US 8,477,435 B2Granted

Imaging lens

AssigneeOptical Logic Inc.

InventorsYoji Kubota, Kenichi Kubota, Hitoshi Hirano, Ichiro Kurihara, Yoshio Ise, Sumio Fukuda

Life of this patent

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Abstract

An imaging lens, although compact, has satisfactorily corrected aberrations. The imaging lens is configured by disposing, in sequence from the object side, a stop (ST); a first lens (L1), which has a double convex shape near the optical axis; a meniscus-shaped negative second lens (L2) which has near the optical axis a convex surface facing the object side; a meniscus-shaped positive third lens (L3) which has near the optical axis a concave surface facing the object side; and a positive fourth lens (L4) which has a double convex shape near the optical axis. In the configuration, the refractive power of the first lens (L1) is greater than the refractive power of each of the second lens (L2), the third lens (L3), and the fourth lens (L4).

Claims9

Dependent claims

An imaging lens comprising:

a first lens having positive refractive power;
a second lens having negative refractive power;
a third lens having positive refractive power;
and
a fourth lens having positive refractive power, said first to fourth lenses being arranged in an order from an object side to an image plane side,
wherein said first lens is formed in a shape so that a curvature radius of a surface thereof on the object side is positive,
said second lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are both positive,
said third lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are both negative, and
said fourth lens is formed in a shape so that a curvature radius of a surface thereof on the object side is positive, and a curvature radius of a surface thereof on the image plane side is negative.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/478,762Filed 23 May 2012 · continuation
Priority: JP 2009-26697325 Nov 2009
Published: US 2012/0229922 A113 Sep 2012
Granted: 2 Jul 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G02B 13/004
Having at least one aspherical surface: having four lenses
G02B 9/34
Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -: having four…
G02B 13/18
Optical objectives specially designed for the purposes specified below: with lenses having one or more non-spherical faces, e.g. for reducing…
G02B
Optical elements, systems or apparatus