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 positive 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; the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a concave surface; the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface; the object side surface of the sixth lens is a concave surface, and the image side surface of the sixth lens is a concave 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 negative focal power. The optical lens provided by the invention has one or more advantages of 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] The front camera is the core component of the ADAS (Advanced Driver Assistance System). It not only undertakes the task of distance measurement, but also accurately identifies objects and clearly distinguishes road markings. Therefore, the visual algorithm required is extremely complex and the technical threshold is high. In order to fully exert the performance of the front camera, it is urgent to develop an optical lens with excellent imaging effect. Only in this way can it work stably and efficiently in complex driving environments and lay a solid foundation for the further development of automatic driving technology. SUMMARY

[0004] In view of the above problems, the purpose of the present application is to provide an optical lens with excellent imaging quality.

[0005] The technical scheme adopted by the present application is as follows: An optical lens, which comprises eight lenses with optical power, arranged along the optical axis from the object side to the imaging surface in the following order: a first lens with negative optical power, whose object side surface is concave and whose image side surface is convex; a second lens with positive optical power, whose object side surface is convex; a third lens with negative optical power, whose object side surface is concave and whose image side surface is concave; a fourth lens with positive optical power, whose object side surface is convex and whose image side surface is convex; a fifth lens with positive optical power, whose object side surface is convex and whose image side surface is convex; a sixth lens with negative optical power, whose object side surface is concave and whose image side surface is concave; a seventh lens with negative optical power, whose object side surface is concave and whose image side surface is concave; an eighth lens with negative optical power; wherein the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy the following condition: 0.75 < f12 / f < 1.8.

[0006] Further preferably, the total track length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.5 < TTL / f < 1.9; 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: 2.3 < TTL / IH < 3.4.

[0007] Further preferably, the real image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 0.9 < IH / EPD < 1.1; 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 < 0.7.

[0008] Further preferably, 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: 3.5 < d1 / (IH / 2) / Tan(FOV / 2) < 4.5; the combined focal length f12 of the first lens and the second lens and the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: 0.8 < f12 / f1234 < 1.8.

[0009] Further preferably, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2 < f1 / f < -1.35; the object side surface curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: -0.45 < R1 / f < -0.25; the image side surface curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: -0.7 < R2 / f < -0.4.

[0010] Further preferably, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.6 < f2 / f < 1; the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 0.5 < f4 / f < 0.7.

[0011] Further preferably, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -0.7 < f3 / f < -0.4; the object side surface curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: -4.8 < R5 / f < -2.7; the image side surface curvature radius R6 of the third lens and the effective focal length f of the optical lens satisfy: 0.35 < R6 / f < 0.55.

[0012] It is further preferred that a focal length f7 of the seventh lens satisfies -2.7 < f7 / f < -1, a radius of curvature R13 on an object side of the seventh lens satisfies -5.9 < R13 / f < -2.2, and a radius of curvature R14 on an image side of the seventh lens satisfies 0.9 < R14 / f < 5.4.

[0013] It is further preferred that a combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfies -0.85 < f1234 / f5678 < -0.25, and a combined focal length f34 of the third lens and the fourth lens satisfies 0 < f34 / f56 < 9.5.

[0014] It is further preferred that a radius of curvature R5 on an object side of the third lens satisfies 1.15 < (R5-R6) / (R5+R6) < 1.45, a radius of curvature R1 on an object side of the first lens satisfies -5.4 < (R1+R2) / (R1-R2) < -3.6, a radius of curvature R7 on an object side of the fourth lens satisfies -0.55 < (R7+R8) / (R7-R8) < -0.1, or a radius of curvature R13 on an object side of the seventh lens satisfies |(R13+R14) / (R13-R14)| < 0.7.

[0015] 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 and the like. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the following drawings, in which: Figure 1 FIG. 1 is a structural schematic diagram of an optical lens according to an embodiment of the present application.

[0017] Figure 2 FIG. 2 is an MTF curve diagram of the optical lens according to the embodiment of the present application.

[0018] Figure 3 FIG. 3 is a structural schematic diagram of an optical lens according to another embodiment of the present application.

[0019] Figure 4 MTF curve of the optical lens in Embodiment 2 of the present application.

[0020] Figure 5 Structure diagram of the optical lens in Embodiment 3 of the present application.

