# US 8,570,667 B2 · Optical lens assembly for image capture

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- Number: US 8,570,667 B2
- Document ID: US8570667B2
- Status: Granted
- Kind: B2
- Application number: 13/189,243
- Filed: 2011-07-22
- Published: 2012-09-27
- Granted: 2013-10-29
- Earliest claimed: 2011-03-21
- Assignees: Largan Precision Co., Ltd.
- Applicants: Po-Lun Hsu; Ming-Ta Chou; Tsung-Han Tsai
- Inventors: Po-Lun Hsu; Ming-Ta Chou; Tsung-Han Tsai
- Web page: https://patentgrep.com/patent/US8570667B2

## CPC

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

## Abstract

An optical lens assembly for image capture, in order from an object side to an image side, comprising: a first lens element with positive refractive power having a concave object-side surface and a convex image-side surface, a second lens element with negative refractive power having a concave object-side surfaces and a convex image-side surface, a third lens element with positive refractive power having bi-convex surface. Additionally, the optical lens assembly for image capture satisfies several desirable conditions. By such arrangements, the optical assembly for image capture can effectively correct the aberration and be used as a compact image pickup device for image taking.

## Claims

### Claim 1

An optical lens assembly for image capture, sequentially arranged from an object side to an image side with no intervening lenses, comprising:
a first lens element with positive refractive power, having a concave object-side surface in proximity to an optical axis and a convex image-side surface in proximity to the optical axis;
a second lens element with negative refractive power, having a concave object-side surface in proximity to the optical axis and a convex image-side surface in proximity to the optical axis; and
a third lens element with positive refractive power, having a convex object-side surface in proximity to the optical axis and a convex image-side surface in proximity to the optical axis,
wherein the optical lens assembly for image capture has a total of three lens elements with refractive power;
wherein f is a focal length of the optical lens assembly for image capture, f1 is a focal length of the first lens element, and the condition of 1.0<f/f1<1.9 is satisfied; and
wherein R5 is a curvature radius of the object-side surface of the third lens element, R6 is a curvature radius of the ima e-side surface of the third lens element, and the condition of −0.7<R5/R6<0 is satisfied.

### Claim 2 (depends on 1)

The optical lens assembly for image capture of claim 1, wherein the second lens element and the third lens element are made of plastic; each of the second lens element and the third lens element has an object-side surface and an image-side surface, at least one of the object-side surface and the image-side surface of both the second lens element and the third lens element being aspheric; the third lens element has at least one inflection point.

### Claim 3 (depends on 2)

The optical lens assembly for image capture of claim 2, further comprising a stop; wherein SL is an axial distance between the stop and an image plane, TTL is an axial distance from the object-side surface of the first lens element to the image plane, and the condition of 0.90<SL/TTL<1.20 is satisfied.

### Claim 4 (depends on 3)

The optical lens assembly for image capture of claim 3, wherein f is a focal length of the optical lens assembly for image capture, f1 is a focal length of the first lens element, and the condition of 1.2<f/f1<1.6 is satisfied.

### Claim 5 (depends on 3)

The optical lens assembly for image capture of claim 3, wherein R3 is a curvature radius of the object-side surface of the second lens element, R4 is a curvature radius of the image-side surface of the second lens element, and the condition of 0.3<|R3/R4|<0.8 is satisfied.

### Claim 6 (depends on 3)

The optical lens assembly for image capture of claim 3, wherein v1 is an Abbe number of the first lens element, v2 is an Abbe number of the second lens element, and the condition of 24<v1−v2<40 is satisfied.

### Claim 7 (depends on 3)

The optical lens assembly for image capture of claim 3, wherein f2 is a focal length of the second lens element, f3 is a focal length of the third lens element, and the condition of 0.6<|f2|/f3<0.9 is satisfied.

### Claim 8 (depends on 2)

The optical lens assembly for image capture of claim 2, wherein CT2 is a central thickness of the second lens element, f is a focal length of the optical lens assembly for image capture, and the condition of 0.03<CT2/f<0.13 is satisfied.