# US 9,753,254 B2 · Imaging lens assembly, image capturing device, and electronic device

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- Number: US 9,753,254 B2
- Document ID: US9753254B2
- Status: Granted
- Kind: B2
- Application number: 14/812,304
- Filed: 2015-07-29
- Published: 2016-10-06
- Granted: 2017-09-05
- Earliest claimed: 2015-03-31
- Assignees: Largan Precision Co., Ltd.
- Applicants: Largan Precision Co., Ltd.
- Inventors: Hsin-Hsuan Huang
- Web page: https://patentgrep.com/patent/US9753254B2

## CPC

- G02B 13/004: {having four lenses}
- G02B 9/34: having four components only
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An imaging lens assembly includes, in order from an object side to an image side, a first lens element (100), a second lens element (120), a third lens element (130), and a fourth lens element (140). The first lens element (110) with positive refractive power has an object-side surface (111) being convex. The second lens element (120) with negative refractive power has an object-side surface (121) being concave. The third lens element (130) with positive refractive power has an object-side surface (131) and an image-side surface (132) being both aspheric. The fourth lens element (140) with refractive power has an object-side surface (141) and an image-side surface (142) being aspheric.

## Claims

### Claim 1

An imaging 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 in a paraxial region thereof;
a second lens element with negative refractive power having an object-side surface being concave in a paraxial region thereof;
a third lens element with positive refractive power having an object-side surface and an image-side surface being aspheric; and
a fourth lens element with negative refractive power having an object-side surface and an image-side surface being aspheric;
wherein the imaging lens assembly further comprises an aperture stop, wherein no lens element is disposed between the aperture stop and the first lens element; the imaging lens assembly has a total of four lens elements, there is an air gap between every two of the first lens element, the second lens element, the third lens element, and the fourth lens element that are adjacent to each other, a curvature radius of the object-side surface of the second lens element is R3, a curvature radius of an image-side surface of the second lens element is R4, a focal length of the imaging lens assembly is f, a maximum image height of the imaging lens assembly is ImgH, 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, a central thickness of the second lens element is CT2, an axial distance between the object-side surface of the first lens element and an image surface is TL, and the following conditions are satisfied:
(R3+R4)/(R3−R4)<0;
2.4<f/ImgH<6.5;
−4.0<R3/T23<0;
0.3<T12/CT2<5.0; and
0.95<f/TL<1.5.

### Claim 2 (depends on 1)

The imaging lens assembly of claim 1, wherein the image-side surface of the third lens element being convex in a paraxial region thereof.

### Claim 3 (depends on 1)

The imaging lens assembly of claim 1, wherein the fourth lens element has the image-side surface being concave in a paraxial region thereof and at least one convex shape on the image-side surface in an off-axis region thereof.

### Claim 4 (depends on 1)

The imaging lens assembly of claim 1, wherein the third lens element has the object-side surface being convex in a paraxial region thereof.

### Claim 5 (depends on 1)

The imaging lens assembly of claim 1, wherein the fourth lens element has the object-side surface being concave in a paraxial region thereof.

### Claim 6 (depends on 1)

The imaging lens assembly of claim 1, wherein the second lens element has the image-side surface being convex in a paraxial region thereof.

### Claim 7 (depends on 1)

The imaging lens assembly of claim 1, 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 a maximum refractive index among the first lens element, the second lens element, the third lens element and the fourth lens element is Nmax, the following conditions are satisfied:
|R3|<|R4|; and
1.50<Nmax<1.70.

### Claim 8 (depends on 1)

The imaging lens assembly of claim 1, wherein the focal length of the imaging lens assembly is f, a curvature radius of the object-side surface of the first lens element is R1, and the following condition is satisfied:
3.3<f/R1<8.5.

### Claim 9 (depends on 1)

The imaging lens assembly of claim 1, wherein the focal length of the imaging lens assembly is f, and the following condition is satisfied:
5.5 mm<f<12.0 mm.

### Claim 10 (depends on 1)

The imaging lens assembly of claim 1, wherein the axial distance between the first lens element and the second lens element is T12, and the central thickness of the second lens element is CT2, and the following condition is satisfied:
0.4<T12/CT2<3.0.

### Claim 11 (depends on 1)

The imaging lens assembly of claim 1, wherein the focal length of the imaging 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, a focal length of the fourth lens element is f4, and the following condition is satisfied:
5.0<|f/f1|+|f/f2|+|f/f3|+|f/f4|.

### Claim 12 (depends on 1)

The imaging lens assembly of claim 1, wherein the second lens element has at least one convex shape on the object-side surface in an off-axis region thereof, a sum of central thicknesses of the first lens element, the second lens element, the third lens element, and the fourth lens element is ΣCT, an axial distance between the object-side surface of the first lens element and the image-side surface of the fourth lens element is TD, and the following condition is satisfied:
ΣCT/TD<0.55.

### Claim 13 (depends on 1)

The imaging lens element of claim 1, wherein at least one inflection point is positioned on at least one surface of the second lens element, the third lens element, or the fourth lens element, an axial distance between the aperture stop and the image-side surface of the fourth lens element is SD, an axial distance between the object-side surface of the first lens element and the image-side surface of the fourth lens element is TD, and the following condition is satisfied:
0.65<SD/TD<1.0.

