Lighting device for vehicle

Abstract

The invention relates to a lighting device for a vehicle, comprising a light source (16) and a flat light guide (5), which comprises opposite flat sides (6, 7) and a narrow side (8) connecting the flat sides, the front flat side (6) being for the light emission of light emitted from the light source (16) and coupled into the flat light guide (5), and the narrow side (8) being for the light emission of light emitted from the light source (16) and coupled into the flat light guide (5). The flat light guide (5) has a front flat side (6), a micro-optical element is associated with the front flat side (6), the flat light guide (5) is flexible, and the flat light guide (5) is surrounded by retaining elements at least on opposite narrow sides (14) such that the flat light guide (5) has a fixed curvature in the mounted position.

Description

Field of the Invention

[0001] The present invention relates to a lighting device for a vehicle, the lighting device having a light source and a flat light guide, the flat light guide comprising opposite flat sides and a narrow side connecting the flat sides, wherein the front flat side is for light emission of light emitted from the light source and coupled into the flat light guide, and a micro-optical element is provided for the front flat side. Background Art

[0002] A lighting device for a vehicle is known from DE102019133693A1, the lighting device comprising a flat light guide having opposite flat sides and a narrow side connecting the flat sides. A light source is arranged on the narrow side of the flat light guide such that light is coupled into the flat light guide through the narrow side of the flat light guide. In order to enable the coupled-in light to be emitted on the front flat side of the flat light guide, an optical sheet having a plurality of micro-optical elements is provided, wherein the optical sheet abuts against the front flat side of the flat light guide with the flat side provided with the micro-optical elements. Advantageously, uniform illumination can thus be achieved on the front flat side of the flat light guide. Since the optical sheet and the flat light guide are manufactured by injection molding, the manufacturing cost is relatively high when the flat light guide has to have different curvatures in order to follow the line shape of the headlamp or the lamp (Strakverlauf). In particular, when it is necessary to maintain an equal distance between the flat light guide and the closing sheet of the housing covering the lighting device, different tools are required to manufacture the corresponding number of flat light guides with different degrees of curvature. Summary of the Invention

[0003] Therefore, the object of the present invention is to improve a lighting device for a vehicle such that planar and uniform illumination is ensured, wherein different surface curvatures or surface archings

[0004] can be provided in a simple manner. To solve the above object, the present invention is characterized in combination with the preamble of claim 1 in that the flat light guide is configured to be flexible, and the flat light guide is surrounded by holding elements at least on the opposite narrow sides such that the flat light guide has a fixed curvature in the assembled position.

[0005] A particular advantage of the present invention is that the surface curvature of the flat light guide in the assembled position does not depend on its manufacture, but on the following frame or sub-frame, to which the flat light guide is fixed via holding elements. In order to assemble, for example, a plurality of flat light guides with different surface curvatures following the course of a closing sheet, the same flat light guides can be used. Only the holding elements of the frame or sub-frame or the frame / sub-frame are different. If the flat light guide to be assembled should have a greater surface curvature than other flat light guides already assembled, then the flat light guide is fixed, for example, to the following holding elements opposite one another on the frame, the net spacing of which is chosen to be smaller, so that the surface curvature is greater. Thus, the frame has the strength to predetermine the surface curvature. Thereby, the manufacturing effort can be significantly reduced.

[0006] According to a preferred embodiment of the invention, the at least two holding elements are integrally formed on the frame or on the sub-frame, which is made of a rigid material or at least partially made of a rigid material. The frame completely surrounds the flat light guide in the case of abutting on the narrow sides, while the sub-frame only partially surrounds the flat light guide. If the frame is made of a rigid material, then the surface arching of the flat light guide is determined by the spacing between the holding elements. Alternatively, if the frame is only partially made of a rigid material, for example comprises a flexible frame section and a rigid fixing section connected thereto, then the flexible frame section surrounds the flat light guide. The flexible frame section is configured such that it has a greater strength than the flat light guide, so that the flat light guide has a fixed curvature permanently in the assembled position. The rigid fixing section serves to hold the frame on the housing of the lighting device. Thus, a frame consisting of two parts can be manufactured, for example, by two-component injection molding. Via the rigid fixing section, the frame can be fixed, for example, to the holding part on the housing by means of threaded parts or by means of snap-lock parts.

