US 2019/0377160 A1Published application

Imaging lens

AssigneeKantatsu Co., Ltd.

InventorsYukio SEKINE, Masaya HASHIMOTO

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Abstract

There is provided an imaging lens with high-resolution which satisfies demand of the wide field of view, the low-profileness and the low F-number, and excellently corrects aberrations. An imaging lens comprises in order from an object side to an image side, a first lens having positive refractive power and a convex surface facing the object side near the optical axis, a second lens having negative refractive power near the optical axis, a third lens having the positive refractive power near the optical axis, a fourth lens, and a fifth lens having the negative refractive power and a concave surface facing the image side near the optical axis, wherein the image-side surface of said fifth lens is formed as an aspheric surface having at least one off-axial pole point, and predetermined conditional expressions are satisfied.

Claims20

Dependent claims

An imaging lens comprising in order from an object side to an image side,

a first lens having positive refractive power and a convex surface facing the object side near the optical axis,
a second lens having negative refractive power near the optical axis,
a third lens having the positive refractive power near the optical axis,
a fourth lens, and
a fifth lens having the negative refractive power and a concave surface facing the image side near the optical axis, wherein the image-side surface of said fifth lens is formed as an aspheric surface having at least one off-axial pole point, and below conditional expressions (1), (2) and (3) are satisfied:
0.15<vd4/vd5<0.55 (1)
0.7<T1/T2<3.0 (2)
1.1<|r7|/r8 (3)
where
vd4:
abbe number at d-ray of the fourth lens,
vd5:
abbe number at d-ray of the fifth lens,
T1:
distance along the optical axis from the image-side surface of the first lens to the object-side surface of the second lens,
T2:
distance along the optical axis from the image-side surface of the second lens to the object-side surface of the third lens,
r7:
paraxial curvature radius of the object-side surface of the fourth lens,
r8:
paraxial curvature radius of the image-side surface of the fourth lens.

18 more elements

An imaging lens comprising in order from an object side to an image side,

a first lens having positive refractive power and a convex surface facing the object side near the optical axis,
a second lens having negative refractive power near the optical axis,
a third lens having the positive refractive power near the optical axis,
a fourth lens, and
a fifth lens having the negative refractive power and a concave surface facing the image side near the optical axis, wherein the image-side surface of said fifth lens is formed as an aspheric surface having at least one off-axial pole point, the object-side surface of said third lens is the concave surface facing the object side near the optical axis, the object-side surface of said fifth lens is the convex surface near the optical axis, and below conditional expressions (4) and (5) are satisfied:
6<(T1/f)×100<18 (4)
1.6<|r7|/f (5)
where
T1:
distance along the optical axis from the image-side surface of the first lens to the object-side surface of the second lens,
f:
focal length of the overall optical system of the imaging lens,
r7:
paraxial curvature radius of the object-side surface of the fourth lens.

11 more elements

Dependencies are inferred from the claim text.