Optical lens

Abstract

The application provides an optical lens, comprising five lenses, sequentially comprising, along an optical axis from an object side to an imaging surface: a first lens with positive refractive power, the object side of the first lens being a convex surface, and the image side of the first lens being a plane; a second lens with refractive power; a third lens with positive refractive power, the image side of the third lens being a convex surface; a fourth lens with negative refractive power, the object side of the fourth lens being a concave surface, and the image side of the fourth lens being a concave surface; and a fifth lens with positive refractive power, the object side of the fifth lens being a convex surface, and the image side of the fifth lens being a plane or a concave surface; wherein the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 1.35°<FOV / Fno<1.75°; and the back focal length BFL of the optical lens and the total track length TTL of the optical lens satisfy: 0.4<BFL / TTL<0.6. The optical lens provided by the application can improve the imaging quality of the optical lens, reduce aberration, and improve the imaging quality of the optical lens through specific surface shape matching and reasonable refractive power distribution.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of imaging lenses, in particular to an optical lens. BACKGROUND

[0002] The gun sight is a special tool for hunting or shooting sports, and the application environment is complex, which requires strong environmental adaptability. In the highly competitive form, the ordinary lens cannot meet the needs, and the sighting lens often needs to be installed on the gun. The shooting environment also occurs at night or in a dark area. At present, many gun sighting lenses have a blurred situation in poor light conditions, and most of the lenses can well image the objects aimed at in the close view, but the imaging of distant targets is poor, and cannot take into account high-pixel long-distance imaging. When aiming at distant objects, the problem of not being able to highlight the main body occurs. SUMMARY

[0003] In view of the above problems, the purpose of the present application is to provide an optical lens, which has the advantages of excellent imaging quality.

[0004] The technical scheme adopted by the present application is:

[0005] An optical lens comprises five lenses, which are sequentially arranged along the optical axis from the object side to the imaging surface and comprise:

[0006] The first lens has positive refractive power, the object side surface is a convex surface, and the image side surface is a plane;

[0007] The second lens has refractive power;

[0008] The third lens has positive refractive power, and the image side surface is a convex surface;

[0009] The fourth lens has negative refractive power, the object side surface is a concave surface, and the image side surface is a concave surface;

[0010] The fifth lens has positive refractive power, the object side surface is a convex surface, and the image side surface is a plane or a concave surface;

[0011] Wherein, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 1.35°<FOV / Fno<1.75°; the back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0.4<BFL / TTL<0.6; the image side surface curvature radius R8 of the fourth lens and the object side surface curvature radius R9 of the fifth lens satisfy: -0.4<(R8-R9) / (R8+R9)≤0.

[0012] It is further preferred that the effective focal length f of the optical lens satisfies: 80mm < f < 100mm; and the chief ray angle of incidence CRA at the maximum image height of the optical lens satisfies: 2.7° < CRA < 5.5°.

[0013] It is further preferred that the total track length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1 < TTL / f < 1.35; and the total track length TTL of the optical lens and the real image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 7.1 < TTL / IH < 11.1.

[0014] It is further preferred that the real image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 0.55 < IH / EPD < 0.7; and the total track length TTL of the optical lens, the real image height IH corresponding to the maximum field of view angle of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 3.7 / ° < TTL / IH / FOV < 6 / °.

[0015] It is further preferred that the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -0.3 < f4 / f < -0.1; and the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 0 < (R7+R8) / (R7-R8) < 0.8.

[0016] It is further preferred that the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.2 < f5 / f < 0.5; and the effective focal length f of the optical lens and the radius of curvature R9 of the object side surface of the fifth lens satisfy: 0.15 < R9 / f < 0.35.

[0017] It is further preferred that the combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f45 of the fourth lens and the fifth lens satisfy: -1 < f123 / f45 < -0.6; and the half radius of the light passing d1 of the object side surface of the first lens and the half radius of the light passing d10 of the image side surface of the fifth lens satisfy: 1.15 < d1 / d10 < 1.8.

[0018] It is further preferred that the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: -10.6 < f3 / f4 < -1.5; and the radius of curvature R6 of the image side surface of the third lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: -4.2 < R6 / R8 < -2.1.

[0019] It is further preferred that the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -0.75 < f4 / f5 < -0.4; the image-side curvature radius R8 of the fourth lens and the object-side curvature radius R9 of the fifth lens satisfy: 0.7 < R8 / R9 < 1.1.

[0020] It is further preferred that the focal length f2 of the second lens and the object-side curvature radius R3 of the second lens satisfy: 0.2 < f2 / R3 < 0.6; the focal length f2 of the second lens and the image-side curvature radius R4 of the second lens satisfy: -1.2 < f2 / R4 < -0.8.

[0021] It is further preferred that the object-side curvature radius R7 of the fourth lens and the image-side curvature radius R8 of the fourth lens satisfy: -4.5 < R7 / R8 < -1; the object-side curvature radius R7 of the fourth lens, the central thickness CT4 of the fourth lens and the image-side curvature radius R8 of the fourth lens satisfy: -4.8 < (R7-CT4) / R8 < -1.35.

[0022] Compared with the prior art, the optical lens provided by the application has high relative luminance, the object-side surface of the first lens is convex, which helps to converge incident light and reduce the head lens aperture, thereby facilitating the miniaturization of the head; meanwhile, the lens has long-focus characteristics, can better present large local details, and makes the picture more concentrated and compact; the imaging quality of the optical lens is improved, the aberration is reduced, and the imaging quality of the optical lens is improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the following drawings, in which:

[0024] Figure 1 FIG. 1 is a structural schematic diagram of an optical lens according to an embodiment of the present application.

[0025] Figure 2 FIG. 5 is an F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 1 of the present application.

[0026] Figure 3 FIG. 7 is an axial aberration curve diagram of the optical lens in Embodiment 1 of the present application.

[0027] Figure 4 FIG. 9 is a curve diagram of the sagittal color aberration of the optical lens in Embodiment 1 of the present application.

[0028] Figure 5 FIG. 11 is an MTF curve diagram of the optical lens in Embodiment 1 of the present application.

[0029] Figure 6 Relative illuminance curve of the optical lens in Embodiment 1 of the present application.

[0030] Figure 7 Structural schematic diagram of the optical lens in Embodiment 2 of the present application.

[0031] Figure 8 F-Tan(Theta) distortion curve of the optical lens in Embodiment 2 of the present application.

[0032] Figure 9 Axial aberration curve of the optical lens in Embodiment 2 of the present application.

[0033] Figure 10 Decentration curve of the optical lens in Embodiment 2 of the present application.

[0034] Figure 11 MTF curve of the optical lens in Embodiment 2 of the present application.

[0035] Figure 12 Relative illuminance curve of the optical lens in Embodiment 2 of the present application.

[0036] Figure 13 Structural schematic diagram of the optical lens in Embodiment 3 of the present application.

[0037] Figure 14 F-Tan(Theta) distortion curve of the optical lens in Embodiment 3 of the present application.

[0038] Figure 15 Axial aberration curve of the optical lens in Embodiment 3 of the present application.

[0039] Figure 16 Decentration curve of the optical lens in Embodiment 3 of the present application.

[0040] Figure 17 MTF curve of the optical lens in Embodiment 3 of the present application.

[0041] Figure 18 Relative illuminance curve of the optical lens in Embodiment 3 of the present application.

[0042] The following specific embodiments will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0043] For a better understanding of the present application, various aspects of the present application will be presented in more detail by referring to the attached drawings. It should be understood that these detailed descriptions are merely descriptive of the embodiments of the present application and are not intended in any way to limit the scope of the present application. Throughout the specification, like drawing reference numerals refer to like elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0044] It should be noted that the expressions first, second, third and the like in this specification are used only to distinguish one feature from another feature, and do not indicate any limitation of the features. Thus, the first lens discussed below can also be referred to as a second lens or a third lens without departing from the teachings of the present application.

[0045] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for the sake of explanation. Specifically, the shape of the spherical surface or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical surface or aspherical surface is not limited to the shape of the spherical surface or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0046] In this specification, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the image plane is referred to as the image side surface of the lens.

[0047] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. Furthermore, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the word "exemplary" is intended to mean an example or an illustration.

[0048] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0049] It should be noted that the embodiments and the features in the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0050] The optical lens provided by the embodiment of the present application comprises five lenses, which are sequentially arranged along the optical axis from the object side to the imaging surface as the first lens, the second lens, the third lens, the fourth lens and the fifth lens.

