Lightng device for vehicle

Abstract

A lighting device (100; 200; 310), in particular for use as an exterior vehicle light, comprises at least one light emitting element (110; 210) and a light deflecting member (130; 230), the light deflecting member (130; 230) comprising an in-coupling surface (132; 232) arranged for receiving light (LE) which has been emitted by the light emitting element (110; 210), at least one light deflecting structure (140; 240) for deflecting light (LI) which has been in-coupled to the light deflecting member (130; 230) via the in-coupling surface (132; 232), and an out-coupling surface (134; 234) arranged for out-coupling, towards an environment of the lighting device (100; 200; 310), light (LO) which has been in-coupled to the light deflecting member (130; 230) via the in-coupling surface (132; 232) and deflected by means of the light deflecting structure (140; 240). The lighting device (100; 200; 310) further comprises an opaque cover portion (160; 260) covering the at least one light emitting element (110; 210) at least partially with respect to the environment of the lighting device (100; 200; 310). The at least one light emitting element (110; 210) is arranged on an inward surface of the opaque cover portion (160; 260).

Description

[0001] The present disclosure relates to a lighting device, in particular for use as an exterior vehicle light, as well as to a vehicle comprising a lighting device.Background

[0002] Apart from an efficient production of light, compactness, durability, and aesthetics are among the primary criteria in the development of lighting devices. This applies especially in connection with vehicle lighting, but also in the fields of electrical household equipment, electrical lifestyle appliances, including wearable electrical devices, etc.

[0003] There is a continuous need for improved lighting techniques.Details of invention

[0004] The problem is solved by a lighting device according to claim 1 and by a vehicle according to claim 15.

[0005] According to an aspect, a lighting device, in particular for use as an exterior vehicle light, is provided. The lighting device comprises at least one light emitting element. The lighting device further comprises a light deflecting member comprising an in-coupling surface arranged for receiving light which has been emitted by the light emitting element, at least one light deflecting structure for deflecting light which has been in-coupled to the light deflecting member via the in-coupling surface, and an out-coupling surface arranged for out-coupling, towards an environment of the lighting device, light which has been in-coupled to the light deflecting member via the in-coupling surface and deflected by means of the light deflecting structure. The lighting device further comprises an opaque cover portion covering the at least one light emitting element at least partially with respect to the environment of the lighting device. The at least one light emitting element is arranged on an inward surface of the opaque cover portion.

[0006] By the provided lighting device, a compact, in particular flat, implementation of the lighting device combined with an efficient production of light is enabled. This is achieved by enabling that the at least one light emitting element and the light deflecting member are arranged, at least essentially, in a same extension plane of the lighting device, wherein the extension plane may further correspond, e.g. be parallel, to an out-coupling surface for the produced light.

[0007] Furthermore, a housing-free implementation of the lighting device is enabled. This is achieved by the at least one light emitting element being arranged on an inward surface of the opaque cover portion. A heat transfer from the at least one light emitting element towards an environment of the lighting device may be enabled through the opaque cover portion, thus dispensing with a ventilated housing. This further facilitates a compact, in particular flat, implementation of the lighting device. Moreover, with or without a housing of the lighting device, the above also facilitates an extended application range of the lighting device, in particular in appliances which are both heat-sensitive and space-critical.

[0008] Furthermore, improved aesthetics are facilitated by the provided lighting device. This is achieved by the at least one light emitting element being covered with respect to the environment. Especially, light emitting elements which are visible in a non-operational state of a lighting device are perceived by many users as aesthetically disadvantageous in comparison to a concealed arrangement of the light emitting elements. Moreover, by means of the light deflecting member it is enabled that a background of the light deflecting member which may be visible to the environment through the light deflecting member may be designed arbitrarily without significantly affecting a lighting functionality of the lighting device. Thus, when the lighting device is mounted on a vehicle or on another appliance, an entire exterior appearance of the lighting device, including the visible opaque cover portion and a visible background of the light deflecting member, can be designed, e.g., colored, arbitrarily without significantly affecting a lighting functionality of the lighting device.

[0009] Furthermore, by the at least one light emitting element being covered with respect to the environment by means of the opaque cover portion, hot spots in a distribution of the out-coupled light due to visible light emitting elements can be avoided. An improved homogeneity of a light distribution of the lighting device is thus facilitated.

[0010] The opaque cover portion may comprise heat conductive material, in particular heat conductive plastic material and / or a heat conductive resin composition. Using heat conductive plastic or resin material for at least a portion of the opaque cover portion facilitates an integral forming of at least the portion of the opaque cover portion with at least a portion of the light deflecting member, e.g., in a two-step, or a multi-step, injection molding process.

[0011] The opaque cover portion may be integrally formed with at least a portion of the light deflecting member. An improved stability, weather-proofness, homogenous appearance, and efficient production of the lighting device are facilitated in this way.

[0012] The lighting device may further comprise at least one printed circuit arrangement for operating the at least one light emitting element, the at least one printed circuit arrangement arranged on the inward surface of the opaque cover portion. The at least one printed circuit arrangement can be at least partially printed onto the inward surface of the opaque cover portion, in particular, in the absence of an additional substrate of the printed circuit arrangement. In this way, a compact implementation of the lighting device and / or a heat transfer from the light emitting element through the opaque cover portion are further facilitated.

[0013] The at least one light emitting element may comprise at least one light emitting diode, LED.

[0014] The light deflecting member may be configured to function as a light guide for guiding light which has been in-coupled to the light deflecting member via the in-coupling surface towards the light deflecting structure. The in-coupling surface may correspond to a side surface of the light deflecting member and the out-coupling surface corresponds to an outward surface of the light deflecting member.

[0015] The light deflecting member may have an at least essentially planar shape, in particular an at least essentially curved or flat planar shape, in at least a region of the light deflecting member, said region including the in-coupling surface, the light deflecting structure and the out-coupling surface.

[0016] The light deflecting member may be configured to refract light which has been deflected by means of the light deflecting structure, in particular to function as an output lens of the at least one lighting device.

[0017] The light deflecting member may be integrally formed in at least a region of the light deflecting member, said region including the in-coupling surface and the out-coupling surface.

[0018] The light deflecting member may constitute an exterior surface of the lighting device.

[0019] The at least one light deflecting structure may be arranged at an inward surface of the light deflecting member.

[0020] The at least one light deflecting structure may comprise at least one of a surface structure or an optical microstructure.

[0021] The lighting device may further comprise a housing which accommodates the at least one light emitting element, the printed circuit arrangement and / or the light deflecting member.

[0022] The lighting device may be configured to function as at least one of a back light, a stop light and / or an indicator light of a vehicle.

[0023] According to another aspect, a vehicle is provided. The vehicle comprises a lighting device as provided herein.Description of the Figures

[0024] Further details, objects and advantages of the invention become clear from the detailed description and the drawings. There is shown in: Fig. 1a lighting device according to an example; Figs. 2A - 2Ddifferent views of a lighting device according to another example; and Fig. 3a vehicle according to an example. Examples

[0025] Fig. 1 shows schematically and exemplarily a lighting device 100, for example, for use as an exterior vehicle light. The lighting device 100 comprises a light emitting element 110, such as a light emitting diode, LED. The lighting device 100 further comprises a light deflecting member 130 and an opaque cover portion 160. The opaque cover portion 160 covers the light emitting element 110 mechanically and visually with respect to an environment of the lighting device 100. The light deflecting member 130 is made at least partially of material which is transparent to light emitted by the light emitting element 110.

[0026] In the shown example, the lighting device 100 further comprises a printed circuit arrangement 120, which is arranged on an inward surface of the opaque cover portion 160. The printed circuit arrangement 120 serves for operating the light emitting element 110. In the shown example, the printed circuit arrangement 120 is at least partially printed on a substrate. On the substrate, the light emitting element 110 is also arranged. In the shown example, the lighting device 100 further comprises a housing 170 which accommodates the light emitting element 110, the printed circuit arrangement 120, and the light deflecting member 130.

[0027] The light deflecting member 130 is arranged adjacent the light emitting element 110 to receive light which has been produced by the light emitting element 110. An in-coupling surface 132 of the light deflecting member 130 is arranged to face the light emitting element 110. Light which has been emitted by the light emitting element 110 and which is received at the light deflecting member 130 is in-coupled to the light deflecting member 130 via the in-coupling surface 132.

[0028] The light deflecting member 130 is configured to function as a light guide for light LI which has been in-coupled through the in-coupling surface 132. The in-coupled light LI is guided, for example, by internal reflection, in the light deflecting member 130 towards a light deflecting structure 140 of the light deflecting member 130. The light deflecting structure 140 is adapted to deflect the impinging light LI, which has been guided in the light deflecting member 130, to cause out-coupling of the deflected light L0 through an out-coupling surface 134 of the light deflecting member 130 towards an environment of the lighting device 100.