[0007] According to an improvement of the invention, the flat light guide is made of a transparent silicone resin material. The flat light guide can be manufactured, for example, by injection molding, wherein only a single tool is required.

[0008] According to a preferred embodiment of the invention, a plurality of light sources are distributed on the rear flat side of the flat light guide. Preferably, these light sources are arranged evenly distributed, so as to ensure uniform illumination of the flat light guide. Preferably, the flat light guide has micro-optical elements on the rear flat side in the regions that are not filled with light sources for reflecting and coupling the light input into the flat light guide. Preferably, the flat light guide has micro-optical elements on the front flat side in the regions of the axial extensions to the light sources for scattering the light emitted on the front flat side. The micro-optical elements on the front flat side can be arranged, for example, in a circular region, the center point of which is passed through by the optical axes of the light sources. Advantageously, by this measure, a simple homogenization of the surface illumination is ensured.

[0009] According to an improved embodiment of the present invention, an optical sheet is arranged on the front flat side of the flat light guide, and the optical sheet has micro-optical elements arranged on the side facing away from the flat light guide for scattering the coupled-out light. The optical sheet is also configured to be flexible and is preferably made of the same material as the flat light guide. Advantageously, the adjustment of the light output characteristics can be adapted to different requirements by means of an additional optical sheet.

[0010] According to an improved embodiment of the present invention, instead of the optical sheet, an optical film can be arranged on the front flat side. In this way, the flat light guide module thus formed can be made even thinner.

[0011] According to an improved embodiment of the present invention, a covering member having a diffuse reflection surface is connected to the rear flat side of the flat light guide, so that on the one hand, a uniform background in the non-operating state of the lighting device is ensured, and on the other hand, the scattered light emitted on the rear flat side in the operating state can be reflected back into the flat light guide.

[0012] Other advantages of the present invention are given by the other dependent claims. Description of the Drawings

[0013] Embodiments of the present invention will be described in more detail below with reference to the drawings.

[0014] In the drawings:

[0015] Figure 1 A schematic top view of a taillight is shown, which has a plurality of flat light guide modules extending equidistantly from a closing piece.

[0016] Figure 2 A front view of a flat light guide module is shown.

[0017] Figure 3 An exploded view of the flat light guide module is shown from the front.

[0018] Figure 4 An exploded view of the flat light guide module is shown from the back.

[0019] Figure 5 A vertical cross-section of a flat light guide according to a first embodiment is shown.

[0020] Figure 6 A vertical cross-section of a flat light guide according to a second embodiment is shown.

[0021] Figure 7 A front view of a flat light guide is shown, which has a light source plotted on the back side and a scattering area on the front flat side.

[0022] Figure 8 A front view of a flat light guide module according to another embodiment is shown. Detailed implementation mode

[0023] The lighting device can be configured, for example, as a taillight or a headlight in a vehicle. In Figure 1 the housing 1 is shown, the opening of which is usually covered by a transparent closing piece 2. Inside the housing 1, a plurality of flat light guide modules 3, 3', 3", 3'" extend at an equal distance from the closing piece 2. These flat light guide modules differ in that they have different vertical and / or horizontal lengths and / or different surface curvatures. The first flat light guide module 3, the second flat light guide module 3', the third flat light guide module 3" and the fourth flat light guide module 3'" extend from the side wall of the vehicle in the direction 4 of the vehicle central axis. The second flat light guide module 3' has a greater surface curvature than the first flat light guide module. The radius of curvature r 2 of the second flat light guide module 3' is smaller than the radius of curvature r 1 of the first flat light guide module 3. The radius of curvature r 1 , r 2 preferably extends in the horizontal direction, so that the curvature of the flat light guide modules 3, 3', 3", 3'" only extends in the horizontal direction, as especially shown by Figure 3 and Figure 4 visible. The third flat light guide module 3" has a radius of curvature r 1 , r 2 greater than the radius of curvature r 3 of the first flat light guide module 3 and the second flat light guide module 3'. The fourth flat light guide module 3'" extends flatly and has a smaller horizontal extension dimension than the other flat light guide modules 3, 3', 3".