[0051] In some embodiments, the first lens can have a positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a plane. The second lens can have a positive focal power or a negative focal power, the object side surface of which can be a concave surface or a convex surface, and the image side surface of which can be a concave surface or a convex surface. The third lens can have a positive focal power, the object side surface of which can be a concave surface or a convex surface, and the image side surface of which is a convex surface. The fourth lens can have a negative focal power, the object side surface of which is a concave surface, and the image side surface of which is a concave surface. The fifth lens can have a positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a plane or a concave surface.

[0052] In some embodiments, the optical lens can further comprise a diaphragm for limiting the light beam, which can be located between the third lens and the fourth lens or between the object side and the first lens, so as to reduce the generation of ghost images of the optical lens and effectively reduce the difficulty of distortion correction of the lens.

[0053] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 1.35°<FOV / Fno<1.75°. Satisfying the above range, the optical lens has a suitable field of view and aperture value. More specifically, 1.49°<FOV / Fno<1.59°.

[0054] In some embodiments, the back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0.4<BFL / TTL<0.6. Satisfying the above range, the lens has a larger back focus, which is beneficial to the assembly of the module, reduces interference and improves production yield. More specifically, 0.43<BFL / TTL<0.52.

[0055] In some embodiments, the image side surface curvature radius R8 of the fourth lens and the object side surface curvature radius R9 of the fifth lens satisfy: -0.4<(R8-R9) / (R8+R9)≤0. Satisfying the above range, the light deflection angle can be reduced, the light trend is more stable, and the coma and field curvature can be corrected, the imaging flatness is improved, and the imaging quality of the optical lens is improved. More specifically, -0.12<(R8-R9) / (R8+R9)≤0.

[0056] In some embodiments, the effective focal length f of the optical lens satisfies: 80mm < f < 100mm; the chief ray angle of incidence (CRA) at the maximum image height of the optical lens satisfies: 2.7° < CRA < 5.5°. The above ranges are satisfied so that the optical lens has a telephoto characteristic and has a smaller CRA, which can achieve a close-up of a distant scene and highlight the subject. More specifically, 87mm < f < 93mm; 2.9° < CRA < 5.1°.

[0057] In some embodiments, the total track length (TTL) of the optical lens and the effective focal length f of the optical lens satisfy: 1 < TTL / f < 1.35. The above ranges are satisfied to limit the total length of the lens while better achieving the telephoto performance of the system. More specifically, 1.08 < TTL / f < 1.34.

[0058] In some embodiments, the total track length (TTL) of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 7.1 < TTL / IH < 11.1. The above ranges are satisfied to achieve a balance between the volume and the large image of the optical lens. More specifically, 7.96 < TTL / IH < 10.14.

[0059] In some embodiments, the real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter (EPD) of the optical lens satisfy: 0.55 < IH / EPD < 0.7. The above ranges are satisfied to increase the width of the light bundle entering the optical lens, so that the brightness of the optical lens at the image plane is improved to avoid dark corners. More specifically, 0.64 < IH / EPD < 0.67.

[0060] In some embodiments, the total track length (TTL) of the optical lens, the real image height IH corresponding to the maximum field of view of the optical lens, and the maximum field of view FOV of the optical lens satisfy: 3.7 / ° < TTL / IH / FOV < 6 / °. The above ranges are satisfied to balance the relationship between the total length, the image height, and the field of view of the optical lens. More specifically, 4.12 / ° < TTL / IH / FOV < 5.41 / °.

[0061] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -0.3 < f4 / f < -0.1; the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 0 < (R7+R8) / (R7-R8) < 0.8. By satisfying the above ranges, the positive spherical aberration generated by the fourth negative lens and the negative spherical aberration generated in the front positive lens are balanced by reasonably setting the focal length and the surface shape of the fourth lens, the overall imaging quality is improved, and the light ray trend can be reasonably controlled to avoid the problem of too high lens sensitivity caused by too large light ray deflection. More specifically, -0.22 < f4 / f < -0.17; 0.05 < (R7+R8) / (R7-R8) < 0.62.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.2 < f5 / f < 0.5; the effective focal length f of the optical lens and the radius of curvature R9 of the object side surface of the fifth lens satisfy: 0.15 < R9 / f < 0.35. By satisfying the above ranges, the fifth lens is limited to have appropriate positive refractive power and surface shape of the object side surface, which is conducive to converging light rays and helps to reduce the aberration of the optical lens. More specifically, 0.29 < f5 / f < 0.42; 0.21 < R9 / f < 0.29.

