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 convex surface, and the image side surface of the second lens is a concave surface; the object side surface of the third lens is a 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 convex surface; the object side surface of the fifth lens is a concave 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, in particular to an optical lens. BACKGROUND

[0002] With the continuous improvement of people's requirements for driving experience, vehicle application type optical lenses are used more and more in intelligent driving, and vehicle optical lenses are constantly improving in the automobile industry.

[0003] Advanced Driver Assistance System (ADAS) plays an important role in intelligent driving, which collects environmental information through various lenses and sensors to ensure the safety of drivers. In addition to the requirements of light, thin, small shape and high pixel, high resolution of the existing ADAS system lens, the optical lens is required to be able 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 the advantages of 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] The first lens with negative optical power has a concave object side and a convex image side;

[0008] The second lens with negative optical power has a convex object side and a concave image side;

[0009] The third lens with negative optical power has a convex object side and a concave image side;

[0010] The fourth lens with positive optical power has a convex object side and a convex image side;

[0011] The fifth lens with positive optical power has a concave object side and a convex image side;

[0012] The sixth lens with negative optical power has a concave object side and a concave image side;

[0013] The seventh lens with positive optical power has a convex object side and a convex image side;

[0014] The eighth lens with negative optical power has a concave object side and a concave image side;

[0015] Wherein, the object-side radius of curvature R9 of the fifth lens and the image-side radius of curvature R10 of the fifth lens satisfy: 7.2 <R9 / R10<16。

[0016] Further preferably, the radius of curvature R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -1 <R1 / f<-0.8。

[0017] Further preferably, the radius of curvature R9 of the object-side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -9.5 <R9 / f<-4。

[0018] Further preferably, the center thickness CT1 of the first lens and the center thickness CT2 of the second lens satisfy: 2 <CT1 / CT2<2.6。

[0019] Further preferably, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.9 <f1 / f2<1.1。

[0020] Further preferably, the total optical length TTL of the optical lens satisfies the following condition: 2.8 <TTL / IH<3.2。

[0021] Further preferably, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.15 <BFL / f<0.25。

[0022] Further preferably, the effective focal length f 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: 50° <f×FOV / IH<60°。

[0023] Further preferably, the true image height IH corresponding to the maximum field of view of the optical lens and the aperture value Fno of the optical lens satisfy: 4.5mm <IH / Fno<6.8mm。

[0024] Further preferably, the image-side half-aperture height SAG2 of the first lens, the object-side half-aperture height SAG1 of the first lens, and the center thickness CT1 of the first lens satisfy: 0.1 < (SAG2 - SAG1) / CT1 < 0.2.

[0025] The optical lens provided by this invention uses 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. Attached Figure Description

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

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

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

[0029] Figure 3 This is an axial aberration curve of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 4 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 5 This is an MTF curve of the optical lens in Embodiment 1 of the present invention.

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

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

[0034] Figure 8 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0035] Figure 9 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0036] Figure 10 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

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

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

[0039] Figure 13 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

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

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] In some embodiments, the first lens may have negative optical power, with a concave object-side surface and a convex image-side surface. The second lens may have negative optical power, with a convex object-side surface and a concave image-side surface. The third lens may have negative optical power, with a convex object-side surface and a concave image-side surface. The fourth lens may have positive optical power, with a convex object-side surface and a convex image-side surface. The fifth lens may have positive optical power, with a concave object-side surface and a convex image-side surface. The sixth lens may have negative optical power, with a concave object-side surface and a concave image-side surface. The seventh lens may have positive optical power, with a convex object-side surface and a convex image-side surface. The eighth lens may have negative optical power, with a concave object-side surface and a concave image-side surface.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] In some embodiments, the radius of curvature R9 of the object side surface of the fifth lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: 7.2 < R9 / R10 < 16. The surface shape of the fifth lens that meets the above conditions can balance the aberration generated by the front group of lenses and avoid deterioration of the edge image quality.

[0056] In some embodiments, the radius of curvature R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -1 < R1 / f < -0.8; the radius of curvature R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: -1.3 < R2 / f < -1.1. The first lens is a meniscus negative lens. By reasonably configuring the ratio of the radius of curvature of the object side surface and the image side surface of the first lens to the effective focal length of the optical lens, the first lens can collect as much light as possible with a large field angle and make the light enter the subsequent system smoothly, increasing the light passing amount of the optical lens and effectively expanding the field angle range of the optical lens.

