Optical imaging lens

Abstract

The invention provides an optical imaging lens. The optical imaging lens can be used for near-infrared band imaging, the optical imaging lens comprises a lens barrel, a lens group and a spacing element group, and the lens group comprises a first lens, a second lens, a third lens and a fourth lens; the spacing element group comprises a first spacing element and a second spacing element, and the effective focal length f2 of the second lens, the center thickness CT2 of the second lens on the optical axis and the distance EP12 between the image side surface of the first spacing element and the object side surface of the second spacing element in the extension direction of the optical axis meet the condition that f2 / (CT2 + EP12) is greater than or equal to 1.03 and less than or equal to 2.88; the curvature radius R3 of the object side surface of the second lens and the outer diameter D1m of the image side surface of the first spacing element satisfy the following relation:-1.93 < = R3 / D1m < =-0.41. The optical imaging lens solves the problem of serious stray light caused by improvement of assembly stability of an optical imaging lens in the prior art.

Description

Technical Field

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

[0002] With the development of electronic products, imaging systems play an important role in electronic products. Users have more and more demands for the imaging functions of electronic products, especially in electronic products such as AR (Augmented Reality) and VR (Virtual Reality). The requirements for optical imaging lenses are gradually increasing. In VR / AR systems, capturing eye movements through optical imaging lenses and quickly transmitting correct command signals has become an important part of VR / AR systems. Accurate signal transmission and the stray light quality of optical imaging lenses are particularly critical. In optical imaging lenses used in AR and VR products, the relationship between the center thickness and edge thickness of the lens in the middle position is usually controlled to improve the assembly stability of the optical imaging lens, but it is easy to cause serious stray light.

[0003] That is to say, in the prior art, the optical imaging lens has the problem of serious stray light caused by improving the assembly stability. Summary of the invention

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

[0005] To achieve the above-mentioned object, according to one aspect of the present invention, an optical imaging lens is provided, which is used for imaging in the near-infrared band. The optical imaging lens comprises a lens barrel, a lens group and a spacer element group assembled in the lens barrel, wherein the lens group comprises a first lens, a second lens, a third lens and a fourth lens in sequence from the object side to the image side along the optical axis; the spacer element group comprises at least a first spacer element and a second spacer element, the first spacer element is located between the first lens and the second lens and contacts with the image side surface portion of the first lens, and the second spacer element is located between the second lens and the third lens and contacts with the image side surface portion of the second lens; the effective focal length f2 of the second lens, the center thickness CT2 of the second lens on the optical axis, and the distance EP12 between the image side surface of the first spacer element and the object side surface of the second spacer element in the extension direction of the optical axis satisfy the following conditions: 1.03≤f2 / (CT2+EP12)≤2.88; the curvature radius R3 of the object side surface of the second lens and the outer diameter D1m of the image side surface of the first spacer element satisfy the following conditions: -1.93≤R3 / D1m≤-0.41.

[0006] According to another aspect of the present invention, an optical imaging lens is provided, which is used for imaging in a near-infrared band. The optical imaging lens includes a lens barrel, a lens group and a spacer element group assembled in the lens barrel, wherein the lens group includes, from the object side to the image side along the optical axis, a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power and a fourth lens with optical power in sequence; the spacer element group includes at least a first spacer element and a second spacer element, wherein the first spacer element is located between the first lens and the second lens and partially contacts the image side surface of the first lens; a curvature radius R1 of the object side surface of the first lens and an inner diameter d0s of the object side end surface of the lens barrel satisfy the following: -4.37≤R1 / d0s≤-0.66; an air gap T12 between the first lens and the second lens on the optical axis, a center thickness CT1 of the first lens, and a maximum thickness CP1 of the first spacer element satisfy the following: 0.71≤T12 / (CT1+CP1)≤3.13.

[0007] According to another aspect of the present invention, an optical imaging lens is provided, which is used for imaging in the near-infrared band. The optical imaging lens includes a lens barrel, a lens group and a spacer element group assembled in the lens barrel, wherein the lens group includes, from the object side to the image side of the optical axis, a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power and a fourth lens with optical power; the spacer element group includes at least a second spacer element and a third spacer element, wherein the second spacer element is located between the second lens and the third lens and contacts the image side surface of the second lens, and the third spacer element is located between the third lens and the fourth lens and contacts the image side surface of the second lens. It is in partial contact with the image side surface of the third lens; the effective focal length f3 of the third lens, the air gap T34 between the third lens and the fourth lens on the optical axis, and the distance EP23 between the image side surface of the second spacing element and the object side surface of the third spacing element in the extension direction of the optical axis satisfy the following: 1.62≤f3 / (EP23+T34)≤14.81; the curvature radius R6 of the image side surface of the third lens, the curvature radius R7 of the object side surface of the fourth lens, the inner diameter d3s of the object side surface of the third spacing element, and the inner diameter d3m of the image side surface of the third spacing element satisfy the following: -2.74≤R6 / d3s+R7 / d3m≤-1.65.

[0008] Furthermore, a distance EP01 between the object side end surface of the lens barrel and the object side surface of the first spacing element in the extension direction of the optical axis and an effective focal length f1 of the first lens satisfy: -1.73≤f1 / EP01≤-1.34.

[0009] Further, the air interval T12 between the first lens and the second lens on the optical axis, the center thickness CT1 of the first lens, and the maximum thickness CP1 of the first spacing element satisfy: 0.71≤T12 / (CT1+CP1)≤3.13.

[0010] Furthermore, a curvature radius R4 of the image side surface of the second lens, a refractive index N2 of the second lens, and an inner diameter d2s of the object side surface of the second spacer element satisfy: -2.63≤R4*N2 / d2s≤-0.61.

[0011] Furthermore, an outer diameter D2m of the image side surface of the second spacing element, a curvature radius R6 of the image side surface of the third lens, and a refractive index N3 of the third lens satisfy: -2.62≤D2m / (R6*N3)≤-1.28.

[0012] Further, the central thickness CT3 of the third lens, the air interval T23 between the second lens and the third lens on the optical axis, and the maximum thickness CP2 of the second spacing element satisfy: 0.96≤CT3 / (T23+CP2)≤4.33.

[0013] Furthermore, the outer diameter D0s of the object side end surface of the lens barrel, the inner diameter d0s of the object side end surface of the lens barrel, the outer diameter D0m of the image side end surface of the lens barrel, and the inner diameter d0m of the image side end surface of the lens barrel satisfy: 1.41≤(D0m-d0m) / (D0s-d0s)≤3.70.

[0014] Furthermore, the maximum height L of the lens barrel and the sum ΣCT of the center thicknesses of all lenses in the lens group satisfy: 1.64≤L / ΣCT≤2.26.

[0015] Furthermore, a curvature radius R1 of the object side surface of the first lens and an inner diameter d0s of the object side end surface of the lens barrel satisfy: -4.37≤R1 / d0s≤-0.66.

[0016] Furthermore, the spacer element group also includes a third spacer element, which is located between the third lens and the fourth lens and partially contacts the image side surface of the third lens. The effective focal length f3 of the third lens, the air gap T34 between the third lens and the fourth lens on the optical axis, and the distance EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element in the extension direction of the optical axis satisfy: 1.62≤f3 / (EP23+T34)≤14.81.

