Projection type image display device and image display system

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a projection type image display device that decomposes illumination light from an illumination optical system into a plurality of color lights, synthesizes each color light modulated by an image display element, and projects and displays an image.

【0002】

[Conventional technology]

A projection type image that magnifies and projects the image light from the image display element using an illumination optical system that illuminates the image display element and an image display element such as a liquid crystal display that modulates the polarization state of the illumination light to generate image light. Display devices have been used conventionally.

【0003】

Then, an image using a so-called reflective image display element, in which the side where the illumination light from the illumination optical system is incident on the image display element and the side where the image light modulated by the image display element is emitted is the same. As a display device, Japanese Patent Application Laid-Open No. 10-319344 has been proposed.

【0004】

FIG. 14 shows the configuration of a conventional projection type image display device. In this figure, 101 is a light source, 102 is a reflector, 103 is a filter, and 104,106 are fly-eye lenses. Further, 105 is a mirror, 107 is a polarization beam splitter, 108 is a color separation synthesis prism, 109r, 109g, 109b are image display elements, and 110 is a projection lens.

【0005】

Here, the optical path IL of the illumination optical system and the optical path PL of the projection optical system are combined by a polarizing beam splitter 107 so as to pass through a single color separation synthesis prism 108.

【0006】

[Problems to be Solved by the Invention]

However, the characteristics of the dichroic film in the color separation synthesis prism vary depending on the angle of incidence. When the light (illumination light) incident on the image display element is incident as a light flux having a predetermined spread, the incident angle varies according to the spread angle of the light flux in the dichroic film, and as a result, color components other than the predetermined color component are generated. Is mixed with the illumination light, and there is a problem that the color purity of the illumination light is lowered.

【0007】

[Means for solving problems]

In order to solve the above problems, in the first invention of the present application, an illumination optical system and an image display element provided by decomposing the illumination light from the illumination optical system into a plurality of color lights and providing each color light for each color light. Projection having a color-resolved synthetic optical system that synthesizes image lights of a plurality of colors emitted from these image display elements and a projection optical system that projects and displays the image light synthesized by the color-resolved synthetic optical system. In the type image display device, a color adjusting means for narrowing the wavelength band of the color light incident on the image display element is provided between the color separation synthesis optical system and at least one image display element.

【0008】

Further, in the second invention of the present application, the illumination optical system and the illumination light from the illumination optical system are decomposed into a plurality of color lights, and each color light is incident on an image display element provided for each color light, and these images are formed. Illumination in a projection type image display device having a color separation synthesis optical system that synthesizes image light of a plurality of colors emitted from a display element and a projection optical system that projects and displays the image light synthesized by this color separation synthesis optical system. Between the optical system and the color-resolved synthetic optical system, the illumination light from the illumination optical system is reflected with a reflectance close to 100% to guide the color-resolved synthetic optical system and the image light from the color-resolved synthetic optical system. A light guide element that transmits light to the projection optical system is provided so that the optical path of the illumination light and the optical path of the image light in the light guide element and the color separation synthesis optical system are different from each other, and at least one with the color separation synthesis optical system. A color adjusting means for narrowing the wavelength band of the color light incident on the image display element is provided between the image display element.

【0009】

Further, in the third invention of the present application, the illumination optical system and the illumination light from the illumination optical system are decomposed into a plurality of color lights, and each color light is incident on an image display element provided for each color light, and these images are formed. Illumination in a projection type image display device having a color separation synthesis optical system that synthesizes image light of a plurality of colors emitted from a display element and a projection optical system that projects and displays the image light synthesized by this color separation synthesis optical system. Between the optical system and the color-resolved synthetic optical system, the illumination light from the illumination optical system is reflected with a reflectance close to 100% to guide the color-resolved synthetic optical system, and the image light from the color-resolved synthetic optical system is transmitted. A light guide element that allows light to pass through the projection optical system is provided, and the light guide element for light rays along the center line of the illumination light beam in the illumination optical system, the color separation synthesis optical system, and the trace line in the projection optical system are used as the reference axis of the entire system. When this is done, the reference axis in the color separation synthesis optical system (or illumination optical system) and the reference axis in the projection optical system are tilted with respect to the normal line of the display surface of the image display element, and the color separation synthesis optical system is used. A color adjusting means for narrowing the wavelength band of the color light incident on the image display element is provided between the system and at least one image display element.

