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 positive focal power, a third lens with negative focal power, a fourth lens with negative focal power and a fifth 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 convex surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the fourth lens has negative focal power, and the object 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 convex 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 vehicle optical lenses are playing an increasingly important role in the automotive industry.

[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 optical lenses for the existing ADAS system, such as light, thin, small shape and high pixel, high resolution, the optical lens is also 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, a total of eight lenses, including in order along the optical axis from the object side to the imaging surface:

[0007] The first lens with negative focal power, the object side surface is concave;

[0008] The second lens with positive focal power, the object side surface is convex, and the image side surface is convex;

[0009] The third lens with positive focal power, the object side surface is convex, and the image side surface is convex;

[0010] The fourth lens with negative focal power, the object side surface is concave;

[0011] The fifth lens with positive focal power, the object side surface is convex, and the image side surface is convex;

[0012] The sixth lens with negative focal power, the object side surface is concave, and the image side surface is concave;

[0013] The seventh lens with positive focal power, the object side surface is convex, and the image side surface is convex;

[0014] The eighth lens with negative focal power, the object side surface is concave, and the image side surface is convex;

[0015] The image-side surface curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: 0.5 < R12 / f < 0.9.

[0016] Further preferably, the object-side surface curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: -0.5 < R15 / f < -0.4; and the image-side surface curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: -4.8 < R16 / f < -3.2.

[0017] Further preferably, the object-side surface curvature radius R11 of the sixth lens and the image-side surface curvature radius R12 of the sixth lens satisfy: -3.2 < R11 / R12 < -2.

[0018] Further preferably, the object-side surface curvature radius R13 of the seventh lens and the image-side surface curvature radius R14 of the seventh lens satisfy: -0.8 < (R13+R14) / (R13-R14) < -0.2.

[0019] Further preferably, the focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: 1.1 < f1 / f8 < 2.2.

[0020] Further preferably, the back focal length BFL of the optical lens and the total track length TTL of the optical lens satisfy: 0.12 < BFL / TTL < 0.14.

[0021] Further preferably, the object-side half-hydraulic radius sag of the sixth lens SAG61, the image-side half-hydraulic radius sag of the sixth lens SAG62, and the central thickness CT6 of the sixth lens satisfy: 1.8 < (SAG62-SAG61) / CT6 < 5.

[0022] Further preferably, the Abbe number Vd3 of the third lens and the Abbe number Vd2 of the second lens satisfy: 14 < Vd3-Vd2 < 17.

[0023] Further preferably, the total track length TTL of the optical lens and the maximum diameter Dmax of all lenses in the optical lens satisfy: 4.2 < TTL / Dmax < 5.8.

[0024] Further preferably, the real image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half field angle of the optical lens satisfy: 0.98 < (IH / 2) / (f x θ) < 1.01.

[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, low distortion, 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 present application.

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

[0029] Figure 3 It is an F-Tan(Theta) distortion curve of the optical lens in the embodiment 1 of the present application.

[0030] Figure 4 It is an axial aberration curve of the optical lens in the embodiment 1 of the present application.

[0031] Figure 5 It is a sagittal color aberration curve of the optical lens in the embodiment 1 of the present application.

[0032] Figure 6 It is an MTF curve of the optical lens in the embodiment 1 of the present application.

[0033] Figure 7 It is a structure schematic diagram of the optical lens in the embodiment 2 of the present application.

[0034] Figure 8 It is a field curvature curve of the optical lens in the embodiment 2 of the present application.

[0035] Figure 9 It is an F-Tan(Theta) distortion curve of the optical lens in the embodiment 2 of the present application.

[0036] Figure 10 It is an axial aberration curve of the optical lens in the embodiment 2 of the present application.

[0037] Figure 11 It is a sagittal color aberration curve of the optical lens in the embodiment 2 of the present application.

[0038] Figure 12 It is an MTF curve of the optical lens in the embodiment 2 of the present application.

[0039] Figure 13 It is a structure schematic diagram of the optical lens in the embodiment 3 of the present application.

[0040] Figure 14 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0041] Figure 15 : This is the F-Tan (Theta) distortion curve of the optical lens in Example 3 of the present invention.

[0042] Figure 16 4 is an axial aberration curve diagram of the optical lens in Example 3 of the present invention.

[0043] Figure 17 Graph showing vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0044] Figure 18 This is the MTF curve of the optical lens in Example 3 of the present invention.

