Lighting device for backlighting an at least translucent panel, associated arrangement and associated use

Abstract

The invention relates to a lighting device (1) for backlighting an at least translucent panel (2) of a motor vehicle, comprising: a housing (3) which forms a cavity (11) with an opening (12), said opening facing a rear side (R) of the panel (2) when the lighting device (1) is mounted as intended; a film layer structure (4) which closes the opening (12) and delimits the cavity (11) and an inner main surface (I) of which faces the cavity (11) and an outer main surface (O) of which faces, in the case of mounting as intended, the rear side (2r) of the panel (2); wherein the film layer structure (4) is designed such that the film layer structure (4) is opaque over the outer main surface (O) except for a light-transmissive lighting region (4b) which, when the lighting device (1) is mounted as intended, is arranged for backlighting the panel (2); a light source (6) arranged in the cavity (11), for transilluminating the film layer structure (4); a light guide (5) arranged in the cavity (11), for guiding light from the light source (6) to the lighting region (4b). The invention also relates to an associated arrangement (10) and to an associated use.

Description

[0001] Lighting device for backlighting an at least translucent aperture, associated arrangement and associated use

[0002] The invention relates to a lighting device for backlighting an at least translucent panel, an associated arrangement, and its use. Typically, the interior of the passenger compartment is lined with one or more decorative panels. Increasingly, this area is also used for visual displays, for example, to place indicators that are only visible to the driver when the light source is activated, thus avoiding overwhelming or distracting the driver with information. When the light source is switched off, the indicator is not visible and disappears behind the panel's decorative trim. It has also become common practice, for aesthetic reasons or for better orientation in the darkened passenger compartment, to provide additional lighting that only partially illuminates the decorative trim, also known as ambient lighting.The design trend is moving towards increasingly larger, seamless panels, where the visible surface facing the passenger compartment is only partially backlit. For example, the panel might cover a large portion of a vehicle door or dashboard with a translucent decorative layer, such as a textile or wood grain pattern, with only a small portion of the visible surface backlit as a narrow line. It is known to position light sources behind the decorative layer of a panel in such a way that the light from these sources backlit the decorative layer in a limited area or even passed through it in a limited area. However, this carries the risk of light unintentionally escaping the panel at undesired points, which would detract from the overall visual appearance.Previously, these problems were solved by using two-component (2K) plastic parts as housings for the lighting devices, employing an opaque material for the housing and a transparent or translucent material for the viewing windows within the housing. However, housings for such lighting devices manufactured using 2K injection molding are particularly disadvantageous with relatively large bezels, as the 2K housing is not easily deformable and, due to production tolerances, does not fit snugly against the bezel along its entire length. Furthermore, a special mold must be manufactured for such a 2K housing. Modifying this mold, if at all possible, is complex and costly, meaning that a new mold generally has to be created for each new variant of a lighting device. Such design changes, however, occur frequently during facelifts of vehicle models.

[0003] Against this background, there was a need for a solution for a generic lighting device which, in addition to aesthetically pleasing backlighting of an at least translucent aperture that avoids stray light, offers improved adaptability of the lighting device to design changes, is particularly easy to install, and is designed to save installation space. This objective is achieved by a lighting device according to claim 1. An equally advantageous arrangement and use are each the subject of the respective dependent claim. Advantageous embodiments are each the subject of the dependent claims. It should be noted that the features listed individually in the claims can be combined with one another in any technologically meaningful way and demonstrate further embodiments of the invention.The description, especially in connection with the figures, further characterizes and specifies the invention.

[0004] The invention relates to a lighting device for backlighting a motor vehicle's panel that is at least partially, and preferably over its entire extent, translucent. Translucency over the entire extent does not necessarily imply that the transmittance is uniform over the entire extent. For example, a decorative layer can be part of the panel, the transmittance of which varies locally due to the decoration, which is visible to an observer when the panel is properly installed. The decorative layer is created, for example, by a printed layer. For example, the panel is made of at least one thermoplastic. Preferably, the panel has no locally varying material composition along 90 percent of its maximum extent, and more preferably along its entire maximum extent.For example, the aperture is produced by injection molding or 2K injection molding, or by back- or front-injection of a film belonging to the aperture with a thermoplastic.

[0005] The lighting device according to the invention comprises a housing which forms a cavity with an opening that, when the lighting device is installed as intended, faces the rear side of the aperture. The housing is, for example, shell-shaped. The housing is, for example, made of a thermoplastic using an injection molding process. The housing is either a single piece or made of multiple parts.

