Arrangement of a lighting device in a vehicle and method for manufacturing an external surface element of a vehicle

Abstract

Arrangement of a lighting device (3) in a vehicle, - wherein the lighting device (3) comprises at least one light source (4) and a light guide (7) which has a light coupling surface (9) at which light emitted from the light source (4) can be coupled in, and a light coupling surface (10) at which light coupled into the light guide (7) can be coupled out, characterized in that - the vehicle (1) has an outer surface element (2) which is a window pane of the vehicle (1) or a flat body part, by which the light source (4) is completely enclosed and into which the light guide (7) is cast at least partially. - the optical fiber (7) is made of a material which has a higher melting point than the material of which the outer surface element (2) is made.

Description

[0001] The present invention relates to a lighting device arrangement in a vehicle. The lighting device of this arrangement comprises at least one light source and a light guide. The light guide has a light coupling surface, at which light emitted by the light source can be coupled, and a light coupling surface, at which light coupled into the light guide can be coupled out. Furthermore, the invention relates to a method for manufacturing an exterior surface element of a vehicle.

[0002] The lighting devices of a vehicle, whose light emission is directed outwards to provide the vehicle's lighting functions, are typically housed in lighting modules. These modules are located at the front of the vehicle to provide headlights, and at the rear to provide rear-facing lights. Recesses are provided in the vehicle body to accommodate these lighting modules.

[0003] For aerodynamic and design reasons, the installation space available for lighting devices is very limited. Therefore, there is a need to provide lighting device arrangements in vehicles that require minimal installation space.

[0004] From DE 10 2009 055 733 A1, a lighting device for a vehicle is known, comprising a light guide element and a light source. The light guide element has a light entry surface and a light exit surface. The depth of the lighting device perpendicular to the light exit surface corresponds essentially entirely to the depth of the light guide element. The lighting device can be used, in particular, in the vehicle interior, for example as a headliner light, as a light in the area of ​​the vehicle doors or in the area of ​​the vehicle seat, or as lighting for the instrument panel. Furthermore, the lighting device can also be used in the vehicle exterior, for example as license plate lighting, as a turn signal indicator, as a warning light, or as a reversing light.

[0005] A vehicle light with a one-piece light guide and aperture unit is known from DE 10 2006 035 842 A1. The vehicle light is installed in a cover cap of an external rearview mirror.

[0006] Furthermore, DE 102 61 772 A1 discloses a lighting unit for a vehicle which uses light-emitting diodes mounted on a flexible conductive film as the light source. To enable easy installation of the flexible conductor in the desired position, it is at least partially embedded in a dimensionally stable component. This component provides the conductor with dimensional stability, allowing for easy installation. The conductor can, for example, be enclosed by a carrier or a reflector.

[0007] Finally, US patent 2008 / 0239748 A1 describes a lighting device for a vehicle, which is used in the vehicle's interior. The lighting device uses a light-emitting diode (LED) as its light source. A light guide is used to transmit the light emitted by the LED.

[0008] DE 10 2008 009 138 A1 relates to side-emitting refractive index-matched fibers and processes for their production, as well as fiber bundles containing side-emitting refractive index-matched fibers and sheet structures and their applications.

[0009] DE 197 06 043 A1 concerns various plastic windows for a motor vehicle door and motor vehicle doors with corresponding plastic windows.

[0010] DE 10 2004 025 385 A1 describes an external rearview mirror for vehicles, in particular motor vehicles, with a mirror housing with at least one mirror glass, which is arranged on a mirror glass support and surrounded by a frame in which at least one light source of a recessed light is housed.

[0011] The present invention is based on the objective of providing an arrangement and a method of the type mentioned at the outset, by which the lighting device can be integrated into the vehicle in such a way that it occupies as little installation space as possible.

[0012] According to the invention, this problem is solved by an arrangement having the features of claim 1 and a method having the features of claim 8.

[0013] The arrangement according to the invention is characterized in that the vehicle has an outer surface element which at least partially encloses the light guide, and the light guide is made of a material which has a higher melting point than the material of which the outer surface element is made.

