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EP-4741904-A2 - IMAGING LENS SYSTEM, IMAGE CAPTURING UNIT AND ELECTRONIC DEVICE

EP4741904A2EP 4741904 A2EP4741904 A2EP 4741904A2EP-4741904-A2

Abstract

An imaging lens system includes eight lens elements (E1, E2, E3, E4, E5, E6, E7, E8) which are, in order from an object side to an image side along an optical path: a first lens element (E1), a second lens element (E2), a third lens element (E3), a fourth lens element (E4), a fifth lens element (E5), a sixth lens element (E6), a seventh lens element (E7) and an eighth lens element (E8). Each of the eight lens elements (E1, E2, E3, E4, E5, E6, E7, E8) has an object-side surface facing toward the object side and an image-side surface facing toward the image side. The object-side surface of the third lens element (E3) is concave in a paraxial region thereof. When specific conditions are satisfied, the requirements of wide field of view, compact size and high image quality can be met by the imaging lens system, simultaneously.

Inventors

  • HSUEH, CHUN-CHE
  • CHO, MENG-KUAN

Assignees

  • LARGAN Precision Co., Ltd.

Dates

Publication Date
20260513
Application Date
20220627

Claims (20)

  1. An imaging lens system comprising eight lens elements (E1, E2, E3, E4, E5, E6, E7, E8), the eight lens elements (E1, E2, E3, E4, E5, E6, E7, E8) being, in order from an object side to an image side along an optical path, a first lens element (E1), a second lens element (E2), a third lens element (E3), a fourth lens element (E4), a fifth lens element (E5), a sixth lens element (E6), a seventh lens element (E7) and an eighth lens element (E8), and each of the eight lens elements (E1, E2, E3, E4, E5, E6, E7, E8) having an object-side surface facing toward the object side and an image-side surface facing toward the image side; wherein the object-side surface of the third lens element (E3) is concave in a paraxial region thereof, the object-side surface of the fourth lens element (E4) is convex in a paraxial region thereof, the fifth lens element (E5) has negative refractive power, and the object-side surface of the sixth lens element (E6) is convex in a paraxial region thereof; wherein the imaging lens system further comprises an aperture stop (ST) located between the third lens element (E3) and the fourth lens element (E4); wherein an f-number of the imaging lens system is FNO, a central thickness of the third lens element (E3) is CT3, a focal length of the imaging lens system is f, an axial distance between the first lens element (E1) and the second lens element (E2) is T12, a sum of axial distances between each of all adjacent lens elements of the imaging lens system is ΣAT, an axial distance between the object-side surface of the first lens element (E1) and the image-side surface of the eighth lens element (E8) is TD, and the following conditions are satisfied: 1.20 < FNO ≤ 1.70 ; 0.26 < CT 3 / f < 2.20 ; 0.40 < T 12 / f < 1.20 ; and 0.23 < ΣAT / TD < 0.50 .
  2. The imaging lens system of claim 1, wherein the image-side surface of the second lens element (E2) is concave in a paraxial region thereof, and the image-side surface of the sixth lens element (E6) is convex in a paraxial region thereof; wherein a central thickness of the fourth lens element (E4) is CT4, a central thickness of the fifth lens element (E5) is CT5, an axial distance between the fourth lens element (E4) and the fifth lens element (E5) is T45, the axial distance between the object-side surface of the first lens element (E1) and the image-side surface of the eighth lens element (E8) is TD, and the following condition is satisfied: 0.09 < CT 4 + T 45 + CT 5 / TD < 0.20 .
  3. The imaging lens system of claim 1, wherein the object-side surface of the first lens element (E1) is convex in a paraxial region thereof; wherein an Abbe number of the fourth lens element (E4) is V4, and the following condition is satisfied: 32.0 < V 4 < 72.0 .
  4. The imaging lens system of claim 1, wherein a refractive index of the eighth lens element (E8) is N8, the sum of axial distances between each of all adjacent lens elements of the imaging lens system is ΣAT, an axial distance between the fifth lens element (E5) and the sixth lens element (E6) is T56, and the following conditions are satisfied: 1.60 < N 8 < 2.00 ; and 3.00 < ΣAT / T 56 ≤ 71.55 .
  5. The imaging lens system of claim 1, the central thickness of the third lens element (E3) is CT3, the focal length of the imaging lens system is f, an Abbe number of the eighth lens element (E8) is V8, and the following conditions are satisfied: 0.30 < CT 3 / f < 1.50 ; and 12.0 < V 8 < 40.0 .
  6. The imaging lens system of claim 1, wherein a refractive index of the fourth lens element (E4) is N4, a refractive index of the fifth lens element (E5) is N5, and the following condition is satisfied: 1.63 < N 4 + N 5 / 2 < 1.95 .
  7. The imaging lens system of claim 1, wherein the seventh lens element (E7) has negative refractive power; wherein the focal length of the imaging lens system is f, a composite focal length of the seventh lens element (E7) and the eighth lens element (E8) is f78, and the following condition is satisfied: − 1.00 < f / f 78 < 0.10 .
