Optical lens

Abstract

The invention provides an optical lens, which comprises eight lenses from an object side to an imaging surface along an optical axis: a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with negative focal power, a fifth lens with positive focal power and a sixth lens with negative focal power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the 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 fifth lens has negative focal power, and the object side surface of the fifth lens is a concave surface; the image side surface 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 convex surface; the seventh lens has positive focal power, and the object side surface of the seventh lens is a convex surface near the optical axis; and the object side surface of the eighth lens is a concave surface. According to the optical lens provided by the invention, the imaging quality of the optical lens can be improved, the aberration is reduced, and the imaging quality of the optical lens is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, and particularly to an optical lens. Background Art

[0002] With the development of security technology in recent years, the requirements for the target surface size of surveillance lenses are getting larger and larger. As is well known, the larger the sensor target surface, the better the photosensitive performance and the better the imaging effect. However, at present, most large-target surface lenses on the market generally have problems such as large distortion and poor imaging effect when the surrounding environment is dark. Summary of the Invention

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

[0004] The technical solution adopted by the present invention is as follows: An optical lens, comprising a total of eight lenses, which sequentially include, along the optical axis from the object side to the imaging surface: A first lens with positive optical power, the object side surface of which is convex and the image side surface of which is concave; A second lens with positive optical power, the object side surface of which is convex and the image side surface of which is concave; A third lens with negative optical power, the object side surface of which is concave and the image side surface of which is concave; A fourth lens with positive optical power, the object side surface of which is convex and the image side surface of which is convex; A fifth lens with negative optical power, the object side surface of which is concave and the image side surface of which is convex; A sixth lens with positive optical power, the object side surface of which is concave and the image side surface of which is convex; A seventh lens with positive optical power, the object side surface of which is convex near the optical axis; An eighth lens with negative optical power, the object side surface of which is concave; Wherein, the true image height IH corresponding to the maximum field angle of the optical lens and the F-number Fno of the optical lens satisfy: 8mm < IH / Fno < 9mm.

[0005] Further preferably, 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: -0.5 < f1234 / f5678 < -0.3.

[0006] Further preferably, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.16 < f1 / f2 < 0.2.

[0007] More preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.5 < f1 / f < 1.6.

[0008] More preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 8 < f2 / f < 10.

[0009] More preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -2 < f3 / f < -1.8; the curvature radius R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy: -3.15 < R5 / f < -2.95.

[0010] More preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.3 < f4 / f < 1.5; the curvature radius R7 of the object side surface of the fourth lens and the curvature radius R8 of the image side surface of the fourth lens satisfy: -0.5 < R7 / R8 < -0.3.

[0011] More preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -3 < f5 / f < -1.5; the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.3 < f6 / f < 1.8.

[0012] More preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.5 < f7 / f < 2.8; the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -0.85 < f8 / f < -0.6.

[0013] More preferably, the center thickness CT7 of the seventh lens and the center thickness CT8 of the eighth lens satisfy: 3.2 < CT7 / CT8 < 3.8.

[0014] Compared with the prior art, the optical lens provided by the present invention adopts eight lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power distributions, it can improve the imaging quality of the optical lens, reduce aberration, improve the imaging quality of the optical lens, and endow the lens with one or more advantages such as a large image plane, a large aperture, small distortion, and high definition. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 It is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0016] Figure 2It is the astigmatism curve graph of the optical lens in Embodiment 1 of the present invention.

[0017] Figure 3 It is the F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 4 It is the axial aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0019] Figure 5 It is the lateral chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0020] Figure 6 It is the structural schematic diagram of the optical lens in Embodiment 2 of the present invention.

[0021] Figure 7 It is the astigmatism curve graph of the optical lens in Embodiment 2 of the present invention.

[0022] Figure 8 It is the F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 2 of the present invention.

[0023] Figure 9 It is the axial aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0024] Figure 10 It is the lateral chromatic aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0025] Figure 11 It is the structural schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0026] Figure 12 It is the astigmatism curve graph of the optical lens in Embodiment 3 of the present invention.

