Lighting device for a motor vehicle and motor vehicle having such a lighting device

Abstract

Lighting device (2) for a motor vehicle (1), comprising at least one light source (5) and a transparent disc (7) through which the light (8) generated by the at least one light source (5) passes and on which a planar layer (17) having several interruptions (19) is provided, wherein a scattering of the light (8) generated by the at least one light source (5) caused by the layer (17) is stronger than a scattering of the light (8) generated by the at least one light source (5) caused by the disc (7).

Description

[0001] The present invention relates to a lighting device for a motor vehicle, comprising at least one light source and a transparent disc through which the light generated by the at least one light source passes and on which a planar layer having several interruptions is provided.

[0002] Lighting devices on motor vehicles, designed as exterior lights, serve two purposes: firstly, to illuminate the area surrounding the vehicle, improving the driver's visibility; and secondly, to make the vehicle more visible to other road users. In particular, the rear headlights of a motor vehicle serve to make the vehicle recognizable to traffic approaching from behind.

[0003] Corresponding lighting devices typically include a light source that generates the light emitted into the surroundings. This light typically exits through an outer pane of the lighting device. To achieve a desired effect on the light, the outer pane often has a coating or layer that allows a property of the light to be modified.

[0004] For example, DE 10 2010 032 190 A1 discloses a lighting unit for a motor vehicle, comprising a transparent transmissive element that forms an outer contour of the lighting unit in a light-emitting area. The transmissive element has a decorative coating, such as a colored lacquer. To allow light to pass through the lighting unit, the coating has perforations with fine openings through which the light passes.

[0005] Another concept for a lighting device for a motor vehicle is known from DE 38 43 522 A1, comprising a diffuser lens with a metallic coating applied thereto. The coating may only be partially applied to the diffuser lens.

[0006] The present invention aims to provide an improved concept in connection with a lighting device of a motor vehicle, especially with regard to the most advantageous emission characteristics.

[0007] According to the invention, the problem is solved in a lighting device of the type mentioned at the outset in that a scattering of the light generated by the at least one light source caused by the layer is stronger than a scattering of the light generated by the at least one light source caused by the disk.

[0008] In the lighting device according to the invention, the light generated by the at least one light source passes through the disk only in the area of ​​the interruptions, and otherwise through both the disk and the layer. In other words, the light passing through the disk in the area of ​​the interruptions passes only through the disk material, whereas the remaining light passes through both the disk material and the layer material. The scattering of the light that passes only through the disk is less pronounced than the scattering of the light that passes through both the disk and the layer. Scattering refers to a diffuse deflection of the light with respect to its direction of propagation.

[0009] The lighting device according to the invention advantageously achieves an increased brightness in certain spatial directions, resulting from the light emitted by the lighting device. These are typically directions that are particularly relevant during the operation of the vehicle, for example, straight ahead to the rear. Although this increase in brightness occurs at the expense of brightness in other spatial directions, this is acceptable because certain spatial directions are particularly relevant or because particularly high demands are placed on the brightness in certain directions.

[0010] To make this advantage more understandable, aspects regarding preferred embodiments of the lighting device according to the invention are now assumed, which in this case is designed as a rear headlight, whereby these embodiments can also be implemented independently of each other.

[0011] According to one of these preferred embodiments, the light passing through the disk, particularly with respect to light rays incident perpendicularly on the disk, is intended to pass through it at least substantially without scattering. Naturally occurring control effects, such as those resulting from microscopic irregularities on the disk's surface, are disregarded and neglected.

[0012] According to another of these preferred embodiments, the light passing through the layer is scattered uniformly and to a maximum extent. If the disk, and thus the layer, extends along a flat surface, this means that the light passing through the layer is scattered uniformly in all directions of the hemisphere that is arranged on the exit or viewing side of the disk and the layer.

[0013] If the disc and the layer extend along a vertical and a transverse direction of the vehicle, i.e., perpendicular to a longitudinal direction, and if the light incident on the disc propagates along the longitudinal direction of the vehicle, this configuration results in the portion of the light that passes through the disc in the area of ​​the interruptions propagating unimpeded and straight ahead along a main direction of radiation. This direction corresponds to the direction of propagation of the parallel light before it strikes the disc and preferably extends straight back along the longitudinal direction of the vehicle. In contrast, the portion of the light that does not pass through the disc in the area of ​​the interruptions, and thus also through the layer, is scattered uniformly in all directions.

