US 10,520,702 B2Granted

Imaging lens

AssigneeKantatsu Co., Ltd.

InventorsYoji Kubota, Kenichi Kubota, Hitoshi Hirano, Tomohiro Yonezawa

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Abstract

An imaging lens includes a first lens group; a second lens group; and a third lens group. The first lens group includes a stop, a first lens having positive refractive power, a second lens, and a third lens. The second lens group includes a fourth lens and a fifth lens. The third lens group includes a sixth lens and a seventh lens. The first to seventh lenses are arranged on an optical axis with a space in between respectively. The fifth lens is formed in a meniscus shape near an optical axis thereof. The seventh lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius. The surface of the seventh lens on the image plane side is formed in an aspheric shape having at least one inflexion point. The third lens has a specific Abbe's number.

Claims18

Dependent claims

An imaging lens comprising:

a stop;
a first lens group;
a second lens group;
and
a third lens group, arranged in this order from an object side to an image plane side,
wherein said first lens group includes a first lens having positive refractive power, a second lens, and a third lens,
said second lens group includes a fourth lens and a fifth lens,
said third lens group includes a sixth lens and a seventh lens,
said first lens, said second lens, said third lens, said fourth lens, said fifth lens, said sixth lens, and said seventh lens are arranged on an optical axis with a space in between respectively,
said fifth lens is formed in a meniscus shape near an optical axis thereof,
said seventh lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius,
said surface of the seventh lens on the image plane side is formed in an aspheric shape having at least one inflexion point, and
said third lens has an Abbe's number νd3 and said seventh lens has a focal length f7 so that the following conditional expressions are satisfied:
20<νd3<35,
−4.0<f7/f<−0.8
where f is a focal length of a whole lens system.

13 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/900,973Filed 21 Feb 2018 · continuation
Priority: JP 2014-05741420 Mar 2014
Published: US 2018/0180846 A128 Jun 2018
Granted: 31 Dec 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G02B 9/64
Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -: having more…
G02B 9/12
Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -: having three…
G02B 13/0045
Having at least one aspherical surface: having five or more lenses
G02B 27/0025
Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00: for optical correction, e.g. distorsion,…

Family

Application14/572,832Parent of this continuation · filed 17 Dec 2014
Application15/275,557Parent of this continuation · filed 26 Sep 2016
US 9,541,730 B2Parent of this continuation · filed 10 Jan 2017
US 2018/0180846 A1Pre-grant publication · published 28 Jun 2018
US 9,933,597 B2Parent of this continuation
US 2015/0268448 A1Published application
US 2017/0010449 A1Published application
US 10,520,702 B2This patent

From the US filing history. Foreign family members aren’t listed.