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. 15, 2012
Filed:
Mar. 06, 2009
Takumi Tokimitsu, Utsunomiya, JP;
Takumi Tokimitsu, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
The present invention provides an optical element which is used for light having a wavelength not more than 250 nm, and receives a light beam at a maximum incident angle not less than 55°, wherein the optical element includes an optical thin film in an effective aperture thereof, and a film thickness distribution of the optical thin film in the effective aperture includes a distribution in which a thickness of the optical thin film in an outermost periphery of the effective aperture is 1.10 times (inclusive) to 1.25 times (inclusive) a thickness of the optical thin film at a midpoint between an optical axis and the outermost periphery of the effective aperture.