Lighting device for vehicles

Abstract

The invention relates to a lighting device for vehicles with a light source (2) and with a light guide (1), which has a first light guide section (7) comprising a light coupling surface (8) for coupling in light (5) emitted by the light source (2), a second light guide section (9) comprising a light coupling surface (10) for coupling out the coupled light (5), wherein the light coupling surface (10) has an optical structure (15), a reflection section (11) arranged between the first light guide section (7) and the second light guide section (9) comprising a reflection surface (12) at which the coupled light (5) is deflected in the direction of the second light guide section (9), wherein the light coupling surface (10) of the light guide (1) has an edge region (16, 16', 16") which does not have an optical structure (15), such that the reflection surface (12) of the reflection section (11) in such a region (19, 19',19") optical scattering elements (20) at which a portion of the coupled light (5) is deflected in the direction of the second optical fiber section (9) and is coupled out in the edge region (16) of the light output coupling surface (10) of the second optical fiber section (9).

Description

[0001] The invention relates to a lighting device for vehicles with a light source and with a light guide, which has a first light guide section containing a light coupling surface for coupling in a light emitted by the light source, a second light guide section containing a light coupling surface for coupling out the coupled light, wherein the light coupling surface has an optical structure, a reflection section arranged between the first light guide section and the second light guide section containing a reflection surface at which the coupled light is deflected in the direction of the second light guide section.

[0002] DE 10 2013 100 557 A1 discloses a lighting device for vehicles comprising a light source and a light guide. The light guide comprises a first light guide section with a light coupling surface, a second light guide section with a light output surface, and a reflection section arranged between these two sections. The reflection section serves to deflect the coupled-in light and has an optical structure. The light output surface has cushion optical elements as an optical structure. The cushion optical elements extend over the entire surface of the light output surface.

[0003] Furthermore, AT 518 552 A4 discloses a lighting device comprising a light source and a light guide. The light guide comprises a first light guide section with a light coupling surface, a second light guide section with a light coupling surface, and a reflection section arranged between the first light guide section and the light guide section. The reflection section serves to deflect the coupled-in light toward the light coupling surface. The light coupling surface has corrugations or prism elements as an optical structure that extend over the entire surface of the light coupling surface.

[0004] When manufacturing known lighting devices by injection molding, the problem arises that if a tool contacts an edge region of the light-output surface, the optical structure can be damaged. To prevent this damage, it is known to not provide an optical structure at the edge of the light-output surface where the tool contacts. However, this results in the problem that, particularly at a steep viewing angle on the light-output surface, undesirable optical effects such as an LED hotspot, glitter effects, or an inhomogeneous appearance are created due to the smooth surface of the edge region of the light-output surface.

[0005] The object of the present invention is to further develop a lighting device for vehicles in such a way that undesired optical effects are avoided in a simple manner if an edge region of a light coupling surface is designed to be free of optics.

[0006] To achieve this object, the invention in conjunction with the preamble of claim 1 is characterized in that the light output surface of the light guide has an edge region which has no optical structure, that the reflection surface of the reflection section has optical scattering elements in such a region at which a portion of the coupled-in light is deflected in the direction of the second light guide section and is coupled out in the edge region of the light output surface of the second light guide section.

[0007] The particular advantage of the invention is that unwanted light effects are easily avoided by providing an optics-free edge region of a light-output surface. The basic idea of ​​the invention is to arrange optical scattering elements at such an area or location of the reflection surface, which would otherwise reflect the coupled-in light in the untreated state with a smooth surface, so that it exits at the edge region of the light-output surface. This prevents light concentrations or the occurrence of, for example, LED hotspots (light source hotspots). Thus, scattered light reaches the edge region of the light-output surface.

[0008] According to a preferred embodiment of the invention, such a region of the reflection surface is provided with optical scattering elements which, if smooth, would lead to a reflection of the coupled-in light directly to the edge region of the light output surface. Thus, by means of the region of the reflection surface provided with scattering elements, the coupled-in light is scattered onto the light which would otherwise strike the edge region of the light output surface unscattered. In the case of a light guide, this particularly involves light components that are guided in a straight line and parallel to a light guide direction in the first light guide section and the second light guide section. In particular, these are light components that are not totally reflected, but experience the only total reflection in the reflection section at a reflection surface.

