Lighting device for motor vehicle

Abstract

The invention relates to a lighting device for a motor vehicle, comprising: a plurality of light sources (10); at least one optical component (12, 13) which is designed as a micro-structured film and / or a micro-structured optical lens; the invention relates to a lighting device (1) for a vehicle, comprising a light source (10), at least one optical component (12, 13), and an optical device (11) for acquiring and / or focusing light, the lighting device being designed such that light (15) emitted by the light source (10) passes through the optical device (11) for acquiring and / or focusing light before passing through the at least one optical component (12, 13).

Description

Technical Field

[0001] The invention relates to a lighting device for a motor vehicle. Background Art

[0002] For signal functions in motor vehicles, such as taillights, brake lights, turn signals, or daytime running lights, the design of taillights or headlights has long been a decisive factor. Since the introduction of LED technology, the design of these lighting devices has become even more important, as small light-emitting diodes, often used in larger numbers, can be used much more flexibly as lighting for signal functions than large incandescent lamps, thus offering a wide range of design possibilities in combination with the selected optical system.

[0003] A variation of LED technology exists in the form of OLED technology, in which the lighting fixtures are not small, point-like, like light-emitting diodes, but rather are larger and planar in design to create the desired luminous area, which can be illuminated very evenly. OLED technology's significantly higher costs compared to LED technology have proven disadvantageous. These high costs are due to complex manufacturing methods, the different moldings required by the design, and small unit quantities. For this reason, the automotive industry places particularly high demands, such as durability against UV stress and forces such as vibration, impact, and shock, as well as thermal resistance in the range of -40°C to +85°C or +100°C. These requirements are significantly more difficult to meet with organic light-emitting diodes than with standard light-emitting diodes.

[0004] This has led to the search for alternative possibilities for achieving a similar design, such as with organic light-emitting diodes (OLEDs), that is, for achieving a particularly uniformly illuminated surface. This is achieved by using light-emitting diodes (LEDs) in conjunction with a planar light guide and upstream optics in the form of microstructured films or thin optical lenses to scatter the light emitted from the light guide. Overall, this provides a flat light module that offers high performance for uniform illumination of the entire surface.

[0005] Just as with organic light-emitting diodes, multiple flat light modules can now be positioned side by side and one after the other in an offset manner when integrated into a rear light element to create a desired, personalized appearance for a signaling function, such as a taillight or rear brake light. Finally, flat light modules can also be implemented as large, planar light elements instead of individual modules. As such a planar lighting device, they can also be used for backlighting displays.

[0006] A lighting device of the type mentioned at the outset is known from DE 10 20 21 12 26 4 A1. The lighting device described therein is designed as a flat light module and has a plurality of light sources designed as light emitting diodes (LEDs) and a planar light conductor comprising an entrance surface and at least one exit surface, wherein the entrance surface is designed as an end surface of the light conductor. The lighting device further comprises two optical lenses, each of which is provided with at least one structured portion, through which the light emitted by the exit surface passes in sequence. The structured portion of the second optical lens in the propagation direction of the light is formed by an array of roof prisms, which are arranged side by side in a first direction and extend parallel to each other in a second direction perpendicular to the first direction. Each of the roof prisms has two inclined side faces, the ends of which form a connecting edge extending in the second direction, wherein the side faces form a roof angle of 90° with each other in the connecting edge.

[0007] An exemplary lighting device according to the prior art, which is designed as a flat light module, comprises Figure 13 and Figure 14 As can be seen, the flat light module has a light source 1 comprising a plurality of light-emitting diodes (LEDs). Furthermore, the flat light module comprises a housing 2 comprising front and rear housing parts 2a, 2b, which are connected to one another by latching. A plate-shaped optical waveguide 3 comprising micro-optics, a white diffusely reflective film 4 behind the optical waveguide 3, and two or three optical components 5a, 5b in the form of micro-optical films in front of the optical waveguide 3 are introduced between the housing parts 2a, 2b. The individual micro-optical components are coordinated with one another, and are therefore responsible for the overall light distribution and efficiency of the system. The principle of this basic design is to provide a light-emitting element comprising a uniformly and evenly illuminated surface. For this purpose, the lighting device comprises a cover plate 6, which serves as the illuminated exit surface of the lighting device.