[0063] In some embodiments, the combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f45 of the fourth lens and the fifth lens satisfy: -1 < f123 / f45 < -0.6. By satisfying the above ranges, the focal length relationship between the front and rear lens groups is reasonably set, which is conducive to the smooth transition of light rays, reduces the difficulty of correcting aberration of the rear lens, and improves the image quality of the optical imaging lens. More specifically, -0.91 < f123 / f45 < -0.69.

[0064] In some embodiments, the object side surface half aperture diameter d1 of the first lens and the image side surface half aperture diameter d10 of the fifth lens satisfy: 1.15 < d1 / d10 < 1.8. By satisfying the above ranges, the aperture ratio of the front and rear lenses is controlled to limit the light ray trend within a reasonable range, so that the illumination of the imaging surface is uniform. More specifically, 1.3 < d1 / d10 < 1.67.

[0065] In some embodiments, the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: -10.6 < f3 / f4 < -1.5; the image-side curvature radius R6 of the third lens and the image-side curvature radius R8 of the fourth lens satisfy: -4.2 < R6 / R8 < -2.1. Satisfying the above ranges can reduce the light deflection angle, make the light trend more stable, correct coma and field curvature, improve the flatness of imaging, and improve the imaging quality of the optical lens. More specifically, -9.8 < f3 / f4 < -1.64; -3.83 < R6 / R8 < -2.31.

[0066] In some embodiments, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -0.75 < f4 / f5 < -0.4; the image-side curvature radius R8 of the fourth lens and the object-side curvature radius R9 of the fifth lens satisfy: 0.7 < R8 / R9 < 1.1. Satisfying the above ranges can reduce the light deflection angle, make the light trend more stable, correct coma and field curvature, improve the flatness of imaging, and improve the imaging quality of the optical lens. More specifically, -0.65 < f4 / f5 < -0.48; 0.79 < R8 / R9 < 1.01.

[0067] In some embodiments, the focal length f2 of the second lens and the object-side curvature radius R3 of the second lens satisfy: 0.2 < f2 / R3 < 0.6; the focal length f2 of the second lens and the image-side curvature radius R4 of the second lens satisfy: -1.2 < f2 / R4 < -0.8. Satisfying the above ranges is conducive to reducing the deflection degree of incident light and avoiding excessive refraction changes that produce too many aberrations. More specifically, 0.25 < f2 / R3 < 0.52; -1.09 < f2 / R4 < -0.86.

[0068] In some embodiments, the object-side curvature radius R7 of the fourth lens and the image-side curvature radius R8 of the fourth lens satisfy: -4.5 < R7 / R8 < -1; the object-side curvature radius R7 of the fourth lens, the central thickness CT4 of the fourth lens, and the image-side curvature radius R8 of the fourth lens satisfy: -4.8 < (R7-CT4) / R8 < -1.35. Satisfying the above ranges can effectively reduce the optical path difference between the center and the periphery of the lens, which is conducive to correcting the distortion of the optical lens. More specifically, -4.09 < R7 / R8 < -1.11; -4.39 < (R7-CT4) / R8 < -1.51.

[0069] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV, and the real image height IH corresponding to the maximum field of view satisfy: 0.99 < (IH / 2) / (f*tan(FOV / 2)) < 1.02. Satisfying the above ranges can control the optical lens to have smaller distortion and improve the imaging quality of the optical lens.

[0070] In some embodiments, a real image height IH corresponding to a maximum field angle of the optical lens and an effective focal length f of the optical lens satisfy: 0.1 < IH / f < 0.2. Satisfying the above range, the image height and the focal length of the optical lens are controlled within a reasonable range, which helps the optical lens have long-focus characteristics and improves the imaging quality. More specifically, 0.12 < IH / f < 0.15.

[0071] In some embodiments, the effective focal length f of the optical lens and a back focal length BFL of the optical lens satisfy: 0.4 < BFL / f < 0.75. Satisfying the above range, the optical lens is limited to have a suitable back focus, which facilitates reasonable arrangement of positions of the lenses and reduces the difficulty of processing and assembly. More specifically, 0.47 < BFL / f < 0.66.

[0072] In some embodiments, the effective focal length f of the optical lens and a focal length f1 of the first lens satisfy: 0.4 < f1 / f < 0.8. Satisfying the above range, by setting the first lens to have a large positive refractive power, the incident light can be converged to a large extent, and more light can enter the system, which is conducive to improving the light intake of the lens and enabling the lens to also have high-definition imaging in a dark environment. More specifically, 0.46 < f1 / f < 0.66.

[0073] In some embodiments, the effective focal length f of the optical lens and a focal length f2 of the second lens satisfy: -0.5 < f2 / f < 2. Satisfying the above range is conducive to smooth transition of light and improves the imaging resolution. More specifically, -0.47 < f2 / f < 1.79.

[0074] In some embodiments, the effective focal length f of the optical lens and a focal length f3 of the third lens satisfy: 0.2 < f3 / f < 2.3. Satisfying the above range can make the third lens have appropriate positive refractive power, which is conducive to smooth transition of light and improves the imaging quality of the optical lens. More specifically, 0.29 < f3 / f < 2.1.

[0075] In some embodiments, the focal length f1 of the first lens and the focal length f5 of the fifth lens satisfy: 1.15 < f1 / f5 < 1.9; and the central thickness CT1 of the first lens and the central thickness CT5 of the fifth lens satisfy: 0.7 < CT1 / CT5 < 1.1. Satisfying the above range is conducive to reducing the aberration of the optical lens and improving the imaging quality of the optical lens by controlling the focal length and thickness relationship of the front and rear lenses. More specifically, 1.3 < f1 / f5 < 1.73; and 0.79 < CT1 / CT5 < 0.97.

[0076] In some embodiments, the second lens satisfies the following conditions: -4.6 < R3 / R4 < -1.7, and 1.4 < (R3-R4) / (R3+R4) < 4.2, where R3 is the radius of curvature of the object side surface of the second lens, and R4 is the radius of curvature of the image side surface of the second lens. By satisfying the above conditions, the degree of deflection of light entering the second lens can be effectively slowed down by controlling the surface shape of the second lens, thereby facilitating the miniaturization of the lens head.

[0077] In some embodiments, the optical lens satisfies the following conditions: 17.5mm < EPD < 19.5mm, 90mm < TTL < 125mm, 4.5 < Fno < 5.5, 40mm < BFL < 65mm, 7° < FOV < 8°, and 11mm < IH < 13mm, where EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, BFL represents the back focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, and IH represents the image height corresponding to the maximum field of view angle of the optical lens. By satisfying the above conditions, the optical lens provided by the embodiments of the present application has at least the characteristics of long focal length, large image surface, and small CRA. More specifically, 18.2mm < EPD < 18.5mm, 95.5mm < TTL < 121.6mm, 4.8 < Fno < 5.1, 42.1mm < BFL < 59.7mm, 7.4° < FOV < 7.8°, and 11.9mm < IH < 12.1mm.

[0078] The present application is further described in the following embodiments. In each embodiment, the thickness, the radius of curvature, and the material selection of each lens in the optical lens are different, and the specific differences can be found in the parameter table of each embodiment. The following embodiments are merely preferred embodiments of the present application, and the embodiments of the present application are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present application should be considered as equivalent replacement methods and should be included in the protection scope of the present application.

[0079] Embodiment 1

[0080] Please refer to Figure 1 , which is a structural schematic diagram of an optical lens 100 provided in Embodiment 1 of the present application. The optical lens sequentially includes a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, and a fifth lens L5 along the optical axis from the object side to the imaging surface.

[0081] The first lens L1 has positive refractive power, the object side S1 is a convex surface, and the image side S2 is a plane.

[0082] The second lens L2 has negative refractive power, the object side S3 is a concave surface, and the image side S4 is a concave surface.

[0083] The third lens L3 has positive refractive power, the object side S5 is a convex surface, and the image side S6 is a convex surface.

[0084] The fourth lens L4 has negative refractive power, the object side S7 is a concave surface, and the image side S8 is a concave surface.

[0085] The fifth lens L5 has positive refractive power, the object side S9 is a convex surface, and the image side S10 is a plane.

[0086] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are glass spherical lenses.

[0087] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0088] Table 1-1

[0089]

[0090] In this embodiment, the F-Tan(Theta) distortion curve, the axial aberration curve, the transverse chromatic aberration curve, the MTF curve, and the relative illumination curve of the optical lens 100 are shown in FIGS. Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6

[0091] Figure 2 The F-Tan(Theta) distortion curve of the optical lens 100 in this embodiment is shown, which represents the distortion of different field angles on the imaging surface. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the distortion value is controlled within ±0.08%, which shows that the optical lens 100 can better correct the distortion.

