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. 17, 1991
Filed:
Dec. 29, 1989
Yuhei Kobayashi, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
A tracking control apparatus for use with an optical recording/reproducing apparatus includes a stationary optical section provided with a laser light source, a movable optical section provided with an objective lens by means of which three laser beams emanating from the laser light source are directed onto an optical disk, and a plurality of photodetectors having light receiving surfaces each divided into at least two segments adapted to receive the three reflected laser beams from the optical disk. A tracking control signal computing device taken the difference of detection outputs from the light receiving surfaces of said photodetectors to produce plural tracking error signals and divides the tracking error signals by the total light quantities received by the photodetectors for normalizing the tracking error signals to derive a tracking signal.