Optical lens

Abstract

The invention provides an optical lens, which comprises eight lenses with focal power, and sequentially comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with negative focal power and a fourth lens with negative focal power from an object side to an imaging surface along an optical axis, the second lens has negative focal power; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a concave surface; the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface; the object side surface of the sixth lens is a concave surface, and the image side surface of the sixth lens is a concave surface; the object side surface of the seventh lens is a convex 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, and the image 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 application relates to the technical field of imaging lenses, and particularly to an optical lens. BACKGROUND

[0002] With the increasing demand for driving experience, vehicle application type optical lenses are increasingly used in intelligent driving, and the status of vehicle optical lenses in the automotive industry is continuously improving.

[0003] Advanced Driver Assistance System (ADAS) plays an important role in intelligent driving, which collects environmental information through various lenses combined with sensors to ensure the safety of drivers. In addition to the requirements of light, thin, small shape and high pixel, high resolution of the optical lens of the existing ADAS system, the optical lens is required to clearly image under low illumination conditions, so it is necessary to develop an optical lens with good imaging effect. SUMMARY

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

[0005] To achieve the above purpose, the technical scheme adopted by the present application is:

[0006] An optical lens has eight lenses with optical power, which includes, along the optical axis from the object side to the imaging surface:

[0007] a first lens with negative optical power;

[0008] a second lens with negative optical power;

[0009] a third lens with negative optical power, the object side surface of which is convex, and the image side surface of which is concave;

[0010] a fourth lens with positive optical power, the object side surface of which is convex, and the image side surface of which is concave;

[0011] a fifth lens with positive optical power, the object side surface of which is convex, and the image side surface of which is convex;

[0012] a sixth lens with negative optical power, the object side surface of which is concave, and the image side surface of which is concave;

[0013] a seventh lens with positive optical power, the object side surface of which is convex, and the image side surface of which is convex;

[0014] an eighth lens with negative optical power, the object side surface of which is concave, and the image side surface of which is concave;

[0015] The image-side surface curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: 4.3 < R8 / f < 27; the object-side surface curvature radius R7 of the fourth lens and the image-side surface curvature radius R8 of the fourth lens satisfy: 0 < R7 / R8 < 0.25.

[0016] Further preferably, the object-side surface curvature radius R7 of the fourth lens and the image-side surface curvature radius R8 of the fourth lens satisfy: -1 < (R7-R8) / (R7+R8) < -0.6.

[0017] Further preferably, the object-side surface curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: -1.65 < R15 / f < -0.9.

[0018] Further preferably, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: 0.75 < f2 / f3 < 1.1.

[0019] Further preferably, the back focal length BFL of the optical lens and the total track length TTL of the optical lens satisfy: 0 < BFL / TTL < 0.1.

[0020] Further preferably, the effective focal length f of the optical lens, the real image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 50° < f x FOV / IH < 60°.

[0021] Further preferably, the image-side half-hydraulic radius sag16 of the eighth lens, the object-side half-hydraulic radius sag15 of the eighth lens, and the central thickness CT8 of the eighth lens satisfy: 0.55 < (SAG16-SAG15) / CT8 < 0.95.

[0022] Further preferably, the object-side half-hydraulic radius d1 of the first lens and the image-side half-hydraulic radius d16 of the eighth lens satisfy: 1 < d1 / d16 < 1.8.

[0023] Further preferably, the combined focal length f13 of the first lens, the second lens, and the third lens and the combined focal length f48 of the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy: -4.2 < f13 / f48 < -3.

[0024] Further preferably, the combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: 3.5 < f56 / f < 12.

[0025] The optical lens provided by the application adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens is improved, the aberration is reduced, and the imaging quality of the optical lens is improved, so that the lens has one or more advantages of large aperture, long focus, high pixel, high imaging quality and the like. BRIEF DESCRIPTION OF DRAWINGS

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

[0027] Figure 1 It is a structure schematic diagram of the optical lens in the embodiment 1 of the application.

[0028] Figure 2 It is a field curvature curve diagram of the optical lens in the embodiment 1 of the application.

[0029] Figure 3 It is an axial aberration curve diagram of the optical lens in the embodiment 1 of the application.

[0030] Figure 4 It is a lateral chromatic aberration curve diagram of the optical lens in the embodiment 1 of the application.

[0031] Figure 5 It is an MTF curve diagram of the optical lens in the embodiment 1 of the application.

[0032] Figure 6 It is a structure schematic diagram of the optical lens in the embodiment 2 of the application.

[0033] Figure 7 It is a field curvature curve diagram of the optical lens in the embodiment 2 of the application.

[0034] Figure 8 It is an axial aberration curve diagram of the optical lens in the embodiment 2 of the application.

