HEADLIGHT FOR A MOTOR VEHICLE

Abstract

A headlight for a motor vehicle having at least one light source which emits light during operation of the headlight. A primary optical system has at least one light entry surface for the light emitted by the at least one light source and at least one light exit surface. A secondary optical system, which, during operation of the headlight, projects the light emitted from the at least one light exit surface of the primary optical system into the space outside the motor vehicle where it produces a light distribution which has a horizontal cut-off line and light portions located above the cut-off line in order to implement an OS function (overhead sign function). The headlight being designed such that a portion of the light emitted by the primary optical system is reflected back to the primary optical system by the secondary optical system.

Claims

1. A headlight for a motor vehicle, the headlight comprising: at least one light source that emits light during operation of the headlight; a primary optical system that has at least one light entry surface for the light emitted by the at least one light source, and has at least one light exit surface; and a secondary optical system that, during operation of the headlight, projects the light emitted from the at least one light exit surface of the primary optical system into a space outside the motor vehicle where it produces a light distribution which has a horizontal cut-off line and light portions located above the horizontal cut-off line in order to implement an OS function (overhead sign function), wherein a portion of the light emitted by the primary optical system is reflected back to the primary optical system by the secondary optical system, and wherein the back-reflected portion of the light is reflected by the primary optical system in a direction of the secondary optical system and, after passing through the secondary optical system, is deflected into a region above the cut-off line in order to implement the OS function.

2. The headlight according to claim 1, wherein the primary optical system has a surface that faces the secondary optical system and is designed to reflect the portion of the light, reflected back from the secondary optical system, in the direction of the secondary optical system.

3. The headlight according to claim 2, wherein the surface of the primary optical system, the surface facing the secondary optical system, is oriented such that a normal to the surface forms an angle equal to 0? or not equal to 0? with the horizontal when the headlight is installed in the motor vehicle.

4. The headlight according to claim 2, wherein the surface of the primary optical system, the surface facing the secondary optical system, is oriented such that a direction of propagation of the portion of the light, reflected by the surface in the direction of the secondary optical system, is inclined upwards and/or downwards relative to the horizontal when the headlight is installed in the motor vehicle.

5. The headlight according to claim 1, wherein the surface of the primary optical system, the surface facing the secondary optical system, is provided with a reflective coating.

6. The headlight according to claim 1, wherein the surface of the primary optical system, the surface facing the secondary optical system, is formed flat or curved and/or wherein the surface of the primary optical system, the surface facing the secondary optical system, is provided with a structure, a graininess, or a graining.

7. The headlight according to claim 6, wherein the surface of the primary optical system, the surface facing the secondary optical system, is concave or convexly curved.

8. The headlight according to claim 1, wherein the surface of the primary optical system, the surface facing the secondary optical system, is part of the at least one light exit surface of the primary optical system or corresponds to the at least one light exit surface.

9. The headlight according to claim 1, wherein the surface of the primary optical system, the surface facing the secondary optical system, is not part of the at least one light exit surface of the primary optical system and/or does not correspond to the at least one light exit surface.

10. The headlight according to claim 9, wherein the surface of the primary optical system, the surface facing the secondary optical system, is formed on a base or on a base plate of the primary optical system.

11. The headlight according to claim 1, wherein the secondary optical system has a light entry surface for the light emitted from the at least one light exit surface of the primary optical system and a light exit surface for the light entering through the light entry surface.

12. The headlight according to claim 11, wherein the light entry surface of the secondary optical system is designed to reflect the portion of the light, emitted by the primary optical system, back to the primary optical system.

13. The headlight according to claim 11, wherein the secondary optical system is designed so that the portion of the light reflected by the surface of the primary optical system, the surface facing the secondary optical system, in the direction of the secondary optical system enters the secondary optical system through the light entry surface and then exits the secondary optical system through the light exit surface.

14. The headlight according to claim 1, wherein the at least one light source is a light-emitting diode or laser diode, or wherein a plurality of light-emitting diodes and/or laser diodes serving as light sources are provided.

15. The headlight according to claim 1, wherein the primary optical system has a plurality of light entry surfaces, wherein at least one of the light sources is assigned to each of the light entry surfaces so that the light emitted by the light source enters the assigned light entry surface.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0019] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawing which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein the sole FIGURE shows a schematic side view of a headlight of the invention with light beams drawn in by way of example.

