| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lighting device for a high-pressure discharge lamp enabling extension of the service life of the high-pressure discharge lamp. <P>SOLUTION: This lighting device for the high-pressure discharge lamp has an alternating current supplying means for supplying, to the high-pressure discharge lamp having one pair of electrodes, low-frequency rectangular current of 50 Hz to 1 kHz, and alternating current that is formed of one cycle of high-frequency rectangular current higher than 1 kHz inserted during the polarity reversal of the low-frequency rectangular current and where at least the peak current value of a half cycle of second half, of the one cycle of high-frequency rectangular current, is higher than the current value of the low-frequency rectangular wave. The first frequency is set lower than the second frequency, the waveform of low frequency rectangular current is formed of repetition of positive current half-wave element of a frequency selected from the first or second frequency and negative current half-wave element of a frequency selected from the first or second frequency, and, in a predetermined period, is a waveform where the effective value of the positive current half-wave element of the first and second frequencies is substantially equal to the effective value of the negative current half-wave element of the first and second frequencies. <P>COPYRIGHT: (C)2009,JPO&INPIT |
