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:
Oct. 02, 2012

Filed:

Jan. 10, 2011
Applicant:

Ryoko Tomioka, Saitama, JP;

Inventor:

Ryoko Tomioka, Saitama, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B 15/14 (2006.01);
U.S. Cl.
CPC ...
Abstract

A zoom lens includes a negative first lens-group, a positive second lens-group, and a positive third lens-group, sequentially arranged from the object side. The focal length magnification of the zoom lens is changeable by changing a distance between the lens-groups. The first lens-group is composed of a negative first lens, the image side of which is concave, and a positive second lens that is an aspheric plastic lens. The second lens-group is composed of a cemented lens and a meniscus-form fifth lens having a convex surface facing the object side. The cemented lens is composed of a double-convex-form positive third lens and a double-concave-form negative fourth lens. The third lens-group is composed of a positive sixth lens, which is a single lens. Formula (1) about focal length fG2 of the second lens-group and focal length fw of the entire system at wide end is satisfied:1.10<2/<1.33  (1).


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