  8. The imaging lens system of claim 1, wherein the object-side surface of the second lens element (E2) is convex in a paraxial region thereof; wherein a curvature radius of the object-side surface of the sixth lens element (E6) is R11, a curvature radius of the image-side surface of the sixth lens element (E6) is R12, and the following condition is satisfied: R 11 + R 12 / R 11 − R 12 < 0.55 .
  9. The imaging lens system of claim 1, wherein the image-side surface of the seventh lens element (E7) has at least one inflection point; wherein a curvature radius of the object-side surface of the first lens element (E1) is R1, a curvature radius of the image-side surface of the first lens element (E1) is R2, and the following condition is satisfied: 0.00 < R 1 + R 2 / R 1 − R 2 < 3.00 .
  10. An image capturing unit (100), comprising: the imaging lens system of claim 1; and an image sensor (103) disposed on an image surface (IMG) of the imaging lens system.
  11. An electronic device (200), comprising: the image capturing unit (100) of claim 10.
  12. An imaging lens system comprising eight lens elements (E1, E2, E3, E4, E5, E6, E7, E8), the eight lens elements (E1, E2, E3, E4, E5, E6, E7, E8) being, in order from an object side to an image side along an optical path, a first lens element (E1), a second lens element (E2), a third lens element (E3), a fourth lens element (E4), a fifth lens element (E5), a sixth lens element (E6), a seventh lens element (E7) and an eighth lens element (E8), and each of the eight lens elements (E1, E2, E3, E4, E5, E6, E7, E8) having an object-side surface facing toward the object side and an image-side surface facing toward the image side; wherein the object-side surface of the second lens element (E2) is convex in a paraxial region thereof, the object-side surface of the third lens element (E3) is concave in a paraxial region thereof, the fifth lens element (E5) has negative refractive power, the object-side surface of the sixth lens element (E6) is convex in a paraxial region thereof, and the eighth lens element (E8) has negative refractive power; wherein an f-number of the imaging lens system is FNO, a central thickness of the third lens element (E3) is CT3, a focal length of the imaging lens system is f, a focal length of the fifth lens element (E5) is f5, a curvature radius of the object-side surface of the third lens element (E3) is R5, an axial distance between the first lens element (E1) and the second lens element (E2) is T12, and the following conditions are satisfied: 1.20 < FNO < 2.00 ; 0.30 < CT 3 / f < 2.20 ; − 1.60 < f / f 5 < 0.00 ; f / R 5 < − 0.20 ; and 0.30 < T 12 / f < 1.15 .
  13. The imaging lens system of claim 12, wherein the image-side surface of the second lens element (E2) is concave in a paraxial region thereof, the sixth lens element (E6) has positive refractive power, and the image-side surface of the sixth lens element (E6) is convex in a paraxial region thereof; wherein the f-number of the imaging lens system is FNO, and the following condition is satisfied: 1.20 < FNO ≤ 1.65 .
  14. The imaging lens system of claim 12, wherein a sum of axial distances between each of all adjacent lens elements of the imaging lens system is ΣAT, an axial distance between the fifth lens element (E5) and the sixth lens element (E6) is T56, the focal length of the imaging lens system is f, a composite focal length of the fourth lens element (E4), the fifth lens element (E5) and the sixth lens element (E6) is f456, and the following conditions are satisfied: 3.00 < ΣAT / T 56 < 80.00 ; and 0.30 < f / f 456 < 1.00 .
  15. The imaging lens system of claim 12, wherein the axial distance between the first lens element (E1) and the second lens element (E2) is T12, the focal length of the imaging lens system is f, an Abbe number of the eighth lens element (E8) is V8, and the following conditions are satisfied: 0.45 < T 12 / f < 1.00 ; and 12.0 < V 8 < 40.0 .
  16. The imaging lens system of claim 12, the focal length of the imaging lens system is f, a focal length of the sixth lens element (E6) is f6, a composite focal length of the fourth lens element (E4) and the fifth lens element (E5) is f45, and the following conditions are satisfied: 0.20 < f / f 6 < 2.00 ; and 0.00 < f / f 45 < 1.80 .
  17. The imaging lens system of claim 12, wherein the focal length of the imaging lens system is f, a composite focal length of the seventh lens element (E7) and the eighth lens element (E8) is f78, the central thickness of the third lens element (E3) is CT3, a sum of central thicknesses of all lens elements (E1, E2, E3, E4, E5, E6, E7, E8) of the imaging lens system is ΣCT, and the following conditions are satisfied: − 0.90 < f / f 78 < 0.20 ; and 0.10 < CT 3 / ΣCT < 0.40 .
  18. The imaging lens system of claim 12, wherein the object-side surface of the fourth lens element (E4) is convex in a paraxial region thereof; wherein a central thickness of the sixth lens element (E6) is CT6, the focal length of the imaging lens system is f, and the following condition is satisfied: 0.40 < CT 6 / f < 0.90 .
  19. The imaging lens system of claim 12, wherein a refractive index of the fourth lens element (E4) is N4, a refractive index of the fifth lens element (E5) is N5, and the following condition is satisfied: 1.67 < N 4 + N 5 / 2 < 1.90 .
  20. The imaging lens system of claim 12, wherein the fourth lens element (E4) has positive refractive power; wherein an Abbe number of the fourth lens element (E4) is V4, and the following condition is satisfied: 38.0 < V 4 < 65.0 .

