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.

Date of Patent:
Sep. 10, 2013

Filed:

Apr. 25, 2011
Applicants:

Tatsuya Orihara, Hachioji, JP;

Tsutomu Uzawa, Hidaka, JP;

Inventors:

Tatsuya Orihara, Hachioji, JP;

Tsutomu Uzawa, Hidaka, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B 13/18 (2006.01);
U.S. Cl.
CPC ...
Abstract

An objective optical system includes, in order from an object, a negative-powered first-lens, an aperture stop, a positive-powered second-lens, and a third-lens, wherein: a surface of the first-lens which is closest to an image is a concave surface; a surface of the second-lens which is closest to the image is an aspheric surface; a surface of the third-lens which is closest to the object is a convex surface; the objective optical system has a three-group, three-lens configuration in which each of the first- to third-lenses is made up of a single lens and all surfaces of the three lenses have power; a distance d_Lbetween the second-lens and the third-lens is smaller than a distance d_Lbetween the first-lens and the second-lens, satisfying a conditional d_L/d_L<0.25; and a focal length f_Lof the second-lens, and a focal length f_Lof the third-lens satisfy the conditional 1.7<f_L/f_L


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