a second exemplary observation location at eye relief from the first location predominantly information of the second group of views A₇ bis A_eight perceived.

After shifting the two superimposed wavelength filter array from FIG. 20 and FIG. 21 by three raster positions in the horizontal direction parallel to one another, the summary wavelength filter array shown in FIG. 23 results. As can be seen from Figure 23, this results in a very high light transmission, since only one of the total twenty-four grid sections of a primitive is opaque. Due to the resulting high transparency of the summary wavelength filter array according to FIG. 23, the three-dimensional perception impression existing in the previous first position is canceled, so that the image information displayed on the color LC display 2 can now be viewed in two dimensions.

The parallel displacement of the two wavelength filter array according to FIG. 20 and FIG. 21 relative to one another takes place in a mechanical manner, for example by a piezoelectric actuator, with which very small displacement steps of the order of magnitude of the grid width or grid height of the wavelength filter array can be realized. Instead of a piezo actuator, a stepper motor can also be used.

In a modification, it is also possible to superimpose more than two wavelength filter array and move separately against each other, but care should be taken that the two above-mentioned positions arise.

It is immediately apparent that for this purpose the positioning of the wavelength filter elements R ', G'B' and the transparent elements T must be matched to each other, so that with the parallel displacement a first position with a higher degree of order to produce a 3D impression and a second Position with a low degree of order, but with increased transparency for 2D representation result.

With the first and second wavelength filter array shown in FIG. 20 and FIG. 21, a good 3D impression and in the second position a good 20 impression can be obtained with parallel displacement by three raster subsections in the first position. However, the invention is not limited to the structuring of the wavelength filter array described here, but it can be based on the above consideration or in an iterative way still further arrangement patterns are generated.

For example, the filter arrangement may also be formed by the superposition of seven wavelength filter arrays whose individual wavelength filter elements are either opaque or transparent throughout the range of visible light. An example of such a wavelength filter array is shown in FIG. In the case of a superimposition of seven such wavelength filter arrays with an offset of one raster subsection each, the summation wavelength filter array shown in FIG. 25 results.

At the same time, FIG. 25 represents the first position of this filter arrangement for the autostereoscopic mode. By switching the filter arrangement by means of one of the abovementioned mechanical devices, a second position is achieved in which the total wavelength filter array is largely transparent, that is to say that all the opaque raster subsections lie one behind the other in the viewing direction. This results in a summary wavelength filter array whose structuring corresponds to Fig. 24 and which has a high transparency, so that the images shown on the color LC display 2 are perceived two-dimensionally.

To improve the filtering effect during 3D operation, the opaque filter elements, which in the first position according to FIG. 25 do not adjoin the still transparent diagonal stripe, are for example about 1.3 times wider than the remaining opaque filter elements. This results in the first position, an overlap of the opaque filter elements, which ensures that when viewed at an oblique angle, that is not perpendicular to the bilddarstellende surface, only by the desired, still transparent grid sections of the filter assembly on the bilddarstellende grid the color LC display 2 is looked.

So far, for the sake of simplicity, wavelength filter elements have been described which are transparent in the red, green and blue light or even in the entire range of visible light. However, the invention also deviates from the possibility of using other transparency wavelength ranges, provided that they are suitable for the formation of static, passive filter arrays. Moreover, the transparency wavelength ranges need not be limited to the range of visible light.

Under certain circumstances, for a viewer either a two-dimensional, two-dimensional, three-dimensional or a two-dimensional, partially three-dimensional representation of a scene or an object is desired for a viewer. In this regard, the further embodiments described below for 3D-2D switching are advantageous.

FIG. 26 firstly shows the basic structure of the arrangement according to the invention with the option of optionally displaying two or three dimensions of images of a scene or an object. From viewing direction B of a viewer (resp. several viewers) following one another are symbolically drawn here: a picture display device 18, which consists of a multitude of translucent picture elements, on which image information from several perspective views of the scene / the object can be displayed; a first planlight source 19 associated with the lighting device of the arrangement; a wavelength filter array 20, consisting of a plurality of translucent in predetermined wavelength ranges filter elements and belonging to the illumination device of the arrangement second planlight source 21st

The wavelength filter array 20 consists of a plurality of filter elements approximately 0.99 mm (width) and 0.297 mm (height). These dimensions are matched to a color LC display "Batron BT 63212", which is to serve as an example image display device 18 here. The distance between image display device 18 and wavelength filter array 20 is about 2 mm in the example chosen.

The drive circuit 22 has the function of displaying on the image display device 18 combination images from several views, in particular from several perspective views of the scene to be displayed or of the object. These combination images can be still images or, if appropriate, also moving images which change in predetermined short time cycles. In addition, the drive circuit 22 causes the switching on / off of the two planlight sources 19 and 21, which are assigned for this purpose each separately controllable on / off switch (not shown in the drawing).

Depending on the specification by the drive circuit 22, it is possible to switch between a plurality of different operating modes. in which the illumination light is used either only for the purpose of two-dimensional representation only by the picture elements of the image display device 18, However, not through filter elements of the wavelength filter array 20 passes through to the viewer or for the sake of three-dimensional representation by the filter elements of the wavelength filter array 20 and subsequently also passes through the picture elements of the image display device 18 through to the viewer.

