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 negative focal power, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with negative focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the object side surface and the image side surface of the third lens are convex surfaces; 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 image side surface of the fifth lens is a convex surface; the sixth lens has positive focal power, and the object side surface and the image side surface of the sixth lens are convex surfaces; the object side surface and the image side surface of the seventh lens are concave surfaces; the object side surface of the eighth lens is a convex surface, and the image side surface of the eighth lens is a concave surface. According to the optical lens provided by the invention, through specific surface shape matching and reasonable focal power distribution, the lens has one or more advantages of a large field angle, a large image plane, a large aperture, high imaging quality and the like.

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 continuous improvement of people's requirements for driving experience, in-vehicle application optical lenses are increasingly used in intelligent driving, and the status of in-vehicle optical lenses in the automotive-related industry is constantly rising.

[0003] Advanced Driver Assistance Systems (ADAS) play an important role in intelligent driving. It collects environmental information through various lenses and sensors to ensure the driving safety of drivers. In addition to requiring the optical lens to have a thin, light, short and small shape and high pixel and high resolution characteristics, the existing ADAS system lenses also require the optical lens to be able to clearly image under low illuminance conditions. Therefore, it is necessary to develop an optical lens with good imaging effect. Summary of the Invention

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

[0005] The technical solution adopted by the present invention is as follows: An optical lens, comprising a total of eight lenses, which in sequence from the object side to the imaging surface along the optical axis include: A first lens with negative optical power, the object side surface of which is convex and the image side surface of which is concave; A second lens with negative optical power, the object side surface of which is concave and the image side surface of which is convex; A third lens with positive optical power, both the object side surface and the image side surface of which are convex; A fourth lens with negative optical power, the object side surface of which is concave; A fifth lens with positive optical power, the image side surface of which is convex; A sixth lens with positive optical power, both the object side surface and the image side surface of which are convex; A seventh lens with negative optical power, both the object side surface and the image side surface of which are concave; An eighth lens with positive optical power, the object side surface of which is convex and the image side surface of which is concave; Wherein, the radius of curvature R8 of the image side surface of the fourth lens and the radius of curvature R9 of the object side surface of the fifth lens satisfy: 1.3 < (R8 - R9) / (R8 + R9) < 32.

[0006] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 8 < TTL / f < 10; 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: 3.5 < TTL / IH < 4.4.

[0007] Further preferably, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 84° < FOV / Fno < 89°; the true image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.5 < IH / EPD < 4.5.

[0008] Further preferably, the true image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 2 < IH / f < 2.5; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.8 < BFL / f < 1.1.

[0009] Further preferably, the total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view of the optical lens, and the maximum field of view FOV of the optical lens satisfy: 16 < TTL / (IH / 2) / (FOV / 2)×180° < 20; the clear aperture diameter d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field of view of the optical lens, and the maximum field of view FOV of the optical lens satisfy: 0.25 < d1 / (IH / 2) / tan(FOV / 2) < 0.5.

[0010] Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -25 < f4 / f < -6.5; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 2.7 < f5 / f < 6.5; 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: 2.5 < f5678 / f < 2.8.

[0011] Further preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -2 < f7 / f < -1.2; the object side surface curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.9 < R13 / f < -1.3; the image side surface curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 2.7 < R14 / f < 6.1.

[0012] Further preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 3.8 < f8 / f < 4.2; the object side surface curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.6 < R15 / f < 1.9; the image side surface curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 10 < R16 / f < 17.

[0013] Further preferably, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -8.8 < f4 / f5 < -1; the image-side curvature radius R8 of the fourth lens and the object-side curvature radius R9 of the fifth lens satisfy: -7 < R8 / R9 < -1.

[0014] Further preferably, the object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -3.2 < (R13 - R14) / (R13 + R14) < -1.7; the object-side curvature radius R15 of the eighth lens and the image-side curvature radius R16 of the eighth lens satisfy: -1.5 < (R15 + R16) / (R15 - R16) < -1.2.