[0017] Furthermore, the spacer element group also includes a third spacer element, which is located between the third lens and the fourth lens and contacts the image side portion of the third lens, and the inner diameter d3s of the object side of the third spacer element and the curvature radius R7 of the object side of the fourth lens satisfy: -2.05≤R7 / d3s≤-0.62.

[0018] Furthermore, the first lens has negative optical power; the second lens has positive optical power; and the third lens has positive optical power.

[0019] Furthermore, the object side surface of the first lens is concave, and the image side surface of the first lens is concave; the object side surface of the second lens is concave, and the image side surface of the second lens is convex; the object side surface of the third lens is concave, and the image side surface of the third lens is convex; the object side surface of the fourth lens is concave, and the image side surface of the fourth lens is convex.

[0020] According to the technical solution of the present invention, an optical imaging lens is used for imaging in the near-infrared band. The optical imaging lens comprises a lens barrel, a lens group and a spacer element group assembled in the lens barrel, wherein the lens group comprises a first lens, a second lens, a third lens and a fourth lens in sequence from the object side to the image side along the optical axis; the spacer element group comprises at least a first spacer element and a second spacer element, wherein the first spacer element is located between the first lens and the second lens and contacts the image side surface portion of the first lens, and the second spacer element is located between the second lens and the third lens and contacts the image side surface portion of the second lens; the effective focal length f2 of the second lens, the center thickness CT2 of the second lens on the optical axis, and the distance EP12 between the image side surface of the first spacer element and the object side surface of the second spacer element in the extension direction of the optical axis satisfy the following conditions: 1.03≤f2 / (CT2+EP12)≤2.88; the curvature radius R3 of the object side surface of the second lens and the outer diameter D1m of the image side surface of the first spacer element satisfy the following conditions: -1.93≤R3 / D1m≤-0.41.

[0021] The optical imaging lens of the present application is composed of a lens barrel, four lenses and at least two spacer elements. When the effective focal length f2 of the second lens, the center thickness CT2 of the second lens on the optical axis, and the distance EP12 between the image side surface of the first spacer element and the object side surface of the second spacer element in the extension direction of the optical axis satisfy 1.03≤f2 / (CT2+EP12)≤2.88, by optimizing the focal length, center thickness and distance between the first spacer element and the second spacer element, the thickness distribution of the second lens is more uniform, which is conducive to improving the stability of the second lens structure, thereby improving the assembly stability of the optical imaging lens, and at the same time ensuring that the light converges after passing through the second lens, thereby ensuring the imaging quality of the optical imaging lens. However, under this design, when the light passes through the second lens, it is easy to generate a stray light path, resulting in serious stray light. In order to reduce the stray light generated by the optical imaging lens at the second lens, the present application constrains R3 / D1m within a reasonable range to control the curved shape of the object side surface of the second lens, thereby ensuring the transmission path of the light when it enters the second lens. If R3 / D1m is less than -1.93, D1m is small, the curvature radius of the object side of the second lens is small, and the deflection angle of the light is reduced, which easily causes the stray light to be reflected multiple times at the flange position of the first lens. If R3 / D1m is greater than -0.41, R3 is reduced, and D1m is large, and the stray light path is easily reflected directly to the edge of the image plane, which easily leads to high stray light energy. By limiting R3 / D1m to the range of -1.93 to -0.41, the degree of deflection of the light when it enters the second lens is guaranteed, and it is matched with the outer diameter D1m of the image side of the first spacing element, so that the first spacing element absorbs stray light and reduces the reflection of stray light inside the optical imaging lens, thereby achieving the purpose of reducing stray light. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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:

[0023] Figure 1 A dimensioning diagram of an optical imaging lens according to an optional embodiment of the present invention is shown;

[0024] Figure 2 A schematic structural diagram of an optical imaging lens according to Embodiment 1-1 of the present invention is shown;

[0025] Figure 3 A schematic structural diagram of an optical imaging lens according to Embodiment 1-2 of the present invention is shown;

[0026] Figures 4 to 7 The axial chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical imaging lens of the first embodiment of the present invention are respectively shown;

[0027] Figure 8 A schematic structural diagram of an optical imaging lens according to Embodiment 2-1 of the present invention is shown;

[0028] Fig. 9 A schematic structural diagram of an optical imaging lens according to Embodiment 2-2 of the present invention is shown;

[0029] Figures 10 to 13 The axial chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical imaging lens of the second embodiment of the present invention are respectively shown;

[0030] Fig.14 A schematic structural diagram of an optical imaging lens according to Embodiment 3-1 of the present invention is shown;

[0031] Fig.15 A schematic structural diagram of an optical imaging lens according to Embodiment 3-2 of the present invention is shown;

[0032] Figures 16 to 19 The axial chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical imaging lens of the third embodiment of the present invention are respectively shown;

[0033] Fig. 20 A schematic structural diagram of an optical imaging lens according to Embodiment 4-1 of the present invention is shown;

[0034] Fig.21 A schematic structural diagram of an optical imaging lens according to Embodiment 4-2 of the present invention is shown;

[0035] Figure 22 to Figure 25 The axial chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical imaging lens of the fourth embodiment of the present invention are respectively shown;

[0036] Fig.26 A light path diagram of an optical imaging lens according to an optional embodiment of the present invention is shown;

[0037] Fig. 27 Shows Fig.26 The stray light spot diagram of the optical imaging lens shown;

[0038] Fig.28 shows a light path diagram of an optical imaging lens in an example;

[0039] Fig.29 Shows Fig.28 The stray light spot diagram of the optical imaging lens shown;

[0040] Fig.30 shows a light path diagram of an optical imaging lens in another example;

[0041] Fig.31 Shows Fig.30 The stray light spot diagram of the optical imaging lens shown.

[0042] The above drawings include the following reference numerals:

[0043] P0, lens barrel; E1, first lens; P1, first spacing element; E2, second lens; P2, second spacing element; P2b, second auxiliary 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

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] In order to solve the problem of serious stray light caused by improving assembly stability of optical imaging lenses in the prior art, the present invention provides an optical imaging lens.

[0051] like Figures 1 to 25 As shown, the optical imaging lens is used for imaging in the near-infrared band. The optical imaging lens includes a lens barrel, a lens group and a spacer element group assembled in the lens barrel. The lens group includes a first lens, a second lens, a third lens and a fourth lens in sequence from the object side to the image side along the optical axis; the spacer element group includes at least a first spacer element and a second spacer element, the first spacer element is located between the first lens and the second lens and is in contact with the image side portion of the first lens, and the second spacer element is located between the second lens and the third lens and is in contact with the image side portion of the second lens; the effective focal length f2 of the second lens, the center thickness CT2 of the second lens on the optical axis, and the distance EP12 between the image side surface of the first spacer element and the object side surface of the second spacer element in the extension direction of the optical axis satisfy: 1.03≤f2 / (CT2+EP12)≤2.88; the curvature radius R3 of the object side surface of the second lens and the outer diameter D1m of the image side surface of the first spacer element satisfy: -1.93≤R3 / D1m≤-0.41.

