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:
Feb. 27, 1990
Filed:
May. 22, 1989
Applicant:
Inventors:
Koichiro Suzuki, Kanagawa, JP;
Toshihiro Sugikubo, Tokyo, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
360 746 ; 360 71 ;
Abstract
A device for detecting the light transmissivity of an object to be detected comprises a light emitting element and a light receiving element which are opposed to each other across the detected object. The device is arranged to cause the light emitting element to intermittently emit a light and to detect the light transmissivity of said detected object on the basis of a detection signal obtained from the light receiving element when the light is emitted by the light emitting element and another detection signal obtained from the light receiving element when no light is emitted by the light emitting element.