[0021] Figure 6 MTF curve of the optical lens in Embodiment 3 of the present application.

[0022] Figure 7 Structure diagram of the optical lens in Embodiment 4 of the present application.

[0023] Figure 8 MTF curve of the optical lens in Embodiment 4 of the present application.

[0024] Figure 9 Structure diagram of the optical lens in Embodiment 5 of the present application.

[0025] Figure 10 MTF curve of the optical lens in Embodiment 5 of the present application.

[0026] Figure 11 Structure diagram of the optical lens in Embodiment 6 of the present application.

[0027] Figure 12 MTF curve of the optical lens in Embodiment 6 of the present application.

[0028] The following detailed description will further describe the present application with reference to the above-mentioned drawings. DETAILED DESCRIPTION

[0029] For better understanding of the present application, various aspects of the present application will be described in more detail with reference to the drawings. It should be understood that these detailed descriptions are merely descriptive of embodiments of the present application and are not intended in any way to limit the scope of the present application. Throughout the specification, like reference numerals refer to like elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0030] It should be noted that in the present specification, the expressions first, second, third, etc. are merely used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, the first lens discussed below can also be referred to as the second lens or the third lens without departing from the teachings of the present application.

[0031] In the drawings, the thickness, size, and shape of the lenses have been exaggerated slightly 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.

[0032] In this document, the paraxial region refers to a region near the optical axis. If the 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 the lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the imaging surface is referred to as the image side surface of the lens.

[0033] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, mean the presence of stated features, elements, and / or components but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. In addition, when 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.

[0034] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that the terms should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0035] 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 drawings and in conjunction with the embodiments.

[0036] The optical lens provided by the embodiments of the present application comprises eight lenses with optical power, which are sequentially arranged along the optical axis from the object side to the imaging 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.

[0037] In some embodiments, the first lens may have negative optical power, its object-side surface may be concave, and its image-side surface may be convex. The second lens may have positive optical power, its object-side surface may be convex, and its image-side surface may be convex or concave. The third lens may have negative optical power, its object-side surface may be concave, and its image-side surface may be concave. The fourth lens may have positive optical power, its object-side surface may be convex, and its image-side surface may be convex. The fifth lens may have positive optical power, its object-side surface may be convex, and its image-side surface may be convex. The sixth lens may have negative optical power, its object-side surface may be concave, and its image-side surface may be concave. The seventh lens may have negative optical power, its object-side surface may be concave, and its image-side surface may be concave. The eighth lens may have negative optical power, its object-side surface may be concave or convex, and its image-side surface may be convex or concave.

[0038] In some embodiments, the optical lens may further include an aperture, which may be located between the first lens and the second lens. It is understood that the aperture is used to limit the amount of light entering to change the brightness of the image.

[0039] In some embodiments, the optical lens may further include a filter and a protective glass, positioned sequentially along the optical axis between the eighth lens element and the imaging plane. The filter is used to filter out interfering light, preventing it from reaching the imaging plane of the optical lens and affecting normal imaging. The protective glass protects the optical lens from damage to the photosensitive chip and improves the optical lens's impact and scratch resistance, while having little impact on the optical lens's imaging quality.

[0040] In some embodiments, the third lens and the fourth lens can be glued together to form a glued lens, and the fifth lens and the sixth lens can be glued together to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the decentration sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the difficulty of the processing technology of the optical lens and improving the assembly yield of the optical lens.

[0041] In some embodiments, the combined focal length f12 of the first lens and the second lens satisfies the effective focal length f of the optical lens: 0.75 <f12 / f<1.8。满足上述范围,能降低透镜的像差校正难度,提高光学镜头的成像质量。更为具体的是:0.81<f12 / f<1.68。

[0042] 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 < 1.9; 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: 2.3 < TTL / IH < 3.4. Satisfying the above ranges is beneficial 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: 1.62 < TTL / f < 1.88; 2.53 < TTL / IH < 3.31.

[0043] In some embodiments, the real image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 0.9 < IH / EPD < 1.1; 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 < 0.7. Satisfying the above ranges is beneficial to increasing the light quantity, so that the brightness of the peripheral field of view and the central field of view is more uniform. At the same time, controlling the image height and the focal length of the optical lens within a reasonable range is helpful to the optical lens having a large image surface and improving the imaging quality. More specifically: 0.95 < IH / EPD < 1.06; 0.56 < IH / f < 0.66.

