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:
Apr. 12, 1994
Filed:
Jun. 24, 1992
Applicant:
Inventors:
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01D / ; H01J / ;
U.S. Cl.
CPC ...
2502 / ; 25023116 ;
Abstract
An encoder includes a light illuminating device, an optical scale and a photosensor, and detects information of relative displacement between the scale and the illuminating light. A birefringent element, such as a Savart plate or the like, is disposed in the optical path between the light illuminating device and the photosensor to generate a plurality of images of the scale having different phases. A plurality of output signals having a phase difference are obtained using the images of the scale.