Optical lens

Abstract

The utility model provides an optical lens. The optical lens can be used for near-infrared band imaging, the optical lens comprises a lens barrel, a lens group and a spacing element group, the lens group and the spacing element group are located in the lens barrel, and a first spacing element is located between a first lens and a second lens and makes contact with one part of the image side face of the first lens; the minimum distance EP01 between the object side end face of the lens barrel and the first spacing element in the extension direction of the optical axis, the maximum thickness CP1 of the first spacing element, and the air interval T12 between the first lens and the second lens on the optical axis satisfy the following condition: 0.56 < = EP01 / (T12 + CP1) < = 1.01. The curvature radius R1 of the object side face of the first lens, the refractive index N1 of the first lens and the inner diameter d1s of the object side face of the first spacing element meet the condition that R1 * N1 / d1s is larger than or equal to-4.44 and smaller than or equal to-1.71. According to the utility model, the problem of serious stray light caused by reduction of aberration of an optical lens in the prior art is solved.

Description

Technical Field

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

[0002] With the development of technology, more and more electronic products have camera functions, and users' requirements for the optical lenses installed in these products are gradually increasing, demanding high definition from the lenses. To improve the image quality of an optical lens, its aberrations can be addressed. However, this process may result in more stray light reflected between the lenses, leading to severe stray light.

[0003] In other words, existing optical lenses suffer from severe stray light issues in their efforts to reduce aberrations. Utility Model Content

[0004] The main objective of this invention is to provide an optical lens to solve the problem of severe stray light caused by optical lenses in the prior art in order to reduce aberrations.

[0005] To achieve the above objectives, according to one aspect of the present invention, an optical lens is provided. The optical lens can be used for near-infrared imaging. The optical lens includes a lens barrel and a lens group and a spacer element group located within the lens barrel. The lens group consists of four lenses, including a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the extension direction of the optical axis. The spacer element group includes at least a first spacer element, which is located between the first lens and the second lens and contacts a portion of the image-side surface of the first lens. The minimum distance EP01 between the object-side end face of the lens barrel and the first spacer element in the extension direction of the optical axis, the maximum thickness CP1 of the first spacer element, and the air gap T12 between the first lens and the second lens on the optical axis satisfy the following: 0.56≤EP01 / (T12+CP1)≤1.01. The radius of curvature R1 of the object-side surface of the first lens, the refractive index N1 of the first lens, and the inner diameter d1s of the object-side surface of the first spacer element satisfy the following: -4.44≤R1*N1 / d1s≤-1.71.

[0006] According to another aspect of the present invention, an optical lens is provided, which can be used for near-infrared imaging. The optical lens includes a lens barrel and a lens group and a spacer element group located within the lens barrel. The lens group consists of four lenses, including a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the extension direction of the optical axis. The spacer element group includes at least a third spacer element, which is located between the third lens and the fourth lens and contacts a portion of the image-side surface of the third lens. The air gap T34 between the third lens and the fourth lens on the optical axis and the maximum thickness CP3 of the third spacer element satisfy the following condition: 0.07≤T34 / CP3≤2.05. The outer diameter D3m of the image-side surface of the third spacer element, the inner diameter d3m of the image-side surface of the third spacer element, and the radius of curvature R7 of the object-side surface of the fourth lens satisfy the following condition: 0.28≤R7 / (D3m-d3m)≤1.84.

[0007] According to another aspect of the present invention, an optical lens is provided, which can be used for near-infrared imaging. The optical lens includes a lens barrel and a lens group and a spacer element group located within the lens barrel. The lens group consists of four lenses, including a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the extension direction of the optical axis. The spacer element group includes at least a first spacer element, a second spacer element, and a third spacer element. The first spacer element is located between the first lens and the second lens and contacts a portion of the image-side surface of the first lens. The second spacer element is located between the second lens and the third lens and contacts the image-side surface of the second lens. A portion of the surface is in contact, and the third spacer element is located between the third lens and the fourth lens and in contact with a portion of the image-side surface of the third lens; the inner diameter d1m of the image-side surface of the first spacer element, the inner diameter d3s of the object-side surface of the third spacer element, the radius of curvature R3 of the object-side surface of the second lens, and the radius of curvature R6 of the image-side surface of the third lens satisfy: -3.03≤R3 / d1m+R6 / d3s≤-2.14; the radius of curvature R4 of the image-side surface of the second lens, the refractive index N2 of the second lens, and the inner diameter d2s of the object-side surface of the second spacer element satisfy: -0.8≤R4*N2 / d2s≤5.32.

[0008] Furthermore, the radius of curvature R2 of the image side of the first lens, the outer diameter D1s of the object side of the first spacer element, and the inner diameter d1s of the object side of the first spacer element satisfy the following: 1.06≤|R2| / (D1s-d1s)≤3.74.

[0009] Furthermore, the radius of curvature R3 of the object side of the second lens and the inner diameter d1m of the image side of the first spacer element satisfy the following condition: -2.65≤R3 / d1m≤-1.53.

[0010] Furthermore, the inner diameter d0s of the object-side end face of the lens barrel and the radius of curvature R1 of the object-side surface of the first lens satisfy the following condition: -0.9≤d0s / R1≤-0.35.

[0011] Furthermore, the outer diameter D0m of the image-side end face of the lens tube and the radius of curvature R8 of the image-side surface of the fourth lens satisfy the following condition: 2.65≤D0m / R8≤7.52.

[0012] Furthermore, the spacer element group also includes a second spacer element, which is located between the second lens and the third lens and contacts a portion of the image side surface of the second lens. The radius of curvature R4 of the image side surface of the second lens, the outer diameter D1m of the image side surface of the first spacer element, and the outer diameter D2s of the object side surface of the second spacer element satisfy the following condition: 1.34≤|R4| / (D2s-D1m)≤7.89.

[0013] Furthermore, the spacer group also includes a second spacer element, which is located between the second lens and the third lens and contacts a portion of the image side of the second lens. The minimum distance EP12 between the first spacer element and the second spacer element in the extension direction of the optical axis and the air gap T12 between the first lens and the second lens in the optical axis satisfy: 0.4≤EP12 / T12≤1.03.

[0014] Furthermore, the spacer element group also includes a third spacer element, which is located between the third lens and the fourth lens and contacts a portion of the image side of the third lens. The radius of curvature R5 of the object side of the third lens, the refractive index N3 of the third lens, and the outer diameter D3s of the object side of the third spacer element satisfy the following: -0.26≤R5*N3 / D3s≤0.31.

[0015] Furthermore, the spacer group also includes a third spacer element, which is located between the third lens and the fourth lens and contacts a portion of the image side of the third lens. The radius of curvature R6 of the image side of the third lens and the inner diameter d3s of the object side of the third spacer element satisfy the following: -0.7≤R6 / d3s≤-0.38.

[0016] Furthermore, the spacer group also includes a third spacer element, which is located between the third lens and the fourth lens and contacts a portion of the image-side surface of the third lens. The outer diameter D3m of the image-side surface of the third spacer element, the inner diameter d3m of the image-side surface of the third spacer element, and the radius of curvature R7 of the object-side surface of the fourth lens satisfy the following: 0.28≤R7 / (D3m-d3m)≤1.84.

