Lighting device for a motor vehicle

Abstract

Lighting device for a motor vehicle, comprising a plurality of light sources (10), at least one optical component (12, 13) designed as a microstructured film and / or as a microstructured optical disk, and optics (11) for light detection and / or focusing, wherein the lighting device is arranged so that light (15) emanating from the light sources (10) passes through the optics (11) for light detection and / or focusing before passing through the at least one optical component (12, 13).

Description

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

[0002] For the signaling functions of a motor vehicle, such as taillights, brake lights, turn signals, or daytime running lights, in taillights or headlights, design has long been a determining factor. The design of these lighting devices has become even more important since the introduction of LED technology, because the small light-emitting diodes, which are often used in larger numbers, can be used much more flexibly as the light source for a signaling function than a large incandescent bulb, thus offering a wide variety of design possibilities in conjunction with the chosen optical system.

[0003] A variation of LED technology is OLED technology, in which the light source is not a small, point-like element like a standard LED, but rather a larger, more diffused surface to create a desired, highly homogeneous illumination area. A disadvantage of OLED technology is its significantly higher cost compared to LED technology. This high cost is due to a complex manufacturing process, the varying shapes required by the design, and low production volumes. Furthermore, the automotive sector has specific, stringent requirements, such as resistance to UV radiation and stresses like vibrations, shocks, and shaking, as well as temperature resistance ranging from -40°C to +85°C or +100°C. These requirements are considerably more difficult for an organic light-emitting diode to meet than for standard LEDs.

[0004] This leads to a search for alternative methods to achieve a design similar to that of organic light-emitting diodes (OLEDs), particularly a homogeneously illuminated surface. This is achieved by using light-emitting diodes (LEDs) with a flat light guide and upstream optics, in the form of microstructured films or thin optical discs, to diffuse the light emitted from the light guide. The result is a flat-light module that offers high performance with homogeneous illumination of the entire surface.

[0005] Just as with organic light-emitting diodes (OLEDs), when integrated into a rear light, several flat-light modules can be positioned offset, side by side, and one behind the other to create the desired individual appearance of the signal function, such as the taillight or brake light. Finally, instead of individual modules, a flat-light module can also be designed as a large, flat lighting element. As such a flat lighting device, it can also be used to backlight displays.

[0006] A lighting device of the type mentioned above is known from DE 10 2021 122 264 A1. The lighting device described therein is designed as a flat-light module and comprises a plurality of light sources designed as light-emitting diodes (LEDs) and a planar light guide with an entry surface and at least one exit surface, wherein the entry surface is designed as the end face of the light guide. The lighting device further comprises two optical disks, each provided with at least one structure, through which the light emanating from the exit surface passes successively. The structure of the second optical disk in the direction of light propagation 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 flanks, the ends of which form a connecting edge extending in the second direction, with the flanks enclosing a roof angle of 90° in the connecting edge.

[0007] An exemplary lighting device designed as a flat-light module according to this state of the art is made of Fig. 13 and Fig. Figure 14 shows that this flat-light module comprises a light source 1, which has several light-emitting diodes (LEDs). The flat-light module further comprises a housing 2 with a front and a rear housing part 2a, 2b, which are connected to each other by a snap-fit ​​connection. Between the housing parts 2a, 2b are inserted a plate-shaped light guide 3 with micro-optics, a white, diffusely reflective film 4 behind the light guide 3, and two or three optical components 5a, 5b designed as micro-optical films in front of the light guide 3, which together are responsible for the light distribution and efficiency of the system by means of the individual micro-optical components being coordinated with each other. The principle of this basic structure is to provide a lighting element with a uniformly, homogeneously illuminated surface. For this purpose, the lighting device includes a cover plate 6, which serves as the illuminated emission surface of the lighting device.

[0008] The optical component 5a adjacent to the light guide 3 is designed as a diffuser, whereas the second optical component 5b is designed as a so-called BEF optic. BEF stands for "Brightness Enhancement Film" in this context. The BEF optic thus serves to increase the brightness of the light passing through the optical component 5b. The BEF optic can be implemented on a film or as a thin injection-molded optical disc. Systems with two BEF optics, aligned orthogonally to each other, can also be used, in which case the diffuser optic is sometimes omitted.

[0009] The BEF structure known from DE 10 2022 113 052 A1 has an array of linear roof prisms 7, which in Fig. Figure 15 is shown. Each of the roof prisms 7 has a roof angle α of 90°.

