Optical lens

Abstract

The application provides an optical lens, which comprises eight lenses with optical power, and sequentially comprises, along an optical axis from an object side to an imaging surface: a first lens with negative optical power, wherein an object side surface of the first lens is a concave surface and an image side surface of the first lens is a convex surface; a second lens with positive optical power, wherein an object side surface of the second lens is a convex surface; a third lens with negative optical power, wherein an image side surface of the third lens is a concave surface; a fourth lens with positive optical power, wherein an object side surface of the fourth lens is a concave surface and an image side surface of the fourth lens is a convex surface; a fifth lens with positive optical power, wherein an object side surface of the fifth lens is a convex surface and an image side surface of the fifth lens is a convex surface; a sixth lens with negative optical power, wherein an object side surface of the sixth lens is a concave surface and an image side surface of the sixth lens is a concave surface; a seventh lens with negative optical power, wherein an object side surface of the seventh lens is a concave surface and an image side surface of the seventh lens is a concave surface; and an eighth lens with negative optical power. The optical lens provided by the application has one or more advantages such as long focus, large aperture, 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] At present, with the vigorous development of automobile auxiliary driving and automatic driving technology, vehicle-mounted cameras play a crucial role. Vehicle-mounted cameras are of various types, including interior, rear, front, side and all-around view cameras. Each type has unique functions and different application scenarios. For example, front wide-angle cameras are mainly used for accurately identifying close-range objects, and can provide key information for driving in urban road conditions and low-speed driving scenarios.

[0003] Front cameras are the core components of ADAS (Advanced Driver Assistance System). They not only undertake the task of distance measurement, but also accurately identify objects and clearly distinguish road markings. Therefore, the visual algorithms required for front cameras are extremely complex and have high technical thresholds. In order to fully utilize the performance of front cameras, it is urgent to develop an optical lens with excellent imaging effect. Only in this way can the front camera work stably and efficiently in complex driving environments and lay a solid foundation for the further development of automatic driving technology. SUMMARY

[0004] To solve the above problems, the present application aims to provide an optical lens with excellent imaging quality.

[0005] The technical solution adopted by the present application is as follows:

[0006] An optical lens, which comprises eight lenses with optical power, arranged in order along the optical axis from the object side to the imaging surface, comprising:

[0007] a first lens with negative optical power, whose object side surface is concave and whose image side surface is convex;

[0008] a second lens with positive optical power, whose object side surface is convex;

[0009] a third lens with negative optical power, whose image side surface is concave;

[0010] a fourth lens with positive optical power, whose object side surface is concave and whose image side surface is convex;

[0011] a fifth lens with positive optical power, whose object side surface is convex and whose image side surface is convex;

[0012] a sixth lens with negative optical power, whose object side surface is concave and whose image side surface is concave;

[0013] a seventh lens with negative optical power, whose object side surface is concave and whose image side surface is concave;

[0014] the eighth lens has negative refractive power;

[0015] wherein a combined focal length f12 of the first lens and the second lens and a combined focal length f345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -0.85 < f12 / f345678 < 0.

[0016] It is further preferred that an overall optical length TTL of the optical lens and an effective focal length f of the optical lens satisfy: 1.5 < TTL / f < 1.8; the overall optical length TTL of the optical lens and a real image height IH corresponding to a maximum field of view angle of the optical lens satisfy: 2.6 < TTL / IH < 3.2.

[0017] It is further preferred that a real image height IH corresponding to a maximum field of view angle of the optical lens and an effective focal length f of the optical lens satisfy: 0.5 < IH / f < 0.6; a half entrance pupil 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 a maximum field of view angle FOV of the optical lens satisfy: 3.8 < d1 / (IH / 2) / Tan(FOV / 2) < 4.5.

[0018] It is further preferred that a focal length f1 of the first lens and an effective focal length f of the optical lens satisfy: -1.9 < f1 / f < -1.2; a radius of curvature R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -0.5 < R1 / f < -0.2; a radius of curvature R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: -0.75 < R2 / f < -0.3.

[0019] It is further preferred that a focal length f2 of the second lens and an effective focal length f of the optical lens satisfy: 0.5 < f2 / f < 0.9; a focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -3 < f3 / f < -0.8.