[0045] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0046] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of embodiments of the present application and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0047] It should be noted that in this specification, the terms "first," "second," "third," etc., are used solely to distinguish one feature from another and do not limit the features. Thus, the first lens discussed below could also be referred to as the second lens or the third lens without departing from the teachings of the present invention.

[0048] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0049] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, 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.

[0050] It should also be understood that the use of the terms "have", "has", "having", "include", "includes" or "including" when used in this specification, specifies the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. In addition, when referring to a list of items, the use of "at least one of" indicates that an item falling within any one or more of the listed items is contemplated. Furthermore, the use of "may" when describing embodiments of the present application indicates that one or more embodiments of the present application include the possibility of the use of such features. Also, the use of the term "example" is intended to mean an example or illustration rather than a preference or requirement.

[0051] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0052] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other if there is no conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0053] The optical lens of the embodiment of the present application comprises eight lenses, which are sequentially arranged along the optical axis from the object side to the imaging surface as follows: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

[0054] In some embodiments, the first lens can have a negative focal power, the object side surface of which is a concave surface, and the image side surface of which can be a concave surface or a convex surface. The second lens can have a positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface. The third lens can have a positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface. The fourth lens can have a negative focal power, the object side surface of which is a concave surface, and the image side surface of which can be a concave surface or a convex surface. The fifth lens can have a positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface. The sixth lens can have a negative focal power, the object side surface of which is a concave surface, and the image side surface of which is a concave surface. The seventh lens can have a positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface. The eighth lens can have a negative focal power, the object side surface of which is a concave surface, and the image side surface of which is a convex surface.

[0055] In some embodiments, the optical lens can further comprise a diaphragm, which can be located between the first lens and the second lens. It can be understood that the diaphragm is used to limit the amount of light to change the brightness of the imaging. When the diaphragm is located between the first lens and the second lens, it is convenient to correct the diaphragm aberration.

[0056] In some embodiments, the optical lens can further comprise a filter and a protective glass, which are arranged in sequence along the optical axis between the eighth lens and the imaging surface. The filter is used to filter out interference light, preventing the interference light from reaching the imaging surface of the optical lens and affecting normal imaging. The protective glass protects the optical lens, preventing the photosensitive chip from being damaged and affecting the imaging effect of the lens.

[0057] In some embodiments, the third lens and the fourth lens can be glued to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; 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.

[0058] In some embodiments, the fifth lens and the sixth lens can be glued to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; 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.

[0059] In some embodiments, the image side surface curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: 0.5 < R12 / f < 0.9. Satisfying the above range can make the sixth lens have a proper 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.

[0060] In some embodiments, the object side surface curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: -0.5 < R15 / f < -0.4; the image side surface curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: -4.8 < R16 / f < -3.2. Satisfying the above conditions, the eighth lens is a concave negative lens with a concave image side surface, which on the one hand increases the area of light entering the imaging surface, realizes large target surface imaging of the lens, and on the other hand suppresses the angle of the edge field of view incident on the imaging surface, improving the imaging quality.

[0061] In some embodiments, the object side surface curvature radius R11 of the sixth lens and the image side surface curvature radius R12 of the sixth lens satisfy: -3.2 < R11 / R12 < -2. The shape of the sixth lens is concave-concave, satisfying the above conditions, which makes the converging light of the large front end transition smoothly, helps to balance various aberrations, and reduces the sensitivity of the lens to a certain extent.

[0062] In some embodiments, the seventh lens has a radius of curvature R13 on the object side and a radius of curvature R14 on the image side, and the following relationship is established: -0.8 < (R13+R14) / (R13-R14) < -0.2. The above range is beneficial to increase the area of the light entering the imaging surface, achieve large target surface imaging of the lens, and improve the imaging quality of the optical lens.

[0063] In some embodiments, the first lens has a focal length f1 and the eighth lens has a focal length f8, and the following relationship is established: 1.1 < f1 / f8 < 2.2. By reasonably setting the focal length ratio of the first and last lenses, the lens can have a small head size while having a large imaging surface, and can better meet the balance of miniaturization and high pixels.

[0064] In some embodiments, the optical lens has a back focal length BFL and an optical total length TTL, and the following relationship is established: 0.12 < BFL / TTL < 0.14. The above range is beneficial to balance between obtaining good imaging quality and being easy to assemble, to ensure the imaging quality of the optical lens while avoiding interference between the lens and other elements, and to reduce the assembly process difficulty of the camera module.

