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. 07, 1999
Filed:
Oct. 06, 1995
Yasuo Nakata, Takaichi-gun, JP;
Nobuo Ogata, Shiki-gun, JP;
Kunio Kojima, Nabari, JP;
Hideaki Sato, Yamatokoriyama, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
In an optical information recording-reproduction apparatus, a focus servo control circuit generates a focus error signal and a light beam is accurately converged on a surface of an optical disk according to a focus servo control signal based upon the focus error signal. In accordance with the present invention, the focus error signal is compensated by selecting a land section focus offset amount by a switch when land sections are tracked, and it is compensated by selecting a groove section focus offset amount when groove sections are tracked. As a result, since the land sections and the groove sections are controlled by different focus servo control signals, recording and reproducing operations are carried out at the most optimal focusing positions respectively obtainable, thereby making it possible to significantly improve the quality of a reproduced signal.