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. 05, 2017
Filed:
Apr. 01, 2015
Nikon Corporation, Chiyoda-ku, Tokyo, JP;
Taku Matsuo, Kawasaki, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Provided is an eyepiece optical system including, in order from an observation object (Ob): a first lens (L) having positive refractive power; a second lens (L) which has negative refractive power and of which an observation object (Ob) side lens surface is concave; and a third lens (L) which has positive refractive power and of which an eye point (EP) side lens surface is convex. The third lens (L) is fixed on the optical axis with respect to the observation object (Ob) when adjusting the diopter, and the following conditional expressions are satisfied:0.65<31/1.30  (1)−0.80<(32+31)/(32−31)<−0.10  (2)where fe denotes a focal length of the eyepiece optical system, Rdenotes a radius of curvature of the observation object (Ob) side lens surface of the third lens (L), and Rdenotes a radius of curvature of the eye point (EP) side lens surface of the third lens (L).