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 fourth lens has positive focal power; 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, and the image side surface of the sixth lens is a convex surface; the object side surface of the seventh lens is a concave surface, and the image side surface of the seventh lens is a concave surface; 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] Fish-eye lenses have super-wide-angle shooting characteristics, and can accommodate more and wider scenes in the actual shooting picture, and can meet the shooting of some large scene range pictures, and are widely used in the fields of action cameras, unmanned aerial vehicles, panoramic monitoring and the like. However, the existing fish-eye lens devices still have many deficiencies, for example, the field angle of the lens is increased, which leads to difficulty in system aberration correction and decline in imaging quality; the lens size is long and bulky, and the like. Therefore, it is necessary to develop an optical lens having one or more advantages of large field angle, 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 having the advantage of excellent imaging quality.

[0004] The technical scheme adopted by the present application is as follows: An optical lens, having a total of eight lenses with optical power, comprises, in order from the object side to the image plane along the optical axis: 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 near the optical axis and whose image side surface is a concave surface; a fourth lens with positive optical power; 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, whose image side surface is a convex surface; a seventh lens with negative optical power, whose object side surface is a concave surface and whose image side surface is a concave surface; 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<(R5-R6) / (R5+R6)<0.9, and the object side surface curvature radius R13 of the seventh lens and the image side surface curvature radius R14 of the seventh lens satisfy |(R13+R14) / (R13-R14)|<0.9.

[0005] 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: 17 < TTL / f < 31; 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: 6 < TTL / IH < 15.

[0006] It is further preferred that 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: 3.5 < IH / EPD < 7.8.

[0007] It is further preferred that 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: 1.8 < 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 < 3.4.

[0008] It is further preferred that 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: 17 < 180°×TTL / (IH / 2) / (FOV / 2) < 49; the half light entrance radius d1 of the object side surface of the first 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: -6.5 < d1 / (IH / 2) / Tan(FOV / 2) < -2.1.

[0009] It is further preferred that the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -10 < 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: 6 < R3 / f < 100; 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 < R4 / f < 5.

[0010] It is further preferred that the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -300 < f3 / f < -6.5; 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; 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 < 7.5.

[0011] It is further preferred that the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 3.2 < f5 / f < 10.5; the object side surface curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: 3.8 < R9 / f < 12; and the image side surface curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -10 < R10 / f < -2.9.

[0012] It is further preferred that the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -2.75 < f7 / f < -1.5; the object side surface curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -5 < R13 / f < -1.1; and the image side surface curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 3 < R14 / f < 27.

[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: 0.4 < (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: 0 < (R9+R10) / (R9-R10) < 0.3.

[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 still another embodiment of the application.

[0020] Figure 6The MTF curve diagram of the optical lens in embodiment 3 of the present application.

[0021] Figure 7 The structural schematic diagram of the optical lens in embodiment 4 of the present application.

[0022] Figure 8 The MTF curve diagram of the optical lens in embodiment 4 of the present application.

[0023] Figure 9 The structural schematic diagram of the optical lens in embodiment 5 of the present application.

[0024] Figure 10 The MTF curve diagram of the optical lens in embodiment 5 of the present application.

[0025] Figure 11 The structural schematic diagram of the optical lens in embodiment 6 of the present application.

[0026] Figure 12 The MTF curve diagram of the optical lens in embodiment 6 of the present application.

[0027] Figure 13 The structural schematic diagram of the optical lens in embodiment 7 of the present application.

[0028] Figure 14 The MTF curve diagram of the optical lens in embodiment 7 of the present application.

[0029] Figure 15 The structural schematic diagram of the optical lens in embodiment 8 of the present application.

[0030] Figure 16 The MTF curve diagram of the optical lens in embodiment 8 of the present application.

[0031] Figure 17 The structural schematic diagram of the optical lens in embodiment 9 of the present application.

[0032] Figure 18 The MTF curve diagram of the optical lens in embodiment 9 of the present application.

[0033] Figure 19 The structural schematic diagram of the optical lens in embodiment 10 of the present application.

[0034] Figure 20 The MTF curve diagram of the optical lens in embodiment 10 of the present application.

[0035] Figure 21 The structural schematic diagram of the optical lens in embodiment 11 of the present application.

[0036] Figure 22 The MTF curve diagram of the optical lens in embodiment 11 of the present application.

[0037] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0038] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0039] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0040] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0041] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0042] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0043] 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 will 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.

[0044] It should be noted that the embodiments and features of 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 accompanying drawings and in conjunction with the embodiments.

[0045] The optical lens provided by the embodiment 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 surface 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.

