Imaging lens system, image capturing device and electronic device

Patent metadata

Field	Value
Publication number	US-9482844-B2
Application number	US-201414564589-A
Country	US
Kind code	B2
Filing date	Dec 9, 2014
Priority date	Oct 20, 2014
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

An imaging lens 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 with negative refractive power has a convex object-side surface and a concave image-side surface. The third lens element with negative refractive power has a concave image-side surface and the image-side surface having at least one inflection point in an off-axis region. The fourth lens element with positive refractive power has a concave object-side surface and a convex image-side surface. The fifth lens element with negative refractive power has a concave object-side surface and a concave image-side surface with at least one convex shape in an off-axis region.

First claim

What is claimed is:

1. An imaging 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 with negative 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 third lens element with negative refractive power having an image-side surface being concave in a paraxial region thereof, an object-side surface and the image-side surface thereof being aspheric, the image-side surface having at least one inflection point in an off-axis region thereof;
a fourth lens element with positive refractive power having an object-side surface being concave in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof, the object-side surface and the image-side surface thereof being aspheric; and
a fifth lens element with negative refractive power having an object-side surface being concave in a paraxial region thereof and an image-side surface being concave in a paraxial region thereof, the object-side surface and the image-side surface thereof being aspheric, the image-side surface having at least one convex shape in an off-axis region thereof; wherein the imaging lens system has a total of five lens element with refractive power and an air gap is arranged between every two adjacent lens elements with refractive power;
wherein an Abbe number of the second lens element is V2, an Abbe number of the third lens element is V3, a curvature radius of the object-side surface of the second lens element is R3, a focal length of the imaging lens system is f, an axial distance between the third lens element and the fourth lens element is T34, an axial distance between the fourth lens element and the fifth lens element is T45, a central thickness of the fourth lens element is CT4, and the following conditions are satisfied:
| V 2− V 3|<10;

| R 3|/ f< 4.0; and
1.15<( T 34+ T 45)/ CT 4<2.0.

2. The imaging lens system of claim 1 , wherein the first lens element has an image-side surface being concave in a paraxial region thereof.

3. The imaging lens system of claim 2 , wherein the image-side surface of the fourth lens element has at least one critical point.

4. The imaging lens system of claim 2 , wherein a focal length of the first lens element is f1, a focal length of the fourth lens element is f4, and the following condition is satisfied:
|( f 1− f 4)/( f 1+ f 4)|<0.15.

5. The imaging lens system of claim 2 , wherein the focal length of the imaging lens system is f, 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, a curvature radius of the object-side surface of the fourth lens element is R7, and the following condition is satisfied:
f/|R 5|+ f/|R 6|+ f/|R 7|<1.50.

6. The imaging lens system of claim 5 , wherein a focal length of the third lens element is f3, an axial distance between the first lens element and the second lens element is T12, and the following condition is satisfied:
f 3/ T 12<−1000.

7. The imaging lens system of claim 5 , wherein the third lens element has negative refractive power at a peripheral region thereof.

8. The imaging lens system of claim 1 further comprising a stop, wherein an axial distance between the stop and the image-side surface of the fifth lens element is Sd, 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, the focal length of the imaging lens system is f, and the following condition is satisfied:
0.87< Sd/Td< 0.98; and
2.8 mm< f< 4.2 mm.

9. The imaging lens system of claim 8 , wherein the fifth lens element has positive refractive power at a peripheral region thereof.

10. The imaging lens system of claim 9 , wherein the focal length of the imaging lens system is f, the focal length of the third lens element is f3, and the following condition is satisfied:
f 3/ f<− 10.

11. The imaging lens system of claim 10 , wherein an equivalent air distance between the image-side surface of the fifth lens element and an image surface is BFL, a total axial distance of the air gaps between every two adjacent lens elements with refractive power is ΣAT, and the following condition is satisfied:
1.1<Σ AT/BFL< 1.75.

12. The imaging lens system of claim 1 , wherein the curvature radius of the object-side surface of the second lens element is R3, the focal length of the imaging lens system is f, and the following condition is satisfied:
| R 3|/ f< 3.0.

13. The imaging lens system of claim 1 , wherein a distance in parallel with an optical axis from an axial vertex on the object-side surface of the fourth lens element to a maximum effective diameter position on the object-side surface of the fourth lens element is SAG41, the central thickness of the fourth lens element is CT4, and the following condition is satisfied:
| SAG 41|/ CT 4<0.25.

14. The imaging lens system of claim 1 , wherein the third lens element has at least three inflection points.

15. The imaging lens system of claim 1 , wherein the object-side surface of the second lens element has at least one concave shape in an off-axis region thereof.

16. The imaging lens system of claim 15 , wherein a distance in parallel with an optical axis from an axial vertex on the object-side surface of the fifth lens element to a maximum effective diameter position on the object-side surface of the fifth lens element is SAG51, the axial distance between the fourth lens element and the fifth lens element is T45, and the following condition is satisfied:
0.80<| SAG 51|/ T 45<1.10.

17. The imaging lens system of claim 16 , wherein a central thickness of the second lens element is CT2, a central thickness of the third lens element is CT3, the central thickness of the fourth lens element is CT4, and the following condition is satisfied:
0.70<( CT 2+ CT 3)/ CT 4<1.00.

18. An image capturing device comprising:
the imaging lens system of claim 1 ; and
an image sensor, wherein the image sensor is disposed on an image surface of the imaging lens system.

19. An imaging 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 with negative 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 third lens element with negative 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, an object-side surface and the image-side surface thereof being aspheric, the image-side surface having at least one inflection point in an off-axis region thereof;
a fourth lens element with positive refractive power having an object-side surface being concave in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof, the object-side surface and the image-side surface thereof being aspheric; and
a fifth lens element with negative refractive power having an object-side surface being concave in a paraxial region thereof and an image-side surface being concave in a paraxial reg

Assignees

• Largan Precision Co Ltd

Inventors

• Lin Cheng-Chen
• Tang Hsiang-Chi
• Chen Kuan-Ming
• Chen Wei-Yu

Classifications

• H04N23/54

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

• H04N5/2254

  Electricity · mapped topic

• H04N5/2253

  Electricity · mapped topic

• G02B9/60

  having five components only · CPC title

• G02B13/0045 Primary

  having five or more lenses · CPC title