[0035] Figure 9 It is a lateral chromatic aberration curve diagram of the optical lens in the embodiment 2 of the application.

[0036] Figure 10 It is an MTF curve diagram of the optical lens in the embodiment 2 of the application.

[0037] Figure 11 It is a structure schematic diagram of the optical lens in the embodiment 3 of the application.

[0038] Figure 12 It is a field curvature curve diagram of the optical lens in the embodiment 3 of the application.

[0039] Figure 13 It is an axial aberration curve diagram of the optical lens in the embodiment 3 of the application.

[0040] Figure 14 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0041] Figure 15 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0042] Figure 16 This is a schematic diagram of the optical lens structure in Embodiment 4 of the present invention.

[0043] Figure 17 This is a field curvature curve diagram of the optical lens in Embodiment 4 of the present invention.

[0044] Figure 18 This is an axial aberration curve of the optical lens in Embodiment 4 of the present invention.

[0045] Figure 19 This is a chromatic aberration curve of the optical lens in Embodiment 4 of the present invention.

[0046] Figure 20 This is the MTF curve of the optical lens in Embodiment 4 of the present invention.

[0047] Figure 21 This is a schematic diagram of the optical lens structure in Embodiment 5 of the present invention.

[0048] Figure 22 This is a field curvature curve diagram of the optical lens in Embodiment 5 of the present invention.

[0049] Figure 23 This is an axial aberration curve of the optical lens in Embodiment 5 of the present invention.

[0050] Figure 24 This is a chromatic aberration curve of the optical lens in Embodiment 5 of the present invention.

[0051] Figure 25 This is the MTF curve of the optical lens in Embodiment 5 of the present invention.

[0052] Figure 26 This is a schematic diagram of the optical lens in Embodiment 6 of the present invention.

[0053] Figure 27 This is a field curvature curve diagram of the optical lens in Embodiment 6 of the present invention.

[0054] Figure 28 This is an axial aberration curve of the optical lens in Embodiment 6 of the present invention.

[0055] Figure 29 This is a chromatic aberration curve of the optical lens in Embodiment 6 of the present invention.

[0056] Figure 30 This is an MTF curve of the optical lens in Embodiment 6 of the present invention.

[0057] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0058] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of this application and are not intended to limit the scope of this 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.

[0059] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0060] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0061] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity 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 location of the concaveness 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 subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0062] It should also be understood that the terms "comprising," "including," "having," "containing," 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. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0063] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0064] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0065] The optical lens of this embodiment of the invention has eight lenses with optical power, arranged sequentially along the optical axis from the object side to the imaging plane as follows: first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens.

[0066] In some embodiments, the first lens may have negative optical power, and its object-side surface may be concave or convex, and its image-side surface may be concave or convex. The second lens may have negative optical power, and its object-side surface may be concave or convex, and its image-side surface may be concave or convex. The third lens may have negative optical power, its object-side surface is convex, and its image-side surface is concave. The fourth lens may have positive optical power, its object-side surface is convex, and its image-side surface is concave. The fifth lens may have positive optical power, its object-side surface is convex, and its image-side surface is convex. The sixth lens may have negative optical power, its object-side surface is concave, and its image-side surface is concave. The seventh lens may have positive optical power, its object-side surface is convex, and its image-side surface is convex. The eighth lens may have negative optical power, its object-side surface is concave, and its image-side surface is concave.

[0067] In some embodiments, the optical lens may further include an aperture stop, which may be located between the third and fourth lenses. It is understood that the aperture stop is used to limit the amount of light entering the lens to change the brightness of the image.

[0068] In some embodiments, the optical lens may further include a filter disposed between the eighth lens and the imaging surface. The filter is used to filter out interfering light and prevent it from reaching the imaging surface of the optical lens and affecting normal imaging.

[0069] In some embodiments, the fifth lens and the sixth lens can be cemented together to form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberrations 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.

[0070] In some embodiments, the radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 4.3 < R8 / f < 27; the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 0 < R7 / R8 < 0.25. Satisfying the above ranges can make the fourth lens have appropriate optical power and surface shape, which 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 radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: -1 < (R7 - R8) / (R7 + R8) < -0.6. Satisfying the above conditions makes the fourth lens have appropriate positive optical power, moderately converges the incident light rays at the front end, which is beneficial to correcting the aberration and distortion of the edge field of view brought by the front lens group, making the lens have less distortion and capable of providing a high-definition imaging effect.

[0072] In some embodiments, the radius of curvature R15 of the object side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -1.65 < R15 / f < -0.9. Satisfying the above conditions is beneficial to alleviating the degree of light deflection passing through the lens and can well reduce the aberration.