【0010】

In these second and third inventions, as the light guide element, for example, the first surface on which the illumination light is incident and the illumination light are emitted toward the color separation synthesis system and from the color separation synthesis optical system. The second surface on which the image light is incident and the illumination light incident from the first surface are reflected toward the second surface with a reflectance close to 100%, and the image light incident from the second surface is reflected. It can be composed of a prismatic optical element having a third surface to be ejected toward the projection optical system.

【0011】

Further, in the fourth invention of the present application, the illumination optical system and the illumination light from the illumination optical system are decomposed into a plurality of color lights, and each color light is incident on an image display element provided for each color light, and these images are formed. Illumination in a projection type image display device having a color separation synthesis optical system that synthesizes image light of a plurality of colors emitted from a display element and a projection optical system that projects and displays the image light synthesized by this color separation synthesis optical system. Between the optical system and the color-resolved synthetic optical system, the illumination light from the illumination optical system is transmitted to the color-resolved synthetic optical system, and the image light from the color-resolved synthetic optical system is reflected with a reflectance close to 100%. A light guide element that leads to the projection optical system is provided so that the optical path of the illumination light and the optical path of the image light in the light guide element and the color separation synthesis optical system are different from each other, and at least one with the color separation synthesis optical system. A color adjusting means for narrowing the wavelength band of the color light incident on the image display element is provided between the image display element and the image display element.

【0012】

Further, in the fifth invention of the present application, the illumination optical system and the illumination light from the illumination optical system are decomposed into a plurality of color lights, and each color light is incident on an image display element provided for each color light, and these images are formed. Illumination in a projection type image display device having a color separation synthesis optical system that synthesizes image light of a plurality of colors emitted from a display element and a projection optical system that projects and displays the image light synthesized by this color separation synthesis optical system. Between the optical system and the color-resolved synthetic optical system, the illumination light from the illumination optical system is transmitted to the color-resolved synthetic optical system, and the image light from the color-resolved synthetic optical system is reflected with a reflectance close to 100%. A light guide element is provided to guide the light to the projection optical system, and the light guide element for light rays along the center line of the illumination light beam in the illumination optical system, the color separation synthesis optical system, and the trace line in the projection optical system are used as the reference axis of the entire system. When this is done, the reference axis in the color separation synthesis optical system (or illumination optical system) and the reference axis in the projection optical system are tilted with respect to the normal line of the display surface of the image display element, and the color separation synthesis optical system is used. A color adjusting means for narrowing the wavelength band of the color light incident on the image display element is provided between the system and at least one image display element.

【0013】

In the fourth and fifth inventions, the light guide element includes, for example, a first surface that incidents illumination light and reflects image light with a reflectance close to 100%, and the first surface. A second surface in which the illumination light incident from the above is emitted toward the color-resolved synthetic optical system and the image light from the color-resolved synthetic optical system is incident, and the second surface in which the image light is incident from the second surface is incident on the first surface. It can be composed of a prism-shaped optical element having a third surface for emitting the reflected image light toward the projection optical system.

【0014】

In the above first to fifth inventions, the wavelength band of the colored light that illuminates each image display element is determined by the characteristics of a film such as a dichroic film possessed by the color-resolved synthetic optical system. By providing a color adjusting means such as a dichroic filter that narrows the wavelength band of colored light between the image display element and the image display element, the film characteristic of the color-resolved synthetic optical system changes from the transmitted wavelength band to the reflected wavelength band from the colored light. Since the wavelength band component light can be removed, it is possible to increase the purity of the color light and expand the range of color reproduction.

【0015】

Further, in general, the wavelength band component light in the region where the film characteristics of the color separation synthetic optical system changes from the transmission wavelength band to the reflection wavelength band depends on the difference in the phase characteristics between P-polarized light and S-polarized light in the film of the color separation synthesis optical system. It causes the polarization state to be disturbed and the image contrast to be lowered, but this can be improved by providing the color adjusting means as in the present invention.

【0016】

Then, according to the second to fifth inventions of the present application, it is possible to separate the optical path of the illumination light and the optical path of the image light without providing a polarizing beam splitter as in the conventional case. Moreover, since the light guide element reflects the illumination light from the illumination optical system or the image light from the color separation synthetic optical system with a reflectance close to 100% and guides it to the color separation synthetic optical system or the projection optical system, it is conventional. Compared with the projection type image display device, the light utilization efficiency can be improved, and a bright and high-definition display image can be obtained.

【0017】

Further, as in the third and sixth inventions, the reference axis in the color separation synthesis optical system (or the illumination optical system) and the reference axis in the projection optical system are set with respect to the normal of the display surface of the image display element, respectively. If it is set to be tilted, the projection optical system can be miniaturized.

