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:
Jan. 04, 2011
Filed:
Oct. 20, 2005
Katsuya Watanabe, Nara, JP;
Akira Yoshikawa, Nara, JP;
Shin-ichi Yamada, Osaka, JP;
Junichi Minamino, Nara, JP;
Katsuya Watanabe, Nara, JP;
Akira Yoshikawa, Nara, JP;
Shin-ichi Yamada, Osaka, JP;
Junichi Minamino, Nara, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An optical disk apparatus according to the present invention is capable of reading data from an optical diskwhich has a plurality of information recording layers, including a first information recording layer whose distance from a disk surface is relatively small and a second information recording layer whose distance from the disk surface is relatively large. This optical disk apparatus includes: a focus control sectionfor causing a converging point of the light beam to be positioned on an arbitrary information recording layer of the optical disk; a tracking control sectionfor causing the converging point of the light beam to be positioned on a predetermined track of the information recording layer; and a gain switching sectioncapable of changing gain characteristics of at least one of the focus control sectionand the tracking control section. The gain switching sectionprescribes a gain crossover frequency when reading data from the first information recording layer to be a value which is lower than a gain crossover frequency when reading data from the second information recording layer.