Optical lens

Abstract

The invention provides an optical lens. The optical lens comprises a lens barrel, and a lens group and a spacing element group which are assembled in the lens barrel, wherein the lens group sequentially comprises a first lens, a second lens, a third lens and a fourth lens from an object side to an image side along an optical axis; the spacing element group at least comprises a third spacing element; the third spacing element is positioned between the third lens and the fourth lens and is in contact with the object side surface part of the fourth lens; the effective focal length f of the optical lens, the effective focal length f3 of the third lens and the effective focal length f4 of the fourth lens meet the condition of 0.40 lt; f3 / f + f4 / f < = 0.75; the combined focal length f34 of the third lens and the fourth lens, the inner diameter d0m of the end face, closest to the image side, of the lens barrel and the inner diameter d3m of the image side face of the third spacing element meet the following formula:-0.05 lt; (d0m-d3m) / f < 34lt >; and 0.05%. The problem that stray light is serious due to the fact that an optical lens in the prior art meets the long-focus requirement is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical imaging devices, and more particularly, to an optical lens. Background Art

[0002] With the development of electronic products, the imaging system plays a crucial role in electronic products. Users have an increasing demand for photographing with electronic products and require electronic devices to meet diversified photo-taking needs. Most products from mainstream mid-range to top-of-the-line flagship models of various brands are equipped with main cameras and wide-angle lenses, but telephoto lenses have become exclusive to high-end flagship models. With the higher requirements for the actual application of the imaging system in smartphones, there is a trend of full popularization of telephoto lenses in the configuration of smartphones. However, in existing telephoto lenses, light is prone to large deflection at the end of the lens barrel, resulting in light being directed towards the end of the lens barrel and generating reflected stray light, which affects the imaging performance of the optical lens.

[0003] That is to say, existing optical lenses have the problem of serious stray light caused by meeting telephoto requirements. Summary of the Invention

[0004] The main object of the present invention is to provide an optical lens to solve the problem of serious stray light caused by meeting telephoto requirements in existing optical lenses.

[0005] To achieve the above object, according to one aspect of the present invention, there is provided an optical lens including 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 with negative optical power, and a fourth lens with positive optical power in sequence along the optical axis from the object side to the image side; the spacer element group includes at least a third spacer element, the third spacer element is located between the third lens and the fourth lens and is in partial contact with the object side surface of the fourth lens; the effective focal length f of the optical lens, the effective focal length f3 of the third lens, and the effective focal length f4 of the fourth lens satisfy: 0.40 < f3 / f + f4 / f ≤ 0.75; the combined focal length f34 of the third lens and the fourth lens, the inner diameter d0m of the end face of the lens barrel closest to the image side, and the inner diameter d3m of the image side surface of the third spacer element satisfy: -0.05 < (d0m - d3m) / f34 < 0.05.

[0006] According to another aspect of the present invention, an optical lens is provided. The optical lens includes a lens barrel, a lens group, and a spacer element group assembled in the lens barrel. The lens group sequentially includes a first lens, a second lens, a third lens with a negative focal power, and a fourth lens with a positive focal power along the optical axis from the object side to the image side. 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 partial contact with the object side surface of the third lens. The third spacer element is located between the third lens and the fourth lens and is in partial contact with the object side surface of the fourth lens. The following relationships are satisfied among the effective focal length f of the optical lens, the effective focal length f3 of the third lens, and the effective focal length f4 of the fourth lens: 0.40 < f3 / f + f4 / f ≤ 0.75; the following relationships are satisfied among the inner diameter d2m of the image side surface of the second spacer element, the inner diameter d3m of the image side surface of the third spacer element, the curvature radius R5 of the object side surface of the third lens, and the curvature radius R7 of the object side surface of the fourth lens: 0.55 < d2m / R5 + d3m / R7 < 0.85.

[0007] According to another aspect of the present invention, an optical lens is provided. The optical lens includes a lens barrel, a lens group, and a spacer element group assembled in the lens barrel. The lens group sequentially includes a first lens, a second lens, a third lens with a negative focal power, and a fourth lens with a positive focal power along the optical axis from the object side to the image side. 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 partial contact with the object side surface of the third lens. The third spacer element is located between the third lens and the fourth lens and is in partial contact with the object side surface of the fourth lens. The following relationships are satisfied among the inner diameter d0s of the end face of the lens barrel closest to the object side, the inner diameter d0m of the end face of the lens barrel closest to the image side, and the effective focal length f of the optical lens: 0.15 < (d0s - d0m) / f ≤ 0.25. The following relationships are satisfied among the curvature radius R4 of the image side surface of the second lens, the inner diameter d2s of the object side surface of the second spacer element, 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: 2.25 < R4 / d2s + R6 / d3s < 3.95.

[0008] Furthermore, the following relationship is satisfied among the height L of the lens barrel, the central thickness CT3 of the third lens, the air gap T34 on the optical axis between the third lens and the fourth lens, and the central thickness CT4 of the fourth lens: 2.20 ≤ L / (CT3 + T34 + CT4) < 2.65.

[0009] Furthermore, the following relationship is satisfied among the curvature radius R8 of the image side surface of the fourth lens, the outer diameter D0m of the end face of the lens barrel closest to the image side, and the inner diameter d0m of the end face of the lens barrel closest to the image side: -2.60 < R8 / (D0m - d0m) < -1.85.

[0010] Further, a curvature radius R7 of the object side surface of the fourth lens, a curvature radius R8 of the image side surface of the fourth lens, and an inner diameter d0s of the end surface of the lens barrel closest to the object side satisfy: -6.90<(R7+R8) / d0s<2.55.

[0011] Furthermore, the maximum thickness CP3 of the third spacing element along the extension direction of the optical axis and the air gap T34 between the third lens and the fourth lens on the optical axis satisfy: <CP3 / T34<0.25。

[0012] Furthermore, the outer diameter D0m of the end surface of the lens barrel closest to the image side, the maximum effective radius DT42 of the image side surface of the fourth lens, and the center thickness CT4 of the fourth lens satisfy: 9.85<(D0m-DT42) / CT4≤11.

