Optical lens

Abstract

The invention provides an optical lens, which consists of eight lenses, and sequentially comprises a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power and a fourth lens with negative focal power from an object side to an imaging surface along an optical axis, the image side surface of the second lens is a concave surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens near the optical axis is a concave surface; the fourth lens has negative focal power, and the object side surface of the fourth lens is a concave surface; the fifth lens has positive focal power, and the object side surface of the fifth lens is a convex surface near the optical axis; 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 object side surface of the seventh lens is a concave surface, 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. 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 technologies in recent years, the requirements for the target surface size of surveillance lenses are getting higher and higher. 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 current products on the market cannot meet the requirements of high pixels and large pixel points at the same time. Insufficient photosensitivity when taking pictures in a relatively dark environment will bring a lot of noise to the image quality, resulting in a decline in image quality and unclear imaging. 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:

[0005] An optical lens is composed of eight lenses, and successively includes, along the optical axis from the object side to the imaging surface:

[0006] A first lens with positive optical power, whose object side is convex;

[0007] A second lens with negative optical power, whose image side is concave;

[0008] A third lens with positive optical power, whose object side is convex and whose image side is concave near the optical axis;

[0009] A fourth lens with negative optical power, whose object side is concave;

[0010] A fifth lens with positive optical power, whose object side is convex near the optical axis; and whose image side is convex;

[0011] A sixth lens with negative optical power, whose object side is concave and whose image side is convex;

[0012] A seventh lens with negative optical power, whose object side is concave and whose image side is convex;

[0013] An eighth lens with negative optical power, whose object side is concave;

[0014] 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: 9.3mm < IH / Fno < 9.7mm.

[0015] Further preferably, the overall 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: 0.88 < TTL / IH < 0.92.

[0016] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 0.6 < f1 / f < 0.8.

[0017] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -1.35 < f2 / f < -0.9.

[0018] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2 < f3 / f < 3; the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: 0.4 < R5 / R6 < 0.6.

[0019] Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -4 < f4 / f < -2; the curvature radius R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -2.5 < R7 / f < -1.5.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.65 < f5 / f < 1.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -14 < f6 / f < -2.5; the curvature radius R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -1.4 < R12 / f < -0.8.

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -38 < f7 / f < -2; the curvature radius R14 of the image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -2.2 < R14 / f < -1.

[0023] Further preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -0.8 < f8 / f < -0.5.

[0024] Further preferably, the combined focal length f56 of the fifth lens and the sixth lens and the combined focal length f78 of the seventh lens and the eighth lens satisfy: -2.1 < f56 / f78 < -1.7.

[0025] Compared with the prior art, the optical lens provided by the present invention adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, can improve the imaging quality of the optical lens, reduce aberration, improve the imaging quality of the optical lens, and make the lens have one or more advantages such as a large target surface, a large aperture, and high pixels. Brief Description of the Drawings

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

[0027] Figure 1 It is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 2 It is a field curvature curve graph of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 3 It is an f~tan(θ) distortion curve graph of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 4 It is an axial chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 5 It is a lateral chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 6 It is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 7 It is a field curvature curve graph of the optical lens in Embodiment 2 of the present invention.

[0034] Figure 8 It is an f~tan(θ) distortion curve graph of the optical lens in Embodiment 2 of the present invention.

[0035] Figure 9 It is an axial chromatic aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0036] Figure 10 It is a lateral chromatic aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0037] Figure 11 It is a schematic structural diagram of the optical lens in Embodiment 3 of the present invention.

[0038] Figure 12 It is a field curvature curve graph of the optical lens in Embodiment 3 of the present invention.

[0039] Figure 13 It is an f~tan(θ) distortion curve graph of the optical lens in Embodiment 3 of the present invention.

[0040] Figure 14 It is an axial chromatic aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0041] Figure 15It is the lateral chromatic aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0042] Figure 16 It is the structural schematic diagram of the optical lens in Embodiment 4 of the present invention.

[0043] Figure 17 It is the field curvature curve graph of the optical lens in Embodiment 4 of the present invention.

[0044] Figure 18 It is the f~tan(θ) distortion curve graph of the optical lens in Embodiment 4 of the present invention.

[0045] Figure 19 It is the axial chromatic aberration curve graph of the optical lens in Embodiment 4 of the present invention.

[0046] Figure 20 It is the lateral chromatic aberration curve graph of the optical lens in Embodiment 4 of the present invention.

