Abstract:
A lighting device is disclosed that is configured for mounting in or on a motor vehicle. The lighting device comprises a light guiding element and a light source. The light guiding element has a light entry face and a light exit face. A depth of the lighting device perpendicular to the light exit face corresponds essentially fully to the depth of the light guiding element.

Description:
BACKGROUND 
       [0001]    The invention relates to a lighting device, particularly a lamp, particularly for installation in or on a motor vehicle. 
         [0002]    In automobile construction, lamps are often used for different series from the same manufacturer and meet different functional requirements, for example when used as a cosmetic mirror or for illuminating storage compartments or a footwell in the vehicle. 
         [0003]    Individual examples of such lamps are known from the documents DE 10 2005 037 320 B3, DE 20 2006 003 757 U1 and DE 10 2005 024 838 A1. 
         [0004]    It has been found to be disadvantageous in practice that the structure for holding a known lamp needs to have a comparatively large physical depth of several centimeters and, furthermore, the removal of the heat produced by the lamp requires extensive refinement of the structure, which takes up further installation space. As a measure for adaptation to suit the reduced installation space, it has been customary to date to reduce the usable depth of other vehicle components arranged adjacent to the lamp, such as map cases. 
         [0005]    A further drawback of the prior art is that appropriate mechanisms need to be provided which allow replacement of the light source for the lamp, for example an incandescent lamp. 
         [0006]    The object of the invention is thus to propose remedial measures for the problem described above. 
         [0007]    The object is achieved by a lighting device having a light guiding element and a light source for mounting in or on a motor vehicle, wherein the light guiding element has a light entry face, wherein the light guiding element has a light exit face, and wherein the depth of the lighting device perpendicular to the light exit face corresponds essentially fully to the depth of the light guiding element. This allows the lighting device to be designed to be particularly shallow (i.e. of little physical depth), since only the depth of the light guiding element is provided as the depth of the entire lighting device. Further installation space—for example for a further housing or a light bulb holder or the like—is not required. 
       SUMMARY 
       [0008]    One important feature of the invention is that for different fields of application, a few of which have been cited by way of example above, a light emitting diode LED is used as a light source which is preferably of physically shallow design. In the text which follows, the term “light emitting diode” (or LED) and the term “light source” are therefore used largely synonymously. 
         [0009]    A further important feature of the invention is that the lighting device has the light guiding element as a carrier. An example of a suitable carrier or light guiding element is a carrier which interacts with the LED, is completely or partially transparent and is designed and/or in a physical arrangement relative to the light source such that the light produced by the LED is guided in a defined direction (or a defined angular range of 30° aperture or else 45° aperture, for example) by the carrier (or the light guiding element) and is emitted (particularly for the purpose of illuminating a particular region of the lighting device which needs to be lit). According to the invention, it is particularly preferred in this context for the light guiding element to be a light guiding body or for the light guiding element to have a reflector. If the light guiding element is a light guiding body, the light is guided essentially over its entire path by the material of the light guiding element. If the light guiding element has a reflector, the light is not guided over its entire path by the material of the light guiding element but rather is guided by a (liquid-filled, gas-filled or else (at least partially) evacuated) interior, for example. 
         [0010]    In one refinement of the invention, the carrier or the light guiding element is produced partially or completely from plastic. 
         [0011]    In accordance with one embodiment of the invention, the LED is embedded on a rigid or flexible conductor in a manner which is known per se—when considered on its own—and is integrated in or connected to the carrier (or light guiding element). 
         [0012]    In accordance with another embodiment of the invention, the LED is insert molded directly during the production or design of the plastic carrier (or light guiding element). 
         [0013]    According to the invention, such measures result in the opportunity to give the lighting device according to the invention a particularly physically shallow design, i.e. to design the extent of the lighting device in a direction perpendicular to the light exit face to be as small as possible. 
         [0014]    According to the invention, the lighting device according to the invention is preferably of such physically shallow design that the depth of the lighting device perpendicular to the light exit face is less than 10 mm, preferably less than 8 mm, particularly preferably less than 5 mm. This has the great advantage that the lighting device can be of very space-saving design and hence is universally usable (for example in vehicle construction). 
         [0015]    The fastening for the lighting device according to the invention can be used, particularly at the same time, as a cable pushing. 
         [0016]    According to the invention, the implementation of the light guiding element as a carrier allows all the colors of the light produced by the lighting device according to the invention to be shown. 
         [0017]    According to the invention, it is particularly preferred for the light entry face to be provided essentially perpendicular to the light exit face. According to the invention, this advantageously allows the lighting device to be of shallow design because the light source can be positioned on the light guiding element at the side and it is possible to avoid arranging the light source on that side (back) of the light guiding element which is averted from the light exit face (of the lighting device), which further reduces the possible physical depth which can be attained. In order to implement such lateral connection of the light source, it also preferred for the lighting device to have a back and also lateral faces averted from the light exit face, wherein the lighting device also has electrical connection means for electrical connection of the lighting device in the region of the lateral faces. 
         [0018]    It is also preferred, according to the invention, for the light guiding element to have a connecting element for mounting the lighting device. By way of example, such a connecting element is a connecting clip or a plurality of connecting clips which is/are used for clipping the lighting device on a motor vehicle component, for example a roof liner or a sun visor or a storage compartment or a license plate lighting holder. In particular, such a motor vehicle component has a recess or an opening such that the lighting device can be put through the opening and fastened by means of the connecting element. 
         [0019]    For the purpose of advantageously implementing particularly good uniform light distribution in the region of the light exit face, the lighting device preferably has at least one angular face on the back. By way of example, an appropriate material design for the light guide and particularly appropriate patterning on the back of the light guide allow the implementation of light exit, adapted to suit the lighting requirements, from the light exit face, for example by virtue of prism-like structural elements on the back of the light guiding element or the like. 
     