3 shows, by way of example, a greatly enlarged detail of the image structure of the image display device 18 with the multiplicity of image elements. Each of the subpixels shown in the form of squares in FIG. 3 always has exactly the same position i, j within the image grid of rows and columns with respect to a perspective view. The combination picture to be generated is based on eight perspective views, ie the image information to be reproduced on the individual picture elements is obtained from eight perspective views and combined into an overall picture which corresponds in its areal extent to the picture display device. The numbers 1 to 8 entered in the picture elements each indicate one of the eight perspective views from which the respective image information originates. The substantially enlarged grid of picture elements has a total of 1024 columns and 768 lines, for example, according to the color LC display used.

In order to ensure that the observer always simultaneously sees image information from different views, ie from different image channels, the wavelength filter array 20 is structured as shown by way of example in dependence on the individual image elements of the image reproduction device 18, which preferably have pixel or subpixel size in FIG. 2 by means of a likewise greatly enlarged detail from the structure of the wavelength filter array 20.

While in Fig. 3 each square corresponds to one picture element in pixel or sub-pixel size, in Fig. 2 each square should correspond to a filter element. The filter elements marked with R 'are transparent only in the area of ​​the red light, the filter elements marked with G' only in the area of ​​the green light and the filter elements marked with B 'only in the area of ​​the blue light. S denotes filter elements which are opaque (in the visible spectral range). The screening of the filter elements and the picture elements are proportional or identical with respect to their dimensions.

Fig. 27 shows a basic structure of the arrangement according to the invention, in which deviating from the structure of Fig. 26 not only the option for either two- or three-dimensional representation of images of a scene or an object, but also the possibility is given, image sections to be able to play two- or three-dimensional, depending on your choice.

Here, between the planlight source 21 and the wavelength filter array 20, a shutter 23 is arranged, which consists of a plurality of individually controllable shutter elements, wherein depending on the number of controlled shutter elements, the path of the illumination light generated by the second planlight source 21 by a larger or smaller number can be interrupted or released by filter elements. In the following, it should be assumed that controlled shutter elements "open" the light path, while non-activated shutter elements "block" the light path.

In operation of the arrangement, in a first mode of operation, only the first planlight source 19 is turned on for two-dimensional display, and illuminating light passes only through the image display device 18 but not through the wavelength filter array 20 to the viewer. In a second mode of operation for the purpose of three-dimensional representation, only the second planlight illumination source 21 is switched on so that illumination light always passes through the wavelength filter array 20 and the image display device 18 to the viewer.

In a third operating mode, both planlight sources 19 and 21 are switched on, and a predetermined number of shutter elements is driven, so that the illuminating light reaches the observer in areas of the controlled shutter elements, thus releasing the light path, both through the filter elements and through the associated picture elements, while the illumination light in areas of the non-driven (the light path "blocking") shutter elements only passes through the image display device 18 to the viewer.

As a result, the scene / article is two-dimensionally perceivable in the regions of the non-controlled shutter elements, whereas it is perceivable three-dimensionally in the regions of the controlled shutter elements. A prerequisite for this, however, is that the plan lighting 21 provides a significantly higher luminance per unit area, as the planlight source 19, which can be achieved for example by means of dimmers.

In Fig.28, the plano lighting source 19 is shown in an embodiment that includes a light source 24 and a planar light guide 25. The light guide 25 is bounded by two opposing large surfaces 25.1 and 25.2 and by circumferential narrow surfaces 25.3 and 25.4, of which in Fig.28 only the sectional views can be seen. The two other narrow surfaces delimiting the light guide can be imagined parallel below and above the plane of the drawing.

The light source 24 is, for example, a rod-shaped lamp whose longitudinal extent is aligned perpendicular to the plane of the drawing. It is positioned so that the radiation emanating from it is coupled into the light guide 25 through the narrow surface 25.3. The coupled radiation becomes a proportion L_one reflected back and forth within the light guide and to a proportion L₂ emitted as useful light over the large area 25.1. In a separate case, the coupling surface opposite the narrow surface 25.4 may be designed to be reflective, so that radiation directed thereto is reflected back into the light guide.

In a preferred embodiment, the light source 24 may also be assigned a reflector 26, which contributes to increasing the intensity of the radiation directed onto the narrow surface 25.3 and coupled into the light guide 25.

In order to be able to influence the light density distribution over the radiating large area 25.1 of time to a predetermined extent, according to the invention on the radiating large area 25.1 opposite large area 25.2 a total reflection interfering coating 27 is provided, which consists of individual particles and their Störvermögen on the areal extent of Large area 25.2 is inhomogeneous between two limits. The limit values ​​of the interference power are determined by the density d of the coating 27, the density d being a measure of the mean distance between the particles per unit area.

FIG. 29 shows an example of how the density d of the coating 27 and thus its disturbance capability can be structured over the large area 25.2. In the drawing, the stripes are shown very wide to explain the principle. The stripe width is preferably much smaller in the physical version. The large area 25.2 is shown here perpendicular to the viewing direction B.