[0015] The optical lens provided by the present invention adopts eight lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberration, improve the imaging quality of the optical lens, and enable the lens to have one or more advantages such as a large field of view angle, a large image plane, a large aperture, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, wherein: Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0017] Figure 2 is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 3 is the MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0019] Figure 4 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0020] Figure 5 is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0021] Figure 6 is the MTF curve graph of the optical lens in Embodiment 2 of the present invention.

[0022] Figure 7 is a schematic structural diagram of the optical lens in Embodiment 3 of the present invention.

[0023] Figure 8 is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0024] Fig. 9 This is the MTF curve diagram of the optical lens in Example 3 of the present invention.

[0025] Fig.10 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

[0026] Fig.11 : is the F-Tan (Theta) distortion curve of the optical lens in Example 4 of the present invention.

[0027] Fig.12 This is the MTF curve diagram of the optical lens in Example 4 of the present invention.

[0028] Fig.13 Schematic diagram of the structure of the optical lens in Example 5 of the present invention.

[0029] Fig.14 : is the F-Tan (Theta) distortion curve of the optical lens in Example 5 of the present invention.

[0030] Fig.15 This is the MTF curve diagram of the optical lens in Example 5 of the present invention.

[0031] Fig.16 Schematic diagram of the structure of the optical lens in Example 6 of the present invention.

[0032] Fig.17 : is the F-Tan (Theta) distortion curve of the optical lens in Example 6 of the present invention.

[0033] Fig.18 This is the MTF curve diagram of the optical lens in Example 6 of the present invention.

[0034] Fig.19 Schematic diagram of the structure of the optical lens in Example 7 of the present invention.

[0035] Fig. 20 : is the F-Tan (Theta) distortion curve of the optical lens in Example 7 of the present invention.

[0036] Fig.21 This is the MTF curve diagram of the optical lens in Example 7 of the present invention.

[0037] Fig. 22 Schematic diagram of the structure of the optical lens in Example 8 of the present invention.

[0038] Fig.23 : is the F-Tan (Theta) distortion curve of the optical lens in Example 8 of the present invention.

[0039] Fig.24This is the MTF curve diagram of the optical lens in Example 8 of the present invention.

[0040] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0041] In order to better understand the present application, a more detailed description will be made of 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 are not intended to 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.

[0042] It should be noted that in this specification, the expressions of 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 teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0043] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0044] 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 is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0045] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", 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 expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0046] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0047] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0048] The optical lens provided by the embodiment of the present invention comprises eight lenses in total, 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.

[0049] In some embodiments, the first lens may have a negative optical power, and its object side surface is convex, and its image side surface is concave. The second lens may have a negative optical power, and its object side surface is concave, and its image side surface is convex. The third lens may have a positive optical power, and its object side surface and image side surface are both convex. The fourth lens may have a negative optical power, and its object side surface is concave, and its image side surface may be concave or convex. The fifth lens may have a positive optical power, and its object side surface may be concave or convex, and its image side surface is convex. The sixth lens may have a positive optical power, and its object side surface and image side surface are both convex. The seventh lens may have a negative optical power, and its object side surface and image side surface are both concave. The eighth lens may have a positive optical power, and its object side surface is convex, and its image side surface is concave.

[0050] In some embodiments, the optical lens may further include an aperture, which may be located between the fourth lens and the fifth lens. It is understandable that the aperture is used to limit the amount of light entering to change the brightness of the image. In addition, when the aperture is located between the fourth lens and the fifth lens, the aperture can reasonably distribute the effects of the first lens to the eighth lens. For example, the first lens, the second lens, the third lens, and the fourth lens can be used to receive light to a greater extent, and the fifth lens to the eighth lens can be used to correct the aberration, which is beneficial to balance the structure of the entire optical system. In addition, when the aperture is located between the fourth lens and the fifth lens, it is convenient to correct the aperture aberration.

