Lens assembly

Patent metadata

Field	Value
Publication number	US-9804360-B2
Application number	US-201514777262-A
Country	US
Kind code	B2
Filing date	Mar 3, 2015
Priority date	Oct 17, 2014
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A lens assembly includes a first lens, a second lens and a third lens from an object side of the lens assembly to an image side of the lens assembly, in turn. The first lens has a positive refractive power and object side with a convexity; the second lens has a negative refractive power; and the third lens has a positive refractive power. The lens assembly has characteristics such as broad filed angle (wide angle), miniaturization and high imaging quality.

First claim

What is claimed is:

1. A lens assembly, comprising:
a first lens, a second lens and a third lens from an object side of the lens assembly to an image side of the lens assembly, in turn, wherein:
the first lens is of a positive refractive power, and an object side of the first lens is of a convexity;
the second lens is of a negative refractive power; and
the third lens is of a positive refractive power, and an image side of the third lens is of a concavity and has one inflection point,
wherein the lens assembly meets the following formulas:
tan(HFOV)>0.74;
TTL/Img H <1.7;
0.6< f 1/ f< 0.8; and
−1.3< f 1/ f 2<−0.8,

wherein HFOV represents a horizontal field of view and equals to half of a field angle of the lens assembly,
TTL represents a total track length of the lens assembly,
ImgH represents half diameter of an effective pixel region of the lens assembly at an imaging plane,
f1 represents a focal length of the first lens,
f2 represents a focal length of the second lens, and
f represents an effective focal length of the lens assembly.

2. The lens assembly according to claim 1 , wherein the lens assembly further meets the following formulas:
|( R 1+ R 2)/( R 1− R 2)|<0.4; and

−1.5< R 2/ f<− 0.5,

wherein R1 represents a curvature radius of the object side of the first lens, and
R2 represents a curvature radius of an image side of the first lens.

3. The lens assembly according to claim 1 , wherein the lens assembly further meets the following formulas:
−8<( R 5+ R 6)/( R 5− R 6)<−4; and

0.8< f 3/ f< 1.6,
wherein R5 represents a curvature radius of an object side of the third lens,
R6 represents a curvature radius of the image side of the third lens, and
f3 represents a focal length of the third lens.

4. The lens assembly according to claim 1 , wherein the lens assembly further meets the following formulas:
1.4< CT 1/ CT 2<1.9; and
1.8< CT 3/ CT 2<2.0,
wherein CT1 represents a center thickness of the first lens, CT2 represents a center thickness of the second lens, and CT3 represents a center thickness of the third lens.

5. The lens assembly according to claim 1 , wherein the lens assembly further meets the following formula:
0.4<( CT 1+ CT 2+ CT 3)/TTL<0.6.

6. The lens assembly according to claim 1 , wherein
an image side of the first lens is of a convexity,
an object side of the second lens is of a concavity,
an image side of the second lens is of a convexity, and
an object side of the third lens is of a convexity and has one inflection point.

7. The lens assembly according to claim 1 , further comprising a diaphragm arranged between an object being imaged and the second lens.

8. The lens assembly according to claim 1 , wherein each of the first lens, the second lens and the third lens is made of a plastic material.

9. The lens assembly according to claim 1 , wherein an image side of the second lens has one inflection point.

Assignees

• Zhejiang Sunny Optics Co Ltd

Inventors

• Huang Lin
• Dai Fujian

Classifications

• G02B27/0025

  for optical correction, e.g. distorsion, aberration · CPC title

• G02B13/0035 Primary

  having three lenses · CPC title

• G02B9/16

  all the components being simple · CPC title