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. 24, 2007
Filed:
Apr. 23, 2002
Takahiro Miyake, Soraku-gun, JP;
Takahiro Miyake, Soraku-gun, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
According to the present invention, an optical pickup device forms one main spot, a first subspot, and a second subspot by irradiation of light on an optical disk having a groove part and a land part. The optical pickup device includes operation circuits which indicate a deviation between each of the optical spots and a track, and α detecting means for detecting such an α value that a difference in absolute value between SPPand αSPPfalls in a preset range, where an AC amplitude of a push-pull signal of the first subspot is SPP, and an AC amplitude of a push-pull signal of the second subspot is SPP, wherein SPP−αSPP(α is a constant) is a land/groove discriminating signal. With this, in the optical pickup device for recording and reproducing information on/from the optical disk having a land/groove part, it is possible to generate a land/groove discriminating signal and a tracking error signal without an offset, thereby performing excellent tracking control.