Optical lens

Abstract

The invention 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 invention, the problem of serious stray light caused by reduction of aberration in an optical lens in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical imaging equipment, and in particular to an optical lens. Background Art

[0002] With the development of science and technology, more and more electronic products have camera functions, and users have gradually increased their requirements for optical lenses installed in electronic products, requiring optical lenses to have high definition. In order to improve the imaging quality of optical lenses, the imaging quality of optical lenses can be improved by improving the aberration of optical lenses. However, in this process, more stray light may be reflected between the lenses of the optical lens, resulting in serious stray light.

[0003] That is to say, in the prior art, the optical lens has the problem of causing serious stray light in order to reduce aberration. Summary of the invention

[0004] The main purpose of the present invention is to provide an optical lens to solve the problem of serious stray light caused by reducing aberration in the optical lens in the prior art.

[0005] To achieve the above-mentioned purpose, according to one aspect of the present invention, an optical lens is provided, which can be used for imaging in the near-infrared band. The optical lens comprises a lens barrel, a lens group and a spacer element group located in the lens barrel, wherein the lens group consists of four lenses, and the lens group comprises a first lens, a second lens, a third lens and a fourth lens arranged in sequence along the extension direction of the optical axis; the spacer element group comprises at least a first spacer element, and the first spacer element is located between the first lens and the second lens and contacts a part of the image side surface of the first lens; the minimum distance EP01 between the object side end surface 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 conditions: 0.56≤EP01 / (T12+CP1)≤1.01; the curvature radius 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 conditions: -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 imaging in the near-infrared band. The optical lens includes a lens barrel, a lens group and a spacer element group located in the lens barrel, the lens group consists of four lenses, and the lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence along the extension direction of the optical axis; the spacer element group includes at least a third spacer element, and 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 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: 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 curvature radius R7 of the object side surface of the fourth lens satisfy: 0.28≤R7 / (D3m-d3m)≤1.84.

[0007] According to another aspect of the present invention, an optical lens is provided. The optical lens can be used for near-infrared band imaging. The optical lens includes a lens barrel and a lens group and a spacer element group located in the lens barrel. The lens group consists of four lenses. The lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence 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. The third spacing 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 inner diameter d1m of the image side surface of the first spacing element, the inner diameter d3s of the object side surface of the third spacing element, the curvature radius R3 of the object side surface of the second lens, and the curvature radius R6 of the image side surface of the third lens satisfy: -3.03≤R3 / d1m+R6 / d3s≤-2.14; the curvature radius 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 spacing element satisfy: -0.8≤R4*N2 / d2s≤5.32.

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

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

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

[0011] Furthermore, an outer diameter D0m of the image-side end surface of the lens barrel and a curvature radius R8 of the image-side surface of the fourth lens satisfy the relationship: 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 curvature radius 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: 1.34≤|R4| / (D2s-D1m)≤7.89.

[0013] 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 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.

[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 surface of the third lens. The curvature radius 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: -0.26≤R5*N3 / D3s≤0.31.

[0015] 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 surface of the third lens. The curvature radius 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: -0.7≤R6 / d3s≤-0.38.

[0016] 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 surface of the third lens, and 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 curvature radius R7 of the object side surface of the fourth lens satisfy: 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, and 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: 4.51≤f4 / EP23≤17.67.

[0018] Further, 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, and 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: 1.09≤f34 / (EP23+T34)≤8.83.

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

[0020] Further, 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 fourth lens is concave.

[0021] By applying the technical solution of the present invention, an optical lens can be used for near-infrared band imaging. The optical lens includes a lens barrel, a lens group and a spacer element group located in the lens barrel, the lens group consists of four lenses, and the lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence along the extension direction of the optical axis; the spacer element group includes at least a first spacer element, the first spacer element is located between the first lens and the second lens and contacts a part 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: 0.56≤EP01 / (T12+CP1)≤1.01; the curvature radius 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: -4.44≤R1*N1 / d1s≤-1.71.