[0014] As a consequence, the brightness of the lighting device appears higher to an observer located along the main emission direction compared to the case where, according to a non-inventive embodiment, the interruptions are not provided. This effect also occurs with respect to the other spatial directions that are perpendicular to the main emission direction. Thus, the brightness of the lighting device with respect to the main emission direction results both from the portion of the light that passes through the disk in the area of ​​the interruptions and from the portion of the light that passes through the layer and is scattered towards the main emission direction. In contrast, the brightness of the lighting device with respect to the other spatial directions that are perpendicular to the main emission direction results only from the portion of the light that passes through the layer and is scattered towards the respective spatial direction.This ensures that the main direction of emission provides increased brightness and thus improved visibility of the lighting device, while still ensuring sufficient visibility of the lighting device in all other directions due to the light emitted in those directions.

[0015] The at least one light source is preferably at least one light-emitting diode (LED). White and / or colored light can be generated by the light source. The brightness of the light generated by the at least one light source can be varied. To control the light source, particularly with regard to color and / or brightness, it can be connected to a control unit of the lighting system or the vehicle, which is configured to generate control signals directed at it and output them to the at least one light source. This control can be based on user-defined control commands and / or control commands generated during autonomous driving of the vehicle.

[0016] The lighting device according to the invention can comprise an outer pane through which the light generated by the at least one light source exits the lighting device. The lighting device can thus have a housing that defines an interior space, wherein components of the lighting device are arranged in the interior space, such as the at least one light source and at least one optical unit, which will be explained further below. The outer pane can form a light-exit area of ​​the lighting device, specifically a section of the housing through which the light exits to the outside. The housing can be made of a metal and / or a plastic, optionally with the exception of the outer pane. Apart from the outer pane, the housing is preferably opaque. The pane can comprise an inner surface facing the interior and an outer surface facing the surroundings of the motor vehicle.The layer can be located on the inner surface or the outer surface.

[0017] According to a further development, the pane can be the outer pane. In this embodiment, the pane, or rather the outer pane, synergistically fulfills several functions: firstly, the function described above regarding the desired radiation properties, and secondly, protection of the interior from unwanted external influences such as moisture and / or dirt. This embodiment saves components and thus reduces weight, costs, and installation space.

[0018] Alternatively, the disc can be an intermediate light disc arranged between the at least one light source and the outer disc. Although the advantages just described regarding the alternative embodiment are not present in this configuration, it nevertheless fulfills the purpose of the invention.

[0019] The lighting device according to the invention can comprise at least one carrier plate on which the multiple light sources are arranged. The carrier plate can also be referred to as a circuit board and, in particular, can form a printed circuit board. The carrier plate can be made of a plastic. The carrier plate preferably extends along a flat surface. Particularly when the carrier plate is the printed circuit board, the light sources, especially the LEDs, can be electrically connected or soldered to it.

[0020] It is conceivable that the lens and the mounting plate are arranged opposite each other in or on the interior of the lighting device, particularly with respect to the vehicle's longitudinal direction and / or the main beam direction. In particular, if both the lens and the mounting plate extend along a flat surface, then the lens and the mounting plate can be arranged parallel to each other.

[0021] The lighting device according to the invention particularly preferably comprises at least one optical unit by means of which a path of light generated by the at least one light source is defined within the interior of the lighting device. The optical unit causes an otherwise straight path of light to be modified as desired. The path of the light is preferably influenced by refraction and / or reflection processes effected by the optical unit. The path is preferably defined by the optical unit such that a large proportion, or at least substantially all, of the light generated by the at least one light source reaches the light output area.

[0022] It is conceivable that at least one optical unit causes at least a portion of the light generated by the at least one light source to strike the disk and / or the layer in a substantially parallel manner. The direction of propagation of this parallelized light then corresponds to the main emission direction already explained above. In this case, all the light can be parallelized with respect to a common direction of propagation.

[0023] It is conceivable that the optical unit, or at least one of the optical units, is a lens or an optical fiber. The lens can be a converging lens. The optical fiber can be at least one optical fiber, for example, made of glass or plastic. The optical fiber, which is particularly elongated, preferably comprises at its end faces an input surface located in the region of the light source, through which the light is introduced into the optical fiber, and an output surface located in the region of the disk or layer, through which the light is emitted from the optical fiber.

[0024] The optical unit, or at least one of the optical units, can be arranged between the at least one light source, in particular the carrier plate, and the disk. Alternatively, or in addition, the optical unit, or at least one of the optical units, can be configured as a section of the disk, in particular one opposite the layer. Thus, the optical unit can form or comprise a curved and / or angled surface of the disk. The layer can be arranged on one of the two surfaces of the disk, and it is conceivable that the section of the disk forming the at least one optical unit is arranged on the surface of the disk opposite the layer.