[0009] According to a preferred embodiment of the invention, the reflection surface projected perpendicularly onto the light-output surface overlaps or corresponds to the light-output surface in terms of its dimensions. If the dimension of the reflection surface corresponds to the light-output surface, an edge region of the reflection surface is free of optical scattering elements. If the projected reflection surface is larger than the light-output surface, the optically free edge region of the reflection surface can also be located at a distance from an edge of the reflection surface.

[0010] According to a further development of the invention, the width of the optics-free area of ​​the reflection surface is greater than the width of the edge area of ​​the light-output surface. This ensures that an undesirable light effect is avoided across the entire edge area of ​​the light-output surface.

[0011] Further advantages of the invention emerge from the further subclaims. An embodiment of the invention is explained in more detail below with reference to the drawings.

[0012] They show: Fig. 1 a cross section through a lighting device according to the invention, Fig. 2 a cross-section through a known lighting device and Fig. 3 a partial front view of a light output surface of a Fig. 2 shown known light guide.

[0013] A lighting device according to the invention can be used to generate a signal light function, for example, daytime running lights or the like. The lighting device essentially comprises a light guide 1 and a number of light sources 2.

[0014] In the present embodiment, the light guide 1 is designed as a flat light guide having opposing flat sides 3 and narrow sides 4 connecting the same. A coupled light 5 is totally reflected at the flat sides 3.

[0015] The light sources 2 are arranged in rows on a carrier plate 6 (circuit board). The light sources 2 are designed as LED light sources.

[0016] The light guide 1 has a first light guide section 7 which has a light coupling surface 8 on a side facing the light sources 2, in which the light 5 emitted by the light sources 2 is coupled into the light guide 1.

[0017] Furthermore, the light guide 1 has a second light guide section 9, which has a light output surface 10 for coupling out the coupled light 5.

[0018] Between the first light guide section 7 and the second light guide section 9, a reflection section 11 of the light guide 1 is arranged, which has a reflection surface 12 at which the light 5 emerging from the first light guide section 7 is deflected in the direction of the second light guide section 9.

[0019] The flat sides 3 and the narrow sides 4 extend from the light coupling surface 8 of the light guide 1 to the light coupling surface 10 thereof, with the flat sides 3 not running parallel to each other only in the reflection section 11. Instead, an inner flat side 3 of the first light guide section 7 merges directly into an inner flat side 3' of the second light guide section 9, while the outer flat side 3" of the first light guide section 7 is connected to the outer flat side 3" of the second light guide section 9 via the reflection surface 12.

[0020] The reflection surface 12 of the reflection section 11 forms an angle of 45° with the outer flat sides 3" of the first light guide section 7 and the second light guide section 9. The light output surface 10 runs at a right angle to a light exit surface 13 of the first light guide section 7 or runs parallel to a light entry surface 14 of the second light guide section 9. In the present embodiment, the reflection surface 12 is flat. Alternatively, the reflection surface 12 can also be curved.

[0021] In the present embodiment, the dimension of the reflection surface 12 projected perpendicularly onto the light output surface 10 corresponds to the dimension of the light output surface 10.

[0022] According to an alternative embodiment of the invention not shown, the dimension of the reflection surface 12 in vertical projection onto the light output surface 10 can also be smaller or larger than the dimension of the light output surface 10.

[0023] In the present embodiment, the light guide 1 has an L-shaped cross-section. Both the light coupling surface 8 and the light coupling surface 10 are rectangular.

[0024] The light coupling surface 8 can be designed such that the coupled light 5 is parallelized. Alternatively, a collimator (not shown) can be provided between the light sources 2 and the light coupling surface 8, by means of which the light 5 is parallelized. It then enters the preferably flat light coupling surface 8 perpendicularly. Alternatively, light coupling means in the region of the light coupling surface 8 can also be designed such that only a portion of the coupled light 5 is parallelized. Another portion of the coupled light does not run parallel to a light guide direction 22 and can thus be totally reflected at the opposite flat sides 3' or 3".

[0025] In any case, the coupled-in light 5 can comprise at least light components that are guided in a straight line and parallel to the light guide direction 22 in the optical fiber 1, wherein the light guide direction 22 runs substantially perpendicular to the light coupling surface 8 and / or the light output surface 10. In particular, these are then light components that are not totally reflected, but rather experience the only total reflection at the reflection surface 12 of the reflection section 11.

