# US 9,519,121 B2 · Imaging lens and imaging apparatus

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- Number: US 9,519,121 B2
- Document ID: US9519121B2
- Status: Granted
- Kind: B2
- Application number: 14/641,915
- Filed: 2015-03-09
- Published: 2015-09-17
- Granted: 2016-12-13
- Earliest claimed: 2014-03-12
- Assignees: FUJIFILM Corporation
- Applicants: FUJIFILM Corporation
- Inventors: Hiromitsu Yamakawa
- Web page: https://patentgrep.com/patent/US9519121B2

## CPC

- G02B 9/04: having two components only
- G02B 13/0045: {having five or more lenses}
- G02B 13/06: Panoramic objectives; So-called "sky lenses" {including panoramic objectives having reflecting surfaces}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

The imaging lens consists essentially of a front group that consist essentially of a negative first lens having a meniscus shape with a convex surface toward the object side, a negative second lens and a positive third lens; a stop; a positive rear group that includes a positive lens and a negative lens. When the focal length of the entire system is f, a half angle of view is ω, and the distance from the object-side surface of the first lens to the imaging plane along the optical axis is L, conditional formula (1) below is satisfied: 0.25<2*f*tan(ω/2)/L<1.00 (1).

## Claims

### Claim 1

An imaging lens, consisting of:
a front group which consists of a negative first lens having a meniscus shape with a convex surface toward the object side, a negative second lens, a point along the optical axis at the image-side surface of which is more toward the object side than points on both ends of the effective diameter of the image-side surface, and a positive third lens;
an aperture stop; and
a rear group which is positive as a whole in this order from the object side, wherein
the rear group consists of one positive lens and one negative lens; and
conditional formula (1) below is satisfied:
0.25<2*f*tan(ω/2)/L<1.00 (1),
where
f: the focal length of the entire system
ω: a half angle of view
L: the distance from the object-side surface of the first lens to the imaging plane along the optical axis (back focus corresponds to an air converted length), and
the conditional formula (2) below is satisfied:
−2.0<f2/f<−0.5 (2),
where
f2: the focal length of the second lens, and
f: the focal length of the entire system.

### Claim 2 (depends on 1)

The imaging lens of claim 1 that satisfies conditional formula (3) below:
1.0<f3/f<3.0 (3),
where
f3: the focal length of the third lens, and
f: the focal length of the entire system.

### Claim 3 (depends on 1)

The imaging lens of claim 1 that satisfies conditional formula (5) below:
−20.0<fN/fP<−0.9 (5),
where
fN: the focal length of the negative lens of the rear group,
fP: the focal length of the positive lens of the rear group.

### Claim 4 (depends on 1)

The imaging lens of claim 1 that satisfies conditional formula (1-1) below:
0.27<2*f*tan(ω/2)/L<1.00 (1-1),
where
f: the focal length of the entire system,
ω: a half angle of view
L: the distance from the object-side surface of the first lens to the imaging plane along the optical axis (the back focus corresponds to an air converted length).

### Claim 5 (depends on 1)

The imaging lens of claim 1 that satisfies conditional formula (2-1) below:
−1.9<f2/f<−0.7 (2-1),
where
f2: the focal length of the second lens, and
f: the focal length of the entire system.

### Claim 6 (depends on 1)

The imaging lens of claim 1 that satisfies conditional formula (3-1) below:
1.0<f3/f<2.7 (3-1),
where
f3: the focal length of the third lens, and
f: the focal length of the entire system.

### Claim 7 (depends on 1)

The imaging lens of claim 1 that satisfies conditional formula (4-1) below:
d4/L<0.06 (4-1),
where
d4: the distance from the second lens to the third lens along the optical axis, and
L: the distance from the object-side surface of the first lens to the imaging plane along the optical axis (the back focus corresponds to an air converted length).

### Claim 8 (depends on 1)

The imaging lens of claim 1 that satisfies conditional formula (5-1) below:
−9.0<fN/fP<−1.0 (5-1),
where
fN: the focal length of the negative lens of the rear group, and
fP: the focal length of the positive lens of the rear group.

### Claim 9 (depends on 1)

The imaging lens of claim 1, wherein the third lens is of a shape with a convex surface toward the object side.

### Claim 10 (depends on 1)

An imaging apparatus comprising:
the imaging lens of claim 1.

### Claim 11

An imaging lens, consisting of:
a front group which consists of a negative first lens having a meniscus shape with a convex surface toward the object side, a negative second lens, a point along the optical axis at the image-side surface of which is more toward the object side than points on both ends of the effective diameter of the image-side surface, and a positive third lens;
an aperture stop; and
a rear group which is positive as a whole in this order from the object side, wherein
the rear group consists of one positive lens and one negative lens; and
conditional formula (1) below is satisfied:
0.25<2*f*tan(ω/2)/L<1.00 (1),
where
f: the focal length of the entire system
ω: a half angle of view
L: the distance from the object-side surface of the first lens to the imaging plane along the optical axis (back focus corresponds to an air converted length), and
the conditional formula (4) below is satisified:
d4/L<0.07 (4),
where
d4: the distance from the second lens to the third lens along the optical axis, and
L: the distance from the object-side surface of the first lens to the imaging plane along the optical axis (the back focus corresponds to an air converted length).