[0065] In some embodiments, the sixth lens has a half-haugh radius sagittal height SAG61 on the object side, a half-haugh radius sagittal height SAG62 on the image side, and a central thickness CT6, and the following relationship is established: 1.8 < (SAG62-SAG61) / CT6 < 5. The above condition can control the surface shape of the object side of the sixth lens, which is beneficial to the manufacturing and shaping of the sixth lens and reduces the rejection rate. In addition, it can also avoid the surface shape being too curved and complex, so as to balance the field curvature.

[0066] In some embodiments, the third lens has an Abbe number Vd3 and the second lens has an Abbe number Vd2, and the following relationship is established: 14 < Vd3-Vd2 < 17. When the above relationship is satisfied, it is beneficial to select appropriate lens materials, thereby effectively correcting chromatic aberration, and further improving the imaging clarity of the optical system and the imaging quality of the optical system.

[0067] In some embodiments, the optical lens has an optical total length TTL and a maximum diameter Dmax of all lenses in the optical lens, and the following relationship is established: 4.2 < TTL / Dmax < 5.8. By controlling the ratio of the optical total length of the optical lens to the maximum diameter of all lenses to be small, the entire optical lens can be more compact, and miniaturization of the optical lens can be achieved.

[0068] In some embodiments, the real image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half field angle of the optical lens satisfy: 0.98 < (IH / 2) / (f x θ) < 1.01. Satisfying the above condition can better achieve small distortion and be more conducive to achieving high resolution.

[0069] In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 3.1 < TTL / IH < 3.7. Satisfying the above condition can better achieve miniaturization of the lens while ensuring that the lens has a larger image surface under the condition of the same total length, so that a larger size imaging chip can be matched to achieve high-definition imaging.

[0070] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2.1 < f1 / f < -1. Satisfying the above range can make a wide range of light enter the optical lens, obtain more picture information, and help control lens distortion and reduce field curvature to improve the geometric accuracy of the imaging surface.

[0071] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.9 < f2 / f < 1.4. Satisfying the above condition can control the light path, provide a more reasonable light incidence angle for subsequent lenses, and reduce astigmatism and field curvature.

[0072] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 0.8 < f3 / f < 1; and the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: -1.3 < f4 / f < -0.8. Satisfying the above conditions, the third lens and the fourth lens form a double cemented lens. The third lens and the fourth lens can have positive and negative opposite optical powers, so that various aberrations of the optical system are fully corrected, the resolution is improved, and the optical performance such as distortion is optimized under the premise of compact structure.

[0073] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.8 < f5 / f < 1.1; and the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -0.9 < f6 / f < -0.5. Satisfying the above conditions, the fifth lens and the sixth lens form a double cemented lens, and the fifth lens and the sixth lens can have positive and negative opposite optical powers, so that various aberrations of the optical lens are fully corrected, the resolution is improved, and high resolution is achieved. At the same time, the use of the cemented part is conducive to reducing the tolerance sensitivity of the lens to tilt / offset during assembly, improving the resolution stability, and further improving the system performance.

[0074] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 0.6 < f7 / f < 1.1. By satisfying the above condition, the seventh lens adopts positive refractive power, can further focus light, optimize imaging quality, and correct residual aberrations (such as distortion, chromatic aberration, etc.), thereby ensuring imaging clarity and color restoration.

[0075] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -1 < f8 / f < -0.8. By satisfying the above condition, the effective focal length of the eighth lens is small in value, and the light divergence effect is good, which can further increase the light quantity while ensuring high imaging quality.

[0076] In some embodiments, the combined focal length f34 of the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 2.5 < f34 / f < 7. By satisfying the above condition, the combined focal length of the third and fourth lenses is reasonably set, which is conducive to controlling the light path and can continue to gently converge the light emitted from the second lens, compress the height of the light on the image side of the fourth lens, and reduce the lens aperture, which is conducive to the miniaturization of the lens.

[0077] 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: -4 < f56 / f < 15. By satisfying the above condition, it is helpful for more light to enter the cemented lens smoothly and improve the illumination.

[0078] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 18° < FOV / Fno < 22°. By satisfying the above condition, it is conducive to improving the light quantity of the lens and realizing high-definition imaging.

