Lighting device for the interior of a motor vehicle

Abstract

The invention relates to a lighting device for the interior of a motor vehicle, the lighting device comprising a light source (2) and a light guide (3) which comprises a transparent light guiding portion (301). The lighting device (1) is designed such that light originating from the light source (2) enters the light guiding portion (301) via a light entry surface (3a) and at least some of the light is guided, via the light guiding portion (301), to a light exit surface (3b) through which the light from the lighting device (1) exits in order to be emitted into the interior. In the lighting device (1), a translucent scattering element (4) is adjacent to the light entry surface (3a) of the light guiding portion (301). The scattering element (4) is designed such that it scatters the light originating from the light source (2) before it enters the light guiding portion (301).

Description

[0001] LIGHTING DEVICE FOR THE INTERIOR OF A MOTOR VEHICLE

[0002] The invention relates to a lighting device for the interior of a motor vehicle.

[0003] It is known from the prior art to use light guides for illuminating the interior of a motor vehicle. For example, German patent application DE 10 2013 016 346 A1 discloses a vehicle interior component for generating ambient lighting, in which the light from a light source is deflected via light-reflecting surfaces and enters the interior of the motor vehicle via the light-emitting surface of a light guide.

[0004] Lighting devices for vehicle interiors are also known from the prior art, in which a diffusing element or lens is provided on a light guide, the lens scattering the light emitted via the light guide, thus producing diffuse light emission. The use of such lenses has the disadvantage that the light output from the lighting device has a milky appearance, which is not very aesthetically pleasing.

[0005] The object of the invention is to create a lighting device for the interior of a motor vehicle that is structurally and / or functionally improved and at the same time has an appealing appearance.

[0006] This problem is solved by the lighting device according to claim 1. Further developments of the invention are defined in the dependent claims.

[0007] The lighting device according to the invention is intended for the interior of a motor vehicle, i.e., it is a lighting device for the passenger compartment of the motor vehicle. The motor vehicle is preferably a passenger car, but may also be a truck. Where interactions between the lighting device and components of the motor vehicle or its interior are described below, and in particular in the claims, this is always to be understood as meaning that the interaction occurs when the lighting device is arranged or installed in the motor vehicle. The components of the lighting device that have a corresponding interaction with the motor vehicle or its components are therefore designed such that the interaction is caused by the arrangement or installation of the lighting device in the motor vehicle or its interior.

[0008] The lighting device according to the invention comprises a light source and a light guide, which includes a transparent light guide section. Here and in the following, the term "transparent" is to be understood as clear or non-scattering, whereby a corresponding transparent component or a transparent light guide section may also be colored, provided it transmits light without scattering. The lighting device is designed such that light originating from the light source enters the light guide section via a light entry surface and is guided at least partially via the light guide section to a light exit surface, wherein the light exit surface is preferably smooth and thus unstructured. The light exits the lighting device via the light exit surface for emission into the interior of the motor vehicle. The light entry surface and the light exit surface are integral parts of the light guide section.

[0009] The lighting device according to the invention is characterized in that a light-transmitting scattering element is arranged adjacent to the light entry surface of the light guide section and preferably adjacent to the light entry surface of the light guide section, wherein the scattering element is designed in such a way that it scatters (i.e. diffusely deflects) the light originating from the light source before it enters the light guide section.

[0010] The lighting device according to the invention has the advantage that a corresponding diffusing element is not provided directly at the light output of the lighting device, but instead a transparent light guide section is used there, which directs the light from the diffusing element. In this way, a diffuse light distribution is still generated, but the light output surface of the lighting device appears clear without the undesirable milky appearance of a diffusing element. In addition, a depth effect is created when viewing the light guide section or its light output surface.

[0011] In a preferred embodiment of the lighting device according to the invention, a further transparent light guide section of the optical fiber is arranged between the diffuser element and the light source. The light from the light source is at least partially coupled into the further light guide section via a light coupling surface and is then at least partially directed to a light coupling surface, through which the light enters the diffuser element. The light coupling surface and the light coupling surface are integral parts of the further light guide section. This embodiment of the invention achieves efficient coupling of the light from the light source into the optical fiber with low losses.