[0020] It is further preferred that a focal length f4 of the fourth lens and an effective focal length f of the optical lens satisfy: 1.3 < f4 / f < 2.3; a radius of curvature R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -5 < R7 / f < -3.2; a radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -1 < R8 / f < -0.6.

[0021] It is further preferred that the focal length f7 of the seventh lens satisfies -3.2 < f7 / f < -1.3, the radius of curvature R13 of the object side surface of the seventh lens satisfies -5.5 < R13 / f < -1.6, and the radius of curvature R14 of the image side surface of the seventh lens satisfies 1.8 < R14 / f < 4.3.

[0022] It is further preferred that the combined focal length f12 of the first lens and the second lens satisfies 0.6 < f12 / f < 1.6, and the combined focal length f345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfies -180 < f345678 / f < -0.8.

[0023] It is further preferred that the combined focal length f56 of the fifth lens and the sixth lens satisfies 1.2 < f56 / f < 8, the focal length f5 of the fifth lens satisfies -1.25 < f5 / f6 < -0.65, and the fifth lens and the sixth lens are cemented to form a cemented lens.

[0024] It is further preferred that the combined focal length f12 of the first lens and the second lens satisfies 0.6 < f12 / f1234 < 1.25, and the combined focal length f56 of the fifth lens and the sixth lens satisfies -7 < f56 / f5678 < -0.3.

[0025] 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 of long focal length, large aperture, high imaging quality, etc. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and / or additional aspects and advantages of the application will become apparent and be readily understood from the following description, taken in conjunction with the following drawings, in which:

[0027] Figure 1 FIG. 1 is a structural schematic diagram of an optical lens according to an embodiment of the application.

[0028] Figure 2 FIG. 2 is an MTF curve diagram of the optical lens according to the embodiment of the application.

[0029] Figure 3 Structure diagram of the optical lens in Embodiment 2 of the present application.

[0030] Figure 4 MTF curve diagram of the optical lens in Embodiment 2 of the present application.

[0031] Figure 5 Structure diagram of the optical lens in Embodiment 3 of the present application.

[0032] Figure 6 MTF curve diagram of the optical lens in Embodiment 3 of the present application.

[0033] Figure 7 Structure diagram of the optical lens in Embodiment 4 of the present application.

[0034] Figure 8 MTF curve diagram of the optical lens in Embodiment 4 of the present application.

[0035] Figure 9 Structure diagram of the optical lens in Embodiment 5 of the present application.

[0036] Figure 10 MTF curve diagram of the optical lens in Embodiment 5 of the present application.

[0037] Figure 11 Structure diagram of the optical lens in Embodiment 6 of the present application.

[0038] Figure 12 MTF curve diagram of the optical lens in Embodiment 6 of the present application.

[0039] Figure 13 Structure diagram of the optical lens in Embodiment 7 of the present application.

[0040] Figure 14 MTF curve diagram of the optical lens in Embodiment 7 of the present application.

[0041] The following detailed description will further describe the present application with reference to the above-mentioned drawings. DETAILED DESCRIPTION

[0042] For a better understanding of the present application, various aspects of the present application will be described in more detail below with reference to the accompanying drawings. It is to be understood that the detailed description is merely descriptive of embodiments of the present application and is not intended to limit the scope of the present application in any way. Throughout the description, like reference numerals refer to like elements. The expression “and / or” includes any and all combinations of one or more of the associated listed items.

[0043] It should be noted that the terms first, second, third, etc. in the present specification are used only to distinguish one feature from another, and do not denote any limitation on the features. Thus, the first lens discussed below can also be referred to as a second lens or a third lens without departing from the teachings of the present application.

[0044] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0045] In the present specification, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the image plane is referred to as the image side surface of the lens.

[0046] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, mean that there are 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 groups thereof. Furthermore, when describing the embodiments of the present application, the use of "may" means that one or more embodiments of the present application. Also, the word "exemplary" is intended to mean an example or an illustration.

[0047] Unless otherwise defined, all terms used in this specification, including technical and scientific terms, 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 in this specification.

[0048] 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.

[0049] 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.

[0050] In some embodiments, the first lens can have negative optical power, the object side surface thereof can be a concave surface, and the image side surface thereof can be a convex surface. The second lens can have positive optical power, the object side surface thereof can be a convex surface, and the image side surface thereof can be a convex surface or a concave surface. The third lens can have negative optical power, the object side surface thereof can be a concave surface or a convex surface, and the image side surface thereof can be a concave surface. The fourth lens can have positive optical power, the object side surface thereof can be a concave surface, and the image side surface thereof can be a convex surface. The fifth lens can have 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 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 seventh lens can have 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 negative optical power, the object side surface thereof can be a concave surface or a convex surface, and the image side surface thereof can be a convex surface or a concave surface.

