Lighting device for motor vehicle

Abstract

The invention relates to a lighting device for a motor vehicle, in particular a headlight for a motor vehicle, comprising at least one light source (1, 2, 3) and an optical system for generating a light distribution in the exterior of the motor vehicle, the optical system for generating the light distribution having an optical component (14) comprising a metamaterial, in particular, the metamaterial of the optical component (14) is designed to produce the light distribution.

Description

Technical Field

[0001] The invention relates to a lighting device for a motor vehicle, in particular a headlight for a motor vehicle, according to the preamble of claim 1 . Background Art

[0002] A lighting device of the type mentioned above is known from DE 10 2018 113 711 A1. The device described therein, which is designed as a headlight, has an illumination source and at least one measuring laser for a laser radar function, the measuring laser being a semiconductor laser and being designed to generate pulses with a pulse duration of at most 10 ns, wherein the wavelength of the maximum intensity of the measuring laser radiation generated by the measuring laser is between (inclusive of) 400 nm and 485 nm. The lighting device has an imaging optical system, which is common to all light sources and is used, for example, to generate a low beam. The imaging optical system is formed by a refractive and / or reflective optical system. The lighting device also has an imaging optical system, which is designed to image the measuring laser radiation generated by the measuring laser in a pattern and / or to scan with the measuring laser radiation. Here, the other imaging optical system is inseparably connected to the measuring laser, wherein the imaging optical system has a lens, a reflector, a diffractive optical element, a super lens, a multi-lens area and / or a diffuser.

[0003] It has proven to be disadvantageous here that the optical system for generating the light distribution of the headlight is designed to be refractive and / or reflective. The shape and size of the optical system are decisive for its optical function. Such systems are usually large and heavy. In addition, they offer few design freedoms. Summary of the invention

[0004] The problem underlying the invention is therefore to provide a lighting device of the type mentioned at the outset, the size and shape of which are not predetermined by a refractive or reflective optical system.

[0005] This is achieved according to the invention by a lighting device of the type mentioned at the outset having the characterizing features of claim 1. The dependent claims relate to preferred embodiments of the invention.

[0006] According to claim 1, it is provided that the optical system for generating the light distribution has an optical component including a metamaterial, in particular wherein the metamaterial of the optical component is designed to generate the light distribution. This makes it possible to shape the light emitted from the metamaterial without requiring a refractive or reflective optical system. Therefore, the external image of the lighting device and the size of the light exit surface of the lighting device are also not predetermined by the corresponding refractive or reflective optical system. In addition, the lighting device can be constructed in a simple and compact manner. Correspondingly, the lighting device can require less structural space and have a low weight. In addition, the lighting device can have a high efficiency, thereby achieving a high brightness.

[0007] It can be provided that the metamaterial of the optical component is designed to influence the light incident on the metamaterial like a phase hologram in order to generate the light distribution. Accordingly, the phase of the light interacting with the metamaterial is influenced by the metamaterial in such a way that a desired light distribution is generated in the exterior of the motor vehicle.

[0008] Instead of influencing the phase of the light, it is alternatively also possible to provide for influencing the amplitude of the light, in particular for amplitude modulation.

[0009] There is the possibility that the optical component has a particularly transparent carrier and a coating applied to the carrier, wherein the coating is structured in such a way that it forms the metamaterial. In this case, the coating can consist, for example, of TiO 2 Made of or having TiO 2 It is entirely possible to use other materials for the coating.

[0010] It can be provided that the coating has a plurality of structures spaced apart from one another on a surface, in particular on a surface facing away from the carrier, in particular wherein at least some of the structures have different sizes and / or different shapes from one another. In this case, the distances between the structures and / or the respective dimensions of the structures can be less than 1000 nm, in particular the distances between the structures and / or the respective dimensions of the structures can be between 50 nm and 900 nm. Such structures are also referred to as superatoms.

[0011] The structures spaced apart from one another can act here like small antennas, from which parts of the light interacting with the structures are respectively emitted or transmitted. In this case, the specific size and the specific shape of the individual structures are respectively responsible for a specific phase shift, which the light interacting with the metamaterial should experience at the location of the respective structure. The arrangement of the structures suitable for the desired intensity distribution as well as their shape and their size can be calculated using algorithms, which are known from the formation of computer-generated phase holograms. The structures can be formed in the coating, in particular, by lithographic methods, for example by electron beam lithography.

