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:
Dec. 30, 1986
Filed:
Oct. 07, 1983
Toshio Akatsu, Ibaraki, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A clearance formed between two members is measured by optical means projecting a light beam on the respective members and utilizing lights reflected therefrom. The reflected lights from the two members are passed through means capable of regulating an optical length and polarization means, whereupon they are caused to interfere. The irradiance of the interference light is converted into an electric signal. The electric signal is applied to a control circuit, and is fed back to the means capable of regulating an optical length so that the optical-path difference of the reflected lights may be held constant. The change of the clearance between the two members is found by measuring the factor of the feedback.