HIGH PRESSURE DISCHARGE LAMP OPERATION DEVICE AND OPERATION METHOD

摘要

Even if a temperature difference is generated between electrodes when AC current is supplied to a high-pressure discharge lamp, it is possible to eliminate the temperature difference and suppress arc movement during a stable ON state and flicker caused by the arc movement. Lamp current consists of a reference cycle current supplied at a predetermined reference cycle and a short-cycle current having a shorter cycle. At each half-cycle of the reference cycle current, a current waveform is formed by one cycle of the short-cycle current which reverses the polarity from the same polarity as the next half cycle to the reverse polarity. The duty ratio before and after the polarity inversion of the short-cycle current can be set to an arbitrary value.