[0014] In the arrangement according to the invention, the lighting device is thus integrated into an outer surface element of the vehicle. This results in the lighting device occupying very little installation space.

[0015] In this arrangement, the light guide of the lighting device is at least partially enclosed by the outer surface element. In the area where the light guide is enclosed by the outer surface element, the light guide is in direct contact with the material of the outer surface element. For example, it is embedded or cast into the outer surface element.

[0016] Furthermore, not only the light guide but also other components of the lighting device, such as the light source, can be enclosed by the outer surface element. In this case, the entire lighting device is enclosed by the outer surface element. To supply the light source with power, the outer surface element has a connection point through which a power supply line can be connected to the light source.

[0017] Since, in the arrangement according to the invention, the material of the light guide has a higher melting point than the material of the outer surface element, the advantage arises that the light guide can be overmolded with the liquid material of the outer surface element without melting during this process. For example, the light guide can be cast into the outer surface element using injection molding.

[0018] According to one embodiment of the arrangement according to the invention, the light output surface is at least partially enclosed by the outer surface element. The area of ​​the lighting device from which light is emitted to provide a lighting function is thus integrated into the outer surface element. The light exiting the light guide at the light output surface can pass through the outer surface element, which in this case is partially transparent in this area. Furthermore, the outer surface element can also enclose the light output surface laterally, so that the light output surface of the light guide forms an outer surface from which the light is emitted. In this way, the lighting device can be integrated into the outer surface element very flexibly and with minimal installation space.

[0019] The optical fiber of the arrangement according to the invention consists in particular of glass or a glass-like material. The glass-like material is particularly similar to glass with regard to its melting point and optical properties.

[0020] Since the transition from melt to crystal in glass does not occur spontaneously, but rather within a transformation range where the material's viscosity increases with decreasing temperature, the melting point in this case is understood to be the temperature at which the glass transitions into a characteristic amorphous state (glass transition). At this glass transition, the coefficient of thermal expansion changes abruptly. This temperature is around 600°C. It is, in particular, much higher than the melting point of the material of the outer surface element.

[0021] The outer surface element consists, for example, of a plastic, in particular polycarbonate. The melting point of polycarbonate is below 280°C. Polycarbonates can advantageously be processed by injection molding. The processing temperature is, for example, in a range between 280°C and 320°C. To manufacture the arrangement according to the invention, it is therefore possible to overmold a glass light guide with the plastic of the outer surface element using injection molding and thus embed the light guide in the plastic outer surface element. In this way, the arrangement can be manufactured very cost-effectively.

[0022] The outer surface element of the arrangement according to the invention is, in particular, a window pane of the vehicle, especially the rear window of the vehicle. However, the outer surface element can also be formed by the windshield or side window of the vehicle. The window pane of the vehicle is characterized in that it is transparent in at least one area, allowing a view out of the vehicle's interior. However, it is not necessary for the window pane to be transparent in the area where the light guide is embedded. In this area, the window pane can also be opaque, while ensuring that light is emitted outwards from the light-emitting surface of the light guide.

[0023] Furthermore, the outer surface element can be a body panel. In this case, the light guide is enclosed by the flat body panel. However, the light guide is not only located on the surface of the body panel or in a recess of the body panel. It is at least partially completely enclosed by the body panel, so that the thickness of the flat body panel in this area is greater than the extent of the light guide in a direction parallel to the thickness of the flat body panel.

[0024] According to a further development of the arrangement according to the invention, the outer surface element, in the area where the light-emitting surface is enclosed, is transparent on the side facing out of the light guide in the direction of light emission and opaque on the opposite side. An opaque design means that the outer surface element is not completely transparent, but rather partially opaque or cloudy. In this area, the outer surface element is particularly completely opaque.

[0025] The outer surface element can thus have a layered structure, consisting of an outward-facing, translucent layer and an inward-facing, opaque layer. The light-emitting surface is located in the transition zone between these two layers, with the light exiting into the translucent layer. This allows the light exiting the surface to be emitted outwards through the outer surface element, while preventing an observer from seeing through it, either from the outside or the inside. This increases the contrast of the illuminated surface of the lighting device for an external observer.