[0012] There is a possibility that the lighting device has a plurality of light sources, from which light is emitted during operation of the lighting device. Here, the plurality of light sources can be designed to respectively generate light having a wavelength spectrum that is different from the wavelength spectrum of light of other light sources, in particular the lighting device is designed to superimpose colored light emitted from the light sources in such a way that white light is generated. For example, it can be provided that the light sources are laser diodes, in particular wherein a first laser diode of the laser diodes is designed to generate red light, a second laser diode of the laser diodes is designed to generate green light, and a third laser diode of the laser diodes is designed to generate blue light. The three laser diodes thus together form an RGB light source. It is entirely possible to provide more than three laser diodes that are different from one another.

[0013] Alternatively, instead of the laser diode, a light-emitting diode (LED) with a corresponding color may also be provided.

[0014] There is the possibility that the metamaterial of the optical component is designed to influence the light incident on the metamaterial, such as a plurality of mutually different phase holograms, so that a colored partial light distribution is generated from the light of each of the light sources, the partial light distribution having the wavelength spectrum of the corresponding light source, in particular wherein the lighting device is designed to superimpose the colored partial light distributions in such a way that a white light distribution is generated. In this case, the plurality of light sources can be designed to respectively generate light with a polarization that is different from the polarization of the light of the other light sources, wherein the structure of the metamaterial, such as the effect of different phase holograms, influences the light emitted from the different light sources by polarization multiplexing technology in such a way that a colored partial light distribution is generated from the light of each of the light sources. These, in particular monochromatic partial light distributions, can then be superimposed in such a way that a white light distribution is generated. Polarization multiplexing technology prevents the occurrence of coloration effects or color fringes.

[0015] It can be provided that the light distribution is a low beam distribution and / or a high beam distribution and / or a daytime running light distribution. That is, for example, the structure of the metamaterial can be provided and shaped in such a way that each of the monochromatic partial radiations is influenced in such a way that it forms a corresponding monochromatic low beam distribution. These monochromatic partial low beam distributions can then be superimposed in such a way that they produce a white low beam distribution.

[0016] There is the possibility that the lighting device, in particular the headlight, has a plurality of light modules for generating different light functions, in particular wherein each of the light modules has at least one light source and an optical component comprising a metamaterial, the metamaterial being designed to generate a light distribution of the respective light function. In this case, for example, a first module of the modules can be used to generate a high-beam distribution and a second module of the modules can be used to generate a low-beam distribution.

[0017] It can be provided that the lighting device, in particular the headlight, has a light exit surface having a size of less than 10 mm×10 mm, in particular less than 5 mm×5 mm, preferably less than 2 mm×2 mm. The lighting device offers many degrees of freedom in design due to such a small light exit surface, in particular because it appears to the observer that the light comes “out of nothing” (no one knows where the light comes from).

[0018] Here, the light exit surface can have a polygonal cross section, such as in particular a rectangular or square cross section, or the light exit surface has a cross section with an at least partially curved boundary, such as in particular a circular cross section or an elliptical cross section. These possibilities for the shape of the cross section of the light exit surface also provide many degrees of freedom in construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The invention will now be further explained with reference to the accompanying drawings.

[0020] Figure 1 The structure of an embodiment of the lighting device according to the present invention is schematically shown. DETAILED DESCRIPTION

[0021] The lighting device shown is designed in particular as a headlight of a motor vehicle. The lighting device has three light sources 1, 2, 3, each of which is designed as a laser diode. Alternatively, the light sources can also be designed as light-emitting diodes.

[0022] The first light source 1 is a laser diode, which generates light 4 having a wavelength spectrum corresponding to red light. The light 4 of the first light source 1 is linearly polarized, wherein the polarization direction extends into Figure 1 in the plane of the graph (see Figure 1The second light source 2 is a laser diode, which generates light 5 having a wavelength spectrum corresponding to green light. The light 5 of the second light source 2 is also linearly polarized, wherein the polarization direction is horizontally in Figure 1 Extended in (see Figure 1 The third light source 3 is a laser diode, which generates light 6 having a wavelength spectrum corresponding to blue light. The light 6 of the third light source 3 is circularly polarized (see Figure 1 The corresponding arrow in 9).

[0023] The lighting device further comprises a first mirror 10, which is configured to reflect the light 4 emitted by the first light source 1 Figure 1 The lighting device also has a second mirror 11, which is designed as a dichroic mirror. The second mirror 11 makes Figure 1 The light 4 incident thereon from the left passes through unimpeded and the light 5 emitted from the second light source 2 is Figure 1 The lighting device also has a third mirror 12, which is also designed as a dichroic mirror. The third mirror 12 makes Figure 1 The light 4, 5 incident thereon from the left passes through unimpeded and the light 6 emitted from the third light source 3 is transmitted to the Figure 1 Thus, behind the third mirror 12, the light 4, 5, 6 emitted from the three light sources 1, 2, 3 are reflected to the right. Figure 1 Move to the right.

