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:
Aug. 19, 1986
Filed:
Nov. 07, 1983
Koichi Wakamiya, Tokyo, JP;
Nippon Kogaku K.K., Tokyo, JP;
Abstract
A behind stop lens has, in succession from the object side, a first lens which is a positive meniscus lens having its convex surface facing the object side, a second lens which is a biconcave negative lens, a third lens which is a biconvex positive lens, and a fourth lens which is a negative meniscus lens having its convex surface facing the image side, the third lens and the fourth lens being cemented together to form a positive cemented lens. The behind stop lens satisfies the following conditions: ##EQU1## where f represents the total focal length of the entire system, .SIGMA.d represents the distance from the vertex of the object side lens surface of the first lens to the vertex of the image side lens surface of the fourth lens, f.sub.2 represents the focal length of the second lens, r represents the radius of curvature of each lens surface, n and .nu. represent the refractive index and the Abbe number, respectively, of each lens, and the subscript numbers mean the order from the object side.