OPTICAL IMAGING SYSTEM, IMAGING APPARATUS AND ELECTRONIC DEVICE

• US 20190187441A1
• Filed: 02/22/2019
• Published: 06/20/2019
• Est. Priority Date: 08/22/2016
• Status: Active Grant

• Current Assignee: Largan Precision Co Limited (Largan Precision)
• Original Assignee: Largan Precision Co Limited (Largan Precision)
• Inventors: Tang, Hsiang-Chi, Huang, Hsin-Hsuan
• Granted Patent: US 10,746,968 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 13/0045 having five or more lenses
• CPC Class Codes: G02B 13/18 with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration G02B13/002 takes precedence
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 5/005 Diaphragms for cameras G03B9/02
• CPC Class Codes: G02B 5/208 for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
• CPC Class Codes: G02B 9/62 having six components only

Abstract

An optical imaging system includes, in order from an object side to an image side: a first lens element having positive refractive power, a second lens element having negative refractive power, a third lens element, a fourth lens element, a fifth lens element having both an object-side surface and an image-side surface being aspheric, and a sixth lens element having both an object-side surface and an image-side surface being aspheric, wherein the optical imaging system has a total of six lens elements; at least one lens element among the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, and the sixth lens element has at least one inflection point.

Claims

1. An optical imaging system comprising six lens elements, the six lens elements being, 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, a fifth lens element and a sixth lens element;

wherein each of the six lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side, and at least one of the six lens elements comprises at least one inflection point;

wherein an axial distance between the object-side surface of the first lens element and an image surface is TL, an entrance pupil diameter of the optical imaging system is EPD, a half of the maximal field of view of the optical imaging system is HFOV, and the following conditions are satisfied;

1.0<

TL/EPD<

1.9;

0.20<

tan(HFOV)<

0.50; and

3.0 [mm]<

TL<

7.0 [mm].

2. The optical imaging system of claim 1, wherein the first lens element has positive refractive power and the second lens element has negative refractive power.

3. The optical imaging system of claim 1, wherein the third lens element has negative refractive power, the object-side surface of the third lens element is convex in a paraxial region thereof and the image-side surface of the third lens element is concave in a paraxial region thereof.

4. The optical imaging system of claim 1, wherein there is an air gap between each of adjacent lens elements of the optical imaging system, a focal length of the first lens element is f1, a focal length of the third lens element is f3, and the following condition is satisfied:

|f1/f3|<

1.0.

5. The optical imaging system of claim 1, wherein the image-side surface of the second lens element is concave in a paraxial region thereof, the image-side surface of the sixth lens element is aspheric and the object-side surface of the fifth lens element is concave in a paraxial region thereof.

6. The optical imaging system of claim 1, wherein the image-side surface of the sixth lens element is concave in a paraxial region thereof, the entrance pupil diameter of the optical imaging system is EPD, a maximum image height of the optical imaging system is ImgH, and the following condition is satisfied:

1.15<

EPD/ImgH<

2.0.

7. The optical imaging system of claim 1, wherein an axial distance between the image-side surface of the sixth lens element and the image surface is BL, a central thickness of the first lens element is CT1, and the following condition is satisfied:

0.20<

BL/CT1<

0.90.

8. The optical imaging system of claim 1, wherein a central thickness of the third lens element is smaller than a central thickness of the sixth lens element.

9. An optical imaging system comprising six lens elements, the six lens elements being, 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, a fifth lens element and a sixth lens element;

wherein each of the six lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side, and at least one of the six lens elements comprises at least one inflection point;

wherein an axial distance between the object-side surface of the first lens element and an image surface is TL, an entrance pupil diameter of the optical imaging system is EPD, a half of the maximal field of view of the optical imaging system is HFOV, a curvature radius of the object-side surface of the first lens element is R1, a central thickness of the first lens element is CT1, and the following conditions are satisfied;

1.0<

TL/EPD<

1.9;

0.20<

tan(HFOV)<

0.50; and

0.70<

R1/CT1<

1.50.

10. The optical imaging system of claim 9, wherein the fifth lens element has negative refractive power.

11. The optical imaging system of claim 9, wherein there is an air gap between each of adjacent lens elements of the optical imaging system, the sixth lens element has positive refractive power.