[0022] The optical lens of the present application is composed 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 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 conditions: 0.56≤EP01 / (T12+CP1)≤1.01, the range of the air gap between the first lens and the second lens can be limited, which is beneficial to controlling the change of 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 easily causes non-imaging light to generate reflected stray light in the area and position between the first lens and the second lens, resulting in serious stray light. In order to reduce the generation of such stray light, the present application constrains R1*N1 / d1s within a reasonable range to adjust the deflection angle of the light when it passes through the first lens, to ensure that the light will not be deflected at a large angle, to avoid the light being deflected to areas outside the effective diameter to generate reflected stray light, and to ensure that the first spacing element blocks the non-effective diameter area of ​​the first lens, thereby further reducing the generation of stray light and ensuring the imaging quality of the optical lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 A dimensioning diagram of an optical lens of an optional embodiment of the present invention is shown;

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

[0026] Figure 3 A schematic structural diagram of an optical lens according to Embodiment 1-2 of the present invention is shown;

[0027] Figure 4 A schematic diagram showing the structure of an optical lens according to embodiments 1 to 3 of the present invention is shown;

[0028] Figures 5 to 8 The axial chromatic aberration, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical lens of the first embodiment of the present invention are respectively shown;

[0029] Fig. 9 A schematic structural diagram of an optical lens according to Embodiment 2-1 of the present invention is shown;

[0030] Fig.10 A schematic structural diagram of an optical lens according to Embodiment 2-2 of the present invention is shown;

[0031] Fig.11 A schematic structural diagram of an optical lens according to Embodiment 2-3 of the present invention is shown;

[0032] Figures 12 to 15 The axial chromatic aberration, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical lens of the second embodiment of the present invention are respectively shown;

[0033] Fig.16 A schematic structural diagram of an optical lens according to Embodiment 3-1 of the present invention is shown;

[0034] Fig.17 A schematic structural diagram of an optical lens according to Embodiment 3-2 of the present invention is shown;

[0035] Fig.18 A schematic structural diagram of an optical lens according to Embodiment 3-3 of the present invention is shown;

[0036] Figures 19 to 22 The axial chromatic aberration, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical lens of the third embodiment of the present invention are respectively shown;

[0037] Fig.23 A light path diagram of partial light rays in an optical lens of an optional embodiment of the present invention is shown;

[0038] Fig.24 Shows Fig.23 The stray light spot diagram of the optical lens;

[0039] Fig.25 A light path diagram of some light rays in an optical lens in an example is shown;

[0040] Fig.26 Shows Fig.25 The stray light spot diagram of the optical lens;

[0041] Fig. 27 A light path diagram of some light rays in an optical lens in an example is shown;

[0042] Fig.28 Shows Fig. 27 The stray light spot diagram of the optical lens.

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

[0044] E1, first lens; P1, first spacing element; P1b, first auxiliary spacing element; E2, second lens; P2, second spacing element; E3, third lens; P3, third spacing element; P3b, third auxiliary spacing 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 DESCRIPTION

[0045] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0046] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0047] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0048] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0049] In the 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 shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0050] In this article, the paraxial area refers to the area near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial area; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial area. The judgment of the surface shape in the paraxial area can be based on the judgment method of the general knowledge in this field, and the positive and negative R value (R refers to the radius of curvature of the paraxial area, usually refers to the R value on the lens database (lens data) in the optical software) is used to judge the convexity and concavity. For the object side, when the R value is positive, it is judged as a convex surface, and when the R value is negative, it is judged as a concave surface; for the image side, when the R value is positive, it is judged as a concave surface, and when the R value is negative, it is judged as a convex surface. In the present application, the left side is the object side and the right side is the image side.

[0051] In order to solve the problem of serious stray light caused by reducing aberration in optical lenses in the prior art, the present invention provides an optical lens.

[0052] like Figures 1 to 22 As shown, the optical lens can be used for near-infrared band imaging, and the optical lens includes a lens barrel and a lens group and a spacer element group located in the lens barrel, the lens group consists of four lenses, and the lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence along the extension direction of the optical axis; the spacer element group includes at least a first spacer element, and the first spacer element is located between the first lens and the second lens and contacts a part 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: 0.56≤EP01 / (T12+CP1)≤1.01; the curvature radius 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: -4.44≤R1*N1 / d1s≤-1.71.

[0053] The optical lens of the present application is composed 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 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 conditions: 0.56≤EP01 / (T12+CP1)≤1.01, the range of the air gap between the first lens and the second lens can be limited, which is beneficial to controlling the change of 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 easily causes non-imaging light to generate reflected stray light in the area and position between the first lens and the second lens, resulting in serious stray light. In order to reduce the generation of such stray light, the present application constrains R1*N1 / d1s within a reasonable range to adjust the deflection angle of the light when it passes through the first lens, to ensure that the light will not be deflected at a large angle, to avoid the light being deflected to areas outside the effective diameter to generate reflected stray light, and to ensure that the first spacing element blocks the non-effective diameter area of ​​the first lens, thereby further reducing the generation of stray light and ensuring the imaging quality of the optical lens.

[0054] In addition, refer to Table 1 and Figure 23 to Figure 28 As shown, Fig.23 The diagram shows a partial optical path diagram of the optical lens when EP01 / (T12+CP1)=0.87 and R1*N1 / d1s=-3.61. Fig.24 Shows Fig.23 The stray light spot diagram of the optical lens. Fig.25 The diagram shows a partial optical path diagram of the optical lens when EP01 / (T12+CP1)=0.87 and R1*N1 / d1s=-4.8. Fig.26 Shows Fig.25 The stray light spot diagram of the optical lens. Fig. 27 It shows a partial optical path schematic diagram of the optical lens when EP01 / (T12+CP1)=0.87 and R1*N1 / d1s=-1.2. Fig.28 Shows Fig. 27 The stray light spot diagram of the optical lens.

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

[0056]

[0057] Table 1

[0058] It should be noted that the present application limits R1*N1 / d1s within a reasonable range, optimizes the relationship between the first spacing element and the first lens, so as to improve the stray light generated in the effective diameter area of ​​the first lens, and solves the stray light problem caused when EP01 / (T12+CP1) is in the range of 0.56 to 1.01. When R1*N1 / d1s meets the above range, the purpose of improving stray light can be achieved, and it does not depend on the focal length of the lens and the surface shape of the lens. The focal length and surface shape of the lens are further optimization of the optical lens on this basis. Each lens can be positive or negative according to the actual design requirements of the optical system, and the surface shape of each lens can be convex or concave according to the design requirements of the optical system. The optical system meets: 2.6≤d0m / |R8|≤8.67; -4.44≤R1*N1 / d1s≤-1.71, and 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 focal length, and by constraining the focal length of the fourth lens, it is beneficial for the light to converge after being emitted by the fourth lens, so as to adapt to the chip at the imaging surface. For 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; the image side surface of the fourth lens is concave, and by reasonably constraining the surface shape of each lens, it is beneficial to reasonably constrain the trend of light, ensure a smooth transition of light, and help correct aberrations. The optical lens can be simulated by software and / or tools such as ZEMAX and CODEV. Preferably, the optical lens can be simulated by CODEV. In the process of simulation using software and / or tools such as the above, the surface shape of each lens can be simulated and appropriately adjusted according to the surface shape of the software and / or tools used.

[0060] In some optional embodiments, the curvature radius 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: 1.06≤|R2| / (D1s-d1s)≤3.74. By constraining |R2| / (D1s-d1s) within a reasonable range, not only can the supporting width of the first spacer element and the first lens be guaranteed, and the stability of the first lens supporting can be guaranteed, but also the angle of the light emitted from the image side surface of the first lens can be controlled, and the imaging light can be smoothly incident on the second lens. Not only can the light emitted by the first lens with a large angle be deflected, but the first spacer element can also absorb the stray light generated at the edge of the effective diameter of the first lens, which is conducive to further reducing the stray light.

[0061] In some optional embodiments, the curvature radius R3 of the object side surface of the second lens and the inner diameter d1m of the image side surface of the first spacing element satisfy: -2.65≤R3 / d1m≤-1.53. By constraining R3 / d1m within a reasonable range, the image side surface of the first spacing element can shield the non-effective diameter area of ​​the object side surface of the second lens, and at the same time control the divergence angle of the light after passing through the object side surface of the second lens, so as to reduce the stray light generated in the non-effective diameter area 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 curvature radius R1 of the object side face of the first lens satisfy: -0.9≤d0s / R1≤-0.35. By constraining d0s / R1 within a reasonable range, it is beneficial to control the aperture of the object side end face of the lens barrel, avoid the lens barrel blocking the imaging light, ensure the imaging brightness of the optical lens, and control the degree of deflection of the light facing the object side of the first lens, which is beneficial for large-angle light to enter the optical lens, increase the field of view of the optical lens, improve the relative brightness, and improve the imaging quality of the optical lens. It can also prevent the first lens from protruding from the lens barrel, avoid the first lens from being damaged, and reduce the appearance of poor appearance.

[0063] In some optional embodiments, the outer diameter D0m of the image side end surface of the lens barrel and the curvature radius R8 of the image side surface of the fourth lens satisfy: 2.65≤D0m / R8≤7.52. By constraining D0m / R8 within a reasonable range, it is beneficial to control the exit angle of the light through the fourth lens, to ensure the convergence of the light on the imaging surface, and then to facilitate the adaptation of the exit angle of the optical lens to the chip, while limiting the size of the lens barrel, which is beneficial to 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, 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, and the curvature radius 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: 1.34≤|R4| / (D2s-D1m)≤7.89. By constraining |R4| / (D2s-D1m) within a reasonable range, it is helpful 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, ensure the bearing area of ​​the first spacer element and the second spacer element on the second lens, reduce the occurrence of uneven force on the object side surface and the image side surface of the second lens, ensure the stability of the second lens assembly while controlling the curvature radius of the image side surface of the second lens, ensure that the light is smoothly emitted from the second lens, and reduce the risk of the first spacer element and the second spacer element blocking the light passing through the second lens.

[0065] In some optional embodiments, the spacer element group further includes a second 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, and 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 distance T12 between the first lens and the second lens on the optical axis satisfy: 0.4≤EP12 / T12≤1.03. Constraining EP12 / T12 within a reasonable range can not only constrain the relative positional relationship between the first spacer element and the second spacer element, ensuring the stability of the support for the second lens, but also constrain the edge thickness of the second lens to ensure the matching accuracy of the second lens and the lens barrel, while avoiding interference between the first lens and the second lens, reducing the sensitivity of the second lens, and helping to improve the stability of the second lens assembly, thereby helping to ensure 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, which is located between the third lens and the fourth lens and contacts a portion of the image side surface of the third lens, and the curvature radius 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: -0.26≤R5*N3 / D3s≤0.31. Restricting R5*N3 / D3s within a reasonable range is conducive to ensuring the supporting width of the third spacer element on the third lens to ensure the stability of the third lens group, and is also conducive to improving the surface shape of the object side surface of the third lens, and can control the deflection angle of the light when the light passes through the object side surface of the third lens, which is conducive to reducing the energy of the ghost image spot reflected by the effective diameter of the third lens, and is conducive to improving the imaging quality. In addition, the third spacer element can also absorb part of the stray light emitted by the third lens to reduce the stray light.

[0067] In some optional embodiments, 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 surface of the third lens, and the curvature radius 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: -0.7≤R6 / d3s≤-0.38. R6 / d3s is constrained within a reasonable range, and the curvature radius of the image side surface of the third lens and the blocking range of the image side surface of the third lens by the third spacer element are limited, so as to ensure that the imaging light passes smoothly through the inner diameter of the third spacer element after being emitted by the third lens, and will not be blocked by the third spacer element. At the same time, it can also ensure that the stray light path at the edge of the effective diameter of the image side surface of the third lens is intercepted by the third spacer, so as to ensure the imaging quality of the lens.

[0068] In some optional embodiments, the spacer element group further includes a third spacer element, 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, and 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 curvature radius R7 of the object side surface of the fourth lens satisfy: 0.28≤R7 / (D3m-d3m)≤1.84. Restricting R7 / (D3m-d3m) within a reasonable range can ensure the adsorption space of the third spacer element, which is conducive to improving the stability of the optical lens assembly and ensuring the feasibility of the assembly process. At the same time, it can ensure that the imaging light emitted by the third lens is smoothly converged to the rear optical system through the object side of the fourth lens, ensuring the accurate transmission path of the light.

[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 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, and 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: 4.51≤f4 / EP23≤17.67. Restricting f4 / EP23 within a reasonable range is conducive to controlling the deflection angle of light when passing through the fourth lens, ensuring that the light is in a convergent state when emitted through the fourth lens, thereby limiting the incident angle of the light emitted by the fourth lens to the chip on the imaging surface, and at the same time limiting the bearing force of the structure between the second spacer element and the third spacer element on the fourth lens to ensure the bearing stability of the fourth lens. At the same time, it can also ensure that the edge thickness of the third lens is within a reasonable range, ensuring the bearing stability of the third lens and the 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 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, and 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: 1.09≤f34 / (EP23+T34)≤8.83. By constraining f34 / (EP23+T34) within a reasonable range, the bearing force provided by the structure between the second spacer element and the third spacer element can be limited, and the manufacturing tolerance of the edge thickness of the lens during the assembly process, as well as factors such as the air gap and the surface shape, can be avoided to affect the optical performance after assembly, and the convergence effect of light after passing through the third lens and the fourth lens can be ensured, thereby improving 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 imaging in the near-infrared band. The optical lens includes a lens barrel, a lens group and a spacer element group located in the lens barrel, the lens group consists of four lenses, and the lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence along the extension direction of the optical axis; the spacer element group includes at least a third spacer element, and 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 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: 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 curvature radius R7 of the object side surface of the fourth lens satisfy: 0.28≤R7 / (D3m-d3m)≤1.84.

