Abstract:
A lighting element with a light emitting device preferably in the form of a light emitting diode, can be fitted in a light carrier. The lighting element has a light-transmissive lens body with a lens-shaped light entry surface and a light exit surface and the light exit surface is smaller than the light entry surface. A starry sky lighting configuration for example in an aircraft cabin, can be implemented with a plurality of such lighting elements.

Description:
BACKGROUND OF THE INVENTION  
     FIELD OF THE INVENTION  
       [0001]     The invention concerns a lighting element with a light emitting device, preferably a light emitting diode.  
         [0002]     Published, Non-Prosecuted German Patent Application DE 198 43 330 A1, corresponding to U.S. Pat. No. 6,203,180, discloses an aircraft cabin lighting configuration containing a plurality of light sources in point form which are mounted to or in the ceiling of the aircraft cabin. The light sources in point form have at least one light emitting diode which each irradiate their light directly into the interior of the aircraft cabin.  
         [0003]     Published, Non-Prosecuted German Patent Application DE 196 32 699 A1 discloses an optical fiber-based orientation display in which light is applied to optical fibers by at least two light emitting diodes and surface changes at the longitudinal side of the optical fiber result in an emission of light in the form of dashes, lines, points, symbols and the like for the purposes of a marking effect.  
         [0004]     Published, Non-Prosecuted German Patent Application DE 41 42 175 A1 describes a display device for aircraft, which has flat light guide elements, in the edge of which light emitting diodes are disposed in rows.  
         [0005]     The lighting elements in accordance with the above-outlined state of the art suffer from the disadvantage that the lighting area thereof is of a given minimum size.  
       SUMMARY OF THE INVENTION  
       [0006]     It is accordingly an object of the invention to provide a lighting element with a light emitting device which overcomes the above-mentioned disadvantages of the prior art devices of this general type, whose lighting area is particularly small.  
         [0007]     With the foregoing and other objects in view there is provided, in accordance with the invention, a lighting element for fitting into a light carrier. The lighting element contains a light emitting device and a light-transmissive lens body disposed downstream of the light emitting device. The light-transmissive lens body has a lens-shaped light entry surface and a light exit surface. The light exit surface is smaller than the lens-shaped light entry surface.  
         [0008]     The core of the invention provides that a lighting element of the general kind set forth has a light-transmissive lens body, preferably containing a transparent plastic material such as for example polycarbonate, and a lens-shaped light entry surface and a light exit surface. The light exit surface is of any small size whatever but at any event is smaller than the light entry surface.  
         [0009]     That configuration provides that the lighting surface of the lighting element can be of any small size whatever and in particular is also smaller than the light emitting device.  
         [0010]     Preferably the light entry surface of the lens body is shaped in such a way that the light that penetrates into the lens body from the light emitting device is deflected on to the light exit surface. That focusing effect provides that, in spite of its small extent, the lighting surface lights up sufficiently brightly.  
         [0011]     It can further be provided that the lighting element is fitted into the light carrier in such a way that the light exit surface of the lens body is flush with the surface of the light carrier, thereby providing that the light exit surface is almost invisible when the light emitting device is switched off.  
         [0012]     The light exit surface of the lens body can also be flat and/or roughened (‘ground’) and it can be circular, triangular or polygonal or also of any other shape. In addition the light emitting device should be disposed in the lighting element in such a way that a large part of the light emitted thereby impinges on the light entry surface of the lens body.  
         [0013]     In a development of the invention it can be provided that the light emitting device is fixed on and wired to a circuit board disposed in the lighting element, the light emitting device preferably being in the form of an SMD light emitting diode.  
         [0014]     Equally the lens body can be integrated into a lighting element body which contains the same material as the lens body and which accommodates the light emitting device. Preferably in that case the lens body and the lighting element body are in one piece.  
         [0015]     A configuration of the invention provides that the lighting element or the lighting element body has a guide, which is preferably provided with an abutment, for the light emitting device and/or for the circuit board and/or an opening for the feed of an electrical cable into the lighting element or the lighting element body.  
         [0016]     The light emitting device and/or the circuit board can be at least partially cast with silicone in the lighting element and thus can be releasably fixed therein.  
         [0017]     A further configuration of the invention provides that the lighting element or the lighting element body is held in a sleeve or socket that is fitted in the light carrier. In that case the light exit surface of the lens body, the end face of the sleeve and the surface of the light carrier are flush with each other in order to make the light exit surface virtually invisible when the lighting element is switched off.  
         [0018]     The lighting element or the sleeve can be glued in the light carrier. The ceiling or wall of an aircraft cabin can serve as the light carrier. The light emitting diode preferably emits white light and can be operated with uniform brightness, flashing or also flickering (lighting up more brightly—lighting up more darkly). The lighting element can be part of a starry sky lighting configuration.  
         [0019]     Other features which are considered as characteristic for the invention are set forth in the appended claims.  
         [0020]     Although the invention is illustrated and described herein as embodied in a lighting element with a light emitting device, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.  