[0073] In some embodiments, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: 0.75 < f2 / f3 < 1.1. By reasonably setting the focal length ratio of the second lens and the third lens, the system length can be shortened, the aberration and distortion of the edge field of view can be reduced, the lens has less distortion, and can provide a high-definition imaging effect.

[0074] In some embodiments, the back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0 < BFL / TTL < 0.1. Reasonably configuring the ratio of the back focal length of the optical lens to the total optical length of the optical lens is beneficial to achieving a short back focal length of the optical lens. Under the condition of ensuring sufficient space for the installation and focusing of optical elements, it is beneficial to realize the miniaturization of the optical lens.

[0075] In some embodiments, the effective focal length f of the optical lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 50° < f×FOV / IH < 60°. Satisfying the above conditional formula, by reasonably restricting the relationship between the focal length, field angle and image height of the optical lens, it is beneficial to achieving the balance of the field angle of the optical lens and large target surface imaging, and better meets the use requirements of high image quality shooting of the optical lens.

[0076] In some embodiments, the sagittal height SAG16 of the image-side clear aperture semi-diameter, the sagittal height SAG15 of the object-side clear aperture semi-diameter of the eighth lens, and the central thickness CT8 of the eighth lens satisfy: 0.55 < (SAG16 - SAG15) / CT8 < 0.95. Meeting the above conditions, by controlling the relationship between the difference in sagittal heights of the image side and the object side of the eighth lens and the central thickness of the eighth lens, it is beneficial to correct the coma of the off-axis field of view and improve the imaging quality of the off-axis field of view of the optical lens.

[0077] In some embodiments, the clear aperture semi-diameter d1 of the object side of the first lens and the clear aperture semi-diameter d16 of the image side of the eighth lens satisfy: 1 < d1 / d16 < 1.8. By reasonably setting the ratio of the apertures of the first and last lenses, the lens can have a smaller head size while having a larger imaging surface, better meeting the balance of miniaturization and high pixels.

[0078] In some embodiments, the combined focal length f13 of the first, second, and third lenses and the combined focal length f48 of the fourth, fifth, sixth, seventh, and eighth lenses satisfy: -4.2 < f13 / f48 < -3. Meeting the above range can reasonably distribute the proportion of the optical power of the lens groups before and after the aperture stop, increase the relative illumination of the lens, and improve the imaging quality of the lens.

[0079] In some embodiments, the combined focal length f56 of the fifth and sixth lenses and the effective focal length f of the optical lens satisfy: 3.5 < f56 / f < 12. Meeting the above conditions helps more light enter the cemented lens smoothly and helps improve the illumination.

[0080] In some embodiments, the combined focal length f13 of the first, second, and third lenses and the effective focal length f of the optical lens satisfy: -3.1 < f13 / f < -1.9. Meeting the above requirements, by reasonably distributing the combined optical power of the first to third lenses, the deflection angle of the light at the front end of the lens is reduced, and the generation of various off-axis aberrations is reduced.

[0081] In some embodiments, the combined focal length f48 of the fourth, fifth, sixth, seventh, and eighth lenses and the effective focal length f of the optical lens satisfy: 0.55 < f48 / f < 0.9. Meeting the above requirements, by reasonably distributing the combined optical power of the fourth to eighth lenses, the focal length of the optical lens is balanced, the correction ability of various aberrations at the rear end of the lens is improved, and the imaging quality of the optical lens is enhanced.

[0082] In some embodiments, the sagittal height SAG4 of the image-side clear aperture radius of the second lens, the sagittal height SAG3 of the object-side clear aperture radius of the second lens, and the central thickness CT2 of the second lens satisfy: -0.2 < (SAG4 - SAG3) / CT2 < 0.25. Satisfying the above conditions can limit the degree of central depression of the second lens and reduce the difficulty of aberration correction in the peripheral field of view.

[0083] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2 < TTL / f < 3.6. Satisfying the above conditions can effectively limit the length of the lens, which is beneficial to the miniaturization of the optical lens.

[0084] In some embodiments, the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.2 < TTL / IH < 4. Satisfying the above conditions can better achieve the miniaturization of the lens. Meanwhile, when ensuring the same overall length of the lens, it has a larger image plane, can match a larger-sized imaging chip to achieve high-definition imaging.

[0085] In some embodiments, the maximum field angle FOV of the optical lens and the f-number Fno of the optical lens satisfy: 25° < FOV / Fno < 38°. Satisfying the above conditions is beneficial to increasing the light input of the lens, enabling the lens to achieve high-definition imaging even in a dim environment.