[0057] In some embodiments, the radius of curvature R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -9.5 < R9 / f < -4. Meeting the above conditions, the fifth lens can cooperate with the negative lens in the front group to better correct chromatic aberration. In addition, the fifth lens can also reduce the height and angle of the light entering the subsequent lens.

[0058] In some embodiments, the central thickness CT1 of the first lens and the central thickness CT2 of the second lens satisfy: 2 < CT1 / CT2 < 2.6. Reasonably configuring the ratio of the thickness of the first lens on the optical axis to the thickness of the second lens on the optical axis can enable mutual regulation and maintain the characteristic of miniaturization of the optical system.

[0059] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.9 < f1 / f2 < 1.1. By reasonably setting the focal length ratio of the first lens and the second lens, the system length can be shortened, the aberration and distortion of the edge field can be reduced, the lens has less distortion, and a high-definition imaging effect can be provided.

[0060] In some embodiments, the overall optical length TTL of the optical lens and the overall optical length TTL of the optical lens satisfy: 2.8 < TTL / IH < 3.2. It can better achieve the miniaturization of the lens. At the same time, when ensuring the same overall length of the lens, it has a larger image plane and can match a larger-sized imaging chip to achieve high-definition imaging.

[0061] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.15 < BFL / f < 0.25. Meeting the above range is beneficial to achieving a balance between obtaining good imaging quality and easy assembly, ensuring the imaging quality of the optical lens while avoiding interference between the lens and other components and reducing the assembly process difficulty of the camera module.

[0062] 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°. Meeting the above conditional formula is beneficial to achieving the balance between the field angle of the optical lens and large target surface imaging by reasonably restricting the relationship between the focal length, field angle, and image height of the optical lens, and better meeting the usage requirements of high image quality shooting of the optical lens.

[0063] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 4.5mm < IH / Fno < 6.8mm. Meeting the above conditions can ensure that the optical lens has a large aperture while maintaining a large image plane of the optical lens, achieving the balance between a large image plane and a large aperture.

[0064] In some embodiments, the sagittal height SAG2 of the image side clear aperture radius, the sagittal height SAG1 of the object side clear aperture radius of the first lens, and the central thickness CT1 of the first lens satisfy: 0.1 < (SAG2 - SAG1) / CT1 < 0.2. Meeting the above conditions can limit the central depression degree of the first lens and reduce the difficulty of off-axis aberration correction in the marginal field.

[0065] In some embodiments, 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 < 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, increase the relative illumination of the lens, and improve the imaging quality of the lens.

[0066] In some embodiments, the combined focal length f13 of the first lens, the second lens, and the third lens and the effective focal length f of the optical lens satisfy: -3 < f13 / f < -2.3. Meeting the above requirements can reduce the light deflection angle at the front end of the lens and reduce the generation of various off-axis aberrations by reasonably distributing the combined optical power of the first lens to the third lens.

[0067] In some embodiments, the combined focal length f48 of the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens and the effective focal length f of the optical lens satisfy: 0.65 < f48 / f < 0.8. Meeting the above requirements, by reasonably distributing the combined optical power of the fourth lens to the eighth lens, 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.

[0068] In some embodiments, the combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: -1.7 < f56 / f < -1.2. Meeting the above conditions helps more light enter the cemented lens smoothly and helps improve the illuminance.

[0069] 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: 1.15 < d1 / d16 < 1.45. 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, which can better meet the balance of miniaturization and high pixels.

[0070] In some embodiments, the sagittal height SAG4 of the clear aperture semi-diameter of the image side of the second lens, the sagittal height SAG3 of the clear aperture semi-diameter of the object side of the second lens, and the central thickness CT2 of the second lens satisfy: 0 < (SAG4 - SAG3) / CT2 < 0.1. Meeting 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.

[0071] In some embodiments, the sagittal height SAG16 of the clear aperture semi-diameter of the image side of the eighth lens, the sagittal height SAG15 of the clear aperture semi-diameter of the object side of the eighth lens, and the central thickness CT8 of the eighth lens satisfy: 0.8 < (SAG16 - SAG15) / CT8 < 1.1. Meeting the above conditions, by controlling the relationship between the difference in sagittal height between 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 in the off-axis field of view and improve the imaging quality of the off-axis field of view of the optical lens.

