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:
Dec. 25, 1984
Filed:
Oct. 22, 1982
Hiroichi Shinohara, Kanagawa, JP;
Ricoh Company, Ltd., , JP;
Abstract
A stop is disposed forwardly of the lens system which comprises three individual lenses. A first lens located nearest the stop represents a positive meniscus lens, followed by a second and a third individual lens, both of which represent negative meniscus lenses. Each of the first to the third lens has its concave surface directed toward the stop. A small air gap exists between the second and the first lens. Representing the focal length of the first lens by f.sub.1, the composite focal length of the first and the second lens by f.sub.1,2, the composite focal length of the first to the third lens by f, the radius of curvature of a second refractive surface in the lens system by r.sub.3, the radius of curvature of a third refractive surface by r.sub.4, the refractive index of the first lens by n.sub.1, and the Abbe number of the first and the second lens by .nu..sub.1, .nu..sub.2, respectively, these parameters satisfy the following inequalities.