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:
Mar. 26, 2013
Filed:
Feb. 18, 2011
Hiroharu Sakai, Tokyo, JP;
Koji Kaniwa, Yokohama, JP;
Hajime Nishimura, Tokyo, JP;
Hitachi-LG Data Storage, Inc., Tokyo, JP;
Abstract
In an optical disc device, a way of canceling a lens shift due to an electric offset of an output of a tracking actuator driving circuit is desired. A tracking servo control circuit contains a first operation mode for setting an output current of the tracking actuator driving circuit to generally zero and a second operation mode for supplying a predetermined potential to the input. An average potential of a push-pull signal detected in the first operation mode is acquired. An object lens is moved by a predetermined amount in both radial directions by changing a potential supplied in the second mode to acquire correlative relationship between average potential of a push-pull signal relative to a lens movement amount and the supplied potential. An offset amount is acquired from the potential and the correlative relationship to cancel the offset.