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:
Nov. 12, 1996
Filed:
Feb. 28, 1996
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 has a light source 1, a first diffraction grating G1 for diffracting and dividing the light from the light source and applying O-order diffracted light and +1st-order diffracted light to a second diffraction grating G2, a third diffraction grating G3 for combining +1st-order reflected diffracted light created by the O-order diffracted light being reflected and diffracted by the second diffraction grating and -lst-order reflected diffracted light created by the +lst-order diffracted light being diffracted by the second diffraction grating, to thereby form interference light, and a light receiving element 3 for photoelectrically converting the interference light, the third diffraction grating including four diffraction gratings given a phase difference of .pi./2 each, the light receiving element being provided with light receiving portions 3a1, 3a2, 3b1 and 3b2 corresponding to the four diffraction gratings of the third diffraction grating, and cruciform light intercepting means is provided between adjacent ones of the light receiving portions.