# US 9,753,248 B2 · Imaging lens and imaging apparatus

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,753,248 B2
- Document ID: US9753248B2
- Status: Granted
- Kind: B2
- Application number: 14/820,587
- Filed: 2015-08-07
- Published: 2015-12-03
- Granted: 2017-09-05
- Earliest claimed: 2013-02-28
- Assignees: FUJIFILM Corporation
- Applicants: FUJIFILM Corporation
- Inventors: Taro Asami
- Web page: https://patentgrep.com/patent/US9753248B2

## CPC

- G02B 9/60: having five components only
- G02B 9/34: having four components only
- G02B 13/0015: {characterised by the lens design}
- G02B 13/04: Reversed telephoto objectives
- 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

An imaging lens consists of five lenses of, in order from the object side, a negative first lens, a positive second lens, a negative third lens, a positive fourth lens, and a positive fifth lens. The following conditional expressions are satisfied: Nd3<1.75 (1); νd3<27 (2); 0.0≦(R3+R4)/(R3−R4) (4); and f12/f<1.5 (5), where Nd3 is a refractive index of the material of the third lens for d-line, νd3 is an Abbe number of the material of the third lens for d-line, R3 is a curvature radius of an object-side surface of the second lens, R4 is a curvature radius of an image-side surface of the second lens, f12 is a combined focal length of the first lens and the second lens, and f is a focal length of an entire system.

## Claims

### Claim 1

An imaging lens consisting of, in order from the object side:
a first lens having negative refractive power;
a second lens having positive refractive power;
a third lens having negative refractive power;
a fourth lens having positive refractive power; and
a fifth lens having positive refractive power, wherein the following conditional expressions are satisfied:
Nd3<1.75 (1);
νd3<27 (2);
0.0≦(R3+R4)/(R3−R4) (4); and
f12/f<1.5 (5), where
Nd3 is a refractive index of the material of the third lens for d-line,
νd3 is an Abbe number of the material of the third lens for d-line,
R3 is a curvature radius of an object-side surface of the second lens,
R4 is a curvature radius of an image-side surface of the second lens,
f12 is a combined focal length of the first lens and the second lens, and
f is a focal length of an entire system.

### Claim 2 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is satisfied:
0.0<R1/f (6), where
R1 is a curvature radius of an object-side surface of the first lens, and
f is a focal length of an entire system.

### Claim 3 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is satisfied:
−3.0<f1/f<−0.5 (7), where
f1 is a focal length of the first lens, and
f is a focal length of an entire system.

### Claim 4 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is satisfied:
−0.8<(R8+R9)/(R8−R9)<0.8 (8), where
R8 is a curvature radius of an object-side surface of the fourth lens, and
R9 is a curvature radius of an image-side surface of the fourth lens.

### Claim 5 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is satisfied:
−2.5<(R10+R11)/(R10−R11)<−0.4 (9), where
R10 is a curvature radius of an object-side surface of the fifth lens, and
R11 is a curvature radius of an image-side surface of the fifth lens.

### Claim 6 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is satisfied:
−2.0<f3/f<−0.2 (10), where
f3 is a focal length of the third lens, and
f is a focal length of an entire system.

### Claim 7 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is satisfied:
0.5<f4/f<2.5 (11), where
f4 is a focal length of the fourth lens, and
f is a focal length of an entire system.

### Claim 8 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is satisfied:
−3.5<f45/f3<−0.3 (12), where
f45 is a combined focal length of the fourth lens and the fifth lens, and
f3 is a focal length of the third lens.

### Claim 9 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is satisfied:
0.5<f345/f<4.0 (13), where
f345 is a combined focal length of the third lens, the fourth lens and the fifth lens, and
f is a focal length of an entire system.

### Claim 10 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is satisfied:
0.2<f12/f345<3.0 (14), where
f12 is a combined focal length of the first lens and the second lens, and
f345 is a combined focal length of the third lens, the fourth lens and the fifth lens.

### Claim 11 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is satisfied:
0.2<(DA+DB)/f<3.0 (15), where
DA is a center thickness of the second lens,
DB is an air space between the second lens and the third lens, and
f is a focal length of an entire system.

### Claim 12 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is satisfied:
−3.0<f1/f2<−0.6 (16), where
f1 is a focal length of the first lens, and
f2 is a focal length of the second lens.

### Claim 13 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is further satisfied:
Nd3<1.7 (1-1), where
Nd3 is a refractive index of the material of the third lens for d-line.

### Claim 14 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is further satisfied:
1.55<Nd3<1.7 (1-3), where
Nd3 is a refractive index of the material of the third lens for d-line.

### Claim 15 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is further satisfied:
νd3<26 (2-1), where
νd3 is an Abbe number of the material of the third lens for d-line.

### Claim 16 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is further satisfied:
19<νd3<26 (2-2), where
νd3 is an Abbe number of the material of the third lens for d-line.

### Claim 17 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is further satisfied:
0.02≦(R3+R4)/(R3−R4)<1.0 (4-5), where
R3 is a curvature radius of an object-side surface of the second lens, and
R4 is a curvature radius of an image-side surface of the second lens.

### Claim 18 (depends on 1)

The imaging lens, as defined in claim 1, wherein the following conditional expression is further satisfied:
1.0<f12/f<1.48 (5-4), where
f12 is a combined focal length of the first lens and the second lens, and
f is a focal length of an entire system.

### Claim 19 (depends on 2)

The imaging lens, as defined in claim 2, wherein the following conditional expression is further satisfied:
1.2<R1/f<5 (6-4), where
R1 is a curvature radius of an object-side surface of the first lens, and
f is a focal length of an entire system.

### Claim 20 (depends on 1)

An imaging apparatus comprising:
imaging lens, as defined in claim 1, which is mounted thereon.