[0006] The lighting device according to the invention further comprises a foil layer structure that closes the opening and defines the cavity, the inner main surface of which faces the cavity and the outer main surface of which, when the aperture is properly installed, faces the rear of the aperture. The main surfaces are understood to be those surfaces with the largest area, which adjoin each other at their outer circumference via comparatively narrow end faces.

[0007] According to the invention, the film layer structure is designed such that, with the exception of a translucent illuminating area arranged when the lighting device is installed as intended for backlighting the aperture, the film layer structure is opaque across its outer main surface. In other words, the film layer structure is translucent or transparent in an illuminating area at least across its outer main surface and opaque in an area of ​​the outer main surface lying outside the illuminating area, for example, due to the use of an opaque material for a coating applied to the film layer structure in certain areas. The coating allows the illuminating area to be easily adapted to any design requirements. The multiple illuminating areas do not necessarily have to be related.

[0008] According to the invention, a light source arranged in the cavity is provided for illuminating the film layer structure, such as a light-emitting diode.

[0009] According to the invention, a light guide is further provided in the cavity to direct light from the light source to at least one illuminated area. Preferably, the shortest distance between the light source and the illuminated area is at least 5 cm, preferably more than 10 cm.

[0010] The lighting device according to the invention enables an aesthetically sophisticated backlighting of an at least translucent aperture, avoiding stray light, and allows for improved adaptability of the lighting device to design changes through comparatively simple modification of the film layer structure.

[0011] Preferably, the film layer structure has a maximum thickness of less than 0.8 mm, preferably less than 0.5 mm, in order to reduce light emission at the end faces of the film layer structure.

[0012] Preferably, the foil layer structure is bonded to the housing by a material bond, for example by thermal welding, in particular ultrasonic welding. More preferably, the foil layer structure is bonded to the housing by a material bond all around the opening.

[0013] Preferably, the film layer structure comprises at least one translucent or transparent film and an opaque masking layer outside the at least one illuminating area. For example, the masking layer defines an illuminating area in the form of an outline of a symbol. Furthermore, a translucent coating covering the illuminating area, applied, for example, by printing, can be provided. For example, a symbol, such as a pictogram, or a pattern is applied to the illuminating area as a printed coating. Alternatively, a light-diffusing, and thus homogenizing, translucent coating can be provided. In one embodiment, the masking layer forms an opaque island enclosed by the illuminating area. By printing on the transparent film, the film layer structure and thus the optical appearance of the illuminating area can be adapted to any design specifications.

[0014] Preferably, the light guide has a maximum extent in a direction parallel to the inner main surface of the foil layer structure.

[0015] Preferably, the housing forms a seat that surrounds the end faces of the film layer structure. For example, the seat is formed by a projection of the housing that surrounds the film layer structure.

[0016] Preferably, the light source is oriented such that its main direction of propagation is essentially parallel to the inner main surface of the film layer structure. For example, the light is coupled into the light guide via a light coupling surface located on a lateral end face of the light guide. This light coupling surface forms, for example, a right angle with the inner main surface of the film layer structure.

[0017] In order to achieve a more uniform illumination of the illuminating area, the light guide and / or the film layer structure, according to a preferred embodiment, has a light-diffusing layer, for example by coating the film of the film layer structure.

[0018] Preferably, the light guide is manufactured using a 2K injection molding process, whereby, for example, a light-diffusing layer made of diffusely colored thermoplastic material is embedded in a layer of transparent thermoplastic, together forming the light guide. Preferably, the light-diffusing layer forms a light-emitting surface of the light guide opposite the illuminating area.

[0019] According to a preferred embodiment, the housing has webs or ribs that extend through correspondingly arranged openings in the foil layer structure for light blocking.

[0020] The invention relates to an arrangement comprising an at least translucent aperture and a lighting device in one of the previously described embodiments, wherein the opening of the housing and the outer main surface of the film layer structure of the aperture are facing the aperture.

[0021] According to a preferred embodiment of the arrangement according to the invention, the contour of the outer main surface is adapted to a shape of the back of the aperture.

[0022] According to a further preferred embodiment of the arrangement according to the invention, the housing is fixed to the aperture, wherein the outer main surface is spaced apart from the rear of the aperture and / or loosely rests against the rear.

[0023] According to yet another preferred embodiment of the arrangement according to the invention, a first total area measure of the outer main surface constitutes a fraction, preferably less than V2, of a second total area measure of the back of the aperture.

[0024] The invention further relates to the use of the lighting device in a motor vehicle.