[0079] In some embodiments, the object side curvature radius R3 of the second lens and the image side curvature radius R4 of the second lens satisfy: -1.1 < R3 / R4 < -0.6. By making the optical system satisfy the above relationship, the ratio of the object side curvature radius of the second lens and the image side curvature radius of the second lens is reasonably configured, the shape of the second lens is controlled, the spherical aberration, chromatic aberration and field curvature of the optical system are comprehensively balanced, the risk of ghosting is reduced, the resolving power of the optical system is improved, and the processing difficulty of the second lens is also reduced.

[0080] In some embodiments, the object side curvature radius R13 of the seventh lens and the image side curvature radius R14 of the seventh lens satisfy: -0.7 < R13 / R14 < -0.1. The shape of the seventh lens is double convex, and by satisfying the above condition, the light can be converged, the field curvature of the system can be balanced, and the image quality can be prevented from being degraded.

[0081] In some embodiments, the object-side surface curvature radius R15 of the eighth lens and the image-side surface curvature radius R16 of the eighth lens satisfy: 0.1 < R15 / R16 < 0.15. By satisfying the above condition, the incident light can be effectively diverged by reasonably setting the surface type of the eighth lens, the height of the light reaching the imaging surface is increased, and large target surface imaging of the lens is facilitated.

[0082] In some embodiments, the object-side surface curvature radius R3 of the second lens and the image-side surface curvature radius R4 of the second lens satisfy: -0.25 < (R3+R4) / (R3-R4) < 0.1; and the object-side surface curvature radius R5 of the third lens and the image-side surface curvature radius R6 of the third lens satisfy: -0.2 < (R5+R6) / (R5-R6) < 0.2. By satisfying the above conditions, the curvature radii of the object-side surface and the image-side surface of the second lens and the third lens are reasonably controlled, thereby facilitating the control of the shape of the second lens and the third lens, optimizing the aberration balance of the lens group, and improving the imaging quality.

[0083] In some embodiments, the object-side surface curvature radius R7 of the fourth lens and the image-side surface curvature radius R8 of the fourth lens satisfy: -1.3 < (R7+R8) / (R7-R8) < -0.5. By satisfying the above range, the light deflection angle can be reduced, the light trend is more stable, and the coma and field curvature can be corrected, thereby improving the flatness of imaging and the imaging quality of the optical lens.

[0084] In some embodiments, the object-side surface curvature radius R11 of the sixth lens and the image-side surface curvature radius R12 of the sixth lens satisfy: 0.35 < (R11+R12) / (R11-R12) < 0.55. By satisfying the above range, the shape of the object-side surface and the image-side surface of the sixth lens is reasonably controlled, the image height is increased, and high-definition imaging is achieved.

[0085] In some embodiments, the object-side surface curvature radius R15 of the eighth lens and the image-side surface curvature radius R16 of the eighth lens satisfy: -1.4 < (R15+R16) / (R15-R16) < -1.2. By satisfying the above range, the angle of the edge field incident on the imaging surface can be suppressed, more light beams can be effectively transmitted to the imaging surface, the field curvature and the spherical aberration of the optical lens can be balanced, and the imaging quality of the optical lens is improved.

[0086] In some embodiments, the image-side surface curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: -2.1 < R4 / f < -1.5. By satisfying the above condition, the image-side surface of the second lens is convex, the light is smoothly converged and transitioned, the light is not excessively emitted due to the light power of the first lens, and the difficulty of chromatic aberration correction of the optical lens is reduced.

[0087] In some embodiments, the image-side surface curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: -5.1 < R14 / f < -1.8. By setting the seventh lens to have a suitable surface shape within the above range, the light rays can be converged smoothly, the light rays can be smoothly transitioned to the rear, the height of the light rays incident to the rear can be reduced, the light energy loss caused by the excessively large angle between the main light ray and the chip in the edge field of view can be avoided, and the illumination of the edge field of view can be improved.

[0088] In some embodiments, the central thickness CT3 of the third lens and the central thickness CT4 of the fourth lens satisfy: 7.5 < CT3 / CT4 < 8.5. By matching the third lens and the fourth lens with each other within the above range, the on-axis chromatic aberration can be eliminated. In addition, the thicker third lens can block the edge stray light, and the overall rigidity of the lens group can be improved, which is suitable for high-vibration environments (such as vehicle-mounted lenses).