[0086] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1.1 < IH / EPD < 1.8. Satisfying the above range enables the optical lens to satisfy a large image plane while ensuring sufficient image plane brightness in the peripheral field of view, preventing the occurrence of vignetting, thereby improving the imaging quality.

[0087] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 0.8 < IH / f < 1. Satisfying the above conditions can achieve a larger field angle and imaging range, can achieve the characteristics of a large image plane while ensuring the depth of field of the optical lens, thereby improving the imaging quality of the optical system.

[0088] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.1 < BFL / f < 0.25. Satisfying the above range is beneficial to achieving a balance between obtaining good imaging quality and easy assembly. While ensuring the imaging quality of the optical lens, it avoids interference between the lens and other components, reducing the assembly process difficulty of the camera module.

[0089] In some embodiments, the total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0 < TTL / IH / FOV < 0.1 / °. Meeting the above range can achieve a balance among large image height, long focal length, and miniaturization, and improve the imaging quality of the optical lens.

[0090] In some embodiments, the total optical length TTL of the optical lens and the sum ΣCT of the central thicknesses of the first lens to the eighth lens along the optical axis satisfy: 0.55 < ΣCT / TTL < 0.8. Meeting the above conditions can effectively compress the total length of the optical lens, and is conducive to the structural design and production process of the optical lens.

[0091] In some embodiments, the clear aperture radius D1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 1 < D1 / IH / tan(FOV / 2) < 1.7. Meeting the above range can ensure the balance among the size of the optical lens, the field angle, and the image plane.

[0092] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the f-number Fno of the optical lens satisfy: 4.6 mm < IH / Fno < 8 mm. Meeting the above conditions can ensure a large aperture for the optical lens while maintaining a large image plane for the optical lens, achieving the balance between a large image plane and a large aperture.

[0093] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -10 < f1 / f < -5. Meeting the above range can allow a large range of light to enter the optical lens, obtain more picture information, and is helpful for controlling lens distortion and reducing field curvature, improving the geometric accuracy of the imaging plane.

[0094] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -10 < f2 / f < -7. Meeting the above conditions, the second lens uses a negative focal lens with a weaker refractive power, which can avoid introducing too strong light deflection, thereby better controlling other aberrations (such as spherical aberration and coma).

[0095] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -10 < f3 / f < -7. Meeting the above conditions can control the light path direction, provide a more reasonable light incident angle for the subsequent lenses, improve the relative illumination uniformity, and enhance the imaging quality.

[0096] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.2 < f4 / f < 2.2. The fourth lens that meets the above conditions can balance the optical power, control the back focal shift at high and low temperatures, and avoid defocusing.

[0097] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.6 < f5 / f < 0.9; the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -0.8 < f6 / f < -0.6. The fifth lens and the sixth lens are cemented to form a doublet lens. The fifth lens and the sixth lens can have optical powers with opposite signs, enabling sufficient correction of various aberrations of the optical lens, improving the resolution, and achieving high resolution. At the same time, the use of the cemented part helps to reduce the tolerance sensitivity of the lens to tilt / eccentricity, etc. during the assembly process, improve the resolution stability, and further enhance the system performance.

[0098] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 0.8 < f7 / f < 1.1. The seventh lens has a positive optical power, which can further focus the light, optimize the imaging quality, and correct the remaining aberrations (such as distortion, chromatic aberration, etc.), thus ensuring the imaging clarity and color reproduction.

[0099] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -0.95 < f8 / f < -0.6. Meeting the above conditions, the effective focal length value of the eighth lens is relatively small, and the light divergence effect is good. While ensuring high imaging quality, the light passing amount can be further increased.

[0100] In some embodiments, the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: -0.8 < f6 / f7 < -0.65. Meeting the above range, by reasonably setting the focal length relationship between the sixth lens and the seventh lens, the incident angle of the marginal rays can be converged, improving the illumination uniformity and clarity of the edge of the picture. At the same time, the aberrations such as distortion are finely corrected, enabling the lens picture to obtain a high-quality, dark-corner-free, and undistorted clear image.

[0101] In some embodiments, the central thickness CT4 of the fourth lens and the central thickness CT5 of the fifth lens satisfy: 0.4 < CT4 / CT5 < 0.72. Meeting the above conditions enables a reasonable configuration of the ratio of the thickness of the fourth lens on the optical axis to the thickness of the fifth lens on the optical axis, which can be mutually regulated to maintain the characteristics of miniaturization of the optical system.

[0102] In some embodiments, the central thickness CT5 of the fifth lens and the central thickness CT6 of the sixth lens satisfy: 4.2 < CT5 / CT6 < 13. Meeting the above conditions can reduce the system performance sensitivity, while ensuring the lens processing performance and assembly stability, and improving the assembly yield.

