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 image side surface of the second lens is a convex surface; the third lens has negative focal power, the object side surface of the third lens near the optical axis is a convex surface, and the image side surface of the third lens is a concave surface; the fourth lens has focal power, and the object side surface of the fourth lens is a convex surface; the fifth lens has positive focal power; the sixth lens has positive focal power, and the image side surface of the sixth lens is a convex surface; the seventh lens has positive focal power, and the image side surface of the seventh lens is a convex surface; and the object side surface of the eighth lens is a concave surface, and the image side surface of the eighth lens is a concave surface near the optical axis. 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 requirement for the target surface size of surveillance lenses is 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, most of the large target surface lenses on the market currently generally have problems of large distortion and poor imaging effect when the surrounding environment is relatively dark. Summary of the Invention

[0003] In view of the above problems, the object 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 successively include from the object side to the imaging surface along the optical axis: A first lens with positive optical power, the object side surface thereof is convex, and the image side surface thereof is concave; A second lens with positive optical power, the image side surface thereof is convex; A third lens with negative optical power, the object side surface thereof is convex near the optical axis, and the image side surface thereof is concave; A fourth lens with optical power, the object side surface thereof is convex; A fifth lens with positive optical power; A sixth lens with positive optical power, the image side surface thereof is convex; A seventh lens with positive optical power, the image side surface thereof is convex; An eighth lens with negative optical power, the object side surface thereof is concave, and the image side surface thereof is concave near the optical axis; Wherein, the true image height IH corresponding to the maximum field of view angle of the optical lens and the aperture value Fno of the optical lens satisfy: 9.5mm < IH / Fno < 11mm.

[0005] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.2 < f1 / f < 1.8; the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.5 < f1 / f2 < 1.

[0006] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.3 < f2 / f < 2.5; the curvature radius R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: -1.5 < R4 / f < -0.6.

[0007] More preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.8 < f3 / f < -1; the curvature radius R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy: 2.8 < R5 / f < 4.5.

[0008] More preferably, the curvature radius R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 1.2 < R7 / f < 2; the curvature radius R4 of the image side surface of the second lens and the curvature radius R5 of the object side surface of the third lens satisfy: -0.35 < R4 / R5 < -0.2.

[0009] More preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.2 < f5 / f < 8.

[0010] More preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 2.2 < f6 / f < 3.5; the curvature radius R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -3.5 < R12 / f < -1.3.

[0011] More preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.2 < f7 / f < 2; the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -0.6 < f8 / f < -0.35.

[0012] More preferably, 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: 1.1 < f1234 / f < 1.8.

[0013] More preferably, the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -4 < f7 / f8 < -3; the central thickness CT7 of the seventh lens and the central thickness CT8 of the eighth lens satisfy: 0.33 < CT7 / CT8 < 0.8.

[0014] Compared with the prior art, the optical lens provided by the present invention uses eight lenses with specific optical powers. 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, the imaging quality of the optical lens can be improved, and the lens has one or more advantages such as a large image plane, a large aperture, a 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 obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein: Figure 1 This is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0030] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0031] To better understand the present application, various aspects 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.

[0032] It should be noted that in this specification, the expressions such as first, second, third, etc. 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.

[0033] In the drawings, for ease of illustration, the thickness, size, and shape of the lens 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 only examples and are not drawn to an exact scale.

[0034] In this document, 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 being 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.

[0035] It should also be understood that the terms "comprise", "comprising", "have", "include", and / or "including", when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. 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 the 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.

[0036] 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 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.

[0037] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following will describe the present application in detail with reference to the drawings and in combination with the embodiments.

[0038] 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.

[0039] In some embodiments, the first lens may have a positive optical power, its object side is a convex surface, and its image side is a concave surface. The second lens may have a positive optical power, its object side may be a concave surface or a convex surface, and its image side is a convex surface. The third lens may have a negative optical power, its object side is a convex surface near the optical axis, and its image side is a concave surface. The fourth lens may have a positive optical power or a negative optical power, its object side is a convex surface, and its image side may be a concave surface or a convex surface. The fifth lens may have a positive optical power, its object side may be a concave surface or a convex surface, and its image side may be a concave surface or a convex surface. The sixth lens may have a positive optical power, its object side may be a concave surface or a convex surface, and its image side is a convex surface. The seventh lens may have a positive optical power, its object side may be a concave surface or a convex surface, and its image side is a convex surface. The eighth lens may have a negative optical power, its object side is a concave surface, and its image side is a concave surface near the optical axis.

[0040] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the object side and the first lens. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the image.

