# US 10,481,365 B2 · Optical system

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- Number: US 10,481,365 B2
- Document ID: US10481365B2
- Status: Granted
- Kind: B2
- Application number: 15/069,520
- Filed: 2016-03-14
- Published: 2017-02-16
- Granted: 2019-11-19
- Earliest claimed: 2015-08-10
- Assignees: Samsung Electro-Mechanics Co., Ltd.
- Applicants: Samsung Electro-Mechanics Co., Ltd.
- Inventors: Il Yong Park
- Web page: https://patentgrep.com/patent/US10481365B2

## CPC

- G02B 13/0045: {having five or more lenses}
- G02B 9/62: having six components only
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An optical system includes a first lens including a positive refractive power, a second lens including a positive refractive power and a convex image-side surface, a third lens, and a fourth lens. The optical system includes a fifth lens including a concave object-side surface and a concave image-side surface, and a sixth lens including an inflection point formed on an image-side surface thereof. The first to sixth lenses are sequentially disposed from an object toward an imaging plane.

## Claims

### Claim 1

An optical system, comprising:
a first lens comprising a positive refractive power;
a second lens comprising a positive refractive power and a convex image-side surface in a paraxial region;
a third lens;
a fourth lens;
a fifth lens comprising a concave object-side surface in a paraxial region and a concave image-side surface in the paraxial region; and
a sixth lens comprising an inflection point formed on an image-side surface thereof,
wherein the first to sixth lenses are sequentially disposed from an object toward an imaging plane,
f, an overall focal length of the optical system, and f1, a focal length of the first lens, satisfy 1.0<f1/f<1.8,
f, and f5 a focal length of the fifth lens, satisfy f5/f<−10;
f2, a focal length of the second lens, and, f3, a focal length of the third lens satisfy −1.2<f2/f3<0, and
f, and r10, a radius of curvature of an image-side surface of the fifth lens, satisfy 30<r10/f.

### Claim 2 (depends on 1)

The optical system of claim 1, wherein, V1, an Abbe number of the first lens and, V2, an Abbe number of the second lens satisfy V1-V2<25.

### Claim 3 (depends on 1)

The optical system of claim 1, wherein, f, an overall focal length of the optical system and, f2, a focal length of the second lens satisfy 0.5<f2/f<2.0.

### Claim 4 (depends on 1)

The optical system of claim 1, wherein, f, an overall focal length of the optical system and, f3, a focal length of the third lens satisfy −3<f3/f<−1.

### Claim 5 (depends on 1)

The optical system of claim 1, wherein, f, an overall focal length of the optical system and, f4, a focal length of the fourth lens satisfy 3<1f4/f1.

### Claim 6 (depends on 1)

The optical system of claim 1, wherein, f1, a focal length of the first lens and, f2, a focal length of the second lens satisfy 0.5<f1/f2<2.0.

### Claim 7 (depends on 1)

The optical system of claim 1, wherein, f, an overall focal length of the optical system and, r6, a radius of curvature of an image-side surface of the third lens satisfy 0.3<r6/f<1.4.

### Claim 8 (depends on 1)

The optical system of claim 1, wherein, EPD, a diameter of an entrance pupil of the optical system and, f12, a synthetic focal length of the first lens and the second lens satisfy 0.18<(EPD/2)/f12.

### Claim 9

An optical system, comprising:
a first lens comprising a positive refractive power;
a second lens comprising a convex image-side surface in a paraxial region;
a third lens comprising a convex object-side surface in the paraxial region;
a fourth lens comprising a convex image-side surface in the paraxial region;
a fifth lens comprising a concave object-side surface in the paraxial region and a concave image-side surface in the paraxial region; and
a sixth lens comprising an inflection point formed on an image-side surface thereof,
wherein the first to sixth lenses are sequentially disposed from an object toward an imaging plane,
f, an overall focal length of the optical system, and f1, a focal length of the first lens, satisfy 1.0<f1/f<1.8,
f, and f5 a focal length of the fifth lens, satisfy f5/f<−10;
f2, a focal length of the second lens, and, f3, a focal length of the third lens satisfy −1.2<f2/f3<0,
f, and r10, a radius of curvature of an image-side surface of the fifth lens, satisfy 30<r10/f.

### Claim 10 (depends on 9)

The optical system of claim 9, wherein the first lens comprises a convex object-side surface and a concave image-side surface.

### Claim 11 (depends on 9)

The optical system of claim 9, wherein the second lens comprises a convex object-side surface.

### Claim 12 (depends on 9)

The optical system of claim 9, wherein the third lens comprises a concave image-side surface.

### Claim 13 (depends on 9)

The optical system of claim 9, wherein the fourth lens comprises a concave object-side surface.

### Claim 14 (depends on 9)

The optical system of claim 9, wherein the sixth lens comprises a convex object-side surface and a concave image-side surface.

### Claim 15

An optical system, comprising:
a first lens;
a second lens comprising a convex image-side surface in a paraxial region;
a third lens comprising a convex object-side surface in the paraxial region;
a fourth lens comprising a convex image-side surface in the paraxial region;
a fifth lens comprising a concave object-side surface in the paraxial region and a concave image-side surface in the paraxial region; and
a sixth lens comprising an inflection point formed on an image-side surface thereof, wherein
the second lens has a same refractive index as a refractive index of the first lens,
the third lens, the fourth lens, and the fifth lens have a refractive index higher than the refractive indexes of the first and second lenses, and
the sixth lens has a refractive index lower than the refractive indexes of the first and second lenses,
f, an overall focal length of the optical system, and f1, a focal length of the first lens, satisfy 1.0<f1/f<1.8,
f, and f5 a focal length of the fifth lens, satisfy f5/f<−10;
f2, a focal length of the second lens, and, f3, a focal length of the third lens satisfy −1.2<f2/f3<0, and
f, and r10, a radius of curvature of an image-side surface of the fifth lens, satisfy 30<r10/f.

### Claim 16 (depends on 15)

The optical system of claim 15, wherein, V1, an Abbe number of the first lens, V2, an Abbe number of the second lens, V3, an Abbe number of the third lens, and, V5, an Abbe number of the fifth lens satisfy
V1−V2<25,
15<|V1−V3|, and
25<V1−V5<45.

### Claim 17 (depends on 15)

The optical system of claim 15, wherein, f, an overall focal length of the optical system, and TTL a distance from the object-side surface of the first lens to an imaging plane satisfy TTL/f<1.5.

### Claim 18 (depends on 15)

The optical system of claim 15, wherein, f, an overall focal length of the optical system, and, BFL, a distance from an object-side surface of the sixth lens to an imaging plane satisfy BFL/f<0.5.

### Claim 19 (depends on 15)

The optical system of claim 15, wherein, f, an overall focal length of the optical system, and, D2, a distance from the image-side surface of the first lens to an object-side surface of the second lens satisfy D2/f<0.1.

### Claim 20 (depends on 15)

The optical system of claim 15, wherein, FOV, a field of view of the optical system satisfy 75<FOV.