Headlamp for cars according to projection principle

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State of the art

The invention relates to a headlight for vehicles according to the light projection principle which comprises a reflector, a light source, a lens, through which the light emitted by the light source and reflected by the reflector passes, and an element. which allows at least part of the light to pass and which surrounds the lens on at least part of its periphery, element which at least locally has optical profiles and through which passes and is concentrated the light emitted by the light source and which cannot be picked up by the reflector, the light reflected by the reflector and which has passed through the lens , exhibiting an upper limit of chiaroscuro.

Such a lighthouse is known from document DE32 18 703-A1. This headlight has a reflector, a light source and a lens through which the light reflected by the reflector passes. In addition, the headlight has an element which allows light to pass and surrounds the lens at least on a part of its periphery, element which has optical profiles and through which can pass and can be concentrated the light emitted by the light source and that cannot be picked up by the reflector. The element presents as optical profiles prisms by which the light which passes through is deflected.

By means of this configuration of the element, the illuminating surface of the headlight is enlarged relative to the surface of the lens when the light source is turned on, so that the headlight does not cause glare or cause glare. only low subjective glare. The quantity of light which is emitted by the light source and which passes through the element, however, is not sufficient in some cases to obtain sufficient illumination of the element. When the light source is turned off, the element appears dark and the headlight has an undesirable inhomogeneous appearance. In the case of headlights which operate on the principle of projection of light, the light emitted by these headlights has a precise upper limit characteristic of chiaroscuro, which is advantageous in order to avoid dazzling oncoming traffic, but however has the drawback that objects arranged in height, such as for example signposts or traffic signs, are not illuminated or are not sufficiently illuminated.

Advantages of the invention

The headlight according to the invention is characterized in that it has at least one additional light source which serves to produce a position light, arranged in such a way that the light emitted by this source passes at least in part through the item.

The headlight according to the invention thus has the advantage that, thanks to the use of the light also emitted by the additional light source serving for the production of the delimiting light, the lighting of the element is improved.

According to other characteristics of the invention:

• at least one of the additional light sources is arranged on a border zone which protrudes on the front edge of the reflector which is turned in the direction of exit of the light, perpendicular to the direction of exit of the light, • the optical profiles of the element are made in the shape of a ring to form at least one Fresnel lens, • the ring-shaped optical profiles are formed at least approximately concentrically to at least one of the additional light sources, • the ring-shaped optical profiles are formed at least approximately concentrically to the light source. light, • on at least part of the path of the rays of the light which has passed through the element is placed an at least partly reflecting layer which is turned in the direction of exit of the light, • at least part of the path of the rays of the light which has passed through the element is placed other optical profiles which deflect the light which passes through them, and • this illuminates an area in front of the vehicle above the chiaroscuro limit of the light reflected by the reflector and which has passed through the lens.

Drawings

The present invention will be described below in more detail on the basis of several exemplary embodiments shown in the accompanying drawings in which:

• Figure 1 shows, in vertical longitudinal section, a headlight according to a first embodiment;

• Figure 2 shows the lighthouse in a view in the direction of arrow II of Figure 1, • Figure 3 shows the lighthouse in a view in the direction of arrow II of Figure 1, corresponding to an exemplary embodiment modified;

• Figure 4 shows the lighthouse according to a second embodiment in a vertical longitudinal section;

• Figure 5 shows the headlight corresponding to a modified embodiment, in a vertical longitudinal section; and • Figure 6 shows a measurement screen arranged in front of the lighthouse and illuminated by the light emitted by the lighthouse.

Description of the implementation examples

A headlight, shown in Figures 1 to 5, for vehicles such as in particular motor vehicles, is constructed according to the principle of projection of light and serves to produce at least the light of the low beam of the vehicle. The headlight has a reflector 10 made of plastic or metal, in which is inserted a light source 12 placed in the region of its top. The light source 12 may be an incandescent lamp, a gas luminescent lamp, or other suitable lamp. After the reflector 10 seen in the direction of the exit of the light, a lens 16 made of glass or of plastic material has been placed, which may for example have a flat side 18 turned towards the reflector 10 and, opposite, a curved side. convex 20. The lens 16 is held in a support member 22 which can be connected to the leading edge 24 of the reflector 10 which is rotated in the direction of exit 14 of the light. The reflector 10 and the lens 16 can be arranged in a housing 15 which has a light exit opening covered by a lens 17 made of glass or plastic material transparent to light. The cover glass 17 can be formed smoothly so that the light passes through without being influenced or alternatively the glass can at least locally have optical elements by which the light passing through is deflected and for example scattered. .