    
     
       DRAWINGS 
         [0020]    An embodiment of the invention which should be regarded as purely exemplary is described in a little more detail below with reference to the appended drawings, in which: 
           [0021]      FIG. 1  shows a section through a lighting device designed according to the invention, in a schematic illustration, 
           [0022]      FIG. 2  shows a plan view of a plastic carrier as a light guiding element in the lighting device designed according to the invention, 
           [0023]      FIGS. 3 and 5  show a section through a lighting device designed according to the invention based on one variant, in a schematic illustration, 
           [0024]      FIG. 4  shows a plan view of a plastic carrier as a light guiding element in the lighting device designed according to the invention based on the variant shown in  FIG. 3 , 
           [0025]      FIGS. 6 to 10  show sections through lighting devices designed according to the invention in a schematic illustration based on further variants of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    The lighting device B designed according to the invention which is shown in a schematic sectional illustration in  FIGS. 1 ,  3  and  5  comprises a plastic carrier  1  (or a light guiding element  1 ) and a light source  2 , particularly in the form of an LED  2  injection molded into the plastic carrier  1 . Situated in physical proximity to the LED  2  are a plurality of connecting clips  3 , arranged above the LED  2 , as connecting element  3  (or a plurality of connecting elements  3 ). In addition, an integrated connector  4  arranged at the side of the LED  2  is visible as connection means  4  (referred to in English literature as an “integrated connector”). 
         [0027]    Both in the embodiment shown in  FIG. 1  and on the basis of the variant shown in  FIG. 3  or  5 , the plastic carrier  1  (or the light guiding element  1 ) is designed and in a relative physical arrangement, particularly in the region of its back and relative to the LED  2 , such that the light produced by the LED  2  is guided through the plastic carrier  1  or the light guiding element  1  upwards in the direction of a (light) exit face  10  which bounds the plastic carrier  1  at the top. In particular, provision is made, for example using at least one prism and/or at least one lens, for the light to exit the plastic carrier  1  or light guiding element  1  from the exit face  10  in scattered fashion. 
         [0028]    In accordance with the variant embodiment shown in  FIG. 1 , the plastic carrier  1  is provided with a rib structure  5  in the example, particularly in the region of its back. 
         [0029]    In accordance with the variant embodiment shown in  FIGS. 3 and 5 , the plastic carrier  1  is provided from transparent material, for example, which has a plurality of microscatter centers embedded in it. These scatter centers are distributed throughout the material and cater for the decoupling of the light. Special further measures are not required in this variant embodiment. This avoids the construction complexity and at the same time increases the design freedom. 
         [0030]    Both in accordance with the variant embodiment shown in  FIG. 1  and in accordance with that shown in  FIGS. 3 and 5 , the LED  2  or light source  2  is bounded at the top by a first upper face  20  and at the bottom by a first lower face  21 , the latter being arranged parallel both to the upper face  20  and to the (light) exit face  10 . Two lateral faces  22 ,  22 ′ which are arranged parallel to one another and at right angles to the lower face  21  or upper face  20  bound the LED  2  on both sides. The LED  2  has a thickness which is less than 10 mm, which means that the LED  2  is of particularly shallow design. In accordance with the invention, the light produced by the light source  2  or the LED  2  enters the light guiding element  1  particularly from one of the lateral faces  22 ,  22 ′. A face of the light guiding element  1  which is opposite one of these lateral faces  22 ,  22 ′, particularly the face which is opposite that lateral face  22  which points toward the main region of the light guiding element  1 , is therefore also referred to as a light entry face  2 ′ (into the light guiding element  1 ). 
         [0031]    The plastic carrier  1  has a second lower face  14  (or back) arranged parallel to the exit face  10 . In the variant embodiment shown in  FIG. 1 , a slanted angular face  11  extends from the second lower face  14  to a step face  12 , which is likewise arranged parallel to the exit face  10 . The figure shows an exemplary embodiment in which the angular face  11  makes up less than half the extent of the light guiding element  1 , and the second lower face  14  together with the step face  12  make up more than half of this extent. According to the invention, a further variant may also have provision for the step face  12  to comprise more than half this extent (and then to have a shallower profile) and for the second lower face  14  together with the step face  12  to make up less than half this extent. In accordance with the variant embodiment shown in  FIGS. 3 and 5 , the second lower face  14  (or back) is produced without an angular face  11  or step and without an offset step face  12 . On the contrary, in a variant shown in  FIGS. 3 and 5 , the second lower face  14  extends more or less over the entire front or light-emitting exit face  10  of the light guiding element  1 . 
         [0032]    The distance between the second lower face  14  and the exit face  10  is approximately 5 mm, for example. 
