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:
Apr. 18, 2006
Filed:
Dec. 05, 2003
Kunio Nakayama, Tokyo, JP;
Kunio Nakayama, Tokyo, JP;
Sony Disc & Digital Solutions Inc., Tokyo, JP;
Abstract
A laser beam is obtained from a semiconductor laser by a stable emission light amount. A first semiconductor laser is thermally coupled with a second semiconductor laser and driven by a feedback circuit constructed by a photodetector, an I-V converter, and a current generator so as to stabilize the emission light amount. A current I' having a correlation with a drive current Iof the 1st laser is outputted from a current mirror circuit. A modulation signal is supplied to a current pull-in type current driving circuit via a multiplier and a linearity compensating circuit and a current Iaccording to the modulation signal is extracted from a collector of a transistor. The 2nd laser is driven by a current I(I′−I) and a laser beam modulated by the modulation signal is generated. Since the signal modulation by the 2nd laser is performed without influencing on Iand the 2nd laser is driven by I′, the emission light amount is stabilized.