### Claim 14 (depends on 1)

The imaging lens assembly of claim 1, wherein an entrance pupil diameter of the imaging lens assembly is EPD, a maximum image height of the imaging lens assembly is ImgH, and the following condition is satisfied;
0.9<EPD/ImgH<2.0.

### Claim 15

An imaging 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 in a paraxial region thereof;
a second lens element with negative refractive power having an object-side surface being concave in a paraxial region thereof;
a third lens element with positive refractive power having an object-side surface and an image-side surface being aspheric; and
a fourth lens element with negative refractive power having an object-side surface and an imaging-side surface being aspheric;
wherein the imaging lens assembly further comprises an aperture stop, wherein no lens element is disposed between the aperture stop and the first lens element; the imaging lens assembly has a total of four lens elements, there is an air gap between every two of the first lens element, the second lens element, the third lens element, and the fourth lens element that are adjacent to each other, a curvature radius of the object-side surface of the first lens element is R1, a curvature radius of an image-side surface of the first lens element is R2, a curvature radius of the object-side surface of the second lens element is R3, a curvature radius of an image-side surface of the second lens element is R4, a focal length of the imaging lens assembly is f, a maximum image height of the imaging lens assembly is ImgH, a central thickness of the first lens element is CT1, and the following conditions are satisfied:
(R3+R4)/(R3−R4)<0;
2.4<f/ImgH<6.5;
−0.50<R1/R2<0.50; and
3.0<(f/R1)−(f/R2)+((f*CT1)/(R1*R2))<7.5.

### Claim 16 (depends on 15)

The imaging lens assembly of claim 15, wherein the third lens element has the object-side surface being concave in a paraxial region thereof.

### Claim 17 (depends on 15)

The imaging lens element of claim 15, wherein the fourth lens element has the object-side surface being convex in a paraxial region thereof and the image-side surface being concave in a paraxial region thereof, and at least one convex shape on the image-side surface in an off-axis region thereof.

### Claim 18 (depends on 15)

The imaging lens element of claim 15, wherein a half of maximum field of view of the imaging lens assembly is HFOV, and the following condition is satisfied:
0.20<tan(2*HFOV)<0.90.

### Claim 19 (depends on 15)

The imaging lens assembly of claim 15, wherein the first lens element, the second lens element, the third lens element, and the fourth lens element are made of plastic material, an Abbe number of the second lens element is V2, an Abbe number of the third lens element is V3, and the following condition is satisfied:
20<V2+V3<60.

### Claim 20 (depends on 15)

The imaging lens assembly of claim 15, 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 an axial distance between the object-side surface of the first lens element and an image surface is TL, and the following conditions are satisfied:
|R3|<|R4|; and
TL<10.0 mm.

### Claim 21 (depends on 15)

The imaging lens assembly of claim 15, wherein the focal length of the imaging lens assembly is f, and the maximum image height of the imaging lens assembly is ImgH, and the following condition is satisfied:
2.7<f/ImgH<5.0.

### Claim 22 (depends on 15)

The imaging lens assembly of claim 15, wherein the curvature radius of the object-side surface of the first lens element is R1, the curvature radius of the image-side surface of the first lens element is R2, 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, an axial distance between the third lens element and the fourth lens element is T34, and the following conditions are satisfied:
−0.30<R1/R2<0.30; and
0<T12/(T23+T34)<0.60.

### Claim 23 (depends on 15)

The imaging lens assembly of claim 15, wherein the focal length of the imaging lens assembly is f, the curvature radius of the object-side surface of the first lens element is R1, the central thickness of the first lens element is CT1, a central thickness of the second lens element is CT2, and the following conditions are satisfied:
3.3<f/R1<8.5; and
1.7<CT1/CT2<8.0.

### Claim 24 (depends on 15)

The imaging lens assembly of claim 15, wherein at least one inflection point is positioned on at least one surface of the third lens element or the fourth lens element, an axial distance between the object-side surface of the first lens element and an image surface is TL, a maximum image height of the imaging lens assembly is ImgH, and the following condition is satisfied:
2.5<TL/ImgH<4.0.

### Claim 25 (depends on 15)

The imaging lens assembly of claim 15, wherein the object-side surface of the second lens element has at least one convex shape in an off-axis region thereof, an effective radius of the object-side surface of the first lens element is Y11, and an effective radius of the image-side surface of the fourth lens element is Y42, and the following condition is satisfied:
0.7<Y11/Y42<1.8.

### Claim 26 (depends on 15)

The imaging lens assembly of claim 15, wherein a largest distance between every two adjacent lens elements among all the lens elements is a distance between the second lens element and the third lens element, an axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, a central thickness of the third lens element is CT3, and the following condition is satisfied:
2.50<(T23+T34)/CT3.

### Claim 27 (depends on 15)

The imaging lens assembly of claim 15, wherein a largest distance between every two adjacent lens elements among all the lens elements is a distance between the third lens element and the fourth lens element.

### Claim 28 (depends on 15)

An image capturing device comprising:
the imaging lens assembly of claim 15; and
an image sensor.

### Claim 29 (depends on 28)

An electronic device comprising:
the image capturing device of claim 28.