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:
Feb. 17, 1998
Filed:
Sep. 20, 1995
Applicant:
Inventor:
Naoki Kawamata, Utsunomiya, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R / ; G01B / ;
U.S. Cl.
CPC ...
364561 ; 364486 ; 36457101 ; 356356 ; 356358 ;
Abstract
This invention relates to a method of and an apparatus for detecting the amount of displacement of an object by the use of two periodic signals having a predetermined phase difference therebetween which are outputted in conformity with the displacement of the object. The apparatus has means for detecting the two periodic signals, means for calculating the ratio between the two periodic signals, and means for obtaining the amount of displacement of the object from the value of the ratio by reference to prestored data.