[0103] In some embodiments, the radius of curvature R15 of the object side surface of the eighth lens and the radius of curvature R16 of the image side surface of the eighth lens satisfy: -1.5 < R15 / R16 < -0.35. By satisfying the above conditions and reasonably setting the surface shape of the eighth lens, the incident light can be effectively diverged, the height of the light reaching the imaging surface can be increased, which is beneficial to achieving large target surface imaging of the lens.

[0104] In some embodiments, the radius of curvature R14 of the image side surface of the seventh lens and the radius of curvature R15 of the object side surface of the eighth lens satisfy: 0.15 < (R14 - R15) / (R14 + R15) < 0.55. By reasonably controlling the radius of curvature of the image side surface of the seventh lens and the radius of curvature of the object side surface of the eighth lens, good processability of the seventh lens and the eighth lens can be ensured.

[0105] In some embodiments, the optical lens satisfies the conditional formula: 10 mm < f < 14 mm, 28 mm < TTL < 38 mm, 1.4 < Fno < 1.9, 27° < CRA < 36°, 45° < FOV < 55°, 9 mm < IH < 12.5 mm, where f represents the effective focal length of the optical lens, TTL represents the overall optical length of the optical lens, Fno represents the aperture value of the optical lens, CRA represents the principal ray incident angle at the maximum image height of the optical lens, FOV represents the maximum field angle of the optical lens, and IH represents the image height corresponding to the maximum field angle of the optical lens. By satisfying the above conditions, it indicates that the optical lens provided by the embodiments of the present invention at least: has a long focal length characteristic, can ensure the telephoto effect of the optical lens, enables the system to have a large magnification ratio, and has good imaging quality for scenes within a relatively far field of view; has a suitable field angle and can clearly capture distant targets; has a large image surface, is adapted to a large target surface sensor, and improves the imaging quality; has a large aperture, further improves the light input of the lens, and can also ensure the clarity of the image in low light environments or at night.

[0106] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. 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.

[0107] In some embodiments, the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses can be spherical or aspherical lenses. Compared to spherical structures, aspherical structures can effectively reduce the aberrations of the optical system, thereby reducing the number of lenses and their size, and better achieving lens miniaturization. More specifically, the first and fourth lenses of this invention are spherical or aspherical lenses; the second and eighth lenses are aspherical lenses; and the third, fifth, sixth, and seventh lenses are spherical lenses.

[0108] In various embodiments of the present invention, when an aspherical lens is used, the shapes of each aspherical surface of the optical lens satisfy the following equations:

[0109]

[0110] Where 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 vertex of the surface, K is the quadratic surface coefficient, and B, C, D, E, F, G, and H are the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth order surface coefficients, respectively.

[0111] The present invention will be further described below with reference to several 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 tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

[0112] Example 1

[0113] Please see Figure 1 The figure shown is a schematic diagram of the structure of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 includes, along the optical axis from the object side to the imaging plane, the following components in sequence: a first lens L1, a second lens L2, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0114] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0115] The second lens L2 has negative optical power, its object side S3 is concave, and its image side S4 is convex.

[0116] The third lens L3 has negative optical power, its object side S5 is convex, and its image side S6 is concave.

[0117] The fourth lens L4 has positive optical power, with its object-side surface S7 being convex and its image-side surface S8 being concave.

[0118] The fifth lens L5 has positive optical power, its object side S9 is convex, and its image side is convex.

[0119] The sixth lens L6 has negative optical power, its object side is concave, and its image side S11 is concave.

[0120] The fifth lens L5 and the sixth lens L6 form a cemented lens group with positive optical power, that is, the cemented surface of the image side of the fifth lens L5 and the object side of the sixth lens L6 is S10.

[0121] The seventh lens L7 has positive optical power, its object side surface S12 is convex, and its image side surface S13 is convex.

[0122] The eighth lens L8 has negative optical power, its object side S14 is concave, and its image side S15 is concave.

[0123] The object-side surface S16 and the image-side surface S17 of filter G1 are both planar.

[0124] The imaging plane S18 is a plane.

[0125] The first, third, fifth, sixth, and seventh lenses are glass spherical lenses, while the second, fourth, and eighth lenses are glass aspherical lenses.