[0017] Furthermore, the spacer element group also includes a second spacer element and a third spacer element. The second spacer element is located between the second lens and the third lens and contacts a portion of the image-side surface of the second lens. The third spacer element is located between the third lens and the fourth lens and contacts a portion of the image-side surface of the third lens. The minimum distance EP23 between the second spacer element and the third spacer element in the extension direction of the optical axis and the effective focal length f4 of the fourth lens satisfy the following condition: 4.51≤f4 / EP23≤17.67.

[0018] Furthermore, the spacer element group also includes a second spacer element and a third spacer element. The second spacer element is located between the second lens and the third lens and contacts a portion of the image-side surface of the second lens. The third spacer element is located between the third lens and the fourth lens and contacts a portion of the image-side surface of the third lens. The minimum distance EP23 between the second spacer element and the third spacer element in the extension direction of the optical axis, the combined focal length f34 of the third lens and the fourth lens, and the air gap T34 between the third lens and the fourth lens in the optical axis satisfy the following: 1.09≤f34 / (EP23+T34)≤8.83.

[0019] Furthermore, the fourth lens has positive optical power.

[0020] Furthermore, the optical lens satisfies at least one of the following: the object-side surface of the first lens is concave; the object-side surface of the second lens is concave; the image-side surface of the third lens is convex; the object-side surface of the fourth lens is convex; and the image-side surface of the fifth lens is concave.

[0021] Applying the technical solution of this utility model, the optical lens can be used for near-infrared imaging. The optical lens includes a lens barrel and a lens group and a spacer element group located inside the lens barrel. The lens group consists of four lenses, including a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the extension direction of the optical axis. The spacer element group includes at least a first spacer element, which is located between the first lens and the second lens and contacts a portion of the image side surface of the first lens. The minimum distance EP01 between the object side end face of the lens barrel and the first spacer element in the extension direction of the optical axis, the maximum thickness CP1 of the first spacer element, and the air gap T12 between the first lens and the second lens on the optical axis satisfy the following: 0.56≤EP01 / (T12+CP1)≤1.01. The radius of curvature R1 of the object side surface of the first lens, the refractive index N1 of the first lens, and the inner diameter d1s of the object side surface of the first spacer element satisfy the following: -4.44≤R1*N1 / d1s≤-1.71.

[0022] The optical lens of this application consists of a lens barrel, four lenses, and at least one spacer element. When the minimum distance EP01 between the object-side end face of the lens barrel and the first spacer element in the direction of optical axis extension, the maximum thickness CP1 of the first spacer element, and the air gap T12 between the first lens and the second lens in the optical axis satisfy the condition that 0.56≤EP01 / (T12+CP1)≤1.01, the range of the air gap between the first lens and the second lens can be limited. This is beneficial for controlling the field curvature caused by the air gap between the first lens and the second lens, thereby effectively controlling the field curvature of the optical lens and reducing the aberration of the optical lens. However, this can easily lead to the reflection of stray light in the area and position between the first lens and the second lens, resulting in severe stray light. To reduce the generation of stray light, this application constrains R1*N1 / d1s within a reasonable range to adjust the deflection angle of light passing through the first lens, ensuring that the light does not undergo large-angle deflection, avoiding the light from being deflected to areas outside the effective diameter to generate reflected stray light, and ensuring that the first spacer element blocks the non-effective diameter area of ​​the first lens, further reducing the generation of stray light, thereby ensuring the imaging quality of the optical lens. Attached Figure Description

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

[0024] Figure 1 A dimensioned diagram of an optical lens according to an alternative embodiment of the present invention is shown;

[0025] Figure 2 A schematic diagram of the structure of the optical lens of Embodiment 1-1 of this utility model is shown;

[0026] Figure 3 A schematic diagram of the optical lens structure of Embodiments 1-2 of this utility model is shown;

[0027] Figure 4 The diagram shows the structural schematics of the optical lenses of embodiments 1-3 of this utility model;

[0028] Figures 5 to 8 The on-axis chromatic aberration, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical lens of Embodiment 1 of this utility model are shown respectively.

[0029] Figure 9 A schematic diagram of the optical lens of Embodiment 2-1 of this utility model is shown;

[0030] Figure 10 A schematic diagram of the optical lens of Embodiment 2-2 of this utility model is shown;

[0031] Figure 11 A schematic diagram of the optical lens structure of embodiments 2-3 of this utility model is shown;

[0032] Figures 12 to 15 The on-axis chromatic aberration, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical lens of Embodiment 2 of this utility model are shown respectively.

[0033] Figure 16 A schematic diagram of the structure of the optical lens of Embodiment 3-1 of this utility model is shown;

[0034] Figure 17 A schematic diagram of the optical lens structure of Embodiment 3-2 of this utility model is shown;

[0035] Figure 18 A schematic diagram of the optical lens of Embodiment 3-3 of this utility model is shown;

[0036] Figures 19 to 22 The on-axis chromatic aberration, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical lens of Embodiment 3 of this utility model are shown respectively.

[0037] Figure 23 This invention illustrates the optical path diagram of a portion of the light rays within the optical lens of an optional embodiment of the present invention.

[0038] Figure 24 It shows Figure 23 Stray light pattern of a medium-sized optical lens;

[0039] Figure 25 The optical path diagram of a portion of the light rays within an optical lens is shown in an example;

[0040] Figure 26 It shows Figure 25 Stray light pattern of a medium-sized optical lens;

[0041] Figure 27 The optical path diagram of a portion of the light rays within an optical lens is shown in an example;

[0042] Figure 28 It shows Figure 27 A stray light pattern on a medium optical lens.

[0043] The above figures include the following reference numerals:

[0044] E1, First lens; P1, First spacer element; P1b, First auxiliary spacer element; E2, Second lens; P2, Second spacer element; E3, Third lens; P3, Third spacer element; P3b, Third auxiliary 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

[0045] 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.

[0046] 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.

[0047] In this utility model, 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 used to limit this utility model.

[0048] 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.

[0049] 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.

[0050] In this paper, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the 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 the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface shape in the paraxial region can be determined according to the judgment method commonly known in the art, using the R value (R refers to the radius of curvature of the paraxial region, usually the R value in the lens database of optical software) to determine concavity or convexity. For the object side, 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, 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. In this application, the left side is the object side, and the right side is the image side.

[0051] In order to solve the problem of severe stray light caused by optical lenses in order to reduce aberrations, this utility model provides an optical lens.

[0052] like Figures 1 to 22 As shown, the optical lens can be used for near-infrared imaging. The optical lens includes a lens barrel and a lens group and a spacer element group located inside the lens barrel. The lens group consists of four lenses, including a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the extension direction of the optical axis. The spacer element group includes at least a first spacer element, which is located between the first lens and the second lens and contacts a portion of the image side surface of the first lens. The minimum distance EP01 between the object side end face of the lens barrel and the first spacer element in the extension direction of the optical axis, the maximum thickness CP1 of the first spacer element, and the air gap T12 between the first lens and the second lens on the optical axis satisfy the following: 0.56≤EP01 / (T12+CP1)≤1.01. The radius of curvature R1 of the object side surface of the first lens, the refractive index N1 of the first lens, and the inner diameter d1s of the object side surface of the first spacer element satisfy the following: -4.44≤R1*N1 / d1s≤-1.71.

[0053] The optical lens of this application consists of a lens barrel, four lenses, and at least one spacer element. When the minimum distance EP01 between the object-side end face of the lens barrel and the first spacer element in the direction of optical axis extension, the maximum thickness CP1 of the first spacer element, and the air gap T12 between the first lens and the second lens in the optical axis satisfy the condition that 0.56≤EP01 / (T12+CP1)≤1.01, the range of the air gap between the first lens and the second lens can be limited. This is beneficial for controlling the field curvature caused by the air gap between the first lens and the second lens, thereby effectively controlling the field curvature of the optical lens and reducing the aberration of the optical lens. However, this can easily lead to the reflection of stray light in the area and position between the first lens and the second lens, resulting in severe stray light. To reduce the generation of stray light, this application constrains R1*N1 / d1s within a reasonable range to adjust the deflection angle of light passing through the first lens, ensuring that the light does not undergo large-angle deflection, avoiding the light from being deflected to areas outside the effective diameter to generate reflected stray light, and ensuring that the first spacer element blocks the non-effective diameter area of ​​the first lens, further reducing the generation of stray light, thereby ensuring the imaging quality of the optical lens.

[0054] In addition, please refer to Table 1 below and Figures 23 to 28 As shown, Figure 23 A partial optical path diagram of an optical lens is shown, satisfying EP01 / (T12+CP1)=0.87 and R1*N1 / d1s=-3.61. Figure 24 It shows Figure 23 A stray light pattern on a medium optical lens. Figure 25 A partial optical path diagram of an optical lens is shown, satisfying EP01 / (T12+CP1)=0.87 and R1*N1 / d1s=-4.8. Figure 26 It shows Figure 25 A stray light pattern on a medium optical lens. Figure 27 The diagram shows a partial optical path of the lens when EP01 / (T12+CP1)=0.87 and R1*N1 / d1s=-1.2. Figure 28 It shows Figure 27 A stray light pattern on a medium optical lens.

[0055] Depend on Figures 23 to 28As shown, when the optical lens satisfies EP01 / (T12+CP1)=0.87 and R1*N1 / d1s=-3.61, stray light energy is reduced, stray light is improved, and the performance is good. When the optical lens satisfies EP01 / (T12+CP1)=0.87 and R1*N1 / d1s=-4.8, stray light energy is strong, and stray light has a significant impact on image quality, resulting in poor performance. When the optical lens satisfies EP01 / (T12+CP1)=0.87 and R1*N1 / d1s=-1.2, stray light energy is strong, and stray light has a significant impact on image quality, resulting in poor performance. Therefore, when R1*N1 / d1s is in the range of -4.44 to -1.71, the optical lens has a better stray light improvement effect. Therefore, this application reasonably constrains the relationship between the radius of curvature of the object side surface of the first lens, the refractive index of the first lens, and the inner diameter of the object side surface of the first spacer element by constraining -4.44≤R1*N1 / d1s≤-1.71. This ensures that the first spacer element blocks the non-effective diameter region of the first lens while absorbing stray light generated in the effective diameter region of the first lens and controlling the deflection angle of the light in the first lens, thereby further reducing stray light generated in the effective diameter region of the first lens and ensuring imaging quality.

[0056]

[0057] Table 1

[0058] It should be noted that this application limits R1*N1 / d1s within a reasonable range and optimizes the relationship between the first spacer element and the first lens to improve stray light generated in the effective diameter region of the first lens. This addresses the stray light problem caused by EP01 / (T12+CP1) being in the range of 0.56 to 1.01. When R1*N1 / d1s meets the above-mentioned range, the purpose of improving stray light can be achieved, without relying on the optical power or surface shape of the lens. The optical power and surface shape of the lens are further optimizations of the optical lens based on these factors. Each lens can be positive or negative according to the design requirements of the actual optical system, and the surface shape of each lens can also be convex or concave according to the design requirements of the optical system. When the optical system satisfies: 2.6≤d0m / |R8|≤8.67; -4.44≤R1*N1 / d1s≤-1.71, the optical lens can reduce the influence of stray light while reducing aberrations.

[0059] For example, in some optional embodiments, the fourth lens has a positive optical power. By constraining the optical power of the fourth lens, it is beneficial for light rays to converge after exiting the fourth lens, thus facilitating adaptation to the chip at the imaging surface. As another example, in some optional embodiments, the object-side surface of the first lens is concave; the object-side surface of the second lens is concave; the image-side surface of the third lens is convex; the object-side surface of the fourth lens is convex; and the image-side surface of the fourth lens is concave. By reasonably constraining the surface shape of each lens, it is beneficial to reasonably constrain the light path, ensuring a smooth light transition and facilitating aberration correction. The optical lens can be simulated using software and / or tools such as ZEMAX and CODEV. Preferably, the optical lens can be simulated using CODEV. During the simulation process using software and / or tools such as those described above, the surface shape of each lens can be simulated and appropriately adjusted according to the built-in surface shape of the software and / or tools used.

[0060] In some optional embodiments, the radius of curvature R2 of the image-side surface of the first lens, the outer diameter D1s of the object-side surface of the first spacer element, and the inner diameter d1s of the object-side surface of the first spacer element satisfy the following: 1.06 ≤ |R2| / (D1s-d1s) ≤ 3.74. By constraining |R2| / (D1s-d1s) within a reasonable range, not only can the bearing width between the first spacer element and the first lens be guaranteed, ensuring the stability of the first lens bearing, but the angle at which light exits from the image-side surface of the first lens can also be controlled, ensuring that the imaging light rays smoothly enter the second lens. In addition to absorbing the large-angle deflected light rays exiting the first lens, the first spacer element can also absorb stray light generated at the edge of the effective diameter of the first lens, which is beneficial to further reduce stray light.

[0061] In some alternative embodiments, the radius of curvature R3 of the object-side surface of the second lens and the inner diameter d1m of the image-side surface of the first spacer element satisfy the following condition: -2.65 ≤ R3 / d1m ≤ -1.53. By constraining R3 / d1m within a reasonable range, the image-side surface of the first spacer element can block the non-effective diameter region of the object-side surface of the second lens, while controlling the divergence angle of light rays after passing through the object-side surface of the second lens, thereby reducing stray light generated in the non-effective diameter region of the second lens.

[0062] In some optional embodiments, the inner diameter d0s of the object-side end face of the lens barrel and the radius of curvature R1 of the object-side surface of the first lens satisfy the following relationship: -0.9 ≤ d0s / R1 ≤ -0.35. By constraining d0s / R1 within a reasonable range, it is beneficial to control the light-transmitting aperture of the object-side end face of the lens barrel, preventing the lens barrel from blocking the imaging light and ensuring the imaging brightness of the optical lens. Simultaneously, controlling the degree of light refraction by the object-side surface of the first lens facilitates the entry of large-angle light into the optical lens, increasing the field of view and relative brightness, thereby improving the imaging quality of the optical lens. It also prevents the first lens from protruding from the lens barrel, avoiding damage to the first lens and reducing the occurrence of aesthetic defects.