The different density d over the large area 25.2 is symbolized by hatching with different spacing of the hatching lines. It is assumed that the areas with larger distances between the hatching lines indicate a lower density d and thus a lower disturbing power, while the areas with smaller distances between the hatching lines indicate a greater density d and a more marked disturbance of the coating 27.

From Fig.29 it can be seen with reference to Fig. 28 that near the narrow surface 25.3, through which the light is coupled into the optical fiber 25, the density d or the disturbance low, with increasing distance x from this narrow surface 25.3 but progressively from Area section to surface portion is increasingly stronger.

This has the consequence that in the vicinity of the narrow surface 25.3 due to the lowest density d, the total reflection is the least disturbed, but still due to the there still high light intensity, a proportion L₂ the luminous flux exits from the large area 25.1, which is just as large as the luminous flux passing through the large area 25.1 at a greater distance x from the narrow area 25.3, since the light intensity decreases with increasing distance x but more light due to the increasing disturbance of the total reflection radiating large area 25.1 is decoupled.

In other words, as the distance x from the narrow surface 25.3 increases, the light intensity decreases, but the interference capability of the coating 27 increases, which, with a corresponding design of the density d, causes the light to radiate with almost the same intensity over the entire large area 25.1 becomes.

30 shows an embodiment in which the radiation emanating from a further light source 28 is additionally coupled into the light guide 25 through the narrow surface 25.4. In order to achieve a homogenization of the light emission over the large area 25.1 in one embodiment, the second large area 25.2 is to be provided with a coating 27, whose disturbance in this case starts from both narrow areas 25.3 and 25.4 towards the center of the light guide 25 is increasingly developed to a common maximum. This is shown with reference to FIG.

In this way, it is achieved that with increasing distances x of the narrow surfaces 25.3 and 25.4 through the coating 27, the total reflection from surface section to surface section disturbed more and so care is taken that despite the center of the area down to decreasing light intensity still about the same amount of light through the large area 25.1 is emitted as useful light as near the side surfaces 25.3 and 25.4.

The existing of a plurality of individual particles coating 27 can be realized by different materials. Thus, it is conceivable, for example, that particles with higher and particles with a lower level of interference are provided and these two types of particles are applied to the large area 25.2 in a predetermined quantity ratio. Here, in areas in which the total reflection is to be disturbed more strongly, particles with higher Störvermögen and in areas where the total reflection is to be disturbed less strongly, the particles with lower Störvermögen. For example, the higher impurity particles may be dull silver particles and the lower impurity particles may be shiny silver particles. These can be applied by means of printing processes, and it is advantageous if the shiny silver particles are applied in a first printing operation and the dull silver particles are applied in a second printing process.

When using these coatings for a three-dimensional representation, for example, according to FIG. 26 and FIG. 27, it is advantageous if some regular patterns are left in the coating during printing, preferably non-opaque wavelength filter elements being arranged at the locations of the recesses.

An alternative embodiment for this purpose, which can be produced in a technologically simple manner, provides a coating 27 consisting of a lacquer. In this case, the local resist density is one equivalent to the disturbance at a particular location. If, for example, the resist density is defined with the function d = f (x), then x is the measure of the distance from the narrow face 25.3 and d is a measure of the density with the limit values ​​d = 0 and d = 1, where 1 is the Disturbance at maximum paint density and 0 indicate the disturbance in the absence of paint coat. For example, in <maths id="math0011" num=""><math display="block"><mrow><mi mathvariant="normal">d</mi><mo>=</mo><mi mathvariant="normal">f</mi><mrow><mo>(</mo><mi mathvariant="normal">x</mi><mo>)</mo></mrow><mo>=</mo><msub><mi mathvariant="normal">a</mi><mn>3</mn></msub><mo>⋅</mo><msup><mi mathvariant="normal">x</mi><mn>3</mn></msup><mo>+</mo><msub><mi mathvariant="normal">a</mi><mn>2</mn></msub><mo>⋅</mo><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup><mo>+</mo><msub><mi mathvariant="normal">a</mi><mn>one</mn></msub><mo>⋅</mo><mi mathvariant="normal">x</mi><mo>+</mo><msub><mi mathvariant="normal">a</mi><mn>0</mn></msub></mrow></math><img file="EP1689162A2_D0011.tif" /></maths> the parameters a₀, a_one, a₂ and a₃ selectable. As advantageous parameter sets have proven in connection with the arrangement of Fig.28<ol id="ol0001" compact="compact" ol-style=""><li>(1) a₀= 0; A_one= 0.5; a₂= 2; a₃= -0.5;</li><li>(2) a₀ = 0; a_one = 0; a₂ = 1; a₃ = 0;</li><li>(3) a₀= 0; A_one= 0.5, a₂= -0.5; a₃= 1 For the arrangement of Fig.30 can be given advantageous</li><li>(4) a₀ = 0, a_one = 4, a₂ = -4 and a₃ = 0</li></ol>

In FIGS. 32 to 31, the density distribution as a function of the distance x is shown for the parameter sets (1) to (4). The parameters are basically freely selectable. However, it should be noted that the function d = f (x) in the domain [x_me, x _Max] Returns values ​​with 0 ≤ d ≤ 1. The values ​​x describe_me and x_Max trivially, the horizontal extent of the large area to be painted 25.2.

