ILLUMINATION APPARATUS FOR A MOTOR VEHICLE

Abstract

The invention relates to an illumination apparatus (100), especially for a motor vehicle, comprising at least one laser light source (10); a wavelength conversion element (20) that is designed to receive excitation light from the at least one laser light source (10); and a reflector (30) having at least one reflector body (30′), which at least one reflector body (30′) comprises a reflecting surface (31), which reflecting surface (31) reflects the light emitted by the wave-length conversion element (20) in the visible wavelength range, wherein the reflector (30), at its reflector surface (30a) bearing the reflecting surface (31), is provided with the reflecting surface (31), wherein the reflector surface (30a) has at least one region (30a′, 30a″) that is free of the reflecting surface (31), and wherein the reflector surface (30a), at least in the region (30a′, 30a″) that is free of the reflecting surface (31), is embodied such that at least some of the excitation light incident in the region (30a′, 30a″) is absorbed.

Claims

1. An illumination apparatus (100), especially for a motor vehicle, comprising: at least one laser light source (10); a wavelength conversion element (20) that is designed to receive excitation light from the at least one laser light source (10); and a reflector (30) having at least one reflector body (30′), which at least one reflector body (30′) comprises a reflecting surface (31), which reflecting surface (31) reflects the light emitted by the wavelength conversion element (20) in the visible wavelength range, wherein the reflector (30), at its reflector surface (30a) bearing the reflecting surface (31), is provided with the reflecting surface (31), wherein the reflector surface (30a) has at least one region (30a′, 30a″) that is free of the reflecting surface (31), and wherein the reflector surface (30a), at least in the region (30a′, 30a″) that is free of the reflecting surface (31), is embodied such that at least some of the excitation light incident in the region (30a′, 30a″) is absorbed.

2. The illumination apparatus of claim 1, wherein the reflector surface (30a) is coated with a reflecting material that forms the reflecting surface (31).

3. The illumination apparatus of claim 2, wherein in the at least one region (30a′) that is free of the reflecting surface (31) the reflector surface (30a) is not coated with the reflecting material or, after coating, the reflecting material is removed in the at least one region (30a′) so that at least some incident excitation light is absorbed on the reflector surface.

4. The illumination apparatus of claim 1, wherein the reflector body (30′) has at least one through-hole (32), and wherein the at least one through-hole (32) is closed with a closure element (33), wherein the surface (33′) of the closure element (33), which surface is disposed on the side of the reflecting surface (31), forms the region (30a″) that absorbs at least some of the excitation light.

5. The illumination apparatus of claim 4, wherein the surface (33′) of the closure element (33) closes the entire through-hole (32).

6. The illumination apparatus of claim 4, wherein the closure element (33) is embodied and/or is inserted into the through-hole (32) such that the surface (33′) transitions essentially continuously to the reflecting surface (31).

7. The illumination apparatus of claim 1, wherein the at least one excitation light-absorbing region (30a′, 30a″) is embodied such that most or all of the excitation light is absorbed.

8. The illumination apparatus of claim 1, wherein the at least one absorbing region (30a′, 30a″) is embodied resistant to temperature.

9. The illumination apparatus of claim 1, wherein the at least one absorbing region (30a′, 30a″) is embodied non-temperature resistant above a limit temperature.

10. The illumination apparatus of claim 9, wherein the limit temperature is 120° C.

11. The illumination apparatus of claim 1, wherein an excitation light-absorbing region (30a′, 30a″) is arranged in or on the reflector surface (30a) such that excitation light from the laser light (10) source directly incident on the reflector surface and/or excitation light that is emitted by the conversion element (20) is incident on the absorbing region (30a, 30a″).

12. The illumination apparatus of claim 11, wherein an absorbing region (30a′, 30a″) is arranged, and is embodied with respect to its surface extension, such that all of the excitation light directly from the laser light source (10) and incident on the reflector surface and/or all of the excitation light that is emitted by the conversion element (20) is incident on the absorbing region (30a′, 30a″).

13. The illumination apparatus of claim 12, wherein an absorbing region (30a′, 30a″) is arranged, and is embodied with respect to its surface extension, such that all of the excitation light incident on the reflector surface directly from the laser light source (10) and/or all of the excitation light that is emitted by the conversion element (20) is incident exactly and only on the absorbing region (30a′, 30a″).

14. A motor vehicle headlight having at least one illumination apparatus according to claim 1.

15. A motor vehicle having at least one illumination apparatus according to claim 1.

Description

[0050] The invention shall be explained in greater detail in the following using the drawings.