[0026] According to a further development of the arrangement according to the invention, this arrangement further comprises at least one stabilizing element which, for the purpose of stabilizing the outer surface element, is at least partially enclosed by the outer surface element or is integrally formed with the outer surface element. This ensures that the optical fiber embedded in the outer surface element does not break when forces are exerted on the outer surface element. Particularly when the optical fiber is made of glass, there is a risk that the glass optical fiber will break if the outer surface element is torsionally twisted or struck. The stabilizing element protects the optical fiber against breakage.

[0027] The stabilizing element is positioned particularly close to the light guide enclosed by the outer surface element. This ensures particularly good protection of the light guide.

[0028] According to a further embodiment, the light guide enclosed by the outer surface element is elongated. Similarly, the stabilizing element is elongated, with the longitudinal extent of the light guide enclosed by the outer surface element and the stabilizing element being essentially parallel. The stabilizing element can, for example, be designed as a stabilizing, supporting, or foundation metal. Furthermore, the stabilizing element can be a reinforcing rib or a profile. The stabilizing element can also be made of a plastic and molded onto the plastic outer surface element. However, it can also be made of another material, such as metal. The stabilizing element can be implanted into the outer surface element by an overmolding process, so that it is essentially completely cast into the outer surface element.

[0029] By enclosing the light guide and, if applicable, the light-emitting surface within the outer surface element, the light guide is held in place without the need for additional fasteners. Furthermore, this creates a floating appearance for the light guide and / or light-emitting surface within the outer surface element, which is aesthetically advantageous.

[0030] The invention further relates to a method for manufacturing an exterior surface element of a vehicle. This exterior surface element can be used, in particular, in the arrangement of a lighting device in a vehicle according to the invention. In the method, a light guide with a light coupling surface and a light coupling surface is formed. The light guide is designed and calculated, in particular, such that the geometric characteristics are optimally configured to achieve the desired emission characteristics of a lighting device used in conjunction with the manufactured exterior surface element. The light guide is then positioned in an injection mold. To form the exterior surface element, the light guide is then overmolded with a material that has a lower melting point than the material from which the light guide is made.During the injection molding process, this ensures that the light guide is not melted, but rather enclosed by the outer surface element. Specifically, it is encased or embedded within the material of the outer surface element.

[0031] The shape of the light guide can be adapted to any geometry of the lighting device and the outer surface element. The light guide can be formed from profiles with round or other geometries. To achieve the lowest possible weight, the light guide can also have a flat or foil-like design.

[0032] In the following, an exemplary embodiment of the arrangement and method according to the invention is explained with reference to the figures. Fig. Figure 1 shows a vehicle with an embodiment of the arrangement according to the invention, Fig. Figure 2 shows a schematic detail view of the embodiment of the arrangement according to the invention, Fig. Figure 3 shows a cross-section AA of the in Fig. 1 arrangement shown and Fig. Figure 4 shows the steps of the exemplary embodiment of the method according to the invention.

[0033] The embodiment described below relates to the arrangement of a rear light 3 in the rear window 2 of a vehicle 1. Instead of a rear light 3, the lighting device could also be any other light or headlight of the vehicle that is integrated into a vehicle window or an outer flat body part of the vehicle 1.

[0034] As in Fig. As shown in Figure 1, a rear window 2 is attached to the vehicle 1 in a manner known per se. The rear window 2 is made of a plastic, specifically polycarbonate. It was manufactured by injection molding, as will be explained later. The rear window 2 is divided into a transparent area 2-1 and an opaque area 2-2. Through area 2-2 of the rear window 2, one can see into the interior of the vehicle 1 from the outside and vice versa. Through area 2-2, one cannot see into the interior of the vehicle.

[0035] In the area 2-2 of the rear window 2, luminous surfaces 16 are formed. These luminous surfaces 16 are provided by light-emitting surfaces 10 of the lighting device 3 described later. When the lighting device 3 is switched on, i.e., when the light source 4 of the lighting device 3 emits light, at least one luminous surface 16 illuminates and provides a lighting function for the vehicle. In this way, for example, a tail light, a brake light, a reversing light, or a turn signal can be provided. Furthermore, a rear fog light can also be provided by a luminous surface 16.