[0047] Figure 21 It is the structural schematic diagram of the optical lens in Embodiment 5 of the present invention.

[0048] Figure 22 It is the field curvature curve graph of the optical lens in Embodiment 5 of the present invention.

[0049] Figure 23 It is the f~tan(θ) distortion curve graph of the optical lens in Embodiment 5 of the present invention.

[0050] Figure 24 It is the axial chromatic aberration curve graph of the optical lens in Embodiment 5 of the present invention.

[0051] Figure 25 It is the lateral chromatic aberration curve graph of the optical lens in Embodiment 5 of the present invention.

[0052] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0053] To better understand the present application, more detailed descriptions will be made on various aspects of the present application 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.

[0054] 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 feature. 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.

[0055] In the drawings, for ease of explanation, the thickness, size, and shape of the lenses have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are presented by way of example. That is, the spherical or aspherical shapes are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not drawn to an exact scale.

[0056] 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 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.

[0057] It should also be understood that the terms "comprises", "comprising", "has", "including", and / or "including having", 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 individual elements 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.

[0058] 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 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.

[0059] 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 conjunction with the embodiments.

[0060] The optical lens provided by an embodiment of the present invention is composed 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.

[0061] In some embodiments, the first lens may have a positive focal power, with its object side being convex, and its image side may be concave or convex. The second lens may have a negative focal power, with its object side being concave or convex, and its image side being concave. The third lens may have a positive focal power, with its object side being convex, and its image side being concave near the optical axis. The fourth lens may have a negative focal power, with its object side being concave, and its image side may be concave or convex. The fifth lens may have a positive focal power, with its object side being convex near the optical axis; its image side being convex. The sixth lens may have a negative focal power, with its object side being concave, and its image side being convex. The seventh lens may have a negative focal power, with its object side being concave, and its image side being convex. The eighth lens may have a negative focal power, with its object side being concave, and its image side may be concave or convex.

[0062] 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 imaging.

[0063] 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.

[0064] In some embodiments, 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: 9.3mm < IH / Fno < 9.7mm. Satisfying the above conditions can enable the lens to have a large aperture while having a large imaging target surface, ensuring that the lens has a large light flux in a relatively dark environment, thereby improving the picture quality of the lens in different environments.

[0065] In some embodiments, the overall 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: 0.88 < TTL / IH < 0.92. Satisfying the above conditions can better realize the miniaturization of the lens, and at the same time ensure that the lens has a large image surface and can match a large-size imaging chip to achieve high-definition imaging.

[0066] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 0.6 < f1 / f < 0.8. Satisfying the above conditions can make the first lens have a large positive refractive power, while improving the light collection ability of the marginal field of view, reducing the working aperture of the first lens, which is beneficial to achieving the balance of large aperture and small aperture.

[0067] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -1.35 < f2 / f < -0.9. Meeting the above conditions can endow the second lens with a large negative refractive power, which can diverge the incident light to a great extent, thereby effectively increasing the height of the light entering the imaging surface and better achieving large target surface imaging of the lens.

[0068] 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 < 3; the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: 0.4 < R5 / R6 < 0.6. Meeting the above conditions can endow the third lens with an appropriate positive optical power, which is beneficial to the smooth transition of the light trend, improving the imaging quality of the optical lens. At the same time, it can reduce the system sensitivity and improve the manufacturing yield.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -4 < f4 / f < -2; the curvature radius R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -2.5 < R7 / f < -1.5. Meeting the above conditions can effectively reduce the difficulty of correcting the marginal field distortion, 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.

[0070] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.65 < f5 / f < 1; the curvature radius R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 2.5 < R9 / f < 5. 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.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -14 < f6 / f < -2.5; the curvature radius R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -1.4 < R12 / f < -0.8. 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.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -38 < f7 / f < -2; the curvature radius R14 of the image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -2.2 < R14 / f < -1. 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 reducing the exit angle of the light in the marginal field of view by combining the bending of the marginal field of view, thereby improving the relative illumination of the marginal field of view.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -0.8 < f8 / f < -0.5. Meeting the above conditions is beneficial to further diverge the incident light, causing the peripheral light and the central light to turn upwards, reaching a higher imaging position, better realizing large target surface imaging of the lens, and improving the imaging quality.

[0074] In some embodiments, the combined focal length f56 of the fifth lens and the sixth lens and the combined focal length f78 of the seventh lens and the eighth lens satisfy: -2.1 < f56 / f78 < -1.7. 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. At the same time, it is beneficial to balance the distortion and astigmatism generated by the front lenses of the optical lens, and improve the imaging quality of the optical lens.

[0075] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.1 < TTL / f < 1.2. Meeting the above conditions can effectively limit the length of the lens, which is beneficial to realizing the miniaturization of the optical lens.

[0076] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.25 < IH / f < 1.35. Meeting the above conditions is beneficial to realizing the telephoto characteristics of the lens, facilitating the realization of a large image plane of the lens, and thus improving the imaging quality of the optical lens.

[0077] In some embodiments, the back focal length BFL of the optical lens and the overall optical length TTL of the optical lens satisfy: 0.03 < BFL / TTL < 0.08; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.04 < BFL / f < 0.09. Meeting the above conditions, by setting a reasonable optical back focus, while reducing the assembly interference between different components, the lens has a smaller overall length, effectively realizing the miniaturization of the lens.

[0078] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f34 of the third lens and the fourth lens satisfy: -0.2 < f12 / f34 < 0.3. Meeting the above conditions, by reasonably setting the focal length relationship of the first four lenses, the object surface light with a wide field of view angle can be converged into the lens, better correcting the edge distortion of the lens without generating large aberrations; at the same time, it can make the front lens group have appropriate refractive power, which is beneficial to reducing the overall length of the lens.

[0079] 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: 0.65 < ∑CT / TTL < 0.7. Meeting the above conditions can effectively compress the total length of the optical system, making the structure of the system more compact.

[0080] In some embodiments, the optical lens satisfies the conditional formula: 13 mm < f < 13.5 mm, 63° < FOV < 67°, 15 mm < TTL < 15.8 mm, 1.7 < Fno < 1.9, 17 mm < IH < 17.5 mm; 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 aperture value and can achieve high-definition imaging even in a relatively dark environment; it 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 (i.e., the pixel point size is larger), and even in a relatively dark environment, noise can be effectively reduced, the dynamic range will be wider, and more details can be retained in the dark part, so as to present a clearer shooting effect.

[0081] In some embodiments, the lens material of 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.

[0082] 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.

[0083] 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:

[0084]

[0085] 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 coefficient of the 2i-th order.

[0086] The present invention will be further described below with reference to 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, please 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 should be regarded as equivalent substitution methods and are included in the protection scope of the present invention.

[0087] Embodiment 1

[0088] 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: 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, and a filter G1.

[0089] 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;

[0090] The second lens L2 has a negative optical power. Its object side surface S3 is a convex surface, and its image side surface S4 is a concave surface;

[0091] The third lens L3 has a positive optical power. Its object side surface S5 is a convex surface, and its image side surface S6 is a concave surface near the optical axis;

[0092] The fourth lens L4 has a negative optical power. Its object side surface S7 is a concave surface, and its image side surface S8 is a concave surface near the optical axis;

[0093] The fifth lens L5 has a positive optical power. Its object side surface S9 is a convex surface near the optical axis, and its image side surface S10 is a convex surface;

[0094] The sixth lens L6 has a negative optical power. Its object side surface S11 is a concave surface, and its image side surface S12 is a convex surface;

[0095] The seventh lens L7 has a negative optical power. Its object side surface S13 is a concave surface, and its image side surface S14 is a convex surface;

[0096] 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;

[0097] Both the object side S17 and the image side S18 of the filter G1 are flat surfaces;

[0098] The imaging surface S19 is a flat surface.

[0099] 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 made of plastic aspherical lenses.

[0100] The relevant parameters of each lens in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0101] Table 1-1

[0102]

[0103]

[0104] The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0105] Table 1-2

[0106]

[0107]

[0108] In this embodiment, the field curvature curve graph, f~tan(θ) distortion curve graph, axial chromatic 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.

[0109] Figure 2 shows the field curvature curve graph of the optical lens 100 in this embodiment, which represents the bending degree 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 half field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.05 mm, indicating that the optical lens 100 can correct the field curvature well.

[0110] Figure 3 shows the f~tan(θ) distortion curve graph of the optical lens 100 in this embodiment, which represents the distortion of different field angles on the imaging surface. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the distortion value is controlled within 0-2%, indicating that the optical lens 100 can correct the distortion well.

