# US 9,753,256 B2 · Imaging lens and imaging apparatus

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- Number: US 9,753,256 B2
- Document ID: US9753256B2
- Status: Granted
- Kind: B2
- Application number: 14/858,419
- Filed: 2015-09-18
- Published: 2016-01-14
- Granted: 2017-09-05
- Earliest claimed: 2013-03-26
- Assignees: FUJIFILM Corporation
- Applicants: FUJIFILM Corporation
- Inventors: Taro Asami; Yu Kitahara
- Web page: https://patentgrep.com/patent/US9753256B2

## CPC

- G02B 13/0045: {having five or more lenses}
- G02B 9/62: having six components only
- G02B 13/04: Reversed telephoto objectives
- 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 9/00: Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - (G02B15/00 takes precedence)
- G02B 13/001: {Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras (G02B23/243 takes precedence)}
- G02B 13/002: {having at least one aspherical surface}
- 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, in order from the object side, a negative first lens, a positive second lens, a positive third lens, a negative fourth lens, a positive fifth lens, and a positive sixth lens. The imaging lens satisfies the condition expressions below: f1/f<−1.68 (1-2), −0.7<f4/f (2), −0.6<(R3+R4)/(R3−R4)<2.2 (11-2), and 0.5<f2/f3<4.0 (12), where f1 to f4 are focal lengths of the first to the fourth lenses, f is a focal length of the entire system, R3 is a radius of curvature of the object-side surface of the second lens, and R4 is a radius of curvature of the image-side surface of the second lens.

## Claims

### Claim 1

An imaging lens consisting of, in order from an object side, a first lens having a negative power, a second lens having a positive power, a third lens having a positive power, a fourth lens having a negative power, a fifth lens having a positive power, and a sixth lens having a positive power, wherein the condition expressions below are satisfied:
f1/f<−1.68 (1-2),
−0.7<f4/f (2),
1<f12/f<25 (10),
−0.6<(R3+R4)/(R3−R4)<2.2 (11-2), and
0.5<f2/f3<4.0 (12),
where f1 is a focal length of the first lens, f2 is a focal length of the second lens, f3 is a focal length of the third lens, f4 is a focal length of the fourth lens, R3 is a radius of curvature of an object-side surface of the second lens, R4 is a radius of curvature of an image-side surface of the second lens, f is a focal length of the entire system, and f12 is a combined focal length of the first lens and the second lens.

### Claim 2 (depends on 1)

The imaging lens as claimed in claim 1, wherein the first lens is made of a material having an Abbe number with respect to the d-line of 40 or more, the second lens is made of a material having an Abbe number with respect to the d-line of 55 or more, the third lens is made of a material having an Abbe number with respect to the d-line of 30 or more, the fourth lens is made of a material having an Abbe number with respect to the d-line of 25 or less, the fifth lens is made of a material having an Abbe number with respect to the d-line of 30 or more, and the sixth lens is made of a material having an Abbe number with respect to the d-line of 30 or more.

### Claim 3 (depends on 1)

The imaging lens as claimed in claim 1, wherein the condition expression below is satisfied:
1.8<(R1+R2)/(R1−R2) (7),
where R1 is a radius of curvature of an object-side surface of the first lens, and R2 is a radius of curvature of an image-side surface of the first lens.

### Claim 4 (depends on 1)

The imaging lens as claimed in claim 1, wherein the condition expression below is satisfied:
(R5+R6)/(R5−R6)<0.0 (8),
where R5 is a radius of curvature of an object-side surface of the third lens, and R6 is a radius of curvature of an image-side surface of the third lens.

### Claim 5 (depends on 1)

The imaging lens as claimed in claim 1, wherein the condition expression below is satisfied:
3.0<(R10+R11)/(R10−R11)<13.5 (9),
where R10 is a radius of curvature of an object-side surface of the fifth lens, and R11 is a radius of curvature of an image-side surface of the fifth lens.

### Claim 6 (depends on 1)

The imaging lens as claimed in claim 1, wherein the condition expression below is satisfied:
0.2<f5/f6<4.0 (13),
where f5 is a focal length of the fifth lens, and f6 is a focal length of the sixth lens.

### Claim 7 (depends on 1)

The imaging lens as claimed in claim 1, wherein the condition expression below is satisfied:
0.4<f6/f<4.0 (14),
where f is a focal length of the entire system, and f6 is a focal length of the sixth lens.

### Claim 8 (depends on 1)

The imaging lens as claimed in claim 1, wherein an aperture stop is disposed between an image-side surface of the fourth lens and an object-side surface of the second lens.

