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:
May. 28, 1985
Filed:
Mar. 03, 1983
Abstract
A tracking servo system for an optical-disc information reproducing apparatus includes (a) a light source for generating a light beam to scan a target track on an optical-disc wherein the information is stored as a series of pits arranged in the form of the track; (b) four photodetectors, arranged in two pairs with each pair intersecting the other and being disposed in a direction oblique to an image of the track for converting an image of the pit into respective electric signals; (c) a circuit for comparing the phases of the electric signals and for producing a tracking error signal ranging in accordance with the phase difference between the electric signals; and (d) a motor and lens for deflecting the light beam along a path perpendicular to the target track in response to the tracking error signal, whereby the light beam accurately scans the target track.