# US 2014/0153109 A1 · Zoom Lens

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- Number: US 2014/0153109 A1
- Document ID: US20140153109A1
- Status: Published application
- Kind: A1
- Application number: 14/091,377
- Filed: 2013-11-27
- Published: 2014-06-05
- Earliest claimed: 2012-12-05
- Assignees: Asia Optical International Ltd.; Sintai Optical (Shenzhen) Co., Ltd.
- Applicants: Asia Optical International Ltd.; Sintai Optical (Shenzhen) Co., Ltd.
- Inventors: Ming-Chung Chen
- Web page: https://patentgrep.com/patent/US20140153109A1

## CPC

- G02B 15/144113: {arranged +-++}
- G02B 15/14: by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A zoom lens includes a first lens group, a second lens group, a third lens group and a fourth lens group, all of which are arranged in sequence from an object side to an image side along an optical axis. The first lens group is with positive refractive power and includes a first lens that is with negative refractive power and a second lens that is with positive refractive power. The second lens group is with negative refractive power. The third lens group is with positive refractive power and includes a third lens front group that is with positive refractive power and a third lens rear group that is with positive refractive power. The fourth lens group is with positive refractive power.

## Claims

### Claim 1

A zoom lens comprising a first lens group, a second lens group, a third lens group and a fourth lens group, all of which are arranged in sequence from an object side to an image side along an optical axis, wherein:
the first lens group is with positive refractive power and comprises a first lens and a second lens, both of which are arranged in sequence from the object side to the image side along the optical axis, wherein the first lens is with negative refractive power and the second lens is with positive refractive power;
the second lens group is with negative refractive power;
the third lens group is with positive refractive power and comprises a third lens front group and a third lens rear group, both of which are arranged in sequence from the object side to the image side along the optical axis, wherein the third lens front group is with positive refractive power and the third lens rear group is with positive refractive power; and
the fourth lens group is with positive refractive power.

### Claim 2 (depends on 1)

The zoom lens as claimed in claim 1, wherein the first lens group, the second lens group, the third lens group and the fourth lens group are movable along the optical axis when the zoom lens zooms.

### Claim 3 (depends on 2)

The zoom lens as claimed in claim 2, wherein an interval between the first lens group and the second lens group increases, an interval between the second lens group and the third lens group decreases and an interval between the third lens group and the fourth lens group varies when the zoom lens zooms from wide-angle end to telephoto end.

### Claim 4 (depends on 1)

The zoom lens as claimed in claim 1, wherein the third lens group satisfies:
0.2<f3/f3a<0.7
0.21<dg3/fw<0.8
wherein f3 is an effective focal length of the third lens group, f3a is an effective focal length of the third lens front group, dg3 is an interval between the third lens front group and the third lens rear group, and fw is an effective focal length of the zoom lens at wide-angle end.

### Claim 5 (depends on 1)

The zoom lens as claimed in claim 1, wherein the second lens group and the third lens group satisfy:
0.32<(β2t/β2w)/(β3t/β3w)<0.7
wherein β2w is a lateral magnification of the second lens group at wide-angle end, β2t is a lateral magnification of the second lens group at telephoto end, β3w is a lateral magnification of the third lens group at wide-angle end, and β3t is a lateral magnification of the third lens group at telephoto end.

### Claim 6 (depends on 1)

The zoom lens as claimed in claim 1, wherein the third lens front group comprises a sixth lens, the sixth lens is with positive refractive power.

### Claim 7 (depends on 6)

The zoom lens as claimed in claim 6, wherein the sixth lens comprises two surfaces, at least one of which is an aspheric surface.

### Claim 8 (depends on 7)

The zoom lens as claimed in claim 7, wherein both of the surfaces are aspheric surfaces.

### Claim 9 (depends on 1)

The zoom lens as claimed in claim 1, wherein the third lens rear group comprises a seventh lens, an eighth lens and a ninth lens, all of which are arranged in sequence from the object side to the image side along the optical axis, wherein the seventh lens is with positive refractive power, the eighth lens is with positive refractive power and the ninth lens is with negative refractive power.

### Claim 10 (depends on 9)

The zoom lens as claimed in claim 9, wherein the seventh lens comprises two surfaces, at least one of which is an aspheric surface.

### Claim 11 (depends on 10)

The zoom lens as claimed in claim 10, wherein both of the surfaces are aspheric surfaces.

### Claim 12 (depends on 9)

The zoom lens as claimed in claim 9, wherein the eighth lens comprises two surfaces, at least one of which is an aspheric surface.

### Claim 13 (depends on 12)

The zoom lens as claimed in claim 12, wherein both of the surfaces are aspheric surfaces.

### Claim 14 (depends on 9)

The zoom lens as claimed in claim 9, wherein the ninth lens comprises two surfaces, at least one of which is an aspheric surface.

### Claim 15 (depends on 14)

The zoom lens as claimed in claim 14, wherein both of the surfaces are aspheric surfaces.

### Claim 16 (depends on 1)

The zoom lens as claimed in claim 1, wherein the fourth lens group comprises a tenth lens, the tenth lens is with positive refractive power.

### Claim 17 (depends on 16)

The zoom lens as claimed in claim 16, wherein the tenth lens is made of plastic material.

### Claim 18 (depends on 17)

The zoom lens as claimed in claim 17, wherein the tenth lens comprises two surfaces, at least one of which is an aspheric surface.

### Claim 19 (depends on 18)

The zoom lens as claimed in claim 18, wherein both of the surfaces are aspheric surfaces.

### Claim 20 (depends on 1)

The zoom lens as claimed in claim 1, further comprising a stop disposed between the second lens group and the third lens group, wherein an interval between the stop and the third lens group is stationary.

### Claim 21 (depends on 1)

The zoom lens as claimed in claim 1, further comprising an optical filter disposed between the fourth lens group and an image plane.