【0018】

Here, if the reference axis of the illumination optical system is arranged at an inclination angle θ tilted with respect to the normal line of the image display element, the reference axis of the projection optical system is also tilted θ tilted to the opposite side with respect to the normal line of the image display element. Is placed. At this time, if the tilt angle θ is increased, the angle 2θ formed by the reference axis of the illumination optical path and the reference axis of the projection optical path becomes larger, and the angle ω at which the projection optical path (or illumination optical path) is incident on the light guide element becomes smaller, and the light guide It is possible to make the transmittance of all the light rays passing through the element by the incident angle more uniform. Further, in the illumination optical system, the smaller the F number of the illumination optical system, the better the efficiency.

【0019】

On the other hand, in an eccentric optical system, the smaller the tilt angle θ of the object surface (image display element), the smaller the amount of eccentric aberration, and the larger the F number of the projection optical system, the easier it is to correct the aberration.

【0020】

By setting the projection optical system as an eccentric optical system having at least one rotationally asymmetric surface or a plurality of optical elements having different rotational symmetry axes, eccentric aberration such as keystone distortion generated by tilting the projection optical system. Can be corrected.

【0021】

Further, when the light guide element is formed in a wedge shape, an auxiliary optical element that refractes and transmits the image light emitted from the light guide element between the light guide element and the projection optical system is air-spaced with respect to the light guide element. By arranging them with a space between them, or by arranging an auxiliary optical element that refractes and transmits the illumination light from the illumination optical system between the light guide element and the illumination system with an air gap with respect to the light guide element. , It is possible to alleviate the aberration generated in the wedge shape.

【0022】

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows the configuration of a projection type image display device according to the first embodiment of the present invention. In the figure, 1 is an illumination light source composed of a high-pressure mercury lamp or the like, and 2 is a reflector for radiating the light from the light source 1 in a predetermined direction.

【0023】

Reference numeral 3 denotes an integrator for forming a uniform illumination region, which is composed of fly-eye lenses 3a and 3b.

【0024】

Reference numeral 4 denotes a polarization conversion element that aligns unpolarized light in a predetermined polarization direction, and is composed of a polarization separation film 4a, a reflection film 4b, and a 1/2 phase plate 4c.

【0025】

Reference numeral 5 denotes a condensing optical system that collects illumination light, which is composed of lenses 5a and 5b and a mirror 5c. The light source 1 to the lens 5b constitute an illumination optical system within the claims.

【0026】

Reference numeral 6 denotes an optical path prism (light guide element) for setting the optical path so that the optical paths of the illumination optical system and the projection optical system pass through one color-resolved synthetic optical system.

【0027】

Reference numeral 7 denotes a dichroic prism (color separation synthesis optical system) for decomposing the optical path into three colors of R, G, and B and synthesizing them again. In this embodiment, the three prisms are combined to form a predetermined combination surface. It is constructed by depositing a dichroic film or the like.

【0028】

8r, 8g, 8b are reflective image display elements for each color light composed of a liquid crystal display, etc., and correspond to image information from an image information supply device such as a personal computer, a television, a video, or a DVD player (not shown). Driven by a signal, it reflects and modulates the incident illumination light of each color and emits it.

【0029】

9 is an auxiliary prism (auxiliary optical element), and 10 is an eccentric projection lens (projection optical system). P is a polarizer for the image display elements 8r, 8g, 8b, and A is an analyzer for the image display elements 8r, 8g, 8b.

【0030】

Tr and Tb are dichroic filters (color adjusting means) arranged between the dichroic prism 7 and the reflective image display elements 8r and 8b for red and blue, respectively.

【0031】

Next, the optical operation of the projection type image display device configured as described above will be described. The illumination light flux emitted radially from the light source 1 is reflected by the reflector 2 and focused toward the fly-eye lens 3a. This illumination luminous flux is separated into a plurality of luminous fluxes by the fly-eye lens 3a, and then superimposed on the image display elements 8r, 8g, 8b by the action of the fly-eye lens 3b and the lenses 5a, 5b to display a uniform illumination area as an image. Formed on the element.

【0032】

Further, a large number of light fluxes emitted from the fly-eye lens 3b are separated into P-polarized light and S-polarized light by a polarization separation membrane 4a corresponding to each light flux. The P-polarized light is converted into a polarization component in the same direction as the S-polarized light by the 1/2 phase plate 4c, and the S-polarized light is reflected by the reflective film 4b and emitted in the same direction as predetermined polarized light.