[0024] The flat light guide modules 3, 3', 3", 3'" are each composed of the same components. Hereinafter, only the first flat light guide module 3 will be described by way of example. The flat light guide module 3 has a flat light guide 5, which has opposite flat sides, namely a front flat side 6 and a rear flat side 7, and the front flat side is used as a light-emitting surface. The front flat side 6 and the rear flat side 7 are connected to each other by a narrow side 8. An optical sheet 9 having a plurality of optical elements 10 is connected to the front flat side 6 of the flat light guide 5. The optical sheet 9 is adhesively attached to the front flat side 6 of the flat light guide 5 in a planar manner. The flat light guide 5 and the optical sheet 9 are each configured to be flexible and are preferably made of a flexible and highly transparent silicone resin material.

[0025] The flat light guide 5 and the optical sheet 9 are fixed to the frame 11 via a holding device (not shown). The frame 11 has a flexible frame section 12, which surrounds the flat light guide 5 and the optical sheet 9 on the narrow sides of the flat light guide and the optical sheet. In addition, the frame 11 has a rigid fixing section 13, which extends substantially transversely to the axis of the flexible frame section 12 and serves as a projection for holding the flat light guide module 3 on the housing 1.

[0026] The frame 11 can be manufactured, for example, by two-component injection molding. The flexibility or flexibility of the flexible frame section 12 is preferably less than the flexibility or flexibility of the flat light guide 5 or the optical sheet 9. The surface curvature of the flat light guide 5 or the optical sheet 9 in its assembled state is predetermined by the width b of the flexible frame section 12 and / or by a holding device (not shown) on the upright frame part 14 of the flexible frame section 12. If the width b between the frame parts 14 or the holding device (not shown) on the frame part 14 is less than a predetermined value, then the surface curvature of the flat light guide 5 or the optical sheet 9 increases, where the radius of curvature r 1 decreases. In this way, the surface curvature of the flat light guide 5 or the optical sheet 9 can be adjusted within a predetermined curvature range by the frame 11. In the simplest case, different surface curvatures can be adjusted by different holding elements. This must involve not only the vertical frame part 14, but also the horizontal frame part 15, so that the surface curvature can also be adjusted about the vertical axis.

[0027] As can be seen from Figure 5 As can be seen, a plurality of LED light sources 16 are distributed on the rear flat side 7 of the flat light guide 5. These LED light sources are respectively located in the recesses of the rear flat side 7, so that the LED light sources 16 end flush with the rear flat side 7. The LED light sources 16 are interconnected via thin wire conductor circuits (not shown) and are connected to the plug-in joint contacts on the back side.

[0028] On the rear flat side 7 of the flat light guide 5, a back-side covering 17 is connected, which has a diffusely reflecting, preferably white surface. The back-side covering 17 can be connected to the frame 11 integrally, for example, or connected to the frame 11 and / or the flat light guide 5 via fixing devices. The back-side covering 17 forms the background surface of the flat light guide module 3 and, in the operating state of the flat light guide module 3, causes the scattered light emitted from the rear flat side 7 of the flat light guide 5 to be reflected back into the flat light guide 5.

[0029] As can be seen from Figure 5 As can be seen, the rear flat side 7 of the flat light guide 5 has reflecting elements 19 in the region 18 without the LED light source 1. By means of these reflecting elements, the undesired emission of scattered light on the rear flat side 7 is prevented and thus the surface illumination of the flat light guide 5 is made uniform. The reflecting elements 19 can be manufactured by structuring or embossing.

[0030] The optical sheet 9 has optical elements 10 in the region 20 on the front flat side facing away from the flat light guide 5, which are used to scatter and / or reflect the light incident from the flat light guide 5 into the optical sheet 9. As can be seen from Figure 7As can be seen, the optical element 10 extends in the circular region 20 in the present embodiment, and the circular region is arranged coaxially with the corresponding LED light source 16. The circular region 20 is coaxial with the optical axis A of the assigned light source 16. In this way, light concentration or bright spots in the extension of the LED light source 16 on the flat light guide module 3 can be prevented.

[0031] The optical sheet 9 can have a thickness in the range between 1 mm and 2 mm. The optical element 10 is configured as a micro-optical element.