[0008] Here, the optical component 5a adjacent to the light guide 3 is designed as a diffuser, while the second optical component 5b is designed as a so-called BEF optics. BEF stands for "Brightness Enhancement Film." That is, BEF optics are used to increase the brightness of light passing through the optical component 5b. For this purpose, the BEF optics can be implemented as a film or as a thin, injection-molded optical lens. A system comprising two orthogonally oriented BEF optics can also be provided, in which case the diffuser optics are sometimes omitted.

[0009] The BEF structure known from DE 10 20 22 11 3 05 2 A1 comprises an array of linear roof prisms 7, which are arranged in Figure 15 Each of the roof prisms 7 has a roof angle α of 90°.

[0010] The shown technique or the described configuration of a flat light module comprising light guides and optical lenses and / or optical films in a flat housing and a cover plate is efficient when the height and the width of the flat light module define a large face to be illuminated as a rectangle or a square. Light that is in-coupled into the light guides of the flat light module needs a sufficiently long light path in the light guides in order to enable an efficient system for a uniform illumination of the exit face of the illumination device. If the light path of the light in the light guides is shortened, for example because the module should only have a small height of the illuminated face in general, the light guide efficiency is low. SUMMARY

[0011] Therefore, the problem underlying the present application is to provide an illumination device of the type mentioned at the outset in which an efficient and in particular uniform illumination of the exit face can be achieved despite a narrow exit face.

[0012] This is achieved according to the application by an illumination device of the type mentioned at the outset having the features of the characterizing part of claim 1. The dependent claims relate to preferred designs of the application.

[0013] According to claim 1, the illumination device comprises:

[0014] - a plurality of light sources,

[0015] - at least one optical member, which is configured as a microstructured film and / or a microstructured optical lens, and

[0016] - optical means for light acquisition and / or focusing, wherein the illumination device is designed such that light emitted from the light sources passes through the optical means for light acquisition and / or focusing before passing through the at least one optical member.

[0017] The light sources can in particular be arranged side by side in one row. Alternatively, the light sources can also be arranged in two or more rows that are arranged closely side by side. The light sources can in particular be configured as light emitting diodes (LEDs). The light emitting diodes can be arranged on one common circuit board, which is in particular provided with a white solder resist in order to reflect light that is reflected back in the system again forward.

[0018] By dispensing with a light guide, the at least one optical lens can be illuminated relatively directly by the light sources from the back via the optical means for light acquisition and / or focusing. Thereby, a narrow, in particular largely linear, exit face of the illumination device can also be efficiently illuminated. Furthermore, in such a configuration, the weight and the space requirement of the illumination device can be reduced relative to an illumination device comprising a flat light module.

[0019] The optical element for light capture and / or focusing can be a Fresnel optical element. The Fresnel optical element can have an entrance surface and an exit surface for the light emitted by the light source, wherein the entrance surface and / or the exit surface of the Fresnel optical element can be provided with a structured portion, in particular, a diffuser optical element. The Fresnel optical element can be designed to be very compact, so that the lighting device can have a small installation depth. Furthermore, the structured portion on the Fresnel optical element can contribute to light shaping, in particular, light homogenization.

[0020] Alternatively, the optical device for light capture and / or focusing can be a TIR optical device. In the TIR optical device, light is at least partially guided by total internal reflection. The TIR optical device can have an entrance surface and an exit surface for the light emitted by the light source, wherein the entrance surface and / or the exit surface of the TIR optical device are provided with a structured portion, in particular, a diffuser. The TIR optical device can also be designed to be very compact, so that the lighting device can have a small installation depth. Furthermore, the structured portion on the TIR optical device can also contribute to light shaping, in particular, light homogenization.