[0029] To cause out-coupling of light via the out-coupling surface 134, the light deflecting structure 140 is configured in some examples to deflect the impinging light LI in such way that a reflection angle of the deflected light LO differs from an impinging angle, especially, such that the reflection angle with respect to a surface normal of the out-coupling surface 134 is smaller than the impinging angle with respect to the surface normal of the out-coupling surface 134. In that way, a transmission rate of the deflected light LO, i.e., after deflection by the light deflecting structure 140, at the out-coupling surface 134 is increased relative to a transmission rate associated with internal reflection of the guided light LI in the light deflecting member 130 prior to deflection by the light deflecting structure 140. For this purpose, in some examples, the light deflecting structure 140 comprises an optical microstructure which is embedded in, or applied to, an inward surface 136 of the light deflecting member 130. In other examples, the light deflecting structure 140 comprises a surface roughness of the inward surface 136 of the light deflecting member 130, wherein the surface roughness has been selected such that it is suited for straying the impinging light LI. In some examples, a surface roughness is combined with a mirror element, such as a mirror foil, which extends along the inward surface 136 of the light deflecting member 130 to reflect light which has been strayed by the surface roughness towards the interior of the lighting device 100.

[0030] As shown schematically in Fig. 1, the light deflecting structure 140 is configured in some examples to cause partial deflection and out-coupling of the impinging light LI at any of multiple regions of the light deflecting structure 140 over an extended length of the light deflecting structure 140, wherein the multiple regions are arranged along the main direction of propagation of the guided light LI in the light deflecting member 130. In this way, an out-coupling of deflected light LO over an extended length, for example on an extended area, of the out-coupling surface 134 is achieved.

[0031] An area of the lighting device 100 on which light LO is out-coupled towards the environment as well as a distribution of the out-coupled light LO, for example, an angular intensity distribution of the out-coupled light LO, can be controlled, by adapting the light deflecting structure 140 accordingly. Furthermore, a desired distribution of the out-coupled light LO is in some examples partially achieved by configuring a shape and / or an optical density distribution of the light deflecting member 130, for example, a shape of the out-coupling surface 134. In this way, the light deflecting member 130 additionally constitutes a (conventional) optical lens for the deflected light LO, for example, at the instance of out-coupling.

[0032] The opaque cover portion 160 comprises, in some examples, heat conductive material. For example, the opaque cover portion 160 can be made of a heat conductive resin composition and / or heat conductive plastic material. Thus, the opaque cover portion 160 provides for efficient transfer of heat generated by the light emitting element 110 through the opaque cover portion 160 to the environment of the lighting device 100. A heat transfer from the light emitting element 110 to an environment of the lighting device 100 is further improved by the arrangement of the light emitting element 110 in a proximity, for example, attached to, the inside of the opaque cover portion 160. A ventilation of an interior of the lighting device 100 to avoid overheating of the interior of the lighting device 100 can thus be dispensed with in some examples. Moreover, efficient transfer of heat from the light emitting element 110 to an environment through the opaque cover portion 160 allows for a wide application range of the lighting device 100, for example, when mounted on heat sensitive appliances.

[0033] In some examples of the lighting device 100, a housing 170 is dispensed with. Dispensing with a housing 170 improves compactness of the lighting device 100. Furthermore, dispensing with a housing 170 allows for a mounting of the lighting device 100 on a surface of a vehicle or another appliance, wherein a finished surface of the vehicle or the other appliance remains visible through the light deflecting member 130. This allows for various designs, including a barely visible arrangement of the lighting device 100 when in a switched-off state.

[0034] Dispensing with a housing 170 is enabled in some examples by an efficient transfer of heat from the light emitting element 110 to an environment through the opaque cover portion 160. Efficient heat transfer through the opaque cover portion 160, as described above, makes a provision of a housing 170 for ventilation purposes dispensable. It allows, in some examples, a mounting of the lighting device 100 without a housing 170 even on heat sensitive appliances.

[0035] In some examples, the opaque cover portion 160 and at least a portion of the light deflecting member 130 are formed integrally, for example, by a same injection molding process. To obtain transparency of the light deflecting member 130 and opacity of the opaque cover portion 160 when forming these contours integrally, a two-step, or multi-step, injection molding process is used in some examples.