【0033】

As shown in FIG. 2, the illumination luminous flux is incident on the first surface 6a to the second surface 6b of the optical path prism 6 at an angle satisfying the total reflection condition and is totally reflected. As a result, reflection with a reflectance close to 100% is obtained, the optical path is bent, and then the light is emitted from the third surface 6c.

【0034】

In the present embodiment, the case where the illumination light is totally reflected by the second surface 6b of the optical path prism 6 will be described, but the reflection by the second surface 6b is a part of the outside of the second surface 6b. It may be reflected by a mirror coat formed by vapor deposition or the like.

【0035】

Further, in the present embodiment, a 3P prism composed of three prisms (first to third prisms P1 to P3) is used as the dichroic prism 7.

【0036】

In FIG. 2, the light of B (blue) incident from the first surface 7a of the first prism P1 is reflected by the first dichroic surface 7db, and the light of R (red) and G (green) is transmitted. ..

【0037】

The light of B is reflected on the first surface 7a with a reflectance close to 100% (for example, total reflection), then emitted from the second surface 7b, transmitted through the dichroic filter Tb, and the image display element 8b for B is transmitted. To.

【0038】

The light of R and G transmitted through the first dichroic surface 7db is incident from the third surface 7c of the second prism P2 arranged with a slight air gap from this surface 7db, and the light of R Light is reflected by the second dichroic surface 7dr, and G light is transmitted.

【0039】

The light of R is reflected on the third surface 7c with a reflectance close to 100% (for example, total reflection), then emitted from the fourth surface 7d, transmitted through the dichroic filter Tr, and sent to the image display element 8r for R. To reach.

【0040】

The light of G transmitted through the second dichroic surface 7dr is incident on the third prism P3 and then emitted from the fifth surface 7e to reach the image display element 8g for G.

【0041】

Each color illumination light incident on each image display element is reflected by being modulated in its polarization state by each image display element driven by a signal corresponding to the image information.

【0042】

The image light modulated and reflected by each image display element is reflected in a direction different from the incident direction of the illumination light, the R and B lights pass through the dichroic filters Tr and Tb, and the G light remains dichroic. It is incident on the prism 7, and is combined again into one and ejected through the reverse path of the above-mentioned color separation.

【0043】

The light emitted from the dichroic prism 7 is incident on the optical path prism 6 from the third surface 6c at an angle smaller than the angle satisfying the total reflection condition on the second surface 6b, and is transmitted through the second surface 6b. Eject.

【0044】

The light emitted from the optical path prism 6 is transmitted while refracting the auxiliary prism 9, and is projected as a full-color image on a screen (not shown) by the eccentric projection lens 10 of FIG.

【0045】

Here, in FIG. 1, assuming that the reference axis of the illumination optical system is the central axis of the illumination light beam, the reference axis of the optical system is a fly-eye lens 3a, in which light rays along the optical axis of the reflector 2 are provided thereafter. It can be considered as a straight line traced by an illumination optical system (5a, 5b, 5c) other than 3b, an optical path prism 6, a dichroic prism 7, an image display element 8r to 8b, an auxiliary prism 9, and an eccentric projection lens 10, respectively.

【0046】

Based on this, in FIG. 1, IL is set as the reference axis of the illumination optical system, and PL is set as the reference axis of the projection optical system.

【0047】

In this embodiment, as shown in FIG. 2, the reference axis IL after color separation of the illumination optical system (that is, the reference axis of the color separation synthetic optical system) IL and the reference axis PL of the projection optical system are the image display elements 8r, respectively. Both are set to be tilted by θ with respect to the normal of the display surface of ~ 8b. As a result, the angle formed by the reference axis IL of the illumination optical system and the reference axis PL of the projection optical system becomes 2θ.

【0048】

When the tilt angle θ is increased, the angle 2θ formed by the reference axis of the illumination optical path and the reference axis of the projected optical path is increased, the angle ω at which the image light (or illumination light) is incident on the optical path prism 6 is decreased, and the optical path prism 6 is increased. The transmission rate of all the transmitted light rays depending on the incident angle can be made more uniform. Further, in the illumination optical system, the smaller the F number of the illumination optical system, the better the efficiency.

【0049】

On the other hand, in the eccentric optical system, the smaller the tilt angle θ of the object surface (image display element), the smaller the amount of eccentric aberration, and the larger the F number of the eccentric projection lens 10, the easier it is to correct the aberration.

【0050】

FIG. 3 shows the color separation characteristics of the dichroic prism 7 in the present embodiment, and FIG. 4 shows the characteristics of the dichroic filters Tr and Tb.

