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. 21, 1999
Filed:
Feb. 21, 1996
Applicant:
Inventors:
Kou Ishizuka, Omiya, JP;
Takayuki Kadoshima, Utsunomiya, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01B / ;
U.S. Cl.
CPC ...
356356 ; 356354 ; 2502 / ;
Abstract
An apparatus for obtaining displacement information relative to a member includes a light source for illuminating a phase type diffraction grating on the member, an amplitude grating arranged at the position where interference fringes are generated immediately after emerging of diffracted light from the phase type diffraction grating illuminated by the light source, and a light-receiving element for receiving light emerging from the amplitude grating. The light-receiving element generates a periodic signal as displacement information upon relative movement of the member.