Illumination device for a motor vehicle

Abstract

A lighting device for a motor vehicle, in particular a headlamp, comprising at least two, preferably three, light sources, from which light emanates during the operation of the lighting device, the light of each of the light sources differing from that of the other light sources with regard to its wavelength spectrum, comprising modulator, which bring about a modulation of the light emanating from the light sources during the operation of the lighting device, so that information is transmitted by the light, the lighting device having a mixer for mixing the light emanating from the individual light sources, so that white light emerges from the lighting device during the operation of the lighting device.

Claims

1. A lighting device for a motor vehicle, the lighting device comprising: at least two or at least three light sources from which light emanates during an operation of the lighting device, the light of the light sources differing from each other with regard to a wavelength spectrum; a modulator to bring about a modulation of the light emanating from the light sources during the operation of the lighting device so that information is transmitted by the light; a mixer to mix the light emanating from the individual light sources so that white light emerges from the lighting device during the operation of the lighting device, wherein the lighting device comprises an encoder, which encodes a piece of digital information to be transmitted during the operation of the lighting device, and wherein the encoder is implemented in a Manchester coding process during the operation of the lighting device, and wherein the modulator and the encoder are configured so that bit sequences of a piece of digital information to be transmitted are mapped sequentially to individual color points of an RGB space during the operation of the lighting device.

2. The lighting device according to claim 1, wherein the mixer for mixing the light emanating from the individual light sources comprises a fiber coupler, which combines the light of at least two light sources during the operation of the lighting device, at least two or three optical fibers being provided through each of which the light from the light sources reaches the fiber coupler.

3. The lighting device according to claim 2, wherein an outlet aperture of the fiber coupler or an outlet aperture of an output-side optical fiber connected to the fiber coupler is arranged within the lighting device.

4. The lighting device according to claim 1, wherein the light sources are lasers, semiconductor lasers, or light-emitting diodes (LEDs).

5. The lighting device according to claim 1, wherein, during the operation of the lighting device, a first light source emits red light, a second light source emits green light and a third light source emits blue light.

6. The lighting device according to claim 1, wherein the modulator carries out an on-off keying or a pulse-position modulation during the operation of the lighting device.

7. A lighting device for a motor vehicle, the lighting device comprising: at least two or at least three light sources from which light emanates during an operation of the lighting device, the light of the light sources differing from each other with regard to a wavelength spectrum; a modulator to bring about a modulation of the light emanating from the light sources during the operation of the lighting device so that information is transmitted by the light; a mixer to mix the light emanating from the individual light sources so that white light emerges from the lighting device during the operation of the lighting device, wherein the lighting device comprises an encoder, which encodes a piece of digital information to be transmitted during the operation of the lighting device, and wherein the encoder is implemented in a Manchester coding process during the operation of the lighting device, and wherein the modulator and the encoder are configured so that they generate voltage signals during the operation of the lighting device, which are used to supply voltage to the at least three light sources.

8. A receiver device for light of a lighting device according to claim 1, the receiver device comprising: a sensor that is adapted to separately detect the light emitted by the at least two or three light sources of the lighting device; and an evaluator that is adapted to extract the transmitted information from the detected light via demodulation and decoding.

9. The lighting device for a motor vehicle according to claim 1, wherein the lighting device is a headlamp.

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 shows a schematic view of a lighting device according to the invention; and

(3) FIG. 2 shows a schematic view of a receiver device according to the invention.

DETAILED DESCRIPTION

(4) The exemplary embodiment of a lighting device according to the invention illustrated in FIG. 1 may be designed, for example, as a headlamp, only parts of the headlamp being illustrated.

(5) The lighting device comprises three light sources 1, 2, 3, which have wavelength spectra which are different from each other. For example, light source 1 may emit red-colored light, light source 2 may emit green-colored light, and light source 3 may emit blue-colored light.

(6) Light sources 1, 2, 3 may be designed, in particular, as lasers, preferably as laser diodes. However, it is also possible that light sources 1, 2, 3 are designed as light-emitting diodes (LEDs).

(7) The lighting device furthermore comprises a modulator and an encoder, which are combined in a component 4. The modulator and the encoder may use a data signal 5, which is output, for example, from the on-board computer of a motor vehicle, for the purpose of modulating and encoding a voltage signal 6, 7, 8 used for controlling light sources 1, 2, 3. A separate voltage signal 6, 7, 8 is generated, modulated and encoded for each of light sources 1, 2, 3.

(8) In particular, each of voltage signals 6, 7, 8 is modulated differently than the other voltage signals 6, 7, 8. The modulation scheme and the encoding scheme are selected in such a way that the light emanating from light-emitting diodes 1, 2, 3 in its totality yields a white color impression. During the modulation of individual voltage signals 6, 7, 8, the frequency may be selected in such a way that the human eye perceives a constant intensity.

(9) It is possible to use an on-off keying as the modulation. A Manchester encoding may be used as the encoding. In addition, codes which detect errors or correct errors may be used.

(10) Alternatively, it is possible to map a first bit sequence of the data signal to a first color point in an RGB color space. This is done by selecting the amplitude of voltage signals 6, 7, 8 in such a way that light sources 1, 2, 3 emit corresponding light, which, in its totality, produces a color impression corresponding to this first color point in the RGB color space. Subsequent thereto, a second bit sequence is mapped to a second color point, which is different from the first one, after which a third bit sequence is mapped to a third color point, which is different from the first and second ones. A large number of consecutive bit sequences may be mapped to a large number of color points which differ from each other. On the whole, the color points may be selected in such a way that a white color impression results due to the different color points averaged over time.

(11) The mixer for mixing the light emanating from individual light sources 1, 2, 3, the lighting device comprises a fiber coupler 9 as well as three optical fibers 10, 11, 12, which connect light sources 1, 2, 3 to fiber coupler 9. The light emanating from the three light sources, 1, 2, 3 is mixed by fiber coupler 9 so that white light results. The lighting device furthermore comprises an output-side optical fiber 13 extending from fiber coupler 9, from whose outlet aperture 14 white light 15 emanates.

(12) The lighting device also comprises optics, which are disposed behind outlet aperture 14 and correspond, for example, to the typical functions of a headlamp. The light emanating from the lighting device may be used for lighting purposes as well as for communication between vehicles.

(13) The specific embodiment of a receiver device according to the invention illustrated in FIG. 2 comprises three photodiodes 16, 17, 18 used as the sensor, a color filter 19, 20, 21 being disposed in front of each one. The light is divided into the channels corresponding to the three colors by color filters 19, 20, 21. The light may be demodulated and decoded in this manner in evaluator 22 connected to photodiodes 16, 17, 18. The individual voltage signals may, if necessary, be amplified in the evaluator 22 prior to the demodulation and decoding. The demodulated and decoded signals may be combined into a data signal 23, which may be further processed.

(14) The receiver device may be disposed, for example, in a motor vehicle, which travels in front of the motor vehicle having the lighting device according to the invention.

(15) 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.