[0041] In some embodiments, the optical lens may further include a filter, and the filter may be disposed between the eighth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0042] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the aperture value Fno of the optical lens satisfy: 9.5mm < IH / Fno < 11mm. Satisfying the above conditions can enable the lens to have a larger aperture while having a larger imaging target surface, ensuring that the lens has a larger light flux in a darker environment, thereby improving the picture quality of the lens in different environments.

[0043] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.2 < f1 / f < 1.8. Satisfying the above conditions can enable the first lens to have a larger positive refractive power, improving the ability to collect marginal field light rays while facilitating large-angle wide-angle imaging of the lens.

[0044] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.5 < f1 / f2 < 1. Meeting the above conditions, both the first and second lenses provide positive refractive power. By reasonably matching the spacing relationship between the first and second lenses, they can cooperate with each other to further converge light, which is beneficial to the further convergence of incident light and better realizes the balance of a large wide-angle and a large aperture of the lens.

[0045] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.3 < f2 / f < 2.5; the image-side curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: -1.5 < R4 / f < -0.6. Meeting the above conditions can make the second lens have an appropriate positive optical power, which is beneficial to the smooth transition of the light path, improves the imaging quality of the optical lens, and at the same time can reduce the system sensitivity and improve the manufacturing yield.

[0046] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.8 < f3 / f < -1; the object-side curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: 2.8 < R5 / f < 4.5. Meeting the above conditions can make the third lens have a large negative refractive power, which can diverge the incident light to a large extent, thereby effectively increasing the height of the light entering the imaging surface and better realizing the large target surface imaging of the lens.

[0047] In some embodiments, the object-side curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.2 < R7 / f < 2. Meeting the above conditions, by reasonably setting the object-side curvature radius of the fourth lens, the incident light can be smoothly transitioned, the difficulty of correcting the marginal field distortion can be reduced, and the overall imaging quality can be improved.

[0048] In some embodiments, the image-side curvature radius R4 of the second lens and the object-side curvature radius R5 of the third lens satisfy: -0.35 < R4 / R5 < -0.2. Meeting the above conditions, by reasonably setting the curvature radii of the adjacent surfaces of the second and third lenses, it is beneficial to appropriately diverge the light incident after passing through the second lens, making the light path smoothly transition and improving the imaging quality of the optical lens.

[0049] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.2 < f5 / f < 8. Meeting the above conditions is beneficial to diverging the light in the central field of view to a certain extent, and at the same time, combined with the curvature of the marginal field of view, reducing the exit angle of the light in the marginal field of view and improving the relative illumination of the marginal field of view.

[0050] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 2.2 < f6 / f < 3.5. 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.

[0051] In some embodiments, the image-side curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: -3.5 < R12 / f < -1.3. Meeting the above conditions is beneficial to better achieving the convergence of light, shortening the distance for light to reach the next lens, and is beneficial to reducing the total length of the optical lens.

[0052] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.2 < f7 / f < 2. 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.

[0053] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -0.6 < f8 / f < -0.35. Meeting the above conditions is beneficial to further diverging the incident light, causing the peripheral light and the central light to turn upwards, reaching a higher imaging position, better achieving the large target surface imaging of the lens, and improving the imaging quality.

[0054] 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: 1.1 < f1234 / f < 1.8. Meeting the above conditions is beneficial to the convergence of light, enabling the light entering the system from the front end to smoothly enter the rear optical system, making the overall optical path more gentle, optimizing the aberration, and improving the resolution.

[0055] In some embodiments, the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -4 < f7 / f8 < -3; the central thickness CT7 of the seventh lens and the central thickness CT8 of the eighth lens satisfy: 0.33 < CT7 / CT8 < 0.8. Meeting the above conditions, by reasonably setting the relationship between the focal lengths and the central thicknesses of the seventh and eighth lenses, while ensuring good processability of the lenses, it is beneficial to diverge the light in the central field of view to a certain extent, and at the same time, combined with the bending of the marginal field of view of the eighth lens, reduce the exit angle of the marginal field of view light and improve the relative illumination of the marginal field of view.

[0056] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.1 < BFL / f < 0.15; the back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0.08 < BFL / TTL < 0.12. Meeting the above conditions can make the lens have an appropriate back focal length, ensure the compatibility between the lens and the fuselage, and make the structure of the lens more compact.

[0057] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.62 < TTL / IH < 0.7. Meeting the above conditions can better achieve the miniaturization of the lens, while ensuring that the lens has a larger image plane and can match a larger-sized imaging chip to achieve high-definition imaging.