[0010] The technology shown, specifically the design of the flat-light modules with light guides and optical discs and / or optical films in a flat housing and a cover plate, is efficient when the height and width of the flat-light module define a large illuminated area as a rectangle or square. The light coupled into the light guide of the flat-light module requires a sufficiently long optical path within the light guide to enable an efficient system for homogeneous illumination of the emitting surface of the lighting device. If the optical path of the light within the light guide is reduced, for example, because the module is intended to have only a small height for the illuminated area, the light guide becomes inefficient.

[0011] The problem underlying the present invention is therefore the creation of a lighting device of the type mentioned at the outset, in which, despite a narrow exit surface, efficient and, in particular, homogeneous illumination of the exit surface is made possible.

[0012] According to the invention, this is achieved by a lighting device of the type mentioned at the outset, having the characterizing features of claim 1. The dependent claims relate to preferred embodiments of the invention.

[0013] According to claim 1, the lighting device comprises - a plurality of light sources, - at least one optical component designed as a microstructured film and / or as a microstructured optical disk, as well as - an optic for light detection and / or focusing, wherein the lighting device is configured to allow light emanating from the light sources to pass through the optic for light detection and / or focusing before passing through the at least one optical component.

[0014] The light sources can be arranged side by side in a single row. Alternatively, they can be arranged in two or more closely spaced rows. The light sources can be designed as light-emitting diodes (LEDs). The LEDs can be mounted on a common circuit board, which is coated with a white solder mask to reflect light that is reflected back within the system.

[0015] By eliminating the need for a light guide, at least one optical disc can be backlit relatively directly by the light sources via the optics for light capture and / or focusing. This allows for efficient illumination of even a narrow, and especially a largely linear, emission surface of the lighting device. Furthermore, this design reduces the weight and installation space required for the lighting device compared to lighting devices with a flat-light module.

[0016] The optics for light capture and / or focusing may be a Fresnel lens. This Fresnel lens may have an inlet and an outlet for the light emitted from the light sources, and the inlet and / or outlet surfaces of the Fresnel lens may be textured, particularly with a diffuser. A Fresnel lens can be designed to be very compact, allowing the lighting device to have a shallow installation depth. Furthermore, a textured surface on the Fresnel lens can contribute to light shaping, especially to light homogenization.

[0017] Alternatively, the optics for light capture and / or focusing can be a TIR optic. In a TIR optic, the light is guided, at least partially, by total internal reflections. The TIR optic can have an entry surface and an exit surface for the light emitted from the light sources, with the entry surface and / or the exit surface of the TIR optic being provided with a structure, in particular with a diffuser. A TIR optic can also be designed to be very compact, allowing the lighting device to have a shallow installation depth. Furthermore, a structure on the TIR optic can also contribute to light shaping, in particular to light homogenization.

[0018] The optical system for light capture and / or focusing may comprise multiple optical zones, with each light source assigned to one of these zones in such a way that the light emitted from the light source passes through its assigned zone. Each optical zone may contain a lens. This ensures that the light from each individual light source is specifically shaped and strikes at least one optical component.

[0019] The lighting device may comprise several optical components designed as microstructured films and / or microstructured optical disks, the lighting device being configured so that the light exiting the optics for light capture and / or focusing passes sequentially through the majority of the optical components. Together, the multiple optical components can ensure the desired light diffusion and thus homogeneous illumination of the exit surface.

[0020] It is possible that at least one optical component, or at least one of the optical components, incorporates a diffuser optic. A diffuser optic allows the light to be scattered appropriately.

[0021] Alternatively or additionally, at least one optical component, or at least one of the optical components, can have an array of roof prisms. This creates a BEF optic. In this context, BEF stands for "Brightness Enhancement Film." The BEF optic serves to increase the brightness of the light passing through the optical component.

[0022] Alternatively or additionally, the at least one optical component, or at least one of the optical components, may have an array of light-deflectoring prisms designed to deflect light passing through the optical component such that the mean direction of propagation of the light in front of the optical component forms an angle other than 0° with the mean direction of propagation of the light behind the optical component. The corresponding optical component thus features a so-called DTF optic. DTF stands for "Direction Turning Film." This involves a prism optic formed by linear prisms, which deflects the light by an angle in order to, for example, redirect the light back into the main direction of emission in a rotated system.The DTF optics allow the light emitted by the light sources to be deflected in such a way that it exits the lighting device in a desired principal direction parallel to the direction of travel, even when the lighting device is mounted in a rotated position. The prism angle of the light-deflectoring prisms can correspond, at least substantially, to the angle of the mounting position.

