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:
Jul. 24, 2012
Filed:
Aug. 27, 2009
Kazue Uchida, Utsunomiya, JP;
Takeharu Okuno, Utsunomiya, JP;
Daisuke Sano, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
The optical element includes a base member configured to have an optical surface, a concave-convex structure configured to have an average pitch smaller than a shortest wavelength of a use wavelength range, and an intermediate layer formed between the optical surface and the concave-convex structure, made of a material different from that of the concave-convex structure, and having a refractive index between those of the base member and the material of the concave-convex structure. The optical surface is formed into a shape having a rotational symmetry axis. A thickness of the intermediate layer or each of thicknesses of the intermediate layer and the concave-convex structure varies so as to increase as a distance from the rotational symmetry axis increases. The optical element has good anti-reflection performance not only at a central part of the optical surface having a small curvature radius but also at a peripheral part thereof.