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:
Nov. 30, 2010
Filed:
Sep. 18, 2008
Applicant:
Noboru Osaka, Utsunomiya, JP;
Inventor:
Noboru Osaka, Utsunomiya, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B 3/00 (2006.01); G02B 9/00 (2006.01); G03B 27/54 (2006.01);
U.S. Cl.
CPC ...
Abstract
This invention is a projection optical system which includes a plurality of lens groups and projects an image of a first object onto a second object. A bottom lens group of the plurality of lens groups which is positioned nearest to the second object is made of an isotropic crystal material having a refractive index of 1.6 or more and has a positive focal length. A curvature radius R (mm) of a surface of the bottom lens group which is located on the first object side and a center thickness d (mm) of the bottom lens group satisfy 3.0>R/d>1.6 and d<60.