Lighting device for a vehicle, vehicle window and vehicle roof

Abstract

Lighting device (20) for a vehicle, comprising - a light guiding element (1), - a light source (2) for generating light rays (8) and - a light coupling element (3) with an input surface into which the light rays (8) of the light source (2) are coupled, and an output surface which is adjacent to the light guiding element (1) and from which the light rays (8) coupled into the light coupling element (3) are coupled out into the light guiding element (1), where an optical silicone (4) is arranged between the light guiding element (1) and the starting surface, wherein the material of the light guiding element (1) differs from the material of the light coupling element (3) and / or an adhesion promoter is applied to the starting surface and / or a non-stick coating is applied to the light guiding element (1) so that the optical silicone (4) adheres only to the light coupling element (3) and so that the light guiding element (1) and the light coupling element (3) are detachably connected to each other by the optical silicone (4), wherein the light source (2) and the light coupling element (3) are arranged in a housing of at least two parts, wherein a first housing section (5) is fixed to the light guiding element (1) and a second housing section (6) is connected to the first housing section (5) to close the housing, wherein the second housing section (6) is snapped into the first housing section (5) to connect the first housing section (5) and the second housing section (6), wherein the light source (2) and the light coupling element (3) are arranged on a common support plate (7), wherein the support plate (7) is either connected to the second housing section (6) or at least partially forms the second housing section (6), characterized in that by snapping the second housing section (6) into the first housing section (5) the starting surface of the light coupling element (3) arranged on the carrier plate (7) is pressed and fixed against the light guiding element (1) with the optical silicone (4) applied to the starting surface.

Description

[0001] The invention relates to a lighting device for a vehicle, comprising a light-guiding element, a light source for generating light rays and a light-coupling element with an input surface into which the light rays of the light source are coupled, and an output surface which lies against the light-guiding element and from which the light rays coupled into the light-coupling element are coupled out into the light-guiding element.

[0002] A lighting device is known from DE 10 2021 122 986 A1. The lighting device comprises a vehicle window into which light beams are coupled by means of a light coupling device. The light coupling device is attached to a light-conducting layer of the vehicle window, in particular by means of adhesive bonding, encapsulation material, adhesive tape, or a holding or clamping device.

[0003] US 10 962 197 B2 discloses a waveguide illumination system comprising a planar layer of optically transmissive material. Side-emitting LEDs are positioned adjacent to a major surface of the planar layer and optically coupled to the planar film. The planar layer is designed to guide light by means of optical transmission and total internal reflection. Light extraction features arranged along the predominant light propagation path extract light from the planar layer and radiate the light in a surface-normal direction.

[0004] Attaching the light coupling device to the light-conducting layer using adhesive, potting material, or adhesive tape has the disadvantage that replacing the light coupling device requires replacing the entire lighting system. Consequently, the entire vehicle windshield would have to be replaced, even if only the light coupling device were defective.

[0005] The fastening of the light coupling device to the light-guiding layer by means of a holding or clamping device has the disadvantage that component tolerances of the light coupling device and the vehicle window, which can usually also be curved, ensure that the coupling of the light from the light coupling device into the light-guiding layer is reduced.

[0006] The invention is based on the object of designing a lighting device for a vehicle of the type mentioned at the outset, in which, on the one hand, components can be easily replaced and, in addition, component tolerances can be compensated during assembly and repair.

[0007] This object is achieved according to the invention in the lighting device in that an optical silicone is arranged between the light-guiding element and the output surface, wherein the material of the light-guiding element differs from the material of the light-coupling element and / or an adhesion promoter is applied to the output surface and / or an anti-stick coating is applied to the light-guiding element, so that the optical silicone adheres only to the light-coupling element and so that the light-guiding element and the light-coupling element are detachably connected to one another by the optical silicone.

[0008] According to the invention, an optical silicone sealant connects the output surface of the light coupling element to the light-guiding element. The optical silicone sealant adheres only to the output surface of the light coupling element. The optical silicone sealant does not adhere to the light-guiding element. By inserting an optical silicone sealant between the light-guiding element and the output surface of the light coupling element, component tolerances and the effects of a possible curvature of the light-guiding element can be compensated.

[0009] Optical silicones are silicone elastomers that are transparent to light in the visible spectrum and to UV rays. Optical silicones belong to the so-called liquid silicone rubber (LSR) and thus have a low viscosity. This makes them suitable for processing using injection molding. Furthermore, optical silicones are temperature-stable within a range of -40°C to 150°C, elastic, and mechanically stable. Another advantage of optical silicone is that its refractive index is very similar to that of glass, although optical silicone has a lower density than glass, so components made of optical silicone are lighter than their glass counterparts.

[0010] Adhesion within the meaning of the invention means that a permanent bond is created between the optical silicone and the light coupling element, which can only be removed without leaving residue using tools or chemicals. Non-adhesion within the meaning of the invention means that the optical silicone can be removed from the light-guiding element without leaving residue, e.g., by peeling or detaching the optical silicone.