[0126] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0127] Table 1-1

[0128]

[0129] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0130] Table 1-2

[0131] Face number K B C D E F G H S3 -5.05E+00 -1.24E-06 -9.63E-07 -1.32E-07 4.86E-09 -5.27E-11 0.00E+00 0.00E+00 S4 -9.74E+00 7.24E-05 -1.75E-06 -1.14E-07 4.35E-09 -4.65E-11 0.00E+00 0.00E+00 S7 1.64E+00 3.35E-04 -1.29E-05 5.07E-07 -1.49E-08 3.82E-10 0.00E+00 0.00E+00 S8 4.84E+03 4.40E-04 -2.22E-06 1.19E-06 -6.27E-08 1.95E-09 0.00E+00 0.00E+00 S14 -1.34E-01 -2.64E-03 2.05E-05 1.37E-06 -4.44E-08 3.60E-10 0.00E+00 0.00E+00 S15 3.73E+00 -1.78E-03 4.39E-05 -1.52E-06 3.67E-08 -4.30E-10 0.00E+00 0.00E+00

[0132] In this embodiment, the field curvature curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown.

[0133] Figure 2The field curvature curve of Example 1 is shown, which represents the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within -0.04 mm to 0.02 mm, indicating that the optical lens can effectively correct the field curvature.

[0134] Figure 3 The axial aberration curve of Example 1 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the axial aberration offset is controlled within -0.02 mm to 0.01 mm, indicating that the optical lens can correct axial aberration well.

[0135] Figure 4 The diagram shows the transverse chromatic aberration curves for Example 1, representing the chromatic aberration of each wavelength relative to the center wavelength (0.546 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the diagram, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±1 μm, indicating that the optical lens can effectively correct chromatic aberration.

[0136] Figure 5 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in various fields of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents MTF value. As can be seen from the figure, the MTF value of this example is above 0.48 throughout the entire field of view. Within the range of 0–120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies.

[0137] Example 2

[0138] Please see Figure 6 The figure shows a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The optical lens in this embodiment is roughly the same as that in Embodiment 1. The main difference is that the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0139] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0140] Table 2-1

[0141]

[0142]

[0143] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0144] Table 2-2

[0145] Face number K B C D E F G H S3 -2.11E+00 -3.38E-04 6.65E-06 2.77E-08 -7.74E-09 1.47E-10 2.33E-12 -6.94E-14 S4 -1.82E+00 -6.06E-05 4.06E-06 -7.44E-08 -1.54E-09 4.39E-11 6.60E-13 -1.86E-14 S7 9.59E-01 2.15E-04 8.87E-06 -3.62E-08 -7.34E-10 1.45E-10 -2.70E-12 1.41E-13 S8 1.04E+02 4.45E-04 1.11E-05 4.16E-07 -9.67E-09 3.52E-10 -3.32E-12 7.04E-13 S14 2.74E+00 -1.74E-03 5.44E-05 2.89E-07 -3.02E-08 -3.98E-10 5.64E-11 -2.10E-13 S15 -5.13E+01 -1.23E-03 2.63E-05 1.84E-06 -8.04E-08 -2.48E-10 9.15E-11 -9.79E-13

[0146] In this embodiment, the field curvature curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 200 are respectively as follows: Figure 7 , Figure 8 , Figure 9 , Figure 10 As shown.

[0147] from Figure 7 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.02mm, indicating that the optical lens can effectively correct the field curvature.

[0148] from Figure 8 As can be seen, the axial aberration offset is controlled within -0.03mm to 0.01mm, indicating that the optical lens can effectively correct axial aberration.

[0149] from Figure 9 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±2μm, indicating that the optical lens can effectively correct chromatic aberration.

[0150] from Figure 10 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions.

[0151] Example 3

[0152] Please see Figure 11 The figure shows a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The optical lens of this embodiment is roughly the same as that of Embodiment 1. The main difference is that the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0153] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0154] Table 3-1

[0155]

[0156] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0157] Table 3-2

[0158] Face number K B C D E F G H S3 -4.84E+00 1.81E-07 -7.80E-07 -1.34E-07 4.77E-09 -5.62E-11 0.00E+00 0.00E+00 S4 -8.79E+00 6.73E-05 -1.38E-06 -1.13E-07 4.04E-09 -4.66E-11 0.00E+00 0.00E+00 S7 1.61E+00 3.24E-04 -1.27E-05 5.30E-07 -1.45E-08 3.61E-10 0.00E+00 0.00E+00 S8 4.78E+03 4.42E-04 -3.37E-06 1.24E-06 -5.85E-08 1.73E-09 0.00E+00 0.00E+00 S14 -5.16E+00 -2.53E-03 2.92E-05 1.15E-06 -4.31E-08 4.52E-10 0.00E+00 0.00E+00 S15 6.13E+00 -1.71E-03 4.52E-05 -1.51E-06 3.36E-08 -3.76E-10 0.00E+00 0.00E+00

[0159] In this embodiment, the field curvature curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 300 are respectively as follows: Figure 12 , Figure 13 , Figure 14 , Figure 15 As shown.