【0051】

In FIG. 3, the cut wavelengths of the dichroic prism 7 are set to λ1 = 510 nm and λ2 = 570 nm, and the fine solid line represents the light of B, the thick solid line represents the light of G, and the broken line represents the light of R. ..

【0052】

Further, in FIG. 4, the dichroic filter Tb for B light is an edge filter having a cut wavelength of 480 nm, and the dichroic filter Tr for R light is an edge filter having a cut wavelength of 600 nm.

【0053】

As a result, the wavelength region light of 480 to 510 nm and 570 to 600 nm is removed from the white light emitted from the light source, and the white light balanced with the color light having high color purity is reproduced.

【0054】

Light in the wavelength band cut by the dichroic filters Tr and Tb is reflected without changing the polarization direction and absorbed by the polarizing plate A of the projection system.

【0055】

As described above, in the present embodiment, the wavelength band of the colored light that illuminates each image display element 8r to 8b is determined by the characteristics of the dichroic film possessed by the dichroic prism 7, but the dichroic prism 7 and the image display element By providing dichroic filters Tr and Tb that narrow the wavelength band of colored light between 8r and 8b, the wavelength band component light in the region where the dichroic film characteristics of the dichroic prism 7 change from the transmitted wavelength band to the reflected wavelength band from the colored light. Therefore, the purity of the color light can be increased and the range of color reproduction can be expanded.

【0056】

Further, in general, the wavelength band component light in the region where the film characteristics of the color-resolved synthetic optical system changes from the transmission wavelength band to the reflected wavelength band depends on the difference in the phase characteristics between P-polarized light and S-polarized light in the film of the color-resolved synthetic optical system. It causes the polarization state to be disturbed and the image contrast to be lowered, but this can be improved by providing the dichroic filters Tr and Tb as in the present embodiment.

【0057】

Further, in the present embodiment, the illumination light from the illumination optical system is reflected between the illumination optical system and the dichroic prism 7 with a reflectance close to 100% to be guided to the dichroic prism 7 and emitted from the dichroic prism 7. An optical path prism 6 that transmits the image light to the eccentric projection lens 10 side is provided so that the optical path of the illumination light and the optical path of the image light in the optical path prism 6 and the dichroic prism 7 are different from each other. It is possible to separate the optical path of the illumination light and the optical path of the image light without providing the polarized beam splitter. Moreover, the optical path prism 6 reflects the illumination light from the illumination optical system with a reflectance close to 100% and guides it to the dichroic prism 7, and directs the image light from the image display elements 8r to 8b toward the eccentric projection lens 10. It can be made transparent.

【0058】

Therefore, the light utilization efficiency can be improved as compared with the conventional projection type image display device, and a bright display image can be obtained.

【0059】

Further, in the present embodiment, the reference axis of the projection optical system is tilted by using the eccentric projection lens 10 as an eccentric optical system having at least one rotationally asymmetric surface or a plurality of optical elements having different rotational symmetry axes. It is possible to correct eccentric aberration such as keystone distortion generated in.

【0060】

Further, in the present embodiment, the optical path prism 6 is formed in a wedge shape, and an auxiliary prism 9 that refracts and transmits the image light emitted from the optical path prism 6 is provided between the optical path prism 6 and the eccentric projection lens 10. Since the optical path prisms 6 are arranged at intervals of air, the aberration generated in the wedge shape can be alleviated.

【0061】

(Second Embodiment) FIG. 5 shows the configuration of the projection type image display device according to the second embodiment of the present invention. The components common to the first embodiment are designated by the same reference numerals as those of the first embodiment and are replaced with explanations.

【0062】

The present embodiment is different from the first embodiment in that the dichroic filters Tr and Tb provided between the dichroic prism 7 and the image display elements 8r and 8b can be inserted and removed from the optical path.

【0063】

When the dichroic filters Tr and Tb are inserted in the optical path, the color components of the projected light are as shown in FIG. 4 of the first embodiment, but when the dichroic filter Tr and Tb are removed from the optical path, The color components of the projected light are as shown in Fig. 3.

【0064】

In this case, the color purity of the light of R and B decreases, but the amount of light increases because the component of the projected light increases. This makes it possible to switch between a state of high color purity and a state of bright brightness.

【0065】

(Third Embodiment) FIG. 6 shows the configuration of the projection type image display device according to the third embodiment of the present invention. The components common to the first embodiment are designated by the same reference numerals as those of the first embodiment and are replaced with explanations.