[0072] The optical lens of the present application is composed of a lens barrel, four lenses and at least one spacer element. When 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: 0.07≤T34 / CP3≤2.05, the gap between the third lens and the fourth lens can be constrained, and the change of the air gap during the assembly process can be reduced to affect the optical performance of the optical lens. However, during the assembly process, the fourth lens is prone to interfere with the third lens, increasing the difficulty of assembly. The present application constrains R7 / (D3m-d3m) within a reasonable range, which can ensure the adsorption space between the fourth lens and the third spacer element, facilitate the adsorption of the fourth lens and the third spacer element, reduce the difficulty of assembly, improve the stability of assembly, and control the curvature radius of the object side of the fourth lens at the same time. While ensuring the imaging performance, the interference of the fourth lens on the third lens is reduced, further reducing the difficulty of assembly.

[0073] Of course, this embodiment may also include other parameter formulas in the above embodiment, which will not be described one by one here.

[0074] According to another aspect of the present invention, an optical lens is provided. The optical lens can be used for near-infrared band imaging. The optical lens includes a lens barrel and a lens group and a spacer element group located in the lens barrel. The lens group consists of four lenses. The lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence 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. The third spacing 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 inner diameter d1m of the image side surface of the first spacing element, the inner diameter d3s of the object side surface of the third spacing element, the curvature radius R3 of the object side surface of the second lens, and the curvature radius R6 of the image side surface of the third lens satisfy: -3.03≤R3 / d1m+R6 / d3s≤-2.14; the curvature radius 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 spacing element satisfy: -0.8≤R4*N2 / d2s≤5.32.

[0075] The optical lens of the present application is composed 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 curvature radius R3 of the object side surface of the second lens, and the curvature radius R6 of the image side surface of the third lens satisfy: -3.03≤R3 / d1m+R6 / d3s≤-2.14, it is beneficial to diffuse the light entering the rear optical system through the first lens, so as to ensure the field angle of the optical lens. However, in the process of light diffusion from the object side surface of the second lens to the image side surface of the third lens, it is easy to generate light with a large angle deflection, causing serious stray light. In order to reduce the generation of such stray light, the present application constrains R4*N2 / d2s within a reasonable range to adjust the deflection angle of the light when it is emitted through the image side of the second lens, reduce the light deflected at a large angle, avoid the light being deflected to the area outside the effective diameter to generate reflected stray light, ensure that the second spacing element blocks the non-effective diameter area of ​​the second lens, further reduce the generation of stray light, and thus ensure the imaging quality of the optical lens.

[0076] Of course, this embodiment may also include other parameter formulas in the above embodiment, which will not be described one by one here.

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

[0078] In some optional embodiments, at least one trimming spacer element may be included in the plurality of spacer elements. The outer circumference of the trimming spacer element may have a trimming portion and a non-trimming portion, and the outer diameter of the trimming portion of the trimming spacer element is smaller than the outer diameter of the non-trimming portion of the trimming spacer element, and the outer diameter of the spacer element generally refers to the maximum outer diameter of the non-trimmed portion.

[0079] Optionally, the optical lens may further include a protective glass for protecting a photosensitive element located on the imaging surface.

[0080] It should be noted that each lens is composed of a central optical effective diameter area and an edge structure area, and the edge structure area is located on the outer peripheral side of the central optical effective diameter area and is arranged around the circumference of the central optical effective diameter area. The central optical effective diameter area is used for the passage of imaging light, while the edge structure area is not used for the passage of imaging light, and is used to abut against the lens barrel or adjacent lenses or adjacent spacing elements. The edge structure area is also called a non-effective diameter area.

[0081] The optical lens in the present application may use multiple lenses, such as the four lenses mentioned above. In the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. The characteristics of an aspherical lens are: the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After using an aspherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality.

