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:
Feb. 12, 2013
Filed:
Aug. 25, 2009
Daisuke Sano, Utsunomiya, JP;
Daisuke Sano, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
The optical element includes a base member, and a first layer which is formed on the base member and whose refractive index for a central use wavelength λ changes in a thickness direction of the first layer by 0.05 or more. The first layer has an anti-reflection function and satisfies n=n−n), 0.5≦[n{t(n)/2}−n]/[n−n{t(n)/2}]≦0.8, λ/4≦t(n)≦2λ and 1.0≦nrepresents a refractive index of a most light entrance side part of the first layer for the central use wavelength, nrepresents a refractive index of a most base member side part of the first layer for the central use wavelength, t(n) represents an optical film thickness of the first layer at which the refractive index thereof for the central use wavelength is n, and n{t(n)/2} represents a refractive index of the first layer for the central use wavelength at a position where the optical film thickness ism t(n)/2.