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:
Apr. 17, 2007
Filed:
Apr. 22, 2005
Kenichiro Mori, Utsunomiya, JP;
Kenichiro Mori, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An illumination optical system for illuminating a target surface using light from a light source, said illumination optical system includes a polarizing element that is arranged in an optical path from the light source to the target surface, and adjusts a polarization ratio of the light, and an optical element that is arranged in an optical path from the polarizing element to the target surface, wherein the total birefringence of the optical element is m+2σ<1.0 nm/cm, where an average of birefringence amount of a glass material of the optical element is m, and standard variation birefringence amount of a glass material of the optical element is σ.