[0082] However, those skilled in the art should understand that, without departing from the technical solution claimed in the present application, the number of lenses constituting the optical lens can be changed to obtain the various results and advantages described in this specification. For example, although four lenses are 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 of the dimension marking of an optical lens of the present application is shown. Figure 1 Parameters such as d1s, d1m, D1s, D1m, D2s, d3s, d3m, D3s, D3m, d0s, D0m, CP1, EP01, EP12, and EP23 are indicated in the figure to clearly and intuitively understand the meaning of the parameters. In order to facilitate the description of the optical lens and the surface shape of the specific lens, these parameters will no longer be reflected in the drawings when describing the specific embodiments later.

[0084] The following further describes examples of specific surface shapes and parameters of the optical lens applicable to the above-mentioned embodiments with reference to the accompanying drawings.

[0085] It should be noted that in the following embodiment 1, there are three examples, namely, embodiment 1-1, embodiment 1-2, and embodiment 1-3; in embodiment 2, there are three examples, namely, embodiment 2-1, embodiment 2-2, and embodiment 2-3; and in embodiment 3, there are three examples, namely, embodiment 3-1, embodiment 3-2, and embodiment 3-3. In the two examples of the same embodiment, the parameters such as the radius of curvature, the center thickness, the spacing distance between the lenses, and the coefficients of the higher-order terms of the optical lenses of the first to fourth lenses are the same, but the parameters such as the thickness, the inner diameter, and the outer diameter of the lens barrel, the first spacing element, the second spacing element, and the third spacing element, as well as the shapes of some lenses are different. In other words, the main structures for imaging are the same, but the auxiliary structures for imaging are different.

[0086] It should be noted that any of the following embodiments 1 to 3 are applicable to all implementation methods of the present application.

[0087] Embodiment 1

[0088] like Figures 2 to 5 As shown, the optical lens of embodiment 1 is described. Figure 2 The structure diagram of the optical lens of Example 1-1 is shown. Figure 3 The structure diagram of the optical lens of Example 1-2 is shown. Figure 4 The schematic diagrams of the structures of the optical lenses of Examples 1-3 are 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, which are arranged in sequence from the object side to the image side.

[0090] like Figure 2 1-1, it is the structural representation of the optical lens of embodiment 1-1. In this example, the optical lens also includes the third auxiliary spacing element P3b. The object side surface S1 of the first lens partially abuts with the lens barrel. The object side surface and the image side surface of the first spacing element P1 partially abut with the image side surface S2 of the first lens and the object side surface of the first auxiliary spacing element, and the image side surface of the first auxiliary spacing element P1b partially abuts with the object side surface S3 of the second lens. The object side surface and the image side surface of the second spacing element partially abut with 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 the image side surface of the third spacing element partially abut with the image side surface S6 of the third lens and the object side surface of the third auxiliary spacing element, and the image side surface of the third auxiliary spacing element partially abuts with 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 FIG. 1 is a schematic diagram of the structure of the optical lens of Example 1-2. In this example, the supporting and abutting manner of each spacing element is the same as that of Example 1-1, and the relevant description in Example 1-1 may be referred to, and will not be repeated here.

[0092] like Figure 4 As shown, it is a schematic diagram of the structure of the optical lens of Example 1-3. In this example, the optical lens does not have a third auxiliary spacing element P3b, and the image side surface of the third spacing element is partially abutted against the object side surface S7 of the fourth lens. The supporting and abutting methods of other spacing elements are the same as those in Example 1-1. Please refer to the relevant description in Example 1-1 and will not be repeated here.

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

[0094] In the first embodiment, the object side surface S1 of the first lens is a concave surface, and the image side surface S2 of the first lens is a concave surface. The object side surface S3 of the second lens is a concave surface, and the image side surface S4 of the second lens is a convex surface. The object side surface S5 of the third lens is a concave surface, and the image side surface S6 of the third lens is a convex surface. The object side surface S7 of the fourth lens is a convex surface, and the image side surface S8 of the fourth lens is a concave surface. S9 and S10 in the following table 2 can be the surface of a filter or a protective glass, while S11 is an imaging surface, and STO is a stop, which is not shown in the figure.

[0095] Table 2 shows the basic structural parameters of the optical lens of Example 1, wherein the units of the radius of curvature and thickness / distance are all millimeters.

