Fluorescent tube ignitor

Claim 1

An ignitor circuit for igniting a plurality of fluorescent tubes, each tube having external walls, a first and a second end and first and second filaments, each disposed within said tube adjacent the first and second end respectively, comprising: a first plurality of filament electrodes connected to the first filament of each tube and a second plurality of filament electrodes connected to the second filament; said second plurality of filaments being connected in parallel; preheater means for pre-heating the filaments of each tube, said preheater including first low voltage means for providing a plurality of first low voltage sources connected individually to each of said first plurality of filament electrodes at the first end of each tube, said preheater means further including second low voltage means for providing a single second low voltage to said parallel connected second plurality of filament electrodes at the second end of each tube; a plurality of high voltage ignites for supplying a specific high voltage individually to the filaments of each tube to selectively illuminate each tube, said high voltage means having a plurality of separate high voltage lines, each high voltage line connected separately to a first electrode of said first plurality of filament electrodes at the first end of a corresponding tube, said igniter means having a plurality of ground lines, each ground line connected to a first electrode of said second plurality of filament electrodes at the second end of a corresponding tube; and a plurality of auxiliary electrodes, each auxiliary electrode disposed in proximity to the external walls of a corresponding tube and extending the length of the tube between the first and second end, each said auxiliary electrode having an electric potential approximately equal to said first electrode of said second plurality of filament electrodes of said corresponding tube and means for providing an ionization voltage in common to said second filaments.