[0032] Alternatively, the optical sheet 9 can be replaced by an optical film having a thickness in the range of 0.1 mm to 0.5 mm. The optical film also has an optical element 10 with a micro-structured part or a more diffused structured part.

[0033] According to another alternative embodiment of the present invention Figure 6 the flat light guide module 3 has neither an optical sheet nor an optical film. Alternatively, the optical elements 10 are arranged on the front flat side 6 of the flat light guide 5. These optical elements 10 can be implemented (as in the optical sheet 9) by embossing or structuring.

[0034] As can be inferred from Figure 6 the beam L1 directly emitted by the light source 1 or the beam L2 totally reflected on the flat sides 6, 7 is scattered by means of the optical element 10. The beam L3 incident on the rear flat side 7 at a relatively steep angle is reflected by means of the reflection element 19 and then generally exits as the beam L2 on the front flat side 6. Alternatively, the reflected beam L3' can also be reflected by means of the optical element 10, so that it exits from the flat light guide on the front side by further total reflection and moves along the extension direction of the flat light guide 5.

[0035] In a simple embodiment (not shown) of the flat light guide module 3, there can also be provided only one flat light guide 5 not equipped with an optical element 10.

[0036] Alternatively, the flat light guide 5 can either have a reflection element 19 on the rear flat side 7 or an optical element 10 on the front flat side 6.

[0037] The configuration of the flat light guide module 3 having the reflection element 19 and / or the optical element 10 depends on the desired degree of homogenization of the surface illumination.

[0038] According to another embodiment (not shown) of the present invention, a plurality of optical sheets may also be arranged in front of the flat light guide 5. The optical sheets have optical elements for shaping and focusing light such that the light radiation proceeds more convergently. The optical elements may, for example, be prismatic or in the form of strips or in the form of pyramids or other micro-optical elements or microstructures. The optical element 21 may, for example, be configured as a white dot grid or as a printed grid having lines, triangles, rectangles, polygons or other geometric shapes.

[0039] Alternatively, if the thickness of the optical element layer is calibrated with respect to the desired residual transmittance, the region 20 may also be entirely imprinted with optical elements.

[0040] According to the present invention Figure 8 Another embodiment of the flat light guide module 23 is provided as follows. The flat light guide module is different from the flat light guide modules 3, 3', 3'', 3''' in that the frame 22 is made of a rigid material. Preferably, the frame 20 is configured as a rigid plastic injection molding, wherein the shape of the frame 22 corresponds to the shape of the frame section 12 of the flat light guide modules 3, 3', 3'', 3'''. The frame 22 is fixedly connected to the housing 1 via a holding device (not shown).

[0041] The holding device may, for example, be a latching device or a threaded connection or an adhesive.

[0042] According to an alternative embodiment (not shown) of the present invention, the flat light guide may also be surrounded by a sub-frame, wherein not all of the narrow sides 8 of the flat light guide are surrounded by the sub-frame. The sub-frame may, for example, be configured as U-shaped, thereby ensuring that the opposite narrow sides of the flat light guide can be fixed to the opposite holding elements of the sub-frame and the surface curvature is adjustable.

[0043] List of reference numerals

[0044] 1 Housing

[0045] 2 Closing sheet

[0046] 3, 3', 3'', 3''' Flat light guide module

[0047] 4 Direction

[0048] 5 Flat light guide

[0049] 6 Front flat side

[0050] 7 Rear flat side

[0051] 8 Narrow side

[0052] 9 Optical sheet

[0053] 10 Optical element

[0054] 11 Frame

[0055] 12 Flexible frame section

[0056] 13 Rigid fixing section

[0057] 14 Frame part

[0058] 15 Frame part

[0059] 16 LED light source

[0060] 17 Cover

[0061] 18 Area

[0062] 19 Reflective element

[0063] 20 Area

[0064] 22 Frame

[0065] 23 Flat light guide module

[0066] b Width

[0067] r 1 、r 2 、r 3 Radius of curvature

[0068] L1, L2, L3, L3’ Light beams

Claims

1. Lighting device for a vehicle, the lighting device having a light source (16) and a flat light guide (5), the flat light guide comprising opposite flat sides (6, 7) and a narrow side (8) connecting the flat sides, a front flat side (6) for emitting light that is emitted from the light source (16) and coupled into the flat light guide (5), and a micro-optical element is provided for the front flat side (6). It is characterized in that the flat light guide (5) is constructed to be flexible, and the flat light guide (5) is surrounded by holding elements at least on opposite narrow sides (14) such that the flat light guide (5) has a fixed curvature in the assembled position.

