Abstract:
An arrangement for light emission has at least one LED light-emitting means ( 110 ) in an elongate arrangement, a support element ( 120 ), which supports the LED light-emitting means ( 110 ) and a light emission element ( 130 ) which can be connected to the support element ( 120 ). The light emission element ( 130 ) is designed to modify the light emission characteristic of the LED light-emitting means ( 110 ) to give the light emission characteristic of at least one fluorescent tube.

Description:
The subject matter of the application is an arrangement for light-emission having LED illuminants in an elongate arrangement, a carrier element which carries the LED illuminants, and a light-radiating element which can be connected to the carrier element. Further subject matter of the application is a luminaire. 
     BACKGROUND OF THE INVENTION 
     The optical capacity of LED light sources has undergone a development, making their use appear of interest for general lighting purposes. LED light sources are distinguished by their efficiency and, whilst provided the operating conditions are observed, by particular reliability. Their light-radiation characteristic as well as the operating conditions to be observed do, however, basically differ from those of conventional illuminants, such as, for example, incandescent bulbs, fluorescent tubes or gas-discharge lamps, so that it appears that existing luminaire constructions can only be retrofitted at considerable expense. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an arrangement for light-emission which optimizes the outlay on retrofitting existing luminaire constructions. 
     This object is achieved with the features of the independent claims. Further developments of the invention constitute subject matter of the dependent claims. An arrangement for light-emission in accordance with the invention has at least one LED illuminant in an elongate arrangement, a carrier element which carries the LED illuminant, and a light-radiating element which can be connected to the carrier element. The light-radiating element is formed to convert the light-radiation characteristic of the LED illuminant to the light-radiation characteristic of at least one fluorescent tube. Simple replacement of conventional fluorescent tubes by LEDs is thus possible without having to effect a complete new construction. 
     Basing considerations on the thought that the light-radiation characteristic and the position of installation of LEDs and conventional light sources differ for reasons of observance of the operating conditions for the respective illuminants, an arrangement is proposed for light-emission that has LED illuminants in an elongate arrangement, a carrier element which carries the LED illuminants, and a light-radiating element which can be connected to the carrier element. 
     It is provided in this connection that the light-radiating element radiates incident radiation of the LED illuminants over a light-emission area so that adaptation of the light-radiation characteristic can be carried out by way of the form of the light-radiating element. An elongate arrangement of the LED illuminants assists the approximation to the light-radiation characteristic of a fluorescent tube. A plurality of LEDs that admittedly preferably belong to the same type class can be used as illuminants, although the invention is not limited thereto in the least. For example, LEDs with different power characteristics or colour radiation can be used. 
     The light-radiating element is preferably formed to simulate the light-radiation characteristic of an arrangement of fluorescent tubes. In a further development of the invention it is provided that the light-radiating element is formed as a diffuser. This renders possible, starting from the surface, uniform illumination of larger areas. 
     Simulation of the light-radiation characteristic of an arrangement of a plurality of fluorescent tubes is also possible. Typically, the close arrangement of two fluorescent tubes side by side is replaced thus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described by way of example in the following with reference to the drawings in which an advantageous exemplary embodiment of the invention is presented and in which: 
         FIG. 1  shows an exemplary embodiment of the arrangement in accordance with the invention and  FIG. 3  shows the embodiment of  FIG. 1  as an elongate arrangement; and 
         FIG. 2  shows a detailed view of the exemplary embodiment of the arrangement in accordance with the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the first instance, the general structure of the luminaire in accordance with the invention is explained with reference to  FIG. 1 . Subsequently, the precise technical structure and the mode of functioning of the luminaire in accordance with the invention and the arrangement for light-emission in accordance with the invention are presented with reference to  FIG. 2 . Identical elements have in part not been repeatedly presented and described in figures that are similar. 
       FIG. 1  shows an exemplary embodiment of a luminaire  10  in accordance with the invention in a sectional representation. The luminaire  10  in accordance with the invention in this case contains a housing  20 , a reflector  30  and an arrangement for light-emission  100 . With its closed side, the upper side in the drawing, the housing  20  can in this case be secured to a surface, for example a ceiling. The light-emission is effected through the arrangement for light-emission  100  in the opposite direction. The reflector  30  then reflects a portion of the luminous power emitted by the arrangement for light-emission  100 . 
     The reflector  30  is in this case set up with a curved form, in particular a parabolic form. Uniform illumination of a region that is controllable in a targeted manner is thus achieved. The reflector  30  in this case ends so as to be flush with the housing  20  of the luminaire  10 . The reflector  30  is provided with a focal point in the sectional representation. In three-dimensional reality, this is not a focal point, but a focal line. The focal point or line largely corresponds, at least in sections  165 , with the outer surface of the light-radiating element  130 , or rather sections  165  of the limiting face or outer surface  160  of the light-radiating element  130  correspond with the focal point or line. Optimum distribution of the light that is radiated by the light-radiating element  130  through the reflector  30  is thus achieved. 