[0024] The lighting device further comprises Figure 1 A first quarter-wave plate 13, an optical member 14 including a metamaterial and a second quarter-wave plate 15 are arranged in the optical path of the light 4, 5, 6 propagating to the right in the image. The two quarter-wave plates 13, 15 are used to change the polarization state of the light 4, 5, 6 from line to circle (ring) and from circle to (straight) line.

[0025] The optical component 14 has a transparent carrier and a coating applied to the carrier, wherein the coating is structured in such a way that it forms a metamaterial. The coating can be composed, for example, of TiO 2 Made of or having TiO 2 It is entirely possible to use other materials for the coating.

[0026] The coating has a plurality of structures spaced apart from one another on the surface, in particular on the surface facing away from the carrier, wherein at least some of the structures have different sizes and / or different shapes from one another. The distances between the structures and / or the respective dimensions of the structures can be less than 1000 nm, in particular the distances between the structures and / or the respective dimensions of the structures can be between 50 nm and 900 nm. Such structures are also referred to as superatoms.

[0027] The structures spaced apart from one another can act like small antennas, from which a portion of the light 4, 5, 6 interacting with the structures is emitted or transmitted. In this case, the specific size and the specific shape of the individual structures are each responsible for a specific phase shift, which the light 4, 5, 6 interacting with the metamaterial experiences at the location of the respective structure.

[0028] Instead of influencing the phase of the light 4 , 5 , 6 , it is alternatively also possible to provide for influencing the amplitude of the light 4 , 5 , 6 , in particular for an amplitude modulation.

[0029] The arrangement of the structures suitable for the desired intensity distribution as well as their shape and their size can be calculated using algorithms known from the formation of computer-generated phase holograms. The structures can be formed in the coating in particular by lithographic methods, for example by electron beam lithography.

[0030] The structure affects the incident light 4, 5, 6 like a plurality of mutually different phase holograms, so that a colored partial light distribution is generated from the light 4, 5, 6 of each of the light sources 1, 2, 3, and the partial light distribution has the wavelength spectrum of the corresponding light source 1, 2, 3. Here, the structure of the metamaterial that acts like different phase holograms can appropriately influence the light 4, 5, 6 emitted from the different light sources 1, 2, 3 based on the different polarization states of the light 4, 5, 6 emitted from the light sources 1, 2, 3 by polarization multiplexing technology, so as to generate the desired colored partial light distribution.

[0031] For example, a structural arrangement can be provided for the light 4 , 5 , 6 of each of the light sources 1 , 2 , 3 , which influences the light 4 of the first light source 1 in such a way that a red partial low-beam distribution is generated, further influences the light 5 of the second light source 2 in such a way that a green partial low-beam distribution is generated, and influences the light 6 of the third light source 3 in such a way that a blue partial low-beam distribution is generated.

[0032] In this case, the lighting device is designed to superimpose the colored partial low-beam light distributions in such a way that a low-beam light distribution is generated in the exterior area of ​​the motor vehicle. Figure 11 and 2 , a schematically indicated white low-beam light distribution pattern 16 is shown. The low-beam light distribution pattern 16 has a schematically indicated horizontal light-dark boundary 17 in a known manner.

[0033] It is entirely possible to generate another light distribution, for example a high-beam distribution or a daytime running light distribution, instead of the depicted low-beam distribution 16 .

[0034] The light exit surface of the lighting device (not shown) may have a size that substantially corresponds to the size of the optical component 14 in a lateral direction arranged perpendicular to the propagation direction of the light 4, 5, 6. For example, the light exit surface may have a size of less than 10 mm×10 mm, in particular, a size of less than 5 mm×5 mm, preferably a size of less than 2 mm×2 mm. Reference numerals list

[0035] 1First Light Source

[0036] 2 Second light source

[0037] 3Third light source

[0038] 4 Light from the First Light Source

[0039] 5. Light from the Second Light Source

[0040] 6The light of the third light source

[0041] 7 Arrow of polarization direction of light of the first light source

[0042] 8 Arrow of polarization direction of light from the second light source

[0043] 9 Arrow of polarization direction of light of the third light source

[0044] 10 First Mirror

[0045] 11 Second Mirror

[0046] 12 The Third Mirror

[0047] 13The first quarter wave plate

[0048] 14Optical components including metamaterials

[0049] 15 Second quarter wave plate

[0050] 16 low beam distribution

[0051] 17 Horizontal light-dark boundary of low beam distribution

Claims

1. A lighting device for a motor vehicle, in particular a headlight for a motor vehicle, comprising at least one light source (1, 2, 3) and an optical system for generating a light distribution in the exterior area of ​​the motor vehicle, characterized in that The optical system for generating a light distribution has an optical component (14) comprising a metamaterial, in particular, the metamaterial of the optical component (14) is designed to generate the light distribution.

