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:
May. 25, 2004
Filed:
Oct. 03, 2000
Applicant:
Inventor:
Masayuki Tanabe, Utsunomiya, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G21G 5/00 ; G01J 1/00 ; G01J 1/42 ;
U.S. Cl.
CPC ...
G21G 5/00 ; G01J 1/00 ; G01J 1/42 ;
Abstract
An optical instrument includes an optical element and a detector for detecting an impurity concentration in an ambience containing a space surrounding the optical element. By controlling the impurity concentration on the basis of an output of the detector, deposition of impurities on the optical element and deterioration of the optical characteristic of the optical element thereby can be prevented effectively.