Description

BACKGROUND Technical Field The present disclosure relates to an imaging lens system, an image capturing unit and an electronic device, more particularly to an imaging lens system and an image capturing unit applicable to an electronic device. Description of Related Art With the development of semiconductor manufacturing technology, the performance of image sensors has improved, and the pixel size thereof has been scaled down. Therefore, featuring high image quality becomes one of the indispensable features of an optical system nowadays. Furthermore, due to the rapid changes in technology, electronic devices equipped with optical systems are trending towards multi-functionality for various applications, and therefore the functionality requirements for the optical systems have been increasing. However, it is difficult for a conventional optical system to obtain a balance among the requirements such as high image quality, low sensitivity, a proper aperture size, miniaturization and a desirable field of view. SUMMARY According to one aspect of the present disclosure, an imaging lens system includes eight lens elements. The eight lens elements are, in order from an object side to an image side along an optical path, 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. The object-side surface of the third lens element is concave in a paraxial region thereof. When a curvature radius of the 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, a curvature radius of the object-side surface of the third lens element is R5, a central thickness of the third lens element is CT3, a focal length of the imaging lens system is f, a focal length of the fifth lens element is f5, and an axial distance between the first lens element and the second lens element is T12, the following conditions are satisfied: R3+R4/R3−R4<0.90; 0.26<CT3/f<2.20; −1.60<f/f5<0.00; f/R5<−0.20; and 0.30<T12/f<1.15. According to another aspect of the present disclosure, an imaging lens system includes eight lens elements. The eight lens elements are, in order from an object side to an image side along an optical path, 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. The object-side surface of the third lens element is concave in a paraxial region thereof. The object-side surface of the fourth lens element is convex in a paraxial region thereof. The fifth lens element has negative refractive power. When a curvature radius of the object-side surface of the fourth lens element is R7, a curvature radius of the image-side surface of the fifth lens element is R10, a central thickness of the third lens element is CT3, a focal length of the imaging lens system is f, an axial distance between the first lens element and the second lens element is T12, a sum of axial distances between each of all adjacent lens elements of the imaging lens system is ΣAT, and 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, the following conditions are satisfied: R7+R10/R7−R10<0.50; 0.26<CT3/f<2.20; 0.40<T12/f<1.20; and 0.23<ΣAT/TD<0.50. According to another aspect of the present disclosure, an imaging lens system includes eight lens elements. The eight lens elements are, in order from an object side to an image side along an optical path, 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. The object-side surface of the third lens element is concave in a paraxial region thereof. The fifth lens element has negative refractive power. When a curvature radius of the object-side surface of the third lens element is R5, a curvature radius of the object-side surface of the fourth lens element is R7, a curvature radius of the image-side surface of the fifth lens element is R10, 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, a central thickness of the sixth lens element is CT6, and a focal length of the imaging lens system is f, an f-number of the imaging lens system is FNO, the following conditio