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:
Oct. 01, 2002
Filed:
Nov. 23, 1999
Goro Fujita, Kanagawa, JP;
Kensuke Fujimoto, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
Light beams are irradiated from a head onto an optical disc including a recording layer and a reproduction (readout) layer to open, at the reproduction layer, detection window smaller than irradiation range of light beams to thereby read out recording information of the recording layer. A resolution detecting section detects resolution on tile basis of signal level of a reproduction signal reproduced from the optical disc . A signal level detecting circuit of the resolution detecting section detects signal level of a specific mark length signal corresponding to specific mark length data in the reproduction signal which has been reproduced, and a resolution calculating circuit calculates resolution on the basis of the detected signal level of specific mark length. A reproduction control circuit controls size of the detection window so that resolution from the resolution detecting section becomes close to reference value K from a reference value output circuit to thereby efficiently carry out aperture correction.