Optical lens

Abstract

The application provides an optical lens, the number of lenses with optical power of the optical lens is four, the optical lens comprises a lens group, a spacer element group and a lens barrel, wherein the inner diameter d0s of the object side end surface of the lens barrel, the inner diameter d0m of the image side end surface of the lens barrel and the on-axis distance TD from the object side surface of the first lens to the image side surface of the fourth lens satisfy: 0.40<(d0s-d0m) / TD<1.10; the inner diameter d0s of the object side end surface of the lens barrel, the inner diameter d1s of the object side surface of the first spacer element and the radius of curvature R2 of the image side surface of the first lens satisfy: 4.20<(d0s-d1s) / R2<8.95. The application solves the problems of serious front end stray light and unstable assembly of a wide-angle optical lens in the prior art.

Description

Technical Field

[0001] This invention relates to the field of optical imaging equipment technology, and more specifically, to an optical lens. Background Technology

[0002] In recent years, the drone market has developed rapidly, with miniaturization and lightweighting becoming one of the development directions for drones. As one of the core systems of drones, obstacle avoidance systems also need to adapt to this development trend. Drone obstacle avoidance systems have strict requirements on the wide-angle, weight, and size of the optical lenses they use, and the optical lenses used in obstacle avoidance systems also need to meet the requirements of miniaturization and wide-angle.

[0003] To capture more light and achieve a wider field of view, wide-angle lenses typically have a larger first lens. However, this larger effective diameter results in a significant difference in the radial dimensions of the first and second lenses, leading to decreased stability in the lens assembly. Therefore, controlling the dimensions of the lens barrel, lens groups, front lens, and spacer elements to effectively block stray light and improve front-end assembly stability while maintaining a wide angle and high light transmission is a crucial issue. Summary of the Invention

[0004] The main objective of this invention is to provide an optical lens to solve the problems of severe stray light at the front end and unstable assembly in existing wide-angle optical lenses.

[0005] To achieve the above object, according to one aspect of the present invention, an optical lens is provided. The number of lenses with optical power in the optical lens is four. The optical lens includes: a lens group, from the object side to the image side of the optical lens, the lens group includes a first lens to a fourth lens arranged sequentially and spaced apart; the first lens has a negative optical power, the paraxial region of the object side surface of the first lens is convex, and the image side surface of the first lens is concave; the second lens has a positive optical power, the paraxial region of the object side surface of the second lens is convex, and the image side surface of the second lens is convex; the third lens has a negative optical power, the paraxial region of the image side surface of the third lens is concave; the fourth lens has a positive optical power, the paraxial region of the object side surface of the fourth lens is convex, and the image side surface of the fourth lens is convex, and the outer diameter of the first lens is greater than the outer diameter of the fourth lens; a spacer element group, the spacer element group at least includes a first spacer element located between the first lens and the second lens and closest to the image side surface of the first lens; a lens barrel, the lens group and the spacer element group are accommodated in the lens barrel, and the inner diameter of the object side end surface of the lens barrel is greater than the inner diameter of the image side end surface of the lens barrel; wherein, the inner diameter d0s of the object side end surface of the lens barrel, the inner diameter d0m of the image side end surface of the lens barrel, and the on-axis distance TD from the object side surface of the first lens to the image side surface of the fourth lens satisfy: 0.40 < (d0s - d0m) / TD < 1.10; the inner diameter d0s of the object side end surface of the lens barrel, the inner diameter d1s of the object side surface of the first spacer element, and the curvature radius R2 of the image side surface of the first lens satisfy: 4.20 < (d0s - d1s) / R2 < 8.95.

[0006] According to another aspect of the present invention, an optical lens is provided. The number of lenses with optical power in the optical lens is four. The optical lens includes: a lens group, from the object side to the image side of the optical lens, the lens group includes a first lens to a fourth lens arranged sequentially and spaced apart; the first lens has a negative optical power, the paraxial region of the object side surface of the first lens is convex, and the image side surface of the first lens is concave; the second lens has a positive optical power, the paraxial region of the object side surface of the second lens is convex, and the image side surface of the second lens is convex; the third lens has a negative optical power, the paraxial region of the image side surface of the third lens is concave; the fourth lens has a positive optical power, the paraxial region of the object side surface of the fourth lens is convex, and the image side surface of the fourth lens is convex, and the outer diameter of the first lens is greater than the outer diameter of the fourth lens; a spacer element group, the spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens; a lens barrel, the lens group and the spacer element group are accommodated in the lens barrel, and the inner diameter of the object side end surface of the lens barrel is greater than the inner diameter of the image side end surface of the lens barrel; wherein, the effective radius DT32 of the image side surface of the third lens and the effective radius DT41 of the object side surface of the fourth lens satisfy: 0.90 < DT32 / DT41 < 1.00; the inner diameter d3m of the image side surface of the third spacer element and the effective radius DT41 of the object side surface of the fourth lens satisfy: 2.00 < d3m / DT41 < 2.50.

[0007] Furthermore, the air gap between the first lens and the second lens along the optical axis is greater than the air gap between any two adjacent lenses in the lens group along the optical axis. The distance EP01 between the object-side end face of the lens barrel and the object-side surface of the first spacer element along the optical axis, and the air gap T12 between the first lens and the second lens along the optical axis satisfy: 0.50 <EP01 / T12<0.95。

[0008] Furthermore, the spacer group includes at least a second spacer element located between the second lens and the third lens and in at least partial contact with the image side of the second lens. The inner diameter d2s of the object side of the second spacer element, the inner diameter d2m of the image side of the second spacer element, and the air gap T23 between the second lens and the third lens along the optical axis of the optical lens satisfy the following: 2.65 < |d2s-d2m| / T23 < 28.00.

[0009] Furthermore, the spacer element group includes at least a second spacer element located between the second lens and the third lens and in at least partial contact with the image-side surface of the second lens. The maximum thickness CP2 of the second spacer element along the optical axis of the optical lens and the air gap T23 between the second lens and the third lens along the optical axis satisfy: 12.25 <CP2 / T23<13.80。

[0010] Furthermore, the spacer group includes at least a third spacer located between the third lens and the fourth lens and in at least partial contact with the image side of the third lens. The maximum thickness of the third spacer along the optical axis of the optical lens is the smallest among the maximum thicknesses of all spacers in the spacer group along the optical axis. The effective focal length f3 of the third lens, the effective focal length f4 of the fourth lens, and the inner diameter d3s of the object side of the third spacer satisfy the following: -1.80 < (f3-f4) / d3s < -1.00.

[0011] Furthermore, the axial distance TD between the object side surface of the first lens and the image side surface of the fourth lens is greater than the distance L between the object side end face of the lens barrel and the image side end face of the lens barrel along the optical axis; the center thickness CT1 of the first lens along the optical axis and the distance EP01 between the object side end face of the lens barrel and the object side surface of the first spacer element along the optical axis satisfy the following condition: 0.20≤CT1 / EP01<0.40.

[0012] Furthermore, the spacer group includes at least a second spacer element located between the second lens and the third lens and in at least partial contact with the image side of the second lens. The outer diameter D2m of the image side of the second spacer element, the inner diameter d2s of the object side of the second spacer element, and the effective radius DT22 of the image side of the second lens satisfy the following: 1.50 < (D2m - d2s) / (2 × DT22) < 2.80.

[0013] Furthermore, the spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The air gap T34 between the third lens and the fourth lens along the optical axis direction of the optical lens and the maximum thickness CP3 of the third spacer element along the optical axis direction satisfy: 6.95 < T34 / CP3 < 8.60.

[0014] Furthermore, the spacer element group at least includes a second spacer element located between the second lens and the third lens and at least partially contacting the image side surface of the second lens, and a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The distance EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element along the optical axis direction of the optical lens and the effective focal length f3 of the third lens satisfy: -0.65 < EP23 / f3 < -0.30.

[0015] Furthermore, the spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The effective radius DT32 of the image side surface of the third lens and the effective radius DT41 of the object side surface of the fourth lens satisfy: 0.90 < DT32 / DT41 < 1.00; the inner diameter d3m of the image side surface of the third spacer element and the effective radius DT41 of the object side surface of the fourth lens satisfy: 2.00 < d3m / DT41 < 2.50.

[0016] Furthermore, the spacer element group at least includes a second spacer element located between the second lens and the third lens and at least partially contacting the image side surface of the second lens. The curvature radius R4 of the image side surface of the second lens and the inner diameter d2s of the object side surface of the second spacer element satisfy: -0.40 < R4 / d2s < -0.25; the maximum thickness CP2 of the second spacer element along the optical axis direction of the optical lens and the sagitta SAG22 of the image side surface of the second lens satisfy: -1.05 < CP2 / SAG22 < -0.85.

[0017] Furthermore, the spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The inner diameter d3s of the object side surface of the third spacer element and the inner diameter d0m of the image side end surface of the lens barrel satisfy: 0.40 < d3s / d0m < 1.00.

[0018] Furthermore, the spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The following relationships are satisfied between the radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f4 of the fourth lens: -0.65 < R8 / f4 ≤ -0.55; the following relationship is satisfied between the distance EP30 from the image side surface of the third spacer element to the image side end face of the lens barrel along the optical axis of the optical lens and the sag SAG42 of the image side surface of the fourth lens: -3.75 < EP30 / SAG42 < -1.55.

[0019] Furthermore, the spacer element group at least includes a second spacer element located between the second lens and the third lens and at least partially contacting the image side surface of the second lens, and a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The Abbe number of the third lens is less than half of the Abbe numbers of the other lenses of the lens group; the following relationship is satisfied between the central thickness CT3 of the third lens along the optical axis of the optical lens and the radius of curvature R6 of the image side surface of the third lens: 0.40 < CT3 / R6 < 0.55; the following relationship is satisfied between the inner diameter d3s of the object side surface of the third spacer element and the inner diameter d2m of the image side surface of the second spacer element: 0.85 < d3s / d2m < 1.40.

[0020] Furthermore, the spacer element group at least includes a second spacer element located between the second lens and the third lens and at least partially contacting the image side surface of the second lens. The following relationship is satisfied between the radius of curvature R2 of the image side surface of the first lens and the air gap T12 from the first lens to the second lens along the optical axis of the optical lens: 0.30 < R2 / T12 < 0.65; the following relationship is satisfied between the on-axis distance TD from the object side surface of the first lens to the image side surface of the fourth lens and the maximum thickness CP2 of the second spacer element along the optical axis: 9.50 < TD / CP2 < 10.75.

[0021] Applying the technical solution of this invention, the optical lens has four lenses with optical power. The optical lens includes a lens group, a spacer element group, and a lens barrel. From the object side to the image side of the optical lens, the lens group includes a first lens to a fourth lens arranged sequentially at intervals. The first lens has negative optical power, the paraxial region of the object side of the first lens is convex, and the image side of the first lens is concave. The second lens has positive optical power, the paraxial region of the object side of the second lens is convex, and the image side of the second lens is convex. The third lens has negative optical power, the paraxial region of the image side of the third lens is concave. The fourth lens has positive optical power, the paraxial region of the object side of the fourth lens is convex, and the image side of the fourth lens is convex. The outer diameter of the first lens is larger than that of the fourth lens. The outer diameter; the spacer group includes at least a first spacer element located between the first lens and the second lens and closest to the image side surface of the first lens; the lens group and the spacer group are housed in the lens barrel, and the inner diameter of the object side end face of the lens barrel is greater than the inner diameter of the image side end face of the lens barrel; wherein, the inner diameter d0s of the object side end face of the lens barrel, the inner diameter d0m of the image side end face of the lens barrel, and the axial distance TD from the object side surface of the first lens to the image side surface of the fourth lens satisfy: 0.40 < (d0s - d0m) / TD < 1.10; the inner diameter d0s of the object side end face of the lens barrel, the inner diameter d1s of the object side surface of the first spacer element, and the radius of curvature R2 of the image side surface of the first lens satisfy: 4.20 < (d0s - d1s) / R2 < 8.95.

[0022] The optical lens of this application uses four lenses with optical power, arranged sequentially from the first to the fourth lens at intervals. The outer diameter of the first lens is larger than that of the fourth lens, and the inner diameter of the object-side end face of the lens barrel is larger than that of the image-side end face. In the optical lens of this application, the inner diameters of the object-side and image-side end faces of the lens barrel, as well as the total length of the lens group along the optical axis, satisfy 0.40 < (d0s - d0m) / TD < 1.10, ensuring the overall miniaturization of the wide-angle optical lens. However, to obtain more light and a larger field of view, the radial dimensions of the first and second lenses typically differ significantly, while the radial dimensions of the third and fourth lenses differ less, leading to a decrease in the assembly stability of the front end of the optical lens. By limiting (d0s - d1s) / R2 within a reasonable range, the relationship between the difference between the inner diameter of the object-side end face of the lens barrel and the inner diameter of the object-side surface of the first spacer element, and the radius of curvature of the image-side surface of the first lens can be constrained. This balances the dimensions of the lens barrel opening and the two front-end lenses, improving the assembly stability of the first and second lenses. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 A schematic diagram showing partial parameters of an optical lens according to any optional embodiment of the present invention is shown;

[0025] Figure 2 A schematic diagram of the structure of the optical lens according to Embodiment 1 of the present invention is shown;

[0026] Figure 3 A schematic diagram of the optical lens structure according to Embodiment 2 of the present invention is shown;

[0027] Figure 4 A schematic diagram of the optical lens of Embodiment 3 of the present invention is shown;

[0028] Figures 5 to 7 The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the optical lens of Embodiment 1 are shown respectively.

[0029] Figure 8 A schematic diagram of the optical lens of Embodiment 4 of the present invention is shown;

[0030] Figure 9 A schematic diagram of the optical lens of Embodiment 5 of the present invention is shown;

[0031] Figure 10 A schematic diagram of the optical lens of Embodiment Six of the present invention is shown;

[0032] Figures 11 to 13 The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the optical lens of Embodiment 4 are shown respectively.

[0033] Figure 14 A schematic diagram of the optical lens of Embodiment Seven of the present invention is shown;

[0034] Figure 15 A schematic diagram of the structure of the optical lens of Embodiment 8 of the present invention is shown;

[0035] Figure 16 A schematic diagram of the structure of the optical lens of Embodiment 9 of the present invention is shown;

[0036] Figures 17 to 19 The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the optical lens of Embodiment 7 are shown respectively.

[0037] Figures 20 to 21 The stray light path diagram, stray light energy intensity distribution diagram, stress distribution diagram, and second lens stress distribution diagram of the optical lens under the conditions of (d0s-d0m) / TD=0.93 and (d0s-d1s) / R2=4.46 of Embodiment 1 of the present invention are shown respectively.

[0038] Figures 22 to 23The stress distribution diagrams of the optical lens and the second lens under the conditions of (d0s-d0m) / TD=0.93 and (d0s-d1s) / R2=9.30, respectively, are shown.

[0039] Figures 24 to 25 The stray light path diagram, stray light energy intensity distribution diagram, stress distribution diagram, and stress distribution diagram of the optical lens of Comparative Example 2 under the conditions of (d0s-d0m) / TD=0.93 and (d0s-d1s) / R2=3.06 are shown respectively.

[0040] Figures 26 to 27 The stray light path diagram and stray light energy intensity distribution diagram of the optical lens of Embodiment 1 of the present invention are shown respectively;

[0041] Figures 28 to 29 The stray light path diagram and stray light energy intensity distribution diagram of the optical lens of Comparative Example 3 under the conditions of DT32 / DT41=0.96 and d3m / DT41=2.9 are shown respectively.

[0042] Figures 30 to 31 The stray light path diagram and stray light energy intensity distribution diagram of the optical lens of Comparative Example 4 under the conditions of DT32 / DT41=0.96 and d3m / DT41=1.0 are shown respectively.

[0043] Figure 32 A schematic diagram showing another portion of the parameters of the optical lens of any alternative embodiment of the present invention is illustrated.

[0044] The above figures include the following reference numerals:

[0045] P0, Lens tube; E1, First lens; P1, First spacer element; P1b, First auxiliary spacer element; P1c, First additional spacer element; E2, Second lens; P2, Second spacer element; E3, Third lens; P3, Third spacer element; E4, Fourth lens; S1, Object-side surface of the first lens; S2, Image-side surface of the first lens; S3, Object-side surface of the second lens; S4, Image-side surface of the second lens; S5, Object-side surface of the third lens; S6, Image-side surface of the third lens; S7, Object-side surface of the fourth lens; S8, Image-side surface of the fourth lens. Detailed Implementation

[0046] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0048] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0049] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0050] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not drawn strictly to scale.

[0051] In this paper, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of that convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of that concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The determination of the surface shape in the paraxial region can be based on the judgment method commonly used by those knowledgeable in the field, using the R value (R refers to the radius of curvature of the paraxial region, usually the R value in the lens data in optical software) to determine convexity or concavity. For the object-side surface, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave; for the image-side surface, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex.

[0052] To address the problems of severe stray light and unstable assembly in existing wide-angle optical lenses, this invention provides an optical lens.

[0053] First Implementation Method

[0054] like Figures 1 to 19As shown, the optical lens has four lenses with optical power. The optical lens includes a lens group, a spacer element group, and a lens barrel. From the object side to the image side of the optical lens, the lens group includes a first lens to a fourth lens arranged in sequence at intervals. The first lens has negative optical power, the paraxial region of the object side of the first lens is convex, and the image side of the first lens is concave. The second lens has positive optical power, the paraxial region of the object side of the second lens is convex, and the image side of the second lens is convex. The third lens has negative optical power, the paraxial region of the image side of the third lens is concave. The fourth lens has positive optical power, the paraxial region of the object side of the fourth lens is convex, and the image side of the fourth lens is convex. The outer diameter of the first lens is larger than the outer diameter of the fourth lens. The spacer element group includes at least a first spacer element located between the first lens and the second lens and closest to the image-side surface of the first lens; the lens group and the spacer element group are housed within a lens barrel, and the inner diameter of the object-side end face of the lens barrel is larger than the inner diameter of the image-side end face of the lens barrel; wherein, the inner diameter d0s of the object-side end face of the lens barrel, the inner diameter d0m of the image-side end face of the lens barrel, and the axial distance TD from the object-side surface of the first lens to the image-side surface of the fourth lens satisfy the following: 0.40 < (d0s - d0m) / TD < 1.10; the inner diameter d0s of the object-side end face of the lens barrel, the inner diameter d1s of the object-side surface of the first spacer element, and the radius of curvature R2 of the image-side surface of the first lens satisfy the following: 4.20 < (d0s - d1s) / R2 < 8.95.

[0055] The optical lens of this application uses four lenses with optical power, arranged sequentially from the first to the fourth lens at intervals. The outer diameter of the first lens is larger than that of the fourth lens, and the inner diameter of the object-side end face of the lens barrel is larger than that of the image-side end face. In the optical lens of this application, the inner diameters of the object-side and image-side end faces of the lens barrel, as well as the total length of the lens group along the optical axis, satisfy 0.40 < (d0s - d0m) / TD < 1.10, ensuring the overall miniaturization of the wide-angle optical lens. However, to obtain more light and a larger field of view, the radial dimensions of the first and second lenses typically differ significantly, while the radial dimensions of the third and fourth lenses differ less, leading to a decrease in the assembly stability of the front end of the optical lens. By limiting (d0s - d1s) / R2 within a reasonable range, the relationship between the difference between the inner diameter of the object-side end face of the lens barrel and the inner diameter of the object-side surface of the first spacer element, and the radius of curvature of the image-side surface of the first lens can be constrained. This balances the dimensions of the lens barrel opening and the two front-end lenses, improving the assembly stability of the first and second lenses.

[0056] Table 1 below and Figures 20 to 25 The stress distribution diagrams of the optical lenses of Example 1 and Comparative Examples 1 and 2, under the condition of (d0s-d1s) / R2 with different values, and the stress distribution diagram of the second lens are given, demonstrating the degree of deformation of the optical lenses.

[0057] Table 1

[0058]

[0059] When the optical lens of Comparative Example 1 satisfies (d0s-d0m) / TD=0.93 and (d0s-d1s) / R2=9.30, the stress distribution is as follows. Figure 22 and Figure 23 As shown, when (d0s-d1s) / R2 is too large, under the premise of low stray light, the step difference between the first and second lenses is too large, resulting in high stress concentration at the front end of the optical lens, especially the second lens, and a high risk of severe deformation, leading to unstable optical lens assembly. In Comparative Example 2, when the optical lens satisfies (d0s-d0m) / TD=0.93 and (d0s-d1s) / R2=3.06, the stress distribution is as follows... Figure 24 and Figure 25 As shown, when the value of (d0s-d1s) / R2 is too small, the step difference between the first lens and the second lens becomes smaller. The position where the structural part of the second lens contacts other components is too far from the effective diameter edge of the second lens. The structural part of the second lens forms a torque with the position where the force is applied. When subjected to assembly pressure, the second lens has a large deformation towards the object under the action of the torque, which leads to a decrease in imaging quality and affects the performance of the optical lens.

[0060] In embodiment 1 of this application, when (d0s-d0m) / TD=0.93 and (d0s-d1s) / R2=4.46, the stray light distribution and stress distribution are as follows: Figure 20 and Figure 21 As shown, the stress at the front end of the optical lens, especially at the second lens, is relatively small and evenly distributed with a gentle change, which greatly reduces the risk of deformation and improves assembly stability and structural strength. At the same time, the inner diameter of the object side of the first spacer element is reasonable, and the stray light energy of the optical lens is significantly reduced.

[0061] In this embodiment, the air gap between the first lens and the second lens along the optical axis of the optical lens is greater than the air gap between any two adjacent lenses in the lens group along the optical axis. The distance EP01 from the object-side end face of the lens barrel to the object-side surface of the first spacer element along the optical axis and the air gap T12 between the first lens and the second lens along the optical axis satisfy: 0.50 < EP01 / T12 < 0.95. If the value of EP01 / T12 is too large, the air gap between the first lens and the second lens along the optical axis is small, which is not conducive to the imaging quality and assembly stability of the first lens and the second lens group. If the value of EP01 / T12 is too small, the air gap between the first lens and the second lens along the optical axis is large, resulting in the light not being effectively converged by the second lens after passing through the first lens, affecting the imaging quality of the optical lens. By controlling EP01 / T12 within a reasonable range, the mutual relationship between the air gap between the first lens and the second lens on the optical axis and the distance from the object-side end face of the lens barrel to the first spacer element on the optical axis can be controlled, ensuring that the incident light is effectively collected and converged after passing through the first lens. At the same time, the air gap between the first lens and the second lens along the optical axis of the optical lens is relatively large, ensuring that the light is reasonably converged to a position relatively close to the second lens. In addition, the inner diameter of the first spacer element is close to the edge of the effective diameter of the second lens, effectively blocking the stray light at the edge of the effective diameter of the second lens and improving the imaging quality of the optical lens.

[0062] In this embodiment, the spacer element group at least includes a second spacer element located between the second lens and the third lens and at least partially contacting the image-side surface of the second lens. The inner diameter d2s of the object-side surface of the second spacer element, the inner diameter d2m of the image-side surface of the second spacer element, and the air gap T23 between the second lens and the third lens along the optical axis of the optical lens satisfy: 2.65 < |d2s - d2m| / T23 < 28.00. If the value of |d2s - d2m| / T23 is too large, it means that the difference in the inner diameters of the object-side surface and the image-side surface of the second spacer element is too large relative to the air gap between the second lens and the third lens along the optical axis, resulting in an excessive tilt angle of the inner ring surface of the second spacer element relative to the optical axis, thus failing to effectively block the stray light. If the value of |d2s - d2m| / T23 is too small, the tilt angle of the second spacer element is too small, and the risk of the inner ring surface of the second spacer element reflecting the stray light is high. At the same time, it is not conducive to the assembly stability between the second lens and the third lens. By restricting |d2s - d2m| / T23 within a reasonable range, the tilt angle of the inner ring surface of the second spacer element relative to the optical axis can be controlled, preventing the stray light from reflecting at the inner ring surface of the second spacer element, effectively blocking the stray light, improving the imaging quality of the optical lens, and maintaining good assembly stability between the second lens and the third lens.

[0063] In this embodiment, the spacer element group at least includes a second spacer element located between the second lens and the third lens and at least partially contacting the image side surface of the second lens. The maximum thickness CP2 of the second spacer element in the direction of the optical axis of the optical lens and the air gap T23 between the second lens and the third lens in the direction of the optical axis satisfy: 12.25 < CP2 / T23 < 13.80. If the value of CP2 / T23 is too large, the maximum thickness of the second spacer element in the direction of the optical axis is too large relative to the air gap between the second lens and the third lens in the direction of the optical axis. There is a high risk that the second lens and the third lens cannot be assembled stably, and it is not conducive to controlling the edge thickness ratio of the second lens and the third lens, resulting in an increase in production cost and a reduction in the overall stability and optical performance of the optical lens. If the value of CP2 / T23 is too small, it will affect the ability of the second spacer element to block stray light and the assembly stability of the front lens of the optical lens. By controlling CP2 / T23 within a reasonable range, the appropriate thickness of the second spacer element can be maintained, which can not only meet cost control but also ensure the assembly stability of the optical lens and the ability to block stray light, improving the yield and optical performance.

[0064] In this embodiment, the spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The maximum thickness of the third spacer element in the direction of the optical axis of the optical lens is the smallest among the maximum thicknesses of all spacer elements in the spacer element group in the direction of the optical axis. The effective focal length f3 of the third lens, the effective focal length f4 of the fourth lens, and the inner diameter d3s of the object side surface of the third spacer element satisfy: -1.80 < (f3 - f4) / d3s < -1.00. If the value of (f- f4) / d3s is too large or too small, it will cause the off-axis aberration of the optical lens not to be properly balanced, reducing the image quality of the optical lens. By controlling (f3 - f4) / d3s within a reasonable range, the off-axis aberration can be effectively balanced by controlling the image side inner diameter of the third spacer element and the refractive power of the third lens and the fourth lens, improving the imaging quality of the optical lens.

[0065] In this embodiment, the axial distance TD between the object-side surface of the first lens and the image-side surface of the fourth lens is greater than the distance L between the object-side end face of the lens barrel and the image-side end face of the lens barrel along the optical axis. The center thickness CT1 of the first lens along the optical axis and the distance EP01 between the object-side end face of the lens barrel and the object-side surface of the first spacer element along the optical axis satisfy the condition: 0.20 ≤ CT1 / EP01 < 0.40. Since the optical lens is a wide-angle design and has a large sagitta, to prevent the object-side end face of the lens barrel from blocking light and affecting the external field of view imaging of the optical lens, the axial distance between the object-side surface of the first lens and the image-side surface of the fourth lens is controlled to be greater than the distance between the object-side end face of the lens barrel and the image-side end face of the lens barrel along the optical axis. Under the structural condition that TD > L, the shape of the first lens needs to be strictly controlled. By controlling CT1 / EP01 within a reasonable range, the excessive lens edge thickness ratio caused by the small center thickness of the first lens along the optical axis is effectively prevented from affecting the formation of the first lens. This not only improves the formation of the first lens, but also improves the length of the structural parts of the first lens and the uniformity of the stress distribution of the first lens, thereby ensuring the assembly stability of the first lens.

[0066] In this embodiment, the spacer element group includes at least a second spacer element located between the second lens and the third lens and in at least partial contact with the image-side surface of the second lens. The outer diameter D2m of the image-side surface of the second spacer element, the inner diameter d2s of the object-side surface of the second spacer element, and the effective radius DT22 of the image-side surface of the second lens satisfy the following condition: 1.50 < (D2m - d2s) / (2 × DT22) < 2.80. If the value of (D2m - d2s) / (2 × DT22) is too large, the annular width of the second spacer element will be too large relative to the effective radius of the second lens, which is detrimental to the assembly stability of the second lens. If the value of (D2m - d2s) / (2 × DT22) is too small, it will not only affect the ability of the optical lens to block stray light in the middle, but also be detrimental to the assembly stability of the second and third lenses. By controlling (D2m-d2s) / (2×DT22) within a reasonable range, the relationship between the ring width of the second spacer element and the effective radius of the second lens can be constrained. This not only ensures the ability of the optical lens to block stray light in the middle, but also improves the stability of the assembly of the second and third lenses, thereby increasing the yield and productivity of the optical lens.

[0067] In this embodiment, the spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The air gap T34 between the third lens and the fourth lens along the optical axis of the optical lens and the maximum thickness CP3 of the third spacer element along the optical axis satisfy: 6.95 < T34 / CP3 < 8.60. If the value of T34 / CP3 is too large, the maximum thickness of the third spacer element along the optical axis is too small relative to the air gap between the third lens and the fourth lens along the optical axis, which is not conducive to the stability of the assembly of the optical lens. If the value of T34 / CP3 is too small, the maximum thickness of the third spacer element along the optical axis is too large relative to the air gap between the third lens and the fourth lens along the optical axis, increasing the manufacturing cost and affecting the light shielding effect at the same time. By controlling T34 / CP3 within a reasonable range, the thickness of the third spacer element can be kept appropriate, ensuring the assembly stability of the third lens and the fourth lens, and ensuring the assembly stability and cost efficiency of the optical lens, while effectively blocking stray light.

[0068] In this embodiment, the spacer element group at least includes a second spacer element located between the second lens and the third lens and at least partially contacting the image side surface of the second lens, and a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The distance EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element along the optical axis of the optical lens and the effective focal length f3 of the third lens satisfy: -0.65 < EP23 / f3 < -0.30. If the value of EP23 / f3 is too large, the thickness of a part of the structure of the second lens is small, and the air gap between the second lens and the third lens on the optical axis is small, which is not conducive to the beam propagation in the middle of the optical lens, and causes an unreasonable fit between the image side end surface of the lens barrel and the lens group, resulting in a large misalignment of the assembly bearing surface and affecting the optical performance and assembly stability of the optical lens. If the value of EP23 / f3 is too small, the air gap between the second lens and the third lens on the optical axis is large, affecting the compactness of the lens group and the optical performance of the optical lens. Especially during assembly, it is difficult to adjust the positions of the second lens and the third lens, which is not conducive to the assembly stability. By controlling EP23 / f3 within a reasonable range, the air gap between the second lens and the third lens on the optical axis can be effectively controlled, so that not only the structure of the lens group can be made more compact, but also a reasonable fit between the image side end surface of the lens barrel and the lens group can be achieved, avoiding a large misalignment of the assembly bearing surface, and thus contributing to improving the assembly stability of the lens group.

[0069] In this embodiment, the spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The effective radius DT32 of the image side surface of the third lens and the effective radius DT41 of the object side surface of the fourth lens satisfy: 0.90 < DT32 / DT41 < 1.00; the inner diameter d3m of the image side surface of the third spacer element and the effective radius DT41 of the object side surface of the fourth lens satisfy: 2.00 < d3m / DT41 < 2.50. By controlling DT32 / DT41 within a reasonable range, the effective radius sizes of the image side surface of the third lens and the object side surface of the fourth lens are relatively close, ensuring the dimensional uniformity at the rear end of the lens barrel and the assembly stability of the optical lens. However, at the same time, the stray light passing through the image side surface of the third lens will also pass through the fourth lens, affecting the imaging quality. Therefore, by controlling d3m / DT41 within a reasonable range and controlling the inner diameter of the image side surface of the third spacer element and the effective radius size of the object side surface of the fourth lens, it helps to block the stray light at this location and also helps to balance the off-axis aberration, improving the imaging quality of the optical lens.

[0070] In this embodiment, the spacer element group at least includes a second spacer element located between the second lens and the third lens and at least partially contacting the image side surface of the second lens. The curvature radius R4 of the image side surface of the second lens and the inner diameter d2s of the object side surface of the second spacer element satisfy: -0.40 < R4 / d2s < -0.25; the maximum thickness CP2 of the second spacer element in the direction of the optical axis of the optical lens and the sagittal height SAG22 of the image side surface of the second lens satisfy: -1.05 < CP2 / SAG22 < -0.85. By controlling R4 / d2s within a reasonable range, the curvature radius of the image side surface of the second lens and the inner diameter of the object side surface of the second spacer element can be restricted, and the inner diameter of the object side surface of the second spacer element can be reasonably controlled to prevent the stray light from the second lens from passing through the inner diameter edge of the second spacer element to form stray light, resulting in a decrease in imaging quality. However, at the same time, an excessively large curvature radius of the image side surface of the second lens will cause an excessively large sagittal height of the image side surface of the second lens, affecting the assembly stability of the front-end lens. By controlling CP2 / SAG22 within a reasonable range, the maximum thickness of the second spacer element in the direction of the optical axis and the size of the sagittal height of the image side surface of the second lens can be controlled, further restricting the sagittal height of the second lens within a reasonable range and avoiding the situation of unstable assembly of the second lens.

[0071] In this embodiment, the spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The inner diameter d3s of the object side surface of the third spacer element and the inner diameter d0m of the image side end surface of the lens barrel satisfy: 0.40 < d3s / d0m < 1.00. When the value of d3s / d0m is too large, the inner diameter of the object side surface of the third spacer element is too large relative to the inner diameter of the image side end surface of the lens barrel, resulting in non-imaging light entering the fourth lens from the image side surface of the third lens, ultimately forming stray light and affecting the imaging quality. When the value of d3s / d0m is too small, the inner diameter of the object side surface of the third spacer element is too small, and the third spacer element will bend after the optical lens is baked, affecting the appearance. At the same time, it cannot effectively block stray light, and the imaging quality decreases. By controlling d3s / d0m within a reasonable range, it can ensure that the inner diameter of the third spacer element is appropriate, avoiding the generation of stray light and preventing the third spacer element from bending after baking, thus ensuring the light shielding function of the third spacer element while ensuring the stability of the imaging quality and appearance.

[0072] In this embodiment, the spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f4 of the fourth lens satisfy: -0.65 < R8 / f4 ≤ -0.55; the distance EP30 from the image side surface of the third spacer element to the image side end surface of the lens barrel along the optical axis direction of the optical lens and the sagitta SAG42 of the image side surface of the fourth lens satisfy: -3.75 < EP30 / SAG42 < -1.55. By controlling R8 / f4 within a reasonable range, the risk of stray light can be reduced to a certain extent, the overall performance of the optical lens can be improved, and the risk during the manufacturing process can be reduced. However, at the same time, under the structural conditions that satisfy R8 / f4, the sagitta of the image side surface of the fourth lens is too large, and the fourth lens is unstable during the assembly process, affecting the assembly quality of the optical lens. By controlling EP30 / SAG42 within a reasonable range, it can ensure that the radius of curvature of the image side surface of the fourth lens is appropriate, avoiding difficulties in forming the fourth lens. At the same time, reasonably restricting EP30 / SAG42 can ensure that the sagitta of the fourth lens is moderate, not only ensuring the forming yield rate of the fourth lens but also ensuring the correct fit between the fourth lens and the lens barrel, ensuring the light shielding effect at the end of the optical lens, and thus improving the imaging quality and assembly stability of the optical lens.

[0073] In this embodiment, the spacer element group at least includes a second spacer element located between the second lens and the third lens and at least partially contacting the image side surface of the second lens, and a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The Abbe number of the third lens is less than half of the Abbe numbers of the other lenses in the lens group. The center thickness CT3 of the third lens along the optical axis of the optical lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 0.40 < CT3 / R6 < 0.55. The inner diameter d3s of the object side surface of the third spacer element and the inner diameter d2m of the image side surface of the second spacer element satisfy: 0.85 < d3s / d2m < 1.40.

[0074] By matching the materials of each lens and controlling the ratio of the center thickness of the third lens along the optical axis to the radius of curvature of the image side surface of the third lens, the dispersion characteristic matching degree between the third lens and other lenses can be ensured, and the edge thickness ratio of the third lens can be restricted, reducing the molding difficulty. However, if the inner diameter of the third spacer element that abuts against the third lens is too small, a long cantilever structure will be formed, and even bending may occur during the subsequent baking process, resulting in the third spacer element being unable to block stray light, causing a decline in imaging quality. Therefore, by controlling d3s / d2m within a reasonable range and restricting the inner diameter ratio of the object side surface of the third spacer element to the image side surface of the second spacer element, non-imaging light can be effectively blocked, avoiding the stray light problem caused by the above reasons.

[0075] In this embodiment, the spacer element group at least includes a second spacer element located between the second lens and the third lens and at least partially contacting the image side surface of the second lens. The following relationships are satisfied between the radius of curvature R2 of the image side surface of the first lens and the air gap T12 between the first lens and the second lens along the optical axis of the optical lens: 0.30 < R2 / T12 < 0.65; the following relationship is satisfied between the axial distance TD from the object side surface of the first lens to the image side surface of the fourth lens and the maximum thickness CP2 of the second spacer element along the optical axis: 9.50 < TD / CP2 < 10.75. By controlling R2 / T12 within a reasonable range, it helps to maintain a reasonable air gap between the first lens and the second lens, which can not only ensure the accurate convergence of light rays but also ensure the assembly stability of the lens group. However, the radius of curvature of the image side surface of the first lens and the air gap between the first lens and the second lens along the optical axis are relatively large, resulting in poor stability at the front end of the lens group. Especially when subjected to external pressure or vibration, the first lens and the second lens may be displaced, affecting the imaging quality. By controlling TD / CP2 within a reasonable range, the proportional relationship between the axial distance from the object side surface of the first lens to the image side surface of the fourth lens and the maximum thickness of the second spacer element along the optical axis can be restricted, which can ensure that the position of the second spacer element in the lens group is stable enough, reduce the position offset caused by external forces, and further ensure the assembly stability of the first lens and the second lens, improving the assembly stability and reliability of the optical lens.

[0076] It should be noted that the sagittal height SAG22 of the image side surface of the second lens refers to the axial displacement between the intersection point of the image side surface of the second lens and the optical axis and the vertex of the effective radius of the image side surface of the second lens. Similarly, the sagittal height SAG42 of the image side surface of the fourth lens refers to the axial displacement between the intersection point of the image side surface of the fourth lens and the optical axis and the vertex of the effective radius of the image side surface of the fourth lens.

[0077] Second Embodiment

[0078] As Figures 1 to 19As shown, the number of lenses with optical power in the optical lens is four. The optical lens includes a lens group, a spacer element group, and a lens barrel. From the object side to the image side of the optical lens, the lens group includes a first lens to a fourth lens arranged at intervals in sequence; the first lens has a negative optical power, the paraxial region of the object side surface of the first lens is convex, and the image side surface of the first lens is concave; the second lens has a positive optical power, the paraxial region of the object side surface of the second lens is convex, and the image side surface of the second lens is convex; the third lens has a negative optical power, the paraxial region of the image side surface of the third lens is concave; the fourth lens has a positive optical power, the paraxial region of the object side surface of the fourth lens is convex, and the image side surface of the fourth lens is convex. The outer diameter of the first lens is greater than the outer diameter of the fourth lens; the spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens; the lens group and the spacer element group are accommodated in the lens barrel, and the inner diameter of the object side end surface of the lens barrel is greater than the inner diameter of the image side end surface of the lens barrel; wherein, the effective radius DT32 of the image side surface of the third lens and the effective radius DT41 of the object side surface of the fourth lens satisfy: 0.90 < DT32 / DT41 < 1.00; the inner diameter d3m of the image side surface of the third spacer element and the effective radius DT41 of the object side surface of the fourth lens satisfy: 2.00 < d3m / DT41 < 2.50.

