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:
Nov. 02, 2010
Filed:
Aug. 25, 2008
Tsutomu Ishimoto, Tokyo, JP;
Tsutomu Ishimoto, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical pickup device is provided. The optical pickup device includes a light source, a focusing optical system configured to irradiate an optical recording medium with near-field light, a light-detecting unit configured to detect a total-reflection return-light quantity from the optical recording medium, a control unit configured to generate a control signal in response to a detection signal supplied from the light-detecting unit, and a drive unit configured to drive the focusing optical system to a predetermined position above the optical recording medium. The control unit feeds forward a push-pull signal in a traveling direction of the drive unit relative to the optical recording medium to a gap-error signal supplied from the light-detecting unit to generate a gap-servo signal. The control unit includes a repetitive controller storing a predetermined number of the push-pull signals.