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:
Sep. 02, 2014
Filed:
Jun. 24, 2011
Hisanori Suzuki, Sukagawa, JP;
Shingo Watanabe, Sukagawa, JP;
Ichiro Kurihara, Sukagawa, JP;
Kazuo Matsuoka, Saitama, JP;
Hisanori Suzuki, Sukagawa, JP;
Shingo Watanabe, Sukagawa, JP;
Ichiro Kurihara, Sukagawa, JP;
Kazuo Matsuoka, Saitama, JP;
Kantatsu Co., Ltd., Tochigi, JP;
Abstract
A concave surface is formed on an object side of a plastic lens of a one-piece construction, and a convex surface is formed on an image-point side thereof. The concave and convex surfaces are aspherical. A diffractive optical surface that exerts a chromatic dispersion ability is formed on the convex surface, and conditional expressions (1) 0.45<L/R<0.95 and (2) −0.065<L'(1−n)/R′<0.035n are met, where assuming that a position at which a chief ray and an optical axis intersect is regarded as an apparent stop, L denotes a distance to the apparent stop seen from the apex of the convex surface, L′ denotes a distance to the apparent stop seen from the apex of the concave surface, R denotes a curvature radius of the convex surface, R′ denotes a curvature radius of the concave surface, and n denotes a refractive index of a lens material.