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. 19, 1999
Filed:
Sep. 03, 1997
Applicant:
Inventors:
Shigeru Ishimoto, Yokohama, JP;
Toyohiko Matsuda, Yokohama, JP;
Assignee:
Sony Precision Technology Inc., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01B / ;
U.S. Cl.
CPC ...
702155 ; 702 94 ; 702150 ; 702158 ; 364182 ; 36447435 ;
Abstract
In apparatus and method for measuring a displacement of an object to be measured, a magnitude of the displacement is derived on the basis of a difference in periods of a phase modulated signal and a reference signal, a ratio between the periods of a basic clock and of an interpolation clock which is varied according to the magnitude of the displacement, a clock signal whose period is a multiplication of a period of the basic clock by the ratio as a multiplier, a pulse train signal is created whose number of pulses are given by the magnitude of the displacement and supplied to an A/B phase converter.