[0026] The light output surface 10 has an optical structure 15 for scattering the light 5 output therefrom. Since the light guide 1 is manufactured by injection molding, a tool must engage or contact the light guide 1 in an edge region 16 of the light output surface 10, which leads to mechanical stress on this edge region 16. As a result, the optical structure 15 in this edge region 16 would be damaged, which would undesirably impair the required light image. Therefore, in practice, the edge region 16 of the light output surface 10 is left open, i.e., it has no optical structure 15.

[0027] As can be seen from the Fig. 2 and Fig. 3, this leads to undesirable light concentrations on the light output surface 10 at a certain viewing angle, in particular from LED hotspots 17, which extend along a long side of the light output surface 10. To prevent the occurrence of these LED hotspots 17 or these light concentrations or these inhomogeneities of the light image, the invention provides for optical scattering elements 20 to be provided in an edge region 19 of the reflection surface 12.

[0028] In projection of the reflection surface 12 perpendicular to the light output surface 10, these optical scattering elements 20 cover the edge region 16 of the light output surface 10, so that the coupled-in light 5 impinging on the edge region 16 of the light output surface 10 is scattered and output.

[0029] In the present exemplary embodiment, the coupled-in light 5 is deflected by 90° by means of the reflection surface 12. The reflection surface 12 is provided with optical scattering elements 20 in the edge region 19, wherein the edge region 19 of the reflection surface 12 covers the edge region 16 of the light output surface 10 perpendicular to the latter. If the light guide 1 did not have an angular profile, the optical scattering elements 20 of the reflection surface 12 would not have to be located in an edge region. It is essential that the reflection surface 12 has the optical scattering elements 20 in such a region that reflects such a portion of the coupled-in light 5 that, after entering the second light guide section 9 or further light guide sections, strikes the edge region 16 of the light output surface 8.

[0030] It is assumed that the reflection surface 12 has the optical scattering elements 12 exclusively in the edge region 19. In the remaining region of the reflection surface 12, it has no optical scattering elements 20. The remaining region is formed as a main region 21 of the reflection surface 12, which serves for the unscattered reflection of the coupled-in light 5. The main region 21 of the reflection surface 12 is thus smooth. The reflection of the coupled-in light 5 occurs by total internal reflection on a flat surface formed by the main region 21. Alternatively, the main region 21 can also be mirrored.

[0031] In the present exemplary embodiment, the optics-free edge region 16 of the light-outcoupling surface 10 extends only along opposite long sides 18 of the light-outcoupling surface 10, which simultaneously form a peripheral edge of the outer flat side 3" and inner flat side 3' of the second light guide section 9. Thus, two opposing edge strips 16 form the edge region 16 on the light-outcoupling surface 10. There are no optics-free regions on the narrow sides 18' of the light-outcoupling surface 10. Instead, the optical structure 15 extends continuously from a first narrow side 18' to the opposite narrow side 18' of the light-outcoupling surface 10.

[0032] Accordingly, the edge regions 19 of the reflection surface 12 are formed as edge strips, wherein only one edge strip 19' adjoining the light exit surface 13 of the first light guide section 7 and one edge strip 19" adjoining the light entry surface 14 of the second light guide section 9 are formed, which run parallel to each other. The edge strips 19', 19" of the reflection surface 12 run parallel to the edge strips 16', 16" of the light output surface 10. An edge width b R the edge strip 19', 19" is chosen larger than an edge width b A the edge strips 16', 16" of the light output surface 10 or so much larger than the same that it is ensured that only light reflected at the edge strips 19', 19" or in the edge region 19 strikes the edge strips 16, 16' of the light output surface 10.

[0033] The light guide 1 according to the invention thus differs from that in Fig. 2 in that it has optical scattering elements 20 on the reflection surface 12 in the edge region 19, with the main region 21 of the reflection surface 12 being smooth. The known light guide 1' has a completely flat and smooth reflection surface 12.

[0034] The optical scattering elements 20 can be manufactured by etching, lasering, or sandblasting. For example, the optical scattering elements 20 can be formed as an eroded structure. For example, the optical scattering elements 20 can be formed as optical micro-scattering elements. The optical scattering elements 20 can also be formed by diffractive optics. For example, the optical scattering elements 20 can be formed as a roughening produced by sandblasting.

