# US 8,786,964 B2 · Photographing lens assembly

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- Number: US 8,786,964 B2
- Document ID: US8786964B2
- Status: Granted
- Kind: B2
- Application number: 13/647,401
- Filed: 2012-10-09
- Published: 2013-10-24
- Granted: 2014-07-22
- Earliest claimed: 2012-04-20
- Assignees: Largan Precision Co., Ltd.
- Applicants: Largan Precision Co., Ltd.
- Inventors: Tsung-Han Tsai; Wei-Yu Chen
- Web page: https://patentgrep.com/patent/US8786964B2

## CPC

- G02B 13/0035: {having three lenses}
- G02B 9/12: having three components only
- G02B 13/18: with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration {(G02B13/002 takes precedence)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A photographing lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element and a third lens element. The first lens element with positive refractive power has an object-side surface being convex at a paraxial region. The second lens element with negative refractive power has an object-side surface being concave at a paraxial region and an image-side surface being concave or planar at a paraxial region, wherein the second lens element is made of plastic material and the surfaces thereof are aspheric. The third lens element with negative refractive power has an object-side surface being concave at a paraxial region, and an image-side surface being concave at a paraxial region and being convex at a peripheral region, wherein the third lens element is made of plastic material, and the surfaces thereof are aspheric.

## Claims

### Claim 1

A photographing lens assembly comprising, in order from an object side to an image side:
a first lens element with positive refractive power having an object-side surface being convex at a paraxial region;
a second lens element with negative refractive power having an object-side surface being concave at a paraxial region and an image-side surface being concave or planar at a paraxial region, wherein the second lens element is made of plastic material and the object-side surface and the image-side surface of the second lens element are aspheric; and
a third lens element with negative refractive power having an object-side surface being concave at a paraxial region, and an image-side surface being concave at a paraxial region and being convex at a peripheral region, wherein the third lens element is made of plastic material, and the object-side surface and the image-side surface of the third lens element are aspheric;
wherein the photographing lens assembly has a total of three lens elements with refractive power; a distance in parallel with an optical axis from a maximum effective diameter position on the image-side surface of the second lens element to an axial vertex on the image-side surface of the second lens element is SAG22, a central thickness of the second lens element is CT2, and the following relationship is satisfied:
0<SAG22/CT2<0.40.

### Claim 2 (depends on 1)

The photographing lens assembly of claim 1, wherein an Abbe number of the first lens element is V1, an Abbe number of the second lens element is V2, and the following relationship is satisfied:
1.5<V1/V2<3.5.

### Claim 3 (depends on 1)

The photographing lens assembly of claim 1, wherein a focal length of the second lens element is f2, a focal length of the third lens element is f3, and the following relationship is satisfied:
0<f2/f3<1.20.

### Claim 4 (depends on 3)

The photographing lens assembly of claim 3, wherein a curvature radius of the object-side surface of the second lens element is R3, a curvature radius of the image-side surface of the second lens element is R4, and the following relationship is satisfied:
−1.5<R3/R4≦0.

### Claim 5 (depends on 1)

The photographing lens assembly of claim 1, wherein a curvature radius of the object-side surface of the second lens element is R3, a curvature radius of the image-side surface of the second lens element is R4, and the following relationship is satisfied:
−0.35<R3/R4≦0.

### Claim 6

The photographing lens assembly of claim wherein a curvature radius of the object-side surface of the third lens element is R5, a curvature radius of the image-side surface of the third lens element is R6, and the following relationship is satisfied:
−0.35<R6/R5<0.

### Claim 7 (depends on 1)

The photographing fens assembly of claim 1, wherein a focal length of the photographing lens assembly is f, a curvature radius of the image-side surface of the second lens element is R4, a curvature radius of the object-side surface of the third lens element is R5, and the following relationship is satisfied:
0<f/|R4|+f/|R5|<0.80.

### Claim 8 (depends on 1)

The photographing lens assembly of claim 1, wherein a focal length of the photographing lens assembly is f, a curvature radius of the image-side surface of the second lens element is R4, a curvature radius of the object-side surface of the third lens element is R5, and the following relationship is satisfied:
0<f/|R4|+f/|R5|<0.50.

### Claim 9 (depends on 1)

The photographing lens assembly of claim 1, wherein a focal length of the photographing lens assembly is f, a focal length of the first lens element is f1, and the following relationship is satisfied:
1.20<f/f1<2.00.

