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. 02, 2007
Filed:
Jul. 10, 2006
Fumio Haruna, Yokohama, JP;
Masaru Shimizu, Kamakaura, JP;
Kouji Kitou, Hiratsuka, JP;
Tetsunosuke Nakamura, Yokohama, JP;
Fumio Haruna, Yokohama, JP;
Masaru Shimizu, Kamakaura, JP;
Kouji Kitou, Hiratsuka, JP;
Tetsunosuke Nakamura, Yokohama, JP;
Hitachi Media Electronics Co., Ltd., Iwate, JP;
Abstract
A computing circuit computes a target value of a current to be supplied to a discharge lamp and generates a pulse control signal for superpose a pulse current. Furthermore, the computing circuit controls a current control circuit so that a pulse current is superposed on a lamp current at a predetermined cycle and power supplied to the discharge lamp is kept constant. For that purpose, the computing circuit lowers a DC current level of the lamp current when a pulse current is superposed on the lamp current, and exercises control so that an integrated amount of power at a predetermined cycle is equalized to a predetermined integrated amount of power.