[0089] 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 < 9.8. By satisfying the above condition, the system performance sensitivity can be reduced, the lens processing and assembly stability can be ensured, and the assembly yield can be improved.

[0090] In some embodiments, the total length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis satisfy: 0.6 < ∑CT / TTL < 0.7. By satisfying the above condition, the total length of the optical lens can be effectively compressed, and the structure design and production process of the optical lens can be facilitated.

[0091] In some embodiments, the real image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 5 mm < IH / Fno < 6 mm. By satisfying the above condition, the optical lens can have a large image surface while ensuring that the optical lens has a large aperture, and the balance between the large image surface and the large aperture can be achieved.

[0092] In some embodiments, the edge thickness ET5 of the fifth lens and the central thickness CT5 of the fifth lens satisfy: 0.35 < ET5 / CT5 < 0.65, and the edge thickness ET6 of the sixth lens and the central thickness CT6 of the sixth lens satisfy: 2.3 < ET6 / CT6 < 6. By satisfying the above conditions of the fifth lens and the sixth lens, the field curvature can be reduced by using the curvature combination of the biconvex lens and the biconcave lens, and the center and the edge can be ensured to be clear at the same time.

[0093] In some embodiments, the image-side surface half-diameter sagittal height SAG42 of the fourth lens and the image-side surface half-diameter DM42 of the fourth lens satisfy: -0.1 < SAG42 / DM42 < 0.1. By satisfying the above condition, the central depression degree of the fourth lens can be limited, and the difficulty of aberration correction of the edge field of view can be reduced.

[0094] In some embodiments, the object-side half-aperture radius DM11 of the first lens and the image-side half-aperture radius DM82 of the eighth lens satisfy: 1.2 < DM11 / DM82 < 1.4. By reasonably setting the aperture ratio of the first and last lenses, the optical lens can have a smaller head size while having a larger imaging surface, which can better meet the balance of miniaturization and high pixels.

[0095] In some embodiments, the real image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 0.8 < IH / EPD < 1.2. Satisfying the above range makes the optical lens meet the large image surface while also meeting the sufficient image surface brightness of the edge field of view, preventing the occurrence of dark corner phenomenon, thereby improving the imaging quality.

[0096] In some embodiments, the optical lens satisfies the condition: 30mm < TTL < 34mm, 14mm < f < 17mm, 28° < FOV < 38°, 8mm < IH < 9mm, 1.5 < Fno < 1.8, 10° < CRA < 20°, wherein TTL represents the total optical length of the optical lens, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, IH represents the image height corresponding to the maximum field of view angle of the optical lens, Fno represents the aperture value of the optical lens, and CRA represents the chief ray angle of incidence at the maximum image height of the optical lens. Satisfying the above conditions indicates that the optical lens provided by the embodiments of the present application at least: has a telephoto characteristic, can guarantee the telephoto effect of the optical lens, so that the system has a large magnification and has good imaging quality for scenes in a long distance field of view; has a suitable field of view angle, which can clearly capture a target at a long distance; has a large image surface, which is suitable for a large target surface sensor and improves the imaging quality; has a large aperture, which further improves the light intake of the lens and can guarantee the clarity of the image in a weak light environment or at night; has a small CRA (not greater than 20°), which is conducive to improving the matching degree of the lens and the long-focus sensor (imaging chip) and improving the imaging clarity.

[0097] In some embodiments, the lens material in the optical lens provided by the present application 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 low dispersion characteristic of the glass can effectively correct the geometric chromatic aberration of the optical system. The optical lens provided by the present application can adopt a full-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0098] 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 a spherical lens or an aspherical lens. Compared with a spherical structure, an aspherical structure can effectively reduce aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving miniaturization of the lens. More specifically, the first lens and the second lens of the present application adopt a spherical lens or an aspherical lens; the seventh lens adopts an aspherical lens; the third lens, the fourth lens, the fifth lens, the sixth lens and the eighth lens adopt a spherical lens.

[0099] In various embodiments of the present application, when the lens adopts an aspherical lens, the shape of each aspherical surface of the optical lens satisfies the following equation:

[0100]

[0101] wherein z is the distance of the curved surface from the vertex of the curved surface in the direction of the optical axis, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the quadratic surface coefficient, and B, C, D, E and F are respectively the fourth-order, sixth-order, eighth-order, tenth-order and twelfth-order surface coefficients.

