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. 02, 1997
Filed:
Feb. 15, 1996
Kou Ishizuka, Ohmiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An apparatus for detecting displacement information is disclosed. The apparatus is provided with a scale arranged on the side of an object of which relative displacement information is to be detected, a periodic signal generation diffraction grating formed at a predetermined pitch, and a predetermined data recording portion formed independently of the periodic signal generation and diffraction grating for detecting displacement information, a first detection system for irradiating a light beam onto the periodic signal generation diffraction grating to generate diffracted light, the first detection system forming a periodic signal corresponding to a displacement relative to the scale by detecting interference light of the diffracted light generated by the periodic signal generation diffraction grating, and a second detection system for optically detecting the predetermined data recording portion. The predetermined data recording portion also has a diffraction grating.