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 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. According to the optical lens provided by the invention, the imaging quality of the optical lens can be improved, the aberration is reduced, and the imaging quality of the optical lens is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of imaging lenses, and particularly to an optical lens. BACKGROUND

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

[0003] Advanced Driver Assistance System (ADAS) plays an important role in intelligent driving, which collects environmental information through various lenses combined with sensors to ensure the safety of drivers. In addition to the requirements of optical lenses for the existing ADAS system, such as light and thin shape, high pixel, high resolution and other characteristics, 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 convex, and the image 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;

[0015] The object side surface curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: 2.1 < R1 / f < 6.8; the image side surface curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: 0.6 < R2 / f < 1.2.

[0016] Further preferably, the combined focal length f34 of the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 2.3 < f34 / f < 3.6.

[0017] Further preferably, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.7 < f5 / f < 0.9; the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -0.8 < f6 / f < -0.5.

[0018] Further preferably, the total track length TTL of the optical lens and the maximum aperture Dmax in all lenses in the optical lens satisfy: 4.7 < TTL / Dmax < 5.

[0019] Further preferably, the object side surface curvature radius R1 of the first lens and the image side surface curvature radius R2 of the first lens satisfy: 3 < R1 / R2 < 5.8.

[0020] 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) < -0.5.

[0021] Further preferably, the image side surface curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: 0.4 < R12 / f < 0.9.

[0022] Further preferably, the focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: 1.7 < f1 / f8 < 2.9.

[0023] Further preferably, the object side surface half-aperture sagittal height SAG11 of the first lens and the object side surface half-aperture DM11 of the first lens satisfy: -0.1 < SAG11 / DM11 < 0.1; the image side surface half-aperture sagittal height SAG12 of the first lens and the image side surface half-aperture DM12 of the first lens satisfy: 0.14 < SAG12 / DM12 < 0.26.

[0024] Further preferably, the object side surface half-aperture DM11 of the first lens and the image side surface half-aperture DM82 of the eighth lens satisfy: 1.1 < DM11 / DM82 < 1.4.

[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] Figure 19 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

[0046] Figure 20 4 is a field curvature curve diagram of the optical lens in Example 4 of the present invention.

[0047] Figure 21 : This is the F-Tan (Theta) distortion curve of the optical lens in Example 4 of the present invention.

[0048] Figure 22 4 is an axial aberration curve diagram of the optical lens in Example 4 of the present invention.

[0049] Figure 23 Graph showing vertical axis chromatic aberration of the optical lens in Example 4 of the present invention.

[0050] Figure 24 This is the MTF curve of the optical lens in Example 4 of the present invention.

[0051] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0052] 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.

[0053] It should be noted that the terms first, second, third, etc. in the present specification are only used to distinguish one feature from another, and do not represent any limitation on the features. Therefore, the first lens discussed below can also be referred to as the second lens or the third lens without departing from the teachings of the present application.

[0054] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shape of the spherical surface or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical surface or aspherical surface is not limited to the shape of the spherical surface or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn strictly to scale.

[0055] In this context, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the imaging surface is referred to as the image side surface of the lens.

[0056] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, specify 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 expressions such as "at least one of" appear after a list of one or more items, the phrase "at least one of" modifies the entire list of items and does not modify the list of items individually. Furthermore, when describing embodiments of the present application, the use of "may" indicates that "one or more embodiments of the present application". Also, the word "exemplary" is intended to mean an example or an illustration.

[0057] 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 should also be understood that the terms 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.

[0058] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0059] The optical lens of the embodiment of the present application has a total of eight lenses, which are, in order along the optical axis from the object side to the imaging surface: 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.

[0060] In some embodiments, the first lens can have a negative focal power, a convex object side surface, and a concave image side surface. The second lens can have a positive focal power, a convex object side surface, and a convex image side surface. The third lens can have a positive focal power, a convex object side surface, and a convex image side surface. The fourth lens can have a negative focal power, a concave object side surface, and a concave or convex image side surface. The fifth lens can have a positive focal power, a convex object side surface, and a convex image side surface. The sixth lens can have a negative focal power, a concave object side surface, and a concave image side surface. The seventh lens can have a positive focal power, a convex object side surface, and a convex image side surface. The eighth lens can have a negative focal power, a concave object side surface, and a concave or convex image side surface.