     The arrangement for light-emission  100 , which is shown in greater detail in  FIG. 2 , contains a carrier element  120 , an LED illuminant  110  and a light-radiating element  130 . The carrier element  120  is reversibly connectable to an illuminant-carrier, in that the illuminant-carrier is an LED printed circuit board  140  shown in  FIG. 2 , and in that the carrier element  120  and the illuminant-carrier are preferably connectable and releasable without a tool. The carrier element  120  is in this case connected to the housing  20  of the luminaire  10 . The carrier element  120  carries, furthermore, the LED illuminant  110 . Alternatively, a plurality of LED illuminants  110  can also be secured to the carrier element  120 . The LED illuminant  110  is preferably reversibly connected to the carrier element  120  and can be connected or separated without the use of a tool. The LED illuminant  110  is arranged in such a way that the light-radiation is effected in the direction of the open side of the housing. Arranged between the LED illuminant  110  and the open side of the housing there is, furthermore, the light-radiating element  130 . In this case, light-radiating element  130  is connected to the carrier element  120  and held by it at connections  132  and  134 . Advantageously, this connection is reversible and can be effected and released without the use of a tool. Instead of being connected merely to the housing  20 , the carrier element  120  can complete the surface of the housing  20  that is interrupted by an opening. It is thus possible to make savings in terms of material for the housing. 
     The reflector  30  is likewise connected to the carrier element  120 . In the case of a conventional luminaire, one or more fluorescent tubes would be located at the focal point or focal line of the reflector  30  along sections  165 , when more than one fluorescent tubes are present. These would be arranged perpendicularly with respect to the sectional plane of the drawings. The light-radiating element  130  is formed here in such a way that its outer form largely corresponds to the contour of the fluorescent tube or fluorescent tubes in a conventional luminaire. The light-radiating element  130  thus converts the light-radiation characteristic of the LED illuminant  110  to the light-radiation characteristic of at least one fluorescent tube. 
     For this, the light-radiating element  130  is formed as a diffuser. In other words, hard light is turned into soft diffused light. Thus a virtual light source is generated at the position of the outer surface of the light-radiating element  130 . This virtual light source has the radiation characteristic of one or more fluorescent tubes. Individual LED illuminants are no longer discernible. Advantageously, the light-radiating element  130  is produced from diffuse plastics material. 
     The light-radiating element  130  in this connection is a profiled body with a substantially trapezoidal cross section. It is aligned in this case along the replaced fluorescent tube  150  and thus along the LED illuminant  110 . The light-radiating element  130  then extends over the whole length of the LED illuminants  110 . The limiting faces or outer surface  160  of the light-radiating element  130  in sections  165  correspond substantially with a surface form of one or more fluorescent tubes  150  that can be arranged between the carrier element  120  and the light-radiating element  130 , as best shown in  FIG. 2 . 
     The reflector  30  projects into the region of the light-radiating element  130 . In other words, the reflector  30  and the light-radiating element  130  overlap in part. The reflector  30  has a first light-radiation characteristic outside the light-radiating element  130 . In the region inside the light-radiating element  130 , the reflector has a second light-radiation characteristic. As a result, the whole light-radiation characteristic of the luminaire  10  can be adjusted further. 
     Advantageously, moreover, the surface of the carrier element  120  that is directed in the direction of the light-radiation is provided with a coating of high reflectivity. A further increase in the degree of efficiency of the luminaire can thus be attained. 
     The luminaire  10  is provided, furthermore, with a light-exit opening. The light-exit opening is in this case advantageously provided with a cover  40  which is shown in  FIG. 1 . The cover  40  is divided into a plurality of sections. In the vicinity of the light-radiating element  130  the cover is provided with a first light-radiation characteristic  42 . In the region close to the edge of the luminaire  10 , that is, remote from the light-radiating element  130 , the cover  40  is provided with a second light-radiation characteristic  44 . Thus further fine adjustment of the light quality can be effected in the various regions that are to be illuminated. For example, diffuse, very uniform illumination is possible in the region of the light-radiating element  130  directly in the direction of the light-exit opening of the luminaire, whilst in the lateral region, that is, to the side of the direct direction of radiation, illumination that is less diffuse is achieved with at the same time a higher degree of efficiency on account of lower losses as a result of the diffuser. 
     The invention is not limited to the exemplary embodiment shown. Profiles of the light-radiating element that deviate therefrom are also conceivable. Use without a reflector is within the inventive idea. All of the features described above or features shown in the figures can be combined with each other advantageously in any way within the scope of the invention.