[0036] The design of the arrangement of the lighting device 3 in the vehicle is described with reference to Fig. 2 explained: The lighting device 3 comprises a light source 4, which in this case is designed as a light-emitting diode (LED). The LED 4 is arranged on a circuit board, which is connected to a terminal 6 via an electrical line 5. A power supply line can be connected to the terminal 6, via which the LED 4 can be electrically controlled.

[0037] In the direction of light emission from the light-emitting diode 4, the light coupling surface 9 of an optical fiber 7 is arranged. The optical fiber 7 also has a light output surface 10. The light coupled in via the light coupling surface 9 is guided in the optical fiber 7 by total internal reflection via a light-guiding rod-shaped section 8 to the region of the optical fiber 7 which has the light output surface 10. At the light output surface 10, the optical fiber 7 has a geometry that causes the light to exit the optical fiber 7, thus providing the luminous surface 16.

[0038] In the embodiment shown here, the electrical conductor 5, the LED 4, and the light guide 7 are located inside the rear window 2. The lighting device 3 is thus completely enclosed by the rear window. It is embedded in the rear window 2. However, it would also be possible for only the light guide 7 to be enclosed by the rear window 2, with the light coupling surface 9 located at an end face of the rear window 2. Light from an LED 4 located outside the rear window 2 can be coupled there. Furthermore, it would be possible for the light guide 7 to form a section of an outer surface of the rear window 2; in particular, the light coupling surface 10 could be a surface flush with the outer surface of the rear window 2.

[0039] The light guide 7 is made of a material with a higher melting point than the material of the rear window 2. The melting point of the light guide 7 material is therefore higher than the melting point of polycarbonate. In the present embodiment, the light guide 7 is made of glass.

[0040] In Fig. 3 is the cross-section AA of the Fig. Figure 1 shows that the light guide 7 is completely enclosed by the rear window 2, being embedded in the rear window 2 without any gap or other space. Furthermore, it can be seen that the rear window 2 has a layered structure in the opaque area 2-2 in the direction of its thickness. The outward-facing layer 12 of the rear window 2 is transparent. It may optionally be tinted to filter the light emission from the lighting device 3. The inward-facing layer 13, on the other hand, is opaque, in particular completely opaque. The rod-shaped light guide 7 is arranged in the transition area between the two layers 12 and 13.The light extraction surface 10 of the light guide 7 is located in the transparent layer 12, so that light rays L exiting the light extraction surface 10 pass through the transparent layer 12 of the rear window 2 and provide the luminous surface 16 with the desired emission characteristic.

[0041] Adjacent to each light guide 7 are stabilizing elements 11 enclosed by the opaque layer 13 of the rear window 2. The stabilizing elements 11 can, for example, be metal profiles extending parallel to the associated adjacent light guide 7. The stabilizing elements 11 prevent the glass light guide 7 from breaking if the rear window 2 is subjected to torsion or impact.

[0042] In the present embodiment, a reflector 14 is embedded in the rear window 2 in addition to the lighting devices 3. For this purpose, a gas-filled cavity 15 is formed in the opaque layer 13 of the rear window 2. The surface of the opaque layer 13 in this cavity 15 is provided with a reflective coating to form the reflector 14. Thus, light from the outside can pass through the transparent layer 12 of the rear window 2, be reflected by the reflector 14, and then pass back through layer 12, so that the incident light is reflected.

[0043] The following describes an exemplary embodiment of a method for manufacturing an outer surface element of a vehicle 1 with reference to Fig. 4 described. In the exemplary embodiment, the arrangement of the lighting device 3 in the rear window 2 of the vehicle 1 described above is explained: First, a light guide 7 with a light coupling surface 9 and a light coupling surface 10 is formed in step S1. The geometry of the light guide 7 is chosen such that light coupled in at the light coupling surface 9 is guided to the light coupling surface 10 and coupled out there with a radiation characteristic that corresponds to the desired lighting function of the vehicle 1. As described above, the light guide 7 is made of glass.