[0096]

[0097] Table 2

[0098] In the first embodiment, the object side surface and the image side surface of the first lens E1 to the fourth lens E4 are all aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0099]

[0100] Wherein, x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c=1 / R, that is, the paraxial curvature c is the reciprocal of the curvature radius R in the above Table 1; k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. The following Table 3 lists the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, and A28 that can be used for each aspheric mirror surface S1-S8 in Example 1.

[0101]

[0102]

[0103] Table 3

[0104] Figure 5 The axial chromatic aberration curve of the optical lens of the first embodiment is shown, which indicates the deviation of the focusing point of light rays of different wavelengths after passing through the optical lens. Figure 6 The astigmatism curve of the optical lens of Example 1 is shown, which represents the meridional image curvature and the sagittal image curvature. Figure 7 The distortion curve of the optical lens of the first embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. Figure 8 The magnification chromatic aberration curve of the optical lens of Example 1 is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the lens.

[0105] according to Figures 5 to 8 It can be seen that the optical lens provided in the first embodiment can achieve good imaging quality.

[0106] Embodiment 2

[0107] like Figures 9 to 15 As shown, the optical lens of the second embodiment is described. Fig. 9 The structure diagram of the optical lens of Example 2-1 is shown. Fig.10 FIG. 2 shows a schematic structural diagram of an optical lens of Example 2-2. Fig.11 A schematic structural diagram of the optical lens of Example 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, which are arranged in sequence from the object side to the image side.

[0109] like Fig. 9, it is a structural schematic diagram of the optical lens of embodiment 2-1. In this example, the optical lens also includes the third auxiliary spacing element P3b. The object side surface S1 of the first lens partially abuts against the lens barrel. The object side surface of the first spacing element P1 partially abuts against the image side surface S2 of the first lens. The object side surface and image side surface of the first auxiliary spacing element P1b partially abut against the image side surface S3 of the second lens of the first spacing element respectively. The object side surface and image side surface of the second spacing element partially 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 spacing element partially abut against the image side surface S6 of the third lens and the object side surface of the third auxiliary spacing element respectively, the image side surface of the third auxiliary spacing element partially 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 Fig.10 FIG. 2 is a schematic diagram of the structure of the optical lens of Example 2-2. In this example, the optical lens does not have a third auxiliary spacer element P3b, the image side surface of the third spacer element partially abuts against the object side surface S7 of the fourth lens, and the abutting manner of other spacer elements is the same as that of Example 1-1, and reference may be made to the relevant description in Example 1-1, which will not be repeated here.

[0111] like Fig.11 , which is a schematic diagram of the structure of the optical lens of Example 2-3. In this example, the supporting and abutting manner of each spacing element is the same as that of Example 1-1. Please refer to the relevant description in Example 1-1 and no further details will be given here.

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

[0113] In the second embodiment, the object side S1 of the first lens is a concave surface, and the image side S2 of the first lens is a concave surface. The object side S3 of the second lens is a concave surface, and the image side S4 of the second lens is a concave surface. The object side S5 of the third lens is a convex surface, and the image side S6 of the third lens is a convex surface. The object side S7 of the fourth lens is a convex surface, and the image side S8 of the fourth lens is a concave surface. S9 and S10 in the following table 4 can be the surface of a filter or a protective glass, while S11 is an imaging surface, and STO is a stop, which is not shown in the figure.

[0114] Table 4 shows the basic structural parameters of the optical lens of Example 2, wherein the units of the radius of curvature and thickness / distance are all millimeters.

[0115]

[0116] Table 4

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

[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] Fig.12 The axial chromatic aberration curve of the optical lens of the second embodiment is shown, which indicates the deviation of the focusing point of light rays of different wavelengths after passing through the optical lens. Fig.13 The astigmatism curve of the optical lens of Example 2 is shown, which represents the meridional image curvature and the sagittal image curvature. Fig.14 The distortion curve of the optical lens of the second embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. Fig.15 The magnification chromatic aberration curve of the optical lens of Example 2 is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the lens.

[0121] according to Figures 12 to 15 It can be seen that the optical lens provided in the second embodiment can achieve good imaging quality.

[0122] Embodiment 3

[0123] like Figures 16 to 22 As shown, the optical lens of embodiment 3 is described. Fig.16 The structure diagram of the optical lens of Example 3-1 is shown. Fig.17 FIG. 3 is a schematic diagram showing the structure of the optical lens of Example 3-2. Fig.18 A schematic structural diagram of the optical lens of Example 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, which are arranged in sequence from the object side to the image side.