[0051] In some embodiments, the optical lens may further include a filter, which is disposed between the eighth lens and the imaging surface. The filter is used to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0052] In some embodiments, the sixth lens and the seventh lens can be glued together to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens. It can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0053] In some embodiments, the radius of curvature R8 of the image side of the fourth lens and the radius of curvature R9 of the object side of the fifth lens satisfy: 1.3 < (R8 - R9) / (R8 + R9) < 32. By satisfying the above range and controlling the radii of curvature of the lenses before and after the aperture, the stray light of the optical lens can be effectively controlled, the formation of ghost images can be reduced, and the imaging quality of the optical lens can be improved. More specifically, 1.33 < (R8 - R9) / (R8 + R9) < 31.86.

[0054] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 8 < TTL / f < 10. By satisfying the above range, the length of the lens can be effectively limited, which is beneficial to the miniaturization of the optical lens. More specifically, 8.1 < TTL / f < 9.96.

[0055] 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: 3.5 < TTL / IH < 4.4. By satisfying the above range, when the total length of the lens is the same, a larger image plane can be ensured, which can match a larger-sized imaging chip to achieve high-definition imaging, and better achieve the balance between the small total length and the large image plane of the lens. More specifically, 3.58 < TTL / IH < 4.37.

[0056] In some embodiments, the maximum field of view angle FOV of the optical lens and the f-number Fno of the optical lens satisfy: 84° < FOV / Fno < 89°. By satisfying the above range, the optical lens is limited to have a suitable field of view angle and f-number, and can collect light at large angles and obtain good imaging quality. More specifically, 84.2° < FOV / Fno < 88.25°.

[0057] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.5 < IH / EPD < 4.5. By satisfying the above range, the width of the light beam incident on the optical lens can be increased, so that the brightness at the image plane of the optical lens can be improved and vignetting can be avoided. More specifically, 3.65 < IH / EPD < 4.45.

[0058] 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: 2 < IH / f < 2.5. Meeting the above range and controlling the image height and focal length of the optical lens within a reasonable range helps the optical lens to have the characteristic of a large image plane and improve the imaging quality. More specifically, 2.14 < IH / f < 2.4.

[0059] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.8 < BFL / f < 1.1. Meeting the above range and defining that the optical lens has an appropriate back focus facilitate the reasonable arrangement of the positions of the respective lenses and reduce the processing and assembly difficulty at the same time. More specifically, 0.82 < BFL / f < 1.1.

[0060] In some embodiments, the overall optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 16 < TTL / (IH / 2) / (FOV / 2)×180° < 20. Meeting the above range and restricting the length of the optical lens under the condition of the same imaging area and the same field of view angle realizes the miniaturization of the optical lens. More specifically, 16.15 < TTL / (IH / 2) / (FOV / 2)×180° < 19.65.

[0061] In some embodiments, the clear aperture d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.25 < d1 / (IH / 2) / tan(FOV / 2) < 0.5. Meeting the above range can have a small front aperture while meeting the requirements of the optical lens having a large field of view angle and a large image plane. More specifically, 0.27 < d1 / (IH / 2) / tan(FOV / 2) < 0.47.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -25 < f4 / f < -6.5. Meeting the above range and defining that the fourth lens has an appropriate negative optical power can diverge the light rays emitted by the third lens, making the light rays in the marginal field of view show an upward trend, which is beneficial for the image points on the imaging plane to be away from the optical axis, so as to be conducive to achieving the effect of matching with a large chip, obtaining a larger picture, effectively eliminating aberrations, and improving the resolution ability of the optical lens. More specifically, -24.75 < f4 / f < -6.81.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 2.7 < f5 / f < 6.5; the image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -3.9 < R10 / f < -2. Meeting the above ranges and setting the fifth lens to have a positive refractive power and a suitable surface shape is beneficial to converging light while correcting the field curvature and distortion of the optical lens, and improving the imaging quality of the optical lens. More specifically, 2.74 < f5 / f < 6.45; -3.85 < R10 / f < -2.01.