[0051] In some embodiments, the optical lens can further comprise a diaphragm, which can be arranged between the first lens and the second lens. It can be understood that the diaphragm is used to limit the amount of light to change the brightness of the imaging.

[0052] In some embodiments, the optical lens can further comprise a filter and a protective glass, which are sequentially arranged along the optical axis between the eighth lens and the imaging surface. 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. The protective glass plays a role in protecting the optical lens, preventing the photosensitive chip from being damaged, and can improve the impact resistance and scratch resistance of the optical lens, while having little effect on the imaging quality of the optical lens.

[0053] In some embodiments, the fifth lens and the sixth lens can be bonded to form a bonded lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens. In addition, the bonded 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.

[0054] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy -0.85 < f12 / f345678 < 0. Satisfying the above range is helpful to correct the system chromatic aberration and improve the imaging performance. More specifically, -0.8 < f12 / f345678 < 0.

[0055] In some embodiments, the optical total track length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.5 < TTL / f < 1.8; 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: 2.6 < TTL / IH < 3.2. Satisfying the above ranges is conducive to achieving a balance between a small volume and a large image surface of the optical lens, so that the lens has a smaller total length. More specifically: 1.6 < TTL / f < 1.79; 2.8 < TTL / IH < 3.14.

[0056] 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: 0.5 < IH / f < 0.6; 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: 3.8 < d1 / (IH / 2) / Tan(FOV / 2) < 4.5. Satisfying the above ranges controls the image height and focal length of the optical lens within a reasonable range, which helps the optical lens to have a large image surface and improve the imaging quality. At the same time, the overall geometry of the optical lens can be reasonably arranged to improve its structural stability. More specifically: 0.56 < IH / f < 0.59; 3.87 < d1 / (IH / 2) / Tan(FOV / 2) < 4.5.

[0057] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.9 < f1 / f < -1.2; the object side surface curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: -0.5 < R1 / f < -0.2; the image side surface curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: -0.75 < R2 / f < -0.3. Satisfying the above ranges reasonably limits the refractive power ratio and surface shape of the first lens, which can collect a large amount of 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 angle. More specifically: -1.75 < f1 / f < -1.29; -0.45 < R1 / f < -0.24; -0.69 < R2 / f < -0.37.

[0058] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.5 < f2 / f < 0.9; the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -3 < f3 / f < -0.8. Satisfying the above ranges can effectively balance the aberration of the lens and improve the imaging quality. More specifically: 0.56 < f2 / f < 0.85; -2.85 < f3 / f < -0.85.

[0059] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3 < f4 / f < 2.3; 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: -5 < R7 / f < -3.2; 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: -1 < R8 / f < -0.6. By reasonably limiting the power ratio and the surface shape of the fourth lens, the spherical aberration can be optimized to achieve high-quality imaging when the above ranges are satisfied. More specifically, 1.42 < f4 / f < 2.09; -4.55 < R7 / f < -3.53; and -0.94 < R8 / f < -0.69.

[0060] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -3.2 < f7 / f < -1.3; the radius of curvature R13 of the object side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -5.5 < R13 / f < -1.6; and the radius of curvature R14 of the image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: 1.8 < R14 / f < 4.3. By reasonably limiting the power ratio and the surface shape of the seventh lens, the aberration generated at the front end of the lens can be effectively corrected, and the imaging quality of the lens can be improved when the above ranges are satisfied. More specifically, -2.92 < f7 / f < -1.43; -5.05 < R13 / f < -1.69; and 1.91 < R14 / f < 4.

[0061] In some embodiments, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 0.6 < f12 / f < 1.6; and the combined focal length f345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: -180 < f345678 / f < -0.8. The aberration correction difficulty of the lens can be reduced, and the imaging quality of the optical lens can be improved when the above ranges are satisfied. More specifically, 0.68 < f12 / f < 1.47; and -173.34 < f345678 / f < -0.87.

