IMAGING LENS SYSTEM, IMAGE CAPTURING UNIT AND ELECTRONIC DEVICE

• US 20200132969A1
• Filed: 04/01/2019
• Published: 04/30/2020
• Est. Priority Date: 10/24/2018
• Status: Active Grant

• Current Assignee: Largan Precision Co Limited (Largan Precision)
• Original Assignee: Largan Precision Co Limited (Largan Precision)
• Inventors: HUANG, Hsin-Hsuan
• Granted Patent: US 11,262,540 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 13/0045 having five or more lenses
• CPC Class Codes: G02B 13/0055 employing a special optical element
• CPC Class Codes: G02B 9/64 having more than six components
• CPC Class Codes: H01L 27/14627 Microlenses

Abstract

An imaging lens system includes eight lens elements which are, 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, a sixth lens element, a seventh lens element and an eighth lens element. Each of the eight lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. At least one lens element of the imaging lens system has at least one lens surface having at least one inflection point. The imaging lens system has a total of eight lens elements.

Claims

1. An imaging lens system comprising eight lens elements, the eight 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, a sixth lens element, a seventh lens element and an eighth lens element, and each of the eight lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;

wherein the first lens element has positive refractive power, at least one lens element of the imaging lens system has at least one lens surface having at least one inflection point, and the imaging lens system has a total of eight lens elements;

wherein a minimum value among Abbe numbers of all lens elements of the imaging lens system is Vmin, half of a maximum field of view of the imaging lens system is HFOV, a focal length of the imaging lens system is f, a focal length of the first lens element is f1, an entrance pupil diameter of the imaging lens system is EPD, an axial distance between the image-side surface of the eighth lens element and an image surface is BL, an axial distance between the object-side surface of the first lens element and the image-side surface of the eighth lens element is TD, and the following conditions are satisfied;

8.0<

Vmin<

22.5;

5.0 [deg.]<

HFOV<

25.0 [deg.];

0.80<

f/EPD<

2.20;

0<

BL/TD<

0.25; and

0.32<

f/f1<

3.80.

2. The imaging lens system of claim 1, wherein the second lens element has negative refractive power, the image-side surface of the second lens element is concave in a paraxial region thereof, and each of at least three lens elements of the imaging lens system has at least one lens surface having at least one inflection point.

3. The imaging lens system of claim 1, wherein the object-side surface of the first lens element is convex in a paraxial region thereof, the image-side surface of the seventh lens element is concave in a paraxial region thereof, and at least four lens elements of the imaging lens system are made of plastic material.

4. The imaging lens system of claim 1, wherein the minimum value among Abbe numbers of all lens elements of the imaging lens system is Vmin, and the following condition is satisfied:

10.0<

Vmin<

20.0.

5. The imaging lens system of claim 1, wherein an axial distance between the object-side surface of the first lens element and the image surface is TL, the entrance pupil diameter of the imaging lens system is EPD, and the following condition is satisfied:

0.90<

TL/EPD<

1.90.

6. The imaging lens system of claim 1, wherein each of at least four lens elements of the imaging lens system has an Abbe number smaller than 35.0.

7. The imaging lens system of claim 1, wherein a focal length of the fifth lens element is f5, a focal length of the eighth lens element is f8, and the following condition is satisfied:

−

0.50<

f8/f5<

9.0.

8. The imaging lens system of claim 1, wherein a sum of central thicknesses of all lens elements of the imaging lens system is Σ

CT, a sum of axial distances between each of all adjacent lens elements of the imaging lens system is Σ

AT, and the following condition is satisfied;

1.10<

Σ

CT/Σ

AT<

3.50.

9. The imaging lens system of claim 1, wherein 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 condition is satisfied:

0.50<

R1/CT1<

2.65.

10. The imaging lens system of claim 1, wherein an axial distance between the object-side surface of the first lens element and the image surface is TL, the focal length of the imaging lens system is f, a curvature radius of the object-side surface of the seventh lens element is R13, a curvature radius of the image-side surface of the seventh lens element is R14, and the following conditions are satisfied:

0.50<

TL/f<

1.10; and

(R13−

R14)/(R13+R14)<

5.0.