Based on this, in each case the value x is shown in FIGS. 32 to 35_me = 0 the position of the narrow surface 25.3 and the value x_Max = 1 assigned to the position of the narrow surface 25.4. This is the lowest density d_me = 0 at x_me = 0, ie always in the narrow area 25.3 or 25.4, is coupled into the light. The maximum density d_Max= 1 is always present at the greatest distance from the narrow surface 25.3 or 25.4, into which light is coupled. In FIG. 32 to FIG. 34, only the narrow surface 25.3 is in each case, so here lies the density d_me= 0 only at x_me = 0. In Fig. 35 the light coupling takes place in both narrow areas 25.3 and 25.4; therefore here lies the density d_me = 0 at x_me = 0 and at x_Max = 1, the density d_Max = 1 on the other hand at the place x = 0.5.

If light sources 24, 28 are used which emit light of inhomogeneous intensity in the direction y (see FIGS. 29 and 31), it can be provided according to the invention to vary the density d not only in direction x but also in direction y , whereby the density function is then given the form d = f (x, y).

This ensures that within the light guide 25 in places with lower light intensity, the large area 25.2 has a denser coating 27, wherein the total reflection is more disturbed there and thus the intensity of the radiated through the large area 25.1 useful light is increased. In contrast, at locations of higher intensity along the coordinate y, a lower density d and thus a lower Störvermögen provided, while still a sufficient amount of light passes as useful light through the large area 25.1 to the outside. It is therefore additionally achieved in the direction of the coordinate y equalization of the emitted light amount.

Of course, the coating 27 can not only be used to equalize the amount of light emitted by the large area 25.1, but it can be achieved with the variation of the density d, if this is given in a corresponding manner, above all, that by preferred surface sections of Large area 25.1 light is emitted with higher light intensity than by non-preferred surface sections. In this way, depending on the specification, light structures and light patterns can be generated which stand out from their surroundings on the large area 25.1 due to a greater or lesser brightness. Thus, in a simple example, a particularly bright spot in the middle of the radiating large area 25.1 can be achieved.

Alternatively, the entire large area can be painted 25.2 substantially homogeneous or mirrored, so that a lot of light through the large area 25.1 - but then not with a homogeneous distribution - is emitted.

An exemplary embodiment of the arrangement according to the invention for optionally three-dimensional or two-dimensional representation of a scene / object will be explained in more detail below with reference to FIG. 36, an illumination source being integrated in the embodiment according to FIG. The coating 27 is not mandatory in this case. However, if it is attached, then preferably using the above Silver particles with different properties with respect to the total reflection disturbance. In an alternative embodiment, it is conceivable to design the coating 27 in the form of a coating layer forming the filter array at the same time. However, for use in the arrangement for spatial representation, in both embodiments, patterns are to be omitted which correspond to the structure of the wavelength filter array used in such a way that a recess is preferably present in each case on the filter elements which are not opaque.

36, in the viewing direction B of an observer, the image reproduction device 18 in the form of a translucent LC display, the light guide 25, a wavelength filter array 20 and the plan illumination source 21 are arranged first, the latter for example as a Planon light tile (manufacturer "OSRAM"). ) may be formed.

To homogenize the intensity of the radiation emanating from the planlight source 21, a diffusing screen 29 is arranged between it and the wavelength filter array 20.

FIG. 36 again shows the light source 24 arranged near the narrow surface 25.3 of the light guide 25, already mentioned in the preceding exemplary embodiment, with the reflector 26 for coupling the radiation into the light guide 25. Both the light source 24 and the planlight source 21 are coupled to separately controllable on / off switches, which makes it possible to operate either only the light source 24 or only the planlight source 21 or both. Thus, as already described, the first and the second operating modes can be realized and the scene / object can be displayed over the whole area in two or three dimensions. The third operating mode is, as also already shown, possible with the separate activation of a selection of individual shutter elements of the shutter 23 (cf. Description for Fig.26).

In the first mode, in which the plan illumination source 21, but the light source 24 is turned off, reaches the illumination light through the wavelength filter array 20, the light guide 25 and the image display device 18 through the eyes of the observer, with both eyes, given by the position p, q of the filter elements relative to the positions i, j of the associated picture elements, different image information is offered and for the viewer a spatial impression of the scene displayed on the image display device or of the object arises. The shutter is activated ("open").

In the second mode, only the light source 24 is turned on, with the result that only light passes to the viewer, although coming from the large area 25.1 has passed the pixels of the image display device 18 and carries the image information with it, but not the wavelength filter array 20 happened. This eliminates the selection and direction preset for selected image information and their assignment to the right or left eye of the viewer, so that the scene / object is perceived not three-dimensional, but two-dimensional.