[0062] In some embodiments, the combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: 1.2 < f56 / f < 8; the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.25 < f5 / f6 < -0.65; and the fifth lens and the sixth lens are cemented to form a cemented lens. The assembly sensitivity of the optical lens can be reduced, and the processing difficulty of the optical lens can be reduced, and the assembly yield can be improved when the above ranges are satisfied. More specifically, 1.33 < f56 / f < 7.8; and -1.16 < f5 / f6 < -0.69.

[0063] In some embodiments, a combined focal length f12 of the first lens and the second lens and a combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: 0.6 < f12 / f1234 < 1.25; a combined focal length f56 of the fifth lens and the sixth lens and a combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -7 < f56 / f5678 < -0.3. Satisfying the above ranges is beneficial to improving the field curvature so that all the details of the full image fall on the same focal plane. More specifically, 0.63 < f12 / f1234 < 1.16; -6.8 < f56 / f5678 < -0.31.

[0064] In some embodiments, a maximum field of view FOV of the optical lens and an aperture value Fno of the optical lens satisfy: 18° < FOV / Fno < 19°. Satisfying the above range reasonably limits the ratio of the field of view and the aperture value, which can collect light rays of a large angle and obtain good imaging quality. More specifically, 18.3° < FOV / Fno < 18.4°.

[0065] In some embodiments, a real image height IH corresponding to the maximum field of view of the optical lens and an entrance pupil diameter EPD of the optical lens satisfy: 0.9 < IH / EPD < 1. Satisfying the above range reasonably limits the ratio of the image height and the entrance pupil diameter, which is beneficial to increasing the light throughput so that the brightness of the peripheral field of view and the central field of view is more uniform. More specifically, 0.96 < IH / EPD < 0.99.

[0066] In some embodiments, a back focal length BFL of the optical lens and an effective focal length f of the optical lens satisfy: 0.15 < BFL / f < 0.28. Satisfying the above range limits the optical lens to have a suitable back focus, which facilitates reasonable arrangement of the positions of the lenses and reduces the difficulty of processing and assembly.

[0067] In some embodiments, a focal length f5 of the fifth lens and an effective focal length f of the optical lens satisfy: 0.4 < f5 / f < 0.6; a radius of curvature R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 0.6 < R9 / f < 1.5; a radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -0.55 < R10 / f < -0.35. Satisfying the above ranges reasonably limits the refractive power ratio and the surface shape of the fifth lens, which helps to gently change the light ray trend of the front end lens, corrects the aberration generated by the front end lens, and improves the imaging quality. More specifically, 0.45 < f5 / f < 0.59; 0.62 < R9 / f < 1.45; -0.52 < R10 / f < -0.4.

[0068] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -0.8 < f6 / f < -0.4. Satisfying the above range, the proportion 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: -0.78 < f6 / f < -0.42.

[0069] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -5.4 < f8 / f < -1. Satisfying the above range, the proportion of the refractive power of the eighth lens is reasonably limited, which can optimize the spherical aberration and coma and is beneficial to high-resolution imaging. More specifically: -4.95 < f8 / f < -1.09.

[0070] In some embodiments, the object side surface radius of curvature R1 of the first lens and the image side surface radius of curvature R2 of the first lens satisfy: -0.3 < (R1-R2) / (R1+R2) < -0.1; the object side surface radius of curvature R7 of the fourth lens and the image side surface radius of curvature R8 of the fourth lens satisfy: 0.5 < (R7-R8) / (R7+R8) < 0.8; the object side surface radius of curvature R13 of the seventh lens and the image side surface radius of curvature R14 of the seventh lens satisfy: |(R13+R14) / (R13-R14)| < 0.5. Satisfying the above range, the aberration of the optical lens can be corrected, and the light ray trend passing through the first, fourth and seventh lenses is stable, and the tolerance sensitivity of the optical lens is reduced. More specifically: -0.24 < (R1-R2) / (R1+R2) < -0.18; 0.58 < (R7-R8) / (R7+R8) < 0.7; -0.17 < (R13+R14) / (R13-R14) < 0.45.

[0071] In some embodiments, the optical lens satisfies the following conditional expressions: 20mm < f < 22mm; 30° < FOV < 32°; 12mm < EPD < 13mm; 33mm < TTL < 38mm; 1.5 < Fno < 1.9; 12mm < IH < 12.5mm; 21° < CRA < 26°; 3mm < BFL < 6mm. 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 long focal length, large aperture, high imaging quality, etc. More specifically: 20.93mm < f < 21.29mm; 31.1° < FOV < 31.3°; 12.31mm < EPD < 12.53mm; 33.9mm < TTL < 37.87mm; 1.65 < Fno < 1.75; 12mm < IH < 12.2mm; 21.21° < CRA < 25.1°; 3.26mm < BFL < 5.71mm.

