# US 8,542,448 B2 · Imaging lens, imaging apparatus and portable terminal device

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- Number: US 8,542,448 B2
- Document ID: US8542448B2
- Status: Granted
- Kind: B2
- Application number: 13/682,451
- Filed: 2012-11-20
- Published: 2013-05-09
- Granted: 2013-09-24
- Earliest claimed: 2009-04-07
- Assignees: FUJIFILM Corporation
- Applicants: FUJIFILM Corporation
- Inventors: Yoshikazu Shinohara
- Web page: https://patentgrep.com/patent/US8542448B2

## CPC

- G02B 3/04: with continuous faces that are rotationally symmetrical but deviate from a true sphere {, e.g. so called "aspheric" lenses}
- G02B 3/00: Simple or compound lenses
- G02B 13/0045: {having five or more lenses}
- H04N 23/55: Optical parts specially adapted for electronic image sensors; Mounting thereof
- H04N 23/57: Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An imaging lens is provided and includes: in order from the object side, a first lens having a positive refractive power; a second lens having a negative refractive power; a third lens having a concave surface on the image side near the optical axis and having a positive refractive power; a fourth lens having a positive refractive power near the optical axis; and a fifth lens having a negative refractive power near the optical axis. An image side surface of the fifth lens is concave near the optical axis and has a region where a negative power of the region decreases toward a periphery of the fifth lens as compared with a negative power near the optical axis.

## Claims

### Claim 1

An imaging lens comprising: in order from an object side,
a first lens having a positive refractive power;
a second lens having a negative refractive power;
a third lens having a concave surface on an image side near an optical axis thereof and having a positive refractive power;
a fourth lens having a positive refractive power near the optical axis thereof; and
a fifth lens having a negative refractive power near the optical axis thereof, wherein an image side surface of the fifth lens is concave near the optical axis and has a region where a negative power of the region decreases toward a periphery of the fifth lens as compared with a negative power near the optical axis,
wherein the following conditional expression is further satisfied:
vd2<35 (4)
wherein vd2 is an Abbe number of the second lens at the d-line.

### Claim 2 (depends on 1)

The imaging lens according to claim 1, wherein an object side surface of the first lens is convex toward the object side near the optical axis, and an image side surface of the fourth lens is convex toward an image side near the optical axis.

### Claim 3 (depends on 1)

The imaging lens according to claim 1, wherein the fifth lens is biconcave near the optical axis.

### Claim 4 (depends on 1)

The imaging lens according to claim 1, wherein the following conditional expression is satisfied:
D7>D6 (1)
wherein D6 is a thickness of the third lens on the optical axis, and D7 is an air space between the third lens and the fourth lens on the optical axis.

### Claim 5 (depends on 1)

The imaging lens according to claim 1, wherein the following conditional expression is further satisfied:
0.8<f/f1<1.5 (2)
wherein f1 is a focal length of the first lens, and f is a focal length of the imaging system.

### Claim 6 (depends on 1)

The imaging lens according to claim 1, wherein the following conditional expression is further satisfied:
f1<|f2|<f3 (3)
wherein f1 is a focal length of the first lens, f2 is a focal length of the second lens, and f3 is a focal length of the third lens.

### Claim 7 (depends on 1)

The imaging lens according to claim 1, wherein the following conditional expression is satisfied:
f4<f1 (5A)
f4<|f21 (5B)
f4<f3 (5C)
wherein 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, and f4 is a focal length of the fourth lens.

### Claim 8 (depends on 1)

The imaging lens according to claim 1, wherein both surfaces in each of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are aspheric.

### Claim 9 (depends on 1)

The imaging lens according to claim 1, wherein an object side surface of the fifth lens is aspheric and has an inflection point in an effective diameter thereof.

### Claim 10 (depends on 1)

The imaging lens according to claim 1, wherein the image side surface of the fifth lens has an aspheric shape having an inflection point in the effective diameter thereof.

### Claim 11 (depends on 1)

The imaging lens according to claim 1, wherein the image side surface of the fifth lens is aspheric and has a local maximum or minimum point at a position other than the optical axis in the effective diameter thereof.

### Claim 12 (depends on 1)

An imaging apparatus comprising:
an imaging lens according to claim 1; and
an imaging device for outputting an imaging signal based on an optical image formed by the imaging lens.

### Claim 13 (depends on 12)

The imaging apparatus according to claim 12, wherein the imaging device has a pixel number of 2 mega or more and has a pixel pitch of 3 μm or less.

### Claim 14 (depends on 12)

A portable terminal device comprising:
an imaging apparatus according to claim 12; and
a display unit that displays an image taken by the imaging apparatus.