[0027] Figure 13 It is the F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 3 of the present invention.

[0028] Figure 14 It is the axial aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0029] Figure 15 It is the lateral chromatic aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0030] Figure 16 It is the structural schematic diagram of the optical lens in Embodiment 4 of the present invention.

[0031] Figure 17 It is the astigmatism curve graph of the optical lens in Embodiment 4 of the present invention.

[0032] Figure 18It is the F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 4 of the present invention.

[0033] Figure 19 It is the axial aberration curve graph of the optical lens in Embodiment 4 of the present invention.

[0034] Figure 20 It is the lateral chromatic aberration curve graph of the optical lens in Embodiment 4 of the present invention.

[0035] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0036] To better understand the present application, each aspect of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application and do not limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] It should be noted that in this specification, the expressions such as first, second, and third are only used to distinguish one feature from another feature and do not represent any limitation on the features. Therefore, without departing from the teachings of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0038] In the drawings, for the sake of clarity, the thickness, size, and shape of the lenses have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are for illustrative purposes only and are not drawn to an exact scale.

[0039] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object to be photographed is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0040] It should also be understood that the terms "comprising", "comprises", "having", "includes" and / or "including", when used in this specification, denote the presence of the stated features, elements and / or components, but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when an expression such as "at least one of..." appears after a list of listed features, it modifies the entire list of listed features, rather than an individual element in the list. In addition, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application". And the term "exemplary" is intended to refer to an example or illustration.

[0041] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning 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.

[0042] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with embodiments.

[0043] The optical lens provided by the embodiment of the present invention has a total of eight lenses, which are, in order from the object side to the imaging surface along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

[0044] In some embodiments, the first lens may have a positive optical power, its object side surface is convex, and its image side surface is concave. The second lens may have a positive optical power, its object side surface is convex, and its image side surface is concave. The third lens may have a negative optical power, its object side surface is concave, and its image side surface is concave. The fourth lens may have a positive optical power, its object side surface is convex, and its image side surface is convex. The fifth lens may have a negative optical power, its object side surface is concave; its image side surface is convex. The sixth lens may have a positive optical power, its object side surface is concave, and its image side surface is convex. The seventh lens may have a positive optical power, its object side surface is convex near the optical axis, and its image side surface may be concave or convex. The eighth lens may have a negative optical power, its object side surface is concave, and its image side surface may be concave or convex.

[0045] In some embodiments, the optical lens may further include an aperture, and the aperture may be located between the object side and the first lens. It can be understood that the aperture is used to limit the amount of incident light to change the brightness of the image.

[0046] In some embodiments, the optical lens may further include a filter, which may be disposed between the eighth lens and the imaging surface. The filter is used to filter out interfering light and prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0047] In some embodiments, the true image height IH corresponding to the maximum field angle of view of the optical lens and the aperture value Fno of the optical lens satisfy: 8mm < IH / Fno < 9mm. Meeting the above conditions can enable the optical lens to have a larger aperture while having a larger imaging surface, ensure that the lens has a larger light flux in a darker environment, and more imaging details can be retained in the dark part, thereby improving the picture quality of the lens in different environments.

[0048] In some embodiments, 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: -0.5 < f1234 / f5678 < -0.3. Meeting the above conditions is conducive to balancing various aberrations of the lens and improving the overall imaging quality by reasonably balancing the focal length relationship between the front and rear lens groups.

[0049] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.16 < f1 / f2 < 0.2. Meeting the above conditions, both the first and second lenses provide positive refractive power. By reasonably matching the focal length relationship between the first and second lenses, they can cooperate with each other to further converge light, which is conducive to the further convergence of incident light and better realizes the balance of the large wide angle and large aperture of the lens.

[0050] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.5 < f1 / f < 1.6. Meeting the above conditions can make the first lens have a larger positive refractive power, improve the light collection ability of the marginal field of view, and is conducive to realizing the large wide angle imaging of the lens.