### Claim 10 (depends on 1)

The photographing lens assembly of claim 1, wherein a focal length of the photographing lens assembly is f, a focal length of the first lens element is f1, and the following relationship is satisfied:
1.40<f/f1<1.80.

### Claim 11 (depends on 1)

The photographing lens assembly of claim 1, wherein a focal length of the photographing lens assembly is f, a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the third lens element is f3, and the following relationship is satisfied:
1.85<(f/f1)−(f/f2)−(f/f3)<3.50.

### Claim 12 (depends on 1)

The photographing lens assembly of claim 1, wherein a central thickness of the second lens element is CT2, a central thickness of the third lens element is CT3, and the following relationship is satisfied:
0.10<CT2/CT3<0.60.

### Claim 13 (depends on 1)

The photographing lens assembly of claim 1, wherein an axial distance between the first lens element and the second lens element is T12, an axial distance between the second lens element and the third lens element is T23, and the following relationship is satisfied:
0.05<T12/T23<0.70.

### Claim 14

A photographing lens assembly comprising, in order from an object side to an image side:
a first lens element with positive refractive power having an object-side surface being convex at a paraxial region;
a second lens element with negative refractive power having an object-side surface being concave at a paraxial region and an image-side surface being concave or planar at a paraxial region, wherein the second lens ent is made of plastic material, and the object-side surface and the image-side surface of the second lens element are aspheric; and
a third lens element with negative refractive power having an object-side surface being concave at a paraxial region, and an image-side surface being concave at a paraxial region and being convex at a peripheral region, wherein the third lens element is made of plastic material, and the object-side surface and the image-side surface of the third lens element are aspheric;
wherein the photographing lens assembly has a total of three lens elements with refractive power; a curvature radius of the object-side surface of the second lens element R3, a curvature radius of the image-side surface of the second lens element is R4, a curvature radius of the object-side surface of the third lens element is R5, a curvature radius of the image-side surface of the third lens element is R6, a focal length of the photographing lens assembly is f, and the following relationships are satisfied:
−1.5<R3/R4≦0;
−0.5<R6/R5<0; and
0<f/|R4|+f/|R5|<0.80.

### Claim 15 (depends on 14)

The photographing lens assembly of claim 14, wherein an Abbe number of the first lens element is V1, an Abbe number of the second lens element is V2, and the following relationship is satisfied:
1.5<V1/V2<3.5.

### Claim 16 (depends on 14)

The photographing lens assembly of claim 14, wherein focal length of the second lens element is f2, a focal length of the third lens element is f3, and the following relationship is satisfied:
0<f2/f3<1.20.

### Claim 17 (depends on 14)

The photographing lens assembly of claim 14, wherein the curvature radius of the object-side surface of the second lens element is R3, the curvature radius of the image-side surface of the second lens element is R4, and the following relationship is satisfied:
−0.35<R3/R4≦0.

### Claim 18 (depends on 14)

The photographing lens assembly of claim 14, wherein the focal length of the photographing lens assembly is f, a focal length of the first lens element is f1, and the following relationship is satisfied:
1.20<f/f1<2.00.

### Claim 19 (depends on 14)

The photographing lens assembly of claim 14, wherein the focal length of the photographing lens assembly is f, a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the third lens element is f3, and the following relationship is satisfied:
1.85<(f/f1)−(f/f2)−(f/f3)<3.50.

### Claim 20 (depends on 14)

The photographing lens assembly of claim 14, wherein a central thickness of the second lens element is CT2, a central thickness of the third lens element is CT 3, and the following relationship is satisfied:
0.10<CT2/CT3<0.60.

### Claim 21 (depends on 14)

The photographing lens assembly of claim 14, wherein an axial distance between the first lens element and the second lens element is T12, an axial distance between the second lens element and the third lens element is T23, and the following relationship is satisfied:
0.05<T12/T23<0.70.

### Claim 22 (depends on 14)

The photographing lens assembly of claim 14, wherein a distance in parallel with an optical axis from a maximum effective diameter position on the image-side surface of the second lens element to an axial vertex on the image-side surface of the second lens element is SAG22, a central thickness of the second lens element is CT2, and the following relationship is satisfied:
0<SAG22/CT2<0.40.