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:
Oct. 21, 1986
Filed:
Jan. 16, 1984
Applicant:
Inventors:
Dale C Flanders, Lexington, MA (US);
Theodore M Lyszczarz, Concord, MA (US);
Assignee:
Massachusetts Institute of Technology, Cambridge, MA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01B / ;
U.S. Cl.
CPC ...
356357 ; 356358 ;
Abstract
A lens or fiberoptic cable focuses energy from a collimated helium neon laser beam upon a point on a mask. Some of the focused energy is reflected from the mask upon a photodetector array in an image plane, and some of this energy is reflected from a substrate closely adjacent to the mask after passing through the mask upon the photodetector array to produce an interference pattern that is sensed and characterized by a spatial frequency representative of the distance between the mask and substrate.