[0051] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 8 < f2 / f < 10. Meeting the above conditions can make the second lens have an appropriate positive optical power, which is conducive to the smooth transition of the light trend, improves the imaging quality of the optical lens, reduces the system sensitivity at the same time, and improves the manufacturing yield.

[0052] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -2 < f3 / f < -1.8. Meeting the above conditions can make the third lens have a larger negative refractive power, which can diverge the incident light to a greater extent, thereby effectively increasing the height of the light entering the imaging surface and better realizing the large target surface imaging of the lens.

[0053] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy: -3.15 < R5 / f < -2.95. Meeting the above conditions, by reasonably setting the radius of curvature of the object side surface of the third lens, the light can be effectively diverged, which is beneficial to correcting the field curvature, astigmatism and distortion of the optical lens, thus ensuring the imaging quality of the optical lens.

[0054] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.3 < f4 / f < 1.5. Meeting the above conditions can effectively reduce the difficulty of correcting the distortion of the edge field of view, ensure that the lens has a small distortion while achieving a large field of view angle, improve the overall imaging quality, and at the same time reduce the system sensitivity and improve the manufacturing yield.

[0055] In some embodiments, the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: -0.5 < R7 / R8 < -0.3. Meeting the above conditions, by setting the biconvex surface type of the fourth lens, it is beneficial to better converge the light, shorten the distance of the light reaching the next lens, and is beneficial to reducing the total length of the optical lens.

[0056] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -3 < f5 / f < -1.5. Meeting the above conditions is beneficial to diverging the light of the central field of view to a certain extent, and at the same time combining the bending of the edge field of view to reduce the exit angle of the light in the edge field of view and improve the relative illumination of the edge field of view.

[0057] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.3 < f6 / f < 1.8. Meeting the above conditions is beneficial to correcting the field curvature and distortion of the optical lens and improving the imaging quality of the optical lens.

[0058] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.5 < f7 / f < 2.8. Meeting the above conditions is beneficial to balancing the astigmatism and field curvature of the optical lens and improving the imaging quality of the optical lens.

[0059] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -0.85 < f8 / f < -0.6. Meeting the above conditions is beneficial to further diverging the incident light, making the peripheral light and the central light turn up and reach a higher imaging position, better realizing the large target surface imaging of the lens and improving the imaging quality.

[0060] In some embodiments, the central thickness CT7 of the seventh lens and the central thickness CT8 of the eighth lens satisfy: 3.2 < CT7 / CT8 < 3.8. Meeting the above conditions, by reasonably setting the relationship between the central thicknesses of the seventh and eighth lenses, it is ensured that while meeting the processing requirements, the assembly sensitivity of the optical lens is reduced, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0061] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.3 < TTL / f < 1.38. Meeting the above conditions can effectively limit the length of the lens, which is beneficial to the miniaturization of the optical lens.

[0062] In some embodiments, 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: 1.9 < IH / f < 2.05. Meeting the above conditions is beneficial to the large image plane characteristic of the optical lens, enabling the lens to match the large-size photosensitive chip of the camera module, and thus improving the imaging quality of the optical lens.

[0063] In some embodiments, the object-side curvature radius R5 of the third lens and the image-side curvature radius R6 of the third lens satisfy: -1.4 < R5 / R6 < -1.3. Meeting the above conditions, by reasonably setting the double concave shape of the third lens, it is beneficial to correct the field curvature, astigmatism and distortion of the optical lens, thereby ensuring the imaging quality of the optical lens.

[0064] In some embodiments, the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 1 < f1234 / f < 1.2. Meeting the above conditions, by reasonably setting the focal length relationship of the first four lenses, the object plane light with a wide field angle can be converged into the lens, better correcting the edge distortion of the lens without generating large aberrations, and better achieving the high-quality imaging of the lens.