[0044] In some embodiments, the light passing half-radii 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: 3.5 < d1 / (IH / 2) / Tan(FOV / 2) < 4.5; the combined focal length f12 of the first lens and the second lens and the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: 0.8 < f12 / f1234 < 1.8. Satisfying the above ranges is beneficial to reasonably arranging the overall geometry of the optical lens and improving the structural stability. At the same time, it is beneficial to realize low aberration and high resolution imaging. More specifically: 3.58 < d1 / (IH / 2) / Tan(FOV / 2) < 4.45; 0.91 < f12 / f1234 < 1.67.

[0045] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2 < f1 / f < -1.35; the object side surface curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: -0.45 < R1 / f < -0.25; and the image side surface curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: -0.7 < R2 / f < -0.4. Satisfying the above ranges, the proportion of the refractive power of the first lens and the surface shape thereof are reasonably limited, which can collect light at a large field of view to a large extent, so that the light enters the rear optical system, increases the light flux, and improves the field of view. More specifically, -1.86 < f1 / f < -1.39; -0.43 < R1 / f < -0.27; and -0.69 < R2 / f < -0.42.

[0046] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.6 < f2 / f < 1; and the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 0.5 < f4 / f < 0.7. Satisfying the above ranges, it is beneficial to achieve a larger amount of light, and increase the relative luminance. More specifically, 0.62 < f2 / f < 0.9; and 0.52 < f4 / f < 0.6.

[0047] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -0.7 < f3 / f < -0.4; the object side surface curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: -4.8 < R5 / f < -2.7; and the image side surface curvature radius R6 of the third lens and the effective focal length f of the optical lens satisfy: 0.35 < R6 / f < 0.55. Satisfying the above ranges, the proportion of the refractive power of the third lens and the surface shape thereof are reasonably limited, which can effectively balance the aberration of the lens, and improve the imaging quality. More specifically, -0.67 < f3 / f < -0.47; -4.42 < R5 / f < -2.92; and 0.37 < R6 / f < 0.53.

[0048] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -2.7 < f7 / f < -1; the object side surface curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -5.9 < R13 / f < -2.2; and the image side surface curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 0.9 < R14 / f < 5.4. Satisfying the above ranges, by reasonably limiting the proportion of the refractive power of the seventh lens and the surface shape thereof, the aberration generated at the front end of the lens can be effectively corrected, and the imaging quality of the lens is improved. More specifically, -2.63 < f7 / f < -1.07; -5.39 < R13 / f < -2.41; and 0.93 < R14 / f < 4.97.

[0049] In some embodiments, a combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and a combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -0.85 < f1234 / f5678 < -0.25; a combined focal length f34 of the third lens and the fourth lens and a combined focal length f56 of the fifth lens and the sixth lens satisfy: 0 < f34 / f56 < 9.5. Satisfying the above ranges can effectively correct chromatic aberration of the optical lens and reduce sensitivity to decentration. More specifically, -0.79 < f1234 / f5678 < -0.27; 0.02 < f34 / f56 < 8.82.

[0050] In some embodiments, a radius of curvature R5 of the object side surface of the third lens and a radius of curvature R6 of the image side surface of the third lens satisfy: 1.15 < (R5-R6) / (R5+R6) < 1.45; a radius of curvature R1 of the object side surface of the first lens and a radius of curvature R2 of the image side surface of the first lens satisfy: -5.4 < (R1+R2) / (R1-R2) < -3.6; a radius of curvature R7 of the object side surface of the fourth lens and a radius of curvature R8 of the image side surface of the fourth lens satisfy: -0.55 < (R7+R8) / (R7-R8) < -0.1; and a radius of curvature R13 of the object side surface of the seventh lens and a radius of curvature R14 of the image side surface of the seventh lens satisfy: |(R13+R14) / (R13-R14)| < 0.7. Satisfying the above ranges can correct aberration of the optical lens and ensure smooth light ray trend through the first, third, fourth and seventh lenses, thereby reducing tolerance sensitivity of the optical lens. More specifically, 1.25 < (R5-R6) / (R5+R6) < 1.36; -4.95 < (R1+R2) / (R1-R2) < -3.95; -0.51 < (R7+R8) / (R7-R8) < -0.14; and -0.35 < (R13+R14) / (R13-R14) < 0.65.

[0051] In some embodiments, a maximum field of view FOV of the optical lens and an aperture value Fno of the optical lens satisfy: 17° < FOV / Fno < 23°. Satisfying the above range can reasonably limit the ratio of the field of view and the aperture value, so as to collect light rays at a large angle and obtain good imaging quality. More specifically, 18.34° < FOV / Fno < 21°.

[0052] 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 < 0.29. Satisfying the above range can limit the optical lens to have a proper back focus, facilitate reasonable arrangement of positions of the lenses, and reduce processing and assembly difficulty.

[0053] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.5 < f5 / f < 0.7. Satisfying the above range, the ratio of the refractive power of the fifth lens is reasonably limited, which helps to flatten 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: 0.51 < f5 / f < 0.65.

[0054] 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 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: -0.78 < f6 / f < -0.49.

[0055] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -7 < f8 / f < -1.2. Satisfying the above range, the ratio of the refractive power of the eighth lens is reasonably limited, which is beneficial to increase the degree of divergence of light and realize large target surface imaging. More specifically: -6.88 < f8 / f < -1.32.

[0056] In some embodiments, the combined focal length f34 of the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 1.7 < f34 / f < 17.5; the third lens and the fourth lens are cemented to form a cemented lens. Satisfying the above range is beneficial to realize the deflection of light and better realize the long-focus characteristics of the system. More specifically: 1.88 < f34 / f < 16.22.

[0057] 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: 1.1 < f56 / f < 360; the fifth lens and the sixth lens are cemented to form a cemented lens. Satisfying the above range is beneficial to realize the deflection of light and better realize the long-focus characteristics of the system. More specifically: 1.19 < f56 / f < 353.13.

[0058] In some embodiments, the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: -1.25 < f3 / f4 < -0.8. Satisfying the above range, the focal length relationship between the third lens and the fourth lens is reasonably set, which can diverge the light to a certain extent and is beneficial to realize large target surface imaging. More specifically: -1.15 < f3 / f4 < -0.89.

[0059] In some embodiments, the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.25 < f5 / f6 < -0.6. By satisfying the above range, the focal length relationship between the fifth lens and the sixth lens is reasonably set, which can diverge the light rays to a certain extent, which is beneficial to realize large target surface imaging. More specifically: -1.14 < f5 / f6 < -0.66.

[0060] In some embodiments, the optical lens satisfies the following conditional expressions: 19mm < f < 23mm; 30° < FOV < 35°; 11mm < EPD < 14mm; 34mm < TTL < 40mm; 1.5 < Fno < 1.8; 11mm < IH < 14mm; 19° < CRA < 25°; 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 incidence angle at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. By satisfying the above range, the optical lens has one or more advantages such as long focal length, large aperture, high imaging quality, etc. More specifically: 20.68mm < f < 21.39mm; 31.19° < FOV < 34.1°; 12.44mm < EPD < 12.97mm; 34.23mm < TTL < 39.99mm; 1.61 < Fno < 1.71; 12.07mm < IH < 13.47mm; 20.89° < CRA < 23.45°; 3.47mm < BFL < 5.84mm.

[0061] 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.

[0062] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt a spherical lens or an aspherical lens. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the first lens, the second lens, 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.

[0063] In various embodiments of the present application, when the lens adopts an aspheric lens, the shape of each aspheric surface of the optical lens satisfies the following equation: ; wherein z is the distance of the curved surface from the vertex of the curved surface in the direction of the optical axis, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the quadratic surface coefficient, and B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients, respectively.

[0064] The present application is further described in the following embodiments. In various embodiments, the thickness, the radius of curvature, and the material selection of each lens in the optical lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are merely preferred embodiments of the present application, but the embodiments of the present application are not limited to the following embodiments only, and any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present application should be regarded as equivalent replacement modes, and are included in the protection scope of the present application.

[0065] Embodiment 1 Please refer to Figure 1 , which is a structural schematic diagram of an optical lens 100 provided in Embodiment 1 of the present application. The optical lens 100 includes, in order from the object side to the imaging surface along the optical axis, a first lens L1, a stop 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.