【0066】

This embodiment is different from the first embodiment in that a dichroic filter unit PDr, PDg, PDb with a polarizing plate is provided between the dichroic prism 7 and the image display elements 8r, 8g, 8b to perform color adjustment.

【0067】

In the present embodiment, the dichroic filter units PDr, PDg, and PDb are provided between the polarizing plate and the image display element in each color optical path, and are used in combination with the phase plate. In addition, the polarizing plates of the dichroic filter units PDr, PDg, and PDb also serve as a polarizer for illumination light and an analyzer for the projection system.

【0068】

FIG. 7 shows a detailed view of the optical path of G. The dichroic filter unit PDg with a polarizing plate is configured by laminating a polarizing plate Pg, a first 1/4 phase plate R1, a dichroic filter Dg, and a second 1/4 phase plate R2.

【0069】

As a result, the light incident as the illumination light (I) is adjusted to linearly polarized light () by the polarizing plate Pg, then converted to circularly polarized light () by the first phase plate R1 and incident on the dichroic filter Dg. To do.

【0070】

In the dichroic filter Dg, light (C) having an unnecessary wavelength component is reflected, and the wavelength component used is transmitted. The polarization direction () of the light reflected by the dichroic filter Dg is converted by the first 1/4 phase plate R1 into the polarization direction (|) rotated 90 degrees from the transmission axis of the polarizing plate Pg, and this reflected light is converted. It is absorbed by the polarizing plate Pg.

【0071】

Further, the light transmitted through the dichroic filter Dg is converted into linearly polarized light (|) by the second 1/4 phase plate R2 and incident on the image display element 8g.

【0072】

The light (P) reflected by the image display element 8g and whose polarization direction did not change becomes circularly polarized light () again on the second 1/4 phase plate R2, passes through the dichroic filter Dg, and then becomes the first. It is transmitted through the 1/4 phase plate R1 and converted into linearly polarized light in the same polarization direction () as the illumination light (I), and is transmitted through the polarizing plate Pg.

【0073】

The light (P') whose polarization direction is rotated by 90 degrees by the image display element 8g is rotated by 90 degrees (), so that the second phase plate R2, the dichroic filter Dg and the first phase plate R1 Is converted into a polarization direction (|) orthogonal to the illumination light (I) and absorbed by the polarizing plate Pg.

【0074】

Dichroic filter units PDr and PDb with a polarizing plate having the same configuration as G are provided in the optical paths of R and B.

【0075】

Here, the color separation characteristics of the dichroic prism 7 in this embodiment are shown in FIG. 8, and the spectral characteristics of the dichroic filters Dg, Db, and Dr are shown in FIG.

【0076】

In FIG. 8, the cut wavelengths of the dichroic prism 7 are set to λ1 = 495 nm and λ2 = 580 nm, and the view of the figure is the same as that of FIG.

【0077】

Further, in FIG. 9, the dichroic filters Dg, Db, and Dr are bandpass filters Tg having cut wavelengths of 505 nm and 575 nm in the G optical path, edge filters Tb having cut wavelengths of 485 nm in the B optical path, and cuts in the R optical path. An edge filter Tr having a wavelength of 595 nm.

【0078】

As a result, the wavelength region light of 485-505 nm and 575-595 nm is removed from the white light emitted from the light source, and the white light balanced with the color light having high color purity is reproduced.

【0079】

(Fourth Embodiment) FIG. 10 shows the configuration of the projection type image display device according to the fourth embodiment of the present invention. The components common to the first embodiment are designated by the same reference numerals as those of the first embodiment and are replaced with explanations.

【0080】

In this embodiment, the illumination optical system is provided with a color phase filter CF that converts the polarization direction of light in a specific wavelength band by 90 degrees, and the dichroic surface is composed of four triangular prisms and the dichroic surface is crossed in an X shape. It differs from the first embodiment in that the prism 47 is used.

【0081】

Here, the operation of the dichroic prism 47 will be described. In the figure, of the light incident from the first surface 47a, the light reflected by the first dichroic surface 47db is transmitted through the second surface 47c, is transmitted through the dichroic filter unit PDb with a polarizing plate, and is further B light. It leads to the image display element 8b for.

【0082】

The light reflected by the second dichroic surface 47dr passes through the third surface 47b, passes through the dichroic filter unit PDr with a polarizing plate, and then reaches the image display element 8r for R light.

【0083】

The light transmitted through both the first dichroic surface 47db and the second dichroic surface 47dr passes through the fourth surface 47d and passes through the dichroic filter unit PDg with a polarizing plate, and then reaches the image display element 8g for G light. ..