[0036] In the shown example, the lighting device 100 has essentially the shape of a curved plane. In this case, for example, the lighting device 100 is configured to become mounted on, for example, integrated in, a curved surface of a vehicle or another appliance. An essentially planar configuration of the lighting device 100 provides for a compact implementation of the lighting device 100 while also providing an extended area on which out-coupled light LO is emitted. In other examples, the lighting device 100 may have any different shape.

[0037] A compact implementation of the lighting device 100, especially an essentially (curved or flat) planar shape, is facilitated by an arrangement of the light emitting element 110 essentially in an extension plane of the light deflecting member 130. In this way, it is enabled to reduce a thickness of the lighting device 100. Reducing a thickness of the lighting device 100 is further achieved in some examples by printing the printed circuit arrangement 120 directly onto the input surface of the opaque cover portion 160, i.e., without using an additional substrate. In some examples, the light emitting element 110 is attached directly to the inward surface of the opaque cover portion 160, thereby further reducing a minimal thickness of the lighting device 100 and improving a heat transfer from the light emitting element 110 to the opaque cover portion 160.

[0038] In some examples, the light deflecting member 130 constitutes an exterior surface of the lighting device 100 and, accordingly, of a vehicle or another appliance on which the lighting device 100 is intended to be mounted. In accordance with the intended use of the lighting device 100, the light deflecting member 130 is configured in some examples to comply with requirements posed to an outside surface in the respective context, for example, in respect of at least one of a mechanical stability, a chemical stability, a weather-proofness, haptic characteristics, a crash performance, etc.

[0039] Figs. 2A to 2D show different views of a lighting device 200. Unless differently clear from the drawings and the following description, the above description of the lighting device 100 applies analogously to the lighting device 200 and its components.

[0040] Fig. 2A shows a frontal view, corresponding to an exterior appearance, of the lighting device 200. The lighting device 200 comprises a light deflecting member 230 which extends adjacent an opaque cover portion 260 of the lighting device 200. In the shown example, the opaque cover portion 260 extends along an entire circumference of the light deflecting member 230. In the area of the light deflecting member 230, a plurality of light deflecting structures 240 are arranged. As described in connection with Fig. 1, the light deflecting structures 240 serve for deflecting light which has been produced and in-coupled into the light deflecting member 230 by a plurality of light emitting elements 210, which are arranged at an inward surface of the opaque cover portion 260, through an out-coupling surface 234 of the light deflecting member 230. In the shown example, the light deflecting structures 240 comprise an array of linear light deflecting structures which are arranged parallel to each other over essentially an entire area of the light deflecting member 230.

[0041] Fig. 2B shows a rear view of the lighting device 200. As shown in Fig. 2B, a housing 270 of the lighting device 200 extends essentially along an entire rear surface of the lighting device 200. The housing 270 facilitates in some examples a handling of the lighting device 200, a management of heat at the rear surface of the lighting device 200 and / or a mounting of the lighting device 200 on a vehicle or another appliance.

[0042] Fig. 2C shows a cutaway view on the rear side of the lighting device 200. The view in Fig. 2C corresponds to the view in Fig. 2B, after removal of the housing 270.

[0043] Behind the opaque cover portion 260, a plurality of light emitting elements 210 is arranged and operated via a printed circuit arrangement 220. Light produced by the light emitting elements 210 is in-coupled to the light deflecting member 230 at an in-coupling surface 232 and propagates by internal reflection in the light deflecting member 230. The multiple light deflecting structures 240 are arranged on an inward surface 236 of the light deflecting member 230 to produce partial out-coupling of the in-coupled light at each position of any of the light deflecting structures 240 over an entire length of the light deflecting member 230.

[0044] Fig. 2D shows a vertical cross section of the lighting device 200, in plane of the light emitting elements 210.

[0045] The housing 270 is attached to the opaque cover portion 260, for example, by gluing or welding. In some examples, the housing comprises polycarbonate or similar plastic material.

[0046] In the shown example, the light emitting elements 210 are arranged together with the printed circuit arrangement 220 on a substrate, for example, a paper substrate. The substrate is attached to the inward surface of the opaque cover portion 260, for example, by hot stamping or heat conductive gluing.

[0047] In some examples, a thickness of the lighting device 200 is in a range between 2 and 20 millimeters, in particular in a range between 4 and 16 millimeters, preferably in a range between 6 and 14 millimeters, more preferably in a range between 8 and 12 millimeters.