[0064] 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: 2.5 < f5678 / f < 2.8. Meeting the above range and reasonably setting the relationship of the lens group behind the aperture is beneficial to balancing various aberrations generated by the lens group in front of the aperture and improving the overall imaging quality. More specifically, 2.5 < f5678 / f < 2.77.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -2 < f7 / f < -1.2; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.9 < R13 / f < -1.3; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 2.7 < R14 / f < 6.1. Meeting the above ranges and setting the seventh lens to have a negative refractive power and a bi-concave surface shape can effectively balance various aberrations generated by the front lens group. At the same time, it is beneficial to increase the divergence degree of light, increase the area of light entering the imaging surface, realize large-format imaging of the lens, and improve the imaging quality of the optical lens. More specifically, -1.93 < f7 / f < -1.24; -1.83 < R13 / f < -1.3; 2.72 < R14 / f < 6.02.

[0066] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 3.8 < f8 / f < 4.2; the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.6 < R15 / f < 1.9; the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 10 < R16 / f < 17. Meeting the above ranges and setting the eighth lens to have a positive refractive power and a suitable surface shape is beneficial to light convergence, enabling the light trend to smoothly transition to the rear, reducing the height of the light incident on the rear, slowing down the upward trend of the light, avoiding light energy loss caused by too large a chief ray angle between the large field-of-view light and the chip when reaching the imaging surface, facilitating the improvement of the illuminance of the edge field of view, and being conducive to achieving a short overall optical length. More specifically, 3.85 < f8 / f < 4.16; 1.65 < R15 / f < 1.85; 10.13 < R16 / f < 16.14.

[0067] In some embodiments, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -8.8 < f4 / f5 < -1; the image-side curvature radius R8 of the fourth lens and the object-side curvature radius R9 of the fifth lens satisfy: -7 < R8 / R9 < -1. Meeting the above ranges is beneficial to the smooth transition of light, beneficial to correcting the aberration of the optical lens, and improving the imaging quality of the optical lens. More specifically, -8.77 < f4 / f5 < -1.05; -6.95 < R8 / R9 < -1.05.

[0068] In some embodiments, the object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -3.2 < (R13 - R14) / (R13 + R14) < -1.7. Meeting the above range is beneficial to increasing the area of light entering the imaging surface, realizing large-format imaging of the lens, and improving the imaging quality of the optical lens. More specifically, -3.11 < (R13 - R14) / (R13 + R14) < -1.72.

[0069] In some embodiments, the object-side curvature radius R15 of the eighth lens and the image-side curvature radius R16 of the eighth lens satisfy: -1.5 < (R15 + R16) / (R15 - R16) < -1.2. Meeting the above range is beneficial to suppressing the angle of the edge field of view incident on the imaging surface, effectively transmitting more light beams to the imaging surface, and at the same time being able to balance the field curvature and spherical aberration of the optical lens, and improving the imaging quality of the optical lens. More specifically, -1.42 < (R15 + R16) / (R15 - R16) < -1.23.

[0070] In some embodiments, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis satisfy: 0.4 < ∑CT / TTL < 0.6. Satisfying the above range can effectively compress the total length of the optical lens, and is beneficial to the structural design and production process of the optical lens. More specifically, 0.44 < ∑CT / TTL < 0.6.

[0071] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis and the effective focal length f of the optical lens satisfy: 4.6 < ΣCT / f < 6.5. Satisfying the above range can effectively correct the field curvature and distortion of the optical lens and improve the imaging quality of the optical lens. More specifically, 4.64 < ΣCT / f < 6.42.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.2 < f1 / f < -1.7. Satisfying the above range, by setting the first lens to have a negative refractive power, it is beneficial for the first lens to accommodate a larger angle of light and collect as much light as possible into the rear optical system, achieving a large field of view while increasing the light flux. More specifically, -2.15 < f1 / f < -1.75.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -73 < f2 / f < -4.9. Satisfying the above range makes the second lens have a negative optical power and has the effect of diverging light. At the same field of view angle, it further diverges the light emerging from the image side of the first lens, and can disperse the central light and marginal light of each field of view, enabling the rear optical system to have a larger light receiving surface to receive the light emerging from the image side of the second lens, achieving a larger light input and being beneficial to increasing the relative illuminance. More specifically, -72.57 < f2 / f < -4.91.

