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:
Sep. 15, 1987
Filed:
Sep. 05, 1985
Applicant:
Inventors:
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J / ; G01C / ;
U.S. Cl.
CPC ...
250578 ; 356-4 ;
Abstract
A system for photoelectrically detecting a light reflected from an object, such as a semiconductor wafer, irradiated by a light beam supplied from a light source, wherein the amount of irradiation is controlled so as to obtain an optimum photoelectrically-converted signal. According to another aspect of the invention, the amount of irradiation is controlled automatically on the basis of a reflectance of the object which has been detected preparatively. According to another preferred form of the invention, the amount of irradiation is controlled in a time-sharing fashion so as to obtain optimum photoelectrically-converted signals from different portions of the object.