2. The lighting device according to claim 1, It is characterized in that the holding elements are integrally formed on a frame (22) or a sub-frame, and the frame (22) or the sub-frame is made of a rigid material.

3. The lighting device according to claim 1, It is characterized in that the holding elements are arranged on the frame (11), the frame on the one hand having a flexible frame section (12) that surrounds the flat light guide (5), and the frame on the other hand having a rigid fixing section (13) that is integrally connected to the frame section as a protrusion transverse to the frame section (12) for holding the frame (11) on the housing (1) of the lighting device.

4. The lighting device according to any one of claims 1 to 3, It is characterized in that the flat light guide (5) is made of a transparent silicone material.

5. The lighting device according to any one of claims 1 to 4, It is characterized in that a plurality of light sources (16) are arranged in recesses in the rear flat side (7) of the flat light guide (5), preferably ending flush with the rear flat side (7).

6. The lighting device according to any one of claims 1 to 5, It is characterized in that the flat light guide (5) has a reflective element (19) on the rear flat side (7) in a region (18) for reflecting the coupled-in light in the direction towards the front flat side (6), and light is not coupled into the region from the rear flat side (7).

7. The lighting device according to claim 6, It is characterized in that the reflective element (19) is constructed as an embossed element or a structural element.

8. The lighting device according to any one of claims 1 to 7, It is characterized in that an optical sheet (9) abuts on the front flat side (6) of the flat light guide (5), or the front flat side (6) is provided with an optical film, and the optical sheet (9) or the optical film has the micro-optical element (10).

9. The lighting device according to claim 8, It is characterized in that the micro-optical element (10) of the optical sheet (9) is manufactured by embossing or by structuring.

10. The lighting device according to claim 8 or 9, It is characterized in that the optical sheet (9) has a thickness in the range of 1 mm to 2 mm.

11. The lighting device according to any one of claims 8 to 10, It is characterized in that the optical film has a thickness in the range of 0.1 mm to 0.5 mm.

12. The lighting device according to any one of claims 1 to 11, It is characterized in that the optical element (10) is arranged in a region (20) on the front flat side (6) of the flat light guide (5) or on the front side of the optical sheet (9) facing away from the flat light guide (5), the region extending in the axial extension of the optical axis (A) to the light source (16) and having an area greater than the area of the light source (16).

13. The lighting device according to any one of claims 1 to 12, It is characterized in that a backside covering (17) is provided for the back flat side (7) of the flat light guide (5), the covering being formed by a diffusely reflecting surface.

14. The lighting device according to any one of claims 1 to 13, It is characterized in that a further optical sheet is arranged on the front side of the optical sheet (9) or the optical film and / or the flat light guide (5), the further optical sheet comprising optical elements for shaping and focusing the coupled-out light.

15. The lighting device according to any one of claims 1 to 14, It is characterized in that the holding devices of the frame (11, 22) or the sub-frame are arranged on opposite sides of the frame or the sub-frame for determining the spacing (b) of the opposite narrow sides (14) of the flat light guide (5) and / or the optical sheet (9), such that the flat light guide (5) or the optical sheet (9) has a predefined curvature about an axis extending between the holding elements in the assembled position.

16. The lighting device according to any one of claims 1 to 15, It is characterized in that the holding elements are configured as latching devices, threaded devices or adhesives.

17. The lighting device according to any one of claims 1 to 16, It is characterized in that the flat light guide (5) and the frame (11, 22) and / or the optical sheet (9) and / or the backside covering (17) form a flat light guide module (3, 3', 3", 3"'), and a plurality of the flat light guide modules are arranged side by side and / or one on top of the other at an equal distance from the closing sheet (2) closing the housing (1) within the housing (1).

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