[0035] According to an alternative embodiment of the invention (not shown), the light guide 1 can also have multiple reflection sections 11 or more than two light guide sections. The shape of the light guide 1 depends on the installation space in the vehicle. List of reference symbols 1 light guide 2 light sources 3.3',3" flat sides 4 narrow sides 5 light 6 Carrier plate 7 1. Fiber optic section 8 Light coupling surface 9 2nd fiber optic section 10 Light output surface 11 Reflection section 12 Reflection surface 13 Light exit surface 14 Light entry surface 15 optical structure 16,16',16" edge areas 17 LED hotspots 18.18' long sides 19,19',19" edge area 20 optical scattering elements 21 Main area 22 bR ,b A Border width QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2013 100 557 A1

[0002] AT 518 552 A4

[0003]

Claims

[1] Lighting device for vehicles with a light source (2) and with a light guide (1) which has - a first light guide section (7) containing a light coupling surface (8) for coupling in a light (5) emitted by the light source (2), - a second optical fiber section (9) containing a light output surface (10) for coupling out the coupled-in light (5), wherein the light output surface (10) has an optical structure (15), - a reflection section (11) arranged between the first optical fiber section (7) and the second optical fiber section (9) containing a reflection surface (12) at which the coupled-in light (5) is deflected in the direction of the second optical fiber section (9), characterized by , - that the light output surface (10) of the light guide (1) has an edge region (16, 16', 16") which has no optical structure (15), - that the reflection surface (12) of the reflection section (11) has optical scattering elements (20) in such a region (19, 19', 19"), in which a portion of the coupled-in light (5) is deflected in the direction of the second optical fiber section (9) and is coupled out in the edge region (16) of the light output surface (10) of the second optical fiber section (9). [2] Lighting device according to claim 1, characterized by that the reflection surface (12) of the reflection section (11) has optical scattering elements (20) in such a region (19, 19', 19") which, if the region were designed as a smooth surface, would reflect the coupled-in light (5) directly without further total reflection to the edge region (16) of the light output surface (10) of the second optical fiber section (9). [3] Lighting device according to claim 1 or 2, characterized bythat the reflection surface (12) has a main area (21) which is smooth and has no optical scattering elements (20). [4] Lighting device according to one of claims 1 to 3, characterized by that the edge region (19, 19', 19") of the reflection surface (12) adjoins at least opposite sides of the main region (21) of the reflection surface (12). [5] Lighting device according to one of claims 1 to 4, characterized by that the optical scattering elements (20) are arranged in an edge region (19, 19', 19") of the reflection surface (12), wherein an edge width (b R ) of the edge region (19, 19', 19") of the reflection surface (12) is larger than an edge region (b A ) of the edge area of the light coupling surface (10). [6] Lighting device according to one of claims 1 to 5, characterized by that the optical scattering elements (20) are designed as a roughening or as micro-scattering elements. [7] Lighting device according to one of claims 1 to 6, characterized by that the optical scattering elements (20) are applied to a surface of the reflection surface (12) by etching or lasering or sandblasting. [8] Lighting device according to one of claims 1 to 7, characterized by that the light output surface (10) of the light guide (1) runs perpendicular to a light exit surface (13) of the first light guide section (7). [9] Lighting device according to one of claims 1 to 8, characterized by that the reflection surface (12) is flat and that the reflection surface (12) encloses an angle of 45° with the light output surface (10) and with the light exit surface (13) of the first light guide section (7). [10] Lighting device according to one of claims 1 to 9, characterized bythat the light guide (1) is designed as a flat light guide with opposite flat sides (3, 3', 3"), at which the coupled light (5) is totally reflected. [11] Lighting device according to one of claims 1 to 10, characterized by that the light output surface (10) of the flat light guide (1) and the reflection surface (12) thereof have a rectangular dimension. [12] Lighting device according to one of claims 1 to 11, characterized by that the reflection surface (12) in projection onto the light coupling surface (8) of the light guide (1) corresponds to at least one dimension of the light coupling surface (8) and that the reflection surface (12) in projection onto the light coupling surface (10) of the light guide (1) corresponds to at least one dimension of the light coupling surface (10). [13] Lighting device according to one of claims 1 to 12, characterized bythat the edge region (19, 19', 19") of the reflection surface (12) containing the optical scattering elements (20) covers the edge region (16) of the light output surface (10) when projected onto the light output surface (10) of the light guide (1). [14] Lighting device according to one of claims 1 to 13, characterized by that the light guide (1) is L-shaped in cross section and has a plurality of LED light sources as light sources (2). [15] Lighting device according to one of claims 1 to 14, characterized by that the light coupling surface (8) is designed in such a way or a collimator is arranged between the light source (2) and the light coupling surface (8) of the light guide (1) in such a way that at least part of a light (5) coupled into the first light guide section (7) is parallelized.

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