[0074] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2.9 < f3 / f < 3.6. Satisfying the above range limits the third lens to have an appropriate positive optical power and has the effect of converging light, reducing the height of peripheral light and being beneficial to reducing the aperture of the rear lens. More specifically, 2.94 < f3 / f < 3.6.

[0075] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 2 < f6 / f < 2.3; the radius of curvature R11 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 2 < R11 / f < 2.7. Satisfying the above ranges, defining that the sixth lens has a positive optical power and a suitable surface shape is beneficial to light convergence. And by combining the sixth lens with a positive optical power and the seventh lens with a negative optical power, the optical path difference between different fields of view can be adjusted, the resolution can be improved, it is beneficial for light to enter the rear lens smoothly, and further the field curvature can be reduced and the off-axis aberration of the optical lens can be corrected. More specifically, 2.02 < f6 / f < 2.3; 2.07 < R11 / f < 2.64.

[0076] In some embodiments, the combined focal length f67 of the sixth lens and the seventh lens and the combined focal length f5678 of the fifth, sixth, seventh, and eighth lenses satisfy: -37 < f67 / f5678 < -1.5. Satisfying the above range, defining the focal length relationship between the cemented lens group and the rear diaphragm lens group can effectively correct chromatic aberration, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens. More specifically, -36.36 < f67 / f5678 < -1.66.

[0077] In some embodiments, the optical lens satisfies the following conditional expressions: 4.6 mm < f < 5 mm; 140° < FOV < 170°; 2.5 mm < EPD < 3 mm; 39 mm < TTL < 49 mm; 1.6 < Fno < 2; 10 mm < IH < 12 mm; 18° < CRA < 21°; 3.9 mm < BFL < 5.5 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the overall optical length of the optical lens, FNO represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the chief ray incident angle of the optical lens, and BFL represents the back focal length of the optical lens. Satisfying the above ranges, the optical lens has at least one or more advantages such as a large image plane, a large aperture, and a large field of view angle. More specifically, 4.64 mm < f < 4.94 mm; 2.5 mm < EPD < 2.91 mm; 39.9 mm < TTL < 48.1 mm; 1.69 < Fno < 1.91; 18.15° < CRA < 20.05°; 3.96 mm < BFL < 5.41 mm; 149° < FOV < 161°; 10.62 mm < IH < 11.15 mm.

[0078] In some embodiments, the lens material in the optical lens provided by the present invention may be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. When the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The optical lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0079] 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 may be spherical lenses or aspherical lenses. Compared with spherical structures, aspherical structures can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of lenses, and better realizing miniaturization of lenses. More specifically, the second lens, the fifth lens, and the eighth lens of the present invention are aspherical lenses; the first lens, the third lens, the fourth lens, the sixth lens, and the seventh lens are spherical lenses.

[0080] In various embodiments of the present invention, when the lens is an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations: ; Among them, z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the surface vertex, K is the quadratic surface coefficient, B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients respectively.

[0081] The present invention is further described below in multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different. For specific differences, please refer to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any other changes, substitutions, combinations or simplifications that do not deviate 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.

[0082] Example 1 See also Figure 1 , shown is a schematic diagram of the structure of the optical lens 100 provided in Example 1 of the present invention, and the optical lens 100 includes, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7 and a filter G1.

[0083] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave; The second lens L2 has negative refractive power, its object side surface S3 is concave, and its image side surface S4 is convex; The third lens L3 has positive refractive power, and its object-side surface S5 and image-side surface S6 are both convex; The fourth lens L4 has negative refractive power, its object-side surface S7 is concave, and its image-side surface S8 is convex; The fifth lens L5 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is convex; The sixth lens L6 has positive refractive power, its object-side surface S11 is convex, and its image-side surface is convex; The seventh lens L7 has negative refractive power, its object-side surface is concave, and its image-side surface S13 is concave; The sixth lens L6 and the seventh lens L7 form a cemented lens group with negative refractive power, that is, the cemented surface between the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7 is S12; The eighth lens L8 has positive refractive power, its object-side surface S14 is convex, and its image-side surface S15 is concave; The object side surface S16 and the image side surface S17 of the filter are both planes; The imaging surface S18 is a plane.

