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. 14, 2003
Filed:
Mar. 20, 2001
Applicant:
Inventors:
Yoshihiro Shiode, Utsunomiya, JP;
Izumi Tsukamoto, Setagaya-ku, JP;
Hiroshi Morohoshi, Utsunomiya, JP;
Yoshio Kawanobe, Utsunomiya, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01B 1/100 ; G01N 2/186 ;
U.S. Cl.
CPC ...
G01B 1/100 ; G01N 2/186 ;
Abstract
A method of detecting focus information about an image projecting optical system includes performing mark projection through the optical system, and, based on illumination lights having different chief ray incidence directions, the mark projection is carried out so that mark images formed by the illumination lights, respectively, are superposed one upon another approximately upon an imaging plane, and detecting focus information about the optical system on the basis of information related to a deviation between the mark images superposed.