[0052] The optical imaging lens of the present application is composed of a lens barrel, four lenses and at least two spacer elements. When the effective focal length f2 of the second lens, the center thickness CT2 of the second lens on the optical axis, and the distance EP12 between the image side surface of the first spacer element and the object side surface of the second spacer element in the extension direction of the optical axis satisfy 1.03≤f2 / (CT2+EP12)≤2.88, by optimizing the focal length, center thickness and distance between the first spacer element and the second spacer element, the thickness distribution of the second lens is more uniform, which is conducive to improving the stability of the second lens structure, thereby improving the assembly stability of the optical imaging lens, and at the same time ensuring that the light converges after passing through the second lens, thereby ensuring the imaging quality of the optical imaging lens. However, under this design, when the light passes through the second lens, it is easy to generate a stray light path, resulting in serious stray light. In order to reduce the stray light generated by the optical imaging lens at the second lens, the present application constrains R3 / D1m within a reasonable range to control the curved shape of the object side surface of the second lens, thereby ensuring the transmission path of the light when it enters the second lens. If R3 / D1m is less than -1.93, D1m is small, the curvature radius of the object side of the second lens is small, and the deflection angle of the light is reduced, which easily causes the stray light to be reflected multiple times at the flange position of the first lens. If R3 / D1m is greater than -0.41, R3 is reduced, and D1m is large, and the stray light path is easily reflected directly to the edge of the image plane, which easily leads to high stray light energy. By limiting R3 / D1m to the range of -1.93 to -0.41, the degree of deflection of the light when it enters the second lens is guaranteed, and it is matched with the outer diameter D1m of the image side of the first spacing element, so that the first spacing element absorbs stray light and reduces the reflection of stray light inside the optical imaging lens, thereby achieving the purpose of reducing stray light.

[0053] In addition, refer to Table 1 and Figure 26 to Figure 31 As shown, Fig.26 The optical path diagram of the optical imaging lens when f2 / (CT2+EP12)=1.88 and R3 / D1m=-0.45 is shown. Fig. 27 for Fig.26 Schematic diagram of stray light in an optical imaging lens.

[0054] Fig.28 The optical path diagram of the optical imaging lens when f2 / (CT2+EP12)=1.88 and R3 / D1m=-2.1 is shown. Fig.29 for Fig.28 Schematic diagram of stray light in an optical imaging lens. Fig.30 The optical path diagram of the optical imaging lens when f2 / (CT2+EP12)=1.88 and R3 / D1m=-0.3 is shown. Fig.31 for Fig.30 Schematic diagram of stray light in an optical imaging lens.

[0055] Depend on Figure 26 to Figure 31 It can be seen that when R3 / D1m=-0.45, the stray light energy is weakened, the stray light is improved, and the performance is better. When R3 / D1m=-2.1 is satisfied, stray light is easily generated at the position of the first spacing element, the stray light energy is relatively strong, the stray light has a greater impact on the imaging quality, and the performance is poor. When R3 / D1m=-0.3 is satisfied, stray light is easily generated between the second lens and the first lens, the stray light energy is relatively 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-d1s) is in the range of -4.13 to 0.89, the stray light improvement effect of the optical imaging lens is best. Therefore, the present application reasonably constrains the relationship between the radius of curvature of the object side of the second lens and the inner diameter of the first spacing element by constraining -1.93≤R3 / D1m≤-0.41, which is beneficial to reducing the stray light generated at the second lens and the first spacing element, thereby weakening the influence of stray light on imaging quality and ensuring the imaging quality of the optical imaging lens.

[0056]

[0057] Table 1

[0058] It should be noted that the present application limits R3 / D1m within a reasonable range to control the degree of deflection of light on the object side of the second lens and the size of the first spacing element, improve the smoothness of the light path, and solve the stray light problem caused by f2 / (CT2+EP12) in the range of 1.03 to 2.88. When R3 / D1m meets the above range, the purpose of reducing 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 imaging 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 also be convex or concave according to the design requirements of the optical system. The optical system meets the following requirements: 1.03≤f2 / (CT2+EP12)≤2.88, -1.93≤R3 / D1m≤-0.41, and the purpose of reducing stray light can be achieved.

[0059] For example, the first lens has negative optical power, the second lens has positive optical power, and the third lens has positive optical power. For another example, the object side surface of the first lens is concave, and the image side surface of the first lens is concave; the object side surface of the second lens is concave, and the image side surface of the second lens is convex; the object side surface of the third lens is concave, and the image side surface of the third lens is convex; the object side surface of the fourth lens is concave, and the image side surface of the fourth lens is convex. The optical imaging lens can be simulated by software and / or tools such as ZEMAX and CODEV. In the process of simulation using the above-mentioned software and / or tools, 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 optical imaging lens is used to image light with a wavelength greater than or equal to 780 nm and less than or equal to 2526 nm. The optical imaging lens can image light in the near-infrared band, effectively expanding the application environment of the optical imaging lens.

[0061] In some optional embodiments, the distance EP01 between the object side end face of the lens barrel and the object side face of the first spacing element in the extension direction of the optical axis and the effective focal length f1 of the first lens satisfy: -1.73≤f1 / EP01≤-1.34. By limiting f1 / EP01 to a reasonable range, the edge thickness of the first lens and the glue dispensing space reserved in front of the first lens can be guaranteed while controlling the degree of deflection of the light in the first lens, which is conducive to matching with the second lens with positive optical power at the rear to ensure a smooth transition of light between the first lens and the second lens and to ensure imaging quality. Reserving sufficient glue dispensing space in front of the first lens can prevent the lens from having appearance problems such as glue overflow, while ensuring the edge thickness of the first lens can ensure the molding quality of the first lens and reduce the appearance problems of the first lens molding.

[0062] In some optional embodiments, the air gap T12 between the first lens and the second lens on the optical axis, the center thickness CT1 of the first lens, and the maximum thickness CP1 of the first spacing element satisfy: 0.71≤T12 / (CT1+CP1)≤3.13. By limiting T12 / (CT1+CP1) within a reasonable range, a larger spacing between the first lens and the second lens is ensured, which is beneficial to preventing the first lens from floating after baking the optical imaging lens and other adverse effects on the assembly stability of the optical imaging lens. At the same time, limiting the center thickness of the first lens and the maximum thickness of the first spacing element is beneficial to reducing the impact of the center thickness tolerance of the first lens and the image side sagittal height tolerance on the production yield of the optical imaging lens.

[0063] In some optional embodiments, 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 spacer element satisfy: -2.63≤R4*N2 / d2s≤-0.61. By limiting R4*N2 / d2s to a reasonable range, the degree of deflection of light passing through the image side surface of the second lens can be guaranteed, so that the imaging light can pass through the second spacer element smoothly while the second spacer element can effectively intercept the stray light generated at the flange surface of the second lens, thereby improving the improvement effect of the optical imaging lens on stray light. In addition, the image side surface of the second lens is set as a convex surface, so that the light passing through the image side surface of the second lens has a convergence effect, which is conducive to the convergence of light at the aperture.