11. The imaging lens system of claim 1, wherein a maximum effective radius of the object-side surface of the first lens element is Y11, a maximum effective radius of the image-side surface of the eighth lens element is Y82, a maximum image height of the imaging lens system is ImgH, the focal length of the imaging lens system is f, a maximum value among refractive indices of all lens elements of the imaging lens system is Nmax, and the following conditions are satisfied:

0<

(|Y11−

Y82|+|Y82−

ImgH|)/f<

0.15; and

1.60<

Nmax<

1.72.

12. The imaging lens system of claim 1, wherein the focal length of the imaging lens system is f, a curvature radius of the object-side surface of one lens element of the imaging lens system is Ro, a curvature radius of the image-side surface of the lens element of the imaging lens system is Ri, and at least one lens element of the imaging lens system satisfies the following condition:

|f/Ro|+|f/Ri|<

0.50.

13. An image capturing unit, comprising:

the imaging lens system of claim 1; and

an image sensor disposed on the image surface of the imaging lens system.

14. An electronic device, comprising at least two image capturing units, the at least two image capturing units facing the same side, and the at least two image capturing units comprising:

a first image capturing unit, comprising the imaging lens system of claim 1 and a first image sensor, wherein the first image sensor is disposed on the image surface of the imaging lens system; and

a second image capturing unit, comprising an optical lens assembly and a second image sensor, wherein the second image sensor is disposed on an image surface of the optical lens assembly;

wherein a field of view of the first image capturing unit and a field of view of the second image capturing unit are different from each other by at least 20 degrees.

15. An imaging lens system comprising eight lens elements, the eight 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, a sixth lens element, a seventh lens element and an eighth lens element, and each of the eight lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;

wherein at least one lens element of the imaging lens system has at least one lens surface having at least one inflection point, and the imaging lens system has a total of eight lens elements;

wherein an Abbe number of the eighth lens element is V8, half of a maximum field of view of the imaging lens system is HFOV, a focal length of the imaging lens system is f, an entrance pupil diameter of the imaging lens 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;

8.0<

V8<

24.5;

5.0 [deg.]<

HFOV<

30.0 [deg.];

0.80<

f/EPD<

2.20; and

0.50<

TL/f<

1.30.

16. The imaging lens system of claim 15, wherein the first lens element has positive refractive power, the object-side surface of the first 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.

17. The imaging lens system of claim 15, wherein the image-side surface of the seventh lens element is concave in a paraxial region thereof.

18. The imaging lens system of claim 15, wherein the Abbe number of the eighth lens element is V8, and the following condition is satisfied:

8.0<

V8<

22.0.

19. The imaging lens system of claim 15, wherein the entrance pupil diameter of the imaging lens system is EPD, an axial distance between the image-side surface of the eighth lens element and the image surface is BL, and the following condition is satisfied:

4.50<

EPD/BL<

18.0.

20. The imaging lens system of claim 15, wherein an axial distance between the image-side surface of the eighth 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<

BL/CT1<

0.95.

21. The imaging lens system of claim 15, wherein a maximum effective radius of the object-side surface of the first lens element is Y11, a maximum image height of the imaging lens system is ImgH, the entrance pupil diameter of the imaging lens system is EPD, the focal length of the imaging lens system is f, a focal length of the fifth lens element is f5, and the following conditions are satisfied:

−

0.27<

(Y11−

ImgH)/EPD<

0; and

−

0.25<

f/f5<

1.50.

22. The imaging lens system of claim 15, further comprising an aperture stop, wherein the focal length of the imaging lens system is f, the entrance pupil diameter of the imaging lens system is EPD, an axial distance between the aperture stop and the image surface SL, the axial distance between the object-side surface of the first lens element and the image surface is TL, and the following conditions are satisfied:

1.0<

f/EPD<

2.0; and

0.50<

SL/TL<

0.95.

23. The imaging lens system of claim 15, wherein the focal length of the imaging lens system is f, half of the maximum field of view of the imaging lens system is HFOV, the entrance pupil diameter of the imaging lens system is EPD, and the following condition is satisfied:

0.20<

f×

tan(HFOV)/EPD<

1.0.

24. The imaging lens system of claim 15, wherein a maximum effective radius of the object-side surface of the first lens element is Y11, a maximum effective radius of the image-side surface of the eighth lens element is Y82, an axial distance between the image-side surface of the eighth lens element and the image surface is BL, the focal length of the imaging lens system is f, and the following condition is satisfied:

0<

(|Y11−

Y82|+BL)/f<

0.20.