In the third mode, the light source 24 and the planlight source 21 are turned on. A predetermined number of shutter elements is, as already stated, so driven, that the illumination light reaches the viewer in selected areas both through the filter elements and through the associated picture elements and consequently with a predetermined propagation direction, while the illumination light in areas of the non-driven shutter elements only by the image display device, however, does not reach the viewer through assigned filter elements and therefore not with a predetermined propagation direction. As a result, the scene / object is two-dimensionally perceivable in areas of the non-controlled shutter elements, but can be perceived three-dimensionally in areas of the controlled shutter elements.

The coating 27, which is preferably formed in the example chosen here from dull and shiny silver particles, ensures in this case that as much useful light is emitted through the large area 25.1. The density structure of the coating 27 is formed, for example, as shown in Figure 29, whereby it is achieved that the intensity of the emitted over the large area 25.1 Nutzlichtes over the entire large area 25.1 is largely uniform and thus a uniformly distributed image brightness is guaranteed. As mentioned above, however, the coating 27 is not mandatory in this embodiment.

To even out the coupling of the light from the light source 24 in the light guide 25 25.3 (not shown) cylindrical lenses or also a lens may be provided in front of the narrow surface.

Another exemplary embodiment of the 2D-3D switching is to be presented below with reference to FIG. 37. In the arrangement according to FIG. 37, it is provided that the side 20.1 of a wavelength filter array 20 facing away from the planlight illumination source 21 is coated with scattering surface elements 30. The diffusing surface elements 30 are incorporated, for example, in a 0.5 mm thick disc by etching and this (not separately shown) disc is connected to the wavelength filter array 20.

The etches are provided only in surface regions which correspond to the opaque filter elements designated S in FIG. The remaining filter elements designated R ', G', B 'remain free of this etching or of scattering surface elements 30 and are thus freely transparent.

Adjacent to the thus structured outer surface of the wavelength filter array 20, additional light sources 31 are positioned, in such a way that the radiation emanating therefrom impinges on the scattering surface elements 30. The additional light sources 31 can also be assigned reflectors 32, which ensure an increase in the intensity of the radiation directed onto the scattering surface elements 30.

Preferably 31 are used as light sources rod-shaped lamps. When positioning the light sources 31, it should be noted that the side 20.2 of the wavelength filter arrays 20 facing the planlight source 21 is not illuminated thereby.

When the light sources 31 are switched on, the light emanating from there impinges on the scattering surface elements 30 and, due to the relatively small distance of only 3 mm between the wavelength filter array 20 and the image display device 18, illuminates the image raster of the image display device 18 in a relatively diffuse and homogeneous manner.

Again, the plan illumination source 21 and the light sources 31 are each separately switched on and off, so that, as already mentioned, the first and second modes can be set.

In the first mode, only the light sources 31 are turned on while the plan lighting source 21 is turned off. In this operating mode, the image or image displayed on the image display device 18 is for a viewer. the scene shown two-dimensionally perceptible, since the light coming from the image display device 18 to the viewer with respect to its direction is not affected by the assignment of filter elements and pixels, but uniformly radiates the image display device 18 and the light of all pixels equal rights reaches the eyes of the beholder.

In the second mode, the light sources 31 are turned off. The image display device 18 is illuminated exclusively by means of the planlight illumination source 21 through the wavelength filter array 20. In this mode, a direction selection takes place due to the positional assignment of filter elements and pixels, which as described ensures that each eye of the viewer only selected image information is visible and thus creates the three-dimensional impression for the viewer.

In order to realize the third mode of operation, a shutter may again be provided between the plane illumination source 21 and the wavelength filter array 20, which shutter consists of a multiplicity of individually controllable shutter elements which block or release predetermined regions of the light path as required. Controlling the switching on and off of the lamps and the shutter elements can in all cases be done via processors with the aid of software. Preferably, in this case the planlight source 21 is brighter than the light sources 31, ie the resultant luminance per unit area of ​​the planlight source 21 is higher than that of the light sources 31. This can be achieved by means of dimmers arranged in the supply circuit.

As shown in Fig.38, it may also be provided in a separate embodiment that only the planlight source 21 is present and the light emerging from the narrow surfaces of the planlight source 21 also on the side facing the wavelength filter array 20 reflectors 33 facing away from the planlight source 21 Area 20.1 of the wavelength filter array 20 can get.

The reflectors 33 are fixed so that the light emerging from the narrow surfaces of the planlight source 21 and directed to the reflectors 33 radiation is always deflected by these and directed to the surface 20.1 of the wavelength filter array 20. In each case controllable shutter 34 is provided between the light-emitting narrow surfaces and the reflectors 33, which block or release this light path depending on the control. When the light path to the reflectors is released, the scene / object is two-dimensionally perceptible three-dimensionally when the light path is blocked.

In a further embodiment, which is not shown in the drawing, missing the shutter 34, but the reflectors 33 are pivotally mounted. In this case, the radiation emanating from the plan illumination source 21 in a first pivot position is not directed to the surface 20.1 of the wavelength filter array 20, in a second pivot position on the surface 20.1 of the wavelength filter array 20.

In this way, it is ensured in the first pivot position that the light emanating from the planlight source 21 passes through the wavelength filter array 20 as well as through the image display device 18 to the viewer, while in the second pivot position also light passes to the viewer, as described is not affected by the assignment of filter elements to pixels. Thus, in the first case, the three-dimensional, in the second case the two-dimensional perception is possible.