[0061] In some embodiments, the optical lens can further include 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, the correction of the diaphragm aberration is facilitated.

[0062] In some embodiments, the optical lens can further include a filter and a protective glass, which can be sequentially arranged along the optical axis between the eighth lens and the imaging surface. The filter is used to filter out the interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting the normal imaging. The protective glass plays a role in protecting the optical lens to prevent the light-sensitive chip from being damaged and affecting the imaging effect of the lens.

[0063] 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.

[0064] 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.

[0065] In some embodiments, the first lens satisfies: 2.1 < R1 / f < 6.8, where R1 is the curvature radius of the object side surface of the first lens, and f is the effective focal length of the optical lens; and the first lens satisfies: 0.6 < R2 / f < 1.2, where R2 is the curvature radius of the image side surface of the first lens, and f is the effective focal length of the optical lens. When the above ranges are satisfied, the first lens is a meniscus negative lens, and the reasonable configuration of the ratio of the curvature radius of the object side surface and the image side surface of the first lens to the effective focal length of the optical lens can make the first lens collect as many light rays as possible in a large field of view and smoothly enter the rear system, increase the light flux of the optical lens, and effectively expand the field of view of the optical lens.

[0066] In some embodiments, the third lens and the fourth lens satisfy: 2.3 < f34 / f < 3.6, where f34 is the combined focal length of the third lens and the fourth lens, and f is the effective focal length of the optical lens. When the above range is satisfied, the reasonable configuration of the combined focal length of the third lens and the fourth lens is beneficial to control the light path and can continue to gently converge the light rays emitted by the second lens, compress the height of the light rays emitted from the image side surface of the fourth lens, and reduce the lens aperture, which is beneficial to the miniaturization of the lens.

[0067] In some embodiments, the fifth lens satisfies: 0.7 < f5 / f < 0.9, where f5 is the focal length of the fifth lens, and f is the effective focal length of the optical lens; and the sixth lens satisfies: -0.8 < f6 / f < -0.5, where f6 is the focal length of the sixth lens, and f is the effective focal length of the optical lens. When the above ranges are satisfied, the fifth lens and the sixth lens form a double cemented lens, and the fifth lens and the sixth lens can have opposite positive and negative refractive 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 cemented lens is beneficial to reduce the tolerance sensitivity of the lens to tilt and eccentricity in the assembly process, improve the resolution stability, and further improve the system performance.

[0068] In some embodiments, the optical total length TTL of the optical lens and the maximum aperture Dmax of all lenses in the optical lens satisfy: 4.7 < TTL / Dmax < 5. When the ratio of the optical total length of the optical lens to the maximum aperture of all lenses is small, the entire optical lens can be more compact, and the miniaturization of the optical lens can be achieved.

[0069] In some embodiments, the first lens satisfies: 3 < R1 / R2 < 5.8, where R1 is the curvature radius of the object side surface of the first lens, and R2 is the curvature radius of the image side surface of the first lens. When the above condition is satisfied, the first lens is a double-concave lens, which can pre-compensate the field curvature introduced by the positive lens group, make the image plane more flat, and improve the image resolution.

[0070] 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 condition is met: -0.8 < (R13+R14) / (R13-R14) < -0.5. Meeting the above range can 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.

[0071] In some embodiments, the sixth lens has a radius of curvature R12 on the image side and the effective focal length f of the optical lens, and the following condition is met: 0.4 < R12 / f < 0.9. Meeting the above range can make the sixth lens have an appropriate surface shape, balance the astigmatism and field curvature of the optical lens, and improve the imaging quality of the optical lens.