[0063] In some alternative embodiments, the outer diameter D0m of the image-side end face of the lens barrel and the radius of curvature R8 of the image-side surface of the fourth lens satisfy the following condition: 2.65 ≤ D0m / R8 ≤ 7.52. By constraining D0m / R8 within a reasonable range, it is beneficial to control the exit angle of light through the fourth lens, to ensure the converging effect of light on the imaging surface, and thus to facilitate the adaptation of the optical lens's exit angle to the chip. At the same time, limiting the size of the lens barrel is beneficial for miniaturization of the lens barrel while ensuring the assemblability of the optical lens.

[0064] In some optional embodiments, the spacer element group further includes a second spacer element located between the second lens and the third lens and in contact with a portion of the image-side surface of the second lens. The radius of curvature R4 of the image-side surface of the second lens, the outer diameter D1m of the image-side surface of the first spacer element, and the outer diameter D2s of the object-side surface of the second spacer element satisfy the following condition: 1.34 ≤ |R4| / (D2s-D1m) ≤ 7.89. By constraining |R4| / (D2s-D1m) within a reasonable range, it is beneficial to control the difference between the outer diameter of the image-side surface of the first spacer element and the outer diameter of the object-side surface of the second spacer element, ensuring the bearing area of ​​the first and second spacers on the second lens, reducing the occurrence of uneven force on the object-side and image-side surfaces of the second lens, ensuring the stability of the second lens assembly, controlling the radius of curvature of the image-side surface of the second lens, ensuring that light rays exit smoothly from the second lens, and reducing the risk of the first and second spacers blocking light rays passing through the second lens.

[0065] In some optional embodiments, the spacer element group further includes a second spacer element located between the second lens and the third lens and in contact with a portion of the image-side surface of the second lens. The minimum distance EP12 between the first and second spacer elements in the extension direction of the optical axis and the air gap T12 between the first and second lenses in the optical axis satisfy the following: 0.4 ≤ EP12 / T12 ≤ 1.03. Constraining EP12 / T12 within a reasonable range not only constrains the relative positional relationship between the first and second spacer elements, ensuring the stability of the support for the second lens, but also constrains the edge thickness of the second lens to ensure the fitting accuracy between the second lens and the lens barrel. Simultaneously, it avoids interference between the first and second lenses, reduces the sensitivity of the second lens, and improves the stability of the second lens assembly, thereby contributing to the stability of the optical performance of the optical lens.

[0066] In some optional embodiments, the spacer element group further includes a third spacer element located between the third lens and the fourth lens and in contact with a portion of the image-side surface of the third lens. The radius of curvature R5 of the object-side surface of the third lens, the refractive index N3 of the third lens, and the outer diameter D3s of the object-side surface of the third spacer element satisfy the following condition: -0.26 ≤ R5*N3 / D3s ≤ 0.31. Constraining R5*N3 / D3s within a reasonable range helps ensure the bearing width of the third spacer element on the third lens, thus ensuring the stability of the third lens assembly. It also helps improve the surface profile of the object-side surface of the third lens, allowing control over the refraction angle of light rays passing through it. This helps reduce the energy of ghost light spots reflected from the effective path of the third lens, thereby improving image quality. Furthermore, the third spacer element can also absorb some of the stray light emitted through the third lens, reducing stray light.

[0067] In some optional embodiments, the spacer element group further includes a third spacer element located between the third lens and the fourth lens and in contact with a portion of the image-side surface of the third lens. The radius of curvature R6 of the image-side surface of the third lens and the inner diameter d3s of the object-side surface of the third spacer element satisfy the following condition: -0.7 ≤ R6 / d3s ≤ -0.38. By constraining R6 / d3s within a reasonable range, the radius of curvature of the image-side surface of the third lens and the occlusion range of the third spacer element on the image-side surface of the third lens are limited. This ensures that the imaging light rays exiting the third lens pass smoothly through the inner diameter of the third spacer element without being blocked by it. Simultaneously, it also ensures that stray light paths at the edge of the effective diameter of the image-side surface of the third lens are intercepted by the third spacer element, thus guaranteeing the image quality of the lens.

[0068] In some optional embodiments, the spacer element group further includes a third spacer element located between the third lens and the fourth lens and in contact with a portion of the image-side surface of the third lens. The outer diameter D3m of the image-side surface of the third spacer element, the inner diameter d3m of the image-side surface of the third spacer element, and the radius of curvature R7 of the object-side surface of the fourth lens satisfy the following: 0.28 ≤ R7 / (D3m-d3m) ≤ 1.84. Constraining R7 / (D3m-d3m) within a reasonable range ensures sufficient adsorption space for the third spacer element, which is beneficial for improving the stability of the optical lens assembly and ensuring the feasibility of the assembly process. Simultaneously, it ensures that the imaging light emitted from the third lens is smoothly converged to the rear optical system via the object side of the fourth lens, guaranteeing an accurate light transmission path.

[0069] In some optional embodiments, the spacer element group further includes a second spacer element and a third spacer element. The second spacer element is located between the second and third lenses and contacts a portion of the image-side surface of the second lens. The third spacer element is located between the third and fourth lenses and contacts a portion of the image-side surface of the third lens. The minimum distance EP23 between the second and third spacer elements in the extension direction of the optical axis and the effective focal length f4 of the fourth lens satisfy the following condition: 4.51 ≤ f4 / EP23 ≤ 17.67. Constraining f4 / EP23 within a reasonable range helps control the deflection angle of light passing through the fourth lens, ensuring that the light rays are converged when exiting the fourth lens. This limits the incident angle of the light rays exiting the fourth lens onto the chip on the imaging surface, and also limits the structural support force between the second and third spacer elements on the fourth lens, ensuring the support stability of the fourth lens. Simultaneously, it also ensures that the edge thickness of the third lens is within a reasonable range, guaranteeing the support stability and formability of the third lens.

[0070] In some optional embodiments, the spacer element group further includes a second spacer element and a third spacer element. The second spacer element is located between the second and third lenses and contacts a portion of the image-side surface of the second lens. The third spacer element is located between the third and fourth lenses and contacts a portion of the image-side surface of the third lens. The minimum distance EP23 between the second and third spacer elements in the extension direction of the optical axis, the combined focal length f34 of the third and fourth lenses, and the air gap T34 between the third and fourth lenses in the optical axis satisfy the following: 1.09 ≤ f34 / (EP23+T34) ≤ 8.83. By constraining f34 / (EP23+T34) within a reasonable range, the load-bearing force provided by the structure between the second and third spacer elements can be limited, avoiding the influence of lens edge thickness manufacturing tolerances, air gaps, surface shapes, and other factors on the assembled optical performance during assembly. This ensures the converging effect of light after passing through the third and fourth lenses and improves the stability of the optical lens.

[0071] According to another aspect of the present invention, an optical lens is provided, which can be used for near-infrared imaging. The optical lens includes a lens barrel and a lens group and a spacer element group located within the lens barrel. The lens group consists of four lenses, including a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the extension direction of the optical axis. The spacer element group includes at least a third spacer element, which is located between the third lens and the fourth lens and contacts a portion of the image-side surface of the third lens. The air gap T34 between the third lens and the fourth lens on the optical axis and the maximum thickness CP3 of the third spacer element satisfy the following condition: 0.07≤T34 / CP3≤2.05. The outer diameter D3m of the image-side surface of the third spacer element, the inner diameter d3m of the image-side surface of the third spacer element, and the radius of curvature R7 of the object-side surface of the fourth lens satisfy the following condition: 0.28≤R7 / (D3m-d3m)≤1.84.

[0072] The optical lens of this application consists of a lens barrel, four lenses, and at least one spacer element. When the air gap T34 between the third and fourth lenses on the optical axis satisfies the condition 0.07 ≤ T34 / CP3 ≤ 2.05, the gap between the third and fourth lenses can be constrained, reducing the impact of air gap variations during assembly on the optical performance of the lens. However, during assembly, the fourth lens is prone to interfering with the third lens, increasing the assembly difficulty. This application constrains R7 / (D3m-d3m) within a reasonable range, ensuring sufficient space for the fourth lens and the third spacer element to adhere, facilitating their adhesion, reducing assembly difficulty, and improving assembly stability. Simultaneously, by controlling the radius of curvature of the object-side surface of the fourth lens, interference between the fourth lens and the third lens is reduced while maintaining imaging performance, further lowering the assembly difficulty.

[0073] Of course, this embodiment may also include other parametric expressions as described in the above embodiments, which will not be elaborated here.

[0074] According to another aspect of the present invention, an optical lens is provided, which can be used for near-infrared imaging. The optical lens includes a lens barrel and a lens group and a spacer element group located within the lens barrel. The lens group consists of four lenses, including a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the extension direction of the optical axis. The spacer element group includes at least a first spacer element, a second spacer element, and a third spacer element. The first spacer element is located between the first lens and the second lens and contacts a portion of the image-side surface of the first lens. The second spacer element is located between the second lens and the third lens and contacts the image-side surface of the second lens. A portion of the surface is in contact, and the third spacer element is located between the third lens and the fourth lens and in contact with a portion of the image-side surface of the third lens; the inner diameter d1m of the image-side surface of the first spacer element, the inner diameter d3s of the object-side surface of the third spacer element, the radius of curvature R3 of the object-side surface of the second lens, and the radius of curvature R6 of the image-side surface of the third lens satisfy: -3.03≤R3 / d1m+R6 / d3s≤-2.14; the radius of curvature R4 of the image-side surface of the second lens, the refractive index N2 of the second lens, and the inner diameter d2s of the object-side surface of the second spacer element satisfy: -0.8≤R4*N2 / d2s≤5.32.

[0075] The optical lens of this application consists of a lens barrel, four lenses, and at least one spacer element. When the inner diameter d1m of the image-side surface of the first spacer element, the inner diameter d3s of the object-side surface of the third spacer element, the radius of curvature R3 of the object-side surface of the second lens, and the radius of curvature R6 of the image-side surface of the third lens satisfy the condition -3.03 ≤ R3 / d1m + R6 / d3s ≤ -2.14, it is beneficial for diffusing light entering the rear optical system through the first lens, thus ensuring the field of view of the optical lens. However, during the diffusion of light from the object-side surface of the second lens to the image-side surface of the third lens, large-angle deflected light is easily generated, resulting in severe stray light. To reduce the generation of stray light, this application constrains R4*N2 / d2s within a reasonable range to adjust the deflection angle of light rays exiting from the image side of the second lens, reducing large-angle deflected light rays, preventing light rays from being deflected to areas outside the effective diameter and generating reflected stray light, ensuring that the second spacer element blocks the non-effective diameter area of ​​the second lens, further reducing the generation of stray light, thereby ensuring the imaging quality of the optical lens.

[0076] Of course, this embodiment may also include other parametric expressions as described in the above embodiments, which will not be elaborated here.

[0077] In some alternative embodiments, the above-mentioned multiple lenses may include at least one tangent lens. The outer peripheral surface of the tangent lens may have a tangent portion and a non-tangent portion, and the outer diameter of the tangent portion of the lens is smaller than the outer diameter of the non-tangent portion of the lens. When the outer peripheral surface of the lens has a tangent portion, the outer diameter of the lens usually refers to the outer diameter of the non-tangent portion of the lens.

[0078] In some alternative embodiments, at least one of the plurality of spacers described above may be a truncated spacer. The outer peripheral surface of the truncated spacer may have a truncated portion and a non-truncated portion, and the outer diameter of the truncated portion of the truncated spacer is smaller than the outer diameter of the non-truncated portion of the truncated spacer. The outer diameter of the spacer typically refers to the maximum outer diameter of the non-truncated portion.

[0079] Optionally, the aforementioned optical lens may also include protective glass for protecting the photosensitive element located on the imaging plane.

[0080] It should be noted that each lens consists of a central optical effective diameter region and an edge structure region. The edge structure region is located on the outer periphery of the central optical effective diameter region and is arranged circumferentially around it. The central optical effective diameter region is used for the passage of imaging light rays, while the edge structure region is not used for the passage of imaging light rays but is used to contact the lens barrel, adjacent lenses, or adjacent spacer elements. The edge structure region is also called the non-effective diameter region.

[0081] 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.

[0082] 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.

[0083] Figure 1 A schematic diagram showing the dimensions of an optical lens according to this application is provided. Figure 1 The parameters d1s, d1m, D1s, D1m, D2s, d3s, d3m, D3s, D3m, d0s, D0m, CP1, EP01, EP12, and EP23 are clearly and intuitively illustrated to provide a clear 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.

[0084] 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.

[0085] It should be noted that in the following Embodiment 1, there are three examples: Embodiment 1-1, Embodiment 1-2, and Embodiment 1-3; in Embodiment 2, there are three examples: Embodiment 2-1, Embodiment 2-2, and Embodiment 2-3; and in Embodiment 3, there are three examples: Embodiment 3-1, Embodiment 3-2, and Embodiment 3-3. In the two examples within the same embodiment, the radii of curvature, center thickness, and other parameters of the first to fourth lenses, as well as the spacing distance and higher-order coefficients between the lenses, are the same. However, the thickness, inner diameter, and outer diameter of the lens barrel, the first spacer element, the second spacer element, and the third spacer element, and the shape of some lenses are different. In other words, the main structure used for imaging is the same, but the auxiliary structures used for imaging are different.

[0086] It should be noted that any of the embodiments described in Examples 1 to 3 below are applicable to all implementation methods of this application.

[0087] Example 1

[0088] like Figures 2 to 5 As shown, the optical lens of Embodiment 1 is described. Figure 2 A schematic diagram of the optical lens of Embodiment 1-1 is shown. Figure 3 A schematic diagram of the optical lens structure of Embodiments 1-2 is shown. Figure 4 A schematic diagram of the optical lens structure of Embodiments 1-3 is shown.

[0089] like Figures 2 to 4 As shown, the optical lens includes a lens barrel, four lenses, and multiple spacer elements. The lens barrel includes a first lens E1, a first spacer element P1, a first auxiliary spacer element P1b, a second lens E2, a second spacer element P2, a third lens E3, a third spacer element P3, and a fourth lens E4 arranged sequentially from the object side to the image side.

[0090] like Figure 2 The diagram shows a schematic of the optical lens in Embodiment 1-1. In this example, the optical lens further includes a third auxiliary spacer element P3b. The object-side surface S1 of the first lens abuts against the lens barrel portion. The object-side surface and image-side surface of the first spacer element P1 abut against the image-side surface S2 of the first lens and the object-side surface of the first auxiliary spacer element, respectively. The image-side surface of the first auxiliary spacer element P1b abuts against the object-side surface S3 of the second lens. The object-side surface and image-side surface of the second spacer element abut against the image-side surface S4 of the second lens and the object-side surface S5 of the third lens, respectively. The object-side surface and image-side surface of the third spacer element abut against the image-side surface S6 of the third lens and the object-side surface of the third auxiliary spacer element, respectively. The image-side surface of the third auxiliary spacer element abuts against the object-side surface S7 of the fourth lens, and the image-side surface S8 of the fourth lens is spaced apart from the lens barrel.

[0091] like Figure 3 The diagram shown is a structural schematic of the optical lens of Embodiment 1-2. In this example, the bearing and contact method of each spacer element is the same as that of Embodiment 1-1, and can be referred to the relevant description in Embodiment 1-1, which will not be repeated here.

[0092] like Figure 4 The diagram shown is a structural schematic of the optical lens in Embodiments 1-3. In this example, the optical lens does not have a third auxiliary spacer element P3b. The image side of the third spacer element abuts against the object side S7 of the fourth lens. The bearing and abutting methods of the other spacers are the same as in Embodiments 1-1. Please refer to the relevant description in Embodiments 1-1. It will not be repeated here.

[0093] In summary, the structural parameters of the optical lens of Embodiment 1 under Embodiments 1-1, 1-2, and 1-3 are shown in Table 9.

[0094] In Embodiment 1, the object-side surface S1 of the first lens is concave, and the image-side surface S2 of the first lens is concave. The object-side surface S3 of the second lens is concave, and the image-side surface S4 of the second lens is convex. The object-side surface S5 of the third lens is concave, and the image-side surface S6 of the third lens is convex. The object-side surface S7 of the fourth lens is convex, and the image-side surface S8 of the fourth lens is concave. In Table 2 below, S9 and S10 can be the surfaces of filters or protective glass, while S11 is the imaging surface, and STO is the aperture stop, not shown in the figure.

[0095] Table 2 shows the basic structural parameters of the optical lens in Embodiment 1, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0096]

[0097] Table 2

[0098] In Embodiment 1, the object-side surface and image-side surface of the first lens E1 to the fourth lens E4 are both aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0099]

[0100] Where x is the distance vector from the vertex of the aspherical surface at a height h along the optical axis; 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 1 above; k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 3 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, and A28 that can be used for each aspherical mirror S1-S8 in Example 1.

[0101]

[0102]

[0103] Table 3

[0104] 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. Figure 8 The magnification chromatic aberration curve of the optical lens of Embodiment 1 is shown, which represents the deviation of different image heights on the imaging plane after light passes through the lens.

[0105] according to Figures 5 to 8 As can be seen, the optical lens given in Example 1 can achieve good imaging quality.

[0106] Example 2

[0107] like Figures 9 to 15 As shown, the optical lens of Embodiment 2 is described. Figure 9 A schematic diagram of the optical lens of Embodiment 2-1 is shown. Figure 10 A schematic diagram of the optical lens of Embodiment 2-2 is shown. Figure 11 A schematic diagram of the optical lens of Embodiments 2-3 is shown.

[0108] like Figures 9 to 11 As shown, the optical lens includes a lens barrel, four lenses, and multiple spacer elements. The lens barrel includes a first lens E1, a first spacer element P1, a first auxiliary spacer element P1b, a second lens E2, a second spacer element P2, a third lens E3, a third spacer element P3, and a fourth lens E4 arranged sequentially from the object side to the image side.

[0109] like Figure 9The diagram shown is a schematic representation of the optical lens in Embodiment 2-1. In this example, the optical lens further includes a third auxiliary spacer element P3b. The object-side surface S1 of the first lens abuts against the lens barrel portion. The object-side surface of the first spacer element P1 abuts against the image-side surface S2 of the first lens. The object-side surface and image-side surface of the first auxiliary spacer element P1b abut against the image-side surface of the first spacer element and the object-side surface S3 of the second lens, respectively. The object-side surface and image-side surface of the second spacer element abut against the image-side surface S4 of the second lens and the object-side surface S5 of the third lens, respectively. The object-side surface and image-side surface of the third spacer element abut against the image-side surface S6 of the third lens and the object-side surface of the third auxiliary spacer element, respectively. The image-side surface of the third auxiliary spacer element abuts against the object-side surface S7 of the fourth lens, and the image-side surface S8 of the fourth lens is spaced apart from the lens barrel.

[0110] like Figure 10 The diagram shown is a schematic diagram of the optical lens structure of Embodiment 2-2. In this example, the optical lens does not have a third auxiliary spacer element P3b. The image side of the third spacer element abuts against the object side S7 of the fourth lens. The abutting and supporting methods of the other spacers are the same as in Embodiment 1-1, and can be referred to the relevant description in Embodiment 1-1, which will not be repeated here.

[0111] like Figure 11 The diagram shown is a structural schematic of the optical lens in Embodiment 2-3. In this example, the bearing and contact method of each spacer element is the same as in Embodiment 1-1. Please refer to the relevant description in Embodiment 1-1, which will not be repeated here.

[0112] In summary, the structural parameters of the optical lens of Embodiment 2 under Embodiments 2-1, 2-2, and 2-3 are shown in Table 9.

[0113] In Embodiment 2, the object-side surface S1 of the first lens is concave, and the image-side surface S2 of the first lens is concave. The object-side surface S3 of the second lens is concave, and the image-side surface S4 of the second lens is concave. The object-side surface S5 of the third lens is convex, and the image-side surface S6 of the third lens is convex. The object-side surface S7 of the fourth lens is convex, and the image-side surface S8 of the fourth lens is concave. In Table 4 below, S9 and S10 can be the surfaces of filters or protective glass, while S11 is the imaging surface, and STO is the aperture stop, not shown in the figure.

[0114] Table 4 shows the basic structural parameters of the optical lens in Embodiment 2, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0115]

[0116] Table 4

[0117] Table 5 below shows the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, and A28 that can be used for each aspherical mirror S1-S8 in Example 2. The aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0118] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 A22 A24 A26 A28 S1 5.24E-01 -8.57E-02 1.41E-02 -6.61E-03 1.70E-03 -5.60E-04 1.57E-04 -4.47E-05 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S2 2.28E-01 -4.62E-02 -1.82E-03 -5.12E-04 9.45E-04 9.23E-05 -1.33E-04 -3.58E-06 -1.24E-05 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S3 -4.90E-03 -7.31E-05 -1.27E-05 3.78E-07 -5.93E-07 8.21E-07 9.20E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S4 -4.26E-02 2.59E-03 -2.46E-04 4.54E-05 6.54E-06 -6.56E-06 -9.00E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S5 -1.11E-01 5.17E-03 -1.34E-03 3.10E-04 -6.68E-05 -2.28E-05 -1.80E-06 -6.24E-08 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 -6.59E-03 3.97E-03 -4.98E-04 4.89E-04 4.72E-05 -1.99E-05 -2.99E-05 -1.51E-05 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S7 -1.98E-01 -8.50E-03 -2.31E-04 -3.77E-04 -1.22E-04 -2.55E-05 -3.44E-05 -1.40E-05 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S8 -1.20E-01 -1.81E-03 2.17E-03 -7.40E-04 1.80E-04 -2.74E-05 -1.55E-05 3.23E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0119] Table 5

[0120] Figure 12 The on-axis chromatic aberration curve of the optical lens of Embodiment 2 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the optical lens. Figure 13 The astigmatism curve of the optical lens of Embodiment 2 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 14 The distortion curve of the optical lens in Embodiment 2 is shown, which represents the distortion magnitude value corresponding to different field of view angles. Figure 15 The magnification chromatic aberration curve of the optical lens of Embodiment 2 is shown, which represents the deviation of different image heights on the imaging plane after light passes through the lens.