[0012] In another preferred embodiment, the light-entry surface of the light-guiding section is structured and, for example, faceted. This allows for attractive lighting effects, such as a crystalline appearance.

[0013] In another preferred embodiment, an outer surface of the light guide section, located between the light-intake surface and the light-outtake surface, is at least partially mirrored towards the light guide section. This means that light rays traveling within the light guide section towards a region of the mirrored outer surface are reflected by the mirrored surface. Optionally, the entire outer surface extending around the light guide section between the light-intake and light-outtake surfaces can be mirrored. This mirroring allows for aesthetically pleasing mirror effects at the light output of the lighting device.

[0014] In a further preferred embodiment, the light guide section and the diffuser element are integrally formed as a single component, preferably as an injection-molded part. This variant ensures simple manufacturing of the lighting device according to the invention. Optionally, the further light guide section described above, which is provided in one variant of the invention, can also be part of the single component. Furthermore, optionally, at least a part of the housing described below can be part of the single component.

[0015] In a further preferred embodiment, the light guide section and / or the further light guide section (if present) is made of plastic, in particular PMMA (PMMA = polymethyl methacrylate) or PC (PC = polycarbonate). Alternatively or additionally, in a further variant, the scattering element is made of plastic, such as PMMA or PC, wherein light-scattering particles, which may consist of titanium oxide, for example, are embedded in the plastic.

[0016] In a further preferred embodiment, the light guide section is elongated along a longitudinal direction when viewed from above the light-emitting surface. In another embodiment, the light source comprises one or more light sources, which are preferably LEDs. If the light guide section is elongated along a longitudinal direction, the light source preferably contains several light sources arranged side by side and preferably at regular intervals (i.e., with equal spacing) along this longitudinal direction. The regular arrangement of the light sources results in more homogeneous brightness along the light-emitting surface.

[0017] In a further preferred embodiment, the light source, the light guide, and the diffuser are arranged in a housing that includes a light-emitting opening where the light-emitting surface of the light guide section is located. This ensures easy installation of the lighting device in the vehicle. Furthermore, the housing protects the components of the lighting device and prevents unwanted stray light, as light emission is ensured exclusively via the light-emitting surface of the light guide section. Preferably, the housing includes a flange for mounting the lighting device in the vehicle's interior.

[0018] In a further preferred embodiment, the lighting device according to the invention is designed such that, when installed in the motor vehicle, the light emission surface of the light guide section is arranged adjacent to an interior trim surface, wherein the light emission surface is preferably oriented such that the light emitted via the light emission surface falls at least partially onto the interior trim surface.

[0019] In a preferred embodiment of the above, the lighting device is provided for installation in a vehicle door, wherein the interior trim surface is a door panel surface. Nevertheless, the lighting device according to the invention can also be provided for installation in other locations in the interior of the vehicle, such as in the headliner, the dashboard, or the backrests of passenger seats.

[0020] In a specific variant of the embodiment described above, the door panel surface extends vertically upwards from an armrest surface of the vehicle door, and the light-emitting surface of the lighting device is positioned between the door panel surface and the armrest surface to emit light towards the door panel surface. This achieves a very attractive diffuse illumination of the vehicle door.

[0021] In addition to the lighting device described above, the invention relates to a motor vehicle comprising one or more of the lighting devices according to the invention or one or more preferred variants of the lighting device according to the invention.

[0022] Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawings.

[0023] They show:

[0024] Fig. 1 shows a perspective view of an embodiment of a lighting device according to the invention; and

[0025] Fig. 2 shows a section along the section line L through the lighting device of Fig. 1.

[0026] The lighting device 1 shown in Fig. 1 is designed for installation in a vehicle door of a motor vehicle (not shown) and serves to illuminate a surface of a door panel (hereinafter also referred to as a door mirror and not visible in the figures) that is directed towards the interior of the vehicle and is located above an armrest.

