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:
Sep. 08, 1992
Filed:
Jan. 23, 1990
Satoshi Shikichi, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
In an optical information recording and/or reproducing apparatus, tracking and/or focusing error signals from relected light which are caused when a light spot is irradiated onto an optical recording medium are detected. Tracking and/or focusing servo circuits in the apparatus cause an objective lens to follow the medium on the basis of the result of the detection of the tracking and/or focusing error signals. When it is detected that the tracking and/or focusing error signals have reached a target value which is previously set to exceed a zero-cross point or a zero-cross level at the signal level, the tracking and/or focusing servo circuit is closed and the tracking and/or focusing servo is pulled in.