Lighting device for a vehicle that enables a vertical soft transition of light intensity in the near field and/or far field of the light distribution

Abstract

A lighting device for a vehicle, in particular headlights for a vehicle, having a plurality of light sources, from which light is emitted during operation of the lighting device, projection optics for projecting the light, and a generator for generating a light distribution in the exterior of the vehicle, which has a soft transition in the vertical direction from a central region to the near field and/or the far field of the light distribution. The generator has a plurality of converters which change the wavelength spectrum of the light emitted from the light sources. The lighting device being designed in such a way that during operation of the lighting device, at least one first region of at least one of the converters is subjected to a greater luminous flux density of the light emitted from the light sources as a second region of the at least one converter.

Claims

1. A lighting device for a vehicle, in particular headlights for a vehicle, the lighting device comprising a plurality of light sources from which light is emitted when the lighting device is operated; projection optics for projecting the light emitted from the light sources into an exterior space of the vehicle; and generator for generating a light distribution in the exterior space of the vehicle, which has a soft transition in the vertical direction from a central region to the near field and/or to the far field of the light distribution, the generator for generating a light distribution comprising a plurality of converters that change a wavelength spectrum of the light coming from the light sources, wherein the lighting device is configured such that during operation of the lighting device, at least one first region of at least one of the converters is subjected to a greater luminous flux density of the light emitted from the light sources than a second region of the at least one converter.

2. The lighting device according to claim 1, wherein the at least one first region and the at least one second region are arranged side by side in a direction which corresponds to the vertical direction in the light distribution.

3. The lighting device according to claim 1, wherein the light sources are arranged next to one another in two mutually vertical directions so that they form a matrix arrangement.

4. The lighting device according to claim 1, wherein the light sources are light emitting diodes.

5. The lighting device according to claim 1, wherein at least one of the converters is formed such that when the light emitted from one of the light sources is incident on a converter, and wherein a first portion of the light is converted into light with a different wavelength by the converter and a second portion of the light passes through the converter such that overall a substantially white light impression emerges.

6. The lighting device according to claim 1, wherein the light emitted from each of the light sources at least partially is incident on one of the converters.

7. The lighting device according to claim 1, wherein each of the light sources is assigned to one of the converters such that the light emitted from the light source is incident on the associated converter.

8. The lighting device according to claim 1, wherein at least one first converter has a greater extension than at least one second converter, the extension of the first converter in the direction being greater, which corresponds to the vertical direction in the light distribution.

9. The lighting device according to claim 8, wherein the extension of the first converter in the direction (Y), which corresponds to the vertical direction in the light distribution, is more than twice as great as the extension of the second converter) in the direction (Y), which corresponds to the vertical direction in the light distribution.

10. The lighting device according to claim 8, wherein the at least one first converter is arranged asymmetrically with respect to the associated light source, or wherein the at least one second converter is arranged symmetrically to the associated light source.

11. The lighting device according to claim 7, wherein at least one of the converters at least partially surrounds the associated light source.

12. The lighting device according to claim 11, wherein at least one of the converters is designed as a potting compound.

13. The lighting device according to claim 7, wherein at least one of the converters is at least partially spaced apart from the associated light source.

14. The lighting device according to claim 1, wherein at least one of the light sources is surrounded by lateral boundaries.

15. The lighting device according to claim 14, wherein the lateral boundaries between the light source associated with at least one first converter are at least partially at a greater distance than the lateral boundaries to the light source associated with the at least one second converter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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:

(2) FIG. 1 is a side view of a lighting device according to the invention;

(3) FIG. 2 is a front view of the lighting device according to FIG. 1;

(4) FIG. 3 is a plan view of the light sources of the lighting device according to FIG. 1;

(5) FIG. 4 is a detail of FIG. 3;

(6) FIG. 5 is a side view of a detail of the light sources according to FIG. 3 with light emitted from them;

(7) FIG. 6 is a side view of a detail of the light sources according to FIG. 3 with an illustration of the luminous flux and the control of individual light sources.

