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:
Mar. 11, 1997
Filed:
Aug. 29, 1994
Koichi Sentoku, Atsugi, JP;
Takahiro Matsumoto, Atsugi, JP;
Noriyuki Nose, Atsugi, JP;
Minoru Yoshii, Tokyo, JP;
Kenji Saitoh, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A method and device for measuring the relative displacement between first and second diffraction gratings includes an interference optical system forming first and second interference rays of light from light diffracted from the first and second diffraction gratings and separating the first and second interference rays of light on the basis of the difference in their direction of polarization, a first detector for detecting the first interference ray of light to generate a first detection signal, a second detector for detecting the second interference ray of light to generate a second detection signal, and signal processing section for detecting the phase difference between the first and second detection signals and for determining the relative displacement between the first and second diffraction gratings on the basis of the phase difference.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile