Optical lens

Abstract

The invention provides an optical lens, which comprises eight lenses with focal power and sequentially comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with negative focal power from an object side to an imaging surface along an optical axis, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the third lens has negative focal power, the object side surface of the third lens near the optical axis is a convex surface, and the image side surface of the third lens is a concave surface; the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface; the sixth lens has positive focal power; the seventh lens has negative focal power; and the eighth lens has positive focal power. The optical lens provided by the invention has one or more advantages of short focus, large field angle, high imaging quality and the like.

Description

TECHNICAL FIELD

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

[0002] The fisheye lens has the shooting characteristic of super wide angle, and the actual shooting picture can accommodate more and wider scenes, which can meet the shooting of some large scene range, and is widely used in the fields of sports cameras, unmanned aerial vehicles, panoramic monitoring and the like. However, the existing fisheye lens device still has many deficiencies, for example, the increase of the field angle of view of the lens leads to the difficulty in system aberration correction and the decline of the imaging quality; the lens size is long and the volume is large, etc. Therefore, it is necessary to develop an optical lens with one or more advantages of large field angle of view, high imaging quality, small volume and the like, so as to better meet the market demand. SUMMARY

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

[0004] The technical scheme adopted by the present application is as follows: An optical lens, which comprises eight lenses with optical power, and sequentially comprises, along the optical axis from the object side to the imaging surface: a first lens with negative optical power, whose object side surface is a convex surface and whose image side surface is a concave surface; a second lens with negative optical power, whose object side surface is a convex surface and whose image side surface is a concave surface; a third lens with negative optical power, whose object side surface is a convex surface at the near optical axis and whose image side surface is a concave surface; a fourth lens with positive optical power, whose object side surface is a convex surface and whose image side surface is a convex surface; a fifth lens with positive optical power, whose object side surface is a convex surface and whose image side surface is a convex surface; a sixth lens with positive optical power; a seventh lens with negative optical power; an eighth lens with positive optical power; wherein the object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: 0.1<(R5-R6) / (R5+R6)<0.9; and the object side surface curvature radius R7 of the fourth lens and the image side surface curvature radius R8 of the fourth lens satisfy: |(R7+R8) / (R7-R8)|<0.6.

[0005] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 18<TTL / f<23; and the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of view of the optical lens satisfy: 5.5<TTL / IH<10.

[0006] Further preferably, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 90° < FOV / Fno < 120°; 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: 4.6 < IH / EPD < 7.8.

[0007] Further preferably, the real image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 2.1 < IH / f < 3.5; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.6 < BFL / f < 3.5.

[0008] Further preferably, 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: 17 < 180° x TTL / (IH / 2) / (FOV / 2) < 30; the half entrance pupil diameter d1 of the object side of the first 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: -7 < d1 / (IH / 2) / Tan(FOV / 2) < -2.1.

[0009] Further preferably, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -8 < f2 / f < -3; the object side surface curvature radius R3 of the second lens and the effective focal length f of the optical lens satisfy: 10 < R3 / f < 69; the image side surface curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: 2.2 < R4 / f < 5.1.

[0010] Further preferably, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -50 < f3 / f < -7; the object side surface curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: 3.8 < R5 / f < 68; the image side surface curvature radius R6 of the third lens and the effective focal length f of the optical lens satisfy: 2.3 < R6 / f < 5.

[0011] Further preferably, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 5.1 < f4 / f < 7.3; the object side surface curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: 4.5 < R7 / f < 13; the image side surface curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -20 < R8 / f < -7.

[0012] It is further preferred that the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 3.1 < f5 / f < 5.9; the object side surface curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: 3.5 < R9 / f < 7; and the image side surface curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -9 < R10 / f < -2.9.

[0013] It is further preferred that the object side surface curvature radius R3 of the second lens and the image side surface curvature radius R4 of the second lens satisfy: 0.6 < (R3-R4) / (R3+R4) < 1; and the object side surface curvature radius R9 of the fifth lens and the image side surface curvature radius R10 of the fifth lens satisfy: |(R9+R10) / (R9-R10)| < 0.4.