         [0021]     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]      FIG. 1  is a diagrammatic, cross-sectional view of a first embodiment of an installed lighting element according to the invention;  
         [0023]      FIG. 2  is a diagrammatic, cross-sectional view of a second embodiment of the lighting element;  
         [0024]      FIG. 3  is a diagrammatic, cross-sectional view of a third embodiment of the lighting element;  
         [0025]      FIG. 4  is a diagrammatic, cross-sectional view of a fourth embodiment of the lighting element;  
         [0026]      FIG. 5A  is a diagrammatic, perspective view of a fifth embodiment of the lighting element; and  
         [0027]      FIG. 5B  is a diagrammatic, cross-sectional view taken along line VB-VB of the lighting element shown in  FIG. 5A . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]     Referring now to the figures of the drawing in detail and first, particularly, to  FIG. 1  thereof, there is shown a lighting element  2  installed in a ceiling panel  1  of an aircraft cabin in a suitable bore. The lighting element  2  includes a shaped plastic portion  3  having a bore  4  which in the upper region is of a large diameter, then adjoining it a medium diameter and, in the lower region which is towards an interior  5  of the aircraft cabin, a small diameter of about 1 mm. A light emitting diode  6  is fitted into the bore  4  of the shaped plastic body  3  in such a way that it is held by the transition from the region of the wide diameter into the region of the medium diameter of the bore  4  approximately at the middle of the shaped body  3  (steps  3 . 1  and  3 . 2 ). Beneath the light emitting diode  6 , fitted in the bore  4  is a light-transmissive lens body  7  formed of a transparent plastic material, having a light entry surface  8  which is curved upwardly in a lens-shaped configuration and a flat light exit surface  9 . The configuration of the light emitting diode  6  and the lens body  7  as well as the shape of the light entry surface  8  are such that the light emitted by the light emitting diode  6  (see beam path  10 ) is focused and deflected to the light exit surface  9  of the lens body  7 . The electrical connection of the light emitting diode  6  is made by the connecting leg portions  11  and  12  thereof and by way of cables  13  and  14  which are soldered or welded thereto.  
         [0029]     In the embodiment shown in  FIG. 2  the light emitting diode  6  is fixed and wired to a circuit board  15  with the portions  11  and  12  of the light emitting diode  6 . The circuit board  15  further carries inter alia an ESD protection diode  16  and is fitted into a guide  17  provided in the shaped plastic portion  3 . The guide  17  has an abutment  18  which, by virtue of defined positioning of the circuit board  15  in the lighting element  2 , provides that the light emitting diode  6  is disposed at the optimum spacing and in the optimum position with respect to the lens body  7 .  
         [0030]     In the embodiment shown in  FIG. 3  the circuit board  15  is not oriented parallel but perpendicularly to an optical axis. The light emitting diode  6  which is fixed and connected with its leg portions  11  and  12  to the circuit board  15  rests on the steps  3 . 1  and  3 . 2  in the bore  4  in the shaped body  3 . Latching hooks  19  and  20  which are formed in one piece on the shaped body  3  engage behind the circuit board  15  and thus prevent the circuit board  15  and the light emitting diode  6  from falling out of the lighting element  2 . Connecting cables  13  and  14  are taken past the latching hooks  19  and  20 .  
         [0031]     In the embodiment shown in  FIG. 4  the shaped body  3  and the lens body  7  are in one piece in the form of a lighting element body  21  that as a whole is formed of a light-transmissive plastic material. In addition the light emitting device  6  is in the form of a SMD light emitting diode  6 ′ which provides for lateral light emission. The connecting cables  13  and  14  are passed through bores or openings in the lighting element body  21 . The free internal space in the lighting element body  21  is sealed with vinegar-free silicone as a casting material  22 . At its upper end the circuit board  15  has a withdrawal hole  23  with which the circuit board  15  together with the light emitting diode  6 ′, the mounted electronic configuration  16  and the connecting cables  13 ,  14  as well as the casting material  22  can be withdrawn from the lighting element body  21 . That makes it easily possible to replace the light emitting diode  6 ′.  
         [0032]      FIG. 5A  shows a perspective view of the lighting element body  21  of a fifth embodiment of the lighting element  2 . It is possible to see in  FIG. 5A  the guide  17  for the circuit board  15  and a guide  24  for the SMD light emitting diode  6 ′. The guide  24 , like the guide  17 , has an abutment  25  for defined positioning of the light emitting diode  6 ′ with respect to the light entry surface  8  of the lighting element body  21 . It is also possible to see cable exit openings  26  and  27 .  
         [0033]      FIG. 5B  shows the complete lighting element  2  using the lighting element body  21  of  FIG. 5A  in cross-section taken along the line VB-VB.  
         [0034]     An electronic interference suppression or actuation configuration  16 ′ for the SMD lighting emitting diode  6 ′ is fixed on and connected to the circuit board  15 . The interior of the lighting element  2  or the lighting element body  21  is closed by a closure cap  28 . The lighting element body  21  is glued in a socket or sleeve  29  that is glued in a bore in the aircraft cabin ceiling  1 . In the central and upper parts the sleeve  29  has a wide bore for receiving the lighting element body  21  but in the lowermost part it has only a very narrow bore which only allows a light exit portion  30  of the lighting element body  21  to pass therethrough.  
         [0035]     The features set forth in the various embodiments can be combined together in any manner without thereby departing from the scope of the invention. Thus the lighting element can be disposed in flush relationship for example both with respect to the top side and also with respect to the underside of the ceiling panels of the aircraft cabin, wherein the light exit surface of the lighting element, the end face of the sleeve and the surface of the ceiling panels are preferably again disposed flush with each other. The light exit surface of the lighting element can be flat or also of a roughened configuration. The latter provides that the light issuing from the lighting element is scattered in various directions, whereby the light point produced by the light exit surface is visible from all directions (therefore even at very shallow viewing angles) from the interior  5  of the aircraft cabin.  
         [0036]     This application claims the priority, under 35 U.S.C. § 119, of German patent application No. 103 31 075.4, filed Jul. 9, 2003; the entire disclosure of the prior application is herewith incorporated by reference.