Description

This invention concerns a lighting device, in particular a lighting device for a vehicle, according to the preamble of claim 1.

A lighting device of the above type is known from DE 10 2014 117 883 A1. The light ing device described therein may, for example, be designed as a headlamp of a vehi cle and comprises, for example, a light source designed as a light-emitting diode (LED) or as a laser diode. The lighting device also includes a hologram through which the light from the light source passes. The hologram is especially designed as a pho topolymer in the form of a flexible foil. The hologram may produce directional light so that a light distribution corresponding to a passing beam and/or a driving beam can be produced in front of the vehicle.

The problem underlying this invention is the creation of a lighting device of the type mentioned above, which can be better adapted to different requirements, in particular as regards the positioning or installation space of the lighting device.

According to the invention, this is achieved by a lighting device of the type mentioned above with the characteristic features of claim 1. The subclaims concern preferred forms of the invention.

In accordance with claim 1 the lighting device shall comprise a second flexible foil in which the at least one light source is integrated or on which the at least one light source is arranged. This allows the entire lighting device to be made flexible. Such a design makes it easy to adapt the lighting device to the local requirements of the vehi cle, for example. In particular, it is possible, for example, to apply the lighting device to curved surfaces. In addition, a lighting device with two foils for generating and shaping the light can be made very flat, so that the space requirements of the lighting device are low. It may be provided that the lighting device comprises several light sources integrated into the second foil or arranged on the second foil. The number of light sources can be adapted to the function of the lighting device. For example, the at least one light source can be designed as a light-emitting diode.

It is possible that contact elements for making electrical contact with the at least one light source are arranged on the second foil, in particular laterally on the second foil. This means that even a very flat lighting device can be reliably connected.

It may be provided that the first foil and the second foil are arranged parallel to one an other, in particular the two foils being spaced apart from one another. Preferably, the lighting device comprises a spacer arranged between the first and second foils, the spacer in particular also being flexible. The spacer can, for example, be designed as a frame or as a transparent plastic component. The spacer can have a suitable thick ness to optimize the distance between the two foils. Furthermore, the flexibility of the spacer ensures that the entire lighting device can be designed to be flexible.

It is possible for the lighting device to comprise means for dissipating the heat gener ated by the at least one light source, the means being arranged in particular on the side of the second foil facing away from the first foil. The means for dissipating the heat generated by the at least one light source may, for example, be in the form of a heat-conducting paste. Despite the fact that the lighting device may be very flat, the heat generated by the light sources can be dissipated well in this way.

It may be provided that the lighting device comprises adhesive means enabling the lighting device to be fastened to a surface, the adhesive means being arranged in par ticular on the side of the second foil facing away from the first foil. The adhesives can be used to glue the lighting device to a curved surface such as the engine hood of a vehicle. It is possible that the lighting device is waterproof. This allows the lighting device to be installed in an exterior space, such as the outside of a motor vehicle, without allowing water to enter the possibly sensitive electronics of the lighting device.

It may be provided that the first foil influences the light passing therethrough in such a way that a light distribution is generated which corresponds to the application purpose of the lighting device. For example, when the lighting device is designed as a head lamp of a motor vehicle, the first foil may be able to produce a suitable light distribu tion.

In particular, the first foil may comprise a hologram or be formed as a hologram, the hologram being in particular a replica hologram of a computer-generated master holo gram. A suitable hologram design can, for example, generate a light distribution that corresponds to that of a passing beam and/or a driving beam.

The invention is explained in more detail below on the basis of the attached drawings. And shows

Fig. 1 an exploded view of a lighting device according to the invention in a side view;

Fig. 2 a side view of the lighting device according to Fig. 1 when assembled;

Fig. 3 a perspective explosion view of the lighting device according to Fig. 1 ;

Fig. 4 a perspective view of the lighting device according to Fig. 1 when assem bled.

In the figures, identical and functionally identical parts are provided with the same ref erence signs. The figures depict a lighting device corresponding to the invention, which can be used, for example, as a headlamp of a motor vehicle. The lighting device comprises a first flexible foil 1 , a second flexible foil 2 and a spacer 3, which is also flexible, arranged between the first foil 1 and the second foil 2.

A plurality of light sources 4 formed as light emitting diodes are arranged on the upper side of the second foil 2 as shown in Fig. 1 and Fig. 3. During operation of the lighting device, the light emitted by the light-emitting diodes propagates upwards in Fig. 1 to Fig. 4 or in the direction of the first foil 1.

Contact elements 5 for the electrical contacting of the light sources 4 are arranged on at least one end face of the second foil 2. The contact elements 5 are connected to the individual light sources 4 by means of connecting elements such as conductor paths which are not illustrated.

Only schematically indicated means 6 for dissipating the heat generated by the light sources 4 are arranged on the lower side of the second foil 2 shown in Figs. 1 to 4 or on the side of the second foil 2 facing away from the light sources 4. The means 6 for dissipating the heat generated by the light sources 4 are designed as heat conducting paste.

On the lower side of the second foil 2 shown in Figs. 1 to 4, or on the side of the sec ond foil 2 facing away from the light sources 4, there are also adhesives 7, which ena ble the lighting device to be attached to a surface. The adhesives 7, for example, can be designed as a double-sided adhesive tape applied from below to the surface of the second foil 2, which surrounds the heat-conducting paste.

The first foil 1 comprises a hologram or is designed as a hologram, whereby the holo gram is in particular a replica hologram of a computer-generated master hologram.

The hologram can influence the light emitted by light sources 4 in such a way as to generate a light distribution appropriate to the application purpose of the lighting de vice. In particular, a typical light distribution of a headlamp can be generated. The first foil 1 and the second foil 2 are parallel and spaced from each other. It is pos sible that the foils are not arranged parallel to each other. The spacer 3, which is ar ranged between the two foils 1 , 2, can in particular consist of silicone. The spacer 3 has a suitable thickness to optimize the distance between the two foils 1 , 2. At a suita ble distance, the first foil 1 can be optimally illuminated by the light of the light sources 4 so that the desired light distribution is achieved.

The spacer 3 provided in the example shown is designed as a circumferential frame with a large central opening 8 for the light to pass through. However, it is also possible to use a plate-shaped, transparent plastic part instead of a frame, through which the light from light sources 4 can pass.

Fig. 2 and Fig. 4 show the lighting device when assembled. Because both foils 1 , 2 and spacer 3 are flexible, the lighting device as a whole is also flexible. It can there fore be adapted to objects with a curved surface. For example, the lighting device can be attached to a curved engine hood of a motor vehicle.

The spacer 3 and the two foils 1 , 2 can be connected to each other in such a way that the lighting device is watertight.

List of reference signs

1 first foil

2 second foil

3 spacer

4 light source

5 contact element

6 means for dissipating heat

7 adhesive means

8 opening in a spacer in the form of a frame