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:
Jan. 19, 1993
Filed:
Nov. 01, 1989
Sony Corporation, Tokyo, JP;
Abstract
An optical pickup device for a recording and/or reproducing apparatus in which a light beam from a semiconductor laser element is converged by an object lens and irradiated on recording tracks of an optical disk and the light reflected by the disk is sensed to read and/or record data signals. The device includes photosensors each having an insensitive central zone and adapted to receive the reflected light to generate tracking error signals. The semiconductor laser element is so arranged that the light beam is projected on the optical disk so that the meridional plane of the light beam orthogonal to the junction plane of semiconductor layers of the semiconductor laser element is at such an angle with respect to a tangential line drawn to one of the recording tracks of the optical disk that non-symmetricities on both sides of said tangential line as a function of the de-focusing direction of the beam spot may be compensated.