[0027] The lighting device 1 comprises a housing 5 with an upper housing section 501 and a lower housing section 502, both of which are opaque and, for example, clipped together. A light source 2, which is shown in Fig. 2 and described in more detail below, is located in the housing 5. Furthermore, a light guide 3 with a first light guide section 301 and a second light guide section 302 is arranged in the housing 5. Both light guide sections 301 and 302 are transparent (i.e., clear and transmitting light). The first light guide section 301 is a light guide section as defined in the claims, and the second light guide section 302 is another light guide section as defined in the claims. The second light guide section 302, of which only its upper end is visible in Fig. 1, is shown in detail in Fig. 2.Between the first light guide section 301 and the second light guide section 302 there is a diffusing element 4. This diffusing element is translucent, but has a milky appearance because it causes light scattering of the transmitted light.

[0028] The upper housing section 501 comprises two upwardly projecting side walls 5a, between which the first light guide section 301, the diffuser 4, and part of the second light guide section 302 are arranged. The side walls 5a form a light exit opening 6, on which a top surface of the first light guide section 301 is located. This top surface constitutes a light exit surface 3b of the first light guide section 301. The light exit opening 6 is further bounded by a front wall and a rear wall, each extending between the two side walls 5a. The front and rear walls have been omitted in Fig. 1 to reveal the structure of the first and second light guide sections 301, 302, and the diffuser 4. The upper housing section 501 also includes a horizontally extending web 5b, to which a vertically extending flange 5c is attached.For reinforcement, ribs 5e are located between web 5b and flange 5c. For clarity, the ribs in Fig. 1 are only partially labelled with the reference numeral 5e.

[0029] The flange 5c has openings 5d through which the housing 5, and thus the lighting device 1, is screwed to the door mirror from the rear when installed in the vehicle. The lower end of the door mirror is located between the ribs 5e and the rear of the left side panel 5a. Protruding screw bosses are provided on the rear of the door mirror, which align with the corresponding openings 5d. These screw bosses are screwed into the openings 5d with screws.

[0030] When the lighting device 1 is installed, an armrest (not shown) of the vehicle door is located next to the right side wall 5a. Thus, the light emission opening 6, or rather the light emission surface 3b, is located between the interior-facing surface of the door mirror and the armrest. To illuminate the door mirror, the lighting device 1 contains a light source 2 in the lower housing section 502, which is visible in Fig. 2. The light source 2 contains a plurality of light sources 201, which, during operation, emit light into the second light guide section 302. From there, the light passes into the diffuser element 4, which causes the light to be diffused. The diffused light then travels via the first light guide section 301 to the light emission surface 3b, from which it illuminates the surface of the door mirror above it.

[0031] A key feature of the lighting device in Fig. 1 is that the diffuser element 4 is not located directly at the light emission aperture 6, but is offset downwards relative to the light emission surface 6. Instead, the transparent first light guide section 301, with its light emission surface 3b, is arranged at the light emission aperture 6. This ensures that the light-emitting surface of the lighting device 1 appears clear, like glass optics, so that no undesirable frosted glass effect occurs at the light emission aperture 6. This results in a very aesthetically pleasing appearance both when the lighting device 1 is switched on and when it is switched off. Fig. 2 shows a sectional view along the section line L of Fig. 1.For emphasis, the upper housing section 501 is shown hatched and the lower housing section 502 is shown dotted, while the other components are shown in white. Fig. 2 shows in particular the light source 2, which comprises a circuit board 202 on which the plurality of light sources 201 in the form of LEDs are located. The LEDs are arranged side by side in the longitudinal direction of the light guide 3 (i.e., in the direction perpendicular to the plane of Fig. 2), so that light is emitted from the lighting device 1 along the entire length of the light-emitting surface 3b. The distance between adjacent LEDs is typically about 20 to 30 mm. For example, sixteen LEDs can be provided side by side in the lighting device 1.