As in the embodiment according to FIG. 37, here too, on the surface 20. 1 of the wavelength filter array 20, preferably on the local opaque surface regions designated by S (cf. 2), scattering surface elements 30 may be provided, of which the laterally incident light uniformly reaches the rear side of the image display device 18 and then passes therethrough to the viewer. Instead of the scattering surface elements, reflective surface elements may alternatively be provided.

In the context of the invention, it is also the case that reflective surface elements are also applied to the side 20.2 of the wavelength filter array 20 which faces the planlight source 21, whereby light incident beyond a certain critical angle is reflected by the surface 20.2 , on the other hand, is transmitted below this critical angle, such as light that is incident perpendicularly.

In this way, the obliquely incident on the wavelength filter array 20 light can be used on the side mounted reflectors partially to illuminate the scattering surface elements 30, while the wavelength filter array 20 is still still irradiated.

In further, deviating embodiments of the invention, it is also conceivable to use a black and white display with the exclusive use of neutral filters in the filter array instead of a color display. In this connection, based on the construction of the arrangement according to the invention shown in FIG. 10, a further exemplary embodiment for 2D-3D switching is to be explained below, in which neutral filters are used.

As shown in Fig.10, the filter array 8 is located with the filter elements β_why seen from the position of the viewer 1 in the distance z in front of the imaging color LC display 2. The color LC display 2 is connected to the underlying surface illumination device 4 to form a structural unit. The propagation directions of the coming of the subpixels R, G, B of the color LC display 2 and by the corresponding filter elements β_why of the filter array 2 of radiating light intersect in the viewing space 7 in a multiplicity of viewing positions, from which the represented object or the scene is spatially perceptible.

FIG. 39 shows an example of the embodiment of the filter array 8 as a filter array with individual neutral filters L0, L2 and L4. For the sake of clarity, this illustration is greatly enlarged and not drawn to scale. The partial surfaces correspond to neutral filters which are 0% (L0), 50% L (L2) and 100% (L4) of the incident light (based on the light intensity) transmitted wavelength independently. The faces are simplified square shown; on the exact representation of the shape of the neutral filter L0, L2, L4 was omitted here. They are preferably rectangular and have, for example, a width of 99 microns and a height of 297 microns.

The filter array structure shown in Fig. 39 can be generated by the equation (F2) in which the values ​​d_why= -1 = const. and n_m = 8 starts. The transmission properties λ_b are chosen here as follows:<ul id="ul0007" list-style="dash" compact="compact"><li>λ_8th corresponds to a wavelength independent to 100% transmitting filter (L4 in the drawing), ie the transmittance is 100%;</li><li>λ_one and λ₇ correspond to wavelength-independent to 50% transmissive filters (L2 in the drawing), ie the transmittance is 50%;</li><li>λ₂... λ₆ correspond to wavelength-independent non-transmissive (opaque) filters (L0 in the drawing), ie the transmittance is 0%.</li></ul>In this case, the transmission properties are decisive, in particular with regard to the visible spectrum, ie an L4 filter can certainly be intransparent for electromagnetic radiation, for example in the UV range.

3 shows an example of the combination of partial information of different views A._k (k = 1 ... 8) in a plan view of the grid of the color LC display 2, according to the already described function (F1) with the parameters c_ij= -1 = const. and n = 8 has been generated and is well suited for spatial presentation in conjunction with a filter array structure of Fig. 39.

FIG. 40 shows a filter array 8 which has neutral filters (L2) which, with reference to the light intensity, transmit about 50% of the light passing through them in a wavelength-independent manner. The filters L0 are opaque, while the exemplary incorporated filter elements R ', G', B 'for light of the color ranges red, green or blue are translucent.

Again, it is possible to use completely different wavelength ranges of transparency than R ', G', B 'for the filter elements, which moreover need not be limited to the range of visible light.

FIG. 41 schematically shows a further possibility of the image combination. Here n = 40 views are used. An exemplary, for a three-dimensional representation favorable filter structure for this image combination is shown in Fig.42. In this case, wavelength-independent neutral filters are used to attenuate the light intensity, in each case 0% (L0), 25% (L1), 50% (L2), 75% (L3) or 100% (L4) of the (visible) light incident on them transmit. The filters in this embodiment preferably have about one quarter of the width of the picture elements α_ij, that is, the subpixel, while being approximately the same in height as the picture elements α_ij,

Such an arrangement has the particular advantage that virtually from each viewing position, an eye of a viewer sees almost all displayed image information of a particular group of views (increasingly more image information of the next adjacent views, but overall views are always predominantly views of the particular group).

A possibly advantageous combination image using n = 40 views is shown by way of example in FIG. A corresponding filter array is shown in FIG. The width of the filter elements β_why is in this case about only one fifth of the width of the picture elements α_ij,

From Fig. 45 it can be seen that a viewer's eye predominantly a first selection of views A_k (k = 1..n), whereby the visibility of one of these views predominates and others, in this case adjacent views, are also partly seen. However, the representation in Fig. 45 is idealized; in fact, under the filter array, of the pixels α_ij (or the subpixels on which the corresponding image information is displayed) always slightly more or slightly less visible than the proportions shown here, depending on the viewing distance.