[0021] It is possible that the optical device for light capture and / or focusing has a plurality of optical zones, wherein one of the optical zones is assigned to each of the light sources such that the light emitted by the light source passes through the assigned optical zone. Each of the optical zones can have a lens. This ensures that the light from each of the individual light sources is specifically shaped and incident on the at least one optical component.

[0022] The lighting device may include multiple optical components, each configured as a microstructured film and / or a microstructured optical lens. The lighting device is designed so that light emitted from the optical device for light extraction and / or focusing passes through the multiple optical components in sequence. The multiple optical components can collectively ensure desired light scattering and thereby uniform illumination of the exit surface.

[0023] It is possible that the at least one optical component or at least one of the optical components has a diffusing optical system, by which the light can be suitably scattered.

[0024] Alternatively or additionally, it is possible that at least one of the optical components, or at least one of the optical components, includes an array of roof prisms. This creates a BEF optical device. BEF stands for "Brightness Enhancement Film." BEF optical devices are used to increase the brightness of light passing through the optical component.

[0025] Alternatively or additionally, it is possible that at least one of the optical components, or at least one of the optical components, includes an array of light-deflecting prisms, which are designed to deflect the light passing through the optical component so that the average propagation direction of the light in front of the optical component forms an angle different from 0° with the average propagation direction of the light behind the optical component. The corresponding optical component thus includes so-called DTF optics. DTF stands for "Direction Turning Film." Prismatic optics, formed by linear prisms, are provided here that deflect the light at an angle, for example, in a rotatably mounted system, to redirect the light back into the main emission direction. The DTF optics make it possible, in the rotated mounting position of the lighting device, to deflect the light emitted by the light source so that it emerges from the lighting device in a desired main direction parallel to the direction of travel. The prism angles of the light-deflecting prisms can at least substantially correspond to the angle of the mounting position.

[0026] The lighting device may include a cover plate (cover lens), wherein the lighting device is designed so that light, after passing through the at least one optical component, exits the lighting device at least partially through the cover plate. The cover plate may be provided with structuring, such as a diffuser lens. In this way, the cover plate may also contribute to light shaping, in particular light homogenization.

[0027] It is possible that the first surface of the at least one optical component or the first optical component is provided with a diffusion optics system, and the second surface of the at least one optical component or the second optical component is provided with an array of roof prisms. The diffusion optics system can effectively scatter light to improve the uniformity of the illuminated surface. The BEF optics system can increase the brightness of light passing through the optical component. Together, the two surfaces or optical components can ensure efficient illumination of the exit surface of the lighting device.

[0028] Alternatively or additionally, the first face of the at least one optical component, or the first optical component, may be provided with an array of roof prisms arranged side by side in a first direction and extending parallel to one another in a second direction perpendicular to the first direction, and the second face of the at least one optical component, or the second optical component, may be provided with an array of roof prisms arranged side by side in the second direction and extending parallel to one another in the first direction. This interdigitated array of roof prisms improves illumination uniformity and simultaneously slightly increases central light intensity, which is advantageous for the efficient design of signal functions including such optical systems.

[0029] Alternatively or additionally, it is possible to provide one surface of the at least one optical component or a third optical component with an array of light-deflecting prisms. This DTF optical system can additionally deflect the light emitted by the light source in a rotated installation position of the lighting device so that it exits the lighting device in a desired main direction parallel to the direction of travel. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will now be further explained with reference to the accompanying drawings.

