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. 12, 1993
Filed:
Nov. 16, 1990
Hitachi, Ltd., Tokyo, JP;
Abstract
A tracking control apparatus is provided for controlling a displacement error between a pickup system and a track when reproducing information recording on an information-recording and reproducing medium having tracks on which information is recorded or reproduced. The tracking control apparatus includes on-track detecting means for detecting a light beam is located on the track, traveling-direction detecting means for detecting the direction of the pickup system traveling toward the track from the displacement error and the output signal supplied by the on-track detecting means and outputting a traveling-direction signal representing the traveling direction, track-slippage detecting means for detecting a track-slippage signal representing the direction of the light beam being slipped out of a target track from the traveling-direction signal supplied by the traveling-direction detecting means, and tracking control means for supplying as a control signal the displacement error when the light beam is located on the target track or as a control signal the track-slippage signal supplied by the track-slippage detecting means when the light beam is not spotted on the target track and driving the pickup system in a manner to allowing the light beam to follow the tracks.