[0046] In some embodiments, the first lens can have a negative optical power, the object side surface thereof can be a convex surface, and the image side surface thereof can be a concave surface. The second lens can have a negative optical power, the object side surface thereof can be a convex surface, and the image side surface thereof can be a concave surface. The third lens can have a negative optical power, the object side surface thereof can be a convex surface at the near optical axis, and the image side surface thereof can be a concave surface. The fourth lens can have a positive optical power, the object side surface thereof can be a convex surface or a concave surface, and the image side surface thereof can be a convex surface or a concave surface. The fifth lens can have a positive optical power, the object side surface thereof can be a convex surface, and the image side surface thereof can be a convex surface. The sixth lens can have a positive optical power, the object side surface thereof can be a convex surface or a concave surface, and the image side surface thereof can be a convex surface. The seventh lens can have a negative optical power, the object side surface thereof can be a concave surface, and the image side surface thereof can be a concave surface. The eighth lens can have a positive optical power, the object side surface thereof can be a convex surface or a concave surface, and the image side surface thereof can be a convex surface or a concave surface.

[0047] In some embodiments, the optical lens can further comprise 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.

[0048] In some embodiments, the optical lens can further comprise a filter, which is arranged between the eighth lens and the imaging surface along the optical axis. The filter is used to filter out the interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting the normal imaging.

[0049] In some embodiments, the sixth lens and the seventh lens can be glued to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the sensitivity of the optical lens to the eccentricity, balance the aberration of the optical lens, and improve the imaging quality of the optical lens. In addition, the glued lens 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.

[0050] In some embodiments, the radius of curvature R5 of the object-side surface of the third lens and the radius of curvature R6 of the image-side surface of the third lens satisfy: 0 < (R5-R6) / (R5+R6) < 0.9; the radius of curvature R13 of the object-side surface of the seventh lens and the radius of curvature R14 of the image-side surface of the seventh lens satisfy: |(R13+R14) / (R13-R14)| < 0.9. Satisfying the above range is conducive to adjusting the light path and making the optical lens have a large field of view. More specifically: 0.06 < (R5-R6) / (R5+R6) < 0.9; -0.9 < (R13+R14) / (R13-R14) < 0.1.

[0051] In some embodiments, the total track length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 17 < TTL / f < 31; 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: 6 < TTL / IH < 15. Satisfying the above range can effectively limit the length of the lens, which is conducive to the miniaturization of the optical lens. More specifically: 18.58 < TTL / f < 29.9; 6.14 < TTL / IH < 13.73.

[0052] In some embodiments, 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: 3.5 < IH / EPD < 7.8. Satisfying the above range reasonably limits the ratio of the field of view and the aperture value, which is conducive to improving the light amount of the lens and enabling the lens to have high-definition imaging in a dark 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: 95.64° < FOV / Fno < 110.1°; 3.84 < IH / EPD < 7.11.

[0053] In some embodiments, 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: 1.8 < 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 < 3.4. Satisfying the above range can achieve a larger field of view and ensure a large depth of field. At the same time, limiting the optical lens to have a suitable back focus facilitates the reasonable arrangement of the positions of the lenses and reduces the difficulty of processing and assembly. More specifically: 1.92 < IH / f < 3.24; 1.7 < BFL / f < 3.16.

[0054] 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° x TTL / (IH / 2) / (FOV / 2) < 49; the half light entrance radius d1 of the object side of the first 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: -6.5 < 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, the overall geometry of the optical lens can be reasonably arranged, and the structural stability thereof is improved. More specifically: 18.43 < 180° x TTL / (IH / 2) / (FOV / 2) < 44.92; -6.01 < d1 / (IH / 2) / Tan(FOV / 2) < -2.36.

[0055] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -10 < f2 / f < -3; the object side curvature radius R3 of the second lens and the effective focal length f of the optical lens satisfy: 6 < R3 / f < 100; the image side curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: 2 < R4 / f < 5. Satisfying the above range reasonably limits the power ratio and the surface shape of the second lens, which can further diverge the light rays and improve the field of view angle of the imaging system. More specifically: -9.24 < f2 / f < -3.34; 6.37 < R3 / f < 91.38; 2.25 < R4 / f < 4.71.

[0056] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -300 < f3 / f < -6.5; the object side 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 curvature radius R6 of the third lens and the effective focal length f of the optical lens satisfy: 2.3 < R6 / f < 7.5. Satisfying the above range reasonably limits the power ratio and the surface shape of the third lens, 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 of view aberration. More specifically: -292.43 < f3 / f < -7; 4.16 < R5 / f < 62.36; 2.56 < R6 / f < 7.01.