[0065] In some embodiments, the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: -3.3 < f5678 / f < -2. Meeting the above conditions, by reasonably setting the focal length relationship of the last four lenses, the light entering the system can be diverged to a certain extent, which is beneficial to increasing the height of the light entering the image plane, achieving the large target plane imaging of the lens, and at the same time being beneficial to balancing the distortion and astigmatism generated by the front-end lens of the optical lens and improving the imaging quality of the optical lens.

[0066] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis and the total optical length TTL of the optical lens satisfy: 0.52 < ∑CT / TTL < 0.6. Satisfying the above conditions can effectively compress the total length of the optical lens, and is also beneficial to the structural design and production process of the optical lens.

[0067] In some embodiments, the optical lens satisfies the conditional formula: 8.5 mm < f < 9.5 mm, 85° < FOV < 95°, 11.5 mm < TTL < 12.5 mm, 1.9 < Fno < 2.1, 16.5 mm < IH < 18 mm; where f represents the effective focal length of the optical lens, FOV represents the maximum field angle of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, and IH represents the true image height corresponding to the maximum field angle of the optical lens. Satisfying the above conditions indicates that the lens has a large field angle and can achieve a large shooting range; it indicates that the lens has a large aperture value and can achieve high-definition imaging even in a relatively dark environment; it indicates that the lens has a large target surface and can match an imaging chip with a large target surface to achieve high-definition imaging. Moreover, with the increase of the target surface, the pixel distribution can be sparser, and even in a relatively dark environment, noise can be effectively reduced, the dynamic range will be wider, and more imaging details can be retained in the dark part, so as to present a clearer shooting effect.

[0068] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The optical lens provided by the present invention can adopt an all-plastic lens structure, which not only enables the lens to have excellent imaging performance, but also makes the structure of the lens relatively compact, and can better achieve the balance of miniaturization and high image quality of the lens.

[0069] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving the miniaturization of the lens. More specifically, 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 of the present invention can all adopt aspherical lenses, which can effectively reduce the aberration of the optical lens, thereby reducing the number of lenses and the size of the lenses, and better achieving the miniaturization of the lens.

[0070] In each embodiment of the present invention, when the lens adopts an aspherical lens, the surface shape of the aspherical lens satisfies the following equation: ; Among them, z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, k is the conic coefficient, and A 2i is the aspheric surface type coefficient of the 2i-th order.

[0071] The present invention will be further described below with multiple embodiments. In each embodiment, the thickness, curvature radius, and material selection of each lens in the optical lens are somewhat different. For specific differences, refer to the parameter tables of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any other changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention shall be regarded as equivalent replacement methods and are all included in the protection scope of the present invention.

[0072] Embodiment 1 Please refer to Figure 1 , which shows a schematic structural diagram of an optical lens 100 provided in Embodiment 1 of the present invention. The optical lens sequentially includes, along the optical axis from the object side to the imaging surface S19: an aperture stop ST, a first lens L1, 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, and a filter G1.

[0073] Among them, the first lens L1 has a positive optical power, its object side surface S1 is a convex surface, and its image side surface S2 is a concave surface; The second lens L2 has a positive optical power, its object side surface S3 is a convex surface, and its image side surface S4 is a concave surface; The third lens L3 has a negative optical power, its object side surface S5 is a concave surface, and its image side surface S6 is a concave surface; The fourth lens L4 has a positive optical power, its object side surface S7 is a convex surface, and its image side surface S8 is a convex surface; The fifth lens L5 has a negative optical power, its object side surface S9 is a concave surface, and its image side surface S10 is a convex surface; The sixth lens L6 has a positive optical power, its object side surface S11 is a concave surface, and its image side surface S12 is a convex surface; The seventh lens L7 has a positive optical power, its object side surface S13 is a convex surface near the optical axis, and its image side surface S14 is a convex surface; The eighth lens L8 has a negative optical power, its object side surface S15 is a concave surface, and its image side surface S16 is a concave surface near the optical axis; Both the object side surface S17 and the image side surface S18 of the filter G1 are flat surfaces; The imaging surface S19 is a flat surface.