[0031] Figure 1 A side view showing a first embodiment of the lighting device according to the present invention;

[0032] Figure 2 Shown in accordance with Figure 1 Detailed view of arrow II in FIG;

[0033] Figure 3 A perspective detailed view showing a second embodiment of the lighting device according to the present invention;

[0034] Figure 4 Shown in accordance with Figure 3 A side view of a detail of the lighting device;

[0035] Figure 5 A perspective detailed view showing a third embodiment of the lighting device according to the present invention;

[0036] Figure 6 Shown in accordance with Figure 5 Another perspective detailed view of the lighting fixture;

[0037] Figure 7 Shown in accordance with Figure 5 Another perspective detailed view of the lighting fixture;

[0038] Figure 8 Shown in accordance with Figure 5 Another perspective detailed view of the lighting fixture;

[0039] Figure 9A side view showing a fourth embodiment of the lighting device according to the present invention;

[0040] Figure 10 A side view showing a fifth embodiment of the lighting device according to the present invention, including a plotted beam path of light;

[0041] Figure 11 Shown in accordance with Figure 10 A side view of a lighting device;

[0042] Figure 12 A side view showing a sixth embodiment of the lighting device according to the present invention, including a plotted beam path of light;

[0043] Figure 13 A perspective view showing a lighting device according to the prior art;

[0044] Figure 14 Shown in accordance with Figure 13 Exploded view of the lighting device;

[0045] Figure 15 Shown by following Figure 13 A cross section of an optical component of an illumination device. DETAILED DESCRIPTION

[0046] In the figures, identical or functionally identical components are provided with the same reference numerals.

[0047] The lighting device depicted in the figure comprises a plurality of light sources 10, an optical device 11 for light acquisition and / or focusing, two optical components 12, 13 in the form of microstructured films and / or microstructured optical lenses, and a cover plate 14 (see Figure 1 Here, the lighting device is designed to allow light 15 emitted from the light source 10 to pass through the optical device 11 for light capture and / or focusing, then pass through the two optical components 12 and 13 and then at least partially exit the lighting device through the cover plate 14.

[0048] It is entirely possible that the lighting device does not include a cover plate 14. Furthermore, more than two optical components 12, 13 or only one optical component 12, 13 may be provided.

[0049] The light source 10 is configured as a light emitting diode (LED). Figure 1 1 shows a circuit board 16 on which the light source 10, which is designed as a light emitting diode, is arranged. The circuit board 16 can be provided with a white solder resist in particular in order to reflect the light reflected back in the system forward again.

[0050] The plurality of LEDs can also have different colors, for example, to implement dual or triple functions. For example, alternating side-by-side arrangements of red and yellow, white and yellow, or white and cyan LEDs, or dual-color LEDs or RGB LEDs are possible. These functions can include, for example, position lights, daytime running lights, and turn indicators, or position lights, daytime running lights, and an automated driving function, the automated driving function requiring the color cyan.

[0051] The light sources 10 are arranged side by side in a row. Alternatively, the light sources 10 can also be arranged in two or more closely arranged rows.

[0052] The optical device 11 for light acquisition and / or focusing has a plurality of optical regions 17 (see Figures 3 to 8 ). Each of the optical regions 17 has a lens. Here, one of the optical regions 17 is configured for each of the light sources 10 so that the light 15 emitted from the light source 10 passes through the configured optical region. For this purpose, the optical device 11 has a lens for the light 15 emitted from the light source 10 (see Figure 4 、 Figure 6 and Figure 8 )'s incident surface 18 and exit surface 19.

[0053] In accordance with Figure 3 and Figure 4 In the embodiment of FIG, the optical element 11 for light capture and / or focusing is designed as a Fresnel optical element. The entrance surface 18 of the Fresnel optical element is flat, while the exit surface 19 is provided with a Fresnel structure to form a lens. It is entirely possible to provide the Fresnel structure on the entrance surface 18 and to design the exit surface 19 flat.

[0054] On the flat surface of the Fresnel optics, a structure not shown can be provided, in particular a structure serving as a diffuser. It is entirely possible to provide a structure, in particular a structure serving as a diffuser, on the surface provided with the Fresnel structure, as an alternative or in addition.

[0055] In accordance with Figures 5 to 8 In the embodiment of FIG, the optical system 11 for light capture and / or focusing is designed as a TIR optical system. The entrance surface 18 and the exit surface 19 are curved to form lenses. It is entirely possible to design one of the two surfaces, in particular the exit surface 19, to be flat. Structures (not shown) may be provided on the entrance surface 18 and / or the exit surface 19, in particular structures serving as diffuser optical elements.