[0057] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 3.2 < f5 / f < 10.5; the object-side surface curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: 3.8 < R9 / f < 12; and the image-side surface curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -10 < R10 / f < -2.9. Satisfying the above ranges, the proportion of refractive power and the surface shape of the fifth lens 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 < 9.83; 4.14 < R9 / f < 11.35; and -9.78 < R10 / f < -3.17.

[0058] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -2.75 < f7 / f < -1.5; the object-side surface curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -5 < R13 / f < -1.1; and the image-side surface curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 3 < R14 / f < 27. Satisfying the above ranges, the proportion of refractive power and the surface shape of the seventh lens are reasonably limited, which can effectively correct the aberrations generated at the front end of the lens and improve the imaging quality of the lens. More specifically, -2.51 < f7 / f < -1.63; -4.69 < R13 / f < -1.21; and 3.26 < R14 / f < 24.9.

[0059] 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: 0.4 < (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: 0 < (R9+R10) / (R9-R10) < 0.3. 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, 0.42 < (R3-R4) / (R3+R4) < 0.95; and 0.05 < (R9+R10) / (R9-R10) < 0.3.

[0060] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -70 < f1 / f < -6.2. Satisfying the above ranges, the proportion of refractive power of the first lens is reasonably limited, which can collect light at a large field of view to a greater extent, so that the light enters the rear optical system, increases the light flux, and improves the field of view. More specifically, -68.54 < f1 / f < -6.84.

[0061] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 5.2 < f4 / f < 14.5. Satisfying the above range, the ratio of the refractive power of the fourth lens is reasonably limited, which can converge light rays and correct the aberration problem caused by the first three negative focal length lenses. More specifically: 5.69 < f4 / f < 13.24.

[0062] 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 < 4.2. Satisfying the above range, the ratio of the refractive power of the sixth lens is reasonably limited, which can effectively improve the aberration of the edge field of view and improve the overall imaging quality of the optical lens. More specifically: 1.78 < f6 / f < 3.89.

[0063] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 3.6 < f8 / f < 70. Satisfying the above range, the ratio of the refractive power of the eighth lens is reasonably limited, which is beneficial to reduce the eccentricity sensitivity of the optical lens and improve the imaging resolution. More specifically: 3.9 < f8 / f < 64.87.

[0064] 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 < 4.2. Satisfying the above range, the ratio of the refractive power of the diaphragm rear lens group is limited, which is beneficial to correct the chromatic aberration and field curvature of the optical system, reduce the sensitivity, and reduce the difficulty of lens forming. More specifically: 2.98 < f5678 / f < 3.97.

[0065] In some embodiments, the optical lens satisfies the following conditional expressions: 0.5mm < f < 0.85mm; 210° < FOV < 250°; 0.2mm < EPD < 0.4mm; 12mm < TTL < 18mm; 1.9 < Fno < 2.4; 1.1mm < IH < 2.8mm; 10° < CRA < 30°; 1.1mm < BFL < 2.5mm. 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 angle of incidence at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. Satisfying the above ranges, the optical lens has one or more advantages such as short focal length, large field of view angle, high imaging quality, etc. More specifically, 0.54mm < f < 0.82mm; 219° < FOV < 241°; 0.24mm < EPD < 0.38mm; 12.7mm < TTL < 17.89mm; 1.99 < Fno < 2.31; 1.18mm < IH < 2.59mm; 10.26° < CRA < 29.1°; 1.14mm < BFL < 2.41mm.

[0066] 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 characteristic 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 cost performance.

[0067] 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 spherical lenses or aspherical lenses. 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 spherical lenses, and the third lens and the fifth lens adopt aspherical lenses.

[0068] 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 to the vertex of the curved surface in the direction of the optical axis, h is the distance of the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the coefficient of the quadratic surface, B, C, D, E, F, G, H are the coefficients of the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, sixteenth-order curved surface, respectively.

[0069] The application will be further described in the following embodiments. In each embodiment, the thickness, the radius of curvature, 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 the preferred embodiments of the application, but the embodiments of the application are not limited to the following embodiments only, any change, replacement, combination or simplification made without departing from the innovative points of the application should be regarded as equivalent replacement, and all are included in the protection scope of the application.

[0070] Embodiment 1 Please refer to Figure 1 , which is a structural schematic diagram of the optical lens 100 provided in the embodiment 1 of the application, the optical lens 100 includes, 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.