         [0033]      FIGS. 2 and 4  each show a plan view of the plastic carrier  1 , which has a length of 60 mm and a width of 25 mm, for example. 
         [0034]    Along the perimeter of the light guiding element  1 , the light guiding element  1  is connected (both in accordance with the variant shown in  FIGS. 1 and 2  and as shown in  FIGS. 3 ,  4  and  5 ) to a motor vehicle component, particularly an interior component  30 , particularly by means of the connecting element  3  or the plurality of connecting elements  3 . To this end, the front of the light guiding element  1  has (along the periphery of the light guiding element  1 ) an overhang which conceals or covers the connecting region relative to the interior component  30  or relative to the motor vehicle component. The material thickness of this overhang perpendicular to the exit face  10  is 1.5 mm, for example. 
         [0035]      FIGS. 6 to 10  show sections through lighting devices B designed according to the invention in a schematic illustration based on further variants of the present invention. In this context,  FIG. 6  shows a variant of the lighting device B in which the decoupling of light (particularly on the back or on the second lower face  14 ) is produced by means of rough patterning  15  of the second lower face  14  or of the light guiding element  1  in the region of the second lower face  14 . In this case, the light guiding element  1  is provided particularly as a transparent light guide. 
         [0036]      FIG. 7  shows a variant of the lighting device B in which the decoupling of light (particularly on the back or on the second lower face  14 ) is produced by means of a geometric structure  16  at the second lower face  14  or of the light guiding element  1  in the region of the second lower face  14 , particularly in the form of prisms. In this case, the light guiding element  1  is provided particularly as a transparent light guide. 
         [0037]      FIG. 8  shows a variant of the lighting device B in which the decoupling of light is implemented by means of a plurality or a multiplicity of scatter centers or microscatter centers, wherein the microscatter centers are provided so as to be distributed particularly over the entire volume of the light guiding element  1 . In this case, the light guiding element  1  is provided particularly as a transparent light guide. 
         [0038]      FIG. 9  shows a variant of the lighting device B in which the decoupling of light (particularly on the back or on the second lower face  14 ) is produced by means of rough patterning  15  of the second lower face  14  or of the light guiding element  1  in the region of the second lower face  14 . In this case, the light guiding element  1  is designed particularly as a reflector with a diffuser or a diffusing panel in the region of the exit face  10 . 
         [0039]      FIG. 10  shows a variant of the lighting device B in which the decoupling of light (particularly on the back or on the second lower face  14 ) is produced by means of a geometric structure  16  of the light guiding element  1  in the region of the second lower face  14 , particularly in the form of prisms. In this case, the light guiding element  1  is designed particularly as a reflector with a diffuser or a diffusing panel in the region of the exit face  10 . 
         [0040]    The lighting device B according to the invention can, in principle, be used for all manner of lighting purposes instead of conventional universal lamps. 
         [0041]    The text below presents a small selection of possible opportunities for use of the lighting device according to the invention. 
         [0042]    Motor vehicle interior:
       Lighting devices according to the invention which are arranged in the region of the roof liner can be used for the following purposes: makeup mirror lighting, entrance lamp, illumination of the rear region, particularly in the case of vehicles of “van” type.   Lighting devices according to the invention which are arranged in the region of a motor vehicle door can be used for the following purposes: puddle light, warning lamp, map case illumination.   Lighting devices according to the invention which are arranged in the region of a motor vehicle seat can be used for the following purposes: footwell illumination, reading light.   Lighting devices according to the invention which are arranged in the region of a motor vehicle dashboard can be used for the following purposes: glove compartment illumination, storage space illumination, footwell illumination.       
 
         [0047]    Motor vehicle exterior:
       Lighting devices according to the invention can be used for the following purposes: license plate lighting, direction of travel indicator, warning lamps, reversing lamps.       
 
       LIST OF REFERENCE SYMBOLS 
       [0000]    
       
         
           
               1  Light guiding element/plastic carrier 
               2  Light source/LED light-emitting diode 
               2 ′ Light entry face 
               3  Connecting element/connecting clips 
               4  Electrical connection means/integrated connector 
               5  Rib structure 
               10  Light exit face/exit face 
               11  Angular face 
               12  Step face 
               14  Second lower face 
               15  Rough patterning 
               16  Geometric structure 
               20  First upper face of the light source 
               21  First lower face of the light source 
               22 ,  22 ′ Lateral faces of the light source 
             B Lighting device 
               30  Interior component