[0032] Figure 2 further illustrates the structure of the second light guide section 302. This light guide section extends straight downwards towards the light sources 201, such that a lower light coupling surface 3c of the second light guide section 302 is positioned adjacent to the light sources 201. A large portion of the light from the light sources 201 couples into the second light guide section 302 via the light coupling surface 3c. A portion of the coupled light is guided via the second light guide section 302 to the light coupling surface 3d, which is located between the side walls 5a of the upper housing section 501. The shape of the second light guide section 302 shown in Figure 2 is merely exemplary. The second light guide section 302 can also have a different shape, the shape preferably being optimized with regard to the efficiency of the optical light guide system.

[0033] The scattering element 4 adjoins the light output surface 3d, so that the light enters the scattering element 4 via the light output surface. There, the light is scattered (i.e., deflected in an undirected manner). The light then enters the first light guide section 301 via the light input surface 3a, which adjoins the top of the scattering element 4. The light is then guided between the outer surfaces 3e of the first light guide section 301, which are adjacent to the side walls 5a, to its light output surface 3b, from which it shines upwards towards the surface of the door mirror. The light output surface 3b is slightly inclined, which directs the emerging light rays towards the surface of the door mirror, because the inclination of the light output surface 3b causes the light rays to be refracted away from the normal of the light output surface 3b.This is because the refractive index of the first light guide section 301 is greater than the refractive index of the surrounding air. In the embodiment shown in Fig. 2, the light guide 3, i.e., the light guide sections 301 and 302, as well as the diffusing element 4 and the upper housing section 501, are integrally formed as a single component. The single component is manufactured by injection molding. The components of the single component are therefore made of plastic. Preferably, the light guide 3 (i.e., the light guide sections 301 and 302) is made of PMMA or PC. The diffusing element 4 is preferably made of PMMA or PC containing light-scattering particles, for example, titanium oxide. Preferably, the upper housing section 501 and, analogously, the lower housing section 502 are made of PC-ABS (= polycarbonate / acrylonitrile butadiene styrene copolymer).

[0034] In a preferred embodiment, the light-entry surface 3a of the first light-guiding section 301 is structured, creating a structured interface between the first light-guiding section 301 and the diffusing element 4. Attractive lighting effects can be generated via this structured interface when viewing the light-emission surface 3b. For example, the structuring of the interface can be faceted, resulting in a crystalline appearance. In a further preferred embodiment, the outer surfaces 3e of the first light-guiding section 301 are mirrored towards the interior of the first light-guiding section. The reflections caused by this mirroring also lead to a very appealing appearance.

[0035] The lighting device described with reference to Figures 1 and 2 is designed for installation in the vehicle door of a motor vehicle. However, other embodiments of the lighting device according to the invention may also be intended for installation in other locations within the vehicle interior, such as in the dashboard or the headliner.

[0036] The embodiments of the invention described above offer a number of advantages. In particular, a lighting device with an aesthetically pleasing appearance is created in both the switched-on and switched-off states. This is achieved by no longer positioning a corresponding diffusing element directly at the light output aperture of the lighting device, but rather offsetting it from the light output aperture. Instead, a transparent light guide section is located at the light output aperture, which transmits the diffused light from the diffusing element. Consequently, the milky appearance of the diffusing element is not visible from outside the lighting device, and the aesthetically pleasing appearance of a glass optic is created at the light output. [List of reference numerals]

[0037] 1 lighting device

[0038] 2 light bulbs

[0039] 201 light sources (LEDs)

[0040] 202 circuit board

[0041] 3 optical fibers

[0042] 301 Light cable section (first light cable section)

[0043] 302 further light cable section (second light cable section)

