ELECTRODELESS DISCHARGE LAMP

摘要

PURPOSE:To provide an electrodeless discharge lamp which does not need large electric power supply for its starting auxiliary electrodes and has good starting properties. CONSTITUTION:A wire of an induction coil 2 is coiled on the outer circumference of a bulb 1 made of a transparent material and high frequency current is carried to the induction coil 2 from a high frequency electric power source 4. A discharge gas is sealed in the bulb 1 and a high frequency electromagnetic field in the surroundings of the induction coil 2 is applied to the discharge gas to excite the discharge gas and emit light. Two starting auxiliary electrodes 3a, 3b which are put along the coiled direction of the induction coil 2 are formed in the circumferential wall of the bulb 1. The starting auxiliary electrode 3a has a length about three fourth of the circumference and the starting auxiliary electrode 3b has a length about one fourth of the circumference. The starting auxiliary electrode 3b is earthed. In the case high frequency current is carried to an induction coil 2 after high frequency voltage is applied to the starting electrodes 3a, 3b to generate predischarge, the lamp lights easily.