DETAILED DESCRIPTION

[0020] The headlight shown comprises a plurality of light sources 1 which emit light 2 during operation of the headlight. Light sources 1 are designed as light-emitting diodes (LEDs). Alternatively, laser diodes can be used instead of the light-emitting diodes.

[0021] The headlight further comprises a primary optical system 3, which has a plurality of collimating optics 4, one of which is assigned to each of light sources 1. For light 2 of one of light sources 1, each of collimating optics 4 has a light entry surface 5 and a light exit surface 6. It is also possible that, for example, only one common light exit surface is provided for all collimating optics 4. Primary optical system 3 also has a base plate 7 on which collimating optics 4 are arranged.

[0022] The headlight further comprises a secondary optical system 8, which is designed as a single lens in the illustrated exemplary embodiment. The lens can be designed, for example, as a plano-convex lens. It is certainly possible to provide a more complex secondary optical system, for example, one formed of multiple components.

[0023] Secondary optical system 8, designed as a lens in the illustrated exemplary embodiment, has a light entry surface 9 for the light 2 emitted from the at least one light exit surface 6 of primary optical system 3 and a light exit surface 10 for the light entering through light entry surface 9.

[0024] During operation of the headlight, the light 2, emitted from the at least one light exit surface 6 of primary optical system 3, is projected by secondary optical system 8 into the space outside the motor vehicle so that a light distribution is generated there which has a horizontal cut-off line and light portions located above said cut-off line in order to implement an OS function.

[0025] To implement this OS function, a portion 11 of light 2 is used, which is reflected back from light entry surface 9 of secondary optical system 8. This portion 11 of light 2 strikes a surface 12 of primary optical system 3, said surface facing secondary optical system 8. This surface 12 is the front face of base plate 7 of primary optical system 3, which surface faces secondary optical system 8. A portion 13 of back-reflected portion 11 is again reflected from surface 12 in the direction of secondary optical system 8. This portion 13 enters secondary optical system 8 through light entry surface 9 and exits slightly upwards through light exit surface 10.

[0026] It is entirely possible to envisage using a different surface of primary optical system 3, instead of the front face of base plate 7, to reflect portion 11 reflected back by secondary optical system 8. For example, at least one surface on one or more of collimating optics 4 can be used. In particular, one or more of the light exit surfaces 6 of collimating optics 4 can also be used to reflect portion 11 of light 2 reflected back by secondary optical system 8.

[0027] Surface 12 of primary optical system 3, said surface provided for reflecting portion 11 of light 2 reflected back by secondary optical system 8, can be oriented such that the normal to surface 12 forms an angle equal to 0? or not equal to 0? with the horizontal when the headlight is installed in the motor vehicle. For example, surface 12 of primary optical system 3, said surface facing secondary optical system 8, can be oriented such that the direction of propagation of portion 13 of light 2, which portion is reflected by surface 12 in the direction of secondary optical system 8, is inclined downwards relative to the horizontal when the headlight is installed in the motor vehicle. As a result, this portion 13 of the light is deflected upwards as it passes through secondary optical system 8, so that it reaches a region above the cut-off line. Alternatively, surface 12 of primary optical system 3, said surface facing secondary optical system 8, can also be oriented such that the direction of propagation of portion 13 of light 2 reflected by surface 12 in the direction of secondary optical system 8 is inclined upwards relative to the horizontal when the headlight is installed in the motor vehicle.

[0028] It is possible that surface 12 of primary optical system 3, said surface provided for reflecting portion 11 of light 2 reflected back by secondary optical system 8, is provided with a reflective coating. This allows the reflectance of the surface of the primary optical system, said surface facing the secondary optical system, to be increased, so that a larger portion 13 of back-reflected light 2 can be used to generate the OS values.

[0029] In the illustrated exemplary embodiment, surface 12 of the primary optical system, provided for reflecting portion 11 of light 2 reflected back by secondary optical system 8, is concavely curved. Alternatively, surface 12 can also be formed flat or convexly curved. By suitably shaping surface 12, provided for reflecting portion 11 of light 2 reflected back by secondary optical system 8, portion 13 of light 2 can be suitably shaped, so that the shaped and reflected portion 13 of light 2 can be used to generate the desired OS values.

[0030] 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.