[0084] The second lens L2, the fifth lens L5 and the eighth lens L8 are glass aspherical lenses; the first lens L1, the third lens L3, the fourth lens L4, the sixth lens L6 and the seventh lens L7 are glass spherical lenses.

[0085] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1.

[0086] Table 1 The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0087] Table 1-2 In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 shown.

[0088] Figure 2The F-Tan (Theta) distortion curve of Example 1 is shown, which represents the F-Tan (Theta) distortion of light of different wavelengths at different image heights on the imaging surface, the horizontal axis represents the F-Tan (Theta) distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the F-Tan (Theta) distortion of the optical lens is controlled within -75%~0, indicating that the optical lens can correct the distortion well.

[0089] Figure 3 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF value of this embodiment is above 0.3 in the entire field of view, and in the range of 0 to 180 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency conditions.

[0090] Example 2 See also Figure 4 , shown is a schematic diagram of the structure of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0091] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2.

[0092] Table 2 The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0093] Table 2-2 In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 200 are respectively as follows: Figure 5 , Figure 6 As shown. Figure 5 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -80%~0, indicating that the optical lens can correct the distortion well. Figure 6 It can be seen that the MTF value of this embodiment is above 0.38 in the whole field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0094] Example 3 See also Figure 7 , shown is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0095] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3.

[0096] Table 3 The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0097] Table 3-2 In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 300 are respectively as follows: Figure 8 , Fig. 9 As shown. Figure 8 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -80%~0, indicating that the optical lens can correct the distortion well. Fig. 9 It can be seen that the MTF value of this embodiment is above 0.3 in the whole field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0098] Example 4 See also Fig.10 , shown is a schematic diagram of the structure of an optical lens 400 provided in Example 4 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

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

[0100] Table 4 The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0101] Table 4-2 In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 400 are respectively as follows: Fig.11 , Fig.12As shown. Fig.11 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -80%~0, indicating that the optical lens can correct the distortion well. Fig.12 It can be seen that the MTF value of this embodiment is above 0.3 in the whole field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0102] Example 5 See also Fig.13 , shown is a schematic diagram of the structure of the optical lens 500 provided in Example 5 of the present invention. Compared with Example 1, the main differences of this embodiment are: the image side surface S8 of the fourth lens L4 is a concave surface; the object side surface S9 of the fifth lens L5 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0103] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5.

[0104] Table 5 The surface parameters of the aspheric lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0105] Table 5-2 In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 500 are respectively as follows: Fig.14 , Fig.15 As shown. Fig.14 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -80%~0, indicating that the optical lens can correct the distortion well. Fig.15 It can be seen that the MTF value of this embodiment is above 0.4 in the whole field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0106] Example 6 See also Fig.16 , shown is a schematic diagram of the structure of an optical lens 600 provided in Example 6 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image side surface S8 of the fourth lens L4 is a concave surface; the object side surface S9 of the fifth lens L5 is a concave surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0107] The relevant parameters of each lens in the optical lens 600 in Example 6 are shown in Table 6.

[0108] Table 6 The surface parameters of the aspheric lens of the optical lens 600 in Example 6 are shown in Table 6-2.

[0109] Table 6-2 In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 600 are respectively as follows: Fig.17 , Fig.18 As shown. Fig.17 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -80%~0, indicating that the optical lens can correct the distortion well. Fig.18 It can be seen that the MTF value of this embodiment is above 0.4 in the whole field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0110] Example 7 See also Fig.19 , shown is a schematic diagram of the structure of an optical lens 700 provided in Example 7 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image side surface S8 of the fourth lens L4 is a concave surface; the object side surface S9 of the fifth lens L5 is a concave surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0111] The relevant parameters of each lens in the optical lens 700 in Example 7 are shown in Table 7.

