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:
Dec. 05, 1995
Filed:
Sep. 13, 1994
Applicant:
Inventor:
Hitoshi Furuhata, Saitama, JP;
Assignee:
Pioneer Electronic Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4423 ; 369 4441 ; 369112 ;
Abstract
An optical pickup is adapted to be operated in accordance with a tracking error signal obtained by a push-pull method. The pickup has a photodetector including a pair of detector elements disposed side by side. An astigmatizer is disposed on an axis of a light beam reflected from an optical disc for producing an astigmatic beam. The photodetector is positioned outside a point where a spot of the astigmatic beam becomes a circular shape, and a boundary line between the two detector elements is disposed on a line along which the spot moves in a tracking operation.