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:
Jul. 28, 1992
Filed:
Aug. 14, 1990
Applicant:
Inventors:
Ilan A Blech, Sunnyvale, CA (US);
Dov E Hirsch, Cupertino, CA (US);
Assignee:
Flexus, Inc., Sunnyvale, CA (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01N / ; G01B / ;
U.S. Cl.
CPC ...
250560 ; 356371 ; 250226 ;
Abstract
In accordance with the present invention, an apparatus and a method for measuring the radius of curvature of a surface using laser beams of multiple wavelengths are provided. The present invention avoids poor measurement due to destructive interference of the beams reflected at a thin film's upper and lower surfaces. The present invention is applicable to laser reflection stress measurement apparatuses of both scanning and beam-splitting types.