[0064] In some optional embodiments, the outer diameter D2m of the image side surface of the second spacer element, the curvature radius R6 of the image side surface of the third lens and the refractive index N3 of the third lens satisfy: -2.62≤D2m / (R6*N3)≤-1.28. By limiting D2m / (R6*N3) within a reasonable range, the reflected light from the flange surface of the second lens entering the third lens can be reduced, and the degree of light deflection in the third lens can be controlled, so that the ghost image spot generated by the third lens can be reduced to a minimum level, thereby ensuring the imaging quality of the optical imaging lens.

[0065] In some optional embodiments, the central thickness CT3 of the third lens, the air interval T23 between the second lens and the third lens on the optical axis, and the maximum thickness CP2 of the second spacing element satisfy: 0.96≤CT3 / (T23+CP2)≤4.33. Since the air interval between the second lens and the third lens is sensitive to the optical performance, which is mainly manifested in the influence on the external field curvature, by limiting the relationship between the central thickness of the third lens, the air interval between the second lens and the third lens on the optical axis, and the maximum thickness of the second spacing element, the sensitivity of the thickness of the third lens and the air interval between the second lens and the third lens to the optical performance can be reduced.

[0066] In some optional embodiments, the outer diameter D0s of the object side end surface of the lens barrel, the inner diameter d0s of the object side end surface of the lens barrel, the outer diameter D0m of the image side end surface of the lens barrel, and the inner diameter d0m of the image side end surface of the lens barrel satisfy: 1.41≤(D0m-d0m) / (D0s-d0s)≤3.70. By constraining (D0m-d0m) / (D0s-d0s) within a reasonable range, the external shape of the optical imaging lens can be guaranteed. On the one hand, the characteristics of the small head can be realized, so that the optical imaging lens can be applied to more application scenarios. On the other hand, the outer diameter of the small head end lens barrel can be increased, and the assembly stability of the optical imaging lens can be improved.

[0067] In some optional embodiments, the maximum height L of the lens barrel and the sum of the center thicknesses ∑CT of all lenses in the lens group satisfy: 1.64≤L / ∑CT≤2.26. By limiting L / ∑CT within a reasonable range, the ratio of the sum of the center thicknesses of the lenses in the lens group to the maximum height of the lens barrel can be ensured, and the reasonable distribution of the air space in the lens group and the center thickness of the lenses can be ensured, thereby improving the stability of the air space before and after the optical imaging lens is baked, and ensuring the optical performance of the optical imaging lens.

[0068] In some optional embodiments, the radius of curvature R1 of the object side surface of the first lens and the inner diameter d0s of the object side end surface of the lens barrel satisfy: -4.37≤R1 / d0s≤-0.66. By limiting R1 / d0s within a reasonable range, the curvature of the object side surface of the first lens can be guaranteed, the field of view of the optical imaging lens can be guaranteed, and the inner diameter of the object side end surface of the lens barrel can be limited to avoid the lens barrel intercepting light and affecting the imaging brightness, thereby ensuring the luminous flux of the optical imaging lens.

[0069] 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 partially contacts the image side surface of the third lens, and the effective focal length f3 of the third lens, the air gap T34 between the third lens and the fourth lens on the optical axis, and the distance EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element in the extension direction of the optical axis satisfy: 1.62≤f3 / (EP23+T34)≤14.81. By limiting f3 / (EP23+T34) within a reasonable range, the degree of light deflection in the third lens is controlled, and the air gap between the third lens and the fourth lens on the optical axis is matched to provide space for improving the stray light emitted by the third lens, thereby ensuring the effect of improving the stray light of the optical imaging lens, and at the same time ensuring the molding of the third lens and the yield of the third lens.

[0070] 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 partially contacts the image side surface of the third lens, and the inner diameter d3s of the object side surface of the third spacer element and the curvature radius R7 of the object side surface of the fourth lens satisfy: -2.05≤R7 / d3s≤-0.62. By limiting R7 / d3s within a reasonable range, the degree of deflection of light on the object side surface of the fourth lens is controlled, ensuring that the stray light path emitted by the third lens is intercepted by the third spacer element, so as to reduce the stray light reaching the imaging surface and ensure the imaging quality of the optical imaging lens.

[0071] In addition, in another optional embodiment of the present application, an optical imaging lens is also provided, which is used for imaging in the near-infrared band. The optical imaging lens includes a lens barrel and a lens group and a spacer element group assembled in the lens barrel. The lens group includes a first lens with negative optical focal length, a second lens with positive optical focal length, a third lens with positive optical focal length and a fourth lens with optical focal length in sequence from the object side to the image side along 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 is in contact with the image side portion of the first lens; the curvature radius R1 of the object side surface of the first lens and the inner diameter d0s of the object side end surface of the lens barrel satisfy: -4.37≤R1 / d0s≤-0.66; the air gap T12 between the first lens and the second lens on the optical axis, the center thickness CT1 of the first lens, and the maximum thickness CP1 of the first spacer element satisfy: 0.71≤T12 / (CT1+CP1)≤3.13.

[0072] The optical imaging lens of the present application is composed of a lens barrel, four lenses and at least one spacer element. When the radius of curvature R1 of the object side surface of the first lens and the inner diameter d0s of the object side end surface of the lens barrel satisfy -4.37≤R1 / d0s≤-0.66, by optimizing the curvature of the object side surface of the first lens and the inner diameter of the object side end surface of the lens barrel, the object side surface of the first lens can receive more light, which is conducive to large-angle light incident on the interior of the optical lens, and is conducive to improving the imaging brightness and the field of view of the optical lens. However, due to the large inner diameter d0s of the object side end surface of the lens barrel, it is easy to cause the first lens to tilt and misalign during installation, which affects the assembly stability of the optical imaging lens. The present application constrains T12 / (CT1+CP1) within a reasonable range to ensure a large spacing between the first lens and the second lens, which is beneficial to preventing the first lens from floating after the optical imaging lens is baked, and other adverse effects on the assembly stability of the optical imaging lens. At the same time, the center thickness of the first lens and the thickness of the first spacing element are limited to ensure the support strength of the first lens and the structural strength of the first lens, which is beneficial to improving the stability of the first lens 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] In addition, in another optional embodiment of the present application, an optical imaging lens is further provided. The optical imaging lens is used for imaging in the near-infrared band. The optical imaging lens includes a lens barrel and a lens group and a spacer element group assembled in the lens barrel. The lens group includes, from the object side to the image side of the optical axis, a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, and a fourth lens with optical power; the spacer element group includes at least a second spacer element and a third spacer element, the second spacer element is located between the second lens and the third lens and is in contact with the image side portion of the second lens, and the third spacer element is located between the third lens and the fourth lens. The second spacing element is between the two lenses and is in contact with the image side surface of the third lens; the effective focal length f3 of the third lens, the air gap T34 between the third lens and the fourth lens on the optical axis, and the distance EP23 between the image side surface of the second spacing element and the object side surface of the third spacing element in the extension direction of the optical axis satisfy the following: 1.62≤f3 / (EP23+T34)≤14.81; the curvature radius R6 of the image side surface of the third lens, the curvature radius R7 of the object side surface of the fourth lens, the inner diameter d3s of the object side surface of the third spacing element, and the inner diameter d3m of the image side surface of the third spacing element satisfy the following: -2.74≤R6 / d3s+R7 / d3m≤-1.65.