[0160] from Figure 12 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.04mm to 0.02mm, indicating that the optical lens can effectively correct the field curvature.

[0161] from Figure 13 As can be seen, the axial aberration offset is controlled within -0.03mm to 0.01mm, indicating that the optical lens can effectively correct axial aberration.

[0162] from Figure 14 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±1μm, indicating that the optical lens can effectively correct chromatic aberration.

[0163] from Figure 15 As can be seen, the MTF value of this embodiment is above 0.58 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0164] Example 4

[0165] Please see Figure 16 The diagram shows a schematic of the structure of the optical lens 400 provided in Embodiment 4 of the present invention. The optical lens in this embodiment is generally the same as that in Embodiment 1, except that: the object-side surface S1 of the first lens L1 is concave; the image-side surface S2 of the first lens L2 is convex; the object-side surface S3 of the second lens L2 is convex; the image-side surface S4 of the second lens L2 is concave; the first lens L1 is a glass aspherical lens; the fourth lens L4 is a glass spherical lens; and the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0166] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0167] Table 4-1

[0168]

[0169] The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0170] Table 4-2

[0171] Face number K B C D E F G H S1 -2.99E+00 4.35E-04 1.81E-07 -1.38E-07 8.87E-10 7.18E-12 -2.99E+00 4.35E-04 S2 -1.16E+01 4.33E-04 5.85E-06 -5.64E-08 -8.24E-09 1.27E-10 -1.16E+01 4.33E-04 S3 1.38E+00 2.52E-04 4.17E-06 7.94E-08 -7.25E-09 7.27E-11 1.38E+00 2.52E-04 S4 -5.64E+00 2.88E-04 3.35E-05 -1.24E-06 4.90E-08 -9.76E-10 -5.64E+00 2.88E-04 S14 -1.32E+01 -3.55E-03 5.24E-05 -1.04E-06 5.53E-08 -1.18E-09 -1.32E+01 -3.55E-03 S15 -1.37E+01 -1.48E-03 4.37E-05 -1.09E-06 1.52E-08 -1.40E-10 -1.37E+01 -1.48E-03

[0172] In this embodiment, the field curvature curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 400 are respectively as follows: Figure 17 , Figure 18 , Figure 19 , Figure 20 As shown.

[0173] from Figure 17 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.02mm to 0.04mm, indicating that the optical lens can effectively correct the field curvature.

[0174] from Figure 18 As can be seen, the axial aberration offset is controlled within -0.02mm to 0.03mm, indicating that the optical lens can effectively correct axial aberration.

[0175] from Figure 19 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -1μm to 2μm, indicating that the optical lens can correct chromatic aberration well.

[0176] from Figure 20 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions.

[0177] Example 5

[0178] Please see Figure 21 The diagram shows a schematic of the structure of the optical lens 500 provided in Embodiment 5 of the present invention. The optical lens in this embodiment is generally the same as that in Embodiment 1, except that: the object-side surface S1 of the first lens L1 is concave; the image-side surface S2 of the first lens L2 is convex; the object-side surface S3 of the second lens L2 is convex; the image-side surface S4 of the second lens L2 is concave; the first lens L1 is a glass aspherical lens; the fourth lens L4 is a glass spherical lens; and the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0179] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0180] Table 5-1

[0181]

[0182]

[0183] The surface profile parameters of the aspherical lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0184] Table 5-2

[0185] Face number K B C D E F G H S1 -3.08E+00 4.49E-04 3.21E-07 -1.37E-07 8.10E-10 8.82E-12 0.00E+00 0.00E+00 S2 -1.23E+01 4.49E-04 5.88E-06 -5.84E-08 -7.85E-09 1.23E-10 0.00E+00 0.00E+00 S3 1.36E+00 2.52E-04 3.92E-06 8.12E-08 -6.88E-09 7.13E-11 0.00E+00 0.00E+00 S4 -5.61E+00 2.70E-04 3.29E-05 -1.21E-06 4.44E-08 -8.24E-10 0.00E+00 0.00E+00 S14 -1.43E+01 -3.18E-03 5.41E-05 -1.31E-06 4.95E-08 -8.97E-10 0.00E+00 0.00E+00 S15 -3.35E+00 -1.35E-03 3.47E-05 -8.68E-07 1.85E-08 -2.05E-10 0.00E+00 0.00E+00

[0186] In this embodiment, the field curvature curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 500 are respectively as follows: Figure 22 , Figure 23 , Figure 24 , Figure 25 As shown.

[0187] from Figure 22 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.02mm, indicating that the optical lens can effectively correct the field curvature.

[0188] from Figure 23 As can be seen, the axial aberration offset is controlled within -0.01mm to 0.02mm, indicating that the optical lens can effectively correct axial aberration.