[0011] According to the invention, the material of the light-guiding element is different from the material of the light-coupling element and / or an adhesion promoter is applied to the output surface and / or an anti-stick coating is applied to the light-guiding element.

[0012] Different materials for the light-guiding element and the light-coupling element can be, for example, different types of glass and / or plastics that have the same or at least a similar refractive index. An identical or at least similar refractive index is required so that the coupling of light rays from the light-coupling element into the light-guiding element can occur with low loss. However, the material for the light-guiding element must differ from the material of the light-coupling element in terms of surface energy. Different surface energies enable the optical silicone to adhere to the light-coupling element, while the optical silicone does not adhere to the light-guiding element. Depending on the optical silicone used, the surface of the light-guiding element can be polar and the surface of the light-coupling element can be non-polar.Likewise, depending on the optical silicone used, the surface of the light guide element could be non-polar and the surface of the light coupling element could be polar.

[0013] Alternatively or additionally, an adhesion promoter is applied to the output surface of the light coupling element. A adhesion promoter enables substances to adhere to a surface that would not adhere to the surface without the adhesion promoter. This allows the light coupling element and light guide element to be made of the same material, and an optical silicone to be selected that inherently adheres neither to the light coupling element nor to the light guide element. By applying the adhesion promoter to the output surface of the light coupling element, the optical silicone can then adhere to the output surface of the light coupling element, while no adhesive bond is formed to the light guide element. When selecting a suitable adhesion promoter, care must be taken to ensure that it is transparent in the visible light spectrum.

[0014] Alternatively or additionally, a non-stick coating is applied to the light-guiding element. A non-stick coating prevents a substance that would normally adhere to a surface from adhering to the surface. This allows the light-coupling element and light-guiding element to be made of the same material, and an optical silicone to be selected that adheres to both the light-coupling element and the light-guiding element. By applying the non-stick coating to the light-coupling element, no adhesive bond is created between the light-guiding element and the optical silicone, while the optical silicone adheres to the output surface of the light-coupling element. When selecting a suitable non-stick coating, care must be taken to ensure that it is transparent in the visible light spectrum.

[0015] According to the invention, the light source and the light coupling element are arranged in an at least two-part housing, wherein a first housing section is fixed to the light-guiding element and a second housing section is connected to the first housing section in order to close the housing. An at least two-part housing in which the light source and the light coupling element are arranged, in which a first housing section is fixed to the light-guiding element and a second housing section is connected to the first housing section in order to close the housing, enables the components within the housing, i.e. at least the light source and the light coupling element, to be easily accessible in the event of repairs. The first housing section can, for example, be a holding element which is fixed to the light-guiding element by means of an adhesive. The second housing section can then be connected to the holding element and thus form the housing.

[0016] According to the invention, the second housing section is snapped into the first housing section to connect the first housing section and the second housing section. Snapping the second housing section into the first housing section allows for easy assembly of the housing.

[0017] According to the invention, the light source and the light coupling element are arranged on a common carrier plate, wherein the carrier plate is either connected to the second housing section or at least partially forms the second housing section. The carrier plate can, in particular, be a printed circuit board (PCB). By integrating the carrier plate, the overall housing can be designed more compactly. Furthermore, ESD protection can be ensured if the carrier plate is connected to the second housing section.

[0018] According to the invention, by snapping the second housing section into the first housing section, the output surface of the light coupling element arranged on the carrier plate, with the optical silicone applied to the output surface, is pressed against the light-guiding element and fixed in place. This embodiment makes it possible for the arrangement of the light coupling element on the carrier plate, which is either connected to the second housing section or at least partially forms the second housing section, to be pressed against the light-guiding element and also fixed in place by snapping the second housing section into the first housing section with the optical silicone applied to the output surface of the light coupling element. In this context, pressing means that a contact pressure is present with which the output surface of the light coupling element with the applied optical silicone is pressed against the light-guiding element.This ensures that no air pockets form between the optical silicone on the light coupling element's upstream surface and the light guide element. Furthermore, it ensures that the angular position between the light coupling element and the light guide element is correct to avoid coupling losses.

[0019] Furthermore, the object is achieved by a vehicle window with a lighting device according to the invention. The vehicle window forms the light-guiding element or the light-guiding element forms a light guide within the vehicle window.

[0020] Furthermore, the object is achieved by a vehicle roof with a vehicle window according to the invention.

[0021] Embodiments of the invention are explained in more detail below with reference to a drawing.

