Patent ID: 6130508
Filing Date: 2000-10-10
Classification: H05B,Y02B

Abstract:
A discharge lamp operating apparatus for operating a discharge lamp having a glass envelope for defining a discharge space and a pair of electrodes which are hermetically sealed within said glass envelope and are opposed to each other, comprising:generation means for generating a waveform signal having an acoustic resonant frequency for exciting a mode, in which a discharge arc between said pair of electrodes is straightened; andmodulation means for modulating said waveform signal so that a polarity of a center line of said waveform signal is alternately changed at a lower frequency than said acoustic resonant frequency, whereinif a value of an amplitude of said waveform signal from peak to peak is .alpha., and an effective value of said modulated waveform signal is .beta., then a depth of modulation .alpha./.beta. at a beginning of operation becomes equal to or less than a depth of modulation .alpha./.beta. at an operation under rated condition.