【0084】

The color phase filter CF rotates the polarization direction by 90 degrees in a specific wavelength band (for example, the G band) when light aligned in a certain polarization direction is incident. This is shown in FIGS. 11 (a) and 11 (b).

【0085】

FIG. 11 (a) shows the intensity of the polarization component parallel to the polarization direction of the incident light, and FIG. 11 (b) shows the intensity of the polarization component perpendicular to the incident polarization direction.

【0086】

Since the light having the characteristics shown in FIGS. 11 (a) and 11 (b) is emitted from the color phase filter CF, in the present embodiment, the polarization directions of G and the polarization directions of R and B transmitted through the dichroic prism 7 are defined. Is 90 degrees different. Therefore, as shown in FIG. 12, the transmission axis Qg of the polarizing plate Pg in the polarizing plate-equipped dichroic filter unit PDg provided in the optical path of G and the dichroic filter unit PDr with a polarizing plate provided in the optical paths of R and B. The transmission axes Qr and Qb of the polarizing plates Pr and Pb in PDb are in different directions by 90 degrees.

【0087】

Further, a phase plate may be provided in the optical path of G or R, B, and the polarization direction may be changed to a predetermined direction.

【0088】

As shown here, the polarization directions of the G, R, and B lights are different by 90 degrees, and the light that passes through the dichroic film that constitutes the dichroic prism 7 is configured to pass through the dichroic film as P-polarized light. Therefore, the efficiency in the dichroic film can be made higher.

【0089】

Further, as a configuration different from this embodiment, a color phase filter CF is provided between the optical path prism 6 and the dichroic prism 7, and in the optical path prism 6, each color light is transmitted and reflected in the same polarization direction, and in the dichroic prism 7. May use the P-polarized light component and the S-polarized light component properly depending on the colored light.

【0090】

As described above, in the configuration using the color phase filter CF, not only the dichroic prism composed of the cross prism shown in the present embodiment but also the dichroic prism composed of the 3P prism as shown in the first embodiment has a color separation action. Any configuration can have the effects shown here.

【0091】

(Fifth Embodiment) FIG. 13 shows the configuration of the projection type image display device according to the fifth embodiment of the present invention.

【0092】

In the present embodiment, the light passage in the optical path prism 6 is the same as that in the first embodiment except that the light passage is different from each of the above embodiments. Therefore, the common components are designated by the same reference numerals as those in the first embodiment. Instead of explanation.

【0093】

In the present embodiment, the illumination light that has passed through the lens 5b first passes through the polarizer P and enters the first surface 6b'of the optical path prism 6, and then passes through the second surface 6c'to the dichroic prism 7. Incident.

【0094】

In the dichroic prism 7, the illumination light is separated into R, G, and B color lights, the R and B lights pass through the dichroic filters Tr and Tb, and the G light remains as it is, as in the first embodiment. After incident on each image display element 8r to 8b of each color and modulated, the light of R and B transmitted through the dichroic filters Tr and Tb and the light of G are combined and again from the second surface 6c'of the optical path prism 6. Incident.

【0095】

The image light incident on the optical path prism 6 is totally reflected by the first surface 6b', emitted from the third surface 6a', transmitted through the analyzer A, and then projected by the eccentric projection lens 10.

【0096】

In the present embodiment, the illumination light from the illumination optical system is transmitted to the dichroic prism 7 between the illumination optical system and the dichroic prism 7, and the image light from the dichroic prism 7 is reflected at a reflectance close to 100%. An optical path prism 6 that transmits light toward the eccentric projection lens 10 is provided so that the optical path of the illumination light and the optical path of the image light in the optical path prism 6 and the dichroic prism 7 are different from each other. The optical path of the illumination light and the optical path of the image light can be separated without providing the polarization beam splitter. Moreover, the optical path prism 6 can reflect the image light from the dichroic prism 7 with a reflectance close to 100% and guide it to the eccentric projection lens 10.

【0097】

Therefore, the light utilization efficiency can be improved as compared with the conventional projection type image display device, and a bright display image can be obtained.

【0098】

In the present embodiment, auxiliary optical elements that refract and transmit the illumination light from the illumination optical system are arranged between the optical path prism 6 and the illumination optical system with an air gap with respect to the optical path prism 6. May be good.

【0099】

Further, in the present invention, the arrangement of the image display elements for each color light is not limited to the arrangement described in each of the above embodiments, and may be set arbitrarily.