[0023] The lighting device may include a cover plate, and the lighting device is configured so that, after passing through the at least one optical component, the light at least partially exits the lighting device through the cover plate. The cover plate may be provided with a structure such as a diffuser optic. In this way, the cover plate can also contribute to light shaping, in particular to the homogenization of the light.

[0024] It is possible that a first surface of the at least one optical component, or a single optical component, is equipped with a diffuser optic, and that a second surface of the at least one optical component, or a single optical component, is equipped with an array of roof prisms. A diffuser optic can scatter the light appropriately to improve the homogeneity of the illuminated area. The BEF optic can increase the brightness of the light passing through the optical component. Together, these two surfaces or optical components can ensure efficient illumination of the light source area of ​​the lighting device.

[0025] Alternatively or additionally, a first surface of the at least one optical component, or a first optical component, may be provided with an array of roof prisms arranged side by side in a first direction and extending parallel to each other in a second direction perpendicular to the first direction. Furthermore, a second surface of the at least one optical component, or a second optical component, may be provided with an array of roof prisms arranged side by side in the second direction and extending parallel to each other in the first direction. The intersecting arrays of roof prisms improve the homogeneity of the illumination and simultaneously slightly increase the central intensity, which is advantageous for the efficient design of a signal function using such lighting systems.

[0026] Alternatively or additionally, one surface of at least one optical component or a third optical component can be equipped with an array of light-deflectoring prisms. This DTF optic allows the light emitted from the light sources to be deflected, even when the lighting device is mounted in a rotated position, so that it exits the lighting device in a desired principal direction parallel to the direction of travel.

[0027] The invention is explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 a side view of a first embodiment of a lighting device according to the invention; Fig. 2 a detailed view according to arrow II in Fig. 1; Fig. 3 a perspective detail view of a second embodiment of a lighting device according to the invention; Fig. 4 a side view of a detail of the lighting device according to Fig. 3; Fig. 5 a perspective detail view of a third embodiment of a lighting device according to the invention; Fig. 6 another perspective detail view of the lighting device according to Fig. 5; Fig. 7 another perspective detail view of the lighting device according to Fig. 5; Fig. 8 another perspective detail view of the lighting device according to Fig. 5; Fig. 9 a side view of a fourth embodiment of a lighting device according to the invention; Fig. 10 a side view of a fifth embodiment of a lighting device according to the invention with a drawn beam path of the light; Fig. 11 a side view of the lighting device according to Fig. 10; Fig. 12 a side view of a sixth embodiment of a lighting device according to the invention with a drawn beam path of the light; Fig. 13 a perspective view of a lighting device in accordance with the state of the art; Fig. 14 an exploded view of the lighting device according to Fig. 13; Fig. 15 a section through an optical component of the lighting device according to Fig. 13.

[0028] In the figures, identical or functionally equivalent parts are provided with the same reference symbols.

[0029] The lighting device shown in the figures comprises several light sources 10, an optic 11 for light capture and / or focusing, two optical components 12, 13 designed as a microstructured film and / or as a microstructured optical disc and a cover disc 14 (see Fig. 1) The lighting device is arranged so that light 15 emanating from the light sources 10 passes through the optics 11 for light detection and / or focusing, then passes through the two optical components 12, 13 and then exits the lighting device at least partially through the cover plate 14.

[0030] It is entirely possible that the lighting device does not have a cover plate 14. Furthermore, more than two optical components 12, 13 or only one optical component 12, 13 may be provided.

[0031] The light sources 10 are designed as light-emitting diodes (LEDs). In Fig. Figure 1 shows a printed circuit board 16 on which the light sources 10, designed as light-emitting diodes, are arranged. The printed circuit board 16 can, in particular, be coated with a white solder mask to reflect light that is reflected back within the system forward.

[0032] The multiple LEDs can also have different colors, for example, to implement a dual or triple function. For instance, LEDs can be arranged alternately next to each other with red and yellow, white and yellow, or white and cyan, or bi-color LEDs or RGB LEDs. The functions could include, for example, a position light, a daytime running light, and a turn signal, or a position light, a daytime running light, and an autonomous driving function, with the autonomous driving function requiring a cyan color.

[0033] The light sources 10 are arranged in a single row next to each other. Alternatively, the light sources 10 can also be arranged in two or more closely spaced rows.