[0074] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are all plastic aspherical lenses.

[0075] The relevant parameters of each lens in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0076] Table 1-1 The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0077] Table 1-2 In this embodiment, the astigmatism curve graph, F-Tan(Theta) distortion curve graph, axial aberration curve graph, and lateral chromatic aberration curve graph of the optical lens 100 are respectively as Figure 2 , Figure 3 , Figure 4 , Figure 5 shown.

[0078] Figure 2 shows the astigmatism curve graph of the optical lens 100 in this embodiment, which represents the astigmatism of light rays in the meridional image plane and the sagittal image plane. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 100 can better correct astigmatism.

[0079] Figure 3 shows the F-Tan(Theta) distortion curve graph of the optical lens 100 in this embodiment, which represents the distortion at different field angles on the imaging plane. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the distortion value is controlled within ±1%, indicating that the optical lens 100 can better correct distortion.

[0080] Figure 4 shows the axial aberration curve graph of the optical lens 100 in this embodiment, which represents the axial aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the offset of the axial aberration is controlled within ±0.03 mm, indicating that the optical lens 100 can better correct axial aberration.

[0081] Figure 5Fig. 0 shows the lateral color aberration curve of the optical lens 100 in this embodiment, which represents the color aberration of each wavelength relative to the central wavelength (0.555 μm) at different image heights on the imaging plane. The horizontal axis represents the lateral color aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the lateral color aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 100 can correct color aberration well.

[0082] Embodiment 2 Please refer to Figure 6 , which shows the schematic structural diagram of the optical lens 200 provided in Embodiment 2 of the present invention. Compared with Embodiment 1, the main differences are as follows: The image side surface S16 of the eighth lens L8 is a convex surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0083] The relevant parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0084] Table 2-1 The surface type parameters of the aspherical lenses of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0085] Table 2-2 In this embodiment, the astigmatism curve, F-Tan(Theta) distortion curve, axial aberration curve, and lateral color aberration curve of the optical lens 200 are respectively as Figure 7 , Figure 8 , Figure 9 , Figure 10 shown.

[0086] From Figure 7 it can be seen that the astigmatism between the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 200 can correct astigmatism well.

[0087] From Figure 8 it can be seen that the distortion value is controlled within ±1%, indicating that the optical lens 200 can correct distortion well.

[0088] From Figure 9 it can be seen that the offset of the axial aberration is controlled within ±0.03 mm, indicating that the optical lens 200 can correct axial aberration well.

[0089] From Figure 10 it can be seen that the lateral color aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 200 can correct color aberration well.

[0090] Example 3 Please refer to Figure 11 , which shows a schematic structural diagram of the optical lens 300 provided in Embodiment 3 of the present invention. Compared with Embodiment 1, the main differences are as follows: the image side S14 of the seventh lens L7 is concave near the optical axis; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0091] The relevant parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0092] Table 3-1 The surface type parameters of the aspherical lenses of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0093] Table 3-2 In this embodiment, the astigmatism curve graph, F-Tan(Theta) distortion curve graph, axial aberration curve graph, and lateral chromatic aberration curve graph of the optical lens 300 are respectively as Figure 12 , Figure 13 , Figure 14 , Figure 15 shown.

[0094] From Figure 12 it can be seen that the astigmatism between the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 300 can better correct astigmatism.

[0095] From Figure 13 it can be seen that the distortion value is controlled within ±1%, indicating that the optical lens 300 can better correct distortion.

[0096] From Figure 14 it can be seen that the offset of the axial aberration is controlled within ±0.02 mm, indicating that the optical lens 300 can better correct axial aberration.

[0097] From Figure 15 it can be seen that the lateral chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 300 can better correct chromatic aberration.