[0022] The following shows: Fig. 1 a cross-section of a lighting device with a light guide element, a light coupling element, a light source and a housing Fig. 2 a plan view of a lighting device according to Fig. 1 Fig. 3 a plan view of a vehicle roof with a vehicle window with a plurality of lighting devices

[0023] In the Fig. 1 shows a cross-section of a lighting device 20. The lighting device 20 has a light-guiding element 1. The light-guiding element 1 is made of glass here, but could also be made of plastic. A first housing section 5 of a housing is glued to the light-guiding element 1. A second housing section 6 is snapped into the first housing section 5, so that the housing is closed. A carrier plate 7 is arranged within the housing and is connected to the second housing section 6. The carrier plate 7 could also be integrated into the second housing section 6 or form it. A light source 2 and a light coupling element 3 are arranged on the carrier plate 7. The light source 2 is an LED that emits light rays 8. The light rays 8 are coupled into the light coupling element 3. The light coupling element 3 is prism-shaped and has a lens on the side facing the light source 2.Other shapes can also be considered for the light coupling element 3, and a lens is also optional. The light coupling element 3 is made of glass here, but could also be made of plastic. The light rays 8 are coupled into the light coupling element 3 through the lens. The light rays 8 are coupled out at an output surface of the light coupling element 3. An optical silicone 4 is applied flatly to the output surface. To ensure that the optical silicone 4 adheres to the output surface of the light coupling element 3, an adhesion promoter (not shown) was applied to the output surface of the light coupling element 3 before the optical silicone 4 was applied to the output surface of the light coupling element 3. The optical silicone 4 thus adheres to the output surface of the light coupling element 3.By snapping the second housing section 6 into the first housing section 5, the output surface of the light coupling element 3, with the optical silicone 4 applied to the output surface of the light coupling element 3, is pressed or pressed against the light-guiding element 1. To prevent the optical silicone 4 from adhering to the light-guiding element 1 and to ensure a detachable connection between the light-guiding element 1 and the light coupling element 3, a non-stick coating (not shown) has been applied to the light-guiding element 1. By snapping the second housing section 6 into the first housing section 5, it is also ensured that the output surfaces of the light coupling element 3 and the light-guiding element 1 are aligned with one another in such a way that coupling losses are avoided.

[0024] In Fig. 2 is a plan view of a lighting device 20 according to Fig. 1. For clarity, only the light coupling element 3, the optical silicone 4, and the light guide element 1 are shown.

[0025] In Fig.3 shows a plan view of a vehicle roof 10 with a vehicle window 11 having a plurality of lighting devices 20. A plurality of lighting devices 20 are arranged on the vehicle window 11, wherein for the sake of clarity only the light coupling elements 3 of the lighting devices 20 are shown. In this exemplary embodiment, the vehicle window 11 forms the light guide element 1 for all lighting devices 20. In other words, the light beams 8 of a plurality of LEDs 2 are coupled into the vehicle window 11 via the corresponding light coupling elements 3, so that the vehicle window 11 functions as a light guide element 1. The lighting devices 20 are controlled via a control unit 9. The lighting devices 20 are combined into a first group 12 and a second group 13. The lighting devices 20 of the first group 12 andThe second group 13 can alternatively be arranged together in one housing. The first and second groups 12, 13 are connected to the control unit 9 via a line 14.

Claims

[1] Lighting device (20) for a vehicle, comprising - a light-guiding element (1), - a light source (2) for generating light rays (8) and - a light coupling element (3) with an input surface into which the light rays (8) of the light source (2) are coupled, and an output surface which lies against the light-guiding element (1) and from which the light rays (8) coupled into the light coupling element (3) are coupled out into the light-guiding element (1), where an optical silicone (4) is arranged between the light-guiding element (1) and the output surface, wherein the material of the light-guiding element (1) differs from the material of the light-coupling element (3) and / or an adhesion promoter is applied to the output surface and / or an anti-stick coating is applied to the light-guiding element (1), so that the optical silicone (4) adheres only to the light-coupling element (3) and so that the light-guiding element (1) and the light-coupling element (3) are detachably connected to one another by the optical silicone (4), wherein the light source (2) and the light coupling element (3) are arranged in an at least two-part housing, wherein a first housing section (5) is fixed to the light-guiding element (1) and a second housing section (6) is connected to the first housing section (5) in order to close the housing, wherein the second housing section (6) is snapped into the first housing section (5) to connect the first housing section (5) and the second housing section (6), wherein the light source (2) and the light coupling element (3) are arranged on a common carrier plate (7), wherein the carrier plate (7) is either connected to the second housing section (6) or at least partially forms the second housing section (6), characterized by that by snapping the second housing section (6) into the first housing section (5), the output surface of the light coupling element (3) arranged on the carrier plate (7) is pressed and fixed against the light guide element (1) with the optical silicone (4) applied to the output surface. [2] Vehicle window (11) with a lighting device (20) according to claim 1, characterized bythat the vehicle window (11) forms the light-guiding element (1) or the light-guiding element (1) forms a light guide within the vehicle window (11). [3] Vehicle roof (10) with a vehicle window (11) according to claim 2.

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