LIGHTING DEVICE FOR A VEHICLE, IN PARTICULAR A HEADLIGHT

Abstract

A lighting device for a vehicle, in particular a headlight, including a light source, from which light emerges in operation of the lighting device, a collimation optical system having an incident face and an emergent face, which the light emerging from the light source passes through, a projection optical system having a first array of lenses and a second array of lenses, wherein the light emerging from the collimation optical system first passes through the first array of lenses and after that through the second array of lenses, as well as a diaphragm, which the light passes through, wherein the diaphragm is arranged in front of the first array of lenses, so that in operation of the lighting device the light does not strike the first array of lenses until after passing through the diaphragm.

Claims

1. A lighting device for a vehicle, in particular a headlight, the lighting device comprising: a light source from which light emerges in operation of the lighting device; a collimation optical system having an incident face and an emergent face, which the light emerging from the light source passes through; a projection optical system having a first array of lenses and a second array of lenses, wherein the light emerging from the collimation optical system first passes through the first array of lenses and after that through the second array of lenses; and a diaphragm, which the light passes through, wherein the diaphragm is arranged in front of the first array of lenses so that in operation of the lighting device the light does not strike the first array of lenses until after passing through the diaphragm.

2. The lighting device according to claim 1, wherein the diaphragm is arranged at the collimation optical system.

3. The lighting device according to claim 2, wherein the diaphragm is arranged on the incident face of the collimation optical system or is vapor-deposited on the incident face.

4. The lighting device according to claim 2, wherein the first array of lenses generates a multiplicity of intermediate images of the diaphragm in the space between the two arrays of lenses.

5. The lighting device according to claim 4, wherein the second array of lenses projects the intermediate images into the space outside the vehicle, in particular at infinity, when the lighting device is in the installed state in the vehicle.

6. The lighting device according to claim 1, wherein the two arrays of lenses are formed on a substrate, wherein the first array of lenses is arranged on the incident face and the second array of lenses on the emergent face of the substrate.

7. The lighting device according to claim 1, wherein the lenses of at least one of the two arrays or the lenses of both arrays are designed as cylindrical lenses.

8. The lighting device according to claim 7, wherein the cylindrical lenses are arranged adjacent to one another in the horizontal direction and the cylinder axes of the cylindrical lenses extend in the vertical direction when the lighting device is in the installed state in the vehicle.

9. The lighting device according to claim 1, wherein the lenses of at least one of the two arrays or the lenses of both arrays are designed as lenses that have a refractive power in two directions substantially perpendicular to one another and to the central direction of propagation of the light.

10. The lighting device according to claim 9, wherein the lenses are spherical in design.

11. The lighting device according to claim 9, wherein at least two or all lenses of the second array have radii of curvature that differ from one another or focal lengths that differ from one another.

12. The lighting device according to claim 1, wherein the light source includes at least one light-emitting diode and/or at least one laser diode.

13. The lighting device according to claim 1, wherein the lighting device includes a at least two light sources as well as at least two collimation optical systems and a projection optical system or at least two projection optical systems, which are each arranged adjacent to one another in the horizontal direction when the lighting device is in the installed state in the vehicle.

14. The lighting device according to claim 13, wherein a collimation optical system and the projection optical system or one of the projection optical systems are associated with each one of the light sources in such a manner that the light emerging from the light source passes through the associated collimation optical system and the projection optical system or the associated projection optical system sequentially.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0017] FIG. 1 is a top view of a first embodiment of a lighting device according to the invention;

[0018] FIG. 2 is a side view of the lighting device according to FIG. 1;

[0019] FIG. 3 is a perspective view of a second embodiment of a lighting device according to the invention;

[0020] FIG. 4 is a top view of a third embodiment of a lighting device according to the invention;

[0021] FIG. 5 is a side view of the lighting device according to FIG. 4;

[0022] FIG. 6 is a schematic illustration of images of different sizes from differently shaped lenses;

[0023] FIG. 7 is a top view of a fourth embodiment of a lighting device according to the invention.

DETAILED DESCRIPTION

[0024] The embodiment of a lighting device according to the invention depicted in FIG. 1 and FIG. 2 includes a light source 1, represented only schematically, from which light 2 emerges. The light source 1 can have at least one light-emitting diode and/or at least one laser diode.

[0025] The lighting device additionally includes a collimation optical system 3 having an incident face 4 and an emergent face 5, which the light 2 emerging from the light source 1 passes through sequentially. The lighting device additionally includes a diaphragm 6, which is arranged on the incident face 4 of the collimation optical system 3. The diaphragm 6 can be vapor-deposited on the incident face 4. The diaphragm 6 can have a rectangular aperture whose lower edge can define a cutoff line in the light distribution generated in the space outside the vehicle.