[0014] The optical lens provided by the application adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved, so that the lens has one or more advantages such as short focal length, large field of view, high imaging quality, and the like. BRIEF DESCRIPTION OF DRAWINGS

[0015] The above and / or additional aspects and advantages of the application will become apparent and be readily understood from the following description, taken in connection with the accompanying drawings, in which: Figure 1 FIG. 1 is a structural schematic diagram of an optical lens according to an embodiment of the application.

[0016] Figure 2 FIG. 2 is an MTF curve diagram of the optical lens in FIG. 1.

[0017] Figure 3 FIG. 3 is a structural schematic diagram of an optical lens according to another embodiment of the application.

[0018] Figure 4 FIG. 4 is an MTF curve diagram of the optical lens in FIG. 3.

[0019] Figure 5 FIG. 5 is a structural schematic diagram of an optical lens according to another embodiment of the application.

[0020] Figure 6 FIG. 6 is an MTF curve diagram of the optical lens in FIG. 5.

[0021] Figure 7 FIG. 7 is a structural schematic diagram of an optical lens according to another embodiment of the application.

[0022] Figure 8 FIG. 8 is an MTF curve diagram of the optical lens in FIG. 7.

[0023] Figure 9 FIG. 5 is a structure diagram of an optical lens according to an embodiment of the present application.

[0024] Figure 10 FIG. 6 is an MTF curve diagram of the optical lens according to the embodiment of the present application.

[0025] Figure 11 FIG. 7 is a structure diagram of an optical lens according to an embodiment of the present application.

[0026] Figure 12 FIG. 8 is an MTF curve diagram of the optical lens according to the embodiment of the present application.

[0027] Figure 13 FIG. 9 is a structure diagram of an optical lens according to an embodiment of the present application.

[0028] Figure 14 FIG. 10 is an MTF curve diagram of the optical lens according to the embodiment of the present application.

[0029] Figure 15 FIG. 11 is a structure diagram of an optical lens according to an embodiment of the present application.

[0030] Figure 16 FIG. 12 is an MTF curve diagram of the optical lens according to the embodiment of the present application.

[0031] The following detailed description will further describe the present application with reference to the above drawings. DETAILED DESCRIPTION

[0032] For a better understanding of the present application, various aspects of the present application will be described in relation to the drawings. It is to be understood that these detailed descriptions are only descriptions of 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.

[0033] It is to be noted that, in the present specification, the expressions first, second, third and the like 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 the second lens or the third lens without departing from the teachings of the present application.

[0034] In the drawings, the thickness, size, and shape of lenses have been slightly exaggerated for the sake of convenience in explanation. Specifically, the shape of a spherical surface or an aspherical surface shown in the drawings is shown by way of example. That is, the shape of a spherical surface or an aspherical surface is not limited to the shape of a spherical surface or an aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0035] In the present disclosure, 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 imaging plane is referred to as the image side surface of the lens.

[0036] 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. In addition, when expressions such as "at least one of" appear after a list of two or more items, the phrase is intended to refer to any combination of one or more of the listed items, but not a single combination of one of the items. In addition, when describing embodiments of the present application, the word "may" means "one or more embodiments of the present application". Also, the word "exemplary" is intended to mean an example or an illustration.

[0037] 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 also be understood that the terms 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.

[0038] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0039] The optical lens provided by the embodiments of the present application comprises eight lenses with optical power, which are sequentially arranged along the optical axis from the object side to the imaging plane as the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens.

[0040] In some embodiments, the first lens can have a negative focal power, the object side surface can be convex, and the image side surface can be concave. The second lens can have a negative focal power, the object side surface can be convex, and the image side surface can be concave. The third lens can have a negative focal power, the object side surface can be convex at the near optical axis, and the image side surface can be concave. The fourth lens can have a positive focal power, the object side surface can be convex, and the image side surface can be convex. The fifth lens can have a positive focal power, the object side surface can be convex, and the image side surface can be convex. The sixth lens can have a positive focal power, the object side surface can be convex or concave, and the image side surface can be convex or concave. The seventh lens can have a negative focal power, the object side surface can be concave or convex, and the image side surface can be concave or convex. The eighth lens can have a positive focal power, the object side surface can be convex or concave, and the image side surface can be convex or concave.

