# US 2021/0278638 A1 · Imaging lens

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- Number: US 2021/0278638 A1
- Document ID: US20210278638A1
- Status: Published application
- Kind: A1
- Application number: 17/328,702
- Filed: 2021-05-24
- Published: 2021-09-09
- Earliest claimed: 2013-05-31
- Assignees: Kantatsu Co., Ltd.
- Applicants: Kantatsu Co., Ltd.
- Inventors: Yukio SEKINE
- Web page: https://patentgrep.com/patent/US20210278638A1

## CPC

- G02B 13/0045: {having five or more lenses}
- G02B 9/62: having six components only
- G02B 27/0025: {for optical correction, e.g. distorsion, aberration}
- G02B 3/04: with continuous faces that are rotationally symmetrical but deviate from a true sphere {, e.g. so called "aspheric" lenses}
- G02B 5/005: {Diaphragms (for cameras G03B9/02)}
- G02B 13/0015: {characterised by the lens design}
- G02B 13/002: {having at least one aspherical surface}
- G02B 13/16: for use in conjunction with image converters or intensifiers {, or for use with projectors, e.g. objectives for projection TV}
- G02B 13/18: with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration {(G02B13/002 takes precedence)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A compact high-resolution imaging lens which provides a wide field of view of 80 degrees or more and corrects various aberrations properly. Designed for a solid-state image sensor, the imaging lens includes constituent lenses arranged in the following order from an object side to an image side: a first positive (refractive power) lens having a convex object-side surface; a second negative lens having a concave image-side surface; a third positive lens as a double-sided aspheric lens having a convex object-side surface; a fourth positive lens having a convex image-side surface; a fifth lens as a double-sided aspheric lens having a concave image-side surface; and a sixth negative lens having a concave image-side surface. The image-side surface of the sixth lens has an aspheric shape with a pole-change point in a position off an optical axis.

## Claims

### Claim 1

An imaging lens for a solid-state image sensor in which elements are arranged in order from an object side to an image side, comprising:
a first lens with positive refractive power having a convex surface on the object side;
a second lens with negative refractive power having a concave surface on the image side;
a third lens with positive refractive power as a double-sided aspheric lens having a convex surface on the object side;
a fourth lens with positive refractive power having a convex surface on the image side;
a fifth lens as a double-sided aspheric lens having a concave surface on the image side; and
a sixth lens with negative refractive power having a concave surface on the image side,
wherein the image-side surface of the sixth lens has an aspheric shape with a pole-change point in a position off an optical axis.

### Claim 2 (depends on 1)

The imaging lens according to claim 1,
wherein a conditional expression (11) below is satisfied:
0.8<ih/f<1.2 (11)
where
f: focal length of an overall optical system of the imaging lens
ih: maximum image height.

### Claim 3 (depends on 1)

The imaging lens according to claim 1,
wherein a conditional expression (9) below is satisfied:
0.65<Σd/TTL<0.90 (9)
where
TTL: distance on the optical axis from an object-side surface of an optical element located nearest to an object to an image plane without a filter, etc.
Σd: distance on the optical axis from the object-side surface of the first lens to the image-side surface of the sixth lens.

### Claim 4 (depends on 3)

The imaging lens according to claim 3,
wherein a conditional expression (10) below is satisfied:
TTL/f<1.6 (10)
where
TTL: distance on the optical axis from an object-side surface of an optical element located nearest to an object to an image plane without a filter, etc.
f: focal length of an overall optical system of the imaging lens.

### Claim 5 (depends on 1)

The imaging lens according to claim 1,
wherein:
the fifth lens is a meniscus lens with negative refractive power and the object-side surface and the image-side surface of the fifth lens have an aspheric shape with a pole-change point in a position off the optical axis; and
the sixth lens is a meniscus lens and the object-side surface of the sixth lens has an aspheric shape with a pole-change point in a position off the optical axis.

### Claim 6 (depends on 1)

The imaging lens according to claim 1,
wherein a conditional expression (1) below is satisfied:
0.55<f1/f<1.7 (1)
where
f1: focal length of the first lens
f: focal length of an overall optical system of the imaging lens.

### Claim 7 (depends on 6)

The imaging lens according to claim 6,
wherein a conditional expression (2) below is satisfied:
−2.3<f2/f<−0.8 (2)
where
f2: focal length of the second lens
f: focal length of an overall optical system of the imaging lens.

### Claim 8 (depends on 7)

The imaging lens according to claim 7,
wherein a conditional expression (12) below is satisfied:
1.3<f3/f<7.0 (12)
where
f3: focal length of the third lens
f: focal length of an overall optical system of the imaging lens.