[0056] according to Figure 1 and Figure 2The first optical component 12 of the embodiment of the present invention has a diffuse optical device. The diffuse optical device can be arranged on the incident surface and / or the exit surface of the first optical component 12.

[0057] according to Figure 1 and Figure 2 The second optical component 13 of the embodiment of FIG. 1 has BEF optics. Figure 2 An array 20 of roof prisms 21 forming a BEF optical element is shown, which is arranged on the exit surface of the second optical component 13. It is entirely possible to alternatively or additionally arrange the BEF optical element on the entrance surface of the second optical component 13. In particular, it can be provided that the arrays 20 of roof prisms 21 on the entrance and exit surfaces of the second optical component 13 intersect one another, i.e., the ridges of the roof prisms 21 on the entrance surface extend in a first direction, and the ridges of the roof prisms 21 on the exit surface extend in a second direction perpendicular to the first direction.

[0058] according to Figure 10 and Figure 11 The second optical component 13 of the embodiment has a DTF optical device. Figure 11 An array 22 of prisms 23 for deflecting light forming a DTF optical device is shown, said array being arranged on the exit surface of the second optical component 13. The prisms 23 are designed to deflect the light passing through the second optical component 13 such that the average propagation direction of the light in front of the optical component forms an angle with the average propagation direction of the light behind the optical component. In the embodiment described, said angle is approximately 30° (see Figure 10 and Figure 11 ). The angle may also have other sizes.

[0059] It is entirely possible to arrange the DTF optics alternatively or additionally on the entrance face of the second optical component 13. It is also possible to arrange an array 22 of light-deflecting prisms 23 both on the first optical component 12 and on the second optical component 13, said array serving as the DTF optics (see Figure 14 ).

[0060] Furthermore, it is possible to provide the cover plate 14 with structuring, for example diffuser optics.

[0061] The lighting device can have different variations of optical components or functional structures. Some examples are given below.

[0062] - Diffusing optics, followed by BEF optics with horizontal orientation, followed by BEF optics with vertical orientation.

[0063] - Diffusing optics, followed by BEF optics with horizontal orientation, followed by BEF optics with vertical orientation, followed by a cover plate with or without structuring.

[0064] - A BEF optic with horizontal orientation, followed by a BEF optic with vertical orientation.

[0065] - BEF optics with horizontal orientation, followed by BEF optics with vertical orientation, followed by a cover plate with or without structuring.

[0066] - Diffuse optics, followed by BEF optics with horizontal orientation, followed by DTF optics.

[0067] - Diffusing optics, followed by BEF optics with horizontal orientation, followed by DTF optics, followed by a cover plate with or without structuring.

[0068] This list is merely exemplary and should not be understood as exhaustive. Other possible combinations of optical components or functional structures of the lighting device are also possible.

[0069] Reference Signs List

[0070] 1 light source

[0071] 2 shell

[0072] 2a, 2b housing parts

[0073] 3. Photoconductor

[0074] 4Reflective film

[0075] 5a, 5b are optical components composed of micro-optical films

[0076] 6 Cover

[0077] 7 Roof prism of optical component 5b

[0078] 10 light sources

[0079] 11 Optical devices for light acquisition and / or focusing

[0080] 12 first optical member

[0081] 13 Second optical member

[0082] 14 cover

[0083] 15 Light emitted from a light source

[0084] 16 circuit boards

[0085] 17 Optical area of ​​optical device for light acquisition and / or focusing

[0086] 18 entrance face of an optical device for light acquisition and / or focusing

[0087] 19 exit face of an optical device for light acquisition and / or focusing

[0088] 20 array of roof prisms

[0089] 21 roof prism

[0090] 22 array of prisms for deflecting light

[0091] 23 prism for deflecting light

[0092] α roof angle of a roof prism

Claims

1. A lighting device for a motor vehicle, comprising: - a plurality of light sources (10), at least one optical component (12, 13) which is designed as a microstructured film and / or a microstructured optical lens, and - an optical device (11) for light capture and / or focusing, wherein the lighting device is designed so that light (15) emitted by the light source (10) passes through the optical device (11) for light capture and / or focusing before passing through the at least one optical component (12, 13).