[0041] In some embodiments, the optical lens can further include a diaphragm, which can be located between the fourth lens and the fifth lens. It can be understood that the diaphragm is used to limit the amount of light to change the brightness of the imaging.

[0042] In some embodiments, the optical lens can further include a filter, which is located between the eighth lens and the imaging surface along the optical axis. The filter is used to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0043] In some embodiments, the sixth lens and the seventh lens can be cemented to form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the sensitivity of the optical lens to decentration, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; and can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0044] In some embodiments, the object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: 0.1 < (R5-R6) / (R5+R6) < 0.9; and the object side surface curvature radius R7 of the fourth lens and the image side surface curvature radius R8 of the fourth lens satisfy: |(R7+R8) / (R7-R8)| < 0.6. Satisfying the above range is conducive to adjusting the light path, so that the optical lens has a large field of view. More specifically: 0.14 < (R5-R6) / (R5+R6) < 0.9; and -0.59 < (R7+R8) / (R7-R8) < 0.17.

[0045] In some embodiments, the optical total track length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 18 < TTL / f < 23; the optical 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: 5.5 < TTL / IH < 10. Satisfying the above range can effectively limit the length of the lens, which is conducive to the miniaturization of the optical lens. More specifically: 18.96 < TTL / f < 21.72; 6.14 < TTL / IH < 9.32.

[0046] In some embodiments, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 90° < FOV / Fno < 120°; 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: 4.6 < IH / EPD < 7.8. Satisfying the above range can reasonably limit the ratio of the field of view angle and the aperture value, which is conducive to improving the light amount of the lens and enabling the lens to also have high-definition imaging in a dim environment. At the same time, reasonably limiting the ratio of the image height and the entrance pupil diameter is conducive to increasing the light amount, so that the brightness of the peripheral field of view and the central field of view is more uniform. More specifically: 99° < FOV / Fno < 110°; 5.1 < IH / EPD < 7.11.

[0047] In some embodiments, the real image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.1 < IH / f < 3.5; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.6 < BFL / f < 3.5. Satisfying the above range can achieve a larger field of view angle and ensure a large depth of field. At the same time, limiting the optical lens to have a suitable back focus facilitates reasonable arrangement of the positions of the lenses and reduces the difficulty of processing and assembly. More specifically: 2.31 < IH / f < 3.24; 1.7 < BFL / f < 3.17.

[0048] In some embodiments, the optical 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: 17 < 180° × TTL / (IH / 2) / (FOV / 2) < 30; the light passing half-aperture diameter d1 of the first lens on the object side, 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: -7 < d1 / (IH / 2) / Tan(FOV / 2) < -2.1. Satisfying the above range is conducive to balancing the relationship among the total length, the image height, and the field of view angle of the optical lens. At the same time, it can reasonably arrange the overall geometry of the optical lens and improve its structural stability. More specifically: 18.43 < 180° × TTL / (IH / 2) / (FOV / 2) < 27.97; -6.79 < d1 / (IH / 2) / Tan(FOV / 2) < -2.36.

[0049] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -8 < f2 / f < -3; the radius of curvature R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: 10 < R3 / f < 69; and the radius of curvature R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: 2.2 < R4 / f < 5.1. Satisfying the above ranges, the proportion of the refractive power of the second lens and the surface shape thereof are reasonably limited, which can further diverge the light rays and improve the field angle of the imaging system. More specifically, -7.61 < f2 / f < -3.35; 10.42 < R3 / f < 62.46; and 2.41 < R4 / f < 4.71.

[0050] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -50 < f3 / f < -7; the radius of curvature R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy: 3.8 < R5 / f < 68; and the radius of curvature R6 of the image side surface of the third lens and the effective focal length f of the optical lens satisfy: 2.3 < R6 / f < 5. Satisfying the above ranges, the proportion of the refractive power of the third lens and the surface shape thereof are reasonably limited, which is conducive to adjusting the light ray trend from the first lens and the second lens, making the edge light rays continue to diverge after passing through the third lens, and correcting the edge field aberration. More specifically, -47.09 < f3 / f < -7.36; 4.16 < R5 / f < 62.36; and 2.56 < R6 / f < 4.61.

