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CN-116953888-B - Imaging lens

CN116953888BCN 116953888 BCN116953888 BCN 116953888BCN-116953888-B

Abstract

An imaging lens sequentially comprises a first lens group, a second lens group, a third lens group and a fourth lens group from an object side to an image side along an optical axis. The first lens group has positive refractive power. The second lens group has negative refractive power and at least comprises two lenses with negative refractive power. The third lens group has positive refractive power, the third lens group comprises a 3-1 lens, a 3-2 lens and a 3-3 lens, the 3-1 lens has positive refractive power, and the 3-3 lens comprises a concave surface facing the object side. The fourth lens group has positive refractive power. The 3-1 lens, the 3-2 lens and the 3-3 lens are arranged in order from the object side to the image side along the optical axis, and the lenses are adjacent to each other.

Inventors

  • Dai Yumen

Assignees

  • 信泰光学(深圳)有限公司
  • 亚洲光学股份有限公司

Dates

Publication Date
20260512
Application Date
20220418

Claims (10)

  1. 1. An imaging lens, comprising: a first lens group having a positive refractive power, the first lens group including a 1-1 lens and a 1-2 lens, the 1-1 lens having a positive refractive power, the 1-2 lens having a positive refractive power, the 1-1 lens and the 1-2 lens being arranged in order from an object side to an image side along an optical axis; a second lens group having a negative refractive power, the second lens group including at least two lenses having a negative refractive power, the second lens group including a 2-1 lens having a negative refractive power and a 2-2 lens having a negative refractive power, the 2-1 lens and the 2-2 lens being arranged in order from the object side to the image side along the optical axis; A third lens group having positive refractive power, the third lens group including a 3-1 lens, a 3-2 lens, a 3-3 lens, and a 3-4 lens, the 3-1 lens having positive refractive power, the 3-2 lens having positive refractive power, the 3-3 lens having negative refractive power and including a concave surface facing the object side, the 3-4 lens having negative refractive power, and A fourth lens group having a positive refractive power, the fourth lens group including a 4-1 lens, the 4-1 lens having a positive refractive power; The first lens group, the second lens group, the third lens group and the fourth lens group are sequentially arranged from the object side to the image side along the optical axis; Wherein the 3-1 lens, the 3-2 lens and the 3-3 lens are sequentially arranged from the object side to the image side along the optical axis, and the lenses are adjacent to each other.
  2. 2. The imaging lens as claimed in claim 1, wherein: the 1-1 lens is a biconvex lens and comprises a convex surface facing the object side and another convex surface facing the image side, and the 1-2 lens comprises a convex surface facing the object side; The 2-1 lens comprises a concave surface facing the image side, and the 2-2 lens comprises a concave surface facing the object side; The 3-4 lens is arranged between the 3-3 lens and the fourth lens group, the 3-1 lens is a biconvex lens and comprises a convex surface facing the object side and another convex surface facing the image side, the 3-2 lens comprises a convex surface facing the object side, the 3-3 lens is a biconcave lens and further comprises another concave surface facing the image side, and the 3-4 lens is a meniscus lens and comprises a convex surface facing the object side and a concave surface facing the image side; the 4-1 lens includes a convex surface facing the object side.
  3. 3. The imaging lens as claimed in claim 2, wherein the fourth lens group further comprises a 4-2 lens disposed between the third lens group and the 4-1 lens, wherein: The 1-2 lens is a meniscus lens and further comprises a concave surface facing the image side; The 2-1 lens is a meniscus lens and further comprises a convex surface facing the object side; the 2-2 lens is a meniscus lens and further comprises a convex surface facing the image side; the 3-2 lens is a meniscus lens and further comprises a concave surface facing the image side; The 4-1 lens is a biconvex lens and further comprises another convex surface facing the image side, and The 4-2 lens is a meniscus lens with negative refractive power and comprises a concave surface facing the object side and a convex surface facing the image side.
  4. 4. The imaging lens as claimed in claim 2, wherein the first lens group further comprises a 1-3 lens disposed between the object side and the 1-1 lens, wherein: the 3-2 lens is a biconvex lens and further comprises another convex surface facing the image side; the 4-1 lens is a meniscus lens and further comprises a concave surface facing the image side, and The 1-3 lens is a meniscus lens with negative refractive power and comprises a convex surface facing the object side and a concave surface facing the image side.
  5. 5. The imaging lens as claimed in claim 4, wherein: The 1-2 lens is a biconvex lens and further comprises another convex surface facing the image side; The 2-1 lens is a biconcave lens and further comprises another concave surface facing the object side, and The 2-2 lens is a biconcave lens and further comprises another concave surface facing the image side.
  6. 6. The imaging lens as claimed in claim 4, wherein the second lens group further comprises a 2-3 lens disposed between the 2-2 lens and the third lens group, wherein: The 1-2 lens is a meniscus lens and further comprises a concave surface facing the image side; The 2-1 lens is a meniscus lens and further comprises a convex surface facing the object side; The 2-2 lens is a meniscus lens and further comprises a convex surface facing the image side, and The 2-3 lens is a meniscus lens with positive refractive power and comprises a convex surface facing the object side and a concave surface facing the image side.
  7. 7. The imaging lens as claimed in claim 1, wherein the third lens group further comprises an aperture stop disposed between the second lens group and the 3-1 lens.
  8. 8. The imaging lens as claimed in claim 1, wherein the lens group spacing is changeable along the optical axis to zoom the imaging lens from a wide-angle end to a middle end and then to a telephoto end to change a focal length, the fourth lens group being movable along the optical axis to perform focusing.
  9. 9. The imaging lens as claimed in claim 1, wherein the imaging lens satisfies at least one of the following conditions: -0.34 degree/mm. Ltoreq. FOV/f 1. Ltoreq.0.49 degree/mm; -0.36 ≤ fG1/f1 ≤ 0.68; -0.13 ≤ fG2/fG23 ≤ 0.55; 18 ≤ TTL/TG34 ≤ 74; Wherein FOV is the maximum field of view of the imaging lens, f1 is the effective focal length of the lens closest to the object side, fG1 is the effective focal length of the first lens group, fG2 is the effective focal length of the second lens group, fG23 is the effective focal length of the lens closest to the image side in the second lens group, TTL is the distance between the object side surface of the lens closest to the object side in the first lens group and the imaging surface along the optical axis, and TG34 is the thickness of the lens closest to the image side in the third lens group along the optical axis.
  10. 10. The imaging lens as claimed in claim 1, wherein the imaging lens satisfies at least one of the following conditions: 90 ≤ VdG1+VdG3 ≤ 107; -3.9 ≤ (L1R1×L1R2)/(L2R1×L2R2) ≤ -0.05; 65 ≤ VdG31+VdG34 ≤ 100; wherein VdG is the average abbe number of all lenses of the first lens group, vdG is the average abbe number of all lenses of the third lens group, L1R1 is the radius of curvature of the object side of the lens closest to the object side, L1R2 is the radius of curvature of the image side of the lens closest to the object side, L2R1 is the radius of curvature of the object side of the lens second closest to the object side, L2R2 is the radius of curvature of the image side of the lens second closest to the object side, vdG31 is the abbe number of the lens closest to the object side in the third lens group, vdG is the abbe number of the lens closest to the image side in the third lens group.

