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:
Aug. 06, 2002
Filed:
May. 09, 2000
Yuu Okada, Moriguchi, JP;
Katsuya Watanabe, Nara, JP;
Tetsuya Shihara, Moriguchi, JP;
Akihiko Nishioka, Katano, JP;
Koujiro Okamoto, Suita, JP;
Matsushita Electric Industrial Co., Ltd., Kadoma, JP;
Abstract
An optical disk apparatus includes a converging section for converging a light beam toward an information carrier; a moving section for moving the light beam converged by the converging section in a direction perpendicular to a surface of the information carrier; a light detector for detecting the light beam reflected by the information carrier; a convergence state detecting section for generating a convergence state signal representing a convergence state of the light beam at a convergence point on the information carrier and outputting a reproduction signal from the information carrier, based on the output from the light detector; a focus controller for driving the moving section to make the convergence state constant based on the convergence state signal and a prescribed target position; a reproduction quality signal detector for detecting a reproduction quality signal representing a quality of the reproduction signal based on the reproduction signal; a reproduction quality signal measuring section for changing the target position and measuring a value of the reproduction quality signal corresponding to each of the changed target positions; a reproduction quality signal characteristic determining section for determining a characteristic of the reproduction quality signal based on the value of the reproduction quality signal corresponding to each of the changed target positions; and a target position searching section for searching for an optimum target position of the focus controller for optimizing the value of the reproduction quality signal based on a determination result of the reproduction quality signal characteristic determining section.