Further embodiments in this sense are conceivable, for example, with n = 60, n = 72, n = 90 or n = 1 10 views.

Another embodiment of a filter array is shown in FIG. There has a wavelength filter element β_why about one fifth of the width of a picture element α_ijin which not only transparent opaque filters are provided in the filter array, but also colored wavelength filter elements β_why such as R ', G', B '. This will produce a brighter picture. An image combination rule which is well suited for this purpose is shown as a detail in FIG.

It is known in the prior art to convey to a viewer a stereoscopic image whose one field has a good, the other a poor image resolution, whereby the viewer usually perceives the spatial image subjectively nevertheless with the high resolution.

An exemplary image combination structure utilizing the above-described effect on the basis of n = 8 views is shown in fragmentary form in FIG. Corresponding to this, a filter array, which is shown in fragmentary form in FIG. 48, can be used. The favorable effect of such a constellation is that the image information of each odd-numbered view has a higher resolution than the even-numbered views.

In most cases, a viewer with at least one of his eyes sees on average predominantly picture elements of an odd-numbered view, since the probability is comparatively low that he sees with both eyes predominantly portions of even-numbered views. Thus, the subjective perceived image resolution can be increased.

FIGS. 49a, 49b and 49c show examples of polygonal filter elements. These or other polygonal shapes can contribute to the reduction of moiré effects and, in contrast to the change in the outer shape of picture elements in LC or plasma picture screens, can be manufactured in a simple manner during the production of the filter arrays.

In order to achieve that a viewer selected from multiple viewers, despite his changing eye position almost exclusively the middle of the views A_k (k = 1... n), a device for displacing the filter array perpendicular to the viewing direction of this observer is provided in a particular embodiment.

As schematically indicated in FIG. 50, a related arrangement comprises a color LCD display 40 for image display with drive circuit 41 and a filter array 42 coupled to a mechanical displacement device 43 for displacement perpendicular to the viewing direction of the selected viewer 44, which interacts with other viewers in viewing room 45 stops.

The displacement device 43 is formed in an exemplary embodiment of a stepper motor (with a corresponding drive) and guide rails for the filter array 42. In this case, the filter array 42 is laminated on a support, for example a glass sheet. This glass with the filter array 42 is guided at its upper edge or lower edge in a rail, with additional means for reducing the friction (eg rollers) may be provided.

A tracking device for real-time detection of the eye position of a selected observer 44, not shown in the drawing, supplies information to the control unit of the displacement device 43 via a computing device. This causes the displacement of the filter array 42 continuously with the aim that the selected observer 44 predominantly always the same, pairwise different views A_x and A_Y from the views A_k (k = 1..n) perceives.

The inertia or hysteresis of this control loop, which consists of tracking and displacement device 43, is now compensated by the fact that too slow displacement or overshooting shift of the filter array 42 compared with the respective target position exactly desired next to the aforementioned central views A_x and A_Y still give a correct 3D impression for the selected viewer 44. This can be particularly advantageous when large-scale screens (eg, a plasma display of the above type) as 3D screens are to be assembled, because in these cases the mass and thus the inertia of the filter array 42 (and optionally the carrier material) and the inertia or hysteresis of said control circuits can be particularly large.

While the selected viewer 44 is essentially always the views A_x and A_Y sees, the other observers can also perceive an orthoscopic autostereoscopic 3D image. If the selected viewer 44 moves, only the perspective of the other viewers changes. In the event that this causes a viewer in the transition zone of the views, the so-called jump point at which the period of the horizontally adjacent views again begins (ie in the transition area of ​​the last view A_n to the first view A_one passes) such a viewer can get back into an orthoscopic viewing area by a slight lateral head movement.

This embodiment offers many advantages over the prior art. In particular, a selected viewer 44 without aids such as glasses can see a correct spatial image from essentially the same perspective. Pseudoscopic phenomena can be avoided for this selected viewer even when using very large image display devices and the associated quite large-sized optical assemblies that are necessary for spatial perception, while a variety of other viewers can see the same scene without tools also spatially.

In a further embodiment, not only the filter array is moved, but also the image content, ie the views and the resulting combination image, is continuously and preferably recalculated in real time according to the position of the selected viewer. As a result, the selected viewer is effectively enabled to walk around the displayed spatial scene.

Such a device can serve, in particular, to provide a person entrusted with an important task, such as a surgeon, with the same perspective permanently and furthermore with an always correct spatial view, while an auditorium should also see a spatial image, which, however, is easy in terms of perspective can change. For example, this could be a group of medical students attending an operation.

In a further embodiment of the arrangement according to the invention for reproducing the partial information of the views A_k (k = 1..n) on picture elements α_ij in the grid (i, j) a plasma display, for example of the type Pioneer PDP-502MXE provided.

