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. 05, 1989
Filed:
Feb. 25, 1988
Applicant:
Inventor:
Vincent J Coates, Palo Alto, CA (US);
Assignee:
Nanometrics Incorporated, Sunnyvale, CA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01B / ;
U.S. Cl.
CPC ...
356384 ; 356387 ; 2504591 ;
Abstract
A feedback method, or automatic gain control circuit, for an image photosensor at the focal plane of an optical system for very narrow linewidth measurements of images having varying intensities such as fluorescing photoresist coated lines. The feedback method includes the steps of measuring the instantaneous intensities of the entire optical beam of radiation with a photodetector and applying the output therefrom to the photosensor to thus normalize its output signal.