2. The lighting device according to claim 1, characterized in that The optical device (11) for light acquisition and / or focusing is a Fresnel optical device.

3. The lighting device according to claim 2, characterized in that The Fresnel optical element has an entrance surface (18) and an exit surface (19) for the light (15) emitted by the light source (10), wherein the entrance surface (18) and / or the exit surface (19) of the Fresnel optical element is provided with a structuring, in particular with a diffuser optical element.

4. The lighting device according to claim 1, characterized in that The optical device (11) for light extraction and / or focusing is a TIR optical device.

5. The lighting device according to claim 4, characterized in that The TIR optical element has an entrance surface (18) and an exit surface (19) for the light (15) emitted by the light source (10), wherein the entrance surface (18) and / or the exit surface (19) of the TIR optical element is provided with a structuring, in particular a diffuse optical element.

6. The lighting device according to any one of claims 1 to 5, characterized in that The optical device (11) for light acquisition and / or focusing has a plurality of optical areas (17), wherein one of the optical areas (17) is configured for each of the light sources (10), so that light (15) emitted from the light source (10) passes through the configured optical area (17).

7. The lighting device according to any one of claims 1 to 6, characterized in that The lighting device has a plurality of optical components (12, 13), which are configured as microstructured films and / or microstructured optical lenses, wherein the lighting device is designed to allow light (15) emitted from the optical device (11) for light acquisition and / or focusing to pass through the plurality of optical components (12, 13) in sequence.

8. The lighting device according to any one of claims 1 to 7, characterized in that The at least one optical component (12, 13) or at least one of the optical components (12, 13) has diffusing optics.

9. The lighting device according to any one of claims 1 to 8, characterized in that The at least one optical component (12, 13) or at least one of the optical components (12, 13) has an array (20) of roof prisms (21).

10. The lighting device according to any one of claims 1 to 9, characterized in that The at least one optical component (12, 13) or at least one of the optical components (12, 13) has an array (22) of light-deflecting prisms (23), which are designed to deflect light (15) passing through the optical component (12, 13) so that an average propagation direction of the light (15) in front of the optical component (12, 13) forms an angle different from 0° with an average propagation direction of the light (15) behind the optical component (12, 13).

11. The lighting device according to any one of claims 1 to 10, characterized in that The lighting device comprises a cover plate (14), wherein the lighting device is designed so that light, after passing through the at least one optical component (12, 13), at least partially emerges from the lighting device through the cover plate (14).

12. The lighting device according to claim 11, characterized in that The cover plate (14) is provided with structuring, for example diffuser optics.

13. The lighting device according to any one of claims 1 to 12, characterized in that The first surface of the at least one optical component (12, 13) or the first optical component (12, 13) is provided with an array (20) of roof prisms (21), which are arranged side by side along a first direction and extend parallel to each other along a second direction perpendicular to the first direction, and the second surface of the at least one optical component (12, 13) or the second optical component (12, 13) is provided with an array (20) of roof prisms (21), which are arranged side by side along the second direction and extend parallel to each other along the first direction.

14. The lighting device according to any one of claims 1 to 13, characterized in that The first face of the at least one optical component (12, 13) or the first optical component (12, 13) is provided with diffuse optics and the second face of the at least one optical component (12, 13) or the second optical component (12, 13) is provided with an array (20) of roof prisms (21).

15. The lighting device according to claim 13 or 14, characterized in that One surface of the at least one optical component (12, 13) or a third optical component (12, 13) is provided with an array (22) of prisms (23) for deflecting light.

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