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:
Aug. 13, 2002
Filed:
Apr. 13, 2001
Applicant:
Inventors:
Hiroshi Nakatsuka, Osaka, JP;
Katsunori Moritoki, Osaka, JP;
Toshiyuki Asahi, Hyogo, JP;
Kojiro Okuyama, Nara, JP;
Osamu Kawasaki, Kyoto, JP;
Assignee:
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L 4/108 ;
U.S. Cl.
CPC ...
H01L 4/108 ;
Abstract
A method and unit for driving a small high-efficiency piezoelectric transformer allowing a cold-cathode tube to have stable luminance by detecting only an active current flowing in the cold-cathode tube based on a phase difference between an output current and voltage of the piezoelectric transformer, removing a reactive current caused by stray capacitance formed between the cold-cathode tube and a reflector, and accurately controlling driving of the piezoelectric transformer so that a constant active current is detected.