A related structure is shown in Fig.51 schematically and not to scale. The here indicated plasma display 35 with the frame 36 is driven by a graphic not shown electronics such that the pixels α_ij of the grid (i, j) relate their image information from the perspective views according to the combination rule shown in detail in Fig.41. The grid (i, j) here refers to the arrangement of the picture elements α_ij as RGB subpixels of the plasma display, ie the column i = 1 contains only red pixels (subpixels), while the column i = 2 contains only green pixels (subpixels), whereupon in the next column i = 3 the blue subpixels follow etc This is indicated by the letters R, G, B in Fig.41.

At a distance z in front of the plasma display 35 is the carrier material 37 with a filter structure in the form of a filter array 38, of which in Fig.52 a section is not drawn to scale. Note the difference between the grid (i, j) for the picture elements α_ij and the grid (p, q) for the area elements of the filter array structure, in particular as regards the width of the area elements of the two screens (i, j) and (p, q) in the physical version (see below).

In Figure 51, the substrate 37 and filter array 38 have been drawn separately for illustrative purposes, however, substrate 37 and filter array 38 are typically formed as a unitary assembly.

The distance z between the filter array 38 and the grid (i, j) of pixels α_ij, ie the plasma display 35, measured in the viewing direction, is determined according to the following equation for the exemplary embodiment: <maths id="math0012" num="(f7)"><math display="block"><mrow><mrow><mo>(</mo><mrow><mi mathvariant="normal">F</mi><mn>7</mn></mrow><mo>)</mo></mrow><mi> </mi><mfrac><mi>with</mi><mrow><msub><mi>s</mi><mi>p</mi></msub></mrow></mfrac><mo>=</mo><mfrac><mrow><msub><mi>d</mi><mi>a</mi></msub></mrow><mrow><msub><mi>p</mi><mi>d</mi></msub></mrow></mfrac></mrow></math><img file="EP1689162A2_D0012.tif" /></maths> Hereby means:<ul id="ul0008" list-style="dash" compact="compact"><li>s_p the average horizontal distance between two picture elements α_ij.</li><li>p_d the mean pupil distance in a viewer and</li><li>d_a a selectable viewing distance, which substantially corresponds to the average of all possible distances in the entire viewing space between the filter array 38 and a viewer or a viewing position.</li></ul>

In the specific case of a picture display device based on a Pioneer PDP-502MXE, taking into account the RGB subpixel structure s_p = 286 μm, If p_d= 65 mm and d_a= 2,000 mm, then z = 8.8 mm.

The possible structure of a filter array with n = 40 views is shown in fragmentary form in FIG. Such a structure is well suited for example in connection with a combination image according to Fig.41. In the production of the filter array 38, the grid (p, q) of the filter structure should preferably be in its physical horizontal or vertical dimensions substantially with the physical horizontal or vertical dimensions of the grid (i, j) match, ie The horizontal extent of a surface element of the grid (p, q) is here for example approximately one quarter of the horizontal extent of a surface element of the grid (i, j), while the vertical extent of the corresponding surface elements substantially coincides. It follows that the surface elements of the grid shown in Fig.41 (i, j), ie the picture elements α_{ij '} in FIG. 41 (see below), in practice, assume the width of approximately four surface elements of the grid (p, q) (the filter structure).

Accordingly, for the plasma display Pioneer PDP-502MXE, a surface element in the raster (p, q) of the filter structure is for example 71.5 μm wide and 808 μm high. Preferably, all opaque filter elements are made electrically conductive and electrically conductively connected to each other.

Two examples of methods for producing the above-described at least partially conductive filter array 38 will now be explained in more detail.

In a first example for producing a filter array 38 in which at least every tenth filter element 39 is electrically conductive, the method comprises the two method steps:<ul id="ul0009" list-style="dash" compact="compact"><li>Preparing a screen printing mask using an electrically conductive paint, such as SPI Conductive Carbon Paint (Manufacturer: Structure Probe, Inc., USA), wherein at least every tenth non-transparent predetermined filter element is made by means of this conductive color, and</li><li>Screen printing the filter structure on a transparent carrier material, eg PMMA or glass.</li></ul>

If not only opaque but also other wavelength-selective filter elements are to be mounted on the filter structure, the filter array 38 thus produced on the carrier material 37 can also pass through the screen printing process a number of times, whereby the filters of a certain wavelength-transparency range can be applied each time.

A second example of manufacturing the filter array 38 in which at least one tenth filter element 39 is electrically conductive comprises the following steps:<ul id="ul0010" list-style="dash" compact="compact"><li>Preparing a printing mask using metallic particles, eg silver particles, wherein at least every tenth non-transparent predetermined filter element 39 is formed by means of said particles,</li><li>Coating a transparent carrier material, eg PMMA or glass, with a transparent adhesive (eg Acrifix 192 adhesive, manufacturer: Röhm GmbH Darmstadt),</li><li>Printing the filter structure on the substrate and</li><li>if necessary, exposure, eg UV exposure, of the coating to cure the adhesive. The metallic particles are in this case essentially only for opaque filter elements in question.</li></ul>

This embodiment of the invention offers the advantage that ordinary glass or PMMA disks can be used instead of electrically conductive, transparent front screens for plasma displays. This also simplifies the conversion from ordinary plasma screens to 3D screens, since then no additional filter array has to be applied to a special front screen.