Light emitted by light source 12 is reflected by reflector 10 as a converging beam of light which passes through lens 16 and in so doing is deflected. The lens 16 operates in this case as a converging lens and the light which passes through is deflected by it towards the optical axis 11 of the reflector 10. The reflector 10 may for example have the shape of an ellipsoid, at least in an approximate manner, a shape similar to that of an ellipsoid or a shape determined digitally, deduced from the characteristic of the light beam to be reflected by the reflector 10. Between the reflector 10 and the lens 16, a screen 26 can be provided which does not allow light to pass, situated substantially below the optical axis 11, and along which only a part of the light beam reflected by the lens can pass. reflector 10. The beam of light which passes along the screen 26 receives a chiaroscuro limit which is determined by the upper edge of the screen 26, which limit is reproduced by the lens 16 in the form of the light limit - dark of the beam of light from the low beam coming out of the headlight. Alternatively, the screen 23 may also not exist, when the shape of the reflector 10 is determined in such a way that the light beam reflected by it already has the necessary chiaroscuro limit which is reproduced by the reflector. lens 16.

The reflector 10 has a cross section Q1 on its front edge 24, and the lens 16 has a cross section Q2 smaller than this cross section Q1. The support member 22 may have one or more struts 28 which extend, starting from the leading edge 24 of the reflector 10, almost to the lens 16 where they may for example be connected to each other by a section of annular shape 30 in which the lens 16 is held by its edge. The light which is emitted by the light source 12 and which cannot be picked up by the reflector 10 can pass through openings 32 which remain between the spacers 28. The spacers 28 are preferably made as narrow as possible. , to keep large openings 32 between them, so that a large part of the light emitted by the light source 12 can therefore pass through them. As a variant the support element 22 can also consist, at least in part, of a material which allows light to pass, for example a plastic or glass, so that the light emitted by the light source 12 can pass through this matter. In this case, the support element 22 does not need to have openings.

The reflector 10 has, on its front edge 24 which is turned in the direction of the exit of the light, a border zone 34 overhanging perpendicularly to the direction of exit 14 of the light, which border zone can be connected by integral with reflector 10 or be joined to reflector 10 as a separate piece. The border zone 34 can also be joined to the support element 22 of the lens 16 or be formed integrally therewith. The border zone 34 can be arranged in the lateral direction next to the reflector 10, or even above or below this reflector 10. In the case of the exemplary embodiments which have been shown, the border zone 34 is arranged above the reflector 10. In the border zone 34 an additional light source 36 has been inserted which serves to produce the position light prescribed by law. The contours of the vehicle must be marked by the position light, and there are legal requirements for this with regard to the intensity of the necessary lighting and its visibility in different directions. The edge area 34 may be reflective like the reflector 10, and have a planar shape or a concave curved shape, to reflect the light emitted by the additional light source 36 in the direction of the exit 14 of the light. light. However, provision can also be made for the border zone 34 not to be produced in a reflective manner, for only the direct light emitted by the additional light source 36 to be used. incandescent lamp, for example of the W5W or H6W type, or a lamp of another type of construction.

At least one element 40 is also provided which surrounds the lens 16 over at least part of its periphery, element 40 which is shown in FIG. 1 and in FIG. 2 according to a first exemplary embodiment. The element 40 surrounds the lens 16 over its entire periphery and is made of a material which allows light to pass, such as, for example, a plastic material or glass. The element 40 has, in its central zone, an opening 41 in which the lens 16 is placed. The lens 16 and the element 40 can also be made in one piece. The element 40 is at least locally, but preferably over its entire extent, formed in the form of a Fresnel lens, and in this case has several concentric optical profiles 42, of annular shape. The optical profiles 42 can be arranged, as shown in Figures 1 and 2, on the side of the element 40 which is turned in the direction opposite to the direction 14 of light output, or also on the side of the element 40 which is rotated in the direction of exit of the light. The optical profiles 42 are for example formed in the form of notches and the light which passes through the element 40 is deflected by these profiles in the direction of the optical axis 11 to be in this way concentrated. The element 40 is arranged in such a way that the light emitted by the light source 12, and which cannot be picked up by the reflector 10, as well as the light which is emitted by the additional light source 36 , pass through this element. The optical profiles 42 can be constituted for example in such a way that the light emitted by the light sources 12 and 36, after its passage through these profiles is directed at least approximately parallel to the optical axis 11.