[0051] FIG. 1 is a schematic depiction of a first embodiment of an inventive illumination apparatus;

[0052] FIG. 2 is a schematic depiction of a second embodiment of an inventive illumination apparatus;

[0053] FIG. 3 depicts an enlarged excerpt from FIG. 1 in the area of the absorbing region;

[0054] FIG. 4 depicts an enlarged excerpt from FIG. 2 in the area of the absorbing region formed by a closure element; and,

[0055] FIG. 4a depicts the excerpt from FIG. 4 prior to the closure element being inserted into the reflector.

[0056] FIG. 1 depicts an illumination apparatus 100 comprising a laser light source 10, a conversion element 10, and a reflector 30. The laser light source 10 emits excitation light 200 (“primary light”) that is incident on the conversion element 20, is converted by the latter to e.g. white mixed light 202 in the manner described in the foregoing, is emitted by the conversion element 20 onto the reflector 30, and is emitted by the latter into the exterior for forming a light distribution.

[0057] The light distribution that may be produced with the illumination apparatus is for instance a low beam distribution; a high beam distribution; part of a low beam or high beam distribution; cornering, adaptive, freeway, fog, inclement weather, or blinker light distribution, etc.; or one or more parts of the foregoing.

[0058] FIG. 2 also depicts an illumination apparatus 100; the statements made in the foregoing apply to it in the same way, as well.

[0059] The difference between the illumination apparatus 100 in FIGS. 1 and 2 is found in the type of conversion element 20 and the arrangement resulting therefrom.

[0060] The illumination apparatus 100 according to FIG. 1 has a transmissive conversion element 20 that radiates mixed light 202 at least on its side/surface facing away from the laser light source 10. In principle light may be radiated in all directions by the conversion element, and, e.g., optical apparatus that are upstream of the conversion element and that act like a filter may be employed to be able to use the converted light that is reflected back in this manner, but the further optical system is disposed on the side/surface facing away from the laser light source.

[0061] Excitation light 200 that is incident on the conversion element 20 is primarily incident on the reflector 30 in the beam cone 201, especially if there is a fault as described above. Therefore an excitation light-absorbing region 30a′ is provided on the reflector 30 in a region of the reflector on which the excitation light cone 201 is incident (more precisely, the sectional surface between the reflector surface and the cone 201) so that excitation light 201 that is incident on the reflector is absorbed.

[0062] The illumination apparatus 100 according to FIG. 2 has a reflective conversion element 20 that emits mixed light 202 on its side/surface facing the laser light source 10. Excitation light 200 that is incident on the conversion element 20 is primarily reflected onto the reflector 30 in the beam cone 201, especially if there is a fault as described above. Therefore an excitation light-absorbing region 30a″ is provided on the reflector 30 in a region of the reflector on which the excitation light cone 201 is incident (more precisely, the sectional surface between the reflector surface and the cone 201) so that excitation light 201 that is incident on the reflector is absorbed.

[0063] FIG. 2 provides only a schematic depiction of the conversion element. Frequently the latter is arranged on a support or comprises a support that is preferably embodied as reflecting so that the mixed light is emitted with a higher yield. If there is a fault, e.g. if the conversion element drops from the support, however, the safety risk increases substantially due to reflection of the laser beam on the reflecting support. This risk may be reduced significantly with the inventive embodiment as described above.

[0064] Different embodiments of an absorbing region 30a′, 30a″ on the specific reflector 30 are discussed in the following using the two illumination apparatus 100 from FIG. 1 and FIG. 2. It should be noted that the embodiment of the absorbing region of the illumination apparatus 100 from FIG. 1 could be implemented in exactly the same manner for the illumination apparatus from FIG. 2 instead of the absorbing region 30a″ illustrated there, and, likewise, the absorbing region 30a″ described in detail in the following according to the illumination in FIG. 2 may also be embodied or implemented in the reflector from FIG. 1 instead of the absorbing region 30a′ illustrated there. Furthermore, it is also possible for an illumination apparatus as depicted in the two figures to have two or more absorbing regions for excitation light. The absorbing regions may be embodied identically, but differently realized absorbing regions, as depicted in the following, may also be implemented together in one illumination apparatus.

[0065] FIG. 3 illustrates a detail from FIG. 1. A segment of the reflector 30 is depicted, wherein this reflector 30 comprises a reflector body 30′, and wherein this reflector body 30′ comprises or has a reflecting surface 31 that reflects the light or mixed light that was produced by the wavelength conversion element 20 and is in the visible wavelength range. As already explained using FIG. 1, this reflected light later produces a light distribution in the exterior upstream of the illumination apparatus.

[0066] The reflecting surface 31 is applied to one side of the reflector 30, specifically the so-called reflector surface 30a of the reflector body 30′. For instance, the reflector surface 30a may be coated with the reflecting surface 31, as shall be explained in greater detail in the following. The reflecting surface 31 is formed from a light-reflecting material in order to be able to reflect light that is in the visible wavelength range as just described in the foregoing.