[0092] Figure 3 The axial aberration curve of the optical lens 100 in this embodiment is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within ±0.06mm, which shows that the optical lens 100 can better correct the axial aberration.

[0093] Figure 4 ​The axial chromatic aberration curve of the optical lens 100 in the embodiment is shown, which represents the chromatic aberration of each wavelength at different image heights on the imaging surface relative to the central wavelength (0.59 μm), the horizontal axis represents the axial chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. As can be seen from the figure, the axial chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±0.6 μm, which indicates that the optical lens 100 can correct chromatic aberration very well.

[0094] Figure 5 The modulation transfer function (MTF) curve of the optical lens 100 in the embodiment is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the embodiment is greater than 0.5 in the full field of view, and in the range of 0-100 lp / mm, the MTF curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in the case of low frequency and high frequency.

[0095] Figure 6 The relative luminance curve of the optical lens 100 in the embodiment is shown, which represents the relative luminance value of different field angles on the imaging surface, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative luminance. As can be seen from the figure, the relative luminance value of the optical lens 100 at the edge of the field of view is still greater than 98%, which indicates that the optical lens 100 has very good relative luminance.

[0096] Embodiment 2

[0097] Please refer to Figure 7 , which is a structural schematic diagram of the optical lens 200 provided in the embodiment 2 of the present application. Compared with the embodiment 1, the main difference is that the second lens L2 has a positive focal power; the object side S3 of the second lens L2 is a convex surface; the image side S4 of the second lens L2 is a convex surface; the object side S5 of the third lens L3 is a concave surface; the image side S10 of the fifth lens L5 is a concave surface; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0098] The related parameters of each lens in the optical lens 200 in the embodiment 2 are shown in Table 2-1.

[0099] Table 2-1

[0100]

[0101] In the embodiment, the F-Tan (Theta) distortion curve, the axial aberration curve, the axial chromatic aberration curve, the MTF curve, and the relative luminance curve of the optical lens 200 are respectively as shown in Figure 8 , Figure 9 ,Figure 10 、 Figure 11 、 Figure 12 .

[0102] It can be seen from Figure 8 that the distortion value is controlled within ±0.03%, which indicates that the optical lens 200 can correct the distortion well.

[0103] It can be seen from Figure 9 that the shift amount of the axial aberration is controlled within ±0.06mm, which indicates that the optical lens 200 can correct the axial aberration well.

[0104] It can be seen from Figure 10 that the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±0.4μm, which indicates that the optical lens 200 can correct the chromatic aberration very well.

[0105] It can be seen from Figure 11 that the MTF value of the embodiment is above 0.5 in the full field of view, and in the range of 0-100lp / mm, the MTF curve is uniformly and smoothly decreased from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in the case of low frequency and high frequency.

[0106] It can be seen from Figure 12 that the relative luminance value of the optical lens 200 at the edge of the field of view is still greater than 98%, which indicates that the optical lens 200 has very good relative luminance.

[0107] Embodiment 3

[0108] Please refer to Figure 13 , which is a structural schematic diagram of the optical lens 300 provided in the embodiment 3 of the present application, and the main difference between the embodiment and the embodiment 1 is that the optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.

[0109] The related parameters of each lens in the optical lens 300 in the embodiment 3 are shown in Table 3-1.

[0110] Table 3-1

[0111]

[0112] In the embodiment, the F-Tan(Theta) distortion curve, the axial aberration curve, the transverse chromatic aberration curve, the MTF curve and the relative luminance curve of the optical lens 300 are respectively shown in Figure 14 、 Figure 15 、 Figure 16 、 Figure 17 、 Figure 18 .

[0113] It can be seen fromFigure 14 As can be seen from Table 6, the distortion value is controlled within ±0.15%, which indicates that the optical lens 300 can better correct the distortion.

[0114] From Table 7, it can be seen that the shift of the axial aberration is controlled within ±0.05mm, which indicates that the optical lens 300 can better correct the axial aberration. Figure 15 From Table 8, it can be seen that the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±0.2μm, which indicates that the optical lens 300 can very well correct the chromatic aberration.

[0115] Figure 16 From Table 9, it can be seen that the MTF value of the embodiment is above 0.5 in the full field of view, and in the range of 0-100lp / mm, the MTF curve is uniformly and smoothly decreased from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in the case of low frequency and high frequency.

