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. 10, 1993
Filed:
Jun. 11, 1990
Yasuo Ogino, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An optical information recording-reproducing apparatus includes a scanning device for scanning a recording medium by a light beam and effecting the recording and/or reproduction of information, controller for effecting the auto focusing control and/or the auto tracking control of the light beam, an error signal detecting circuit for detecting an error signal for driving the controller, a plurality of sample hold circuits for periodically sampling the error signal at different times, an abnormality detecting circuit for detecting an abnormality of in the behavior of the error signal, a circuit for discontinuing the sampling when the sampling starting time of the sample hold circuits comes within a period during which the abnormality is being detected by the abnormality detecting circuit, a selecting circuit for selecting one of the plurality of sample hold circuits and supplying the output of the selected circuit to the controller, and an instructing circuit for instructing the selecting circuit to select the other sample hold circuit when an abnormality is detected by the abnormality detecting circuit during the sampling period of the selected sample hold circuit.