[0121] according to Figures 12 to 15 It can be seen that the optical lens given in Example 2 can achieve good imaging quality.

[0122] Example 3

[0123] like Figures 16 to 22 As shown, the optical lens of Embodiment 3 is described. Figure 16 A schematic diagram of the optical lens of Embodiment 3-1 is shown. Figure 17 A schematic diagram of the optical lens of Embodiment 3-2 is shown. Figure 18 A schematic diagram of the optical lens of Embodiment 3-3 is shown.

[0124] like Figures 16 to 18 As shown, the optical lens includes a lens barrel, four lenses, and multiple spacer elements. The lens barrel includes a first lens E1, a first spacer element P1, a first auxiliary spacer element P1b, a second lens E2, a second spacer element P2, a third lens E3, a third spacer element P3, a third auxiliary spacer element P3b, and a fourth lens E4, arranged sequentially from the object side to the image side.

[0125] like Figure 16The diagram shows a schematic of the optical lens structure of Embodiment 3-1. In this example, the object-side surface S1 of the first lens abuts against the lens barrel portion. The object-side surface and image-side surface of the first spacer element P1 abut against the image-side surface S2 of the first lens and the object-side surface of the first auxiliary spacer element, respectively. The image-side surface of the first auxiliary spacer element abuts against the object-side surface S3 of the second lens. The object-side surface and image-side surface of the second spacer element abut against the image-side surface S4 of the second lens and the object-side surface S5 of the third lens, respectively. The object-side surface and image-side surface of the third spacer element abut against the image-side surface S6 of the third lens and the object-side surface of the third auxiliary spacer element, respectively. The image-side surface of the third auxiliary spacer element abuts against the object-side surface S7 of the fourth lens, and the image-side surface S8 of the fourth lens is spaced apart from the lens barrel.

[0126] like Figure 17 The diagram shown is a structural schematic of the optical lens in Embodiment 3-2. The abutment and contact methods of each spacer element are the same as in Embodiment 3-1, and can be referred to the relevant description in Embodiment 3-1, which will not be repeated here.

[0127] like Figure 18 The diagram shown is a structural schematic of the optical lens in Embodiment 3-3. The abutment and contact method of each spacer element is the same as in Embodiment 3-1, and can be referred to the relevant description in Embodiment 3-1, which will not be repeated here.

[0128] In summary, the structural parameters of the optical lens in Embodiment 3 under Embodiments 3-1, 3-2, and 3-3 are shown in Table 9.

[0129] In Embodiment 3, the object-side surface S1 of the first lens is concave, and the image-side surface S2 of the first lens is convex. The object-side surface S3 of the second lens is concave, and the image-side surface S4 of the second lens is convex. The object-side surface S5 of the third lens is concave, and the image-side surface S6 of the third lens is convex. The object-side surface S7 of the fourth lens is convex, and the image-side surface S8 of the fourth lens is concave. In Table 6 below, S9 and S10 can be the surfaces of filters or protective glass, while S11 is the imaging surface, and STO is the aperture stop, not shown in the figure.

[0130] Table 6 shows the basic structural parameters of the optical lens in Embodiment 3, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0131]

[0132]

[0133] Table 6

[0134] Table 7 below lists the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, and A28 that can be used for each aspherical mirror S1-S8 in Example 3. The surface shape of each aspherical surface can be defined by formula (1) given in Example 1 above.

[0135] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 A22 A24 A26 A28 S1 3.70E-01 -4.14E-02 1.02E-02 -3.66E-03 7.10E-04 -2.96E-04 4.36E-05 2.74E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S2 2.02E-01 -2.76E-02 5.40E-03 -2.14E-03 5.59E-04 -1.49E-04 4.40E-05 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S3 -3.11E-03 -1.55E-04 -4.84E-05 4.21E-06 -1.99E-06 5.10E-06 6.97E-08 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S4 1.12E-01 5.65E-03 1.89E-03 6.49E-04 3.41E-04 1.36E-04 3.39E-05 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S5 2.20E-01 -3.01E-02 2.64E-03 -2.52E-03 2.34E-04 -1.17E-04 3.86E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 -4.41E-03 9.83E-03 3.27E-04 -2.49E-03 -8.44E-04 -1.02E-05 1.21E-04 2.09E-05 5.78E-06 1.81E-06 5.44E-07 2.17E-07 0.00E+00 S7 -5.93E-01 1.14E-01 -1.83E-02 4.68E-03 -1.63E-03 1.26E-03 -5.95E-04 -2.41E-05 -1.45E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S8 -5.55E-01 3.73E-02 4.16E-03 6.63E-04 -1.50E-03 1.08E-03 -2.14E-04 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0136] Table 7

[0137] Figure 19 The on-axis chromatic aberration curve of the optical lens of Embodiment 3 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the optical lens. Figure 20 The astigmatism curve of the optical lens of Embodiment 3 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 21 The distortion curve of the optical lens in Embodiment 3 is shown, which represents the distortion magnitude value corresponding to different field of view angles. Figure 22 The magnification chromatic aberration curve of the optical lens of Embodiment 3 is shown, which represents the deviation of different image heights on the imaging plane after light passes through the lens.

[0138] according to Figures 19 to 22 It can be seen that the optical lens given in Example 3 can achieve good imaging quality.

[0139] In summary, the optical lenses of Embodiments 1 to 3 respectively satisfy the relationships shown in Table 8.

[0140]

[0141]

[0142] Table 8

[0143] Table 9 shows some parameters (unit: mm) of the optical lenses of Examples 1 to 3.