[0025] Regarding the interruptions, it is conceivable that they are linear. The extent along a longitudinal direction of each interruption is therefore significantly greater than its extent along a lateral direction. Thus, regarding the production of the layer, it can be applied to the entire surface of the disk, with the interruptions, particularly the linear ones, being introduced afterward. A tool can be used for this purpose, with which the layer is removed in the area of ​​the interruptions. However, the interruptions and the layer can also be created simultaneously, for example, by means of a rasterized printing process.

[0026] Preferably, the linear interruptions, or at least a portion thereof, are arranged parallel and, optionally, equidistant from one another. The distance between the interruptions can be a maximum of 1 mm. It is also conceivable that a first set and a second set of linear interruptions are provided, each running parallel to and, optionally, equidistant from one another. The linear interruptions of the two sets can be angled, in particular perpendicular, to each other. Consequently, the linear interruptions can form a grid-like pattern.

[0027] Alternatively, or in addition, the interruptions can form a pattern. The pattern can be repeating. The pattern can be such that the layer has several island-like areas, with the gaps between these areas forming the interruptions. The areas can have a submillimeter dimension.

[0028] The coating can be a layer of paint. In particular, if the lighting device is a rear light and / or a brake light, the coating can be red. Other colors are also conceivable, such as white, if the lighting device is, for example, a headlight or a reversing light; yellow, if the lighting device is, for example, a turn signal or warning light on a construction vehicle; blue, if the lighting device is, for example, a warning light on an emergency vehicle; or green, if the lighting device is, for example, a warning light on a special vehicle, such as a fire engine. The coating can be applied wet and then dried. It is also conceivable that the coating could be applied using a halftone printing process.

[0029] The layer can be a metal layer. The metal layer can be made of aluminum. The metal layer is preferably sufficiently thin, approximately in the micrometer range, so that, on the one hand, light can pass through the metal layer, for example, in low ambient light conditions such as at night, while on the other hand, ambient light is reflected by the metal layer to create a metallic optical effect, for example, in high ambient light conditions such as during the day. Preferably, the metal layer is vapor-deposited onto the disk.

[0030] It is conceivable that the layer is a roughened surface of the disc. The layer can form a matte finish on the disc. Accordingly, the disc exhibits lower roughness in the area of ​​the interruptions than in the rest of the area. Preferably, the disc is smooth in the area of ​​the interruptions. Microscopically, the roughness forms irregularities on the surface of the disc, leading to diffuse scattering and reflection effects. The roughened surface of the disc can be produced by grinding and / or sandblasting.

[0031] The layer can be a surface structure introduced into the surface of the disc using a tool, comprising raised areas and depressions whose dimensions are particularly in the submillimeter range. Similar to a roughened surface, the introduced surface structure causes diffuse scattering and reflection effects. The tool can be an embossing tool. Especially if the disc is made of a plastic, the surface structure can be formed when the disc is within a temperature range that allows for non-destructive deformation of this material.

[0032] It is conceivable that the pane consists of transparent glass. In particular, if the layer is intended as the applied surface structure of the pane, the pane can be made of a transparent plastic, for example, acrylic glass or PMMA.

[0033] Furthermore, the present invention relates to a motor vehicle. In a motor vehicle according to the invention, the problem is solved by the fact that it comprises at least one lighting device designed as an exterior light, as described above. An exterior light is understood to be a lighting device arranged on the outside of the motor vehicle or on an outer skin of the motor vehicle. Thus, the light generated by the exterior light is emitted into the surroundings of the motor vehicle. The lighting device, or at least one of the lighting devices, can be a rear headlight or a front headlight of the motor vehicle. All advantages, features, and aspects explained in connection with the lighting device according to the invention are equally transferable to the motor vehicle according to the invention, and vice versa.

[0034] Further advantages and details of the present invention will become apparent from the exemplary embodiments described below and from the figures. These show schematically: Fig. 1 a schematic, side view of a motor vehicle according to an embodiment of the invention, comprising two lighting devices according to an embodiment of the invention, each according to an embodiment; Fig. 2 a schematic longitudinal section through a lighting device according to a first embodiment of the invention; Fig. 3 a perspective view of a section of a disc and a layer of the lighting device of the Fig. 2 Fig. 4 shows a schematic longitudinal section through a lighting device according to a second embodiment of the invention, and Fig. 5 shows a perspective view of a section of a disk and a layer of the lighting device. Fig. 4 .