### Claim 9 (depends on 1)

The imaging lens according to claim 1,
wherein conditional expressions (3) and (4) below are satisfied:
45<νd1<80 (3)
20<νd2<40 (4)
where
νd1: Abbe number of the first lens at d-ray
νd2: Abbe number of the second lens at d-ray.

### Claim 10 (depends on 1)

The imaging lens according to claim 1,
wherein conditional expressions (5) to (8) below are satisfied:
50<νd3<75 (5)
50<νd4<75 (6)
20<νd5<40 (7)
50<νd6<75 (8)
where
νd3: Abbe number of the third lens at d-ray
νd4: Abbe number of the fourth lens at d-ray
νd5: Abbe number of the fifth lens at d-ray
νd6: Abbe number of the sixth lens at d-ray.

### Claim 11 (depends on 2)

The imaging lens according to claim 2,
wherein a conditional expression (9) below is satisfied:
0.65<Σd/TTL<0.90 (9)
where
TTL: distance on the optical axis from an object-side surface of an optical element located nearest to an object to an image plane without a filter, etc.
Σd: distance on the optical axis from the object-side surface of the first lens to the image-side surface of the sixth lens.

### Claim 12 (depends on 11)

The imaging lens according to claim 11,
wherein a conditional expression (10) below is satisfied:
TTL/f<1.6 (10)
where
TTL: distance on the optical axis from an object-side surface of an optical element located nearest to an object to an image plane without a filter, etc.
f: focal length of an overall optical system of the imaging lens.

### Claim 13 (depends on 2)

The imaging lens according to claim 2,
wherein:
the fifth lens is a meniscus lens with negative refractive power and the object-side surface and the image-side surface of the fifth lens have an aspheric shape with a pole-change point in a position off the optical axis; and
the sixth lens is a meniscus lens and the object-side surface of the sixth lens has an aspheric shape with a pole-change point in a position off the optical axis.

### Claim 14 (depends on 2)

The imaging lens according to claim 2,
wherein a conditional expression (1) below is satisfied:
0.55<f1/f<1.7 (1)
where
f1: focal length of the first lens
f: focal length of an overall optical system of the imaging lens.

### Claim 15 (depends on 14)

The imaging lens according to claim 14,
wherein a conditional expression (2) below is satisfied:
−2.3<f2/f<−0.8 (2)
where
f2: focal length of the second lens
f: focal length of an overall optical system of the imaging lens.

### Claim 16 (depends on 15)

The imaging lens according to claim 15,
wherein a conditional expression (12) below is satisfied:
1.3<f3/f<7.0 (12)
where
f3: focal length of the third lens
f: focal length of an overall optical system of the imaging lens.

### Claim 17 (depends on 2)

The imaging lens according to claim 2,
wherein conditional expressions (3) and (4) below are satisfied:
45<νd1<80 (3)
20<νd2<40 (4)
where
νd1: Abbe number of the first lens at d-ray
νd2: Abbe number of the second lens at d-ray.

### Claim 18 (depends on 2)

The imaging lens according to claim 2,
wherein conditional expressions (5) to (8) below are satisfied:
50<νd3<75 (5)
50<νd4<75 (6)
20<νd5<40 (7)
50<νd6<75 (8)
where
νd3: Abbe number of the third lens at d-ray
νd4: Abbe number of the fourth lens at d-ray
νd5: Abbe number of the fifth lens at d-ray
νd6: Abbe number of the sixth lens at d-ray.

### Claim 19 (depends on 8)

The imaging lens according to claim 8,
wherein conditional expressions (5) to (8) below are satisfied:
50<νd3<75 (5)
50<νd4<75 (6)
20<νd5<40 (7)
50<νd6<75 (8)
where
νd3: Abbe number of the third lens at d-ray
νd4: Abbe number of the fourth lens at d-ray
νd5: Abbe number of the fifth lens at d-ray
νd6: Abbe number of the sixth lens at d-ray.

### Claim 20 (depends on 16)

The imaging lens according to claim 16,
wherein conditional expressions (5) to (8) below are satisfied:
50<νd3<75 (5)
50<νd4<75 (6)
20<νd5<40 (7)
50<νd6<75 (8)
where
νd3: Abbe number of the third lens at d-ray
νd4: Abbe number of the fourth lens at d-ray
νd5: Abbe number of the fifth lens at d-ray
νd6: Abbe number of the sixth lens at d-ray.