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:
Oct. 21, 1997
Filed:
Sep. 08, 1995
Yasushi Kaneda, Tokyo, JP;
Koh Ishizuka, Ohmiya, JP;
Hiroshi Kondo, Yokohama, JP;
Satoshi Ishii, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A displacement detection apparatus includes a light source (1), a first diffraction grating (G1) which is arranged on the same substrate as a second diffraction grating (G2) so as to diffract and split light emitted from the light source and to irradiate .+-.1st-order diffracted light beams onto the second diffraction grating (G2), a third diffraction grating (G3) for synthesizing a +1st-order reflectively diffracted light beam generated by reflectively diffracting the +1st-order diffracted light beam by the second diffraction grating, and a -1st-order reflectively diffracted light beam generated by reflectively diffracting the +1st-order diffracted light beam by the second diffraction grating to form interference light, and a light-receiving element (3) for converting the interference light into a signal representing a displacement of the substrate.