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. 25, 2005
Filed:
Jun. 10, 2002
Takeshi Kamoi, Uji, JP;
Takahiro Abe, Morioka, JP;
Takeshi Kamoi, Uji, JP;
Takahiro Abe, Morioka, JP;
Matsushita Electric Works, Ltd., Osaka, JP;
Abstract
An electronic ballast for a discharge lamp is capable of dimming the lamp over a wide range, yet assuring to operate the lamp efficiently with a minimum lamp power variation in compensation for a possible lamp characteristic variation. The ballast provides an unique voltage-wattage output characteristic which varies with a varying dimming ratio for reducing the lamp power as the dimming ratio decreases. The output characteristic is designed to follow a true lamp characteristic that the lamp voltage will decrease as the lamp power is reduced to a certain level. With this result, it is possible to give a wide voltage range within which the lamp power being supplied to the lamp is kept substantially constant irrespective of the lamp characteristic variation, thereby assuring to reduce the lamp power exactly as intended by the dimming ratio even in the presence of the lamp characteristic variation.