[0066] The first lens L1 has a negative focal power, the object side surface S1 thereof is a concave surface, and the image side surface S2 thereof is a convex surface. The second lens L2 has a positive focal power, the object side surface S3 thereof is a convex surface, and the image side surface S4 thereof is a convex surface. The third lens L3 has a negative focal power, the object side surface S5 thereof is a concave surface, and the image side surface S6 thereof is a concave surface. The fourth lens L4 has a positive focal power, the object side surface S6 thereof is a convex surface, and the image side surface S7 thereof is a convex surface. The third lens L3 and the fourth lens L4 form a cemented lens group, and the cemented surface of the image side surface of the third lens L3 and the object side surface of the fourth lens L4 is S6. The fifth lens L5 has a positive focal power, the object side surface S8 thereof is a convex surface, and the image side surface S9 thereof is a convex surface. The sixth lens L6 has a negative focal power, the object side surface S9 thereof is a concave surface, and the image side surface S10 thereof is a concave surface. The fifth lens L5 and the sixth lens L6 form a cemented lens group, and the cemented surface of the image side surface of the fifth lens L5 and the object side surface of the sixth lens L6 is S9. The seventh lens L7 has negative focal power, the object side surface S11 is a concave surface, and the image side surface S12 is a concave surface; The eighth lens L8 has negative focal power, the object side surface S13 is a concave surface, and the image side surface S14 is a convex surface; The object side surface S15 and the image side surface S16 of the filter G1 are both flat surfaces; The object side surface S17 and the image side surface S18 of the protective glass G2 are both flat surfaces; The imaging surface S19 is a flat surface.

[0067] 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.

[0068] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0069] Table 1-1 The surface type parameters of the aspheric lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0070] Table 1-2 In this embodiment, the MTF curve of the optical lens 100 is shown in Figure 2 .

[0071] 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 the embodiment is above 0.4 in the full field of view, and in the range of 0-160 lp / mm, the MTF curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in the case of low frequency and high frequency.

[0072] 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 S4 of the second lens L2 is a concave surface, and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0073] The related parameters of the lenses in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0074] Table 2-1 The surface profile parameters of the aspherical lenses of the optical lens 200 in this embodiment are shown in Table 2-2.

[0075] Table 2-2 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 0.5 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.

[0076] Embodiment 3 Please refer to Figure 5 , which is a structural schematic diagram of the optical lens 300 provided in the embodiment 3 of the present application. Compared with the embodiment 1, the main difference of this embodiment is that the image side surface S14 of the eighth lens L8 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0077] The related parameters of each lens in the optical lens 300 in this embodiment are shown in Table 3-1.

[0078] Table 3-1 The surface profile parameters of the aspherical lenses of the optical lens 300 in this embodiment are shown in Table 3-2.

[0079] Table 3-2 In this embodiment, the MTF curve of the optical lens 300 is shown in Figure 6 From Figure 6 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.

[0080] Embodiment 4 Please refer to Figure 7 , which is a structural schematic diagram of the optical lens 400 provided in the embodiment 4 of the present application. Compared with the embodiment 1, the main difference of this embodiment is that the object side surface S13 of the eighth lens L8 is a convex surface, and the image side surface S14 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

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

[0082] Table 4-1 The surface profile parameters of the aspheric lenses of the optical lens 400 in Embodiment 4 are shown in Table 4-2.

[0083] Table 4-2 In this 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 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.

[0084] Embodiment 5 Please refer to Figure 9 , which is a structural schematic diagram of the optical lens 500 provided in Embodiment 5 of the present application. Compared with Embodiment 1, the main difference is that the image side surface S4 of the second lens L2 is a concave surface; the image side surface S14 of the eighth lens L8 is a concave surface; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0085] The related parameters of the lenses in the optical lens 500 in Embodiment 5 are shown in Table 5-1.

[0086] Table 5-1 The surface profile parameters of the aspheric lenses of the optical lens 500 in Embodiment 5 are shown in Table 5-2.

[0087] Table 5-2 In this embodiment, the MTF curve of the optical lens 500 is shown in Figure 10 From Figure 10 it can be seen that the MTF value of this embodiment is above 0.3 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.

