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. 23, 1986
Filed:
Jul. 23, 1984
Katsuyuki Tanaka, Ibaraki, JP;
Seiichiroo Terashima, Ibaraki, JP;
Yoshinori Takeuchi, Ibaraki, JP;
Toshiko Odaka, Ibaraki, JP;
Yokuo Saito, Kanagawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
One of two articles arranged to form a fine clearance therebetween is made of a transparent material through which a light flux is impinged to the other article to form a reflection light which includes an interference fringe pattern information representing the fine clearance between the two articles. The reflection light is focused on a photo-electric conversion plane and converted to an electrical signal. The photo-electrically converted interference fringe pattern information is then converted to digital information, which is stored in a frame memory. A computer reads out the digital information from the frame memory and determines peak positions of light and/or dark areas of the interference fringe to measure the fine clearance between the two articles.