The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 10, 2000
Filed:
Sep. 24, 1998
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A discharge lamp operating apparatus has a glass envelope for defining a discharge space and a pair of electrodes which are hermetically sealed within the glass envelope and are opposed to each other. The apparatus includes (1) generation element for generating a waveform signal having an acoustic resonant frequency for exciting a mode, in which a discharge arc between the pair of electrodes is straightened and (2) modulation element for modulating the waveform signal so that a polarity of the center line of the waveform signal is alternately changed at a lower frequency than the acoustic resonant frequency. If the value of the amplitude of the waveform signal from peak to peak is .alpha., and the effective value of the modulated waveform signal is .beta., then the depth of modulation .alpha./.beta. at the beginning of operation is equal to or less than the depth of modulation .alpha./.beta. at an operation under rated condition.