[0072] 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 optical lens provided by the present application can adopt a full-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0073] 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 a spherical structure, an 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 achieving lens miniaturization. More specifically, the first lens, the second lens, and the eighth lens of the present application adopt an aspherical lens, and the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens adopt a spherical lens.

[0074] In various embodiments of the present application, when the lens adopts an aspherical lens, each aspherical surface shape of the optical lens satisfies the following equation:

[0075] ;

[0076] Wherein, z is the distance of the curved surface and the curved surface vertex 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 curved surface vertex, K is the quadratic curved surface coefficient, B, C, D, E, F are the fourth order, sixth order, eighth order, tenth order, twelfth order curved surface coefficients respectively.

[0077] 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, substitution, 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.

[0078] Embodiment 1

[0079] 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 diaphragm ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter G1 and a protective glass G2.

[0080] The first lens L1 has negative focal power, the object side S1 thereof is a concave surface, and the image side S2 thereof is a convex surface;

[0081] The second lens L2 has positive focal power, the object side S3 thereof is a convex surface, and the image side S4 thereof is a convex surface;

[0082] The third lens L3 has negative focal power, the object side S5 thereof is a concave surface, and the image side S6 thereof is a concave surface;

[0083] The fourth lens L4 has positive focal power, the object side S7 thereof is a concave surface, and the image side S8 thereof is a convex surface;

[0084] The fifth lens L5 has positive focal power, the object side S9 thereof is a convex surface, and the image side thereof is a convex surface;

[0085] The sixth lens L6 has negative focal power, the object side thereof is a concave surface, and the image side S11 thereof is a concave surface;

[0086] The fifth lens L5 and the sixth lens L6 constitute a cemented lens group, that is, the cemented surface of the image side of the fifth lens L5 and the object side of the sixth lens L6 is S10;

[0087] The seventh lens L7 has negative focal power, the object side S12 thereof is a concave surface, and the image side S13 thereof is a concave surface;

[0088] The eighth lens L8 has negative refractive power, the object side S14 is a concave surface, and the image side S15 is a convex surface;

[0089] The object side S16 and the image side S17 of the filter G1 are both flat surfaces;

[0090] The object side S18 and the image side S19 of the protective glass G2 are both flat surfaces;

[0091] The imaging surface S20 is a flat surface.

[0092] The first lens L1, the second lens L2, and the eighth lens L8 are glass aspheric lenses, and the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are glass spherical lenses.

[0093] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0094] Table 1-1

[0095]

[0096] The surface type parameters of the aspheric lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0097] Table 1-2

[0098]

[0099] In this embodiment, the MTF curve of the optical lens 100 is shown in Figure 2 .

[0100] 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. As can be seen from the figure, 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.

[0101] Embodiment 2

[0102] 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 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.

[0103] The related parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0104] Table 2-1

[0105]

[0106] The surface type parameters of the aspheric lens of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0107] Table 2-2

[0108]

[0109] In this embodiment, the MTF curve of the optical lens 200 is shown in Figure 4 From Figure 4 it can be seen 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.

[0110] Embodiment 3

[0111] Please refer to Figure 5 , which is a structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present application. Compared with Embodiment 1, the main difference is that the object side S14 of the eighth lens L8 is a convex surface, and the image side S15 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0112] The related parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0113] Table 3-1

[0114]

[0115] The surface type parameters of the aspheric lens of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0116] Table 3-2

[0117]

[0118] In this embodiment, the MTF curve of the optical lens 300 is shown in Figure 6 From Figure 6As 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.

[0119] Example 4

[0120] 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 image side S4 of the second lens L2 is concave; the object side S14 of the eighth lens L8 is convex and the image side S15 is concave; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0121] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0122] Table 4-1

[0123]

[0124] The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0125] Table 4-2

[0126]

[0127] In this embodiment, the MTF curve of the optical lens 400 is as follows: Figure 8 As shown. From Figure 8 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.

