US 10,761,296 B2 · Imaging lens

Abstract

There is provided an imaging lens which is compact and corresponds to wide field of view, and achieves excellent optical performance. An imaging lens comprises in order from an object side to an image side, a first lens having a convex surface facing an image side and positive refractive power, a second lens having a concave surface facing the image side near an optical axis and negative refractive power, a third lens having the convex surface facing the image side and the positive refractive power, and a fourth lens being a meniscus lens having the convex surface facing an object side near the optical axis and having the negative refractive power, wherein said fourth lens is a double-sided aspheric lens and has a pole point at an off-axial position on the image-side surface, and a below conditional expression (1) is satisfied: 0.5<Σd/TTL<0.9 (1) where Σd: distance along the optical axis from an object-side surface of the first lens to an image-side surface of the fourth lens, and TTL: total track length.

Claims18

Dependent claims

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

a first lens having concave surface facing the object side and a convex surface facing an image side, the first lens having positive refractive power,
a second lens having a concave surface facing the image side near an optical axis and negative refractive power,
a third lens having the convex surface facing the image side and the positive refractive power, and
a fourth lens being a meniscus lens having the convex surface facing an object side near the optical axis and having the negative refractive power, wherein said fourth lens is a double-sided aspheric lens and has a pole point at an off-axial position on the image-side surface, and below conditional expressions (1), (2) and (3) are satisfied:
0.5<Σd/TTL<0.9 (1)
0.7<|r5|/f<3.5 (2)
1.0<f1/f (3)
where
Σd:
distance along the optical axis from an object-side surface of the first lens to an image-side surface of the fourth lens,
TTL:
total track length,
r5:
curvature radius near the optical axis of the object-side surface of the third lens,
f1:
focal length of the first lens, and
f:
focal length of an overall optical system.

15 more elements

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

a first lens having a concave surface facing the object side and a convex surface facing an image side, and positive refractive power,
a second lens having a concave surface facing the image side near an optical axis and negative refractive power,
a third lens having the convex surface facing the image side and the positive refractive power, and
a fourth lens being a meniscus lens having the convex surface facing an object side near the optical axis and having the negative refractive power, wherein said fourth lens is a double-sided aspheric lens and has a pole point at an off-axial position on the image-side surface, and below conditional expressions (1), (4), (5) and (12) are satisfied:
0.5<Σd/TTL<0.9 (1)
30<νd1−νd2 (4)
20<νd4<32 (5)
−8.5<═r5═/r6<3.0 (12)
where
Σd:
distance along the optical axis from the object-side surface of the first lens to the image-side surface of the fourth lens,
TTL:
total track length,
νd1:
abbe number at d-ray of the first lens,
νd2:
abbe number at d-ray of the second lens,
νd4:
abbe number at d-ray of a fourth lens,
r5:
curvature radius near the optical axis of the object-side surface of the third lens, and
r6:
curvature radius near the optical axis of the image-side surface of the third lens.

20 more elements

Dependencies are inferred from the claim text.

Imaging lens

Life of this patent

Imaging lens

Life of this patent

Abstract

Claims18