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:
Sep. 02, 2008
Filed:
Oct. 08, 2003
Kenzo Ishibashi, Moriguchi, JP;
Eiji Ueda, Yawata, JP;
Masahiro Birukawa, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A tracking control apparatus for stable tracking lead-in of an optical disc which has wobble grooves as tracks, including: a signal detection unit that detects tracking error and wobble signals from an optical spot; a speed detection unit that calculates a relative moving speed between the optical spot and the tracks; a polarity judgment unit that judges that the optical spot is on a land if a wobble signal amplitude value is equal to or lower than a predetermined value in the vicinity of a zero-cross point; a moving direction judgment unit that, when the relative moving speed is within a predetermined range and the optical spot is on a land, judges a moving direction of the optical spot from a rise/decay direction of the tracking error signal; and a control unit that performs a tracking lead-in by reducing the moving speed, based on the moving speed and moving direction.