[0072] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.3 < TTL / f < 3. Meeting the above conditions can effectively limit the length of the lens and is beneficial to the miniaturization of the optical lens.

[0073] In some embodiments, the maximum field of view FOV of the optical lens and the f-number Fno of the optical lens satisfy: 25° < FOV / Fno < 35°. Meeting the above conditions is beneficial to increasing the light input of the lens and enabling the lens to achieve high-definition imaging in a dim environment.

[0074] 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: 1.3 < IH / EPD < 1.7. Meeting the above range enables the optical lens to satisfy a large image plane while also ensuring sufficient image plane brightness in the peripheral field of view, preventing vignetting, and thus improving the imaging quality.

[0075] 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 < 0.95. Meeting the above conditions can achieve a larger field angle and imaging range, and can achieve the characteristics of a large image plane while ensuring the depth of field of the optical lens, thus improving the imaging quality of the optical system.

[0076] In some embodiments, the overall 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.

[0077] In some embodiments, the overall 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: 0.65 < ΣCT / TTL < 0.8. Meeting the above conditions can effectively compress the overall length of the optical lens, and is conducive to the structural design and production process of the optical lens.

[0078] 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: 1.1 < D1 / IH / tan(FOV / 2) < 1.4. Meeting the above range can ensure the balance among the size, field angle, and image plane of the optical lens.

[0079] In some embodiments, the back focal length BFL of the optical lens and the overall 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 overall optical length of the optical lens is conducive to achieving a short back focus of the optical lens, and is conducive to the miniaturization of the optical lens while ensuring sufficient space for the installation and focusing of optical elements.

[0080] 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 < -8. 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, and improving the geometric accuracy of the imaging plane.

[0081] 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 < -8. Meeting the above conditions, the second lens uses a negative focal lens with a relatively weak refractive power, which can avoid introducing too strong light deflection, thereby better controlling other aberrations (such as spherical aberration and coma).

[0082] 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 < -8. 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.

[0083] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 0.8 < f4 / f < 1. The fourth lens meeting the above conditions can balance the optical power, control the back focus shift at high and low temperatures, and avoid defocusing.

[0084] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.9 < f5 / f < 1.1; the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -0.7 < f6 / f < -0.55. The fifth lens and the sixth lens are glued to form a doublet lens. The fifth lens and the sixth lens can have opposite optical powers, so that various aberrations of the optical lens are fully corrected, the resolution can be improved, and high resolution can be achieved. At the same time, the use of the glued part is beneficial to reducing the tolerance sensitivity of the lens to tilt / eccentricity, etc. during the assembly process, improving the resolution stability, and further enhancing the system performance.

[0085] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 0.7 < f7 / f < 0.95. The seventh lens uses 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.), thereby ensuring the imaging clarity and color reproduction.

[0086] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -0.8 < 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, which can further increase the light transmission while ensuring high imaging quality.

[0087] In some embodiments, the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: -12 < f3 / f4 < -9. Meeting the above conditions, by reasonably setting the focal lengths of the third and fourth lenses, the convergence of light can be better achieved, the distance for light to enter the next lens can be shortened, which is beneficial to the miniaturization of the optical lens.

[0088] In some embodiments, the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -1.35 < f7 / f8 < -1.1. By reasonably setting the focal length ratio 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.

[0089] In some embodiments, the central thickness CT7 of the seventh lens and the central thickness CT8 of the eighth lens satisfy: 2.2 < CT7 / CT8 < 3.8. Meeting the above conditions can reduce the sensitivity of system performance, while ensuring the lens processing performance and assembly stability, and improving the assembly yield rate.

[0090] In some embodiments, the curvature radius R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 0.85 < R7 / f < 1.2. Meeting the above range can make the fourth lens have an appropriate 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.

[0091] In some embodiments, the curvature radius R15 of the object side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -1.5 < R15 / f < -0.8. Meeting the above conditions is beneficial to alleviating the degree of light deflection passing through the lens and can effectively reduce aberration.

[0092] In some embodiments, the curvature radius R15 of the object side surface of the eighth lens and the curvature radius R16 of the image side surface of the eighth lens satisfy: -1.3 < R15 / R16 < -0.65. Meeting the above conditions, by reasonably setting the surface shape of the eighth lens, the incident light can be effectively diverged, increasing the height of the light reaching the imaging surface, which is beneficial to achieving large target surface imaging of the lens.

