Optical lens system, imaging device and electronic device

Patent metadata

Field	Value
Publication number	US-2016274331-A1
Application number	US-201615168224-A
Country	US
Kind code	A1
Filing date	May 30, 2016
Priority date	Apr 8, 2014
Publication date	Sep 22, 2016
Grant date	—

Abstract

An optical lens system comprises, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, and a fourth lens element. The first lens element with positive refractive power has an object-side surface being convex in a paraxial region. The second lens element with refractive power has an image-side surface being convex in a paraxial region. The third lens element with positive refractive power has an aspheric object-side surface being concave in a paraxial region and an aspheric image-side surface being convex in a paraxial region. The fourth lens element with refractive power has an aspheric object-side surface being concave in a paraxial region and an aspheric image-side surface being convex in a paraxial region. There are a total of four lens elements with refractive power in the optical lens system.

First claim

What is claimed is:

1 . An optical lens system 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, and an image-side surface being concave in a paraxial region thereof; a second lens element having negative refractive power; a third lens element having an object-side surface being concave in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof, both of the object-side surface and the image-side surface of the third lens element being aspheric; and a fourth lens element having an object-side surface being concave in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof, both of the object-side surface and the image-side surface of the fourth lens element being aspheric; wherein the optical lens system has a total of four non-cemented lens elements, 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 conditions are satisfied:
| f 1/ f 2|+| f 1/ f 3|+| f 1/ f 4|<1.80.

2 . The optical lens system of claim 1 , wherein the focal length of the first lens element is f1, the focal length of the second lens element is f2, the focal length of the third lens element is f3, the focal length of the fourth lens element is f4, and the following conditions are satisfied:
0.50<| f 1/ f 2|+| f 1/ f 3|+| f 1/ f 4|<1.50.

3 . The optical lens system of claim 2 , wherein the focal length of the first lens element is f1, the focal length of the second lens element is f2, the focal length of the third lens element is f3, the focal length of the fourth lens element is f4, and the following conditions are satisfied:
0.50<| f 1/ f 2|+| f 1/ f 3|+| f 1/ f 4|≦1.25.

4 . The optical lens system of claim 1 , wherein the first lens element has the largest central thickness among each of central thicknesses of the first lens element, the second lens element, the third lens element, and the fourth lens element.

5 . The optical lens system of claim 1 , wherein both of the object-side surface and the image-side surface of the first lens element are aspheric, both of an object-side surface and an image-side surface of the second lens element are aspheric; the first lens element, the second lens element, the third lens element and the fourth lens element are made of plastic, and an absolute value of the focal length of the first lens element is the smallest among each of absolute values of the focal lengths of the first lens element, the second lens element, the third lens element, and the fourth lens element.

6 . The optical lens system of claim 1 , wherein 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 condition is satisfied:
T 23/ T 34<5.0.

7 . The optical lens system of claim 1 , wherein the second lens element has an object-side surface being concave in a paraxial region thereof.

8 . The optical lens system of claim 1 , wherein the focal length of the third lens element and the focal length of the fourth lens element are opposite in signs.

9 . The optical lens system of claim 1 , wherein an incident angle between a chief ray and a normal line on an image plane at a maximum image height is CRA, and the following condition is satisfied:
CRA< 27.5 degrees.

10 . The optical lens system of claim 1 , wherein a curvature radius of an 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 condition is satisfied:
R 4/ R 3<2.0.

11 . The optical lens system of claim 1 , 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 conditions are satisfied:
0< R 5/ R 6<20.

12 . The optical lens system of claim 1 , wherein the fourth lens element has negative refractive power, and at least one of the object-side surface and the image-side surface of the fourth lens element has at least one inflection point.

13 . The optical lens system of claim 1 , wherein at least one of an object-side surface and an image-side surface of the second lens element has at least one inflection point.

14 . An optical lens system 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 having negative refractive power; a third lens element having an object-side surface being concave in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof, both of the object-side surface and the image-side surface of the third lens element being aspheric; and a fourth lens element having an object-side surface being concave in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof, both of the object-side surface and the image-side surface of the fourth lens element being aspheric; wherein the optical lens system has a total of four non-cemented lens elements, Abbe numbers of at least two of the first, second, third and fourth lens elements are smaller than 32, 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 conditions are satisfied:
| f 1/ f 2|+| f 1/ f 3|+| f 1/ f 4|<1.50.

15 . The optical lens system of claim 14 , wherein the first lens element has the largest central thickness among central thicknesses of the first lens element, the second lens element, the third lens element, and the fourth lens element.

16 . The optical lens system of claim 14 , wherein both of the object-side surface and the image-side surface of the first lens element are aspheric, both of an object-side surface and an image-side surface of the second lens element are aspheric; the first lens element, the second lens element, the third lens element and the fourth lens element are made of plastic, and an absolute value of the focal length of the first lens element is the smallest among each of absolute values of the focal lengths of the first lens element, the second lens element, the third lens element, and the fourth lens element.

17 . The optical lens system of claim 14 , wherein 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 condition is satisfied:
T 23/ T 34<5.0.

18 . The optical lens system of claim 14 , wherein the focal length of the third lens element and the focal length of the fourth lens element are opposite in signs.

19 . The optical lens system of claim 14 , wherein an incident angle between a chief ray and a normal line on an image plane at a maximum image height is CRA, and the following condition is satisfied:
CRA< 27.5 degrees.

20 . The optical lens system of claim 14 , wherein a curvature radius of an object-side surface of the second lens element is R3, a curvature radius of t

Assignees

• Largan Precision Co Ltd

Inventors

• Hsueh Chun-Che
• Chen Wei-Yu

Classifications

• H04N23/54

  Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils · CPC title

• G02B9/34

  having four components only · CPC title

• G02B13/18

  with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration {(G02B13/002 takes precedence)} · CPC title

• G02B13/004 Primary

  having four lenses · CPC title

• G02B13/008

  designed for infrared light · CPC title