[0071] The first lens L1 has negative focal power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface; The second lens L2 has negative focal power, the object side surface S3 is a convex surface, and the image side surface S4 is a concave surface; The third lens L3 has negative focal power, the object side surface S5 is a convex surface at the near optical axis, and the image side surface S6 is a concave surface; The fourth lens L4 has positive focal power, the object side surface S7 is a convex surface, and the image side surface S8 is a convex surface; The fifth lens L5 has positive focal power, the object side surface S9 is a convex surface, and the image side surface S10 is a convex surface; The sixth lens L6 has positive focal power, the object side surface S11 is a convex surface, and the image side surface is a convex surface; The seventh lens L7 has negative focal power, the object side surface is a concave surface, and the image side surface S13 is a concave surface; The sixth lens L6 and the seventh lens L7 form a cemented lens group, that is, the cemented surface of the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7 is S12; The eighth lens L8 has positive focal power, the object side surface S14 is a convex surface, and the image side surface S15 is a convex surface; The object side surface S16 and the image side surface S17 of the filter G1 are both flat surfaces; The imaging surface S18 is a flat surface.

[0072] 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 glass spherical lenses, and the third lens L3 and the fifth lens L5 are plastic aspherical lenses.

[0073] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0074] Table 1-1 The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0075] Table 1-2 In this embodiment, the MTF curve of the optical lens 100 is shown in Figure 2 .

[0076] Figure 2 The MTF (Modulation Transfer Function) curve of 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 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 the case of low frequency and high frequency.

[0077] Embodiment 2 Please refer to Figure 3 , which is a structural schematic diagram of the optical lens 200 provided in Embodiment 2 of the application. Compared with Embodiment 1, the main difference is that the image side surface S15 of the eighth lens L8 is a concave surface, and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0078] The related parameters of the lenses in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0079] Table 2-1 The surface type parameters of the aspherical lenses of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0080] Table 2-2 In this embodiment, the MTF curve of the optical lens 200 is shown in Figure 4 . From Figure 4As 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.

[0081] Example 3 Please see Figure 5 The figure shows a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 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 image side surface S15 of the eighth lens L8 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0082] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0083] Table 3-1 The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0084] Table 3-2 In this embodiment, the MTF curve of the optical lens 300 is as follows: Figure 6 As shown. From Figure 6 As can be seen, the MTF value of this embodiment is above 0.4 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.

[0085] Example 4 Please see Figure 7 The figure shows a schematic diagram of the structure of the optical lens 400 provided in Embodiment 4 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S7 of the fourth lens L4 is concave; the image side surface S15 of the eighth lens L8 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0086] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0087] Table 4-1 The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0088] Table 4-2 In the embodiment, the MTF curve of the optical lens 400 is shown in Figure 8 From Figure 8 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 0-160 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.

[0089] Embodiment 5 Please refer to Figure 9 , which is a structural schematic diagram of the optical lens 500 provided in the embodiment 5 of the application. Compared with the embodiment 1, the main difference of the embodiment is that the image side S8 of the fourth lens L4 is a concave 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.

[0090] The related parameters of each lens in the optical lens 500 in the embodiment 5 are shown in Table 5-1.

[0091] Table 5-1 The surface type parameters of the aspheric lens of the optical lens 500 in the embodiment 5 are shown in Table 5-2.

[0092] Table 5-2 In the 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 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.

[0093] Embodiment 6 Please refer to Figure 11 , which is a structural schematic diagram of the optical lens 600 provided in the embodiment 6 of the application. Compared with the embodiment 1, the main difference of the embodiment is that the object side S14 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.

[0094] The related parameters of each lens in the optical lens 600 in the embodiment 6 are shown in Table 6-1.

[0095] Table 6-1 The surface shape parameters of the aspheric lenses of the optical lens 600 in Embodiment 6 are shown in Table 6-2.

[0096] Table 6-2 In the present embodiment, the MTF curve of the optical lens 600 is shown in Figure 12 It can be seen from Figure 12 that the MTF value of the present 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.

[0097] Embodiment 7 Please refer to Figure 13 , which is a structural schematic diagram of the optical lens 700 provided in Embodiment 7 of the present application. Compared with Embodiment 1, the main difference is that the image side surface S8 of the fourth lens L4 is a concave surface; 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 700 in Embodiment 7 are shown in Table 7-1.

[0099] Table 7-1 The surface shape parameters of the aspheric lenses of the optical lens 700 in Embodiment 7 are shown in Table 7-2.

[0100] Table 7-2 In the present embodiment, the MTF curve of the optical lens 700 is shown in Figure 14 It can be seen from Figure 14 that the MTF value of the present embodiment is above 0.6 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.