[0125] like Fig.16As shown, it is the structural schematic diagram of the optical lens of embodiment 3-1. In this example, the object side surface S1 of the first lens partially abuts with the lens barrel. The object side surface and the image side surface of the first spacing element P1 partially abut with the image side surface S2 of the first lens and the object side surface of the first auxiliary spacing element respectively. The image side surface of the first auxiliary spacing element partially abuts with the object side surface S3 of the second lens. The object side surface and the image side surface of the second spacing element partially abut with 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 the image side surface of the third spacing element partially abut with the image side surface S6 of the third lens and the object side surface of the third auxiliary spacing element respectively. The image side surface of the third auxiliary spacing element partially abuts with 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 Fig.17 The structure diagram of the optical lens of Example 3-2 is shown in FIG. The supporting and abutting manner of each spacing element is the same as that of Example 3-1, and the relevant description in Example 3-1 may be referred to, and will not be repeated here.

[0127] like Fig.18 The structure diagram of the optical lens of Example 3-3 is shown in FIG. The supporting and abutting manner of each spacing element is the same as that of Example 3-1, and the relevant description in Example 3-1 may be referred to, and will not be repeated here.

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

[0129] In embodiment three, the object side surface S1 of the first lens is a concave surface, and the image side surface S2 of the first lens is a convex surface. The object side surface S3 of the second lens is a concave surface, and the image side surface S4 of the second lens is a convex surface. The object side surface S5 of the third lens is a concave surface, and the image side surface S6 of the third lens is a convex surface. The object side surface S7 of the fourth lens is a convex surface, and the image side surface S8 of the fourth lens is a concave surface. S9 and S10 in the following table 6 can be the surface of a filter or a protective glass, while S11 is an imaging surface, and STO is a stop, which is not shown in the figure.

[0130] Table 6 shows the basic structural parameters of the optical lens of Example 3, wherein the units of the radius of curvature and thickness / distance are all millimeters.

[0131]

[0132]

[0133] Table 6

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

[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] Fig.19 The axial chromatic aberration curve of the optical lens of the third embodiment is shown, which indicates the deviation of the focusing point of light rays of different wavelengths after passing through the optical lens. Fig. 20 The astigmatism curve of the optical lens of Example 3 is shown, which represents the meridional image curvature and the sagittal image curvature. Fig.21 The distortion curve of the optical lens of the third embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. Fig. 22 The magnification chromatic aberration curve of the optical lens of Example 3 is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the lens.

[0138] according to Figures 19 to 22 It can be seen that the optical lens provided in the third embodiment can achieve good imaging quality.

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

[0140]

[0141]

[0142] Table 8

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

[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 above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0147] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0148] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0149] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An optical lens, characterized in that: The optical lens can be used for near-infrared band imaging, and the optical lens comprises a lens barrel, a lens group and a spacer element group located in the lens barrel, The lens group is composed of four lenses, and the lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence along the extension direction of the optical axis; The spacer element group includes at least a first spacer element, the first spacer element is located between the first lens and the second lens and is in contact with a portion of the image side surface of the first lens; The minimum distance EP01 between the object side end surface of the lens barrel and the first spacing element in the extending direction of the optical axis, the maximum thickness CP1 of the first spacing 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; A curvature radius R1 of the object-side surface of the first lens, a refractive index N1 of the first lens, and an inner diameter d1s of the object-side surface of the first spacer element satisfy the following: -4.44≤R1*N1 / d1s≤-1.

71.

2. The optical lens according to claim 1, characterized in that: The curvature radius 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.

3. The optical lens according to claim 1, characterized in that: A curvature radius R3 of the object-side surface of the second lens and an inner diameter d1m of the image-side surface of the first spacer element satisfy the following: -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 surface of the lens barrel and the curvature radius R1 of the object-side surface of the first lens satisfy the following relationship: -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 surface of the lens barrel and the curvature radius R8 of the image side surface of the fourth lens satisfy the following relationship: 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 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 curvature radius 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: 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 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 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 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 curvature radius 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: -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 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 surface of the third lens. The curvature radius 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 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 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 curvature radius 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 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, and 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: 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 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, and 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 space T34 between the third lens and the fourth lens on the optical axis satisfy: 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 refractive 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 a concave surface; The object side surface of the second lens is a concave surface; The image side surface of the third lens is a convex surface; The object side surface of the fourth lens is a convex surface; The image side surface of the fourth lens is a concave surface.

Images