[0144] Example parameters 1-1 1-2 1-3 2-1 2-2 2-3 3-1 3-2 3-3 d1s 0.966 1.012 1.190 1.370 1.556 1.307 1.608 1.526 1.342 d1m 0.412 0.566 0.446 0.598 0.643 0.429 0.806 0.530 0.718 D1s 2.438 2.503 2.442 2.373 2.544 2.287 2.591 2.341 2.447 D1m 2.382 2.472 2.431 2.362 2.563 2.328 2.616 2.375 2.450 d2s 0.706 0.665 0.684 0.623 0.720 0.606 0.964 0.933 0.960 D2s 2.619 2.694 2.690 2.658 2.815 2.577 2.829 2.604 2.615 d3s 1.293 0.916 0.981 1.276 0.951 0.949 1.393 1.455 1.409 d3m 1.259 0.916 0.981 0.984 0.951 0.949 2.180 1.455 2.195 D3s 2.583 2.754 2.750 2.643 2.875 2.637 2.783 2.664 2.410 D3m 2.553 2.754 2.750 2.639 2.875 2.637 2.682 2.664 2.585 d0s 2.774 2.345 2.610 3.156 2.733 2.427 2.762 2.508 2.716 D0m 3.705 3.756 3.525 4.126 3.637 3.419 3.696 3.571 3.530 CP1 0.243 0.269 0.324 0.465 0.434 0.411 0.346 0.289 0.186 CP3 0.274 0.022 0.022 0.287 0.022 0.022 0.617 0.022 0.691 EP01 0.894 0.816 0.843 0.836 0.808 0.683 0.556 0.494 0.636 EP12 0.369 0.352 0.349 0.331 0.368 0.320 0.439 0.372 0.456 EP23 0.303 0.256 0.436 0.289 0.444 0.332 0.326 0.444 0.280 f1 -1.82 -1.82 -1.82 -2.16 -2.16 -2.16 130.23 130.23 130.23 f2 0.85 0.85 0.85 -0.98 -0.98 -0.98 1.13 1.13 1.13 f3 23.06 23.06 23.06 0.65 0.65 0.65 -3.16 -3.16 -3.16 f4 2.78 2.78 2.78 5.11 5.11 5.11 2.00 2.00 2.00 f34 1.95 1.95 1.95 0.53 0.53 0.53 2.87 2.87 2.87

[0145] Table 9

[0146] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0147] 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.

[0148] 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.

[0149] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An optical lens, characterized in that, The optical lens can be used for near-infrared imaging. The optical lens includes a lens barrel and a lens group and a spacer element group located within the lens barrel. The lens group consists of four lenses, including a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the extension direction of the optical axis. The spacer group includes at least a first spacer element, which is located between the first lens and the second lens and contacts a portion of the image-side surface of the first lens; The minimum distance EP01 between the object-side end face of the lens barrel and the first spacer element in the extension direction of the optical axis, the maximum thickness CP1 of the first spacer element, and the air gap T12 between the first lens and the second lens on the optical axis satisfy the following: 0.56≤EP01 / (T12+CP1)≤1.01; The radius of curvature R1 of the object side surface of the first lens, the refractive index N1 of the first lens, and the inner diameter d1s of the object side surface of the first spacer element satisfy the following condition: -4.44≤R1*N1 / d1s≤-1.

71.

2. The optical lens according to claim 1, characterized in that, The radius of curvature R2 of the image side of the first lens, the outer diameter D1s of the object side of the first spacer element, and the inner diameter d1s of the object side of the first spacer element satisfy the following: 1.06≤|R2| / (D1s-d1s)≤3.

74.

3. The optical lens according to claim 1, characterized in that, The radius of curvature R3 of the object side of the second lens and the inner diameter d1m of the image side of the first spacer element satisfy the following condition: -2.65≤R3 / d1m≤-1.

53.

4. The optical lens according to claim 1, characterized in that, The inner diameter d0s of the object-side end face of the lens barrel and the radius of curvature R1 of the object-side surface of the first lens satisfy the following condition: -0.9≤d0s / R1≤-0.

35.

5. The optical lens according to claim 1, characterized in that, The outer diameter D0m of the image-side end face of the lens barrel and the radius of curvature R8 of the image-side surface of the fourth lens satisfy the following condition: 2.65≤D0m / R8≤7.

52.

6. The optical lens according to any one of claims 1 to 5, characterized in that, The spacer element group further includes a second spacer element, which is located between the second lens and the third lens and contacts a portion of the image side surface of the second lens. The radius of curvature R4 of the image side surface of the second lens, the outer diameter D1m of the image side surface of the first spacer element, and the outer diameter D2s of the object side surface of the second spacer element satisfy the following condition: 1.34≤|R4| / (D2s-D1m)≤7.

89.

7. The optical lens according to any one of claims 1 to 5, characterized in that, The spacer group further includes a second spacer element, which is located between the second lens and the third lens and contacts a portion of the image side of the second lens. The minimum distance EP12 between the first spacer element and the second spacer element in the extension direction of the optical axis and the air gap T12 between the first lens and the second lens on the optical axis satisfy: 0.4≤EP12 / T12≤1.

03.

8. The optical lens according to any one of claims 1 to 5, characterized in that, The spacer element group further includes a third spacer element, which is located between the third lens and the fourth lens and contacts a portion of the image side of the third lens. The radius of curvature R5 of the object side of the third lens, the refractive index N3 of the third lens, and the outer diameter D3s of the object side of the third spacer element satisfy the following: -0.26≤R5*N3 / D3s≤0.

31.

9. The optical lens according to any one of claims 1 to 5, characterized in that, The spacer group further includes a third spacer element, which is located between the third lens and the fourth lens and contacts a portion of the image-side surface of the third lens. The radius of curvature R6 of the image-side surface of the third lens and the inner diameter d3s of the object-side surface of the third spacer element satisfy the following: -0.7≤R6 / d3s≤-0.

38.

10. The optical lens according to any one of claims 1 to 5, characterized in that, The spacer group further includes a third spacer element, which is located between the third lens and the fourth lens and contacts a portion of the image-side surface of the third lens. The outer diameter D3m of the image-side surface of the third spacer element, the inner diameter d3m of the image-side surface of the third spacer element, and the radius of curvature R7 of the object-side surface of the fourth lens satisfy the following: 0.28≤R7 / (D3m-d3m)≤1.

84.

11. The optical lens according to any one of claims 1 to 5, characterized in that, The spacer element group further includes a second spacer element and a third spacer element. The second spacer element is located between the second lens and the third lens and contacts a portion of the image-side surface of the second lens. The third spacer element is located between the third lens and the fourth lens and contacts a portion of the image-side surface of the third lens. The minimum distance EP23 between the second spacer element and the third spacer element in the extension direction of the optical axis and the effective focal length f4 of the fourth lens satisfy the following condition: 4.51≤f4 / EP23≤17.

67.

12. The optical lens according to any one of claims 1 to 5, characterized in that, The spacer element group further includes a second spacer element and a third spacer element. The second spacer element is located between the second lens and the third lens and contacts a portion of the image-side surface of the second lens. The third spacer element is located between the third lens and the fourth lens and contacts a portion of the image-side surface of the third lens. The minimum distance EP23 between the second spacer element and the third spacer element in the extension direction of the optical axis, the combined focal length f34 of the third lens and the fourth lens, and the air gap T34 between the third lens and the fourth lens on the optical axis satisfy the following: 1.09≤f34 / (EP23+T34)≤8.

83.

13. The optical lens according to any one of claims 1 to 5, characterized in that, The fourth lens has positive optical power.

14. The optical lens according to any one of claims 1 to 5, characterized in that, The optical lens satisfies at least one of the following: The object-side surface of the first lens is concave; The object-side surface of the second lens is concave. The image-side surface of the third lens is convex. The object-side surface of the fourth lens is convex. The image-side surface of the fourth lens is concave.

Images