[0013] Furthermore, the lens barrel has a bearing surface, the bearing surface bears against the lens closest to the image side of the lens group or the spacing element closest to the image side of the spacing element group, and the maximum distance Y between the end surface closest to the image side of the lens barrel and the bearing surface in the extension direction of the optical axis satisfies: 0.25 <Y<0.55。

[0014] Furthermore, the inner diameter d0s of the end surface of the lens barrel closest to the object side, the inner diameter d0m of the end surface of the lens barrel closest to the image side, and the effective focal length f of the optical lens satisfy the following relationship: 0.15<(d0s-d0m) / f≤0.25.

[0015] Further, a curvature radius R5 of the object-side surface of the third lens, a curvature radius R6 of the image-side surface of the third lens, and an inner diameter d3s of the object-side surface of the third spacing element satisfy: 1.95<(R5+R6) / d3s≤2.60.

[0016] Further, the spacer element group includes at least a second spacer element, the second spacer element is located between the second lens and the third lens and is in contact with the object side surface portion of the third lens;

[0017] The air gap T34 between the third lens and the fourth lens on the optical axis and the center thickness CT3 of the third lens satisfy: 1.00 <T34 / CT3<2.05;

[0018] The central thickness CT3 of the third lens, the interval EP23 between the image side surface of the second spacing element and the object side surface of the third spacing element in the direction of the optical axis extension satisfy: 2.50 <EP23 / CT3≤3.30。

[0019] Further, the spacer element group at least includes a second spacer element, which is located between the second lens and the third lens and is in partial contact with the object side surface of the third lens; the following relationship is satisfied among the maximum effective radius DT31 of the object side surface of the third lens, the maximum effective radius DT32 of the image side surface of the third lens, and the spacing EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element in the optical axis extension direction: 0.20 < (DT31 - DT32) / EP23 < 0.35.

[0020] Further, the spacer element group at least includes a second spacer element, which is located between the second lens and the third lens and is in partial contact with the object side surface of the third lens; the following relationship is satisfied between the effective focal length f3 of the third lens and the spacing EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element in the optical axis extension direction: -5.40 < f3 / EP23 < -3.25.

[0021] Further, the spacer element group at least includes a second spacer element, which is located between the second lens and the third lens and is in partial contact with the object side surface of the third lens; the following relationship is satisfied among the inner diameter d2m of the image side surface of the second spacer element, the inner diameter d3m of the image side surface of the third spacer element, the curvature radius R5 of the object side surface of the third lens, and the curvature radius R7 of the object side surface of the fourth lens: 0.55 < d2m / R5 + d3m / R7 < 0.85.

[0022] Further, the spacer element group at least includes a second spacer element, which is located between the second lens and the third lens and is in partial contact with the object side surface of the third lens; the following relationship is satisfied between the inner diameter d3s of the object side surface of the third spacer element and the inner diameter d2s of the object side surface of the second spacer element: 0.85 < d3s / d2s ≤ 0.95.

[0023] Applying the technical solution of the present invention, the optical lens includes a lens barrel, a lens group and a spacer element group assembled in the lens barrel. The lens group sequentially includes a first lens, a second lens, a third lens with negative optical power, and a fourth lens with positive optical power along the optical axis from the object side to the image side; the spacer element group at least includes a third spacer element, which is located between the third lens and the fourth lens and is in partial contact with the object side surface of the fourth lens; the following relationship is satisfied among the effective focal length f of the optical lens, the effective focal length f3 of the third lens, and the effective focal length f4 of the fourth lens: 0.40 < f3 / f + f4 / f ≤ 0.75; the following relationship is satisfied between the combined focal length f34 of the third lens and the fourth lens and the inner diameter d0m of the end face of the lens barrel closest to the image side and the inner diameter d3m of the image side surface of the third spacer element: -0.05 < (d0m - d3m) / f34 < 0.05.

[0024] The optical lens of the present application is composed of a lens barrel, four lenses and at least one spacer element. When the effective focal length f of the optical lens, the effective focal length f3 of the third lens, and the effective focal length f4 of the fourth lens satisfy 0.40 < f3 / f + f4 / f ≤ 0.75, by optimizing the focal length of the third lens, the focal length of the fourth lens, and the effective focal length of the optical lens, the refraction degree of light is controlled, so that the optical lens has the characteristics of a long focal length. Since the third lens and the fourth lens are located at the end of the optical lens and are the last two lenses that the light passes through when leaving the optical system, the light is easily deflected to the end of the lens barrel to form reflected stray light, resulting in serious stray light.

[0025] In order to reduce the stray light generated at the end of the lens barrel of the optical lens, the present application constrains (d0m - d3m) / f34 within a reasonable range to control the apertures of the third lens and the fourth lens, reduce the light deflected at large angles, and thus reduce the light incident on the inner wall of the lens barrel, minimizing the generation of stray light at the end of the lens barrel. At the same time, it ensures that the inner diameter d0m of the end face of the lens barrel closest to the image side is within a reasonable range to ensure the imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic 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:

[0027] Figure 1 Shows the dimension marking diagram of the optical lens of an optional embodiment of the present invention;

[0028] Figure 2 Shows the schematic structural diagram of the optical lens of Embodiment 1-1 of the present invention;

[0029] Figure 3 Shows the schematic structural diagram of the optical lens of Embodiment 1-2 of the present invention;

[0030] Figure 4 Shows the schematic structural diagram of the optical lens of Embodiment 1-3 of the present invention;

[0031] Figures 5 to 7 Respectively show the axial chromatic aberration, astigmatism curve and distortion curve of the optical lens of Embodiment 2 of the present invention;

[0032] Figure 8 Shows the schematic structural diagram of the optical lens of Embodiment 2-1 of the present invention;

[0033] Fig. 9 Shows the schematic structural diagram of the optical lens of Embodiment 2-2 of the present invention;

[0034] Fig.10A schematic structural diagram of an optical lens according to Embodiment 2-3 of the present invention is shown;

[0035] Figures 11 to 13 The axial chromatic aberration, astigmatism curve and distortion curve of the optical lens of the second embodiment of the present invention are respectively shown;

[0036] Fig.14 A schematic structural diagram of an optical lens according to Embodiment 3-1 of the present invention is shown;

[0037] Fig.15 A schematic structural diagram of an optical lens according to Embodiment 3-2 of the present invention is shown;

[0038] Fig.16 A schematic structural diagram of an optical lens according to Embodiment 3-3 of the present invention is shown;

[0039] Figures 17 to 19 The axial chromatic aberration, astigmatism curve and distortion curve of the optical lens of the third embodiment of the present invention are respectively shown;

[0040] Fig. 20 A stray light spot diagram of an optical lens of an optional embodiment of the present invention is shown;

[0041] Fig.21 A stray light path diagram of an optical lens of an example is shown;

[0042] Fig. 22 Shows Fig.21 The stray light spot diagram of the optical lens in the figure;

[0043] Fig.23 Another example of a stray light path diagram of an optical lens is shown;

[0044] Fig.24 Shows Fig.23 The stray light spot diagram of the optical 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 in the prior art that an optical lens has a serious stray light problem due to the long focus requirement, the present invention provides an optical lens.