[0048] Fig. 3 shows schematically and exemplarily a vehicle 300. The vehicle 300 comprises multiple lighting devices 310. The lighting devices 310 are lighting devices as described in connection with the lighting devices 100, 200 in Figs. 1 to 2D.

[0049] In the shown example, the lighting devices 310 are symmetric stoplights of the vehicle 300. In other examples, lighting devices as described herein are used additionally, or as an alternative, as different vehicle lights, including, for example, back lights and / or indicator lights.

[0050] Moreover, the above examples have been described, especially, in connection with exterior vehicle lights. However, it will be understood that some or all of the described advantages are also achievable in connection with other uses of a lighting device.

Claims

1. Lighting device (100; 200; 310), in particular for use as an exterior vehicle light, comprising: - at least one light emitting element (110; 210), - a light deflecting member (130; 230) comprising: ∘ an in-coupling surface (132; 232) arranged for receiving light (LE) which has been emitted by the light emitting element (110; 210), ∘ at least one light deflecting structure (140; 240) for deflecting light (LI) which has been in-coupled to the light deflecting member (130; 230) via the in-coupling surface (132; 232), and ∘ an out-coupling surface (134; 234) arranged for out-coupling, towards an environment of the lighting device (100; 200; 310), light (LO) which has been in-coupled to the light deflecting member (130; 230) via the in-coupling surface (132; 232) and deflected by means of the light deflecting structure (140; 240), and - an opaque cover portion (160; 260) covering the at least one light emitting element (110; 210) at least partially with respect to the environment of the lighting device (100; 200; 310), wherein the at least one light emitting element (110; 210) is arranged on an inward surface of the opaque cover portion (160; 260).

2. Lighting device according to claim 1, wherein the opaque cover portion (160; 260) comprises heat conductive material, in particular a heat conductive resin composition and / or heat conductive plastic material.

3. Lighting device according to claim 1 or claim 2, further comprising at least one printed circuit arrangement (120; 220) for operating the at least one light emitting element (110; 210), the at least one printed circuit arrangement (120; 220) arranged on the inward surface of the opaque cover portion (160; 260).

4. Lighting device according to any one of the preceding claims, wherein the at least one light emitting element (110; 210) comprises at least one light emitting diode, LED.

5. Lighting device according to any one of the preceding claims, wherein the opaque cover portion (160; 260) is integrally formed with at least a portion of the light deflecting member (130; 230).

6. Lighting device according to any one of the preceding claims, wherein the light deflecting member (130; 230) is configured to function as a light guide for guiding light (LI) which has been in-coupled to the light deflecting member (130; 230) via the in-coupling surface (132; 232) towards the light deflecting structure (140; 240).

7. Lighting device according to any one of the preceding claims, wherein the in-coupling surface (132; 232) corresponds to a side surface of the light deflecting member (130; 230) and the out-coupling surface (134; 234) corresponds to an outward surface of the light deflecting member (130; 230).

8. Lighting device according to any one of the preceding claims, wherein the light deflecting member (130; 230) has an at least essentially planar shape, in particular an at least essentially curved or flat planar shape, in at least a region of the light deflecting member (130; 230), said region including the in-coupling surface (132; 232), the light deflecting structure (140; 240) and the out-coupling surface (134; 234).

9. Lighting device according to any one of the preceding claims, wherein the light deflecting member (130; 230) is configured to refract light (LO) which has been deflected by means of the light deflecting structure (140; 240), in particular to function as an output lens of the at least one lighting device (100; 200; 310).

10. Lighting device according to any one of the preceding claims, wherein the light deflecting member (130; 230) is integrally formed in at least a region of the light deflecting member (130; 230), said region including the in-coupling surface (132; 232) and the out-coupling surface (134; 234).

11. Lighting device according to any one of the preceding claims, wherein the at least one light deflecting structure (140; 240) is arranged at an inward surface (136; 236) of the light deflecting member (130; 230).

12. Lighting device according to any one of the preceding claims, wherein the at least one light deflecting structure (140; 240) comprises at least one of a surface structure or an optical microstructure.

13. Lighting device according to any one of the preceding claims, further comprising a housing (170; 270) which accommodates the at least one light emitting element (110; 210) and / or the light deflecting member (130; 230).

14. Lighting device according to any one of the preceding claims, wherein the lighting device (100; 200; 310) is configured to function as at least one of a back light, a stop light and / or an indicator light of a vehicle (300).

15. Vehicle (300) comprising a lighting device according to any one of claims 1 to 14.

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