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. 26, 1997
Filed:
Oct. 02, 1996
Applicant:
Inventors:
Koh Ishizuka, Ohmiya, JP;
Yasushi Kaneda, Tokyo, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01B / ;
U.S. Cl.
CPC ...
25023114 ; 25023116 ; 2502 / ; 356356 ;
Abstract
A rotary encoder has a disk with fine gratings comprising diffraction gratings of small diameters and a high density. Two diffraction lights of predetermined orders which are obtained when a light beam is irradiated to the fine gratings, are interfered properly with each other, thereby enabling rotational information of a rotary object to be detected at a high resolution while realizing a small and thin size of the overall apparatus.