[0034] The optics 11 for light detection and / or focusing have a plurality of optical areas 17 (see Fig. 3 to Fig. 8) Each of the optical areas 17 has a lens. Each of the light sources 10 is assigned to one of the optical areas 17 such that the light 15 emanating from the light source 10 passes through the assigned optical area. For this purpose, the optics 11 have an entrance surface 18 and an exit surface 19 for the light 15 emanating from the light sources 10 (see Figure 8). Fig. 4, Fig. 6 and Fig. 8).

[0035] In the embodiment according to the Fig. 3 and Fig. The optics 11, designed as a Fresnel lens, are used for light capture and / or focusing. The entrance surface 18 of the Fresnel lens is flat, while the exit surface 19 is provided with Fresnel structures to create a lens. It is also possible to arrange the Fresnel structures on the entrance surface 18 and to make the exit surface 19 flat.

[0036] A structure not shown, in particular a structure serving as a diffuser, may be provided on the flat surface of the Fresnel optic. It is entirely possible to provide a structure, in particular a structure serving as a diffuser, on the surface with the Fresnel structures, either alternatively or additionally.

[0037] In the embodiment according to the Fig. 5 to Fig. The optics 11, designed as a TIR optic, are used for light acquisition and / or focusing. The entrance surface 18 and the exit surface 19 are curved to form a lens. It is possible to design one of the two surfaces, particularly the exit surface 19, to be flat. A structure not shown, particularly one serving as a diffuser optic, may be provided on the entrance surface 18 and / or the exit surface 19.

[0038] The first optical component 12 of the embodiment according to Fig. 1 and Fig. 2 features a diffuser optic. This diffuser optic can be arranged on the inlet surface and / or on the outlet surface of the first optical component 12.

[0039] The second optical component 13 of the embodiment according to Fig. 1 and Fig. 2 features a BEF optic. Fig. Figure 2 shows an array 20 of roof prisms 21 forming the BEF optics, which is arranged on the exit surface of the second optical component 13. It is also possible to arrange a BEF optics on the entrance surface of the second optical component 13, either alternatively or additionally. In particular, it is possible to arrange the arrays 20 of roof prisms 21 on the entrance surface and on the exit surface of the second optical component 13 so that the ridge lines of the roof prisms 21 on the entrance surface extend in a first direction and the ridge lines of the roof prisms 21 on the exit surface extend in a second direction, which is perpendicular to the first direction.

[0040] The second optical component 13 of the embodiment according to the Fig. 10 and Fig. 11 features DTF optics. Fig. Figure 11 shows an array 22 of light-deflectoring prisms 23 forming the DTF optics, which is arranged on the exit surface of the second optical component 13. The prisms 23 are configured to deflect light passing through the second optical component 13 such that the mean direction of propagation of the light in front of the optical component forms an angle with the mean direction of propagation of the light behind the optical component. In the illustrated embodiment, the angle is approximately 30° (see Figure 11). Fig. 10 and Fig. 11). The angle can also have other sizes.

[0041] It is entirely possible to arrange a DTF optic on the entrance surface of the second optical component 13, either alternatively or additionally. Furthermore, it is possible to provide an array 22 of light-deflectoring prisms 23 on both the first optical component 12 and the second optical component 13, which serves as a DTF optic (see Fig. 14).

[0042] It is still possible to provide the cover plate 14 with a structure such as a diffuser look.

[0043] The lighting device can have different variations of optical components or functional structures. Some examples are given below. - A diffuser optic, followed by a horizontally oriented BEF optic, followed by a vertically oriented BEF optic. - A diffuser optic, followed by a horizontally oriented BEF optic, followed by a vertically oriented BEF optic, followed by a cover plate with or without structuring. - A horizontally oriented BEF optic followed by a vertically oriented BEF optic. - A horizontally oriented BEF optic, followed by a vertically oriented BEF optic, followed by a cover plate with or without structuring. - A diffuser optic, followed by a horizontally oriented BEF optic, followed by a DTF optic. - A diffuser optic, followed by a BEF optic with horizontal orientation, followed by a DTF optic, followed by a cover plate with or without structuring.