[0128] Example 5

[0129] Please see Figure 9 The figure shows a schematic diagram of the structure of the optical lens 500 provided in Embodiment 5 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side S5 of the third lens L3 is a convex surface; the image side S15 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.

[0130] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0131] Table 5-1

[0132]

[0133] The surface profile parameters of the aspherical lenses of the optical lens 500 in Embodiment 5 are shown in Table 5-2.

[0134] Table 5-2

[0135]

[0136] In this embodiment, the MTF curve of the optical lens 500 is shown in Figure 10 It can be seen from Figure 10 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.

[0137] Embodiment 6

[0138] 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 object side S5 of the third lens L3 is a convex surface; the object side S14 of the eighth lens L8 is a convex surface, and the image side S15 is a concave surface; the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0139] The related parameters of each lens in the optical lens 600 in Embodiment 6 are shown in Table 6-1.

[0140] Table 6-1

[0141]

[0142] The surface profile parameters of the aspherical lenses of the optical lens 600 in Embodiment 6 are shown in Table 6-2.

[0143] Table 6-2

[0144]

[0145] In this 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 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.

[0146] Embodiment 7

[0147] 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 S4 of the second lens L2 is a concave surface; the object side S5 of the third lens L3 is a convex 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.

[0148] The related parameters of each lens in the optical lens 700 in Embodiment 7 are shown in Table 7-1.

[0149] Table 7-1

[0150]

[0151] The surface type parameters of the aspherical lens of the optical lens 700 in Embodiment 7 are shown in Table 7-2.

[0152] Table 7-2

[0153]

[0154] In this embodiment, the MTF curve of the optical lens 700 is shown in Figure 14 . As can be seen from Figure 14 , 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.

[0155] Please refer to Table 8-1 and Table 8-2, which are the optical characteristics corresponding to each of the above 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 condition in each embodiment.

[0156] Table 8-1

[0157]

[0158] Table 8-2

[0159]

[0160] In summary of the above embodiments, the optical lens provided by the present 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 long focal length, large aperture, high imaging quality, etc.

[0161] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0162] The above-described embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but cannot be understood as a limitation on the patent scope of the present application. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the patent protection scope 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 concave surface, and the image side surface of which is a convex surface; a second lens with positive refractive power, the object side surface of which is a convex surface; a third lens with negative refractive power, 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 concave 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 negative refractive power, the object side surface of which is a concave surface, and the image side surface of which is a concave 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 negative refractive power; wherein the combined focal length f12 of the first lens and the second lens and the combined focal length f345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -0.85 < f12 / f345678 < 0.

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: 1.5 < TTL / f < 1.8; the total optical 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: 2.6 < TTL / IH < 3.

2.

3. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 0.5 < IH / f < 0.6; 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: 3.8 < d1 / (IH / 2) / Tan(FOV / 2) < 4.

5.

4. The optical lens of claim 1, wherein, The focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.9 < f1 / f < -1.2; the object side surface curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: -0.5 < R1 / f < -0.2; the image side surface curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: -0.75 < R2 / f < -0.

3.

5. 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: 0.5 < f2 / f < 0.9; the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -3 < f3 / f < -0.

8.

6. The optical lens of claim 1, wherein, The focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3 < f4 / f < 2.3; the object side surface curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: -5 < R7 / f < -3.2; the image side surface curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -1 < R8 / f < -0.

6.

7. 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: -3.2 < f7 / f < -1.3; 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: -5.5 < R13 / f < -1.6; 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: 1.8 < R14 / f < 4.

3.

8. The optical lens of claim 1, wherein, A combined focal length f12 of the first lens and the second lens and an effective focal length f of the optical lens satisfy: 0.6 < f12 / f < 1.6; and a combined focal length f345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: -180 < f345678 / f < -0.

8.

9. The optical lens of claim 1, wherein, A combined focal length f56 of the fifth lens and the sixth lens and an effective focal length f of the optical lens satisfy: 1.2 < f56 / f < 8; and a focal length f5 of the fifth lens and a focal length f6 of the sixth lens satisfy: -1.25 < f5 / f6 < -0.

65.

10. The optical lens of claim 1, wherein, A combined focal length f12 of the first lens and the second lens and a combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: 0.6 < f12 / f1234 < 1.25; and a combined focal length f56 of the fifth lens and the sixth lens and a combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -7 < f56 / f5678 < -0.3.

Images