[0026] The lighting device additionally includes a projection optical system 7, which includes a first array 8 of lenses 9 and a second array 10 of lenses 11. In this design, the light emerging from the collimation optical system 3 passes first through the first array 8 of lenses 9 and after that through the second array 10 of lenses 11.

[0027] The lenses 9, 11 of the first and second arrays 8, 10 are each designed as cylindrical lenses. The cylindrical lenses are arranged adjacent to one another in the horizontal direction when the lighting device is in the installed state in the vehicle, wherein the cylinder axes of the cylindrical lenses extend in the vertical direction. The lenses 9, 11 of the first and second arrays 8, 10 thus only affect the horizontal direction.

[0028] The first array 8 of lenses 9 generates a multiplicity of intermediate images of the diaphragm 6 in an image plane 12 in the space between the two arrays 8, 10. The second array 10 of lenses 11 projects the intermediate images into the space outside the vehicle at infinity when the lighting device is in the installed state in the vehicle. Consequently, the illumination in the space outside the vehicle can be controlled in the horizontal direction in a targeted manner by the cylindrical lenses. The distribution in the vertical direction is determined by the divergence of the light source 1, the diaphragm 6, and the collimation optical system 3.

[0029] FIG. 3 shows an embodiment in which three light sources 1 as well as three collimation optical systems 3 and a projection optical system 7 are provided, wherein the light sources 1 and the collimation optical systems 3 are each arranged adjacent to one another in the horizontal direction when the lighting device is in the installed state in the vehicle. In this design, a collimation optical system is associated with each one of the light sources 1 in such a manner that the light 2 emerging from the light source 1 passes through the associated collimation optical system and then through the projection optical system 7. Here, the lenses 9, 11 of the first and second arrays 8, 10 of the projection optical system 7 are designed as cylindrical lenses whose cylinder axes extend in the vertical direction, as in the first embodiment according to FIG. 1 and FIG. 2.

[0030] Instead of one common projection optical system 7 for all of the light sources 1 and collimation optical systems 3, it is also possible for three projection optical systems 7 to be provided that are associated in each case with the individual light sources 1 and collimation optical systems 3.

[0031] The third embodiment depicted in FIG. 4 and FIG. 5 corresponds largely to the first embodiment depicted in FIG. 1 and FIG. 2. In contrast thereto, the lenses 9, 11 of the arrays 8, 10 in the embodiment according to FIG. 4 and FIG. 5 are not designed as cylindrical lenses, but instead as lenses 9, 11 that have a refractive power in both the horizontal direction and the vertical direction. For example, the lenses 9, 11 are spherical lenses. As a result, the lenses 11 of the second array 10, in particular, can control the illumination in the space outside the vehicle in the horizontal and vertical directions in a targeted manner.

[0032] In the embodiment according to FIG. 4 and FIG. 5, at least two, in particular all, lenses 11 of the second array 10 have radii of curvature that differ from one another or focal lengths that differ from one another. In this design the radius of curvature, and thus the focal length, of the lenses 11 located further toward the bottom in FIG. 5 is larger than the radius of curvature, and thus the focal length, of the lenses 11 located further toward the top in FIG. 5. For example, the radius of curvature of the topmost lens 11a in FIG. 5 is significantly smaller than the radius of curvature of the bottommost lens 11g in FIG. 5.

[0033] FIG. 6 schematically illustrates that different-sized images of the light 2 striking the lenses 11 or of the intermediate images generated in the plane 12 are generated by different radii of curvature. For example, a small image, such as the image labeled 13a in FIG. 6, could be generated by a lens with a small radius of curvature such as the lens 11a. Moreover, a large image, such as the image labeled 13g in FIG. 6, could be generated by a lens with a large radius of curvature such as the lens 11g.

[0034] By this means, the result can be achieved, in particular, that the images 13a, 13g of the intermediate images are enlarged in the lower end region of the light distribution generated in the space outside the vehicle, so that a connection to a vicinity lighting generated in front of the vehicle is produced.

[0035] FIG. 7 shows the beam path of the light 2 through an embodiment in which three light sources 1 as well as three collimation optical systems 3 and a projection optical system 7 are provided, wherein the light sources 1 and the collimation optical systems 3 are each arranged adjacent to one another in the horizontal direction when the lighting device is in the installed state in the vehicle. In this design, a collimation optical system is associated with each one of the light sources 1 in such a manner that the light 2 emerging from the light source 1 passes through the associated collimation optical system and then through the projection optical system 7. Here, the lenses 9, 11 of the first and second arrays 8, 10 of the projection optical system 7 are designed as lenses 9, 11 that have a refractive power in both the horizontal direction and the vertical direction, as in the third embodiment according to FIG. 4 and FIG. 5.

[0036] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.