[0067] According to the invention, the reflector surface 30a has a region that is free of the reflecting surface 31. This free region represents an excitation light-absorbing region 30a′ that absorbs at least some, preferably most, or even, advantageously, all of the excitation light incident there-on. The excitation light-absorbing region 30a′ that is free of the reflecting surface 31 may be produced such that, when the reflector surface 30a is treated, e.g. coated, the latter is not provided the reflecting material, e.g. is not coated, in the desired region, for instance the region may be masked or otherwise covered prior to the reflecting material being applied so that no material that forms the reflecting surface 31 reaches this region. However, it is also possible for the entire reflector surface 30a to be provided with the reflecting material first, for instance to be coated, and then for the reflecting surface 31 to be removed again in the desired region that is to be absorbing, at least for the excitation light.

[0068] The absorbing region 30a′ is thus formed from the “base material” forming the reflector body 30′, which base material comprises a light-absorbing material, especially the material that absorbs the excitation light. This base material is formed from e.g. PEI (polyetherimide) or PC (polycarbonate) or contains one of these materials, which have a high temperature resistance.

[0069] FIG. 4 and FIG. 4a provide a detail view of a reflector 30 from FIG. 2. In the embodiment illustrated, the reflector 30 again has a reflector body 30′, wherein the reflector body 30′ is provided with a reflecting surface 31. In the embodiment illustrated, the reflector 30 as shown in FIG. 1 thus again comprises the reflector body 30′, which has a reflector surface 30a to which the reflecting surface 31 is applied, for instance by coating. But in this embodiment it may also be provided that, for instance, the entire reflector 30 is already formed from a reflecting material, that is, that reflector body 30′ and reflecting surface 31 are embodied in one piece. In this case there is no terminological distinction between reflector surface and reflecting surface.

[0070] Regardless of the specific manner in which the reflector 30 is embodied (see previous paragraph), in the embodiment illustrated according to 2 and FIGS. 4, 4a it is provided that the reflector 30 or reflector body 30′ has a through-hole 32, wherein this through-hole 32 may be closed with a closure element 33. The surface 33′ of the closure element 33, which when the closure element 33 is inserted is disposed on the side of the reflecting surface 31, forms at least some of the excitation light-absorbing region 30a″, preferably most of it or all of it. As is depicted in FIG. 4, it is preferable for the closure element 33 to be embodied such that, when inserted, the surface 33′ of the closure element 33 completely closes the through-hole 32. In particular it is advantageous when the surface 33′ of the closure element 33 essentially connects in a continuous manner to the reflecting surface 31.

[0071] The closure element 33 is preferably made of an absorbing material (such as was already mentioned, e.g. polycarbonate, PBT, or ABS). Using the closure element 33, the through-hole 32 is preferably covered from the back or external side of the reflector body 30′ or preferably closed as described above by inserting the closure element 33, adapted appropriately to the through-hole 32, into the through-hole 32 as described in the foregoing.

[0072] The closure element 33 may be made of an absorbing material that is resistant to increased temperature due to the emitted laser light (excitation light), so that the laser light is absorbed and does not leave the illumination apparatus. But it is also possible to use absorbing material that is not resistant to increased temperature due to the laser light. In this case, the laser light is first absorbed at an absorbing region 30a″ until a certain limit temperature is reached (e.g. 120° C.) and the closure element 33 melts or burns. Laser light then travels through the open through-hole 32 and is lost in the rear portion of the illumination apparatus.

[0073] The absorbing region may also be produced by means of a multi-component injection molding method. The absorbing region may be a) produced from an absorbing material that is resistant to the increase in temperature due to the laser light or b) embodied from an absorbing material that is not, however, resistant to the temperature increase but has the qualities described in the foregoing.

[0074] An injection molding processes is best suited for producing a reflector in connection with the present invention. In principle it is also possible to use a pressure casting method, especially in combination with an injection molding method, (e.g. a reflector body with an opening could be produced in the pressure casting method and the closure element could be produced with the injection molding method).

[0075] An embodiment according to FIG. 4 prevents laser light from being able to exit from the headlight, or reduces the risk thereof, in the event of a fault.

[0076] In an injection molding process, during the production of a reflector body with an opening a so-called “joint line” is created due to the method; in some cases it may be unwanted for esthetic reasons. In addition, there may disadvantageously be scatter light in the region of the limit of the opening.

[0077] The problem of the joint line is also solved with the variant according to FIG. 3 (removing or not applying the reflecting coating). Since no opening has to be produced in the reflector body, no joint line can be created, either. As a rule the coating is very thin, typically in the neighborhood of 140 nm, so that the transition or step between coated region and uncoated region is irrelevant in terms of light; therefore no disadvantageous scatter light can occur there, either.

[0078] With sufficiently precise production, such disadvantageous scatter light does not occur in an embodiment according to FIG. 4 in the region between the opening and closure element, either.