[0044] 3a Light entry surface of the light guide section

[0045] 3b Light emission surface of the light guide section

[0046] 3c Light coupling area of ​​the further light guide section

[0047] 3D light output surface of the further light guide section

[0048] 3e Outer surface of the light guide section

[0049] 4 scattering element

[0050] 5 cases

[0051] 501 upper case section

[0052] 502 lower housing section

[0053] 5a projecting side walls of the upper housing section

[0054] 5b Bridge of the upper housing section

[0055] 5c Flange of the upper housing section

[0056] 5d openings in the flange

[0057] 5e ribs of the upper housing section

[0058] 6 light exit aperture

Claims

Claims 1. Lighting device for the interior of a motor vehicle, comprising a light source (2) and a light guide (3) which includes a transparent light guide section (301), wherein the lighting device (1) is designed such that light originating from the light source (2) enters the light guide section (301) via a light entry surface (3a) and is guided at least partially via the light guide section (301) to a light exit surface (3b), through which the light exits the lighting device (1) for emission into the interior, characterized in that a light-transmitting diffusing element (4) is arranged adjacent to the light entry surface (3a) of the light guide section (301), wherein the diffusing element (4) is designed such that it diffuses the light originating from the light source (2) before entering the light guide section (301).

2. Lighting device according to claim 1, characterized in that a transparent further light guide section (302) of the light guide (3) is arranged between the diffusing element (4) and the light source (2), wherein the light of the light source (2) is coupled at least partially into the further light guide section (302) via a light coupling surface (3c) and is guided at least partially via the further light guide section (302) to a light output surface (3d), through which the light enters the diffusing element (4).

3. Lighting device according to claim 1 or 2, characterized in that the light entry surface (3a) of the light guide section (301) is structured.

4. Lighting device according to one of the preceding claims, characterized in that an outer surface (3e) of the light guide section (301), which is located between the light entry surface (3a) and the light exit surface (3b), is mirrored at least section by section towards the light guide section (301).

5. Lighting device according to one of the preceding claims, characterized in that the light guide section (301) and the diffusing element (4) are integrally formed as a one-piece component, preferably as an injection-molded component.

6. Lighting device according to one of the preceding claims, characterized in that the light guide section (301) is made of plastic, in particular of PMMA (PMMA = polymethyl methacrylate) or of PC (PC = polycarbonate).

7. Lighting device according to one of the preceding claims, characterized in that the scattering element (4) is made of plastic, in particular of PMMA (PMMA = polymethyl methacrylate) or of PC (PC = polycarbonate), wherein light-scattering particles, in particular of titanium oxide, are embedded in the plastic.

8. Lighting device according to one of the preceding claims, characterized in that the light guide section (301) is designed elongated along a longitudinal direction in a top view of the light emission surface (3b).

9. Lighting device according to one of the preceding claims, characterized in that the light source (2) comprises one or more light sources (201) and preferably one or more LEDs.

10. Lighting device according to one of the preceding claims, characterized in that the light source (2), the light guide (3) and the diffusing element (4) are arranged in a housing (5) which includes a light emission opening (6) on which the light emission surface (3b) of the light guide section (301) is located.

11. Lighting device according to claim 10, characterized in that the housing comprises a flange (5c) for fastening the lighting device (1) in the interior of the motor vehicle.

12. Lighting device according to one of the preceding claims, characterized in that the lighting device (1) is designed such that, when installed in the motor vehicle, the light emission surface (3b) of the light guide section (301) is arranged adjacent to an interior trim surface, wherein the light emission surface (3b) is preferably oriented such that the light emitted via the light emission surface (3b) falls at least partially onto the interior trim surface.

13. Lighting device according to claim 12, characterized in that the lighting device (1) is provided for installation in a vehicle door of the motor vehicle and the interior trim surface is a door trim surface.

14. Lighting device according to claim 13, characterized in that the door panel surface extends vertically upwards from an armrest surface of the vehicle door and the light emission surface (3b) of the lighting device (1) is arranged between the door panel surface and the armrest to emit light towards the door panel surface.

15. Motor vehicle comprising one or more lighting devices according to any of the preceding claims

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