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:
Jul. 09, 2013
Filed:
Mar. 18, 2009
Tooru Nagase, Gyoda, JP;
Yoshiaki Komatsu, Gyoda, JP;
Shinichi Suzuki, Gyoda, JP;
Makoto Ohkahara, Gyoda, JP;
Hirokazu Harasawa, Gyoda, JP;
Yoshiaki Kuroda, Gyoda, JP;
Tooru Nagase, Gyoda, JP;
Yoshiaki Komatsu, Gyoda, JP;
Shinichi Suzuki, Gyoda, JP;
Makoto Ohkahara, Gyoda, JP;
Hirokazu Harasawa, Gyoda, JP;
Yoshiaki Kuroda, Gyoda, JP;
Iwasaki Electric Co., Ltd., Chuo-ku, Tokyo, JP;
Abstract
The high pressure discharge lamp ballast drives a high pressure discharge lamp with a synthesized-waveform alternating current made of multiple frequency components, the high pressure discharge lamp having a pair of electrodes disposed to face each other. The ballast controls a ratio of the multiple frequency components per unit time; applies a synthesized-waveform current in accordance with the ratio to the high pressure discharge lamp; and detects a lamp parameter of the high pressure discharge lamp. The control circuit is configured to shift the ratio to a first ratio when the lamp parameter is in a first state, and shifts the ratio to a second ratio when the lamp parameter is in a second state. The control circuit changes the ratio stepwise when the ratio is shifted from the first ratio to the second ratio, or when the ratio is shifted from the second ratio to the first ratio.