[0051] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 5.1 < f4 / f < 7.3; the radius of curvature R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 4.5 < R7 / f < 13; and the radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -20 < R8 / f < -7. Satisfying the above ranges, the proportion of the refractive power of the fourth lens and the surface shape thereof are reasonably limited, which can converge the light rays and correct the aberration problem caused by the first three negative focal length lenses. More specifically, 5.62 < f4 / f < 6.73; 4.93 < R7 / f < 12.1; and -18.83 < R8 / f < -7.77.

[0052] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 3.1 < f5 / f < 5.9; the object-side surface curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: 3.5 < R9 / f < 7; and the image-side surface curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -9 < R10 / f < -2.9. Satisfying the above ranges, the proportion of the refractive power of the fifth lens and the surface shape thereof are reasonably limited, and the light distribution is further limited in cooperation with the fourth lens to balance aberrations. More specifically, 3.47 < f5 / f < 5.4; 3.79 < R9 / f < 6.61; and -8.38 < R10 / f < -3.17.

[0053] In some embodiments, the object-side surface curvature radius R3 of the second lens and the image-side surface curvature radius R4 of the second lens satisfy: 0.6 < (R3-R4) / (R3+R4) < 1; and the object-side surface curvature radius R9 of the fifth lens and the image-side surface curvature radius R10 of the fifth lens satisfy: |(R9+R10) / (R9-R10)| < 0.4. Satisfying the above ranges, the aberrations of the optical lens can be corrected, and the tolerance sensitivity of the optical lens is reduced. More specifically, 0.6 < (R3-R4) / (R3+R4) < 0.93; and -0.39 < (R9+R10) / (R9-R10) < 0.3.

[0054] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -19 < f1 / f < -6.2. Satisfying the above ranges, the proportion of the refractive power of the first lens is reasonably limited, and the light at a large field of view can be collected to a greater extent, so that the light enters the rear optical system, the light flux is increased, and the field of view is improved. More specifically, -17.26 < f1 / f < -6.84.

[0055] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.6 < f6 / f < 10. Satisfying the above ranges, the proportion of the refractive power of the sixth lens is reasonably limited, and the aberrations at the edge of the field of view can be effectively improved, and the overall imaging quality of the optical lens is improved. More specifically, 1.78 < f6 / f < 9.1.

[0056] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -5.5 < f7 / f < -1.5. Satisfying the above ranges, the proportion of the refractive power of the seventh lens is reasonably limited, and the aberrations generated at the front end of the lens can be effectively corrected, and the imaging quality of the lens is improved. More specifically, -5.07 < f7 / f < -1.63.

[0057] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 4 < f8 / f < 70. Satisfying the above range, the ratio of the power of the eighth lens is reasonably limited, which is conducive to reducing the sensitivity of the optical lens to decentration and improving the imaging resolution. More specifically: 4.33 < f8 / f < 64.87.

[0058] In some embodiments, the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 2.7 < f5678 / f < 3.9. Satisfying the above range, the ratio of the power of the stop rear lens group is limited, which is conducive to correcting the chromatic aberration and field curvature of the optical system, reducing the sensitivity, and reducing the difficulty of lens forming. More specifically: 2.98 < f5678 / f < 3.58.

[0059] In some embodiments, the optical lens satisfies the following conditional expressions: 0.75mm < f < 0.85mm; 210° < FOV < 250°; 0.3mm < EPD < 0.4mm; 15mm < TTL < 18mm; 2.1 < Fno < 2.3; 1.8mm < IH < 2.8mm; 16° < CRA < 30°; 1.3mm < BFL < 2.7mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, 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, IH represents the real image height corresponding to the maximum field of view angle of the optical lens, CRA represents the chief ray incidence angle at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. Satisfying the above range, the optical lens has one or more advantages such as short focal length, large field of view angle, high imaging quality, etc. More specifically: 0.79mm < f < 0.82mm; 219° < FOV < 241°; 0.35mm < EPD < 0.38mm; 15.28mm < TTL < 17.39mm; 2.19 < Fno < 2.21; 1.86mm < IH < 2.59mm; 16.34° < CRA < 29.1°; 1.36mm < BFL < 2.54mm.