[0102] The present application is further described in the following embodiments. In various embodiments, the thickness, the radius of curvature and the material selection of each lens in the optical lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present application, but the embodiments of the present application are not limited to the following embodiments only, and any changes, substitutions, combinations or simplifications made without departing from the innovative points of the present application should be regarded as equivalent replacement modes, and are included in the protection scope of the present application.

[0103] Embodiment 1

[0104] Please refer to Figure 1 , which is a structural schematic diagram of the optical lens provided in the embodiment 1 of the present application. The optical lens comprises, along the optical axis from the object side to the imaging surface, a first lens L1, a diaphragm ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter G1 and a protective glass G2.

[0105] The first lens L1 has a negative focal power, the object side S1 is a concave surface, and the image side S2 is a convex surface.

[0106] The second lens L2 has a positive focal power, the object side S3 is a convex surface, and the image side S4 is a convex surface.

[0107] The third lens L3 has a positive focal power, the object side S5 is a convex surface, and the image side is a convex surface.

[0108] The fourth lens L4 has a negative focal power, the object side surface thereof is a concave surface, and the image side surface S7 is a convex surface;

[0109] The third lens L3 and the fourth lens L4 form a cemented lens group with a positive focal power, i.e., the cemented surface of the image side surface of the third lens L3 and the object side surface of the fourth lens L4 is S6;

[0110] The fifth lens L5 has a positive focal power, the object side surface S8 is a convex surface, and the image side surface thereof is a convex surface;

[0111] The sixth lens L6 has a negative focal power, the object side surface thereof is a concave surface, and the image side surface S10 is a concave surface;

[0112] The fifth lens L5 and the sixth lens L6 form a cemented lens group with a negative focal power, i.e., the cemented surface of the image side surface of the fifth lens L5 and the object side surface of the sixth lens L6 is S9;

[0113] The seventh lens L7 has a positive focal power, the object side surface S11 is a convex surface, and the image side surface S12 is a convex surface;

[0114] The eighth lens L8 has a negative focal power, the object side surface S13 is a concave surface, and the image side surface S14 is a convex surface;

[0115] The object side surface S15 and the image side surface S16 of the filter G1 are both flat surfaces;

[0116] The object side surface S17 and the image side surface S18 of the protective glass G2 are both flat surfaces;

[0117] The imaging surface S19 is a flat surface.

[0118] The second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the eighth lens are glass spherical lenses, and the first lens and the seventh lens are glass aspherical lenses.

[0119] The related parameters of the lenses in the optical lens in Embodiment 1 are shown in Table 1-1.

[0120] Table 1-1

[0121]

[0122]

[0123] The surface type parameters of the aspherical lenses of the optical lens in Embodiment 1 are shown in Table 1-2.

[0124] Table 1-2

[0125] Surface number K B C D E F S1 -3.5563E-01 2.3166E-05 2.4849E-07 -2.2421E-08 7.8092E-10 -1.0243E-11 S2 -4.6731E+01 2.0721E-05 2.8792E-07 -5.3045E-09 2.1425E-10 -3.4629E-12 S11 2.1409E+00 -3.0737E-04 -6.0478E-06 -2.4406E-07 1.1500E-08 -5.1818E-10 S12 -1.1683E+01 -2.1844E-04 -1.0759E-05 2.3129E-07 -1.9985E-08 2.4894E-10

[0126] In the present embodiment, the field curvature curve, the F-Tan(Theta) distortion curve, the axial aberration curve, the lateral chromatic aberration curve and the MTF curve of the optical lens are shown in FIGS. 1-5, respectively. Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6

[0127] Figure 2 The field curvature curve of Example 1 is shown, which represents the curvature of light rays of different wavelengths on the meridional image surface and the sagittal image surface, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.03mm, which indicates that the optical lens can well correct the field curvature.

[0128] Figure 3 The F-Tan(Theta) distortion curve of Example 1 is shown, which represents the distortion of light rays at different image heights on the imaging surface, the horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the distortion of the optical lens is controlled within -3%~0, which indicates that the optical lens can well correct the distortion.

[0129] Figure 4 The axial aberration curve of Example 1 is shown, which represents the axial aberration of each wavelength on the optical axis at the imaging surface, 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 offset of the axial aberration is controlled within ±0.02mm, which indicates that the optical lens can well correct the axial aberration.

[0130] Figure 5 The lateral chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.54μm) at different image heights on the imaging surface, the horizontal axis represents the lateral chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. As can be seen from the figure, the lateral chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1μm, which indicates that the optical lens can well correct the chromatic aberration.