[0052] like Figures 1 to 19As shown in the figure, the optical 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 with negative optical power, and a fourth lens with positive optical power in sequence along the optical axis from the object side to the image side. 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 is in partial contact with the object side surface of the fourth lens. The following relationships are satisfied among the effective focal length f of the optical lens, the effective focal length f3 of the third lens, and the effective focal length f4 of the fourth lens: 0.40 < f3 / f + f4 / f ≤ 0.75; the following relationship is satisfied between the combined focal length f34 of the third lens and the fourth lens, the inner diameter d0m of the end face of the lens barrel closest to the image side, and the inner diameter d3m of the image side surface of the third spacer element: -0.05 < (d0m - d3m) / f34 < 0.05.

[0053] The optical lens of the present application is composed of a lens barrel, four lenses and at least one spacer element. When 0.40 < f3 / f + f4 / f ≤ 0.75 is satisfied among the effective focal length f of the optical lens, the effective focal length f3 of the third lens, and the effective focal length f4 of the fourth lens, by optimizing the focal length of the third lens, the focal length of the fourth lens, and the effective focal length of the optical lens, the refraction degree of light is controlled, so that the optical lens has the characteristics of a long focal length. Since the third lens and the fourth lens are located at the end of the optical lens and are the last two lenses that the light passes through when leaving the optical system, the light is easily deflected to the end of the lens barrel to form reflected stray light, resulting in serious stray light.

[0054] In order to reduce the stray light generated at the end of the lens barrel of the optical lens, the present application constrains (d0m - d3m) / f34 within a reasonable range to control the apertures of the third lens and the fourth lens, reduce the light deflected at large angles, and further reduce the light incident on the inner wall of the lens barrel, so as to minimize the generation of stray light at the end of the lens barrel, and at the same time ensure that the inner diameter d0m of the end face of the lens barrel closest to the image side is within a reasonable range to ensure the imaging quality.

[0055] Table 1 below gives a comparison of the stray light results between an optional embodiment of the present application and the optical lens in the prior art.

[0056]

[0057]

[0058] Table 1

[0059] In addition, referring to Table 1 and Figure 20 to Figure 24 as shown in Fig. 20 shows the optical stray light spot diagram when f3 / f + f4 / f = 0.53 and (d0m - d3m) / f34 = -0.04. From Fig. 20As can be seen, there is no obvious stray light. Lenses 1 and 3 in Table 1 are optical lenses in the prior art. Fig.21 and Fig. 22 respectively show the stray light ray path diagram and the stray light spot diagram satisfying f3 / f + f4 / f = 0.53 and (d0m - d3m) / f34 = -0.13. Fig.23 and Fig.24 respectively show the stray light ray path diagram and the stray light spot diagram satisfying f3 / f + f4 / f = 0.53 and (d0m - d3m) / f34 = 0.12.

[0060] From Figure 20 to Figure 24 it can be known that when (d0m - d3m) / f34 = -0.04 is satisfied, the stray light energy weakens, the stray light is improved, and the performance is better. When (d0m - d3m) / f34 = -0.13 is satisfied, the stray light energy is stronger, the stray light has a greater impact on the imaging quality, and the performance is worse. When (d0m - d3m) / f34 = 0.12 is satisfied, the stray light energy is stronger, the stray light has a greater impact on the imaging quality, and the performance is worse. Thus, it can be seen that when (d0m - d3m) / f34 is in the range of -0.1 to 0.1, the improvement effect of the stray light of the optical lens is the best. Therefore, in this application, by restricting -0.05 < (d0m - d3m) / f34 < 0.05, the apertures of the third lens and the fourth lens are reasonably restricted to reduce the light rays with large-angle deflection, and then reduce the light rays hitting the inner wall of the lens barrel, minimizing the generation of stray light at the end of the lens barrel.

[0061] It should be noted that in this application, (d0m - d3m) / f34 is restricted within a reasonable range to control the apertures of the third lens and the fourth lens, and then to control and reduce the light rays with large-angle deflection, to solve the stray light problem brought about when f3 / f + f4 / f is in the range of 0.40 to 0.75. It is particularly applicable to the design of telephoto lenses. When (d0m - d3m) / f34 satisfies the above range, the purpose of reducing stray light can be achieved, and it does not depend on the optical power of the lens and the surface shape of the lens, while the optical power and the surface shape of the lens are further optimizations of the optical lens on this basis. Each lens can be positive or negative according to the design requirements of the actual optical system, and the surface shape of each lens can also be convex or concave according to the design requirements of the optical system, as long as the optical system satisfies: 0.40 < f3 / f + f4 / f ≤ 0.75; -0.05 < (d0m - d3m) / f34 < 0.05, the reduction of stray light can be achieved while meeting the telephoto requirements.

[0062] For example, the first lens has a positive focal power, the second lens has a positive focal power, the third lens has a negative focal power, and the fourth lens has a positive focal power. Another example is that the object side surface of the first lens is convex, the object side surface of the second lens is convex, the image side surface of the second lens is concave, the object side surface of the third lens is convex, the image side surface of the third lens is concave, and the image side surface of the fourth lens is convex. The stray light simulation of the optical lens can be carried out by software and / or tools such as LIGHTOOS, ASAP, etc. The optical lens in this application is simulated by ASAP. During the simulation using software and / or tools such as the above, the surface profiles of the respective lenses can be simulated according to the built-in surface profiles of the software and / or tools used and adjusted appropriately.