2. The lighting device according to claim 1, characterized in that The metamaterial of the optical component (14) is designed to influence light (4, 5, 6) incident on the metamaterial, such as in a phase hologram, in order to generate the light distribution.

3. The lighting device according to any one of claims 1 or 2, characterized in that: The optical component (14) has an in particular transparent carrier and a coating applied to the carrier, wherein the coating is structured such that it forms the metamaterial.

4. The lighting device according to claim 3, characterized in that The coating is made of TiO2 or comprises TiO2.

5. The lighting device according to any one of claims 3 or 4, characterized in that: The coating has a plurality of structures spaced apart from one another on a surface, in particular a surface facing away from the carrier, in particular at least some of the structures have different sizes and / or different shapes from one another.

6. The lighting device according to claim 5, characterized in that The distance between the structures and / or the respective dimensions of the structures is less than 1000 nm, in particular wherein the distance between the structures and / or the respective dimensions of the structures are between 50 nm and 900 nm.

7. The lighting device according to any one of claims 1 to 6, characterized in that: The lighting device comprises a plurality of light sources (1, 2, 3) from which light (4, 5, 6) is emitted during operation of the lighting device.

8. The lighting device according to claim 7, characterized in that The plurality of light sources (1, 2, 3) are designed to respectively generate light (4, 5, 6) having a wavelength spectrum that is different from the wavelength spectrum of light (4, 5, 6) of other light sources (1, 2, 3), and in particular, the lighting device is designed to superimpose colored light (4, 5, 6) emitted by the light sources (1, 2, 3) to generate white light.

9. The lighting device according to any one of claims 7 or 8, characterized in that: The light sources (1, 2, 3) are laser diodes, in particular, A first laser diode of the laser diodes is designed to generate red light (4), a second laser diode of the laser diodes is designed to generate green light (5), and a third laser diode of the laser diodes is designed to generate blue light (6).

10. The lighting device according to any one of claims 7 to 9, characterized in that The metamaterial of the optical component (14) is designed to influence light (4, 5, 6) incident on the metamaterial, such as in the form of a plurality of mutually different phase holograms, so that a colored partial light distribution is generated from the light (4, 5, 6) of each of the light sources (1, 2, 3), the partial light distribution having the wavelength spectrum of the corresponding light source (1, 2, 3), in particular, wherein the lighting device is designed to superimpose the colored partial light distributions so as to generate a white light distribution.

11. The lighting device according to claim 10, characterized in that The multiple light sources (1, 2, 3) are designed to respectively generate light (4, 5, 6) having a polarization, the polarization being different from the polarization of light (4, 5, 6) from other light sources (1, 2, 3), wherein the structure of the metamaterial, such as different phase holograms, influences the light (4, 5, 6) emitted from different light sources (1, 2, 3) through polarization multiplexing technology, so that the light (4, 5, 6) from each of the light sources (1, 2, 3) generates a colored partial light distribution.

12. The lighting device according to any one of claims 1 to 11, characterized in that The light distribution is a low beam light distribution (16) and / or a high beam light distribution and / or a daytime running light distribution.

13. The lighting device according to any one of claims 1 to 12, characterized in that: The lighting device, in particular the headlight, comprises a plurality of light modules for generating different light functions, in particular wherein each of the light modules comprises at least one light source (1, 2, 3) and an optical component (14) comprising a metamaterial, the metamaterial being designed to generate a light distribution of the corresponding light function.

14. The lighting device according to any one of claims 1 to 13, characterized in that The lighting device, in particular the headlight, has a light exit surface having dimensions of less than 10 mm×10 mm, in particular less than 5 mm×5 mm, preferably less than 2 mm×2 mm.

15. The lighting device according to claim 14, characterized in that The light exit surface has a polygonal cross section, such as in particular a rectangular or square cross section, or the light exit surface has a cross section with an at least partially curved boundary, such as in particular a circular cross section or an elliptical cross section.

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