[0098] Example 4 Please refer to Figure 16 , which shows a schematic structural diagram of the optical lens 400 provided in Embodiment 4 of the present invention. Compared with Embodiment 1, the main differences are as follows: the image side S14 of the seventh lens L7 is concave near the optical axis; the image side S16 of the eighth lens L8 is convex; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0099] The relevant parameters of each lens in the optical lens 400 in Embodiment 4 are shown in Table 4-1.

[0100] Table 4-1 The surface type parameters of the aspherical lens of the optical lens 400 in Embodiment 4 are shown in Table 4-2.

[0101] Table 4-2 In this embodiment, the astigmatism curve graph, F-Tan(Theta) distortion curve graph, axial aberration curve graph, and lateral chromatic aberration curve graph of the optical lens 400 are respectively as Figure 17 , Figure 18 , Figure 19 , Figure 20 shown.

[0102] From Figure 17 , it can be seen that the astigmatism between the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 400 can better correct astigmatism.

[0103] From Figure 18 , it can be seen that the distortion value is controlled within ±1%, indicating that the optical lens 400 can better correct distortion.

[0104] From Figure 19 , it can be seen that the offset of the axial aberration is controlled within ±0.02 mm, indicating that the optical lens 400 can better correct axial aberration.

[0105] From Figure 20 , it can be seen that the lateral chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 400 can better correct chromatic aberration.

[0106] Please refer to Table 5 for the optical characteristics corresponding to the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, true image height IH corresponding to the maximum field angle, chief ray angle of incidence CRA at the maximum image height, maximum field angle FOV, and the values corresponding to each conditional formula in each embodiment.

[0107] Table 5 Based on the above embodiments, the optical lens provided by the present invention has at least the following advantages: (1) Through specific surface shape settings and reasonable optical power distribution, it has a large viewing angle and can achieve a large shooting range; at the same time, it has a large aperture value, enabling high-definition imaging even in a relatively dark environment.

[0108] (2) The lens has a large target surface, which can match an imaging chip with a large target surface to achieve high-definition imaging. Moreover, with the increase of the target surface, the pixel distribution can be sparser, effectively reducing noise even in a relatively dark environment, and the dynamic range will be wider, retaining more imaging details in the dark part, thus presenting a clearer shooting effect; at the same time, it can also reasonably correct the overall aberration of the optical lens, making the optical lens have small distortion and high clarity, and improving the imaging quality of the optical lens.

[0109] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. 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 invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0110] The above embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. An optical lens, comprising eight lenses, characterized in that: It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with a positive optical power, whose object side is convex and whose image side is concave; A second lens with a positive optical power, whose object side is convex and whose image side is concave; 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 negative optical power, whose object side is concave; whose image side is convex; A sixth lens with a positive optical power, whose object side is concave and whose image side is convex; A seventh lens with a positive optical power, whose object side is convex near the optical axis; An eighth lens with a negative optical power, whose object side is concave; Wherein, the true image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 8mm < IH / Fno < 9mm.

2. 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: -0.5 < f1234 / f5678 < -0.

3.

3. The optical lens according to claim 1, wherein: The focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.16 < f1 / f2 < 0.

2.

4. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.5 < f1 / f < 1.

6.

5. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 8 < f2 / f < 10.

6. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -2 < f3 / f < -1.8; the curvature radius R5 of the object side of the third lens and the effective focal length f of the optical lens satisfy: -3.15 < R5 / f < -2.

95.

7. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.3 < f4 / f < 1.5; the curvature radius R7 of the object side of the fourth lens and the curvature radius R8 of the image side of the fourth lens satisfy: -0.5 < R7 / R8 < -0.

3.

8. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -3 < f5 / f < -1.5; the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.3 < f6 / f < 1.

8.

9. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.5 < f7 / f < 2.8; the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -0.85 < f8 / f < -0.

6.

10. The optical lens according to claim 1, wherein: The central thickness CT7 of the seventh lens and the central thickness CT8 of the eighth lens satisfy: 3.2 < CT7 / CT8 < 3.8.

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