[0063] In some alternative embodiments, the height L of the lens barrel, the central thickness CT3 of the third lens, the air gap T34 between the third lens and the fourth lens on the optical axis, and the central thickness CT4 of the fourth lens satisfy: 2.20 ≤ L / (CT3 + T34 + CT4) < 2.65. By controlling L / (CT3 + T34 + CT4) within a reasonable range, the central thicknesses of the third lens and the fourth lens and the interval therebetween can be reasonably allocated, thereby optimizing the path of light passing through the entire optical system, reducing aberration, improving the imaging quality, and at the same time being beneficial to improving the assembly stability and reducing the performance fluctuations caused by external environmental differences. By restricting the central thicknesses of the third lens and the fourth lens and the interval therebetween, it is not only beneficial to the structural compactness but also beneficial to the smooth transition of light between the third lens and the fourth lens, reducing the light loss while meeting the telephoto performance and reducing the generation of stray light.

[0064] In some alternative embodiments, the radius of curvature R8 of the image side surface of the fourth lens, the outer diameter D0m of the end face of the lens barrel closest to the image side, and the inner diameter d0m of the end face of the lens barrel closest to the image side satisfy: -2.60 < R8 / (D0m - d0m) < -1.85. By restricting R8 / (D0m - d0m) within a reasonable range, it is beneficial to control the exit angle of light from the image side surface of the fourth lens, reducing the reflection of light to the end face of the lens barrel closest to the image side before reaching the imaging surface after exiting the fourth lens, further reducing the stray light generated at the end face of the lens barrel closest to the image side, further reducing the generation of stray light, and improving the imaging quality.

[0065] It should be noted that after the light exits the fourth lens and before reaching the imaging surface, it may be reflected by some structures in the electronic device to the end face of the lens barrel closest to the image side.

[0066] In some alternative embodiments, the radius of curvature R7 of the object side surface of the fourth lens, the radius of curvature R8 of the image side surface of the fourth lens, and the inner diameter d0s of the end face of the lens barrel closest to the object side satisfy: -6.90 < (R7 + R8) / d0s < 2.55. By restricting (R7 + R8) / d0s within a reasonable range, while ensuring the light input amount of the optical lens, the deflection angle of light within the fourth lens can also be ensured, so as to meet the performance requirements of long-distance telephoto imaging, reduce light loss, and thus improve the imaging quality.

[0067] In some alternative embodiments, the maximum thickness CP3 of the third spacer element in the extending direction along the optical axis and the air gap T34 between the third lens and the fourth lens on the optical axis satisfy: 0 < CP3 / T34 < 0.25. By restricting CP3 / T34 within a reasonable range, it is beneficial to the spatial control of the performance requirements of the air gap from the third lens to the fourth lens and its spacer element. The spacer element within a reasonable thickness range not only satisfies the edge light shielding but also ensures the requirements of the assembly structure stability. The appropriate air gap between the third lens and the fourth lens on the optical axis reserves sufficient space for the transition of light refraction change, meeting the actual requirements of telephoto imaging.

[0068] In some alternative embodiments, the outer diameter D0m of the end face of the lens barrel closest to the image side, the maximum effective radius DT42 of the image side surface of the fourth lens, and the central thickness CT4 of the fourth lens satisfy: 9.85 < (D0m - DT42) / CT4 ≤ 11. By restricting (D0m - DT42) / CT4 within a reasonable range, it can ensure that the light penetrates through the fourth lens and reaches the imaging surface at an appropriate angle and light density, ensuring the imaging quality and the performance requirements of the telephoto lens.

[0069] In some alternative embodiments, the lens barrel has a bearing surface, and the bearing surface abuts against the lens closest to the image side of the lens group or the spacer element closest to the image side of the spacer element group. The maximum distance Y in the extending direction along the optical axis between the end face of the lens barrel closest to the image side and the bearing surface satisfies: 0.25 < Y < 0.55. If the maximum distance Y in the extending direction along the optical axis between the end face of the lens barrel closest to the image side and the bearing surface is less than 0.25 mm, it will result in poor structural strength at the rear end of the lens barrel, which is not conducive to abutting against the fourth lens and is prone to the risk of deformation. If the maximum distance Y in the extending direction along the optical axis between the end face of the lens barrel closest to the image side and the bearing surface is greater than 0.55 mm, stray light is likely to be generated on the inner wall surface between the bearing surface and the end face of the lens barrel closest to the image side, and it also increases the weight of the optical lens, reducing the design freedom of the optical lens. By restricting the maximum distance Y in the extending direction along the optical axis between the end face of the lens barrel closest to the image side and the bearing surface within the range of 0.25 to 0.55 mm, while ensuring the structural strength at the rear end of the lens barrel, the risk of stray light is reduced, and at the same time, it is beneficial to the lightweight of the optical lens.

[0070] In some alternative embodiments, the inner diameter d0s of the end face of the lens barrel closest to the object side, the inner diameter d0m of the end face of the lens barrel closest to the image side, and the effective focal length f of the optical lens satisfy: 0.15 < (d0s - d0m) / f ≤ 0.25. By restricting (d0s - d0m) / f within a reasonable range, while ensuring the light flux, it is beneficial to reduce the field of view angle of the optical lens, which is conducive to the optical lens being able to capture distant scenes more clearly and achieve long focal length performance.

[0071] In some alternative embodiments, the radius of curvature R5 of the object side surface of the third lens, the radius of curvature R6 of the image side surface of the third lens, and the inner diameter d3s of the object side surface of the third spacer element satisfy: 1.95 < (R5 + R6) / d3s ≤ 2.60. By controlling (R5 + R6) / d3s within a reasonable range, it is beneficial to control the degree of deflection of light when entering the third lens and the degree of deflection of light when exiting the third lens, so as to ensure that light enters the fourth lens within the range of the inner diameter d3s of the object side surface of the third spacer element, which is conducive to reducing stray light of the light.

[0072] In some alternative embodiments, the spacer element group includes at least a second spacer element, the second spacer element is located between the second lens and the third lens and is in partial contact with the object side surface of the third lens; the air gap T34 between the third lens and the fourth lens on the optical axis and the central thickness CT3 of the third lens satisfy: 1.00 < T34 / CT3 < 2.05; the central thickness CT3 of the third lens and the interval EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element in the extending direction of the optical axis satisfy: 2.50 < EP23 / CT3 ≤ 3.30. By controlling the air gap T34 between the third lens and the fourth lens on the optical axis, the central thickness CT3 of the third lens, and the interval EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element in the extending direction of the optical axis within a reasonable range, while the light smoothly transitions between the third lens and the fourth lens, it is beneficial to control the thickness ratio of the third lens and avoid the appearance of poor appearance and abnormal stray light during the actual processing, and further improve the overall imaging quality of the optical lens.

[0073] In some alternative embodiments, the spacer element group at least includes a second spacer element, the second spacer element is located between the second lens and the third lens and is in partial contact with the object side surface of the third lens; the maximum effective radius DT31 of the object side surface of the third lens, the maximum effective radius DT32 of the image side surface of the third lens, and the interval EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element in the optical axis extension direction satisfy: 0.20 < (DT31 - DT32) / EP23 < 0.35. By controlling (DT31 - DT32) / EP23 within a reasonable range, the shape and edge thickness of the third lens can be effectively controlled, which is beneficial to the processing and forming of the third lens. At the same time, by controlling the maximum effective radii of the object side surface and the image side surface of the third lens, the optical performance of the optical lens can also be taken into account, which is beneficial to reducing optical distortion and the thickness sensitivity of the lens, and further achieving the purpose of correcting field curvature.

[0074] In some alternative embodiments, the spacer element group at least includes a second spacer element, the second spacer element is located between the second lens and the third lens and is in partial contact with the object side surface of the third lens; the effective focal length f3 of the third lens and the interval EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element in the optical axis extension direction satisfy: -5.40 < f3 / EP23 < -3.25. By controlling f3 / EP23 within a reasonable range, it helps to reduce imaging quality problems such as aberrations and distortions caused by improper element spacing near the third lens and mismatch with the focal length of the third lens. At the same time, it can ensure that light can pass through the optical lens in the expected manner and form a clear and accurate image on the imaging surface.

[0075] In some alternative embodiments, the inner diameter d2m of the image side surface of the second spacer element, the inner diameter d3m of the image side surface of the third spacer element, the curvature radius R5 of the object side surface of the third lens, and the curvature radius R7 of the object side surface of the fourth lens satisfy: 0.55 < d2m / R5 + d3m / R7 < 0.85. By controlling d2m / R5 + d3m / R7 within a reasonable range, it is beneficial for light to smoothly enter the object side surface of the third lens and the object side surface of the fourth lens, thereby reducing light loss and improving imaging quality. At the same time, it is beneficial to reasonably control the propagation path and light distribution of light between the third lens and the fourth lens to meet the performance requirements of telephoto imaging.

[0076] In some alternative embodiments, the spacer element group at least includes a second spacer element, which is located between the second lens and the third lens and is in partial contact with the object-side surface of the third lens; the inner diameter d3s of the object-side surface of the third spacer element and the inner diameter d2s of the object-side surface of the second spacer element satisfy: 0.85 < d3s / d2s ≤ 0.95. By controlling d3s / d2s within a reasonable range, it is ensured that marginal rays pass through the third lens and the third spacer element at an appropriate angle, so as to ensure that marginal rays participate in imaging, which is conducive to improving the imaging quality of the optical lens.

[0077] In addition, in another alternative embodiment of the present application, an optical lens is further provided. The optical lens includes a lens barrel, as well as a lens group and a spacer element group assembled in the lens barrel. The lens group sequentially includes a first lens with a positive focal power, a second lens with a positive focal power, a third lens with a negative focal power, and a fourth lens with a positive focal power along the optical axis from the object side to the image side. The object-side surface of the first lens is convex, the object-side surface of the second lens is convex, the image-side surface of the second lens is concave, the object-side surface of the third lens is convex, the image-side surface of the third lens is concave, and the image-side surface of the fourth lens is convex; the spacer element group at least 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 is in partial contact with the object-side surface of the third lens, and the third spacer element is located between the third lens and the fourth lens and is in partial contact with the object-side surface of the fourth lens; the effective focal length f of the optical lens, the effective focal length f3 of the third lens, and the effective focal length f4 of the fourth lens satisfy: 0.40 < f3 / f + f4 / f ≤ 0.75; the inner diameter d2m of the image-side surface of the second spacer element, the inner diameter d3m of the image-side surface of the third spacer element, the curvature radius R5 of the object-side surface of the third lens, and the curvature radius R7 of the object-side surface of the fourth lens satisfy: 0.55 < d2m / R5 + d3m / R7 < 0.85.

[0078] The optical lens of the present application is composed of a lens barrel, four lenses and at least one spacer element. When the effective focal length f of the optical lens, the effective focal length f3 of the third lens, and the effective focal length f4 of the fourth lens satisfy 0.40 < f3 / f + f4 / f ≤ 0.75, by optimizing the focal lengths of the third lens, the fourth lens and the effective focal length of the optical lens, the optical lens has the characteristics of a long focal length. Since the third lens and the fourth lens are located at the end of the optical lens and are the last two lenses that the light passes through when leaving the optical system, the light is easily deflected to the end of the lens barrel to form reflected stray light, resulting in serious stray light. In order to reduce the stray light generated at the end of the lens barrel of the optical lens, the present application constrains d2m / R5 + d3m / R7 within a reasonable range to control the deflection angle of the light when entering the object side of the third lens and the object side of the fourth lens, reduce the deflection of the large-angle light, ensure that the light passes through the second spacer element and the third spacer element smoothly, reduce the reflected stray light generated at the spacer element and the inner wall of the lens barrel, and improve the imaging quality. At the same time, it is beneficial to reasonably control the propagation path and light distribution of the light between the third lens and the fourth lens to meet the performance requirements of long focal length imaging.

[0079] In addition, in another alternative embodiment of the present application, an optical lens is further provided. The optical 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 a positive optical power, a second lens with a positive optical power, a third lens with a negative optical power, and a fourth lens with a positive optical power in sequence along the optical axis from the object side to the image side. The object side of the first lens is convex, the object side of the second lens is convex, the image side of the second lens is concave, the object side of the third lens is convex, the image side of the third lens is concave, and the image side of the fourth lens is convex; 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 partial contact with the object side of the third lens. The third spacer element is located between the third lens and the fourth lens and is in partial contact with the object side of the fourth lens; the inner diameter d0s of the end face of the lens barrel closest to the object side, the inner diameter d0m of the end face of the lens barrel closest to the image side, and the effective focal length f of the optical lens satisfy: 0.15 < (d0s - d0m) / f ≤ 0.25. The radius of curvature R4 of the image side of the second lens, the inner diameter d2s of the object side of the second spacer element, the radius of curvature R6 of the image side of the third lens, and the inner diameter d3s of the object side of the third spacer element satisfy: 2.25 < R4 / d2s + R6 / d3s < 3.95.