[0060] In some embodiments, the lens material in the optical lens provided by the present application can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. When the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristics of the glass itself. The first lens, the second lens, the fourth lens, the sixth lens, the seventh lens and the eighth lens in the optical lens provided by the present application can adopt glass material, and the third lens and the fifth lens can adopt plastic material. The adoption of the glass-plastic hybrid structure can effectively reduce the cost, correct the aberration, reduce the size, improve the thermal stability and provide an optical lens product with higher performance-price ratio.

[0061] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens can adopt a spherical lens or an aspherical lens. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses and better realizing the miniaturization of the lens. More specifically, the first lens, the second lens, the fourth lens, the sixth lens, the seventh lens and the eighth lens in the present application adopt a spherical lens, and the third lens and the fifth lens adopt an aspherical lens.

[0062] In various embodiments of the present application, when the lens adopts an aspherical lens, the shape of each aspherical surface of the optical lens satisfies the following equation: ; wherein z is the distance of the curved surface from the vertex of the curved surface in the direction of the optical axis, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the quadratic surface coefficient, and B, C, D, E, F, G and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order and sixteenth-order surface coefficients, respectively.

[0063] The present application will be further described in the following embodiments. In various embodiments, 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 referred to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present application, but the embodiments of the present application are not limited to the following embodiments only, and any changes, substitutions, combinations or simplifications made without departing from the innovative points of the present application should be regarded as equivalent replacement modes, and all are included in the protection scope of the present application.

[0064] Embodiment 1 Please refer to Figure 1Figure 1 shows a structural schematic diagram of an optical lens 100 provided in Embodiment 1 of the present application, which comprises, along the optical axis from the object side to the imaging surface, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a stop ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0065] The first lens L1 has negative focal power, the object side S1 is a convex surface, and the image side S2 is a concave surface. The second lens L2 has negative focal power, the object side S3 is a convex surface, and the image side S4 is a concave surface. The third lens L3 has negative focal power, the object side S5 is a convex surface at the near optical axis, and the image side S6 is a concave surface. The fourth lens L4 has positive focal power, the object side S7 is a convex surface, and the image side S8 is a convex surface. The fifth lens L5 has positive focal power, the object side S9 is a convex surface, and the image side S10 is a convex surface. The sixth lens L6 has positive focal power, the object side S11 is a convex surface, and the image side is a convex surface. The seventh lens L7 has negative focal power, the object side is a concave surface, and the image side S13 is a concave surface. The sixth lens L6 and the seventh lens L7 form a cemented lens group, i.e., the cemented surface S12 of the image side of the sixth lens L6 and the object side of the seventh lens L7. The eighth lens L8 has positive focal power, the object side S14 is a convex surface, and the image side S15 is a convex surface. The object side S16 and the image side S17 of the filter G1 are both flat surfaces. The imaging surface S18 is a flat surface.

[0066] The first lens L1, the second lens L2, the fourth lens L4, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are all glass spherical lenses, and the third lens L3 and the fifth lens L5 are plastic aspherical lenses.

[0067] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0068] Table 1-1 The aspherical lens surface parameters of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0069] Table 1-2 In this embodiment, the MTF curve of the optical lens 100 is shown in Figure 1. Figure 2 ​

[0070] Figure 2 The MTF (Modulation Transfer Function) curve of the embodiment 1 is shown, which represents the lens imaging modulation degree of 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. It can be seen from the figure that the MTF value of the embodiment is above 0.4 in the full field of view, and in the range of 0-160 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 ability in the case of low frequency and high frequency.

[0071] Embodiment 2 Please refer to Figure 3 , 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 of the embodiment is that the image side S13 of the seventh lens L7 is a convex surface; the image side S15 of the eighth lens L8 is a concave surface; the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0072] The related parameters of each lens in the optical lens 200 in the embodiment 2 are shown in Table 2-1.

[0073] Table 2-1 The surface type parameters of the aspheric lens of the optical lens 200 in the embodiment 2 are shown in Table 2-2.

[0074] Table 2-2 In the embodiment, the MTF curve of the optical lens 200 is shown in Figure 4 . It can be seen from Figure 4 that the MTF value of the embodiment is above 0.5 in the full field of view, and in the range of 0-160 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 ability in the case of low frequency and high frequency.

