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. 21, 1990
Filed:
Apr. 21, 1988
Tadashi Saitoh, Fujisawa, JP;
Takashi Takeucchi, Fujisawa, JP;
Masayuki Hirabayashi, Yokohama, JP;
Junichi Iida, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In an apparatus for tracking an optical disk, readiness in acquiring a steady tracking condition is significant. That is, if the light beam is subjected to feed back while it is positioned in a positive feed back region, e.g., in the middle of adjoining tracks, the track servo system causes an oscillation. Therefore, according to the present invention, the magnitudes of signals from two pits disposed offset from the track and a pit on the track are compared whereby position of the light beam is detected so that the tracking error signal may be cut off when the light beam is positioned in the middle of adjoining tracks.