[0111] Figure 4The axial chromatic aberration curve diagram of the optical lens 100 in this embodiment is shown, which represents the chromatic aberration on the optical axis at the imaging plane for each wavelength. The horizontal axis represents the axial chromatic 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 chromatic aberration is controlled within ±0.02 mm, indicating that the optical lens 100 can correct the axial chromatic aberration well.

[0112] Figure 5 The lateral chromatic aberration curve diagram of the optical lens 100 in this embodiment is shown, which represents the chromatic aberration at different image heights on the imaging plane for each wavelength relative to the central wavelength (0.555 μm). 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 ±1.5 μm, indicating that the optical lens 100 can correct the chromatic aberration well.

[0113] Embodiment 2

[0114] 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 difference is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0115] The relevant parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0116] Table 2-1

[0117]

[0118]

[0119] The surface type parameters of the aspherical lenses in the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0120] Table 2-2

[0121]

[0122]

[0123] In this embodiment, the field curvature curve diagram, f~tan(θ) distortion curve diagram, axial chromatic aberration curve diagram, and lateral chromatic aberration curve diagram of the optical lens 200 are respectively as Figure 7 , Figure 8 , Figure 9 , Figure 10 shown.

[0124] From Figure 7It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.06 mm, indicating that the optical lens 200 can correct the field curvature well.

[0125] From Figure 8 it can be seen that the distortion value is controlled within 0 - 2%, indicating that the optical lens 200 can correct the distortion well.

[0126] From Figure 9 it can be seen that the offset of the axial chromatic aberration is controlled within ±0.02 mm, indicating that the optical lens 200 can correct the axial chromatic aberration well.

[0127] From Figure 10 it can be seen that the lateral chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±1.5 μm, indicating that the optical lens 200 can correct the chromatic aberration well.

[0128] Embodiment 3

[0129] 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 object side surface S3 of the second lens L2 is concave; the image side surface S8 of the fourth lens L4 is convex; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0130] The relevant parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0131] Table 3-1

[0132]

[0133]

[0134] The aspheric lens surface type parameters of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0135] Table 3-2

[0136]

[0137]

[0138] In this embodiment, the field curvature curve graph, f~tan(θ) distortion curve graph, axial chromatic 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.

[0139] From Figure 12It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.06 mm, indicating that the optical lens 300 can correct the field curvature well.

[0140] From Figure 13 it can be seen that the distortion value is controlled within 0 - 2%, indicating that the optical lens 300 can correct the distortion well.

[0141] From Figure 14 it can be seen that the offset of the axial chromatic aberration is controlled within ±0.03 mm, indicating that the optical lens 300 can correct the axial chromatic aberration well.

[0142] From Figure 15 it can be seen that the lateral chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±1.5 μm, indicating that the optical lens 300 can correct the chromatic aberration well.

[0143] Embodiment 4

[0144] Please refer to Figure 16 , which shows the structural schematic diagram of the optical lens 400 provided in Embodiment 4 of the present invention. Compared with Embodiment 1, the main differences are: the image side surface S2 of the first lens L1 is a convex surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0145] The relevant parameters of each lens in the optical lens 400 in Embodiment 4 are shown in Table 4 - 1.

[0146] Table 4 - 1

[0147]

[0148]

[0149] The surface type parameters of the aspherical lenses of the optical lens 400 in Embodiment 4 are shown in Table 4 - 2.

[0150] Table 3 - 2

[0151]

[0152]

[0153] In this embodiment, the field curvature curve graph, f~tan(θ) distortion curve graph, axial chromatic 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.

[0154] From Figure 17It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.06 mm, indicating that the optical lens 400 can correct the field curvature well.

[0155] From Figure 18 it can be seen that the distortion value is controlled within 0-2%, indicating that the optical lens 400 can correct the distortion well.

[0156] From Figure 19 it can be seen that the offset of the axial chromatic aberration is controlled within ±0.04 mm, indicating that the optical lens 400 can correct the axial chromatic aberration well.

[0157] From Figure 20 it can be seen that the lateral chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±1.5 μm, indicating that the optical lens 400 can correct the chromatic aberration well.

[0158] Embodiment 5

[0159] Please refer to Figure 21 , which shows the structural schematic diagram of the optical lens 500 provided in Embodiment 5 of the present invention. Compared with Embodiment 1, the main difference is that: 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.

[0160] The relevant parameters of each lens in the optical lens 500 in Embodiment 5 are shown in Table 5-1.

