# US 8,570,664 B2 · Zoom lens system

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- Number: US 8,570,664 B2
- Document ID: US8570664B2
- Status: Granted
- Kind: B2
- Application number: 13/340,695
- Filed: 2011-12-30
- Published: 2013-05-30
- Granted: 2013-10-29
- Earliest claimed: 2011-11-25
- Assignees: HONG FU JIN PRECISION INDUSTRY (ShenZhen) CO., LTD.; Hong Hai Precision Industry Co., Ltd.
- Applicants: Hai-Jo Huang; Fang-Ying Peng; Sheng-An Wang; An-Tze Lee; Xiao-Na Liu
- Inventors: Hai-Jo Huang; Fang-Ying Peng; Sheng-An Wang; An-Tze Lee; Xiao-Na Liu
- Web page: https://patentgrep.com/patent/US8570664B2

## CPC

- G02B 15/143507: {arranged -++}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A zoom lens system includes a first lens group of negative refractive power, a second lens group of positive refractive power and a third lens group of positive refractive power. The zoom lens system satisfies the following condition formulas: 0.78<|f2/f1|<0.91, and 0.72<L2/fT<0.87, where f1 represents an effective focal length of the first lens group, f2 represents an effective focal length of the second lens group, L2 is a displacement of the second lens group when the zoom lens system varies from a wide-angle state to a telephoto state, and fT represents an effective focal length of the zoom lens system which is in the telephoto state.

## Claims

### Claim 1

A zoom lens system, in order from an object-side to an image-side thereof, comprising:
a first lens group of negative refractive power, the first lens group comprising, in the order from the object-side to the image-side of the zoom lens system, a first lens of negative refractive power and a second lens of positive refractive power;
a second lens group of positive refractive power, the second lens group comprising, in the order from the object-side to the image-side of the zoom lens system, a third lens of positive refractive power, a fourth lens of positive refractive power, a fifth lens of negative refractive power, and a sixth lens of negative refractive power; and
a third lens group of positive refractive power;
the zoom lens system satisfying the following condition formulas:
0.78<|f2/f1|<0.91, and
0.72<L2/fT<0.87,
where f1 represents an effective focal length of the first lens group, f2 represents an effective focal length of the second lens group, L2 is a displacement of the second lens group when the zoom lens system varies from a wide-angle state to a telephoto state, and fT represents an effective focal length of the zoom lens system which is in the telephoto state.

### Claim 2 (depends on 1)

The zoom lens system of claim 1, wherein the zoom lens system satisfies the following condition formula: 1.75<V1/V2<2.45, where V1, V2 are Abbe numbers of the first lens and the second lens in d light, respectively.

### Claim 3 (depends on 1)

The zoom lens system of claim 1, wherein the third lens comprises at least one aspherical surface.

### Claim 4 (depends on 1)

The zoom lens system of claim 1, wherein the sixth lens is a plastic lens.

### Claim 5 (depends on 1)

The zoom lens system of claim 1, wherein the fourth lens and the fifth lens are combined together.

### Claim 6 (depends on 1)

The zoom lens system of claim 1, wherein the third lens group comprises a seventh lens of positive refractive power.

### Claim 7 (depends on 1)

The zoom lens system of claim 1, wherein the zoom lens system satisfies the following condition formula: 0.28<f2/f3<0.5, where f3 represents an effective focal length of the third lens group.

### Claim 8 (depends on 1)

The zoom lens system of claim 1, further comprising an aperture stop positioned between the second lens group and the third lens group.