摘要 |
A first waveform (a rectangular waveform, for example) is applied as the waveform of the alternating current supplied to a high-pressure discharge lamp for a predetermined time from the beginning of lighting of the lamp and a second waveform (a staircase waveform, for example) is applied as the waveform of the alternating current after the elapse of a predetermined time (100 [s], for example). The alternating current with the first waveform has a lower absolute instantaneous value in a final section of each half-cycle period thereof than in the other sections and the alternating current with the second waveform has a higher absolute instantaneous value in a final section of each half-cycle period thereof than in the other sections. |