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:
Nov. 10, 2009
Filed:
Feb. 21, 2007
Kazuhiko Miyazaki, Kyoto, JP;
Kiyoshi Masaki, Hyogo, JP;
Hideki Shirane, Ehime, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An optical disc apparatus has: an optical headfor emitting a light beam onto a predetermined track of an optical discbefore tracking control in order to detect reflected light with a photodetector; an arithmetic circuitfor generating measurement signals each indicative of a time-varying change of light received on a respective one of a plurality of light receiving areas of the photodetector; an A/D converter circuitfor A/D converting each measurement signal; a microcomputerfor determining a correction value based on a difference, in terms of high- and low-frequency components, between measurement signals having been A/D converted; and an adder circuitfor adding the correction value to a driving value output from a tracking control circuit, so that the driving value is corrected.