[0131] Figure 6 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the present embodiment is above 0.5 within the full field of view, and in the range of 0-120lp / mm, the MTF curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in the case of low frequency and high frequency. ​

[0132] Example 2

[0133] See also Figure 7 , shown is a schematic structural diagram of an optical lens provided in Example 2 of the present invention. The optical lens of this embodiment is substantially the same as that of Example 1, with the main differences being that: the image-side surface S7 of the fourth lens element L4 is concave; the fifth lens element L5 and the sixth lens element L6 form a cemented lens group with positive power; the second lens element L2 is a glass aspheric lens; the protective glass G2 is not included; and the optical parameters such as the curvature radius, aspheric coefficient, and thickness of each lens surface are different.

[0134] The relevant parameters of each lens in the optical lens in Example 2 are shown in Table 2-1.

[0135] Table 2-1

[0136]

[0137]

[0138] The surface parameters of the aspheric lens of the optical lens in Example 2 are shown in Table 2-2.

[0139] Table 2-2

[0140] Surface number K B C D E F S1 -5.8022E-01 4.9130E-05 3.2508E-06 1.5966E-08 -1.7385E-09 2.0518E-11 S2 -1.3885E+01 5.5212E-05 3.5568E-06 1.9046E-08 -7.0465E-10 4.2185E-12 S3 -2.1066E+00 1.6741E-05 4.8913E-07 -2.6669E-09 -1.1560E-10 5.1286E-12 S4 4.8264E+00 -2.1094E-05 -4.0236E-07 8.9378E-09 2.8417E-12 4.9496E-13 S11 -7.7050E+00 -1.9833E-04 -6.0203E-06 2.8244E-07 -4.2257E-09 7.4001E-10 S12 1.0853E+01 -3.6288E-04 -4.2434E-06 5.8018E-08 9.5964E-09 4.7639E-10

[0141] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical chromatic aberration curve, and MTF curve of the optical lens are shown as follows: Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 、 Figure 12 shown.

[0142] from Figure 8 It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.03mmmm, indicating that the optical lens can correct the field curvature well.

[0143] from Figure 9 It can be seen that the distortion of the optical lens is controlled within -4% to 0, indicating that the optical lens can correct the distortion well.

[0144] from Figure 10 It can be seen that the offset of axial aberration is controlled within ±0.02mm, which shows that the optical lens can correct axial aberration well.

[0145] from Figure 11 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1μm, indicating that the optical lens can correct chromatic aberration well.

[0146] From Figure 12 it can be seen that the MTF value of the embodiment is above 0.5 in the full field of view, and in the range of 0-120 lp / mm, the MTF curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution in the case of low frequency and high frequency.

[0147] Embodiment 3

[0148] Please refer to Figure 13 , which is a structural schematic diagram of the optical lens provided in embodiment 3 of the application, and the optical lens of the embodiment is substantially the same as that of embodiment 1, and the main difference is that the image side S2 of the first lens L1 is a concave surface; the image side S7 of the fourth lens L4 is a concave surface; the first lens L1 is a glass spherical lens; the second lens L2 is a glass aspherical lens; the optical parameters such as the curvature radius, aspherical coefficient and thickness of each lens surface type are different.

[0149] The related parameters of each lens in the optical lens in embodiment 3 are shown in Table 3-1.

[0150] Table 3-1

[0151]

[0152]

[0153] The surface type parameters of the aspherical lens of the optical lens in embodiment 3 are shown in Table 3-2.

[0154] Table 3-2

[0155] Surface number K B C D E F S3 -4.9213E-01 -1.8497E-05 -2.8960E-08 2.2613E-08 -6.7683E-10 9.2329E-12 S4 -6.4691E+00 -7.3675E-06 -2.9031E-07 4.1560E-08 -1.1414E-09 1.3702E-11 S11 1.2559E+00 -1.9330E-04 -5.1720E-06 -9.9690E-09 -2.3904E-10 -1.0779E-10 S12 5.0000E+01 -1.0173E-04 -1.3110E-05 4.1455E-07 -2.3110E-08 3.5301E-10

[0156] In this embodiment, the field curvature curve, F-Tan(Theta) distortion curve, axial aberration curve, vertical axis chromatic aberration curve and MTF curve of the optical lens are shown in Figure 14 , Figure 15 , Figure 16 , Figure 17 , Figure 18 respectively.