[0116] From Table 10, it can be seen that the relative luminance value of the optical lens 300 is still greater than 90% at the edge of the field of view, which indicates that the optical lens 300 has very good relative luminance. Figure 17 Table 4

[0117] Figure 18

[0118] Table 4

[0119] Table 4

[0120]

[0121]

[0122] In summary of the above embodiments, the optical lens provided by the present application has at least the following advantages:

[0123] (1) The object side of the first lens is convex, which helps to converge the incident light and reduce the head lens aperture, and is beneficial to the miniaturization of the head. The lens has long-focus characteristics, can better present larger local details, and make the picture more concentrated and compact; and can also realize the large image surface characteristics of the lens, and realize high-definition imaging of the lens.

[0124] ​​​(2) By specific surface shape setting and reasonable power distribution, the lens has the characteristics of high relative luminance, can well collect real images, and the collected image picture brightness is uniform. The imaging quality of the optical lens can be improved, the distortion is small, the aberration is reduced, and the imaging quality of the optical lens is improved.

[0125] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0126] The above-described embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but cannot be understood as the limitation of the patent scope of the present application. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An optical lens, in total five pieces of lenses, characterized in that, In order from the object side to the imaging surface along the optical axis, comprises successively: a first lens with positive refractive power, the object side surface of which is convex, and the image side surface of which is flat; a second lens with refractive power; a third lens with positive refractive power, the image side surface of which is convex; a fourth lens with negative refractive power, the object side surface of which is concave, and the image side surface of which is concave; a fifth lens with positive refractive power, the object side surface of which is convex, and the image side surface of which is flat or concave; wherein the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 1.35°<FOV / Fno<1.75°; the back focal length BFL of the optical lens and the total track length TTL of the optical lens satisfy: 0.4<BFL / TTL<0.6; the image side surface curvature radius R8 of the fourth lens and the object side surface curvature radius R9 of the fifth lens satisfy: -0.4<(R8-R9) / (R8+R9)≤0.

2. The optical lens of claim 1, wherein, The effective focal length f of the optical lens satisfies: 80mm<f<100mm; the chief ray angle of incidence CRA at the maximum image height of the optical lens satisfies: 2.7°<CRA<5.5°.

3. The optical lens of claim 1, wherein, The total track length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1<TTL / f<1.35; the total track length TTL of the optical lens and the real image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 7.1<TTL / IH<11.

1.

4. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 0.55<IH / EPD<0.7; the total track length TTL of the optical lens, the real image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 3.7 / °<TTL / IH / FOV<6 / °.

5. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -0.3<f4 / f<-0.1; the object side surface curvature radius R7 of the fourth lens and the image side surface curvature radius R8 of the fourth lens satisfy: 0<(R7+R8) / (R7-R8)<0.

8.

6. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.2<f5 / f<0.5; the effective focal length f of the optical lens and the object side surface curvature radius R9 of the fifth lens satisfy: 0.15<R9 / f<0.

35.

7. The optical lens of claim 1, wherein, The combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f45 of the fourth lens and the fifth lens satisfy: -1<f123 / f45<-0.6; the object side surface half light entrance radius d1 of the first lens and the image side surface half light entrance radius d10 of the fifth lens satisfy: 1.15<d1 / d10<1.

8.

8. The optical lens of claim 1, wherein, The focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy -10.6 < f3 / f4 < -1.5; the image-side surface curvature radius R6 of the third lens and the image-side surface curvature radius R8 of the fourth lens satisfy -4.2 < R6 / R8 < -2.

1.

9. The optical lens of claim 1, wherein, The focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy -0.75 < f4 / f5 < -0.4; the image-side surface curvature radius R8 of the fourth lens and the object-side surface curvature radius R9 of the fifth lens satisfy 0.7 < R8 / R9 < 1.

1.

10. The optical lens of claim 1, wherein, The focal length f2 of the second lens and the object-side surface curvature radius R3 of the second lens satisfy 0.2 < f2 / R3 < 0.6; the focal length f2 of the second lens and the image-side surface curvature radius R4 of the second lens satisfy -1.2 < f2 / R4 < -0.

8.

11. The optical lens of claim 1, wherein, The object-side surface curvature radius R7 of the fourth lens and the image-side surface curvature radius R8 of the fourth lens satisfy -4.5 < R7 / R8 < -1; the object-side surface curvature radius R7 of the fourth lens, the central thickness CT4 of the fourth lens and the image-side surface curvature radius R8 of the fourth lens satisfy -4.8 < (R7-CT4) / R8 < -1.35.

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