[0080] 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 d0s of the end face of the lens barrel closest to the object side, the inner diameter d0m of the end face of the lens barrel closest to the image side and the effective focal length f of the optical lens satisfy: 0.15<(d0s-d0m) / f≤0.25, it is beneficial to reduce the field angle of the optical lens while ensuring the luminous flux, which is beneficial for the optical lens to capture the distant scene more clearly and achieve telephoto performance. However, due to the large value of d0s-d0m, it is easy to cause the light to be deflected at a large angle in the lens group, causing multiple reflections and causing serious stray light. In order to reduce the stray light generated in the lens group, the present application constrains R4 / d2s+R6 / d3s within a reasonable range to control the deflection angle of the light in the middle lens, so that the light is smoothly transferred between the second lens and the third lens, reducing the large angle deflection at the position of the middle lens, reducing the light from generating multiple reflections of stray light at the inner wall of the lens barrel, and improving the imaging quality.

[0081] Of course, this embodiment may also include other parameter formulas in the above embodiment, which will not be described one by one here.

[0082] Optionally, the optical lens may further include a protective glass for protecting a photosensitive element located on the imaging surface.

[0083] 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.

[0084] 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.

[0085] Figure 1 A schematic diagram of the dimension marking of an optical lens of the present application is shown. Figure 1 Parameters such as d2s, d2m, d3s, d3m, d0s, d0m, D0m, CP3, EP23, L, and Y 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 the specific embodiments are described later.

[0086] 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.

[0087] It should be noted that in the following embodiment 1, there are three examples of embodiment 1-1, embodiment 1-2, and embodiment 1-3; in embodiment 2, there are three examples of embodiment 2-1, embodiment 2-2, and embodiment 2-3; and in embodiment 3, there are three examples of embodiment 3-1, embodiment 3-2, and embodiment 2-3. In the three examples of the same embodiment, the parameters such as the radius of curvature, center thickness, and spacing distances between lenses of the optical 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 structure for imaging is the same, but the auxiliary structure for imaging is different.

[0088] It should be noted that any one of the following embodiments 1 to 3 is applicable to all embodiments of the present application.

[0089] Embodiment 1

[0090] like Figures 2 to 7 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.

[0091] like Figures 2 to 4 As shown, the optical 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 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.

[0092] like Figure 2Shown is the structural representation of the optical lens of embodiment 1-1. In this example, 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 of the first spacing element P1 partially abuts against the image side surface S2 of the first lens, and the object side surface and the image side surface of the first auxiliary spacing element P1b partially abut against the image side surface S3 of the first spacing element P1 and the object 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, respectively. The image side surface S6 of the third lens partially abuts against the bearing surface of the lens barrel P0.

[0093] like Figure 3 , which is a schematic diagram of the structure of the optical lens of Example 1-2. In Example 1-2, the optical lens further includes a second auxiliary spacing element P1c, and the object side surface and image side surface of the second auxiliary spacing element P1c are respectively abutted against the image side surface of the first auxiliary spacing element P1b and the object side surface S3 of the second lens. The abutment manner of other spacing elements is similar to that of Example 1-1, and the relevant description in Example 1-1 may be referred to, and no further description is given here.

[0094] like Figure 4 , which is a schematic diagram of the structure of the optical lens of Example 1-3. In Example 1-3, the abutting manner of each spacing element is similar to that of Example 1-1, and the relevant description in Example 1-1 may be referred to, and will not be repeated here.

[0095] 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 2. (Unit: mm)

[0096] Parameters / Examples 1-1 1-2 1-3 d2s 5.14 5.06 5.12 d2m 5.10 5.02 5.08 d3s 4.43 4.50 4.60 d3m 4.39 4.46 4.56 d0s 7.98 8.20 7.85 d0m 4.78 4.54 4.38 D0m 8.84 8.64 8.44 EP23 1.31 1.19 1.17 CP3 0.01 0.01 0.06 L 4.17 4.07 4.22 Y 0.40 0.28 0.45

[0097] Table 2

[0098] In the first embodiment, the first lens has positive power, the object side surface S1 of the first lens is convex, and the image side surface S2 of the first lens is convex. The second lens has positive power, the object side surface S3 of the second lens is convex, and the image side surface S4 of the second lens is concave. The third lens has negative power, the object side surface S5 of the third lens is convex, and the image side surface S6 of the third lens is concave; the fourth lens has positive power, the object side surface S7 of the fourth lens is convex, and the image side surface S8 of the fourth lens is convex.

[0099] Table 3 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.

[0100]

[0101] Table 3

[0102] In the first embodiment, the object side surface and the image side surface of the second lens E2 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:

[0103]

[0104] 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 4 gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 that can be used for each aspheric mirror surface S3-S8 in Example 1.

[0105]

[0106]

[0107] Table 4

[0108] 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.

[0109] according to Figures 5 to 7 It can be seen that the optical lens provided in the first embodiment can achieve good imaging quality.

[0110] Embodiment 2

[0111] like Figures 8 to 13 As shown, the optical lens of the second embodiment is described. Figure 8 The structure diagram of the optical lens of Example 2-1 is shown. Fig. 9 FIG. 2 shows a schematic structural diagram of an optical lens of Example 2-2. Fig.10 A schematic structural diagram of the optical lens of Example 2-3 is shown.

[0112] like Figures 8 to 10As shown, the optical lens includes a lens barrel P0, four lenses and multiple spacer elements. The lens barrel P0 includes a first lens E1, a second auxiliary spacer element P1c, 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.

[0113] like Figure 8 2-1, is the structural diagram of the optical lens of embodiment 2-1. In this example, 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 of the first auxiliary spacing element P1b, respectively, and the image side surface of the second auxiliary spacing element P1c partially abuts against the image side surface S3 of the first auxiliary spacing element P1b and the object 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, respectively. The image side surface S6 of the third lens partially abuts against the bearing surface of the lens barrel P0.

