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:
Nov. 07, 2017
Filed:
Feb. 25, 2015
Takahiro Nakayama, Kanagawa, JP;
Hiroshi Nakanuma, Kanagawa, JP;
Takahiro Nakayama, Kanagawa, JP;
Hiroshi Nakanuma, Kanagawa, JP;
RICOH COMPANY, LTD., Tokyo, JP;
Abstract
A retro-focus type imaging-optical system is disclosed. The imaging-optical system comprises, in order from an object side to an image side a first lens group, an aperture stop, and a second lens group. The first lens group includes, in order from the object side, a positive first F lens group and a negative first R lens group. The first F lens group includes a positive meniscus lens having a convex surface on the object side. The first R lens group includes a negative meniscus lens having a convex surface on the object side and a positive lens. The second lens group includes, in order from the object side, a positive second F lens group and a second R lens group, and the second F lens group includes a positive lens element having a convex meniscus shape on the image side.