[0044] This list is merely exemplary and should not be considered exhaustive. Further combinations of optical components or functional structuring of the lighting device are certainly possible. Reference symbol list 1 light source 2 cases 2a, 2b Housing part 3 fiber optic cables 4 reflective foil 5a, 5b optical component designed as a micro-optical film 6 Cover plate 7 Roof prism of the optical component 5b 10 light sources 11 Optics for light capture and / or focusing 12 first optical component 13 second optical component 14 Cover plate 15 Light emanating from the light source 16 circuit board 17 Optical area of ​​the optics for light detection and / or focusing 18 Entrance area of ​​the optics for light capture and / or focusing 19 Exit surface of the optics for light capture and / or focusing 20 array of roof prisms 21 Roof prism 22 Array of light-deflecting prisms 23 light-reflecting prism α Roof angle of the roof primate QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 10 2021 122 264 A1

[0006] DE 10 2022 113 052 A1

[0009]

Claims

[1] Lighting device for a motor vehicle, comprising - a plurality of light sources (10), - at least one optical component (12, 13) designed as a microstructured film and / or as a microstructured optical disk, as well as - an optic (11) for light detection and / or focusing, wherein the lighting device is arranged so that light (15) emanating from the light sources (10) passes through the optic (11) for light detection and / or focusing before passing through the at least one optical component (12, 13). [2] Lighting device according to claim 1, characterized by , that the optics (11) for light capture and / or focusing are Fresnel optics. [3] Lighting device according to claim 2, characterized by, that the Fresnel optics has an inlet surface (18) and an outlet surface (19) for the light (15) emanating from the light sources (10), wherein the inlet surface (18) and / or the outlet surface (19) of the Fresnel optics is provided with a structuring, in particular with a diffuser optics. [4] Lighting device according to claim 1, characterized by that the optics (11) for light detection and / or focusing are TIR optics. [5] Lighting device according to claim 4, characterized by , that the TIR optics has an inlet surface (18) and an outlet surface (19) for the light (15) emanating from the light sources (10), wherein the inlet surface (18) and / or the outlet surface (19) of the TIR optics is provided with a structuring, in particular with a diffuser optics. [6] Lighting device according to any one of claims 1 to 5, characterized by, that the optics (11) for light detection and / or focusing has a plurality of optical areas (17), wherein each of the light sources (10) is assigned one of the optical areas (17) such that the light (15) emanating from the light source (10) passes through the assigned optical area (17). [7] Lighting device according to any one of claims 1 to 6, characterized by , that the illumination device comprises several optical components (12, 13) which are designed as a microstructured film and / or as a microstructured optical disk, wherein the illumination device is arranged such that the light (15) emerging from the optics (11) for light detection and / or focusing passes through the majority of the optical components (12, 13) successively. [8] Lighting device according to any one of claims 1 to 7, characterized by, that the at least one optical component (12, 13) or at least one of the optical components (12, 13) has a diffuser optic. [9] Lighting device according to any one of claims 1 to 8, characterized by , 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] Lighting device according to any one of claims 1 to 9, characterized by , 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-deflectoring prisms (23) which are configured to deflect light (15) passing through the optical component (12, 13) such that the mean direction of propagation of the light (15) in front of the optical component (12, 13) forms an angle other than 0° with the mean direction of propagation of the light (15) behind the optical component (12, 13). [11] Lighting device according to any one of claims 1 to 10, characterized by , that the lighting device comprises a cover plate (14), wherein the lighting device is arranged so that the light, after passing through the at least one optical component (12, 13), exits the lighting device at least partially through the cover plate (14). [12] Lighting device according to claim 11, characterized by , that the cover disc (14) is provided with a structure such as a diffuser optic. [13] Lighting device according to any one of claims 1 to 12, characterized by, that a first surface of the at least one optical component (12, 13) or a first optical component (12, 13) is provided with an array (20) of roof prisms (21) which are arranged next to each other in a first direction and extend parallel to each other in a second direction perpendicular to the first direction, and that a second surface of the at least one optical component (12, 13) or a second optical component (12, 13) is provided with an array (20) of roof prisms (21) which are arranged next to each other in the second direction and extend parallel to each other in the first direction. [14] Lighting device according to any one of claims 1 to 13, characterized by, that a first surface of the at least one optical component (12, 13) or a first optical component (12, 13) is provided with a diffuser optic and that a second surface of the at least one optical component (12, 13) or a second optical component (12, 13) is provided with an array (20) of roof prisms (21). [15] Lighting device according to one of claims 13 or 14, characterized by , that a surface of the at least one optical component (12, 13) or a third optical component (12, 13) is provided with an array (22) of light-deflectoring prisms (23).

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