[0161] Table 5-1

[0162]

[0163]

[0164] The aspheric lens surface type parameters of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0165] Table 3-2

[0166]

[0167]

[0168] In this embodiment, the field curvature curve graph, f~tan(θ) distortion curve graph, axial chromatic aberration curve graph, and lateral chromatic aberration curve graph of the optical lens 500 are respectively as Figure 22 , Figure 23 , Figure 24 , Figure 25 shown.

[0169] From Figure 22It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.06 mm, indicating that the optical lens 500 can correct the field curvature well.

[0170] From Figure 23 it can be seen that the distortion value is controlled within 0-2%, indicating that the optical lens 500 can correct the distortion well.

[0171] From Figure 24 it can be seen that the offset of the axial chromatic aberration is controlled within ±0.03 mm, indicating that the optical lens 500 can correct the axial chromatic aberration well.

[0172] From Figure 25 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 500 can correct the chromatic aberration well.

[0173] Please refer to Table 6 for the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the f-number Fno, the true image height IH corresponding to the maximum field of view angle, the chief ray angle of incidence CRA at the maximum image height, the maximum field of view angle FOV, and the values corresponding to each conditional formula in each embodiment.

[0174] Table 4

[0175]

[0176]

[0177] Based on the above embodiments, the optical lens provided by the present invention has at least the following advantages:

[0178] (1) By setting a specific surface shape and reasonably distributing the optical power, the overall length of the optical lens can be effectively shortened, which is beneficial to better realizing the miniaturization of the optical lens; at the same time, it has a large aperture and can achieve high-definition imaging even in a dim environment.

[0179] (2) It realizes the large target surface characteristic of the lens, can match an imaging chip with a larger target surface to achieve high-definition imaging, and with the increase of the target surface, the pixel distribution can be sparser (i.e., the pixel size is larger), and even in a relatively dark environment, noise can be effectively reduced, the dynamic range will be wider, and more details can be retained in the dark part, so as to present a clearer shooting effect; at the same time, it can reasonably correct the overall aberration of the optical lens, make the optical lens have high pixels, and improve the imaging quality of the optical lens.

[0180] 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 any one or more embodiments or examples in a suitable manner.

[0181] The above-described embodiments merely represent several implementation manners of the present invention. The descriptions thereof are relatively specific and detailed, but should not be construed as a limitation to 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 shall be subject to the appended claims.

Claims

1. An optical lens, which is composed of eight lenses, is characterized in that, Along the optical axis from the object side to the imaging surface, it includes: A first lens having positive optical power, whose object side surface is convex; A second lens having negative optical power, whose image side surface is concave; The third lens has positive refractive power, its object side surface is convex, and its image side surface is concave near the optical axis; a fourth lens element having negative optical power and a concave object side surface; The fifth lens element has positive refractive power, and its object side surface is convex at the near optical axis; its image side surface is convex; a sixth lens having negative optical power, whose object side surface is concave and whose image side surface is convex; The seventh lens element has a negative optical power, and its object side surface is concave and its image side surface is convex; an eighth lens having negative optical power, whose object side surface is concave; The real image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 9.3mm <IH / Fno<9.7mm。 2. The optical lens according to claim 1, wherein The total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.88 <TTL / IH<0.92。 3. 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: 0.6 <f1 / f<0.8。 4. 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: -1.35 <f2 / f<-0.9。 5. 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: <f3 / f<3;所述第三透镜的物侧面曲率半径R5与所述第三透镜的像侧面曲率半径R6满足:0.4<R5 / R6<0.6。 6. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: <f4 / f<-2;所述第四透镜的物侧面曲率半径R7与所述光学镜头的有效焦距f满足:-2.5<R7 / f<-1.5。 7. 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: 0.65 <f5 / f<1。 8. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: <f6 / f<-2.5;所述第六透镜的像侧面曲率半径R12与所述光学镜头的有效焦距f满足:-1.4<R12 / f<-0.8。 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: -38 <f7 / f<-2;所述第七透镜的像侧面曲率半径R14与所述光学镜头的有效焦距f满足:-2.2<R14 / f<-1。 10. The optical lens according to claim 1, wherein, The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -0.8 <f8 / f<-0.5。 11. The optical lens according to claim 1, characterized in that, The combined focal length f56 of the fifth lens and the sixth lens and the combined focal length f78 of the seventh lens and the eighth lens satisfy: -2.1 <f56 / f78<-1.7。

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