[0058] 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: -0.7 < f1234 / f5678 < 0.01. Meeting the above conditions, by reasonably setting the focal length relationship between the front and rear lens groups, it helps the smooth transition of light, expands the field of view angle of the optical imaging lens, reduces the difficulty of correcting distortion and chromatic aberration of the rear lens, and improves the image quality of the optical lens.

[0059] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis respectively and the total optical length TTL of the optical lens satisfy: 0.55 < ∑CT / TTL < 0.65. Meeting the above conditions can effectively compress the total length of the optical lens, while being beneficial to the structural design and production process of the optical lens.

[0060] In some embodiments, the optical lens satisfies the conditional formula: 8mm < f < 9mm, 80° < FOV < 90°, 10.5mm < TTL < 11.5mm, 1.5 < Fno < 1.7, 15.5mm < IH < 17.5mm; where f represents the effective focal length of the optical lens, FOV represents the maximum field of view 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 of view angle of the optical lens. Meeting the above conditions indicates that the lens has a large field of view 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, effectively reducing noise even in a relatively dark environment, and 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.

[0061] 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 between the miniaturization of the lens and high image 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 spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the first lens, the second lens, the 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 realizing the miniaturization of the lens.

[0063] 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: ; where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, 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 conic coefficient, and A 2i is the aspherical surface coefficient of the 2i-th order.

[0064] The present invention will be further described in multiple embodiments below. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are somewhat different. For specific differences, please refer to the parameter tables of each embodiment. The following embodiments are only the preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0065] Embodiment 1 Please refer to Figure 1 , which shows a schematic structural diagram of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens sequentially includes, from the object side to the imaging surface S19 along the optical axis: a diaphragm 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.

[0066] Among them, the first lens L1 has a positive optical power, its object side S1 is convex, and its image side S2 is concave; The second lens L2 has a positive optical power, its object side S3 is convex, and its image side S4 is convex; The third lens L3 has a negative optical power, its object side S5 is convex near the optical axis, and its image side S6 is concave; The fourth lens L4 has a positive optical power, its object side S7 is convex, and its image side S8 is concave; The fifth lens L5 has a positive optical power, its object side S9 is convex, and its image side S10 is concave near the optical axis; The sixth lens L6 has a positive optical power, its object side S11 is convex near the optical axis, and its image side S12 is convex; The seventh lens L7 has a positive optical power, its object side S13 is concave, and its image side S14 is convex; The eighth lens L8 has a negative optical power, its object side S15 is concave, and its image side S16 is concave near the optical axis; Both the object side S17 and the image side S18 of the filter G1 are flat; The imaging surface S19 is flat.

[0067] 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 all adopt plastic aspherical lenses.

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

[0069] 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.

[0070] 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.

[0071] Figure 2The astigmatism curve graph of the optical lens 100 in this embodiment is shown, 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 ±0.15 mm, indicating that the optical lens 100 can correct astigmatism well.

[0072] Figure 3 The F-Tan(Theta) distortion curve graph of the optical lens 100 in this embodiment is shown, which represents the distortion of 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 ±2.5%, indicating that the optical lens 100 can correct distortion well.

[0073] Figure 4 The axial aberration curve graph of the optical lens 100 in this embodiment is shown, 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 ±0.1 mm, indicating that the optical lens 100 can correct axial aberration well.

[0074] Figure 5 The lateral chromatic aberration curve graph of the optical lens 100 in this embodiment is shown, which represents the chromatic 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 chromatic 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 chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 100 can correct chromatic aberration well.

[0075] Embodiment 2 Please refer to Figure 6 , which shows the structural schematic diagram of the optical lens 200 provided in Embodiment 2 of the present invention. Compared with Embodiment 1, the main differences are: the object side surface S3 of the second lens L2 is concave near the optical axis; the image side surface S8 of the fourth lens L4 is convex; the object side surface S9 of the fifth lens L5 is concave; the image side surface S10 of the fifth lens L5 is convex; the object side surface S11 of the sixth lens L6 is concave; the object side surface S13 of the seventh lens L7 is convex near the optical axis; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0076] The relevant parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0077] Table 2-1 The surface parameters of the aspherical lens of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0078] Table 2-2 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 200 are respectively as Figure 7 , Figure 8 , Figure 9 , Figure 10 shown.

[0079] From Figure 7 , it can be seen that the astigmatism between the meridional image plane and the sagittal image plane is controlled within ±0.15 mm, indicating that the optical lens 200 can correct astigmatism well.

