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:
Dec. 18, 2012
Filed:
Jul. 07, 2011
Hajime Nishimura, Tokyo, JP;
Shuichi Minamiguchi, Tokyo, JP;
Hiroharu Sakai, Tokyo, JP;
Kazuhiko Ono, Yohohama, JP;
Hajime Nishimura, Tokyo, JP;
Shuichi Minamiguchi, Tokyo, JP;
Hiroharu Sakai, Tokyo, JP;
Kazuhiko Ono, Yohohama, JP;
Hitachi-LG Data Storage, Inc., Tokyo, JP;
Abstract
This invention provides an optical disc drive with more accurate and stable power control for a laser light source. An optical disc drive in an embodiment of this invention includes a monitor photodetector for receiving laser light emitted by a laser light source to monitor the laser light power. The monitor diode is a photodetector for generating an electric signal corresponding to the laser light power. A laser light controller controls drive current to the laser light source based on a result of measurement by the monitor diode. The optical disc drive measures output variations of the monitor diode and controls the gain of the monitor diode based on the result of the measurement. This gain control improves accuracy and stability in laser light control so that stability in recording/reading can be attained.