[0079] The optical lens of the present application uses four lenses with optical power. The first lens to the fourth lens are arranged in sequence at intervals. Among them, the outer diameter of the first lens is greater than the outer diameter of the fourth lens, and the inner diameter of the object side end surface of the lens barrel is greater than the inner diameter of the image side end surface of the lens barrel. In the optical lens of the present application, the ratio of the effective radius of the image side surface of the third lens to the effective radius of the object side surface of the fourth lens is within a reasonable range, which can ensure the dimensional uniformity at the rear end of the lens barrel and guarantee the assembly stability of the optical lens. However, the effective radius sizes of the image side surface of the third lens and the object side surface of the fourth lens are relatively close, resulting in the stray light passing through the image side surface of the third lens also passing through the fourth lens, affecting the imaging quality. By controlling d3m / DT41 within a reasonable range and restricting the ratio of the inner diameter of the image side surface of the third spacer element to the effective radius of the object side surface of the fourth lens, the stray light between the third lens and the fourth lens can be effectively blocked, which helps to balance the off-axis aberration and improve the imaging quality of the optical lens.

[0080] Table 2 below and Figures 26 to 31 shows the stray light distribution at the third lens when the value of d3m / DT41 is different under the condition of DT32 / DT41 = 0.96 for the optical lenses of Example 1 and Comparative Example 3 and Comparative Example 4 of the present application. Among them, the stray light optical path and the stray light energy intensity distribution diagram show the stray light optical path and its corresponding energy distribution peak position on the imaging surface.

[0081] Table 2

[0082]

[0083] When the optical lens of Comparative Example 3 satisfies DT32 / DT41=0.93 and d3m / DT41=3.5, the stray light path and energy intensity are as follows: Figures 28 to 29 As shown, when d3m / DT41 is too large, the inner diameter of the image-side surface of the third spacer element becomes smaller. This not only affects the rearward transmission of imaging light but also increases new internal reflection stray light, resulting in stronger stray light energy on the imaging surface. For the optical lens in Comparative Example 4, when DT32 / DT41 = 0.93 and d3m / DT41 = 1.0, the stray light path and energy intensity are as follows: Figures 30 to 31 As shown, when the value of d3m / DT41 is too small, the inner diameter of the image side of the third spacer element becomes larger, and too much non-imaging light is transmitted to the rear through the third spacer element, resulting in strong stray light energy on the imaging surface.

[0084] In Embodiment 1 of this application, when DT32 / DT41=0.93 and d3m / DT41=2.05, the stray light path and energy intensity are as follows: Figure 26 and Figure 27 As shown, the inner diameter of the image side of the third spacer element of the optical lens is reasonable, thus effectively blocking stray light between the third and fourth lenses, resulting in weak stray light energy on the imaging surface.

[0085] It should be noted that this embodiment also includes other conditional expressions from the above embodiments, which will not be elaborated here.

[0086] Optionally, the aforementioned optical lens may also include protective glass for protecting the photosensitive element located on the imaging plane.

[0087] The optical lens in this application may employ multiple lenses, such as the four lenses described above. In this application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. An aspherical lens is characterized by a continuously changing curvature from the lens center to the lens periphery. Unlike a spherical lens, which has a constant curvature from the lens center to the lens periphery, an aspherical lens has superior curvature radius characteristics, offering advantages in improving distortion aberrations and astigmatism. By using an aspherical lens, aberrations occurring during imaging can be eliminated as much as possible, thereby improving image quality.

[0088] However, those skilled in the art will understand that the number of lenses constituting the optical lens can be varied to obtain the various results and advantages described herein without departing from the technical solutions claimed in this application. For example, although four lenses have been described as an example in the embodiments, the optical lens is not limited to including four lenses. If necessary, the optical lens may also include other numbers of lenses.

[0089] Figure 1 and Figure 32A schematic diagram showing the dimensions of an optical lens according to this application is provided. Figure 1 The parameters d1s, d3m, EP01, etc., are indicated to provide a clear and intuitive understanding of their meaning. To facilitate the description of the optical lens and the specific lens shape, these parameters will not be shown in the accompanying drawings when describing specific embodiments.

[0090] The following description, with reference to the accompanying drawings, further illustrates examples of specific surface shapes and parameters of optical lenses applicable to the above embodiments.

[0091] It should be noted that any one of the examples in Embodiments 1 to 9 described below is applicable to all embodiments of this application.

[0092] Example 1

[0093] like Figure 2 As shown, an optical lens according to Embodiment 1 of this application is described. Figure 2 A schematic diagram of the optical lens of Embodiment 1 is shown.

[0094] like Figure 2 As shown, the optical lens, from the object side to the image side, includes, in sequence: lens barrel P0, first lens E1, first spacer element P1, first auxiliary spacer element P1b, second lens E2, second spacer element P2, third lens E3, third spacer element P3, and fourth lens E4. The first auxiliary spacer element is located between the first spacer element and the second lens and is at least partially in contact with the image side of the first spacer element.

[0095] In this embodiment, the first lens E1 has negative optical power, its object-side surface S1 is convex, and its image-side surface S2 is concave. The second lens E2 has positive optical power, its object-side surface S3 is convex, and its image-side surface S4 is convex. The third lens E3 has negative optical power, its object-side surface S5 is concave, and its image-side surface S6 is concave. The fourth lens E4 has positive optical power, its object-side surface S7 is convex, and its image-side surface S8 is convex.

[0096] Table 3 shows the basic structural parameters of the optical lens in Embodiment 1, where the units for radius of curvature, thickness / distance, effective radius, and focal length are all millimeters (mm).

[0097] Table 3

[0098]

[0099] In Embodiment 1, the object-side surface and image-side surface of any one of the first lens E1 to the fourth lens E4 are aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0100] Formula (1);

[0101] Where x is the distance vector from the vertex of the aspherical surface along the optical axis at a height of h; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 3 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 4 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 that can be used for each aspherical mirror S1-S8 in Example 1.

[0102] Table 4 shows the higher-order coefficients that can be used for each aspherical mirror in the embodiments, wherein the surface shape of each aspherical surface can be defined by formula (1) given in Embodiment 1 above. In this embodiment, the object-side surface and image-side surface of the first to fourth lenses are both aspherical.

[0103] Table 4

[0104]

[0105] Figure 5 The on-axis chromatic aberration curve of the optical lens of Embodiment 1 is shown, which indicates the deflection of the focal point of light of different wavelengths after passing through the optical lens. Figure 6 The astigmatism curve of the optical lens of Embodiment 1 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 7 The distortion curve of the optical lens of Embodiment 1 is shown, which represents the distortion magnitude value corresponding to different field of view angles.

[0106] according to Figures 5 to 7 As can be seen, the optical lens given in Example 1 can achieve good imaging quality.

[0107] Example 2

[0108] like Figure 3 As shown, an optical lens according to Embodiment 2 of this application is described. The difference between it and Embodiment 1 is that the distance and thickness between the various spacer elements, lenses, lens barrels P0, etc. are different.

[0109] Figure 3 A schematic diagram of the optical lens structure of Embodiment 2 is shown. For simplicity, descriptions similar to those in Embodiment 1 are omitted. In this embodiment, the maximum thickness of the first spacer element along the optical axis is increased, providing sufficient air gap for the first and second lenses, ensuring that light rays converge reasonably to a position closer to the second lens. Furthermore, the inner diameter of the object-side surface of the second spacer element is reduced, effectively blocking stray light rays from the edges of the third lens, thus significantly improving the imaging quality of the optical lens.

