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:
Mar. 21, 2006
Filed:
May. 20, 2002
Takeshi Kamoi, Uji, JP;
Minoru Maehara, Matsubara, JP;
Masanori Mishima, Souraku-gun, JP;
Takahiro Abe, Morioka, JP;
Takeshi Kamoi, Uji, JP;
Minoru Maehara, Matsubara, JP;
Masanori Mishima, Souraku-gun, 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 minimizing a color temperature deviation. The ballast includes a power converter which converts an input DC voltage into a lamp power for driving the lamp, and a dimmer providing a dimmer command of a varying dimming ratio in order to reduce the lamp power to a greater extent as the dimming ratio decreases. A controller controls the power converter to supply a high frequency AC current to the lamp in response to the dimming ratio decreasing to a predetermined level, and to reduce an RMS value of the high frequency AC current as the dimming ratio decreases past the predetermined level.