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:
Sep. 18, 2012
Filed:
Jul. 08, 2011
Shuichi Minamiguchi, Tokyo, JP;
Hajime Nishimura, Tokyo, JP;
Hiroharu Sakai, Tokyo, JP;
Kazuhiko Ono, Yokohama, JP;
Shuichi Minamiguchi, Tokyo, JP;
Hajime Nishimura, Tokyo, JP;
Hiroharu Sakai, Tokyo, JP;
Kazuhiko Ono, Yokohama, JP;
Hitachi-LG Data Storage, Inc., Tokyo, JP;
Abstract
This invention provides accurate control of laser light power in a recording operation to achieve more stable recording operation. An optical disc drive in an embodiment of this invention monitors the power of laser light with a monitor diode and controls the laser light power based on the result of monitoring. The optical disc drive changes data transfer rate (recording frequency) depending on the disc radial position. The optical disc drive controls the gain of the monitor diode across the recording surface depending on the recording frequency. This control improves the accuracy in laser light power control to achieve stable recording operations by precise servo control.