[0112] Table 7 The surface parameters of the aspheric lens of the optical lens 700 in Example 7 are shown in Table 7-2.

[0113] Table 7-2 In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 700 are respectively as follows: Fig. 20 , Fig.21 As shown. Fig. 20 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -80%~0, indicating that the optical lens can correct the distortion well. Fig.21It can be seen that the MTF value of this embodiment is above 0.4 in the whole field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0114] Example 8 See also Fig. 22 , shown is a schematic diagram of the structure of the optical lens 800 provided in Example 8 of the present invention. Compared with Example 1, the main differences of this embodiment are: the image side surface S8 of the fourth lens L4 is a concave surface; the object side surface S9 of the fifth lens L5 is a concave surface; 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 800 in Example 8 are shown in Table 8.

[0116] Table 8 The surface parameters of the aspheric lens of the optical lens 800 in Example 8 are shown in Table 8-2.

[0117] Table 8-2 In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 800 are respectively as follows: Fig.23 , Fig.24 As shown. Fig.23 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -80%~0, indicating that the optical lens can correct the distortion well. Fig.24 It can be seen that the MTF value of this embodiment is above 0.3 in the whole field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0118] Please refer to Table 9, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the real image height IH corresponding to the maximum field of view angle, the maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0119] Table 9 In summary of the above embodiments, the optical lens provided by the present invention adopts eight lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it is possible to improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, so that the lens has one or more advantages such as a large field of view, a large image surface, a large aperture, and high imaging quality.

[0120] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0121] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which 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 attached 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 negative optical power, whose object side is convex and whose image side is concave; A second lens with negative optical power, whose object side is concave and whose image side is convex; A third lens with positive optical power, whose object side and image side are both convex; A fourth lens with negative optical power, whose object side is concave; A fifth lens with positive optical power, whose image side is convex; A sixth lens with positive optical power, whose object side and image side are both convex; A seventh lens with negative optical power, whose object side and image side are both concave; An eighth lens with positive optical power, whose object side is convex and whose image side is concave; Wherein, the radius of curvature R8 of the image side of the fourth lens and the radius of curvature R9 of the object side of the fifth lens satisfy: 1.3 < (R8 - R9) / (R8 + R9) < 32.

2. The optical lens according to claim 1, characterized in that: The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 8 < TTL / f < 10; 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: 3.5 < TTL / IH < 4.

4.

3. The optical lens according to claim 1, characterized in that: The maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 84° < FOV / Fno < 89°; The true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.5 < IH / EPD < 4.

5.

4. The optical lens according to claim 1, characterized in that: 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: 2 < IH / f < 2.5; The effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.8 < BFL / f < 1.

1.

5. The optical lens according to claim 1, characterized in that: The total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 16 < TTL / (IH / 2) / (FOV / 2)×180° < 20; The clear aperture diameter d1 of the object side of the first lens, the true image height IH corresponding to the maximum field of view angle of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 0.25 < d1 / (IH / 2) / tan(FOV / 2) < 0.

5.

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: -25 < f4 / f < -6.5; The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 2.7 < f5 / f < 6.5; 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: 2.5 < f5678 / f < 2.

8.

7. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -2 < f7 / f < -1.2; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.9 < R13 / f < -1.3; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 2.7 < R14 / f < 6.

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 f8 of the eighth lens satisfy: 3.8 < f8 / f < 4.2; the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.6 < R15 / f < 1.9; the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 10 < R16 / f < 17.

9. The optical lens according to claim 1, characterized in that: The focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -8.8 < f4 / f5 < -1; the image-side curvature radius R8 of the fourth lens and the object-side curvature radius R9 of the fifth lens satisfy: -7 < R8 / R9 < -1.

10. The optical lens according to claim 1, characterized in that: The object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -3.2 < (R13 - R14) / (R13 + R14) < -1.7; the object-side curvature radius R15 of the eighth lens and the image-side curvature radius R16 of the eighth lens satisfy: -1.5 < (R15 + R16) / (R15 - R16) < -1.2.

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