[0035] Fig. 1Figure 1 shows a schematic, side view of a motor vehicle 1 according to an embodiment of the invention. The motor vehicle 1 comprises several lighting devices 2 according to the invention, designed as exterior lights, each according to an embodiment. Thus, two front headlights 3 and two rear headlights 4 are provided as the lighting devices 2, wherein in Fig. 1Due to the perspective of this drawing, only a front headlight 3 and a rear headlight 4 are visible. To control the lighting devices 2, specifically with regard to the color and brightness of the light 8 generated by light sources 5 of the respective lighting device 2, each lighting device 2 is connected to a control device 6 of the motor vehicle 1. This control device is configured to generate control signals and output them to the lighting devices 2. This control can be carried out based on user-specified control commands or those available during autonomous driving operation of the motor vehicle 1. The front headlight 3 provides forward illumination along a longitudinal direction 11 of the vehicle, and the rear headlight 4 provides rearward illumination along the same longitudinal direction 11.

[0036] Fig. 2Figure 1 shows a highly schematic longitudinal section through a lighting device 2 according to a first embodiment of the invention. This lighting device 2 can be the rear headlight 4 of the motor vehicle 1. Fig. 1 The lighting device 2 comprises a light source 5 and a transparent disc 7 through which the light 8 generated by the light source 5 is emitted outwards. The light source 5 is arranged within a housing 9 of the lighting device 2 made of an opaque plastic, with the disc 7 forming part of the housing 9, i.e., an outer disc 12 of the lighting device 2, as well as a light emission area 10. Instead of the one based on the Fig. 2 In the configuration shown, where disk 7 forms the outer disk 12, disk 7 can be a separate component located between the light source 5 and the outer disk 12.

[0037] An optical unit 14 is arranged within an interior space 13 of the lighting device 2, bounded by the housing 9 and the outer pane 12. This optical unit 14 is a converging lens positioned between the light source 5 and the pane 7. The optical unit 14 defines a path for the light 8 such that the light 8 strikes the pane 7 in a parallel direction. The direction of propagation of the parallelized light 8 extends along a main emission direction 15, which runs parallel to the longitudinal direction 11 of the vehicle, i.e., straight ahead to the rear with respect to the vehicle 1.

[0038] With further reference to the Fig. 3Figure 1, which shows a perspective view of part of the disc 7, is followed by an explanation of the functionality of the lighting device 2 with regard to the desired emission characteristics. A planar layer 17 is provided on an outer surface 16 of the disc 7 facing away from the interior 13. However, the layer 17 is not continuous but is formed from several island-like areas 18, so that the layer 17 has interruptions 19 that separate the areas 18 from one another. The size of the areas 18 is in the submillimeter range, so that this structure is no longer clearly visible at a sufficiently large distance from the vehicle 1. It should be noted here that the layer 17 can also be arranged on an inner surface of the disc 7 facing away from the outer surface 16.

[0039] Regarding the influence of the disk 7 and the layer 17 on the light 8, it is provided that any scattering of the light 8 generated by the light source 5 caused by the layer 17 is stronger than any scattering of the light 8 generated by the at least one light source 5 caused by the disk 7, which is made of glass or a plastic such as acrylic glass. Specifically, it is provided that no scattering of the light 8 occurs in the area of ​​the disk 7, whereas in the area of ​​the layer 17 the light is scattered uniformly with respect to the Fig. 2The light is scattered at least partially in the directions of the space pointing to the right. It follows that the portion of the light 8 that passes through the disk 7 in the area of ​​the openings 19 does not pass through the layer 17, but propagates unhindered along the main emission direction 15. In contrast, the portion of the light 8 that does not pass through the disk 7 in the area of ​​the openings 19 reaches the layer 17, which, due to the scattering that occurs, diffusely deflects this portion of the light 18 in all directions of emission. The light 8 passing through the disk 7 in the area of ​​the openings 19 thus propagates only through the material of the disk 7, whereas the remaining light 8 propagates through both the material of the disk 7 and the material of the layer 17.This results in the brightness of the lighting device 2 with respect to the main emission direction 15 being higher than the brightness of the lighting device 2 with respect to the other spatial directions angled on the main emission direction 15. Specifically, the greatest brightness and thus the best visibility of the lighting device 2 is present with respect to the main emission direction 15, whereby sufficient visibility of the lighting device 2 is also given with respect to the other spatial directions due to the light 8 emitted therein.

[0040] Regarding the linear design of the interruptions 19, which form a repeating grid pattern, it should be noted that this configuration is merely an example. Alternatively, curved interruptions 19 and / or continuous areas 18 could also be provided. With respect to the layer 17, in the present embodiment, it is a colored layer applied by means of color printing, the color being, for example, red, possibly the same as the light 8 itself. Alternatively, the layer 17 could be a metal layer that is sufficiently transparent or translucent with respect to the light 8, while also reflecting ambient light from the outside. The metal layer could be produced by vapor deposition of a metal, such as aluminum, onto the disk 7.