[0075] The optical imaging lens of the present application is composed of a lens barrel, four lenses and at least two spacer elements. When the effective focal length f3 of the third lens, the air gap T34 between the third lens and the fourth lens on the optical axis, and the distance EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element in the extension direction of the optical axis satisfy the following conditions: 1.62≤f3 / (EP23+T34)≤14.81, by optimizing the focal length of the third lens, the air gap between the third lens and the fourth lens, and the distance between the second spacer element and the third spacer element, it is beneficial to control the degree of deflection of light when entering and exiting the third lens, and at the same time, limiting the relationship between f3, EP23, and T34, so as to ensure the molding of the third lens, ensure the yield of the third lens, and provide space for improving the stray light emitted by the third lens. However, by constraining f3 / (EP23+T34) within the above range, the improvement effect on the stray light is poor. The present application simultaneously constrains the relationship between the curvature radius of the image-side surface of the third lens, the curvature radius of the object-side surface of the fourth lens, and the inner diameter of the third spacing element, which can optimize the exit angle and exit direction of the light from the third lens, as well as the incident angle and incident direction of the light entering the fourth lens, and optimizes the transmission path, angle, and maximum light range of the light between the third lens and the fourth lens. At the same time, the constraint of f3 / (EP23+T34) on the space between the third lens and the fourth lens further reduces stray light and improves the imaging quality of the optical imaging 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 imaging lens may further include a protective glass for protecting a photosensitive element located on the imaging surface.

[0080] The optical imaging 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.

[0081] 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 imaging 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 imaging lens is not limited to including four lenses. If necessary, the optical imaging lens may also include other numbers of lenses.

[0082] Figure 1 A schematic diagram of the dimensions of an optical imaging lens of the present application is shown. Figure 1 Parameters such as D1m, d2s, D2m, d3s, d0s, d0m, D0s, D0m, CP1, CP2, EP01, EP12, EP23, and L are indicated in the figure to clearly and intuitively understand the meaning of the parameters. In order to facilitate the description of the optical imaging 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.

[0083] The following further describes examples of specific surface shapes and parameters of the optical imaging lens applicable to the above-mentioned embodiments with reference to the accompanying drawings.

[0084] It should be noted that in the following embodiment 1, there are two examples, namely, embodiment 1-1 and embodiment 1-2; in embodiment 2, there are two examples, namely, embodiment 2-1 and embodiment 2-2; in embodiment 3, there are two examples, namely, embodiment 3-1 and embodiment 3-2; and in embodiment 4, there are two examples, namely, embodiment 4-1 and embodiment 4-2. In the two examples of the same embodiment, the parameters such as the radius of curvature, center thickness, and spacing distance between lenses of the optical imaging lens are the same, but the parameters such as the thickness, inner diameter, and 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.

[0085] It should be noted that any one of the following embodiments 1 to 3 is applicable to the present application.

[0086] Embodiment 1

[0087] like Figures 2 to 7 As shown, the optical imaging lens of the first embodiment is described. Figure 2 FIG. 1 is a schematic diagram showing the structure of the optical imaging lens of Example 1-1. Figure 3 A schematic structural diagram of the optical imaging lens of Embodiment 1-2 is shown.

[0088] like Figure 2 and Figure 3 As shown, the optical imaging lens includes a lens barrel P0, four lenses and multiple spacer elements. The lens barrel P0 includes a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, a third lens E3, a third spacer element P3 and a fourth lens E4 arranged in sequence from the object side to the image side.

[0089] like Figure 2As shown, it is a structural schematic diagram of the optical imaging lens of Example 1-1. In Example 1-1, the spacer element group also includes a second auxiliary spacer element P2b, and the second auxiliary spacer element P2b is located between the second spacer element P2 and the third lens E3. The object side surface S1 of the first lens is spaced from the lens barrel P0, and the outer annular surface of the first lens E1 partially abuts against the inner wall surface of the lens barrel P0. The object side surface and the image side surface of the first spacer element P1 are respectively abutted against the image side surface S2 of the first lens and the object side surface S3 of the second lens. The object side surface and the image side surface of the second spacer element P2 are respectively abutted against the image side surface S4 of the second lens and the object side surface of the second auxiliary spacer element P2b, the image side surface of the second auxiliary spacer element P2b is partially abutted against the object side surface S5 of the third lens, the object side surface and the image side surface of the third spacer element P3 are respectively abutted against the image side surface S6 of the third lens and the object side surface S7 of the fourth lens, and the image side surface S8 of the fourth lens is partially abutted against the lens barrel P0.

[0090] like Figure 3 As shown, it is a schematic diagram of the structure of the optical imaging lens of Example 1-2. In Example 1-2, the spacer element group does not have a second auxiliary spacer element P2b, but the spacer element group also includes a third auxiliary spacer element P3b, and the third auxiliary spacer element P3b is located between the third spacer element P3 and the fourth lens E4. In Example 1-2, the image side surface of the second spacer element P2 is partially abutted against the object side surface S5 of the third lens. The object side surface and image side surface of the third auxiliary spacer element P3b are respectively abutted against the image side surface of the third spacer element and the object side surface S7 of the fourth lens. The supporting and abutting methods of other spacer elements are similar to those in Example 1-1, and the relevant description in Example 1-1 may be referred to, and no further description is given here.

[0091] In the first embodiment, the first lens has negative power, the object side surface S1 of the first lens is concave, and the image side surface S2 of the first lens is concave. The second lens has positive power, the object side surface S3 of the second lens is concave, and the image side surface S4 of the second lens is convex. The third lens has positive power, the object side surface S5 of the third lens is concave, and the image side surface S6 of the third lens is convex; the fourth lens has positive power, the object side surface S7 of the fourth lens is concave, and the image side surface S8 of the fourth lens is convex.

[0092] Table 2 shows the basic structural parameters of the optical imaging lens of Example 1, wherein the units of the radius of curvature and thickness / distance are all millimeters.

[0093]

[0094]

[0095] Table 2

[0096] 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:

[0097]

[0098] 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.

[0099] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 A22 A24 A26 A28 S1 3.13E-01 -5.79E-02 1.10E-02 -4.10E-03 1.36E-03 -5.26E-04 1.69E-04 -8.79E-05 2.45E-05 -1.90E-06 5.24E-06 0.00E+00 0.00E+00 S2 1.44E-01 -2.32E-02 -7.42E-03 -4.32E-03 -1.13E-03 -2.66E-04 -3.55E-05 -5.67E-07 -1.86E-05 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S3 -2.76E-02 1.02E-03 1.97E-04 4.67E-05 2.39E-05 9.54E-06 7.27E-06 -1.18E-06 1.52E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S4 -3.13E-02 -4.56E-04 3.03E-04 -2.08E-04 8.25E-05 -2.82E-05 1.03E-05 -4.21E-06 1.84E-06 -9.17E-07 1.34E-07 0.00E+00 0.00E+00 S5 2.63E-02 -4.83E-03 6.21E-04 -1.98E-04 3.68E-05 -1.09E-05 1.93E-06 -6.11E-07 -7.12E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 -1.31E-02 -1.18E-03 -3.14E-05 -4.86E-05 4.97E-06 -3.08E-06 -5.97E-07 2.57E-07 -1.98E-07 -4.99E-07 2.63E-07 0.00E+00 0.00E+00 S7 1.40E-02 2.61E-03 2.19E-04 8.15E-05 4.02E-05 8.98E-06 -3.19E-06 -3.11E-06 -1.29E-08 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S8 6.89E-02 8.39E-03 1.16E-03 3.67E-04 1.76E-04 5.32E-05 1.53E-05 1.35E-06 4.83E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0100] Table 3

[0101] Figure 4 The axial chromatic aberration curve of the optical imaging lens of the first embodiment is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the optical imaging lens. Figure 5 The astigmatism curve of the optical imaging lens of the first embodiment is shown, which represents the meridional image curvature and the sagittal image curvature. Figure 6 The distortion curve of the optical imaging lens of the first embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. Figure 7 The magnification chromatic aberration curve of the optical imaging lens of the first embodiment is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the lens.

