Capacitively driven RF light source having notched electrode for improved starting

摘要

A fluorescent light source includes a twin tube fluorescent lamp having first and second electrodes at or near the ends thereof for capacitive coupling of RF electrical energy to a low pressure discharge within the fluorescent lamp and a RF source having a first output lead electrically coupled to the first electrode and a second output lead electrically coupled to the second electrode. The capacitive coupling electrodes can be conductive layers on the outside surface of the twin tube fluorescent lamp. In an alternative configuration, the electrodes are cold cathode electrodes located within the twin tube fluorescent lamp. Filaments for emitting electrons are not required. When the RF voltage applied to the fluorescent lamp is not sufficient to initiate discharge, a starting device can be utilized. The fluorescent light source preferably includes a lamp base for supporting the fluorescent lamp. The RF source can be mounted within the lamp base.