[0114] like Fig. 9 As shown in FIG. 2 , it is a schematic diagram of the structure of the optical lens of Example 2-2. Fig.10 , which is a schematic diagram of the structure of the optical lens of Example 2-3. In Example 2-2 and Example 2-3, the abutment 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.

[0115] 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 5. (Unit: mm)

[0116]

[0117]

[0118] Table 5

[0119] In the second embodiment, the first lens has positive power, the object side surface S1 of the first lens is convex, and the image side surface S2 of the first lens is a plane. The second lens has positive power, the object side surface S3 of the second lens is convex, and the image side surface S4 of the second lens is concave. The third lens has negative power, the object side surface S5 of the third lens is convex, and the image side surface S6 of the third lens is concave; the fourth lens has positive power, the object side surface S7 of the fourth lens is convex, and the image side surface S8 of the fourth lens is convex.

[0120] Table 6 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.

[0121]

[0122] Table 6

[0123] Table 7 shows the coefficients of the higher order terms of each aspheric mirror surface that can be used in Example 2, 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.

[0124]

[0125]

[0126] Table 7

[0127] Fig.11 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.12 The astigmatism curve of the optical lens of Example 2 is shown, which represents the meridional image curvature and the sagittal image curvature. Fig.13 The distortion curve of the optical lens of the second embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles.

[0128] according to Figures 11 to 13 It can be seen that the optical lens provided in the second embodiment can achieve good imaging quality.

[0129] Embodiment 3

[0130] like Figures 14 to 19 As shown, the optical lens of embodiment 3 is described. Fig.14 The structure diagram of the optical lens of Example 3-1 is shown. Fig.15 FIG. 3 is a schematic diagram showing the structure of the optical lens of Example 3-2. Fig.16 A schematic structural diagram of the optical lens of Example 3-3 is shown.

[0131] like Figures 14 to 16 As shown, the optical 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 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.

[0132] like Fig.14, it is the structural representation of the optical lens of embodiment 3-1. In this example, 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 of the first spacing element P1 partially abuts against the image side surface S2 of the first lens, and the object side surface and the image side surface of the first auxiliary spacing element P1b partially abut against the image side surface S3 of the first spacing element P1 and the object 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, respectively. The image side surface S6 of the third lens partially abuts against the bearing surface of the lens barrel P0.

[0133] like Fig.15 , which is a schematic diagram of the structure of the optical lens of Example 3-2. In Example 3-2, the supporting and abutting manner of each spacing element is similar to that of Example 3-1, and the relevant description in Example 3-1 may be referred to, and will not be repeated here.

[0134] like Fig.16 , which is a schematic diagram of the structure of the optical lens of Example 3-3. In Examples 3-2 and 3-3, the optical lens further includes a second auxiliary spacing element P1c, and the object side surface and image side surface of the second auxiliary spacing element P1c are respectively aligned with the image side surface of the first auxiliary spacing element P1b and the object side surface S3 of the second lens. The supporting and abutting manner of other spacing elements is similar to that of Example 1-1, and reference may be made to the relevant description in Example 1-1, which will not be repeated here.

[0135] 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 8. (Unit: mm)

[0136] Parameters / Examples 3-1 3-2 3-3 d2s 5.37 5.39 5.25 d2m 5.33 5.35 5.21 d3s 4.74 4.76 4.97 d3m 4.70 4.72 4.93 d0s 7.95 8.14 7.70 d0m 4.80 4.70 4.86 D0m 8.78 8.68 8.50 EP23 1.14 1.01 1.26 CP3 0.07 0.01 0.02 L 4.01 4.04 3.85 Y 0.40 0.43 0.34

[0137] Table 8

[0138] In the third embodiment, the first lens has positive power, the object side surface S1 of the first lens is convex, and the image side surface S2 of the first lens is convex. The second lens has positive power, the object side surface S3 of the second lens is convex, and the image side surface S4 of the second lens is concave. The third lens has negative power, the object side surface S5 of the third lens is convex, and the image side surface S6 of the third lens is concave; 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.

[0139] Table 9 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.

[0140]

[0141] Table 9

[0142] Table 10 shows the coefficients of the higher order terms of each aspheric mirror surface that can be used in Example 3, wherein each aspheric surface shape 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 to fourth lenses are all aspheric surfaces.

[0143]

[0144]

[0145] Table 10

[0146] Fig.17 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.18 The astigmatism curve of the optical lens of Example 3 is shown, which represents the meridional image curvature and the sagittal image curvature. Fig.19 The distortion curve of the optical lens of the third embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles.

[0147] according to Figures 17 to 19 It can be seen that the optical lens provided in the third embodiment can achieve good imaging quality.

[0148] In summary, the optical lenses of Embodiments 1 to 3 respectively satisfy the relationship shown in Table 11.

[0149] Conditional / Example 1-1 1-2 1-3 2-1 2-2 2-3 3-1 3-2 3-3 f3 / f+f4 / f 0.53 0.53 0.53 0.42 0.42 0.42 0.75 0.75 0.75 (d0m-d3m) / f34 -0.04 -0.01 0.02 -0.02 -0.02 0.00 -0.01 0.00 0.01 L / (CT3+T34+CT4) 2.51 2.45 2.54 2.52 2.61 2.54 2.30 2.31 2.20 T34 / CT3 1.49 1.49 1.49 1.04 1.04 1.04 2.04 2.04 2.04 EP23 / CT3 3.09 2.81 2.76 2.77 2.73 2.54 2.98 2.65 3.30 (DT31-DT32) / EP23 0.21 0.24 0.24 0.25 0.25 0.27 0.28 0.31 0.25 R8 / (D0m-d0m) -2.22 -2.19 -2.22 -2.34 -2.57 -2.33 -1.89 -1.89 -2.07 (R7+R8) / d0s 2.50 2.43 2.54 0.88 0.86 0.88 -6.68 -6.52 -6.89 CP3 / T34 0.02 0.02 0.09 0.24 0.17 0.13 0.09 0.02 0.02 f3 / EP23 -3.74 -4.12 -4.18 -3.27 -3.32 -3.57 -4.80 -5.39 -4.33 d2m / R5+d3m / R7 0.77 0.76 0.77 0.81 0.82 0.83 0.61 0.61 0.59 (D0m-DT42) / CT4 11.00 10.67 10.34 10.26 9.89 10.08 10.95 10.78 10.48 d3s / d2s 0.86 0.89 0.90 0.87 0.90 0.86 0.88 0.88 0.95 Y 0.40 0.28 0.45 0.44 0.51 0.47 0.40 0.43 0.34 (d0s-d0m) / f 0.22 0.25 0.24 0.22 0.22 0.23 0.22 0.24 0.19 R4 / d2s+R6 / d3s 2.85 2.87 2.84 3.93 3.93 3.87 2.29 2.28 2.31

[0150] Table 11

[0151] Table 12 shows the effective focal length of each lens of the optical lens of Examples 1 to 3 (unit: mm).

