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:
Aug. 25, 1987
Filed:
Dec. 18, 1985
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A tracking control system for an optical disc information reproducing apparatus in which information stored in an optical disc as a series of recesses or pits arranged in concentric tracks or in a single spiral track is read out during rotation of the optical-disc by a scanning spot of a light beam, the system comprising a light source for generating the light beam used for scanning the track, means for applying the scanning spot of the light beam to a selected track location, a transducer for converting an optical signal detected by the scanning spot into an electric signal bearing a tracking error information, means for controlling the scanning spot applying means in response to the tracking error information signal, thereby causing the scanning spot to scan the selected track location accurately, means for transferring the tracking error information signal to the controlling means, a transfer characteristics of the transferring means being variable, means for limiting a slew rate of the tracking error information signal, means for subtracting an output of the slew rate limiting means from the tracking error information signal, and means for lowering the transfer characteristics of the controlling means in response to an output of the subtracting means, thereby causing the controlling means being irresponsive to the tracking error information signal.