Patent ID: 7952113
Filing Date: 2011-05-31
Classification: F21K,F21V,F21Y,H05K

Abstract:
1. A flat lighting device comprising light-emitting lighting elements arranged on a carrier, which are connected to current supply and current discharge lines to supply current, the carrier has the form of a metallic sheet ( 2 ), which is covered with an insulating layer ( 3 ), on which series connections of one lighting element ( 1 ) and one surface series resistor ( 5 ) are arranged between the current supply and current discharge lines ( 4 ′), the-one lighting element ( 1 ) and the one surface series resistor ( 5 ) of a series connection as well as the series connections and the current supply and current discharge lines ( 4 ′) are connected to one another by conductor paths ( 4 ), a plurality of series connections are arranged next to one another between the current supply and current discharge lines ( 4 ′), a plurality of branches, which comprise, one behind the other, a plurality of series connections of a lighting element ( 1 ) and a surface series resistor ( 5 ) in each case, are arranged between the current supply and current discharge lines ( 4 ′), potential equalization lines ( 4 ″) are provided, which in each case connect to one another the points ( 16 ), arranged next to one another, of the conductor paths ( 4 ) of the branches, which are arranged between series connections of a lighting element ( 1 ) and a surface series resistor ( 5 ), in each case, the metallic sheet ( 2 ) is an aluminum sheet, the aluminum sheet has a thickness of about 70 μm, the insulating layer ( 2 ) is formed by a paper web laminated on to the metallic sheet ( 2 ), the conductor paths ( 4 ) the current supply and current discharge lines ( 4 ′) are printed onto the surface of the insulation layer ( 3 ) by a gravure printing method, the conductor paths, the current supply and current discharge lines ( 4 ′) consist of a conductive dye, the conductive dye is a silver conductive dye, the surface series resistors ( 5 ) are printed onto the surface of the insulating layer ( 3 ) by the gravure printing method, the surface series resistors ( 5 ) and the conductor paths ( 4 ) are printed on so as to overlap, the surface series resistors consist of a further conductive dye, the further conductive dye is a graphite conductive dye, the connections ( 7 ) of the lighting elements ( 1 ) are in each case bonded to connection contact faces ( 7 ) which are arranged on conductor paths ( 4 ) with a conductive adhesive, or soldered, the connection contact faces ( 7 ) are printed on together with the corresponding conductor paths ( 4 ) by a gravure printing method, the lighting elements ( 1 ) are light-emitting diodes, a body part ( 9 ) of the lighting element ( 1 ) is seated on a contact connection face ( 8 ) located there below, so that good heat dissipation takes place from the body part ( 9 ) to the metallic sheet ( 2 ), and a stabilizing coating ( 6 ) is arranged on the lighting elements ( 1 ) for stabilization and for mechanical fixing thereof and also covers the regions of the connections ( 7 ) of the lighting elements ( 1 ) and of connection contact faces ( 8 ), but leaves the light-emitting front side of the lighting elements ( 1 ) free.