[0088] Embodiment 6 Please refer to Figure 11, which is a structural schematic diagram of the optical lens 600 provided in Embodiment 6 of the present application. Compared with Embodiment 1, the main difference is that the image side surface S4 of the second lens L2 is a concave surface; the object side surface S13 of the eighth lens L8 is a convex surface, and the image side surface S14 is a concave surface; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0089] The related parameters of each lens in the optical lens 600 in Embodiment 6 are shown in Table 6-1.

[0090] Table 6-1 The surface type parameters of the aspherical lens of the optical lens 600 in Embodiment 6 are shown in Table 6-2.

[0091] Table 6-2 In this embodiment, the MTF curve of the optical lens 600 is shown in Figure 12 From Figure 12 , it can be seen that the MTF value of this embodiment is above 0.4 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.

[0092] Please refer to Table 7-1 and Table 7-2, 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.

[0093] Table 7-1 Table 7-2 In summary of the above embodiments, the optical lens provided by the present application adopts eight lenses with specific optical power, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved, so that the lens has one or more advantages such as long focal length, large aperture, high imaging quality, etc.

[0094] 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. Furthermore, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0095] 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 protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An optical lens, comprising eight lenses having optical power, characterized in that: It successively includes from the object side to the imaging surface along the optical axis: A first lens with a negative optical power, whose object side is concave and whose image side is convex; A second lens with a positive optical power, whose object side is convex; A third lens with a negative optical power, whose object side is concave and whose image side is concave; A fourth lens with a positive optical power, whose object side is convex and whose image side is convex; A fifth lens with a positive optical power, whose object side is convex and whose image side is convex; A sixth lens with a negative optical power, whose object side is concave and whose image side is concave; A seventh lens with a negative optical power, whose object side is concave and whose image side is concave; An eighth lens with a negative optical power; Wherein, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 0.75 < f12 / f < 1.

8.

2. The optical lens according to claim 1, wherein: The overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.5 < TTL / f < 1.9; the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.3 < TTL / IH < 3.

4.

3. The optical lens according to claim 1, wherein: The true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 0.9 < IH / EPD < 1.1; the true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 0.5 < IH / f < 0.

7.

4. The optical lens according to claim 1, wherein: The clear aperture semi-diameter d1 of the object side of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 3.5 < d1 / (IH / 2) / Tan(FOV / 2) < 4.5; the combined focal length f12 of the first lens and the second lens and the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: 0.8 < f12 / f1234 < 1.

8.

5. The optical lens according to claim 1, wherein: The focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2 < f1 / f < -1.35; the curvature radius R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: -0.45 < R1 / f < -0.25; the curvature radius R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: -0.7 < R2 / f < -0.

4.

6. The optical lens according to claim 1, wherein: The focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.6 < f2 / f < 1; the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 0.5 < f4 / f < 0.

7.

7. The optical lens according to claim 1, wherein: The focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -0.7 < f3 / f < -0.4; the curvature radius R5 of the object side of the third lens and the effective focal length f of the optical lens satisfy: -4.8 < R5 / f < -2.7; the curvature radius R6 of the image side of the third lens and the effective focal length f of the optical lens satisfy: 0.35 < R6 / f < 0.

55.

8. The optical lens according to claim 1, wherein: The focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -2.7 < f7 / f < -1; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -5.9 < R13 / f < -2.2; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 0.9 < R14 / f < 5.

4.

9. The optical lens according to claim 1, wherein: The combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy: -0.85 < f1234 / f5678 < -0.25; the combined focal length f34 of the third lens and the fourth lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: 0 < f34 / f56 < 9.

5.

10. The optical lens according to claim 1, wherein: The optical lens satisfies at least one of the following conditional expressions. The object-side curvature radius R5 of the third lens and the image-side curvature radius R6 of the third lens satisfy: 1.15 < (R5 - R6) / (R5 + R6) < 1.45; or the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: -5.4 < (R1 + R2) / (R1 - R2) < -3.6; or the object-side curvature radius R7 of the fourth lens and the image-side curvature radius R8 of the fourth lens satisfy: -0.55 < (R7 + R8) / (R7 - R8) < -0.1; or the object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: |(R13 + R14) / (R13 - R14)| < 0.7.

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