[0152]

[0153]

[0154] Table 12

[0155] 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 lens described above.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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 invention comprises 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 along the optical axis, a first lens, a second lens, a third lens with negative optical power, and a fourth lens with positive optical power; The spacer element group includes at least a third spacer element, the third spacer element is located between the third lens and the fourth lens and is in contact with the object side surface portion of the fourth lens; The effective focal length f of the optical lens, the effective focal length f3 of the third lens, the effective focal length f4 of the fourth lens f4 satisfies: 0.40 <f3 / f+f4 / f≤0.75; The combined focal length f34 of the third lens and the fourth lens, the inner diameter d0m of the end surface of the lens barrel closest to the image side, and the inner diameter d3m of the image side surface of the third spacing element satisfy: -0.05<(d0m-d3m) / f34<0.

05.

2. The optical lens according to claim 1, characterized in that: The height L of the lens barrel, the center thickness CT3 of the third lens, the air gap T34 between the third lens and the fourth lens on the optical axis, and the center thickness CT4 of the fourth lens satisfy: 2.20≤'L / (CT3+T34+CT4)<2.

65.

3. The optical lens according to claim 1, characterized in that: The curvature radius R8 of the image side surface of the fourth lens, the outer diameter D0m of the end surface of the lens barrel closest to the image side, and the inner diameter d0m of the end surface of the lens barrel closest to the image side satisfy: -2.60 <R8 / (D0m-d0m)<-1.85。 4. The optical lens according to claim 1, characterized in that: The curvature radius R7 of the object side surface of the fourth lens, the curvature radius R8 of the image side surface of the fourth lens, and the inner diameter d0s of the end surface of the lens barrel closest to the object side satisfy: -6.90<(R7+R8) / d0s<2.

55.

5. The optical lens according to claim 1, characterized in that: The maximum thickness CP3 of the third spacing element along the extension direction of the optical axis and the air gap T34 between the third lens and the fourth lens on the optical axis satisfy: <CP3 / T34<0.25。 6. The optical lens according to claim 1, characterized in that: The outer diameter D0m of the end surface of the lens barrel closest to the image side, the maximum effective radius DT42 of the image side surface of the fourth lens, and the center thickness CT4 of the fourth lens satisfy the following: 9.85<(D0m-DT42) / CT4≤11.

7. The optical lens according to claim 1, characterized in that: The lens barrel has a bearing surface, the bearing surface bears against the lens of the lens group closest to the image side or the spacing element of the spacing element group closest to the image side, and the maximum distance Y between the end surface of the lens barrel closest to the image side and the bearing surface along the extension direction of the optical axis satisfies: 0.25 <Y<0.55。 8. The optical lens according to claim 1, characterized in that: The inner diameter d0s of the end surface of the lens barrel closest to the object side, the inner diameter d0m of the end surface of the lens barrel closest to the image side, and the effective focal length f of the optical lens satisfy the following relationship: 0.15<(d0s-d0m) / f≤0.

25.

9. The optical lens according to claim 1, characterized in that: A curvature radius R5 of the object side surface of the third lens, a curvature radius R6 of the image side surface of the third lens, and an inner diameter d3s of the object side surface of the third spacing element satisfy the following relationship: 1.95<(R5+R6) / d3s≤2.

60.

10. The optical lens according to any one of claims 1 to 9, characterized in that: The spacer element group includes at least a second spacer element, the second spacer element is located between the second lens and the third lens and is in contact with the object side surface portion of the third lens; The air gap T34 between the third lens and the fourth lens on the optical axis and the center thickness CT3 of the third lens satisfy: 1.00 <T34 / CT3<2.05; The center thickness CT3 of the third lens, the interval EP23 between the image side surface of the second spacing element and the object side surface of the third spacing element in the extending direction of the optical axis satisfy: 2.50 <EP23 / CT3≤3.30。 11. The optical lens according to any one of claims 1 to 9, characterized in that: The spacer element group includes at least a second spacer element, which is located between the second lens and the third lens and partially contacts the object side surface of the third lens; the maximum effective radius DT31 of the object side surface of the third lens, the maximum effective radius DT32 of the image side surface of the third lens, and the interval 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: 0.20<(DT31-DT32) / EP23<0.

35.

12. The optical lens according to any one of claims 1 to 9, characterized in that: The spacer element group includes at least a second spacer element, the second spacer element is located between the second lens and the third lens and partially contacts the object side surface of the third lens; the effective focal length f3 of the third lens, the image side surface of the second spacer element and the object side surface of the third spacer element in the extending direction of the optical axis satisfy the following interval EP23: -5.40 <f3 / EP23<-3.25。 13. The optical lens according to any one of claims 1 to 9, characterized in that: The spacer element group includes at least a second spacer element, the second spacer element is located between the second lens and the third lens and partially contacts the object side surface of the third lens, and the inner diameter d2m of the image side surface of the second spacer element, the inner diameter d3m of the image side surface of the third spacer element, the curvature radius R5 of the object side surface of the third lens, and the curvature radius R7 of the object side surface of the fourth lens satisfy the following conditions: 0.55 <d2m / R5+d3m / R7<0.85。 14. The optical lens according to any one of claims 1 to 9, characterized in that: The spacer element group includes at least a second spacer element, the second spacer element is located between the second lens and the third lens and partially contacts the object side surface of the third lens; the inner diameter d3s of the object side surface of the third spacer element and the inner diameter d2s of the object side surface of the second spacer element satisfy: 0.85 <d3s / d2s≤0.95。

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