[0080] From Figure 8 , it can be seen that the distortion value is controlled within ±3%, indicating that the optical lens 200 can correct distortion well.

[0081] From Figure 9 , it can be seen that the offset of the axial aberration is controlled within ±0.1 mm, indicating that the optical lens 200 can correct axial aberration well.

[0082] From Figure 10 [[ID=�5]], 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 200 can correct chromatic aberration well.

[0083] Embodiment 3 Please refer to Figure 11 , which shows the structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present invention. Compared with Embodiment 1, the main differences are: the fourth lens L4 has a negative optical power; the object side surface S3 of the second lens L2 is concave near the optical axis; the object side surface S11 of the sixth lens L6 is concave; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0084] The relevant parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0085] Table 3-1 The surface parameters of the aspherical lens of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0086] 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.

[0087] 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 correct astigmatism well.

[0088] From Figure 13 , it can be seen that the distortion value is controlled within ±2.5%, indicating that the optical lens 300 can correct distortion well.

[0089] From Figure 14 , it can be seen that the offset of the axial aberration is controlled within ±0.1 mm, indicating that the optical lens 300 can correct axial aberration well.

[0090] 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 correct chromatic aberration well.

[0091] Please refer to Table 4 for the optical characteristics corresponding to the above embodiments, including the effective focal length f, total optical length TTL, f-number Fno, true image height IH corresponding to the maximum field of view angle, chief ray angle of incidence CRA at the maximum image height, maximum field of view angle FOV, and the values corresponding to each conditional formula in each embodiment.

[0092] Table 4 In summary of 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 field of view angle and can achieve a large shooting range; at the same time, it has a large f-number, and high-definition imaging can be achieved even in a relatively dark environment.

[0093] (2) The lens has a large target surface, can match an imaging chip with a large target surface to achieve high-definition imaging, and 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, and more imaging details can be retained in the dark part, so as to present 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.

[0094] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. mean 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 representations 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.

[0095] The above-described embodiments merely represent several implementation manners of the present invention. The descriptions are relatively specific and detailed, but should not be construed as a limitation on the scope of the patent for 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 for the present invention shall be subject to the appended claims.

Claims

1. An optical lens, with a total of eight lenses, characterized in that, It sequentially includes, from the object side to the imaging surface along the optical axis: A first lens with positive optical power, whose object side is convex and whose image side is concave; A second lens with positive optical power, whose image side is convex; A third lens with negative optical power, whose object side is convex near the optical axis and whose image side is concave; A fourth lens with optical power, whose object side is convex; A fifth lens with positive optical power; A sixth lens with positive optical power, whose image side is convex; A seventh lens with positive optical power, whose image side is convex; An eighth lens with negative optical power, whose object side is concave and whose image side is concave near the optical axis; Wherein, the true image height IH corresponding to the maximum field of view angle of the optical lens and the F - number Fno of the optical lens satisfy: 9.5mm < IH / Fno < 11mm.

2. 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: 1.2 < f1 / f < 1.8; The focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.5 < f1 / f2 < 1.

3. 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: 1.3 < f2 / f < 2.5; The radius of curvature R4 of the image side of the second lens and the effective focal length f of the optical lens satisfy: - 1.5 < R4 / f < - 0.

6.

4. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: - 1.8 < f3 / f < - 1; The radius of curvature R5 of the object side of the third lens and the effective focal length f of the optical lens satisfy: 2.8 < R5 / f < 4.

5.

5. The optical lens according to claim 1, characterized in that, The radius of curvature R7 of the object side of the fourth lens and the effective focal length f of the optical lens satisfy: 1.2 < R7 / f < 2; The radius of curvature R4 of the image side of the second lens and the radius of curvature R5 of the object side of the third lens satisfy: - 0.35 < R4 / R5 < - 0.

2.

6. 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: 1.2 < f5 / f < 8.

7. The optical lens according to claim 1, wherein The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 2.2 < f6 / f < 3.5; The radius of curvature R12 of the image side of the sixth lens and the effective focal length f of the optical lens satisfy: - 3.5 < R12 / f < - 1.

3.

8. 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: 1.2 < f7 / f < 2; The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: - 0.6 < f8 / f < - 0.

35.

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 effective focal length f of the optical lens satisfy: 1.1 < f1234 / f < 1.

8.

10. The optical lens according to claim 1, characterized in that, The focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: - 4 < f7 / f8 < - 3; The central thickness CT7 of the seventh lens and the central thickness CT8 of the eighth lens satisfy: 0.33 < CT7 / CT8 < 0.8.

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