[0102] according to Figures 4 to 7 It can be seen that the optical imaging lens provided in the first embodiment can achieve good imaging quality.

[0103] Embodiment 2

[0104] like Figures 8 to 13 As shown, the optical imaging lens of the second embodiment is described. Figure 8 FIG. 2 shows a schematic structural diagram of an optical imaging lens of Example 2-1. Fig. 9 A schematic structural diagram of the optical imaging lens of Example 2-2 is shown.

[0105] like Figure 8 and Fig. 9As shown, the optical imaging lens includes a lens barrel P0, four lenses and multiple spacer elements. The lens barrel P0 includes a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, a third lens E3, a third spacer element P3 and a fourth lens E4 arranged in sequence from the object side to the image side.

[0106] like Figure 8 , which is a schematic diagram of the structure of the optical imaging lens of Example 2-1. The object side surface S1 of the first lens is spaced apart from the lens barrel P0, and the outer annular surface of the first lens E1 partially abuts against the inner wall surface of the lens barrel P0. The object side surface and the image side surface of the first spacing element P1 partially abut against the image side surface S2 of the first lens and the object side surface S3 of the second lens, respectively. The object side surface and the image side surface of the second spacing element P2 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 the image side surface of the third spacing element P3 partially abut against the image side surface S6 of the third lens and the object side surface S7 of the fourth lens, and the image side surface S8 of the fourth lens partially abuts against the lens barrel P0.

[0107] like Fig. 9 FIG. 2 is a schematic diagram of the structure of the optical imaging lens of Example 2-2. In Example 2-2, the abutting manner of each spacing element is similar to that of Example 2-1, and the relevant description in Example 2-1 may be referred to, and will not be repeated here.

[0108] In the second embodiment, the first lens has negative power, the object side surface S1 of the first lens is concave, and the image side surface S2 of the first lens is concave. The second lens has positive power, the object side surface S3 of the second lens is concave, and the image side surface S4 of the second lens is convex. The third lens has positive power, the object side surface S5 of the third lens is concave, and the image side surface S6 of the third lens is convex; the fourth lens has negative power, the object side surface S7 of the fourth lens is concave, and the image side surface S8 of the fourth lens is convex.

[0109] Table 4 shows a basic structural parameter table of the optical imaging lens of Example 2, wherein the units of the radius of curvature and thickness / distance are all millimeters.

[0110] Table 4

[0111] Table 5 shows the high-order coefficients of each aspherical mirror surface that can be used in Example 2, wherein each aspherical surface shape can be defined by formula (1) given in Example 1. In this embodiment, the object side surface and image side surface of the first to fourth lenses are all aspherical surfaces.

[0112] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 A22 A24 A26 A28 S1 3.29E-01 -5.98E-02 1.34E-02 -4.66E-03 1.83E-03 -5.91E-04 2.46E-04 -7.13E-05 6.07E-05 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S2 1.64E-01 -1.70E-02 -8.18E-03 -3.75E-03 -1.12E-04 5.67E-04 2.78E-04 5.59E-05 -2.26E-05 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S3 -2.17E-02 7.11E-04 7.96E-05 7.24E-05 -6.29E-06 -1.69E-07 3.02E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S4 4.99E-02 -2.44E-03 1.08E-03 -1.10E-04 4.67E-05 -7.74E-06 3.69E-07 -2.99E-06 -4.44E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S5 4.74E-02 -6.83E-03 9.27E-04 -2.95E-04 4.98E-05 -1.90E-05 2.78E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 6.52E-04 -8.88E-04 1.02E-04 -7.48E-05 1.30E-05 -5.66E-06 7.38E-07 2.61E-08 9.74E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S7 1.71E-02 -8.47E-04 -2.33E-05 -3.20E-05 2.89E-05 6.01E-06 -1.81E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S8 5.07E-02 4.43E-05 -2.84E-04 -2.27E-05 3.57E-05 3.59E-06 -9.82E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0113] Table 5

[0114] Fig.10 The axial chromatic aberration curve of the optical imaging lens of the second embodiment is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the optical imaging lens. Fig.11 The astigmatism curve of the optical imaging lens of the second embodiment is shown, which represents the meridional image curvature and the sagittal image curvature. Fig.12 The distortion curve of the optical imaging lens of the second embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. Fig.13 The chromatic aberration curve of the optical imaging lens of the second embodiment is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the lens.

[0115] according to Figures 10 to 13 It can be seen that the optical imaging lens provided in the second embodiment can achieve good imaging quality.

[0116] Embodiment 3

[0117] like Figures 14 to 19 As shown, the optical imaging lens of embodiment 3 is described. Fig.14 FIG. 3 is a schematic diagram showing the structure of the optical imaging lens of Example 3-1. Fig.15 A schematic structural diagram of the optical imaging lens of Example 3-2 is shown.

[0118] like Fig.14 and Fig.15 As shown, the optical imaging lens includes a lens barrel P0, four lenses and multiple spacer elements. The lens barrel P0 includes a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, a third lens E3, a third spacer element P3 and a fourth lens E4 arranged in sequence from the object side to the image side.

[0119] like Fig.14 , which is a schematic diagram of the structure of the optical imaging lens of Example 3-1. The object side surface S1 of the first lens is spaced apart from the lens barrel P0, and the outer annular surface of the first lens E1 partially abuts against the inner wall surface of the lens barrel P0. The object side surface and the image side surface of the first spacing element P1 partially abut against the image side surface S2 of the first lens and the object side surface S3 of the second lens, respectively. The object side surface and the image side surface of the second spacing element P2 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 the image side surface of the third spacing element P3 partially abut against the image side surface S6 of the third lens and the object side surface S7 of the fourth lens, and the image side surface S8 of the fourth lens partially abuts against the lens barrel P0.

[0120] like Fig.15As shown, it is a schematic diagram of the structure of the optical imaging lens of Example 3-2. In Example 3-2, the spacer element group also includes a third auxiliary spacer element P3b, and the third auxiliary spacer element P3b is located between the third spacer element P3 and the fourth lens E4. In Example 3-2, the image side surface of the second spacer element P2 is partially abutted against the object side surface S5 of the third lens. The object side surface and image side surface of the third auxiliary spacer element P3b are respectively abutted against the image side surface of the third spacer element and the object side surface S7 of the fourth lens. The supporting and abutting methods of other spacer elements are similar to those in Example 3-1, and the relevant description in Example 3-1 may be referred to, which will not be repeated here.