[0189] from Figure 24 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±1μm, indicating that the optical lens can effectively correct chromatic aberration.

[0190] from Figure 25 As can be seen, the MTF value of this embodiment is above 0.5 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0191] Example 6

[0192] Please see Figure 26 The diagram shows a schematic of the structure of the optical lens 600 provided in Embodiment 6 of the present invention. The optical lens in this embodiment is generally the same as that in Embodiment 1, except that: the object-side surface S1 of the first lens L1 is concave; the image-side surface S2 of the first lens L2 is convex; the object-side surface S3 of the second lens L2 is convex; the image-side surface S4 of the second lens L2 is concave; the first lens L1 is a glass aspherical lens; the fourth lens L4 is a glass spherical lens; and the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0193] The relevant parameters of each lens in the optical lens 600 in Example 6 are shown in Table 6-1.

[0194] Table 6-1

[0195]

[0196] The surface profile parameters of the aspherical lens of the optical lens 600 in Example 6 are shown in Table 6-2.

[0197] Table 6-2

[0198]

[0199]

[0200] In this embodiment, the field curvature curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 600 are respectively as follows: Figure 27 , Figure 28 , Figure 29 , Figure 30 As shown.

[0201] from Figure 27 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.02mm, indicating that the optical lens can effectively correct the field curvature.

[0202] from Figure 28 As can be seen, the axial aberration offset is controlled within -0.02mm to 0.01mm, indicating that the optical lens can effectively correct axial aberration.

[0203] from Figure 29 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±2μm, indicating that the optical lens can effectively correct chromatic aberration.

[0204] from Figure 30 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions.

[0205] Please refer to Table 7 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, true image height IH corresponding to the maximum field of view, principal ray incident angle CRA at the maximum image height, maximum field of view FOV, and the values ​​corresponding to each conditional expression in each embodiment.

[0206] Table 10

[0207]

[0208]

[0209] In summary, the optical lens provided by the present invention employs eight lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as large aperture, long focal length, high pixel count, and high imaging quality.

[0210] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0211] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An optical lens comprising eight lenses having optical power, characterized in that, It successively includes from the object side to the imaging surface along the optical axis: A first lens with a negative optical power; A second lens with a negative optical power; A third lens with a negative optical power, whose object side is convex and whose image side is concave; A fourth lens with a positive optical power, whose object side is convex and whose image side is concave; A fifth lens with a positive optical power, whose object side is convex and whose image side is convex; A sixth lens with a negative optical power, whose object side is concave and whose image side is concave; A seventh lens with a positive optical power, whose object side is convex and whose image side is convex; An eighth lens with a negative optical power, whose object side is concave and whose image side is concave; Wherein, the radius of curvature R8 of the image side of the fourth lens and the effective focal length f of the optical lens satisfy: 4.3 < R8 / f < 27; the radius of curvature R7 of the object side of the fourth lens and the radius of curvature R8 of the image side of the fourth lens satisfy: 0 < R7 / R8 < 0.

25.

2. The optical lens according to claim 1, characterized in that, The radius of curvature R7 of the object side of the fourth lens and the radius of curvature R8 of the image side of the fourth lens satisfy: -1 < (R7 - R8) / (R7 + R8) < -0.

6.

3. The optical lens according to claim 1, characterized in that, The radius of curvature R15 of the object side of the eighth lens and the effective focal length f of the optical lens satisfy: -1.65 < R15 / f < -0.

9.

4. The optical lens according to claim 1, characterized in that, The focal length f2 of the second lens and the focal length f3 of the third lens satisfy: 0.75 < f2 / f3 < 1.

1.

5. The optical lens according to claim 1, characterized in that, The back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0 < BFL / TTL < 0.

1.

6. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens, the true image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 50° < f×FOV / IH < 60°.

7. The optical lens according to claim 1, characterized in that, The sagittal height SAG16 of the image side clear aperture semi-diameter of the eighth lens, the sagittal height SAG15 of the object side clear aperture semi-diameter of the eighth lens and the central thickness CT8 of the eighth lens satisfy: 0.55 < (SAG16 - SAG15) / CT8 < 0.

95.

8. The optical lens according to claim 1, characterized in that, The clear aperture semi-diameter d1 of the object side of the first lens and the clear aperture semi-diameter d16 of the image side of the eighth lens satisfy: 1 < d1 / d16 < 1.

8.

9. The optical lens according to claim 1, characterized in that, The combined focal length f13 of the first lens, the second lens and the third lens and the combined focal length f48 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -4.2 < f13 / f48 < -3.

10. 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 effective focal length f of the optical lens satisfy: 3.5 < f56 / f < 12.

Images