[0093] In some embodiments, the curvature radius R9 of the object side surface of the fifth lens and the curvature radius R10 of the image side surface of the fifth lens satisfy: 0.7 < (R9 - R10) / (R9 + R10) < 0.95. By making the optical system satisfy the above relational expression, it is beneficial to reasonably configure the ratio of the curvature radii of the object side surface and the image side surface of the fifth lens, control the shape of the fifth lens, comprehensively balance the spherical aberration, chromatic aberration and field curvature of the optical system, reduce the risk of ghosting, improve the resolution ability of the optical system, and at the same time, it is also beneficial to reducing the processing difficulty of the fifth lens.

[0094] In some embodiments, the curvature radius R15 of the object side surface of the eighth lens and the curvature radius R16 of the image side surface of the eighth lens satisfy: -6.5 < (R15 - R16) / (R15 + R16) < -16. Meeting the above range is beneficial to suppressing the angle of the marginal field of view incident on the imaging surface, effectively transmitting more light beams to the imaging surface, and at the same time balancing the field curvature and spherical aberration of the optical lens, improving the imaging quality of the optical lens.

[0095] In some embodiments, the optical lens satisfies the conditional formula: 10mm < f < 12mm, 28mm < TTL < 31mm, 1.5 < Fno < 1.9, 28° < CRA < 32°, 45° < FOV < 55°, 9mm < IH < 10.5mm, 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. Meeting the above conditions 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, enable the system to have a large magnification ratio, and have 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 plane, 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 ensure the clarity of the image even in low light environments or at night.

[0096] In some embodiments, the lens material of the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. 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.

[0097] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the first lens, the second lens, and the eighth lens of the present invention adopt aspherical lenses; the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens adopt spherical lenses.

[0098] In various embodiments of the present invention, when the lens adopts an aspherical lens, the surface shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0099]

[0100] where z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the conic coefficient, and B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients respectively.

[0101] 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.

[0102] Example 1

[0103] 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.

[0104] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is convex.

[0105] The second lens L2 has negative optical power, its object side S3 is convex, and its image side S4 is concave.

[0106] The third lens L3 has negative optical power, its object side S5 is convex, and its image side S6 is concave.

[0107] The fourth lens L4 has positive optical power, and its object side S7 is convex, and its image side S8 is convex.

[0108] The fifth lens L5 has positive optical power, its object side S9 is concave, and its image side is convex.

[0109] The sixth lens L6 has negative optical power, its object side is concave, and its image side S11 is concave.

[0110] The fifth lens L5 and the sixth lens L6 form a cemented lens group with negative 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.

[0111] The seventh lens L7 has positive optical power, its object side S12 is convex, and its image side S13 is convex.

[0112] The eighth lens L8 has negative optical power, its object side S14 is concave, and its image side S15 is concave.

[0113] The object-side surface S16 and the image-side surface S17 of filter G1 are both planar.

[0114] The imaging plane S18 is a plane.

[0115] The third, fourth, fifth, sixth, and seventh lenses are glass spherical lenses, while the first, second, and eighth lenses are glass aspherical lenses.

[0116] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0117] Table 1-1

[0118]

[0119] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0120] Table 1-2

[0121] Figure 2 K B C D E F S1 -5.46E+00 3.36E-04 -2.77E-06 9.31E-08 -2.05E-09 1.57E-11 S2 -1.54E+01 3.89E-04 6.22E-06 1.54E-07 5.73E-11 1.15E-11 S3 -1.07E+01 -1.43E-04 -2.94E-06 7.26E-07 -1.30E-08 -2.41E-11 S4 -1.51E+01 -1.20E-04 7.84E-06 2.70E-07 -1.95E-09 -1.15E-10 S14 9.44E+00 -2.84E-03 1.26E-04 -3.33E-06 5.61E-08 1.15E-09 S15 -3.61E+00 -2.72E-03 1.37E-04 -6.04E-06 1.80E-07 -2.38E-09

[0122] 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 3 , Figure 4 , Figure 5 , Figure 2 As shown.

[0123] Figure 3 The 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.

[0124] Figure 4 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 -0.03 mm to 0.02 mm, indicating that the optical lens can correct axial aberration well.

[0125] Figure 5 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.

[0126] Figure 6 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.

[0127] Example 2

[0128] Please see Figure 7 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.