In the case of the first embodiment, the optical profiles 42, in the form of rings, as shown in FIG. 2, are arranged approximately concentrically to the other light source 36 on the element 40 , and to extend over the entire element 40. The element 40 has for example a round shape, the shape of the element 40 can however be chosen in any other way, and be for example oval or polygonal, respectively according to the aspect which the headlight must present. Provision can also be made for it to surround the lens 16 only over part of its periphery, and for example is only disposed laterally only next to the lens 16 or only above and / or below the lens 16.

Element 40 may be arranged, as shown in Figure 1, in such a manner that it has approximately the same distance from reflector 10 as lens 16 in the direction of the axis. Optical 11. As a variant, however, the element 40 may also have a different distance from the reflector 10 than the lens 16 in the direction of the optical axis 11, and in this way be arranged offset relative to the lens 16 . The element 40 as shown in Figures 1 to 5, can be formed, also in a planar manner or, as a variant, be bent at will in a concave or convex manner. The light emitted by the two light sources 12 and 36 passes through the element 40, so that sufficient illumination of the element 40 is obtained.

According to a development of the lighthouse, it is possible to have at least part of a reflecting layer 44 on at least part of the path of the rays of the light which passes through the element 40. In the case of the lighthouse according to the first embodiment, that 1'on shown in Figures 1 and 2, the layer which is in the form of the coating 44, is deposited at least locally on the side of the element 40 which is rotated in the direction 14 of light output. The coating 44 can be produced in such a way that it allows light to pass, while then being disposed only locally on the element 40, to allow partial passage of the light emitted by the light sources 12 and 36. The coating 44 can in this case be produced in the form of lines or rings.

As a variant, the coating 44 can also be produced in such a way that it partly allows light to pass and is partly reflective. In this case the entire surface of the element 40 may be covered by the coating 44, or also only part of this surface. The light emitted by the light sources 12 and 36 can in this case pass partly through the coating 44, while the light arriving from outside on the coating 44 is partly reflected. The coating 44 is preferably made of metal, for example aluminum, and can be placed on the element 40 by means of a known method, for example by vacuum metallization, by spraying, by lacquering, by printing or by stamping.

The light-passage permeability of the coating 44 can be varied by means of its thickness, its light-passage permeability decreasing as its thickness increases. In order to obtain a partial permeability of the coating 44 to the passage of light, it is produced with a small thickness, while in order to obtain a high degree of reflection it is produced with a correspondingly greater thickness. The coating 44 allows the passage, at least in part, of the light emitted by the light sources 12 and 36, through the element 40, when the headlight is on while, when the headlight is off, the light which enters it from the outside is reflected by the coating 44 so that the headlight in this way exhibits a shiny appearance in the area of ​​the element 40.

FIG. 3 shows the lighthouse according to an embodiment modified with respect to the first exemplary embodiment according to FIGS. 1 and 2, the basic construction of the lighthouse remaining the same as that of the first exemplary embodiment. In the case of the modified embodiment, the dis2777064 position of the optical profiles 42 which form the Fresnel lens, is only modified with respect to the first exemplary embodiment in such a way that these profiles extend in at least an annular shape. approximately concentrically to the optical axis 11 of the reflector 10 and, in this way, to the light source 12. The optical profiles 42, of annular shape which serve to form the Fresnel lens, may, by deviating from the first example embodiment, according to FIG. 2 and according to the modified embodiment of FIG. 3, also be arranged otherwise to will.

In the case of a development of the lighthouse according to a second exemplary embodiment, shown in FIG. 4, the basic construction of the lighthouse with the reflector 10, the light source 12, the lens 16 and the screen 26, remains unchanged. compared to the first exemplary embodiment. In addition, over at least a part of the path of the rays of the light passing through the element 50, provision is made for other optical profiles 56 through which the light is deflected upwards. The other optical profiles 56 are arranged on the side of the element 50 which is turned in the direction of exit 14 of the light. On the side of the element 50 which is turned in the opposite direction to the direction of exit 14 of the light, the optical profiles 52 of annular shape which constitute the Fresnel lens have been arranged. The other optical profiles 56 can be formed, for example, in the form of lenses which extend more or less horizontally, diffusing from one side upwards.

