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. 09, 1997
Filed:
Nov. 17, 1995
Satoshi Ishii, Tokyo, JP;
Ko Ishizuka, Ohmiya, JP;
Hiroshi Kondo, Yokohama, JP;
Yasushi Kaneda, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An apparatus for optically detecting information relating to the relative displacement of an object on which a diffraction grating, arranged in two axial directions with a predetermined pitch. The apparatus includes a light-emitting device configured to emit a light beam, and a first optical element configured to divide the light beam from the light-emitting device into a plurality of light beams directed in each of the two axial directions to the diffraction grating on the object which produces a plurality of diffracted light beams for each of the two axial directions. The apparatus also includes a second optical element positioned and configured to receive and combine a plurality of diffracted light beams for each of the two axial directions from the diffraction grating on the object, and a plurality of detection units, each configured to receive and detect the combined plurality of diffracted light beams for one of the two axial directions, thereby detecting information relating to the relative displacement of the object in each of the two axial directions.