[0129] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0130] Table 2-1

[0131]

[0132]

[0133] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0134] Table 2-2

[0135] Figure 8 K B C D E F S1 -4.11E+00 3.79E-04 -2.63E-06 9.13E-08 -2.21E-09 1.52E-11 S2 -1.07E+01 3.47E-04 1.11E-05 1.07E-07 -2.27E-09 2.17E-10 S3 -1.97E+01 -2.78E-04 -4.00E-06 1.08E-06 -2.98E-08 3.94E-10 S4 -1.71E+01 -3.01E-04 6.15E-06 7.98E-07 -1.52E-08 2.09E-11 S14 4.61E+00 -3.62E-03 2.27E-04 -3.48E-06 -1.30E-07 1.56E-08 S15 -2.04E+01 -2.71E-03 1.78E-04 -7.10E-06 1.63E-07 -9.81E-10

[0136] 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 9 , Figure 10 , Figure 7 , Figure 8 As shown.

[0137] from Figure 9 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.

[0138] from Figure 10 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.

[0139] from Figure 11As 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.

[0140] from Figure 12 As can be seen, the MTF value of this embodiment is above 0.48 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.

[0141] Example 3

[0142] Please see Figure 13 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.

[0143] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0144] Table 3-1

[0145]

[0146] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0147] Table 3-2

[0148] Figure 14 K B C D E F S1 -3.86E+00 3.46E-04 -3.30E-06 1.21E-07 -1.94E-09 4.67E-12 S2 -7.63E+00 2.60E-04 8.15E-06 -4.00E-08 3.96E-09 1.59E-12 S3 -2.02E+01 -3.28E-04 -7.59E-06 1.12E-06 -3.17E-08 3.83E-10 S4 -1.33E+01 -3.14E-04 4.70E-06 9.21E-07 -3.06E-08 4.61E-10 S14 3.93E+00 -3.19E-03 1.87E-04 -2.81E-06 -7.46E-08 8.08E-09 S15 -2.46E+00 -3.14E-03 1.76E-04 -6.40E-06 1.38E-07 -9.42E-10

[0149] 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 15 , Figure 12 , Figure 13 , Figure 14 As shown.

[0150] from Figure 15 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.

[0151] from ​ 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.

[0152] from ​ 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.

[0153] from ​ 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.

[0154] Please refer to Table 4 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.

[0155] Table 4

[0156]

[0157]

[0158] 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.

[0159] 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.

[0160] 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 sequentially includes, from the object side to the imaging surface along the optical axis: A first lens with a negative optical power, whose object side is concave and whose image side is convex; A second lens with a negative optical power, whose object side is convex and whose image side is concave; A third lens with a negative optical power, whose object side is 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 convex; A fifth lens with a positive optical power, whose object side is concave 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 curvature radius R9 of the object side of the fifth lens and the curvature radius R10 of the image side of the fifth lens satisfy: 7.2 < R9 / R10 < 16.

2. The optical lens according to claim 1, characterized in that, The curvature radius R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: -1 < R1 / f < -0.8; the curvature radius R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: -1.3 < R2 / f < -1.

1.

3. The optical lens according to claim 1, characterized in that, The curvature radius R9 of the object side of the fifth lens and the effective focal length f of the optical lens satisfy: -9.5 < R9 / f < -4.

4. The optical lens according to claim 1, characterized in that, The central thickness CT1 of the first lens and the central thickness CT2 of the second lens satisfy: 2 < CT1 / CT2 < 2.

6.

5. The optical lens according to claim 1, characterized in that, The focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.9 < f1 / f2 < 1.

1.

6. The optical lens according to claim 1, characterized in that, The overall optical length TTL of the optical lens and the overall optical length TTL of the optical lens satisfy: 2.8 < TTL / IH < 3.

2.

7. The optical lens according to claim 1, characterized in that, The back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.15 < BFL / f < 0.

25.

8. 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°.

9. The optical lens according to claim 1, characterized in that, The true image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 4.5mm < IH / Fno < 6.8mm.

10. The optical lens according to claim 1, characterized in that, The sagittal height SAG2 of the clear aperture semi-diameter of the image side of the first lens, the sagittal height SAG1 of the clear aperture semi-diameter of the object side of the first lens, and the central thickness CT1 of the first lens satisfy: 0.1 < (SAG2 - SAG1) / CT1 < 0.2.

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