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:
Jul. 20, 2010
Filed:
Aug. 27, 2007
Akihiro Ashida, Urayasu, JP;
Kikuo Shimizu, Kawasaki, JP;
Motoyuki Suzuki, Yokohama, JP;
Hitachi-LG Data Storage Inc., Tokyo, JP;
Abstract
This invention provides an optical disc device that can prevent the occurrence of an error in a starting position of a write operation due to off-tracking, and to avoid an unnecessary stop of the write operation during writing. A tracking error signal generator generates a tracking error signal from a signal which has been detected by an optical pickup, and a system controller detects off-tracking by comparing the tracking error signal with a threshold level, and turns control operation of a tracking servo controller off if the threshold level is exceeded. The off-tracking detection threshold level applied during a time period from completion of seek operation to a start of movement of the optical pickup to the starting position of the write operation is set to be lower than a threshold level applied during a time period of data recording.