Description

Imaging lens Technical Field The invention relates to an imaging lens. Background Most of the known monitoring cameras do not have a zooming function, but with the development of industrial automation and the internet of things, the requirements of people on the monitoring cameras are more and more, especially the requirements of miniaturization, high resolution, low cost and high zooming magnification are higher and more, the known imaging lens cannot meet the requirements of the current monitoring cameras, and an imaging lens with another new architecture is needed to meet the requirements of the miniaturization, high resolution, low cost and high zooming magnification at the same time. Disclosure of Invention The technical problem to be solved by the invention is to provide an imaging lens which has short total length, high resolution, low cost and high zoom ratio, but has good optical performance. The invention provides an imaging lens which comprises a first lens group, a second lens group, a third lens group and a fourth lens group. The first lens group has positive refractive power. The second lens group has negative refractive power and at least comprises two lenses with negative refractive power. The third lens group has positive refractive power, the third lens group comprises a 3-1 lens, a 3-2 lens and a 3-3 lens, the 3-1 lens has positive refractive power, and the 3-3 lens comprises a concave surface facing the object side. The fourth lens group has positive refractive power. The first lens group, the second lens group, the third lens group and the fourth lens group are sequentially arranged from an object side to an image side along the optical axis. The 3-1 lens, the 3-2 lens and the 3-3 lens are arranged in order from the object side to the image side along the optical axis, and the lenses are adjacent to each other. When the imaging lens of the invention meets the above characteristics and does not need other additional characteristics or conditions, the basic functions of the imaging lens of the invention can be achieved. The first lens group comprises a 1-1 lens and a 1-2 lens, wherein the 1-1 lens is a biconvex lens and has positive refractive power, one convex surface faces towards the object side and the other convex surface faces towards the image side, and the 1-2 lens has positive refractive power and has one convex surface facing towards the object side. The second lens group comprises a 2-1 lens and a 2-2 lens, wherein the 2-1 lens has negative refractive power and comprises a concave surface facing the image side, and the 2-2 lens has negative refractive power and comprises a concave surface facing the object side. The third lens group may further include a 3-4 lens disposed between the 3-3 lens and the fourth lens group, wherein the 3-1 lens is a biconvex lens and includes a convex surface facing the object side and another convex surface facing the image side, the 3-2 lens has a positive refractive power and includes a convex surface facing the object side, the 3-3 lens is a biconcave lens having a negative refractive power and may further include another concave surface facing the image side, and the 3-4 lens is a meniscus lens having a negative refractive power and includes a convex surface facing the object side and a concave surface facing the image side. The fourth lens group comprises a 4-1 lens, wherein the 4-1 lens has positive refractive power and comprises a convex surface facing the object side. The 1-1 lenses and the 1-2 lenses are sequentially arranged from an object side to an image side along the optical axis. The 2-1 lenses and the 2-2 lenses are sequentially arranged from an object side to an image side along the optical axis. The fourth lens group may further include a 4-2 lens disposed between the third lens group and the 4-1 lens, wherein the 1-2 lens is a meniscus lens and may further include a concave surface facing the image side. The 2-1 lens is a meniscus lens and may further include a convex surface facing the object side. The 2-2 lens is a meniscus lens and may further include a convex surface facing the image side. The 3-2 lens is a meniscus lens and may further include a concave surface facing the image side. The 4-1 lens is a biconvex lens and may further include another convex surface facing the image side. The 4-2 lens is a meniscus lens with negative refractive power and comprises a concave surface facing the object side and a convex surface facing the image side. The first lens group may further include a 1-3 lens disposed between the object side and the 1-1 lens, wherein the 3-2 lens is a biconvex lens, and may further include another convex surface facing the image side. The 4-1 lens is a meniscus lens and may further include a concave surface facing the image side. The 1-3 lens is a meniscus lens with negative refractive power and comprises a convex surface facing the object side and a concave surface facing the image side. Wherein the 1-2 le