# US 12,222,477 B2 · Zoom optical system

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- Number: US 12,222,477 B2
- Document ID: US12222477B2
- Status: Granted
- Kind: B2
- Application number: 18/599,409
- Filed: 2024-03-08
- Published: 2024-06-27
- Granted: 2025-02-11
- Earliest claimed: 2016-01-26
- Assignees: Samsung Electro-Mechanics Co., Ltd.
- Applicants: Samsung Electro-Mechanics Co., Ltd.
- Inventors: Tae Youn Lee; Jung Hui Ko
- Web page: https://patentgrep.com/patent/US12222477B2

## CPC

- 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 13/009: {having zoom function}
- G02B 15/143507: {arranged -++}
- G02B 5/005: {Diaphragms (for cameras G03B9/02)}
- G02B 5/208: {for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation}
- G02B 13/02: Telephoto objectives, i.e. systems of the type + - in which the distance from the front vertex to the image plane is less than the equivalent focal length
- G02B 27/0025: {for optical correction, e.g. distorsion, aberration}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A zoom optical system includes a first lens group, a position of which with respect to an imaging plane is adjustable, and including first and second lenses. The zoom optical system also includes a second lens group of which a position with respect to the imaging plane is adjustable and includes third to fifth lenses. The zoom optical system further includes a third lens group including a sixth lens. An object-side surface of the first lens is convex.

## Claims

### Claim 1

A zoom optical system, comprising:
a first lens group comprising a negative refractive power;
a second lens group comprising a positive refractive power; and
a third lens group comprising a positive refractive power,
wherein
the first to third lens groups are sequentially disposed from an object side toward an imaging plane,
upon zooming from a wide-angle position to a telephoto position, a gap between the first and second lens groups is decreased,
a gap between the second and third lens groups is adjustable,
the first lens group comprises a first lens and a second lens, the second lens group comprises a third lens, a fourth lens having a convex object-side surface, and a fifth lens having a convex object-side surface, and the third group comprises a sixth lens, and
1.9≤|fG1/fw|≤3.0, 4.0<ft/fw<7.0, and 1.61<n4<1.68, where fw is an overall focal length of the zoom optical system in the wide-angle position, fG1 is a synthesized focal length of the first lens group, ft is an overall focal length of the zoom optical system in the telephoto position, and n4 is a refractive index of the fourth lens.

### Claim 2 (depends on 1)

The zoom optical system of claim 1, wherein
the first lens comprises a negative refractive power and is made of plastic, and one surface thereof is aspherical, and
the second lens comprises a positive refractive power, and made of plastic.

### Claim 3 (depends on 1)

The zoom optical system of claim 1, wherein the third lens comprises a positive refractive power, is made of plastic, and an object-side surface there of is convex;
the fourth lens is made of plastic, and
the fifth lens is made of plastic.

### Claim 4 (depends on 1)

The zoom optical system of claim 1, wherein the sixth lens comprises a positive refractive power and is made of plastic.

### Claim 5 (depends on 1)

The zoom optical system of claim 1, further comprising a stop disposed between the first and second lens groups.

### Claim 6 (depends on 1)

The zoom optical system of claim 1, wherein an image-side surface of the first lens is concave and an object-side surface of the first lens is one of convex and concave.

### Claim 7 (depends on 1)

The zoom optical system of claim 1, wherein the first to sixth lenses have an aspherical shape.

### Claim 8 (depends on 1)

The zoom optical system of claim 1, wherein 1.51<n3<1.57, where n3 is a refractive index of the third lens.

### Claim 9 (depends on 1)

The zoom optical system of claim 1, wherein 0.7<|fG2/fG1|<1.2, where fG1 is the synthesized focal length of the first lens group, and fG2 is a synthesized focal length of the second lens group.

### Claim 10 (depends on 1)

The zoom optical system of claim 1, wherein 1.4<fG2/fw<2.8, w here fG2 is a synthesized focal length of the second lens group, and fw is the overall focal length of the zoom optical system in the wide-angle position.

### Claim 11 (depends on 1)

The zoom optical system of claim 1, wherein TG1+TG2+TG3<8.5, where TG1 is a distance from an object-side surface of the first lens to an image-side surface of the second lens, TG2 is a distance from an object-side surface of the third lens to an image-side surface of the fifth lens, TG3 is a thickness of the sixth lens at a center of an optical axis.

### Claim 12 (depends on 1)

The zoom optical system of claim 1, wherein 0.25<1−MG3T2<0.6, where MG3T is an imaging magnification of the third lens group positioned in the telephoto position at infinity.

### Claim 13 (depends on 1)

The zoom optical system of claim 1, wherein 4.0<MG2T/MG2W<6.8, where MG2T is an imaging magnification of the second lens group positioned in the telephoto position at infinity, and MG2W is an imaging magnification of the second lens group positioned in the wide-angle position at infinity.

### Claim 14 (depends on 1)

The zoom optical system of claim 1, wherein 50<V1<60, where V1 is an Abbe number of the first lens.

### Claim 15 (depends on 1)

The zoom optical system of claim 1, wherein 30<V1−V2<37, where V1 is an Abbe number of the first lens and V2 is an Abbe number of the second lens.

### Claim 16 (depends on 1)

The zoom optical system of claim 1, wherein n1+n2<3.25, where n1 is a refractive index of the first lens and n2 is a refractive index of the second lens.

### Claim 17 (depends on 1)

The zoom optical system of claim 1, wherein 0<n4−n1<0.2, where n1 is a refractive index of the first lens and n4 is the refractive index of the fourth lens.

### Claim 18 (depends on 1)

The zoom optical system of claim 1, wherein 2.2<fw/EPDw<3.0, where fw is the overall focal length of the zoom optical system in the wide-angle position and EPDw is an entrance pupil diameter in the wide-angle position.