[0075] Embodiment 3 Please refer to Figure 5 , which is a structural schematic diagram of the optical lens 300 provided in the embodiment 3 of the present application. Compared with the embodiment 1, the main difference of the embodiment is that the image side S15 of the eighth lens L8 is a concave surface; the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0076] The related parameters of each lens in the optical lens 300 in the embodiment 3 are shown in Table 3-1.

[0077] Table 3-1 The surface profile parameters of the aspherical lenses of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0078] Table 3-2 In this embodiment, the MTF curve of the optical lens 300 is shown in Figure 6 It can be seen from Figure 6 that the MTF value of this embodiment is above 0.5 in the full field of view, and in the range of 0-160 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 ability in both low and high frequency cases.

[0079] Embodiment 4 Please refer to Figure 7 , which is a structural schematic diagram of the optical lens 400 provided in Embodiment 4 of the present application. Compared with Embodiment 1, the main difference is that the object side S11 of the sixth lens L6 is a concave surface; the image side S15 of the eighth lens L8 is a concave surface; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0080] The related parameters of each lens in the optical lens 400 in Embodiment 4 are shown in Table 4-1.

[0081] Table 4-1 The surface profile parameters of the aspherical lenses of the optical lens 400 in Embodiment 4 are shown in Table 4-2.

[0082] Table 4-2 In this embodiment, the MTF curve of the optical lens 400 is shown in Figure 8 It can be seen from Figure 8 that the MTF value of this embodiment is above 0.4 in the full field of view, and in the range of 0-160 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 ability in both low and high frequency cases.

[0083] Embodiment 5 Please refer to Figure 9 , which is a structural schematic diagram of the optical lens 500 provided in Embodiment 5 of the present application. Compared with Embodiment 1, the main difference is that the object side S14 of the eighth lens L8 is a concave surface; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0084] The related parameters of each lens in the optical lens 500 in Embodiment 5 are shown in Table 5-1.

[0085] Table 5-1 The surface profile parameters of the aspheric lens of the optical lens 500 in Embodiment 5 are shown in Table 5-2.

[0086] Table 5-2 In this embodiment, the MTF curve of the optical lens 500 is shown in Figure 10 From Figure 10 it can be seen that the MTF value of this embodiment is above 0.5 in the full field of view, and in the range of 0-160 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 ability in the case of low frequency and high frequency.

[0087] Embodiment 6 Please refer to Figure 11 , which is a structural schematic diagram of the optical lens 600 provided in Embodiment 6 of the present application. Compared with Embodiment 1, the main difference is that the image side surface S12 of the sixth lens L6 is a concave surface; the object side surface S12 of the seventh lens L7 is a convex surface; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0088] The related parameters of each lens in the optical lens 600 in Embodiment 6 are shown in Table 6-1.

[0089] Table 6-1 The surface profile parameters of the aspheric lens of the optical lens 600 in Embodiment 6 are shown in Table 6-2.

[0090] Table 6-2 In this embodiment, the MTF curve of the optical lens 600 is shown in Figure 12 From Figure 12 it can be seen that the MTF value of this embodiment is above 0.5 in the full field of view, and in the range of 0-160 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 ability in the case of low frequency and high frequency.

[0091] Embodiment 7 Please refer to Figure 13The figure shown is a schematic diagram of the structure of the optical lens 700 provided in Embodiment 7 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S11 of the sixth lens L6 is concave; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0092] The relevant parameters of each lens in the optical lens 700 in Example 7 are shown in Table 7-1.

[0093] Table 7-1 The surface profile parameters of the aspherical lens of the optical lens 700 in Example 7 are shown in Table 7-2.

[0094] Table 7-2 In this embodiment, the MTF curve of the optical lens 700 is as follows: Figure 14 As shown. From Figure 14 As can be seen, the MTF value of this embodiment is above 0.5 throughout the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0095] Example 8 Please see Figure 15 The figure shown is a schematic diagram of the structure of the optical lens 800 provided in Embodiment 8 of the present invention. The main difference between this embodiment and Embodiment 1 is that the image side surface S13 of the seventh lens L7 is a convex surface; the object side surface S14 of the eighth lens L8 is a concave surface; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0096] The relevant parameters of each lens in the optical lens 800 in Example 8 are shown in Table 8-1.

[0097] Table 8-1 The surface profile parameters of the aspherical lens of the optical lens 800 in Example 8 are shown in Table 8-2.

