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:
Aug. 11, 1987
Filed:
Mar. 01, 1985
Kenichi Kodama, Kawasaki, JP;
Akikazu Tanimoto, Yokohama, JP;
Hisao Izawa, Kawasaki, JP;
Yoichi Hamashima, Kawasaki, JP;
Junji Hazama, Kawasaki, JP;
Nippon Kogaku K.K., Tokyo, JP;
Abstract
An apparatus for optically measuring the very small gap between a reference plane and a substrate parallel to the reference plane. A beam of energy converging on the reference plane is reflected by the substrate and a spot of reflected beam is formed on a detecting plane at a different position. An array of detecting elements for detecting the size of the spot on the detecting plane is adjusted in position in such a manner that the center of the spot coincides with the center of any one of the detecting elements, thereby preventing any error of the in-focus detecting position due to the deviation between the center of the spot and the center of the detecting element.