[0041] Now, attention will be turned to the Figures 4 and 5 Reference was made to the fact that the Figures 2 and 3The figures correspond to, but show a second embodiment of the lighting device 2 according to the invention. In principle, all aspects explained in connection with the first embodiment of the lighting device 2, in particular those concerning the increased brightness along the main emission direction 15, are transferable to the second embodiment, unless they expressly deviate from this.

[0042] In the second embodiment of the lighting device 2, several light sources 5, designed as LEDs, are provided and arranged on a flat carrier plate 20. The carrier plate 20 is a circuit board onto which the light sources 5 are soldered. Furthermore, in this embodiment, several lenses are provided as optical units 14 for aligning the light 8. Regarding the optical units 14, it should be noted that these can alternatively also be used as light guides, for example, as optical fibers, by means of which the light from the light sources 5 is guided to the disk 7 and the layer 17, thereby aligning the light 8. Another aspect concerning the optical units 14 relates to the [missing information] in the Fig. 4The indicated circumstance is that these can also be curved sections 21 of the disk 7. These sections 21 are preferably provided on the surface facing away from the layer 17, i.e., the inner surface of the disk 7.

[0043] Another difference from the first embodiment concerns the specific design of layer 17. In the second embodiment, this is a roughened surface of the disk 7, which was produced, for example, by sanding or sandblasting, which in the Fig. 5 as indicated by the dotted area. Alternatively, layer 17 can be a surface structure comprising raised areas and indentations introduced into the outer surface 16 of the disk 7 by means of a tool, which may have been introduced into the outer surface 16 in particular by means of an embossing tool.

Claims

1. Lighting device (2) for a motor vehicle (1), comprising at least one light source (5) and a transparent disc (7) through which the light (8) generated by means of the at least one light source (5) passes and on which a planar layer (17) having several openings (19) is provided, characterized by that a scattering of the light (8) generated by the at least one light source (5) caused by the layer (17) is stronger than a scattering of the light (8) generated by the at least one light source (5) caused by the disk (7).

2. Lighting device (2) according to claim 1, characterized by an outer pane (12), throughthe light (8) generated by means of the at least one light source (5) exits the lighting device (2), wherein the disk (7) is either the outer disk (12) or an intermediate light disk arranged between the at least one light source (5) and the outer disk (12).

3. Lighting device (2) according to claim 1 or 2, characterized by at least one carrier plate (20) on which the multiple light sources (5) are arranged.

4. Lighting device (2) according to one of the preceding claims, characterized by at least one optical unit (14) by means of which a path of light (8) generated by means of the at least one light source (5) is defined in the interior (13) of the lighting device (2).

5. Lighting device (2) according to claim 4, characterized by thatthe at least one optical unit (14) causes at least part of the light (8) generated by the at least one light source (5) to strike the disk (7) and / or the layer (17) in a manner that is at least substantially parallel.

6. Lighting device (2) according to claim 4 or 5, characterized by that the optical unit (14) or at least one of the optical units (14) is a lens or a light guide, in particular an optical fiber.

7. Lighting device (2) according to one of claims 4 to 6, characterized by that the optical unit (14) or at least one of the optical units (14) is arranged between the at least one light source (5), in particular the carrier plate (20), and the disk (7), or is designed as a section of the disk (7), in particular opposite the layer (17).

8. Lighting device (2) according to one of the preceding claims, characterized by thatthe interruptions (19) are linear and / or form a pattern, in particular a repeating pattern.

9. Lighting device (2) according to one of the preceding claims, characterized by that layer (17) is a paint layer.

10. Lighting device (2) according to any one of claims 1 to 8, characterized by that the layer (17) is a metal layer.

11. Lighting device (2) according to any one of claims 1 to 8, characterized by that the layer (17) is a roughened surface of the disk (7).

12. Lighting device (2) according to any one of claims 1 to 8, characterized by that The layer (17) is a surface structure comprising elevations and depressions, introduced into the surface of the disk (7) by means of a tool.

13. Lighting device (2) according to one of the preceding claims, characterized by thatthe disc (7) consists of a transparent glass or a transparent plastic, in particular an acrylic glass.

14. Motor vehicle (1) comprising at least one lighting device (2) designed as an external light according to one of the preceding claims.

15. Motor vehicle (1) according to claim 14, characterized by that the lighting device (2) or at least one of the lighting devices (2) is a front headlight (3) or a rear headlight (4) of the motor vehicle (1).

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