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:
Jan. 01, 1985
Filed:
Aug. 14, 1981
Applicant:
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01N / ;
U.S. Cl.
CPC ...
324 715 ; 324 / ;
Abstract
A device for measuring a flatness of a plate such as a silicon wafer, a GGG wafer, a printed circuit board, a ceramic substrate, or the like. The measuring device is provided with a disc which is disposed in parallel with the plate on one of the surfaces of the plate and is driven by a rotating drive source and a plurality of detectors for detecting a distance from the detector to the surface of the plate, the detectors being disposed on the surface closer to the disc. With this arrangement, distance data from the plurality of the detectors to the surface of the plate is obtained during the course of the rotation of the disc, and a flatness of the plate is measured.