[0121] In the third embodiment, the first lens has negative power, the object side surface S1 of the first lens is concave, and the image side surface S2 of the first lens is concave. The second lens has positive power, the object side surface S3 of the second lens is concave, and the image side surface S4 of the second lens is convex. The third lens has positive power, the object side surface S5 of the third lens is concave, and the image side surface S6 of the third lens is convex; the fourth lens has positive power, the object side surface S7 of the fourth lens is concave, and the image side surface S8 of the fourth lens is convex.

[0122] Table 6 shows a basic structural parameter table of the optical imaging lens of Example 3, wherein the units of the radius of curvature and thickness / distance are all millimeters.

[0123]

[0124] Table 6

[0125] Table 7 shows the coefficients of the higher order terms of each aspheric mirror surface that can be used in Example 3, wherein the surface type of each aspheric surface can be defined by the formula (1) given in the above Example 1. In this embodiment, the object side surface and the image side surface of the first lens to the fourth lens are all aspheric surfaces.

[0126] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 A22 A24 A26 A28 S1 3.15E-01 -3.38E-02 7.99E-03 -2.16E-03 8.48E-04 -1.51E-04 8.62E-05 -3.29E-05 1.01E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S2 1.52E-01 -8.22E-03 6.71E-04 -2.42E-03 -2.57E-05 -1.23E-04 1.08E-04 -1.91E-05 1.03E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S3 -1.17E-03 1.84E-03 -1.92E-04 8.52E-06 -1.89E-07 2.05E-09 -8.59E-12 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S4 4.15E-02 -3.76E-04 9.52E-04 4.16E-05 6.97E-05 1.29E-05 7.39E-06 -2.51E-07 -1.36E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S5 2.52E-02 -3.72E-03 4.29E-04 -1.25E-04 1.41E-05 -9.63E-08 -3.34E-08 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 -1.84E-03 5.03E-04 7.47E-06 -4.19E-05 1.08E-05 -9.32E-07 -3.61E-09 5.16E-09 -2.22E-10 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S7 1.13E-02 4.09E-04 -6.51E-04 1.67E-05 5.24E-05 1.20E-05 -5.14E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S8 5.36E-02 -5.27E-04 -1.34E-03 7.18E-05 9.10E-05 -2.84E-06 -1.28E-05 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0127] Table 7

[0128] Fig.16 The axial chromatic aberration curve of the optical imaging lens of the third embodiment is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the optical imaging lens. Fig.17 The astigmatism curve of the optical imaging lens of the third embodiment is shown, which represents the meridional image curvature and the sagittal image curvature. Fig.18 The distortion curve of the optical imaging lens of the third embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. Fig.19 The magnification chromatic aberration curve of the optical imaging 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.

[0129] according to Figures 16 to 19 It can be seen that the optical imaging lens provided in the third embodiment can achieve good imaging quality.

[0130] Embodiment 4

[0131] like Figure 20 to Figure 25 As shown, the optical imaging lens of Example 4 is described. Fig. 20 FIG. 4 is a schematic diagram showing the structure of the optical imaging lens of Example 4-1. Fig.21 A schematic structural diagram of the optical imaging lens of Example 4-2 is shown.

[0132] like Fig. 20 and Fig.21 As shown, the optical imaging lens includes a lens barrel P0, four lenses and multiple spacer elements. The lens barrel P0 includes a first lens E1, a first spacer element P1, 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.

[0133] like Fig. 20 As shown, it is a schematic diagram of the structure of the optical imaging lens of Example 4-1. The object side surface S1 of the first lens is spaced apart from the lens barrel P0, and the outer annular surface of the first lens E1 partially abuts against the inner wall surface of the lens barrel P0. The object side surface and the image side surface of the first spacing element P1 partially abut against the image side surface S2 of the first lens and the object side surface S3 of the second lens, respectively. The object side surface and the image side surface of the second spacing element P2 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 of the third spacing element P3 partially abuts against the image side surface S6 of the third lens, the object side surface and the image side surface of the third auxiliary spacing element P3b partially abut against the image side surface S7 of the third spacing element P3 and the object side surface S7 of the fourth lens, and the image side surface S8 of the fourth lens partially abuts against the lens barrel P0.

[0134] like Fig.21 FIG. 4 is a schematic diagram of the structure of the optical imaging lens of Example 4-2. In Example 4-2, the abutting manner of each spacing element is similar to that of Example 4-1, and the relevant description in Example 4-1 may be referred to, and will not be repeated here.

[0135] In the fourth embodiment, the first lens has negative power, the object side surface S1 of the first lens is concave, and the image side surface S2 of the first lens is concave. The second lens has positive power, the object side surface S3 of the second lens is concave, and the image side surface S4 of the second lens is convex. The third lens has positive power, the object side surface S5 of the third lens is concave, and the image side surface S6 of the third lens is convex; the fourth lens has positive power, the object side surface S7 of the fourth lens is concave, and the image side surface S8 of the fourth lens is convex.

[0136] Table 8 shows a basic structural parameter table of the optical imaging lens of Example 4, wherein the units of the radius of curvature and thickness / distance are all millimeters.

[0137]

[0138]

[0139] Table 8

[0140] Table 9 shows the coefficients of the higher order terms that can be used for each aspherical mirror surface in Example 4, wherein each aspherical surface type can be defined by the formula (1) given in the above Example 1. In this embodiment, the object side surface and the image side surface of the first lens to the fourth lens are all aspherical surfaces.

[0141] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 A22 A24 A26 A28 S1 1.37E-01 -2.46E-02 5.51E-03 -1.41E-03 3.94E-04 -1.68E-04 4.78E-05 -1.36E-05 -4.56E-06 -5.05E-06 -4.00E-06 0.00E+00 0.00E+00 S2 1.11E-01 -1.75E-03 -4.12E-04 -5.80E-04 -4.44E-04 -2.03E-04 -1.57E-04 -2.77E-05 -3.20E-05 -1.70E-06 -1.17E-05 0.00E+00 0.00E+00 S3 5.12E-04 -1.92E-03 -5.78E-04 -1.92E-04 -1.05E-04 -3.30E-05 -2.13E-05 -6.93E-06 -5.44E-06 -1.56E-06 -2.86E-06 0.00E+00 0.00E+00 S4 2.57E-02 -6.56E-04 3.89E-04 1.40E-05 1.39E-05 5.70E-07 1.23E-06 3.01E-07 8.72E-07 -4.10E-07 2.11E-07 0.00E+00 0.00E+00 S5 1.79E-02 -2.56E-03 3.73E-04 -2.87E-05 7.67E-06 3.71E-06 -1.59E-06 1.50E-06 -1.23E-06 6.64E-07 -5.01E-07 0.00E+00 0.00E+00 S6 -1.35E-02 -1.51E-03 -1.43E-05 -1.02E-05 2.27E-05 1.47E-06 4.88E-06 -1.33E-06 6.56E-07 -8.76E-07 2.36E-07 0.00E+00 0.00E+00 S7 3.47E-02 -3.21E-03 -6.86E-04 2.32E-04 -2.65E-05 1.65E-05 -7.04E-06 -1.81E-06 -3.92E-06 5.14E-07 -1.84E-06 0.00E+00 0.00E+00 S8 5.48E-02 3.74E-04 -1.47E-03 3.42E-04 -4.27E-05 2.79E-05 -1.34E-05 -1.36E-05 -4.56E-06 -5.05E-06 -4.00E-06 0.00E+00 0.00E+00

[0142] Table 9

[0143] Fig. 22 The axial chromatic aberration curve of the optical imaging lens of the fourth embodiment is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the optical imaging lens. Fig.23 The astigmatism curve of the optical imaging lens of Example 4 is shown, which represents the meridional image curvature and the sagittal image curvature. Fig.24 The distortion curve of the optical imaging lens of the fourth embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. Fig.25 The magnification chromatic aberration curve of the optical imaging lens of Example 4 is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the lens.