[0101] Embodiment 8 Please refer to Figure 15 , which is a structural schematic diagram of the optical lens 800 provided in Embodiment 8 of the present application. Compared with Embodiment 1, the main difference is that the object side surface S7 of the fourth lens L4 is a concave surface; the object side surface S11 of the sixth lens L6 is a concave surface; the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0102] The related parameters of each lens in the optical lens 800 in Embodiment 8 are shown in Table 8-1.

[0103] Table 8-1 The surface profile parameters of the aspherical lenses of the optical lens 800 in Embodiment 8 are shown in Table 8-2.

[0104] Table 8-2 In this embodiment, the MTF curve of the optical lens 800 is shown in Figure 16 From Figure 16 it can be seen that the MTF value of this embodiment is above 0.6 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.

[0105] Embodiment 9 Please refer to Figure 17 , which is a structural schematic diagram of the optical lens 900 provided in Embodiment 9 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 optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.

[0106] The related parameters of each lens in the optical lens 900 in Embodiment 9 are shown in Table 9-1.

[0107] Table 9-1 The surface profile parameters of the aspherical lenses of the optical lens 900 in Embodiment 9 are shown in Table 9-2.

[0108] Table 9-2 In this embodiment, the MTF curve of the optical lens 900 is shown in Figure 18 From Figure 18 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 both low and high frequency cases.

[0109] Embodiment 10 Please refer to Figure 19The diagram shown is a structural schematic of the optical lens 1000 provided in Embodiment 10 of the present invention. The main difference between this embodiment and Embodiment 1 is that the image-side surface S8 of the fourth lens L4 is concave, the object-side surface S11 of the sixth lens L6 is concave, and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0110] The relevant parameters of each lens in the optical lens 1000 in Example 10 are shown in Table 10-1.

[0111] Table 10-1 The surface profile parameters of the aspherical lens of the optical lens 1000 in Example 10 are shown in Table 10-2.

[0112] Table 10-2 In this embodiment, the MTF curve of the optical lens 1000 is as follows: Figure 20 As shown. From Figure 20 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.

[0113] Example 11 Please see Figure 21 The figure shown is a schematic diagram of the structure of the optical lens 1100 provided in Embodiment 11 of the present invention. The main difference between this embodiment and Embodiment 1 is that: the image side surface S8 of the fourth lens L4 is concave; the object side surface S11 of the sixth lens L6 is concave; the image side surface S15 of the eighth lens L8 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0114] The relevant parameters of each lens in the optical lens 1100 in Example 11 are shown in Table 11-1.

[0115] Table 11-1 The surface profile parameters of the aspherical lens of the optical lens 1100 in Example 11 are shown in Table 11-2.

[0116] Table 11-2 In this embodiment, the MTF curve of the optical lens 1100 is as follows: Figure 22 As shown. From Figure 22It can be seen 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 capability in the case of low frequency and high frequency.

[0117] Please refer to Table 12-1, Table 12-2, Table 12-3 and Table 12-4, which are the optical properties corresponding to the above-mentioned embodiments, including the effective focal length f, 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.

[0118] Table 12-1 Table 12-2 Table 12-3 Table 12-4 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, high imaging quality, etc.

[0119] 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.

[0120] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled persons 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 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, 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; 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, the image side surface of which is a convex surface; a seventh lens with negative refractive power, the object side surface of which is a concave surface, and the image side surface of which is a concave surface; 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 < (R5-R6) / (R5+R6) < 0.9; the object side surface curvature radius R13 of the seventh lens and the image side surface curvature radius R14 of the seventh lens satisfy: |(R13+R14) / (R13-R14)| < 0.

9.

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: 17 < TTL / f < 31; 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: 6 < TTL / IH < 15.

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: 3.5 < 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: 1.8 < 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.

4.

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) < 49; the half light entrance radius d1 of the object side surface of the first 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: -6.5 < 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: -10 < 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: 6 < R3 / f < 100; the image side surface curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: 2 < R4 / f < 5.

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: -300 < f3 / f < -6.5; 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 < 7.

5.

8. 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: 3.2 < f5 / f < 10.5; 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: 3.8 < R9 / f < 12; 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: -10 < R10 / f < -2.

9.

9. The optical lens of claim 1, wherein, A focal length f7 of the seventh lens and an effective focal length f of the optical lens satisfy: -2.75 < f7 / f < -1.5; a radius of curvature R13 of an object side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -5 < R13 / f < -1.1; and a radius of curvature R14 of an image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: 3 < R14 / f < 27.

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: 0.4 < (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: 0 < (R9+R10) / (R9-R10) < 0.3.

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