【0100】

[Effect of the invention]

As described above, according to the first to fifth inventions of the present application, the wavelength band of the colored light that illuminates each image display element is determined by the characteristics of the film such as the dichroic film of the color separation synthetic optical system. Since the image display device is provided with a color adjusting means such as a dichroic filter that narrows the wavelength band of the color light between the color separation synthesis optical system and the image display element, the film characteristics of the color separation synthesis optical system can be obtained from the color light. It is possible to remove the wavelength band component light in the region where the transmission wavelength band is changed to the reflection wavelength band, and it is possible to increase the purity of the color light and expand the range of color reproduction.

【0101】

Further, in general, the wavelength band component light in the region where the film characteristics of the color-resolved synthetic optical system changes from the transmission wavelength band to the reflected wavelength band depends on the difference in the phase characteristics between P-polarized light and S-polarized light in the film of the color-resolved synthetic optical system. It causes the polarization state to be disturbed and the image contrast to be lowered, but this can be improved by providing the color adjusting means as in the present invention.

【0102】

Further, according to the second to fifth inventions of the present application, it is possible to separate the optical path of the illumination light and the optical path of the image light without providing a polarizing beam splitter as in the conventional case. Moreover, since the light guide element reflects the illumination light from the illumination optical system or the image light from the color separation synthetic optical system with a reflectance close to 100% and guides it to the color separation synthetic optical system or the projection optical system, it is conventional. Compared with the projection type image display device, the light utilization efficiency can be improved, and a bright and high-definition display image can be obtained.

【0103】

Further, as in the third and sixth inventions, the reference axis in the color separation synthesis optical system (or the illumination optical system) and the reference axis in the projection optical system are set with respect to the normal of the display surface of the image display element, respectively. If it is set to be tilted, the projection optical system can be miniaturized.

【0104】

By setting the projection optical system as an eccentric optical system having at least one rotationally asymmetric surface or a plurality of optical elements having different rotational symmetry axes, eccentric aberration such as keystone distortion generated by tilting the projection optical system. Can be corrected.

【0105】

Further, when the light guide element is formed in a wedge shape, an auxiliary optical element that refractes and transmits the image light emitted from the light guide element between the light guide element and the projection optical system is air-spaced with respect to the light guide element. By arranging them with a space between them, or by arranging an auxiliary optical element that refractes and transmits the illumination light from the illumination optical system between the light guide element and the illumination system with an air gap with respect to the light guide element. , It is possible to alleviate the aberration generated in the wedge shape.

[Simple explanation of drawings]

[Figure 1]

It is a figure which shows the structure of the projection type image display apparatus which is 1st Embodiment of this invention.

[Figure 2]

It is a partially enlarged view in the projection type image display device of the said 1st Embodiment.

[Fig. 3]

It is a figure explaining the characteristic of the dichroic prism in the said 1st Embodiment.

[Fig. 4]

It is a figure explaining the characteristic of the dichroic filter in the said 1st Embodiment.

[Fig. 5]

It is a figure which shows the structure of the projection type image display apparatus which is 2nd Embodiment of this invention.

[Fig. 6]

It is a figure which shows the structure of the projection type image display apparatus which is 3rd Embodiment of this invention.

[Fig. 7]

It is a figure explaining the optical action of the dichroic filter unit with a polarizing plate in the said 3rd Embodiment.

[Fig. 8]

It is a figure explaining the characteristic of the dichroic prism in the said 3rd Embodiment.

[Fig. 9]

It is a figure explaining the characteristic of the dichroic filter in the said 3rd Embodiment.

[Fig. 10]

It is a figure which shows the structure of the projection type image display apparatus which is 4th Embodiment of this invention.

[Fig. 11]

It is a characteristic diagram of the color phase filter in the said 4th Embodiment.

[Fig. 12]

It is a figure explaining the transmission direction of the polarizing plate in the said 4th Embodiment.

[Fig. 13]

It is a figure which shows the structure of the projection type image display apparatus which is 5th Embodiment of this invention.

[Fig. 14]

It is a figure which shows the structure of the conventional projection type image display apparatus.

[Explanation of symbols]

1 light source 2 reflector 3 integrator 4 Polarization conversion element 5 Condensing optical system 6 Optical path prism 7 Dichroic prism 8r, 8g, 8b image display element 9 Auxiliary prism 10 Eccentric projection lens P-polarizer A detector Reference axis of IL illumination optics Reference axis of PL projection optics Pr, Pg, Pb polarizing plate Tr, Tb, Dr, Dg, Db dichroic filter PDr, PDg, PDb Dichroic filter unit CF color phase filter θ Tilt angle of the reference axis of the illumination optical system (and projection optical system) with respect to the normal of the image display element