(8) FIG. 7 is a side view of a lighting device according to the prior art;

(9) FIG. 8 is a front view of the lighting device according to FIG. 7;

(10) FIG. 9 is a plan view of the light sources of the lighting device according to FIG. 7;

(11) FIG. 10 is a detail of FIG. 9; and

(12) FIG. 11 is a side view of a detail of the light sources according to FIG. 9 with an illustration of the luminous flux and the control of individual light sources.

DETAILED DESCRIPTION

(13) The exemplary embodiment of a lighting device according to the invention shown in FIGS. 1 to 6 comprises a plurality of light sources 11 which are arranged next to one another in a matrix arrangement in two mutually perpendicular directions (cf., for example, FIG. 4). The light sources 11 can in particular be embodied as light emitting diodes which emit blue light essentially in the Z direction of the coordinate systems shown.

(14) A converter 12 is arranged in front of each of the light sources 11 in the Z direction and converts a part of the light 13 emitted from the light sources 11 into yellow light, for example, in a manner known per se, so that overall an essentially white light impression is produced. The converter 12 can surround the light source 11 assigned to it. It can surround the light source 11 in particular as a potting compound. Alternatively, the converter 12 can also be spaced apart from the associated light source 11.

(15) The lighting device further comprises projection optics 14, having two lenses 15, 16 successively arranged in the direction of extension of the light 13 emitted from the light sources 11 or in the Z direction in FIG. 1. Due to the elimination of primary optics as in the prior art described in FIGS. 7 to 11, the projection optics 14 can be made smaller, so that overall a more compact structure of the lighting device is produced (cf. the front view in FIG. 2).

(16) The converters 12 are of different sizes in the embodiment shown in FIGS. 1 to 6. In particular, the converters 12a at the upper edge of the matrix in the Y direction are larger than the converters 12 arranged further below (cf., for example, FIGS. 3 and 4). This is demonstrated particularly in FIG. 5 and FIG. 6, where a first converter 12a on an edge side in the Y direction is about three times as large in the Y direction than a second converter 12b arranged next to it. The Y direction in the light distribution corresponds to the vertical direction.

(17) FIGS. 5 and 6 illustrate that lateral boundaries 17 are provided between the individual light sources 11a, 11b and between the individual converters 12a, 12b. In this case, the outer light source 11a in the Y direction in FIG. 5 and FIG. 6 is substantially arranged at the left edge of the space formed by the two lateral boundaries 17, so that the light source 11a is arranged only under the left or first region 18 of the associated extended converter 12a, whereas no light source is provided under the right or second region 19 of the converter 12a.

(18) FIG. 5 illustrates that due to this arrangement of the light source 11a relative to the converter 12a, the first region 18 of the converter 12a is subjected to a greater luminous flux density of the light 13 emitted from the light source 11a than the second region 19 arranged further to the right in FIG. 5. In the middle diagram, FIG. 6 shows the corresponding luminous flux F as a function of the Y direction, which corresponds to the vertical direction in the light distribution. It can be seen that in the transition from the first to the second region 18, 19 of the converter 12a, the luminous flux 20 drops off gently.

(19) With the extended converter 12a and the selected arrangement of the light source 11a to the converter 12a, the desired soft vertical discharge of the light intensity can thus be made possible. A corresponding design with an extended converter 12a and a corresponding arrangement of the light source 11a to the converter 12a can be provided both above and below in FIGS. 3 and 4 or both in the near field and in the far field of the light distribution.

(20) The upper diagram of FIG. 6 shows the current I which flows through each light source 11a, 11b to be designed as a light emitting diode or a duty ratio of a pulse width modulation or the like, as a function of the Y direction. It was shown that the same current 21 can flow through all the light emitting diodes, so that the control of the light emitting diodes is simplified.

(21) FIG. 3 shows that all converters 12 are of equal size in the horizontal direction or in the X direction, wherein the individual converters 12 are separated from one another by corresponding lateral boundaries 17 in order to maintain the contrast in the horizontal direction.

(22) 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.