[0157] From Figure 14 it can be seen that the field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.02mmmm, which indicates that the optical lens can well correct the field curvature.

[0158] From Figure 15 it can be seen that the distortion of the optical lens is controlled within-4%~0, which indicates that the optical lens can well correct the distortion.

[0159] FromFigure 16 It can be seen from the table 6 that the axial aberration offset is controlled within ±0.01 mm, which indicates that the optical lens can correct the axial aberration well.

[0160] From the table 6, it can be seen that the axial aberration offset is controlled within ±0.01 mm, which indicates that the optical lens can correct the axial aberration well. Figure 17

[0161] From the table 6, it can be seen that the axial aberration offset is controlled within ±0.01 mm, which indicates that the optical lens can correct the axial aberration well. Figure 18 From the table 6, it can be seen that the axial aberration offset is controlled within ±0.01 mm, which indicates that the optical lens can correct the axial aberration well.

[0162] Please refer to table 4, the optical characteristics corresponding to each of the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the real image height IH corresponding to the maximum field of view, the chief ray angle of incidence CRA at the maximum image height, the maximum field of view FOV, and the numerical value corresponding to each condition in each embodiment.

[0163] Table 4

[0164]

[0165]

[0166] In summary of the above embodiments, the optical lens provided by the present application adopts eight lenses with specific optical power, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved, so that the lens has one or more advantages of large aperture, long focal length, low distortion, high pixel, high imaging quality, etc.

[0167] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0168] ​The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An optical lens, comprising eight lenses, characterized in that: It successively includes from the object side to the imaging surface along the optical axis: A first lens with negative optical power, whose object side is concave; A second lens with positive optical power, whose object side is convex and whose image side is convex; A third lens with positive optical power, whose object side is convex and whose image side is convex; A fourth lens with negative optical power, whose object side is concave; A fifth lens with positive optical power, whose object side is convex and whose image side is convex; A sixth lens with negative optical power, whose object side is concave and whose image side is concave; A seventh lens with positive optical power, whose object side is convex and whose image side is convex; An eighth lens with negative optical power, whose object side is concave and whose image side is convex; Wherein, the radius of curvature R12 of the image side of the sixth lens and the effective focal length f of the optical lens satisfy: 0.5 < R12 / f < 0.

9.

2. The optical lens according to claim 1, wherein: The radius of curvature R15 of the object side of the eighth lens and the effective focal length f of the optical lens satisfy: -0.5 < R15 / f < -0.4; the radius of curvature R16 of the image side of the eighth lens and the effective focal length f of the optical lens satisfy: -4.8 < R16 / f < -3.

2.

3. The optical lens according to claim 1, wherein: The radius of curvature R11 of the object side of the sixth lens and the radius of curvature R12 of the image side of the sixth lens satisfy: -3.2 < R11 / R12 < -2.

4. The optical lens according to claim 1, wherein: The radius of curvature R13 of the object side of the seventh lens and the radius of curvature R14 of the image side of the seventh lens satisfy: -0.8 < (R13 + R14) / (R13 - R14) < -0.

2.

5. The optical lens according to claim 1, wherein: The focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: 1.1 < f1 / f8 < 2.

2.

6. The optical lens according to claim 1, wherein: The back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0.12 < BFL / TTL < 0.

14.

7. The optical lens according to claim 1, wherein: The sagittal height SAG61 of the object side clear aperture semi-diameter of the sixth lens, the sagittal height SAG62 of the image side clear aperture semi-diameter of the sixth lens and the central thickness CT6 of the sixth lens satisfy: 1.8 < (SAG62 - SAG61) / CT6 < 5.

8. The optical lens according to claim 1, wherein: The Abbe number Vd3 of the third lens and the Abbe number Vd2 of the second lens satisfy: 14 < Vd3 - Vd2 < 17.

9. The optical lens according to claim 1, wherein: The total optical length TTL of the optical lens and the maximum aperture Dmax of all the lenses in the optical lens satisfy: 4.2 < TTL / Dmax < 5.

8.

10. The optical lens according to claim 1, wherein: The true image height IH corresponding to the maximum field angle of view of the optical lens, the effective focal length f of the optical lens and the radian value θ of the maximum half field angle of view of the optical lens satisfy: 0.98 < (IH / 2) / (f×θ) < 1.01.

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