# US 8,786,962 B2 · Photographing system

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- Number: US 8,786,962 B2
- Document ID: US8786962B2
- Status: Granted
- Kind: B2
- Application number: 13/593,490
- Filed: 2012-08-23
- Published: 2013-05-09
- Granted: 2014-07-22
- Earliest claimed: 2011-11-07
- Assignees: Largan Precision Co., Ltd.
- Applicants: Chun-Shan Chen; Hsiang-Chi Tang; Po-Lun Hsu; Ming-Ta Chou
- Inventors: Chun-Shan Chen; Hsiang-Chi Tang; Po-Lun Hsu; Ming-Ta Chou
- Web page: https://patentgrep.com/patent/US8786962B2

## CPC

- G02B 3/04: with continuous faces that are rotationally symmetrical but deviate from a true sphere {, e.g. so called "aspheric" lenses}
- G02B 13/0045: {having five or more lenses}
- G02B 9/60: having five 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 system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element. The first lens element with positive refractive power has a convex object-side surface. The second lens element has negative refractive power. The third lens element with positive refractive power is made of plastic material and has a convex object-side surface and a convex image-side surface. The fourth lens element with negative refractive power is made of plastic material and has a concave object-side surface and a convex image-side surface. The fifth lens element with refractive power is made of plastic material and has a concave image-side surface, wherein the fifth lens element has at least one inflection point. The object-side surfaces and the image-side surfaces of the third through fifth lens elements are aspheric.

## Claims

### Claim 1

A photographing system comprising, in order from an object side to an image side:
a first lens element with positive refractive power having a convex object-side surface;
a second lens element with negative refractive power;
a third lens element with positive refractive power made of plastic material and having a convex object-side surface and a convex image-side surface, wherein the object-side surface and the image-side surface of the third lens element are aspheric;
a fourth lens element with negative refractive power made of plastic material and having a concave object-side surface and a convex image-side surface, wherein the object-side surface and the image-side surface of the fourth lens element are aspheric; and
a fifth lens element with refractive power made of plastic material and having a concave image-side surface, wherein an object-side surface and the image-side surface of the fifth lens element are aspheric, and the fifth lens element has at least one inflection point formed on at least one of the object-side surface and the image-side surface thereof;
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, an axial distance between the object-side surface of the first lens element and the image-side surface of the fifth lens element is Td, and a central thickness of the fifth lens element is CT5, the following relationships are satisfied:
−4.5<R5/R6<−1.0; and
2.0<Td/CT5<4.4.

### Claim 2 (depends on 1)

The photographing system of claim 1, wherein the fifth lens element has a convex object-side surface.

### Claim 3 (depends on 1)

The photographing system of claim 1, wherein a curvature radius of the object-side surface of the fourth lens element is R7, and a focal length of the photographing system is f, the following relationship is satisfied:
−0.5<R7/f<0.

### Claim 4 (depends on 2)

The photographing system of claim 2, wherein a central thickness of the fourth lens element is CT4, and the central thickness of the fifth lens element is CT5, the following relationship is satisfied:
2.4<CT5/CT4<4.5.

### Claim 5 (depends on 2)

The photographing system of claim 2, wherein an Abbe number of the third lens element is V3, and an Abbe number of the fourth lens element is V4, the following relationship is satisfied:
30<V3−V4<45.

### Claim 6 (depends on 2)

The photographing system of claim 2, wherein a focal length of the photographing system is f, a focal length of the third lens element is f3, a focal length of the fourth lens element is f4, and a focal length of the fifth lens element is f5, the following relationship is satisfied:
0.5<f/f3+|f/f4|<|f/f5|<1.6.

### Claim 7

The photographing system of wherein a curvature radius of the object-side surface of the first lens element is R1 and a curvature radius of an image-side surface of the first lens element is R2, the following relationship is satisfied:
−3.0<(R1+R2)/(R1−R2)<−0.7.

### Claim 8 (depends on 3)

The photographing system of claim 3, wherein the curvature radius of the object-side surface of the third lens element is R5, and the curvature radius of the image-side surface of the third lens element is R6, the following relationship is satisfied:
−3.5<R5/R6<−1.3.

### Claim 9 (depends on 2)

The photographing system of claim 2, wherein an axial distance between the object-side surface of the first lens element d an image plane is TTL, and a maximum image height of the photographing system is ImgH, the following relationship is satisfied:
TTL/ImgH<1.80.

### Claim 10

A photographing system comprising, in order from an object side to an image side:
a first lens element with positive refractive power having a convex object-side surface;
a second lens element with negative refractive power;
a third lens element with positive refractive power made of plastic material and having a convex object-side surface and a convex image-side surface, wherein the object-side surface and the image-side surface of the third lens element are aspheric;
a fourth lens element with negative refractive power made of plastic material and having a concave object-side surface and a convex image-side surface, wherein the object-side surface and the image-side surface of the fourth lens element are aspheric; and
a fifth lens element with refractive power made of plastic material having a concave image-side surface, wherein an object-side surface and the image-side surface of the fifth lens element are aspheric, and the fifth lens element has at least one inflection point formed on at least one of the object-side surface and the mage-side surface thereof;
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, an Abbe number of the third lens element is V3, and an Abbe number of the fourth lens element is V4, the following relationships are satisfied:
−5.5<R5/R6<0.0; and
30<V3−V4<45.

### Claim 11 (depends on 10)

The photographing system of claim 10, wherein the fifth lens element has a convex object-side surface.

### Claim 12 (depends on 10)

The photographing system of claim 10, wherein a curvature radius of the object-side surface of the fourth lens element is R7, and a fecal length of the photographing system is f, the following relationship is satisfied:
−0.5<R7/f<0.

### Claim 13 (depends on 10)

The photographing system of claim 10, wherein a central thickness of the fourth lens element is CT4, and a central thickness of the fifth lens element is CT5, the following relationship is satisfied:
2.4<CT5/CT4<4.5.

### Claim 14 (depends on 10)

The photographing system of claim 10, wherein a focal length of the photographing system is f, a focal length of the third lens element is f3, a focal length of the fourth lens element is f4, and a focal length of the fifth lens element is f5, the following relationship is satisfied:
0.5<f/f3±|f/f4|+|f/f5|<1.6.

### Claim 15 (depends on 10)

The photographing system of claim 10, wherein the curvature radius of the object-side surface of the third lens element is R5, and the curvature radius of the image-side surface of the third lens element is R6, the following relationship is satisfied:
−4.5<R5/R6<−1.0.

### Claim 16 (depends on 15)

The photographing system of claim 15, wherein the curvature radius of the object-side surface of the third lens element is R5, and the curvature radius of the image-side surface of the third lens element is R6, the following relationship is satisfied:
−3.5<R5/R6<−1.3.

### Claim 17 (depends on 10)

The photographing system of claim 10, wherein an axial distance between the object-side surface of the first lens element d an image plane is TTL, and a maximum image height of the photographing system is ImgH, the following relationship is satisfied:
TTL/ImgH<1.80.