[0110] Example 3

[0111] like Figure 4 As shown, an optical lens according to Embodiment 3 of this application is described. The difference between this lens and Embodiment 1 is that the distances and thicknesses between the various spacer elements, lenses, lens barrels, etc., are different.

[0112] Figure 4 A schematic diagram of the optical lens structure of Embodiment 3 is shown. For simplicity, descriptions similar to those in Embodiment 1 are omitted. In this embodiment, the inner wall of the lens barrel has a support portion extending towards the optical axis, which is in close contact with the image side of the first lens. A first spacer element is disposed between the lens barrel support portion and the second lens. The first lens is assembled from the object side, and the second to fourth lenses are assembled sequentially from the image side. The image side of the first lens rests on the support portion, reducing the difficulty of assembling the front end of the optical lens and the risk of stress concentration.

[0113] Example 4

[0114] like Figure 8 As shown, an optical lens according to Embodiment 4 of this application is described. Figure 8 A schematic diagram of the optical lens of Embodiment 4 is shown.

[0115] like Figure 8 As shown, the optical lens, from the object side to the image side, includes, in sequence: lens barrel P0, first lens E1, first spacer element P1, second lens E2, second spacer element P2, third lens E3, third spacer element P3, and fourth lens E4. In this embodiment, the first lens E1 has negative optical power, its object side S1 is convex, and its image side S2 is concave. The second lens E2 has positive optical power, its object side S3 is convex, and its image side S4 is convex. The third lens E3 has negative optical power, its object side S5 is convex, and its image side S6 is concave. The fourth lens E4 has positive optical power, its object side S7 is convex, and its image side S8 is convex.

[0116] Table 5 shows the basic structural parameters of the optical lens in Embodiment 4, where the units for radius of curvature, thickness / distance, effective radius, and focal length are all millimeters (mm).

[0117] Table 5

[0118]

[0119] Table 6 shows the higher-order coefficients that can be used for each aspherical mirror in the embodiments, wherein the surface shape of each aspherical surface can be defined by formula (1) given in Embodiment 1 above. In this embodiment, the object-side surface and image-side surface of the first to fourth lenses are both aspherical.

[0120] Table 6

[0121]

[0122] Figure 11 The on-axis chromatic aberration curve of the optical lens of Embodiment 4 is shown, which indicates the deflection of the focal point of light of different wavelengths after passing through the optical lens. Figure 12 The astigmatism curves of the optical lens of Embodiment 4 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 13 The distortion curve of the optical lens in Embodiment 4 is shown, which represents the distortion magnitude value corresponding to different field of view angles.

[0123] according to Figures 11 to 13 It can be seen that the optical lens given in Example 4 can achieve good imaging quality.

[0124] Example 5

[0125] like Figure 9 The image illustrates an optical lens according to Embodiment 5 of this application. The difference between Embodiment 4 and Embodiment 5 lies in the distances and thicknesses between the spacer elements, lenses, and lens barrel P0. Specifically, the first auxiliary spacer element is located between the first spacer element and the second lens and is at least partially in contact with the image-side surface of the first spacer element.

[0126] Figure 9 A schematic diagram of the optical lens structure of Embodiment 5 is shown. For simplicity, descriptions similar to those in Embodiment 4 are omitted. In this embodiment, the maximum thickness of the first spacer element along the optical axis is increased, providing sufficient air gap for the first and second lenses, ensuring that light rays converge reasonably to a position closer to the second lens. The corresponding thinning of the first lens structure facilitates a more reasonable weight distribution at the front end of the optical lens. Simultaneously, the first auxiliary spacer element effectively blocks non-imaging light rays from entering the second lens. Furthermore, the image-side of the third lens engages with the object-side of the fourth lens, improving the assembly stability of the rear lenses of the optical lens.

[0127] Example 6

[0128] like Figure 10 The image illustrates an optical lens according to Embodiment Six of this application. The difference between Embodiment Six and Embodiment Four lies in the distances and thicknesses between the various spacer elements, lenses, and lens barrel P0. Specifically, the first auxiliary spacer element is located between the first spacer element and the second lens and is at least partially in contact with the image-side surface of the first spacer element. The first additional spacer element is located between the first auxiliary spacer element and the second lens and is at least partially in contact with the image-side surface of the first auxiliary spacer element.

[0129] Figure 10A schematic diagram of the optical lens structure of Embodiment Six is ​​shown. For simplicity, descriptions similar to those in Embodiment Four are omitted. In this embodiment, a first spacer element, a first auxiliary spacer element, and a first additional spacer element are sequentially included between the first lens and the second lens. The image-side surface of the first lens is stably engaged with the object-side surface of the first auxiliary spacer element. The first spacer element is located within the inner ring of the engagement position between the image-side surface of the first lens and the object-side surface of the first auxiliary spacer element to improve the stability of the lens-spacer element connection. The inner diameter of the first additional spacer element blocks non-imaging light rays from entering the second lens. Furthermore, the image-side surface of the third lens is engaged with the object-side surface of the fourth lens, which is beneficial to the stability of the lens assembly at the rear end of the optical lens.

[0130] Example 7

[0131] like Figure 14 As shown, an optical lens according to Embodiment Seven of this application is described. Figure 14 A schematic diagram of the optical lens of Embodiment Seven is shown.

[0132] like Figure 14 As shown, the optical lens, from the object side to the image side, includes, in sequence: lens barrel P0, first lens E1, first spacer element P1, first auxiliary spacer element P1b, second lens E2, second spacer element P2, third lens E3, third spacer element P3, and fourth lens E4. The first auxiliary spacer element is located between the first spacer element and the second lens and is at least partially in contact with the image side of the first spacer element.

[0133] In this embodiment, the first lens E1 has negative optical power, its object-side surface S1 is convex, and its image-side surface S2 is concave. The second lens E2 has positive optical power, its object-side surface S3 is convex, and its image-side surface S4 is convex. The third lens E3 has negative optical power, its object-side surface S5 is concave, and its image-side surface S6 is concave. The fourth lens E4 has positive optical power, its object-side surface S7 is convex, and its image-side surface S8 is convex.

[0134] Table 7 shows the basic structural parameters of the optical lens of Embodiment 7, wherein the units of radius of curvature, thickness / distance, effective radius and focal length are all millimeters (mm).

[0135] Table 7

[0136]

[0137] Table 8 shows the higher-order coefficients that can be used for each aspherical mirror in the embodiments, wherein the surface shape of each aspherical surface can be defined by formula (1) given in Embodiment 1 above. In this embodiment, the object-side surface and image-side surface of the first to fourth lenses are both aspherical.

[0138] Table 8

[0139]

[0140] Figure 17 The on-axis chromatic aberration curve of the optical lens of Embodiment 7 is shown, which indicates the deflection of the focal point of light of different wavelengths after passing through the optical lens. Figure 18 The astigmatism curve of the optical lens of Embodiment 7 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 19 The distortion curve of the optical lens of Embodiment 7 is shown, which represents the distortion magnitude value corresponding to different field of view angles.

[0141] according to Figures 17 to 19 It can be seen that the optical lens given in Example 7 can achieve good imaging quality.

[0142] Example 8

[0143] like Figure 15 As shown, an optical lens of Embodiment 8 of this application is described. The difference between Embodiment 7 and Embodiment 8 is that the distance and thickness between the various spacer elements, lenses, lens barrels, etc. are different.

[0144] Figure 15 A schematic diagram of the optical lens structure of Embodiment 5 is shown. For the sake of brevity, descriptions similar to those in Embodiment 4 are omitted. In this embodiment, the first auxiliary spacer element is removed, and the inner diameter of the first spacer element is reduced, effectively blocking non-imaging light rays from entering the second lens.

[0145] Example 9

[0146] like Figure 16 As shown, an optical lens of Embodiment Nine of this application is described. The difference between Embodiment Seven and Embodiment Nine is that the distance and thickness between the various spacer elements, lenses, lens barrels, etc. are different.