[0044] The optical fiber 7 thus formed is positioned in an injection mold in step S2. Furthermore, a unit formed from the terminal 6 of the electrical conductor 5 and the light-emitting diode 4 attached to the circuit board is positioned in the injection mold such that light emission from the light-emitting diode 4 is coupled into the optical fiber 7 via the light coupling surface 9.

[0045] Then, in step S3, the stabilizing elements 11 are positioned at the desired positions in the injection mold.

[0046] The injection mold has the shape of the vehicle's rear window 2. In step S4, a lower layer 13 is injected into the injection mold. This layer 13 consists of black-colored polycarbonate in area 2-2 and transparent polycarbonate in area 2-1. Layer 13 completely encloses the stabilizing elements 11 and partially encloses the light guides 7.

[0047] In step S5, another layer 12 of transparent polycarbonate is injected, which completely encloses the remaining elements of the lighting unit 3. After the polycarbonate has cured, the resulting rear window 2 can be attached to the vehicle 1. The lighting unit 3 can be electrically connected to a power supply line or a lighting control unit via connection 6. Reference symbol list 1 vehicle 2 Rear window 2-1, 2-2 areas of the rear window 3 Lighting equipment 4 Light source, LED 5 electrical lines 6 connection 7 optical fibers 8 light-conducting section of the light guide 9 Light coupling area 10 Light extraction area 11 stabilizing elements 12th layer of the rear window 13th layer of the rear window 14 Reflector 15 Cavity 16 illuminated surfaces

Claims

[1] Arrangement of a lighting device (3) in a vehicle, - wherein the lighting device (3) comprises at least one light source (4) and a light guide (7) which has a light coupling surface (9) at which light emitted from the light source (4) can be coupled in, and a light coupling surface (10) at which light coupled into the light guide (7) can be coupled out, characterized by , that - the vehicle (1) has an outer surface element (2) which is a window pane of the vehicle (1) or a flat body part, by which the light source (4) is completely enclosed and into which the light guide (7) is cast at least partially. - the optical fiber (7) is made of a material which has a higher melting point than the material of which the outer surface element (2) is made. [2] Arrangement according to claim 1, characterized by, that the light output surface (10) is at least partially enclosed by the outer surface element (2). [3] Arrangement according to claim 1 or 2, characterized by , that the light guide (7) is made of glass or a glass-like material and the outer surface element (2) is made of a plastic, in particular polycarbonate. [4] Arrangement according to any one of the preceding claims, characterized by , that the outer surface element (2) in the area where the light emission surface (10) is enclosed is transparent on the side facing out of the light guide (7) in the direction of light emission and is opaque on the opposite side. [5] Arrangement according to any one of the preceding claims, characterized by, that the arrangement further comprises at least one stabilizing element (11) which is at least partially enclosed by the outer surface element (2) or is integrally formed with the outer surface element (2) for the purpose of stabilizing the outer surface element (2). [6] Arrangement according to claim 5, characterized by , that the stabilizing element (11) is arranged adjacent to the light guide (7) enclosed by the outer surface element (2). [7] Arrangement according to claim 5 or 6, characterized by , that the optical fiber (7) enclosed by the outer surface element (2) and the stabilizing element (11) are elongated and that the longitudinal extent of the optical fiber (7) enclosed by the outer surface element (2) and the stabilizing element (11) is essentially parallel. [8] Method for manufacturing an external surface element (2) of a vehicle (1), wherein - a light guide (7) is formed with a light coupling surface (9) and a light coupling surface (10), - the light guide (7) is positioned in an injection mold and - the optical fiber (7) for forming the outer surface element (2) is overmolded with a material which has a lower melting point than the material from which the optical fiber (7) is made, - the outer surface element (2) is a window pane of the vehicle (1) or a flat body part, - the light source (4) is completely enclosed by the outer surface element (2) and the light guide (7) is cast into the outer surface element (2) at least section by section.

Images