[0025] The invention is explained in more detail with reference to the following figures. These figures are to be understood as examples only and represent merely one preferred embodiment. They show:

[0026] Fig. 1 is a perspective view to illustrate the use of the lighting device 1 or arrangement 10 according to the invention;

[0027] Fig. 2 shows a sectional view of a first embodiment of the lighting device 1 or arrangement 10 according to the invention;

[0028] Fig. 3 shows a sectional view of a second embodiment of the lighting device 1 or arrangement 10 according to the invention;

[0029] Fig. 4 shows a top view of the outer main surface 0 of the film layer structure 4 of the lighting device 1 according to the invention of figures 2 and 3.

[0030] Figure 1 schematically shows the inventive use of the arrangement 10, consisting of aperture 2 and lighting device 1, in a passenger compartment of a motor vehicle, wherein the lighting device 1, which is not visible in the illustrated view, is covered by the aperture 2. As shown here, the arrangement 10 according to the invention is integrated into the door trim, the dashboard, and / or the trim of the center console. The at least translucent aperture 2 covers the invisible lighting device 1 in order to create a luminous area 9 by backlighting it, which constitutes only a small fraction of the total area of ​​the visible surface, i.e., the viewing area of ​​the aperture 2 facing the occupant of the passenger compartment. Figure 2 shows a cross-sectional view of a first embodiment of the lighting device 1.The arrangement consists of a first lighting device 1 and an aperture 2, wherein the aperture 2 is translucent at least in certain areas, preferably over its entire extent. Translucency over the entire extent does not necessarily imply that the transmittance is uniform over the entire extent of the aperture 2. For example, a decorative layer can be part of the aperture 2, the transmittance of which varies locally due to the decoration shown, which is visible to an observer when the aperture 2 is installed as intended. The decorative layer, not shown in detail here, is created, for example, by a printed layer or is a surface embossing of the aperture 2. Here, the aperture 2 is made of a thermoplastic and does not have a locally varying material composition along its entire maximum extent.For example, aperture 2 is produced by injection molding or 2K injection molding, or by back- or front-injection of a film belonging to the aperture with a thermoplastic.

[0031] The lighting device 1 according to the invention, arranged on the rear side R of the aperture 2, has a shell-shaped housing 3 which forms a cavity 11 with an opening 12. The opening 12 faces the rear side of the aperture. The housing 3 is, for example, made of a thermoplastic using an injection molding process. The housing 3 can be made in one piece or in multiple parts.

[0032] The lighting device 1 according to the invention further comprises a foil layer structure 4 that closes the opening 12 and delimits the cavity 11, the inner main surface I of which faces the cavity 11 and the outer main surface 0 of which faces the rear side R of the aperture 2. The main surfaces (inner main surface I and outer main surface 0) are understood to be those surfaces with the largest area, which adjoin each other at their outer circumference via comparatively narrow end faces.

[0033] According to the invention, the film layer structure 4 is designed such that, with the exception of at least one illuminating area 4b arranged for backlighting the aperture 2 when the lighting device 1 is installed as intended, the film layer structure 4 is opaque. If several illuminating areas 4b are provided, they need not necessarily be contiguous. The film layer structure 4 has a maximum thickness of less than 0.8 mm, preferably less than 0.5 mm, in order to reduce light emission at the end faces of the film layer structure 4.In other words, the film layer structure 4 is translucent or transparent at least over the outer main surface 0 in a luminous area 4b and opaque in an area of ​​the outer main surface 0 lying outside the luminous area 4b, for example due to an opaque material choice or a coating of the film layer structure 4 that is only applied in certain areas. Thus, the film layer structure 4 shown has a translucent or transparent film 4c and, outside the at least one luminous area 4b, an opaque film 4a masking layer on the film 4c, more precisely on the side of the film 4c facing the aperture 2.

[0034] The housing 3 forms a seat 3a enclosing the end faces of the foil layer structure 4, wherein the seat 3a is defined by a foil layer structure

[0035] 4. The housing 3 is formed as a surrounding projection. Furthermore, the foil layer structure 4 is connected to the housing 3 around the opening 12 in a material-bonded manner, for example by thermal welding, in particular ultrasonic welding.

[0036] According to the invention, a light source 6, such as a light-emitting diode, is also provided in the cavity 11, which is mounted on a circuit board 7 and electrically contacted via a plug connection 8 for illuminating the foil layer structure 4.

[0037] According to the invention, a light guide 5 is further provided in the cavity to guide light from the light source 6 to at least one illuminating area 4b. Preferably, the shortest distance between the light source 6 and the illuminating area 4b is at least 5 cm, preferably more than 10 cm. The light guide 5 has a maximum extension in a direction parallel to the inner main surface I of the film layer structure 4. The light source 6 is oriented such that its main direction of propagation is substantially parallel to the inner main surface I of the film layer structure 4, and the light enters the light guide 5 via a light coupling surface.

