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:
Mar. 08, 1988
Filed:
Mar. 18, 1986
Masahiro Takasago, Odawara, JP;
Osami Kushizaki, Hiratsuka, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An optical recording/reproducing apparatus for recording and reproducing information along tracks on an optical disc by irradiating the optical disc with a laser beam comprises a tracking error detecting circuit for detecting the digression of the laser beam from the center line of each track and a level detector for detecting that the output of the tracking error detecting circuit exceeds a predetermined level. An operation for recording information in the optical disc by the laser beam is stopped when the output of the level detector takes a predetermined state indicating that the output of the tracking error detecting circuit exceeds the predetermined level, for a first predetermined time, and a signal indicating the occurrence of off-track is generated when the duration time of the predetermined state in the output of the level detector exceeds a second predetermined time which is longer than the first predetermined time.