12. The optical imaging system of claim 9, wherein the image-side surface of the sixth lens element is concave in a paraxial region thereof and the image-side surface of the sixth lens element has at least one convex shape in an off-axis region thereof.

13. The optical imaging system of claim 9, wherein the sixth lens element has at least one inflection point, a vertical distance between a maximum effective diameter position on the object-side surface of the first lens element and an optical axis is Y11, a maximum image height of the optical imaging system is ImgH, and the following condition is satisfied:

0.65<

Y11/ImgH<

1.0.

14. The optical imaging system of claim 9, wherein a central thickness of the first lens element is CT1, a central thickness of the second lens element is CT2, a central thickness of central thickness of the third lens element is CT3, a central thickness of the fourth lens element is CT4, a central thickness of the fifth lens element is CT5, a central thickness of the sixth lens element is CT6, and the following condition is satisfied:

0.10<

(CT2+CT3+CT4+CT5)/(CT1+CT6)<

1.20.

15. The optical imaging system of claim 9, wherein a sum of all axial distances between adjacent lens elements of the optical imaging system is Σ

AT, an axial distance between the third lens element and the fourth lens element is T34, a vertical distance between a maximum effective diameter position on the object-side surface of the first lens element and an optical axis is Y11, a vertical distance between a maximum effective diameter position on the image-side surface of the sixth lens element and the optical axis is Y62, and the following conditions are satisfied;

1.05<

Σ

AT/T34<

4.0; and

0.80<

Y11/Y62<

1.35.

16. The optical imaging system of claim 9, further comprising a reflective element disposed on the object side of the first lens element along an optical axis direction, and the sixth lens element has at least one inflection point.

17. An imaging apparatus, comprising the optical imaging system of claim 9 and an image sensor disposed on the image surface of the optical imaging system.

18. An electronic device, comprising the imaging apparatus of claim 17.

19. An optical imaging system comprising six lens elements, the six lens elements being, 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, a fifth lens element and a sixth lens element;

wherein each of the six lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side;

wherein the image-side surface of the fifth lens element is aspheric, the image-side surface of the sixth lens element is aspheric, at least one of the six lens elements has at least one inflection point;

a focal length of the optical imaging system is f, an entrance pupil diameter of the optical imaging system is EPD, an axial distance between the object-side surface of the first lens element and an image surface is TL, and the following conditions are satisfied;

1.0<

f/EPD<

1.55; and

0.80<

f/TL<

1.10.

20. The optical imaging system of claim 19, wherein the first lens element has positive refractive power, the third lens element has negative refractive power, the axial distance between the object-side surface of the first lens element and the image surface is TL, and the following condition is satisfied:

3.0 [mm]<

TL<

7.0 [mm].

21. The optical imaging system of claim 19, wherein the image-side surface of the fifth lens element is concave in a paraxial region thereof.

22. The optical imaging system of claim 19, wherein there is an air gap between each of adjacent lens elements of the optical imaging system, a half of the maximal field of view of the optical imaging system is HFOV, and the following condition is satisfied:

0.20<

tan(HFOV)<

0.50.

23. The optical imaging system of claim 19, wherein 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:

−

2.0<

(R6+R7)/(R6−

R7)<

0.

24. The optical imaging system of claim 19, wherein a vertical distance between an off-axial critical point on the image-side surface of the sixth lens element and an optical axis is Yc62, the focal length of the optical imaging system is f, and the following condition is satisfied:

0.05<

Yc62/f<

0.70.

25. The optical imaging system of claim 19, wherein a sum of all axial distances between adjacent lens elements of the optical imaging system is Σ

AT, an axial distance between the third lens element and the fourth lens element is T34, and the following condition is satisfied;

1.10<

Σ

AT/T34<

1.80.

26. The optical imaging system of claim 19, wherein the sixth lens element has at least one inflection point, a curvature radius of the object-side surface of the sixth lens element is R11, a curvature radius of the image-side surface of the sixth lens element is R12, and the following condition is satisfied:

−

0.10<

(R11−

R12)/(R11+R12)<

0.35.