25. An imaging lens system comprising eight lens elements, the eight 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, a sixth lens element, a seventh lens element and an eighth lens element, and each of the eight lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;

wherein at least one lens element of the imaging lens system has at least one lens surface having at least one inflection point, and the imaging lens system has a total of eight lens elements;

wherein a minimum value among Abbe numbers of all lens elements of the imaging lens system is Vmin, an axial distance between the object-side surface of the first lens element and an image surface is TL, a focal length of the imaging lens system is f, an axial distance between the image-side surface of the eighth lens element and the image surface is BL, an axial distance between the object-side surface of the first lens element and the image-side surface of the eighth lens element is TD, and the following conditions are satisfied;

8.0<

Vmin<

20.0;

0.50<

TL/f<

1.10; and

0<

BL/TD<

0.30.

26. The imaging lens system of claim 25, wherein an Abbe number of the first lens element is V1, an Abbe number of the second lens element is V2, an Abbe number of the third lens element is V3, an Abbe number of the fourth lens element is V4, an Abbe number of the fifth lens element is V5, an Abbe number of the sixth lens element is V6, an Abbe number of the seventh lens element is V7, an Abbe number of the eighth lens element is V8, an Abbe number of the i-th lens element is Vi, and the following condition is satisfied:

150.0<

Σ

Vi<

320.0, whereini=1,2,3,4,5,6,7,8.

27. The imaging lens system of claim 25, wherein the focal length of the imaging lens system is f, a focal length of the fifth lens element is f5, a focal length of the sixth lens element is f6, a vertical distance between a critical point on the image-side surface of the seventh lens element and an optical axis is Yc72, and the following conditions are satisfied:

−

0.50<

f/f5+f/f6<

1.0; and

0.02<

Yc72/f<

0.70.

28. The imaging lens system of claim 25, wherein the focal length of the imaging lens system is f, a focal length of the fifth lens element is f5, a focal length of the seventh lens element is f7, a curvature radius of the image-side surface of the fourth lens element is R8, and the following conditions are satisfied:

f5/f7<

0.50; and

−

1.50<

R8/f<

1.50.

29. The imaging lens system of claim 25, wherein the focal length of the imaging lens system is f, a maximum image height of the imaging lens system is ImgH, 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 conditions are satisfied:

2.10<

f/ImgH<

3.80; and

−

0.50<

(R11+R12)/(R11−

R12)<

15.0.

30. The imaging lens system of claim 25, wherein each of at least four lens elements of the imaging lens system has an Abbe number smaller than 35.0, a maximum effective radius of the object-side surface of the first lens element is Y11, a maximum effective radius of the object-side surface of the fifth lens element is Y51, a maximum effective radius of the image-side surface of the eighth lens element is Y82, and the following condition is satisfied:

0.70<

(Y82−

Y51)/(Y11−

Y51)<

2.50.

31. The imaging lens system of claim 25, wherein an entrance pupil diameter of the imaging lens system is EPD, a maximum image height of the imaging lens system is ImgH, a curvature radius of the object-side surface of the seventh lens element is R13, a curvature radius of the image-side surface of the seventh lens element is R14, and the following conditions are satisfied:

1.20<

EPD/ImgH<

2.80; and

(R13−

R14)/(R13+R14)<

5.0.

32. The imaging lens system of claim 25, wherein an Abbe number of the first lens element is V1, an Abbe number of the second lens element is V2, an Abbe number of the third lens element is V3, an Abbe number of the fourth lens element is V4, an Abbe number of the fifth lens element is V5, an Abbe number of the sixth lens element is V6, an Abbe number of the seventh lens element is V7, an Abbe number of the eighth lens element is V8, an Abbe number of the i-th lens element is Vi, a refractive index of the first lens element is N1, a refractive index of the second lens element is N2, a refractive index of the third lens element is N3, a refractive index of the fourth lens element is N4, a refractive index of the fifth lens element is N5, a refractive index of the sixth lens element is N6, a refractive index of the seventh lens element is N7, a refractive index of the eighth lens element is N8, a refractive index of the i-th lens element is Ni, a minimum value of Vi/Ni is (Vi/Ni)min, the axial distance between the object-side surface of the first lens element and the image surface is TL, a maximum image height of the imaging lens system is ImgH, and the following conditions are satisfied:

9.0<

(Vi/Ni)min<

11.80, wherein i=1,2,3,4,5,6,7,8;

4.0 [mm]<

TL<

8.0 [mm]; and

1.50 [mm]<

ImgH<

4.50 [mm].