[0038] Light is coupled to the light guide 5 at a lateral end face. This light coupling surface forms, for example, a right angle with the inner main surface I of the film layer structure 4. To achieve more uniform illumination of the lighting area 4b, the film layer structure 4 in the first embodiment, shown in Figure 2, has a light-diffusing coating, while in the second embodiment, shown in Figure 3, the light guide 5, manufactured by 2K injection molding, has a light-diffusing layer 5a. The first and second embodiments also have in common that, at the latest after final assembly, the lighting device 1 is fixed to the aperture 2, but the outer main surface 0 is spaced apart from the rear surface R of the aperture 2 and / or loosely rests against the rear surface R of the aperture 2.

[0039] The lighting device 1 according to the invention enables aesthetically sophisticated backlighting of an at least translucent aperture 2, avoiding stray light. Furthermore, the lighting device 1 offers improved adaptability to design changes through comparatively simple modifications to the film layer structure 4. Figure 4 shows a top view of the outer main surface 0 of the film layer structure 4. The linear, loop-shaped illuminating area 4b is bounded by an opaque masking layer 4b. As a design feature, the loop-shaped illuminating area 4b, defined by the masking layer 4b, surrounds an opaque island. As shown by way of example, the illuminating area 4b can also have a symbol or pattern printed on it, as shown in area 4d, or a light-diffusing, and thus homogenizing, translucent print can be provided, as is the case in area 4c.

Claims

Claims 1. Lighting device (1) for backlighting an at least translucent panel (2) of a motor vehicle, comprising: a housing (3) which forms a cavity (11) with an opening (12) facing a rear side (R) of the panel (2) when the lighting device (1) is installed as intended; a foil layer structure (4) closing the opening (12) and defining the cavity (11), the inner main surface (I) of which faces the cavity (11) and the outer main surface (0) of which faces the rear side (2r) of the panel (2) when the lighting device (1) is installed as intended; wherein the foil layer structure (4) is designed such that the foil layer structure (4) is opaque over its outer main surface (0) except for a light-transmitting illuminating area (4b) arranged when the lighting device (1) is installed as intended for backlighting the panel (2);a light source (6) arranged in the cavity (11) for illuminating the film layer structure (4); a light guide (5) arranged in the cavity (11) to direct light from the light source (6) to the illuminating area (4b).

2. Lighting device (1) according to claim 1, wherein the film layer structure (4) has a maximum thickness of less than 0.8 mm, preferably less than 0.5 mm.

3. Lighting device (1) according to one of the preceding claims, wherein the film layer structure (4) is materially bonded to the housing (3).

4. Lighting device (1) according to one of the preceding claims, wherein the film layer structure (4) comprises at least one translucent or transparent film (4c) and an opaque masking layer (4a) outside the lighting area (4b).

5. Lighting device (1) according to one of the preceding claims, wherein the light guide (5) has a maximum extent in a direction parallel to the inner main surface (I) of the foil layer structure (4).

6. Lighting device (1) according to one of the preceding claims, wherein the housing (3) forms a seat (3a) enclosing the end faces of the film layer structure (4).

7. Lighting device (1) according to one of the preceding claims, wherein the main propagation direction of the light source (6) is substantially parallel to the inner main surface (I) of the film layer structure (4).

8. Lighting device (1) according to one of the preceding claims, wherein the light guide (5) and / or the film layer structure (4) comprise a light-diffusing layer (5a).

9. Lighting device (1) according to one of the preceding claims, wherein the light guide (5) is manufactured using the 2K injection molding process.

10. Lighting device (1) according to one of the preceding claims, wherein the housing (3) forms webs or ribs which extend through correspondingly arranged openings in the foil layer structure (4) for light blocking.

11. Arrangement (10) comprising an at least translucent aperture (2) and a lighting device (1) according to one of the preceding claims, wherein the opening (12) of the housing (3) and the outer main surface (0) of the film layer structure (4) are facing the aperture (2).

12. Arrangement (10) according to the preceding claim, wherein a contour of the outer main surface (O) is adapted to a shape of the rear side (R) of the aperture (2).

13. Arrangement (10) according to one of the two preceding claims, wherein the housing (3) is fixed to the aperture (2), wherein the outer main surface (0) is spaced apart from the rear (R) of the aperture (2) or loosely rests against the rear (R).

14. Arrangement (10) according to any one of the preceding claims 11 to 13, wherein a first total area measure of the outer main surface (0) is a fraction, preferably less than V2, of a second total area measure of the rear side (R) of the aperture (2).

15. Use of the lighting device (1) according to any one of the preceding claims 1 to 10 in a motor vehicle.

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