Patent ID: 6249090
Filing Date: 2001-06-19
Classification: H01J

Abstract:
An electrodeless fluorescent RF lamp and fixture comprising:a bulbous lamp envelope and a reentrant cavity disposed in said envelope, a rare gas and vaporizable metal fill in said envelope and a phosphor coating on the interior thereof for generation of visible light;a lamp base disposed outside said envelope and said fixture being attached to said lamp base;a cylinder formed of a light thermally-conductive metal disposed in said reentrant cavity, said cylinder being attached to said lamp base;an induction coil and radio frequency excitation generating means associated with said coil for the generation of a plasma to produce radiation to excite said phosphor coating, said coil and said means being situated outside said envelope and fitted within said cavity and within said cylinder, at least a major portion of said coil having a pitch between about 1 and 10 mm and a wire diameter between about 0.5 and 3.0 mm, said coil having a top portion, a bottom portion and a middle portion, the pitch of the turns of said coil in said top and bottom portions being less than the pitch of the turns in said middle portion.