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:
Jul. 21, 1987
Filed:
May. 21, 1985
Masamichi Tateoka, Yokohama, JP;
Hideaki Yano, Kokubunji, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An optical information processing apparatus comprising record/reproduction devices for irradiating a focused light beam onto a track on a record medium to record or reproduce information tracking control devices for precisely directing the irradiated light beam to the track split devices for splitting at least a portion of a reflected or transmitted light beam of the irradiated light beam from the record medium into two light beams first screen devices for screening a center area of one of the split light beams across a width of the track second screen devices for screening a peripheral area of the other of the split light beams across the width of the track and detection devices for comparing light intensities of the two light beams transmitted without being screened by said first and second screen devices to detect a focusing state of the irradiated light beam to the record medium.