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:
Feb. 07, 2012
Filed:
Mar. 30, 2005
Isao Ichimura, Tokyo, JP;
Isao Ichimura, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical disc recording and playback apparatus includes an optical pickup performing an operation for recording and playing back signal information into and from an optical disc; an optical element allowing a light beam irradiated onto an optical disc by the optical pickup to be split into a main beam and sub-beams on both sides of the main beam and supplying the beams to the optical disc; an optical detector detecting return light from the optical disc; and a computation circuit detecting a track control error signal by a phase difference method and a differential push-pull method by using the detection signal from the optical detector and also detecting a wobble signal.