[0144] according to Figure 22 to Figure 25 It can be seen that the optical imaging lens provided in the fourth embodiment can achieve good imaging quality.

[0145] In summary, the optical imaging lenses of Embodiments 1 to 4 respectively satisfy the relationships shown in Table 10.

[0146]

[0147]

[0148] Table 10

[0149] Table 11 shows the parameters of each lens of the optical imaging lens of Examples 1 to 4 (unit: mm).

[0150] Parameters / Examples 1-1 1-2 2-1 2-2 3-1 3-2 4-2 4-3 D1m 1.727 1.895 2.069 1.853 2.092 1.919 1.546 1.991 d2s 0.881 0.477 0.477 0.480 0.483 0.450 0.498 0.510 D2m 1.474 1.795 1.969 1.753 1.493 1.430 1.446 1.594 d3s 0.553 0.807 0.512 0.515 0.561 0.659 0.653 0.610 d0s 1.957 2.076 2.368 2.057 2.349 2.111 1.717 2.137 d0m 0.972 0.934 0.969 0.918 0.925 1.019 0.895 0.989 D0s 2.511 2.610 2.808 2.693 2.583 2.654 2.170 2.433 D0m 1.907 2.081 1.713 2.277 1.789 1.837 1.535 1.753 CP1 0.022 0.022 0.022 0.022 0.022 0.022 0.022 0.022 CP2 0.199 0.022 0.022 0.022 0.022 0.022 0.022 0.022 EP01 0.571 0.588 0.569 0.547 0.483 0.619 0.388 0.424 EP12 0.222 0.376 0.307 0.302 0.250 0.250 0.314 0.313 EP23 0.218 0.128 0.193 0.202 0.222 0.124 0.169 0.121 L 1.714 1.704 1.600 1.581 1.469 1.601 1.570 1.641 f1 -0.99 -0.99 -0.94 -0.94 -0.83 -0.83 -0.60 -0.60 f2 0.65 0.65 0.70 0.70 0.81 0.81 1.65 1.65 f3 4.50 4.50 1.96 1.96 1.27 1.27 0.78 0.78 f4 6.27 6.27 -30.54 -30.54 13.76 13.76 18.00 18.00

[0151] Table 11

[0152] The present application also provides an imaging device, whose electronic photosensitive element can be a photosensitive coupled device (CCD) or a complementary metal oxide semiconductor element (CMOS). The imaging device can be an independent imaging device such as a digital camera, or an imaging module integrated in a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical imaging lens described above.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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 imaging lens, characterized in that: The optical imaging lens can be used for near-infrared band imaging, and the optical imaging lens comprises a lens barrel, and a lens group and a spacer element group assembled 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 in sequence from the object side to the image side along the optical axis; The spacer element group includes at least a first spacer element and a second spacer element, the first spacer element is located between the first lens and the second lens and contacts the image side surface of the first lens, and 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 effective focal length f2 of the second lens, the center thickness CT2 of the second lens on the optical axis, and the distance EP12 between the image side surface of the first spacing element and the object side surface of the second spacing element in the extending direction of the optical axis satisfy the following: 1.03≤f2 / (CT2+EP12)≤2.88; A curvature radius R3 of the object side surface of the second lens and an outer diameter D1m of the image side surface of the first spacer element satisfy the following: -1.93≤R3 / D1m≤-0.

41.

2. The optical imaging lens according to claim 1, wherein: A distance EP01 between the object side end surface of the lens barrel and the object side surface of the first spacer element in the extension direction of the optical axis and an effective focal length f1 of the first lens satisfy the following: -1.73≤f1 / EP01≤-1.

34.

3. The optical imaging lens according to claim 1, wherein: An air gap T12 between the first lens and the second lens on the optical axis, a center thickness CT1 of the first lens, and a maximum thickness CP1 of the first spacing element satisfy the following: 0.71≤T12 / (CT1+CP1)≤3.

13.

4. The optical imaging lens according to claim 1, wherein: 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 spacer element satisfy the following: -2.63≤R4*N2 / d2s≤-0.

61.

5. The optical imaging lens according to claim 1, wherein: The outer diameter D2m of the image side surface of the second spacer element, the curvature radius R6 of the image side surface of the third lens and the refractive index N3 of the third lens satisfy: -2.62≤D2m / (R6*N3)≤-1.

28.

6. The optical imaging lens according to claim 1, wherein: The center thickness CT3 of the third lens, the air interval T23 between the second lens and the third lens on the optical axis, and the maximum thickness CP2 of the second spacing element satisfy: 0.96≤CT3 / (T23+CP2)≤4.

33.

7. The optical imaging lens according to claim 1, wherein: The outer diameter D0s of the object side end surface of the lens barrel, the inner diameter d0s of the object side end surface of the lens barrel, the outer diameter D0m of the image side end surface of the lens barrel, and the inner diameter d0m of the image side end surface of the lens barrel satisfy the following relationship: 1.41≤(D0m-d0m) / (D0s-d0s)≤3.

70.

8. The optical imaging lens according to claim 1, wherein: The maximum height L of the lens barrel and the sum ΣCT of the center thicknesses of all lenses in the lens group satisfy the following: 1.64≤L / ΣCT≤2.

26.

9. The optical imaging lens according to claim 1, wherein: The curvature radius R1 of the object side surface of the first lens and the inner diameter d0s of the object side end surface of the lens barrel satisfy the following: -4.37≤R1 / d0s≤-0.

66.

10. The optical imaging lens according to any one of claims 1 to 9, 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 partially contacts the image side surface of the third lens. The effective focal length f3 of the third lens, the air gap T34 between the third lens and the fourth lens on the optical axis, and the distance EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element in the extension direction of the optical axis satisfy the following: 1.62≤f3 / (EP23+T34)≤14.

81.

11. The optical imaging lens according to any one of claims 1 to 9, 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 the image side portion of the third lens. The inner diameter d3s of the object side of the third spacer element and the curvature radius R7 of the object side of the fourth lens satisfy: -2.05≤R7 / d3s≤-0.

62.

12. The optical imaging lens according to any one of claims 1 to 9, characterized in that: The optical imaging lens satisfies at least one of the following: The first lens has negative optical power; The second lens has positive optical power; The third lens has positive refractive power.

13. The optical imaging lens according to any one of claims 1 to 9, characterized in that: The optical imaging lens satisfies at least one of the following: The object side surface of the first lens is a concave surface, and the image side surface of the first lens is a concave surface; The object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; The object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; The object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a convex surface.

Images