[0098] Table 8-2 In this embodiment, the MTF curve of the optical lens 800 is as follows: Figure 16 As shown. From Figure 16It 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 0-160 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 ability in the case of low frequency and high frequency.

[0099] Please refer to Table 9-1 and Table 9-2, the optical characteristics corresponding to each of the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the chief ray angle of incidence CRA at the maximum image height, the real image height IH corresponding to the maximum field of view angle, the maximum field of view angle FOV, the entrance pupil diameter EPD, the back focal length BFL, and the numerical value corresponding to each conditional expression in each embodiment.

[0100] Table 9-1 Table 9-2 In summary of the above embodiments, the optical lens provided by the present application adopts eight lenses with specific optical power, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved, so that the lens has one or more advantages such as short focal length, large field of view angle, and high imaging quality.

[0101] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction 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 refer to 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.

[0102] The above-described embodiments only express several embodiments of the present application, which are described in a more specific and detailed manner, but should not be understood as limiting the scope of the patent of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection 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, eight pieces of lenses with optical power, characterized in that, In order from the object side to the imaging plane along the optical axis, the optical lens comprises in sequence: a first lens with negative refractive power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; a second lens with negative refractive power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; a third lens with negative refractive power, the object side surface of which is a convex surface at the near optical axis, and the image side surface of which is a concave surface; a fourth lens with positive refractive power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; a fifth lens with positive refractive power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; a sixth lens with positive refractive power; a seventh lens with negative refractive power; an eighth lens with positive refractive power; wherein the object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: 0.1<(R5-R6) / (R5+R6)<0.9; the object side surface curvature radius R7 of the fourth lens and the image side surface curvature radius R8 of the fourth lens satisfy: |(R7+R8) / (R7-R8)|<0.

6.

2. The optical lens of claim 1, wherein, The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 18<TTL / f<23; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 5.5<TTL / IH<10.

3. The optical lens of claim 1, wherein, The maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 90°<FOV / Fno<120°; the real image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4.6<IH / EPD<7.

8.

4. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.1<IH / f<3.5; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.6<BFL / f<3.

5.

5. The optical lens of claim 1, wherein, The total optical length TTL of the optical lens, the real image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 17<180°×TTL / (IH / 2) / (FOV / 2)<30; the first lens object side surface half light entrance radius d1, the real image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: -7<d1 / (IH / 2) / Tan(FOV / 2)<-2.

1.

6. The optical lens of claim 1, wherein, The focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -8<f2 / f<-3; the object side surface curvature radius R3 of the second lens and the effective focal length f of the optical lens satisfy: 10<R3 / f<69; the image side surface curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: 2.2<R4 / f<5.

1.

7. The optical lens of claim 1, wherein, A focal length f3 of the third lens and an effective focal length f of the optical lens satisfy: -50 < f3 / f < -7; a radius of curvature R5 of an object side surface of the third lens and the effective focal length f of the optical lens satisfy: 3.8 < R5 / f < 68; and a radius of curvature R6 of an image side surface of the third lens and the effective focal length f of the optical lens satisfy: 2.3 < R6 / f < 5.

8. The optical lens of claim 1, wherein, A focal length f4 of the fourth lens and an effective focal length f of the optical lens satisfy: 5.1 < f4 / f < 7.3; a radius of curvature R7 of an object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 4.5 < R7 / f < 13; and a radius of curvature R8 of an image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -20 < R8 / f < -7.

9. The optical lens of claim 1, wherein, A focal length f5 of the fifth lens and an effective focal length f of the optical lens satisfy: 3.1 < f5 / f < 5.9; a radius of curvature R9 of an object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 3.5 < R9 / f < 7; and a radius of curvature R10 of an image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -9 < R10 / f < -2.

9.

10. The optical lens of claim 1, wherein, A radius of curvature R3 of an object side surface of the second lens and a radius of curvature R4 of an image side surface of the second lens satisfy: 0.6 < (R3-R4) / (R3+R4) < 1; and a radius of curvature R9 of an object side surface of the fifth lens and a radius of curvature R10 of an image side surface of the fifth lens satisfy: |(R9+R10) / (R9-R10)| < 0.4.

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