[0147] Figure 16 A schematic diagram of the optical lens structure of Embodiment Nine is shown. For simplicity, descriptions similar to those in Embodiment Seven are omitted. In this embodiment, the first auxiliary spacer element is removed, and the inner diameter of the first spacer element is reduced, effectively blocking non-imaging light from entering the second lens. Furthermore, the wall thickness at the rear end of the lens barrel is increased, which helps protect the structural stability of the small-sized lens at the rear end of the optical lens.

[0148] In summary, embodiments one through nine of the optical lens satisfy the relationships shown in Table 9.

[0149] Table 9

[0150]

[0151] Table 10 shows the effective focal length and some structural parameters of each lens of the optical lenses in Examples 1 to 9, in mm. The F-number of the optical lens is represented by Fno; the maximum field of view (FOV) of the optical lens is in °.

[0152] Table 10

[0153]

[0154] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0155] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0156] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0157] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An optical lens, characterized in that, The optical lens has four lenses with optical power, and the optical lens includes: The lens group, from the object side to the image side of the optical lens, includes a first lens to a fourth lens arranged at intervals in sequence; The first lens has negative optical power, the paraxial region of its object-side surface is convex, and the image-side surface is concave; the second lens has positive optical power, the paraxial region of its object-side surface is convex, and the image-side surface is convex; the third lens has negative optical power, the paraxial region of its image-side surface is concave; the fourth lens has positive optical power, the paraxial region of its object-side surface is convex, and the image-side surface is convex, and the outer diameter of the first lens is larger than the outer diameter of the fourth lens; A group of spacers, the group of spacers including at least a first spacer located between the first lens and the second lens and closest to the image side of the first lens, and a second spacer located between the second lens and the third lens and at least partially in contact with the image side of the second lens; The lens barrel, the lens group and the spacer element group are housed within the lens barrel, and the inner diameter of the object-side end face of the lens barrel is larger than the inner diameter of the image-side end face of the lens barrel. The inner diameter d0s of the object-side end face of the lens barrel, the inner diameter d0m of the image-side end face of the lens barrel, and the axial distance TD from the object-side surface of the first lens to the image-side surface of the fourth lens satisfy the following condition: 0.40 < (d0s - d0m) / TD < 1.

10. The inner diameter d0s of the object-side end face of the lens barrel, the inner diameter d1s of the object-side surface of the first spacer element, and the radius of curvature R2 of the image-side surface of the first lens satisfy the following condition: 4.20 < (d0s - d1s) / R2 < 8.

95. The inner diameter d2s of the object side of the second spacer element, the inner diameter d2m of the image side of the second spacer element, and the air gap T23 between the second lens and the third lens along the optical axis of the optical lens satisfy the following condition: 2.65 < |d2s - d2m| / T23 < 28.

00.

2. The optical lens according to claim 1, characterized in that, The air gap between the first lens and the second lens along the optical axis of the optical lens is greater than the air gap between any two adjacent lenses in the lens group along the optical axis. The distance EP01 from the object-side end face of the lens barrel to the object-side surface of the first spacer element along the optical axis, and the air gap T12 between the first lens and the second lens along the optical axis satisfy the following condition: 0.

50. <EP01 / T12<0.95。 3. The optical lens according to claim 1, characterized in that, The maximum thickness CP2 of the second spacer element along the optical axis of the optical lens and the air gap T23 between the second lens and the third lens along the optical axis satisfy: 12.25 <CP2 / T23<13.80。 4. The optical lens according to claim 1, characterized in that, The at least one spacer element group includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The maximum thickness of the third spacer element in the direction of the optical axis of the optical lens is the smallest among the maximum thicknesses of all spacer elements in the spacer element group in the direction of the optical axis. The effective focal length f3 of the third lens, the effective focal length f4 of the fourth lens, and the inner diameter d3s of the object side surface of the third spacer element satisfy: -1.80 < (f3 - f4) / d3s < -1.

00.

5. The optical lens according to claim 1, characterized in that, The on-axis distance TD from the object side surface of the first lens to the image side surface of the fourth lens is greater than the distance L in the direction of the optical axis of the optical lens from the object side end surface of the lens barrel to the image side end surface of the lens barrel; the central thickness CT1 of the first lens in the direction of the optical axis and the distance EP01 from the object side end surface of the lens barrel to the object side surface of the first spacer element in the direction of the optical axis satisfy: 0.20 ≤ CT1 / EP01 < 0.

40.

6. The optical lens according to claim 1, characterized in that, The outer diameter D2m of the image side surface of the second spacer element, the inner diameter d2s of the object side surface of the second spacer element, and the effective radius DT22 of the image side surface of the second lens satisfy: 1.50 < (D2m - d2s) / (2 × DT22) < 2.

80.

7. The optical lens according to claim 1, characterized in that, The at least one spacer element group includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The air gap T34 between the third lens and the fourth lens in the direction of the optical axis of the optical lens and the maximum thickness CP3 of the third spacer element in the direction of the optical axis satisfy: 6.95 < T34 / CP3 < 8.

60.

8. The optical lens according to claim 1, characterized in that, A third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The distance EP23 from the image side surface of the second spacer element to the object side surface of the third spacer element in the direction of the optical axis of the optical lens and the effective focal length f3 of the third lens satisfy: -0.65 < EP23 / f3 < -0.

30.

9. The optical lens according to claim 1, characterized in that, The at least one spacer element group includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The effective radius DT32 of the image side surface of the third lens and the effective radius DT41 of the object side surface of the fourth lens satisfy: 0.90 < DT32 / DT41 < 1.00; the inner diameter d3m of the image side surface of the third spacer element and the effective radius DT41 of the object side surface of the fourth lens satisfy: 2.00 < d3m / DT41 < 2.

50.

10. The optical lens according to claim 1, characterized in that, The following relationships are satisfied between the radius of curvature R4 of the image side surface of the second lens and the inner diameter d2s of the object side surface of the second spacer element: -0.40 < R4 / d2s < -0.25; The following relationships are satisfied between the maximum thickness CP2 of the second spacer element in the direction of the optical axis of the optical lens and the sag SAG22 of the image side surface of the second lens: -1.05 < CP2 / SAG22 < -0.

85.

11. The optical lens according to claim 1, characterized in that, The spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The following relationship is satisfied between the inner diameter d3s of the object side surface of the third spacer element and the inner diameter d0m of the image side end surface of the lens barrel: 0.40 < d3s / d0m < 1.

00.

12. The optical lens according to claim 1, characterized in that, The spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The following relationship is satisfied between the radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f4 of the fourth lens: -0.65 < R8 / f4 ≤ -0.55; The following relationship is satisfied between the distance EP30 from the image side surface of the third spacer element to the image side end surface of the lens barrel in the direction of the optical axis of the optical lens and the sag SAG42 of the image side surface of the fourth lens: -3.75 < EP30 / SAG42 < -1.

55.

13. The optical lens according to claim 1, characterized in that, The spacer element group at least includes a third spacer element located between the third lens and the fourth lens and at least partially contacting the image side surface of the third lens. The Abbe number of the third lens is less than half of the Abbe numbers of the other lenses in the lens group; The following relationship is satisfied between the central thickness CT3 of the third lens in the direction of the optical axis of the optical lens and the radius of curvature R6 of the image side surface of the third lens: 0.40 < CT3 / R6 < 0.55; The following relationship is satisfied between the inner diameter d3s of the object side surface of the third spacer element and the inner diameter d2m of the image side surface of the second spacer element: 0.85 < d3s / d2m < 1.

40.

14. The optical lens according to claim 1, characterized in that, The following relationship is satisfied between the radius of curvature R2 of the image side surface of the first lens and the air gap T12 between the first lens and the second lens in the direction of the optical axis of the optical lens: 0.30 < R2 / T12 < 0.65; The following relationship is satisfied between the on-axis distance TD from the object side surface of the first lens to the image side surface of the fourth lens and the maximum thickness CP2 of the second spacer element in the direction of the optical axis: 9.50 < TD / CP2 < 10.75.

Images