FIG. 6 shows a measuring screen 80 disposed at a certain distance from the headlight, which measuring screen is illuminated by the light emitted by the headlight. The horizontal median plane of the measurement screen 80 is designated by the reference HH and the vertical median plane is designated by the reference W. The horizontal median plane HH and the vertical median plane VV intersect at the point HV. The measuring screen 80 is illuminated, in a zone 82, by the light reflected by the reflector 10 and which passes along the screen 26 through the lens 16. The zone 82 is limited upwards ίο by the limit chiaroscuro produced by the screen 26. In the case of the exemplary embodiment shown, the lighthouse is designed for right-hand traffic and the chiaroscuro limit present, on the side of the traffic in the opposite direction, that is to say from the left side of the measurement screen 80, a section 84 which extends approximately horizontally below the horizontal midplane HH. On the side of normal direct circulation, therefore on the right side of the screen 80, the chiaroscuro limit has a section 86 which, starting from the horizontal section, towards the right edge of the measurement screen 80, goes increasing until beyond the horizontal median plane HH. According to a variant, the chiaroscuro limit on the side of normal direct circulation may also have another approximately horizontal section which is arranged higher than the horizontal section 84. The distribution of light intensities in zone 82 is predefined by legal regulations, the highest light intensities being in a zone below point HV. Above the chiaroscuro limit 84, 86, the measuring screen 80 is not illuminated at all or is illuminated only very weakly by the beam of light reflected by the reflector 10 and which passes along it. screen 26 through lens 16.

The measurement screen 80 is illuminated, in an area 88 disposed at a certain distance above the chiaroscuro limit 84, 86, by the light which has passed through the element 50 and which has been deflected towards the sky. top by the other optical profiles 56. The light which passes through the element 50 causes, in zone 88, a lighting such as are respected the legal prescriptions as regards the necessary values ​​of the minimum lighting intensity and as for the highest values ​​of the intensity d maximum lighting permitted.

By way of example, in regulation 20 of the European Economic Community which is in force in Europe, a measurement point B50L is defined at which the lighting intensity must be able to reach a maximum of 0.4 Lux, in order to avoid dazzling oncoming traffic. In respec2777064 n

Both the regulatory requirements, the distribution of the lighting intensity can be freely chosen in zone 88. The distribution of the lighting intensity can for example be chosen such that an area 90 of the measurement screen which is directly above the chiaroscuro limit 84, 86 and which extends e.g. up to about 2 degrees above the horizontal midplane HH and below about 4 degrees on both sides of the vertical midplane W, is only weakly illuminated by light passing through element 40. The zone 88 which connects upwards and laterally to the zone 90 extends for example vertically upwards to approximately 4 degrees above the horizontal median plane HH and laterally on both sides of the vertical median plane W up to approximately eight degrees, being brighter than zone 90.

When, in the case of the previously described development of the lighthouse according to the second exemplary embodiment, there is also provided, with the other optical profiles 56, a coating 54 at least partly reflecting, it can be placed by way of example on the faces of the other optical profiles 56 which are turned in the direction of exit 14 of the light.

FIG. 5 shows the headlight in an embodiment modified with respect to the embodiment according to the second embodiment, shown in FIG. 4. In the case of the modified embodiment according to FIG. 5, there is provided on at least part of the path of the spokes which are passed through the element 60, a glass 63 on which are arranged, at least locally, optical profiles 66 by which, like the light which is passed through the other optical profiles 56 of the element 50, the light is deflected upwards in such a way that it illuminates the area 88 of the screen measuring 80. The optical profiles 66 can be arranged on the side of the lens 63 which turns in the direction of exit 14 of the light, or in the opposite direction of the direction of exit 14 of the light. The element 60 only needs to present the optical profiles 62 which serve to form the Fresnel lens and which can be arranged on the side of the element 60 which is turned in the direction of exit 14 of the light, or in the direction opposite to the direction of exit 14 of the light. On the side of the lens 63 which is turned in the direction of exit 14 of the light, it is possible to deposit a coating 64 produced as the coating 44 which has been described above in the case of the first exemplary embodiment. The glass 63 has, in its central zone, an opening 67 through which the light which has passed through the lens 16 can pass without being influenced. According to a variant, the lens 63 may also extend over the path of the rays of the light which has passed through the lens 16, the lens 63 not however having optical profiles 66 in this zone.

In the case of another modified embodiment of the headlight, the optical profiles 76 by which the light which has passed through the element 40 or 60 has been deflected upwards to illuminate the area 88 of the measurement screen 80, are arranged on the cover glass 17 of the lighthouse. The ice 63 may in this case not exist, and the element 40 or 60 only needs to have optical profiles 42 or 62 to form the Fresnel lens. The optical profiles 76 are only arranged in areas of the cover glass 17 through which the light which has passed through the lens 16 does not pass.