Patent ID: 7385353
Filing Date: 2008-06-10
Classification: H01J

Abstract:
1. A low-pressure discharge lamp having an essentially tubular discharge vessel ( 1 ) which consists of glass and is sealed in a gas-tight manner at the ends, having a filling comprising a noble gas mixture and possibly mercury and possibly having a fluorescent coating on the inner wall of the discharge vessel ( 1 ), in each case two power supply lines ( 3 , 4 ) being fused into the two ends of the discharge vessel ( 1 ) in a gas-tight manner and running essentially parallel to the longitudinal axis of the discharge vessel ( 1 ) in this section, a filament electrode ( 5 ), which runs essentially transversely with respect to the longitudinal axis of the discharge vessel, being fixed at the inner end of each of said two power supply lines ( 3 , 4 ), characterized in that, in order to increase the switching strength of the lamp during coldstarting operation, at least one further electrode ( 7 , 8 ) consisting of a conductive material is arranged in the region between the filament electrode ( 5 ) and the adjoining end of the discharge vessel ( 1 ), one end of this further electrode ( 7 , 8 ) being electrically connected to one of the two power supply lines ( 3 , 4 ), the free end of the further electrode ( 7 , 8 ) has a distance of (0.2−1)×R inner tube from the axis of the filament electrode ( 5 ), R inner tube being the inner radius of the discharge vessel ( 1 ) in this section of the discharge vessel ( 1 ).