### Claim 9 (depends on 1)

The imaging lens as claimed in claim 1, wherein the condition expression below is further satisfied:
−0.62<f4/f (2-2),
where f4 is a focal length of the fourth lens, and f is a focal length of the entire system.

### Claim 10 (depends on 1)

The imaging lens as claimed in claim 1, wherein the condition expression below is further satisfied:
−0.70<f4/f<−0.3 (2-3),
where f4 is a focal length of the fourth lens, and f is a focal length of the entire system.

### Claim 11 (depends on 1)

An imaging apparatus comprising the imaging lens as claimed in claim 1.

### Claim 12 (depends on 1)

The imaging lens as claimed in claim 1, wherein the conditional expression below is further satisfied:
−0.5<(R3+R4)/(R3−R4)<2.2 (11-4).

### Claim 13

An imaging lens consisting of, in order from an object side, a first lens having a negative power, a second lens having a positive power, a third lens having a positive power, a fourth lens having a negative power, a fifth lens having a positive power, and a sixth lens having a positive power, wherein the condition expressions below are satisfied:
2.4<f1/f4 (3),
0.0<f3/f<2.0 (4), and
3.2<νd6/νd4 (6),
where f is a focal length of the entire system, f1 is a focal length of the first lens, f3 is a focal length of the third lens, f4 is a focal length of the fourth lens, νd4 is an Abbe number with respect to the d-line of a material forming the fourth lens, and νd6 is an Abbe number with respect to the d-line of a material forming the sixth lens.

### Claim 14 (depends on 13)

The imaging lens as claimed in claim 13, wherein the condition expression below is satisfied:
−0.8<(R3+R4)/(R3−R4)<3.5 (11),
where R3 is a radius of curvature of an object-side surface of the second lens, and R4 is a radius of curvature of an image-side surface of the second lens.

### Claim 15 (depends on 13)

The imaging lens as claimed in claim 13, wherein the condition expression below is satisfied:
0.5<f2/f3<4.0 (12),
where f2 is a focal length of the second lens, and f3 is a focal length of the third lens.

### Claim 16 (depends on 13)

The imaging lens as claimed in claim 13, wherein the condition expression below is further satisfied:
2.8<f1/f4<15.0 (3-6),
where f1 is a focal length of the first lens, and f4 is a focal length of the fourth lens.

### Claim 17

An imaging lens consisting of, in order from an object side, a first lens having a negative power, a second lens having a positive power, a third lens having a positive power, a fourth lens having a negative power, a fifth lens having a positive power, and a sixth lens having a positive power, wherein the condition expression below is satisfied:
3.0<νd2/νd4 (5),
where νd2 is an Abbe number with respect to the d-line of a material forming the second lens, and νd4 is an Abbe number with respect to the d-line of a material forming the fourth lens.

### Claim 18 (depends on 17)

The imaging lens as claimed in claim 17, wherein the condition expression below is further satisfied:
3.0<νd2/νd4<4.5 (5-2),
where νd2 is an Abbe number with respect to the d-line of a material forming the second lens, and νd4 is an Abbe number with respect to the d-line of a material forming the fourth lens.

### Claim 19

An imaging lens consisting of, in order from an object side, a first lens having a negative power, a second lens having a positive power, a third lens having a positive power, a fourth lens having a negative power, a fifth lens having a positive power, and a sixth lens having a positive power, wherein the second lens is made of a material having an Abbe number with respect to the d-line of 55 or more, and the condition expression below is satisfied:
3.2<νd6/νd4 (6),
where νd4 is an Abbe number with respect to the d-line of a material forming the fourth lens, and νd6 is an Abbe number with respect to the d-line of a material forming the sixth lens.

### Claim 20

An imaging lens consisting of, in order from an object side, a first lens having a negative power, a second lens having a positive power, a third lens having a positive power, a fourth lens having a negative power, a fifth lens having a positive power, and a sixth lens having a positive power, wherein the condition expressions below are satisfied:
f1/f<−1.68 (1-2),
−0.7<f4/f (2),
0.3<f23/f56<3.0 (15),
−0.6<(R3+R4)/(R3−R4)<2.2 (11-2), and
0.5<f2/f3<4.0 (12),
where f1 is a focal length of the first lens, f2 is a focal length of the second lens, f3 is a focal length of the third lens, f4 is a focal length of the fourth lens, R3 is a radius of curvature of an object-side surface of the second lens, R4 is a radius of curvature of an image-side surface of the second lens, f is a focal length of the entire system, f23 is a combined focal length of the second lens and the third lens, and f56 is a combined focal length of the fifth lens and the sixth lens.