[0072] In some embodiments, the first lens has a focal length f1 and the eighth lens has a focal length f8, and the following condition is met: 1.7 < f1 / f8 < 2.9. Meeting the above range can make the lens have a smaller head size while having a larger imaging surface, and better balance miniaturization and high pixels.

[0073] In some embodiments, the first lens has a sagittal height SAG11 of a half diameter of the light passing through the object side and a half diameter DM11 of the light passing through the object side, and the following condition is met: -0.1 < SAG11 / DM11 < 0.1; the first lens has a sagittal height SAG12 of a half diameter of the light passing through the image side and a half diameter DM12 of the light passing through the image side, and the following condition is met: 0.14 < SAG12 / DM12 < 0.26. Meeting the above conditions can limit the central concave degree of the object side and the image side of the first lens, and reduce the aberration correction difficulty of the edge field of view.

[0074] In some embodiments, the first lens has a half diameter DM11 of the light passing through the object side and the eighth lens has a half diameter DM82 of the light passing through the image side, and the following condition is met: 1.1 < DM11 / DM82 < 1.4. Meeting the above range can make the lens have a smaller head size while having a larger imaging surface, and better balance miniaturization and high pixels.

[0075] In some embodiments, the optical lens has a back focal length BFL and an optical total length TTL, and the following condition is met: 0.09 < BFL / TTL < 0.13. Meeting the above range can balance good imaging quality and easy assembly, ensure the imaging quality of the optical lens, avoid interference between the lens and other elements, and reduce the assembly process difficulty of the camera module.

[0076] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the real image height IH corresponding to the maximum field of view FOV of the optical lens satisfy: 56°<(f*FOV) / IH<59°. Satisfying the above condition, a larger field of view and imaging range can be achieved, the large image surface characteristics can be realized while ensuring the depth of field of the optical lens, and thus the imaging quality of the optical system is improved.

[0077] In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view FOV of the optical lens satisfy: 3.4<TTL / IH<3.8. Satisfying the above condition, the miniaturization of the lens can be better realized, and meanwhile, the lens has a larger image surface under the condition of the same total length, which can match a larger imaging chip to realize high-definition imaging.

[0078] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2<f1 / f<-1.3. Satisfying the above range, a large range of light can enter the optical lens, more picture information can be obtained, and the lens distortion and field curvature can be controlled, and the geometric precision of the imaging surface is improved.

[0079] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 1.5<f2 / f<1.8. Satisfying the above condition, the light path can be controlled, and a more reasonable light incidence angle is provided for the subsequent lens, and the astigmatism and field curvature are reduced.

[0080] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 0.9<f3 / f<1.8, and the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: -3.2<f4 / f<-1.3. Satisfying the above conditions, the third lens and the fourth lens are glued to form a double-glued 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.

[0081] 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. Satisfying the above condition, the seventh lens adopts positive optical power, which can further focus light, optimize imaging quality, and correct residual aberrations (such as distortion, chromatic aberration, etc.), so as to ensure the imaging clarity and color restoration.

[0082] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -0.9<f8 / f<-0.6. Satisfying the above condition, the effective focal length of the eighth lens is small, and the light divergence effect is good, which can further increase the light flux while ensuring high imaging quality.

[0083] 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: -80 < f56 / f < 15. Satisfying the above condition helps more light rays to enter the cemented lens smoothly and helps to improve the illumination.

[0084] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 21° < FOV / Fno < 28°. Satisfying the above condition is conducive to improving the light intake of the lens and realizing high-definition imaging.

[0085] 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: -1.8 < R3 / R4 < -0.5. By making the optical system satisfy the above relationship, the ratio of the object side surface curvature radius of the second lens and the image side surface 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.

[0086] In some embodiments, the object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: -1.4 < R5 / R6 < -0.8. Satisfying the above condition, the third lens can balance the system field curvature and avoid edge image quality degradation.

[0087] 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: -1.7 < R11 / R12 < -1.2. The shape of the sixth lens is concave-concave, satisfying the above condition makes the converging light rays of the large aperture at the front end transition smoothly, helps to balance various aberrations, and to some extent reduces the lens sensitivity.

[0088] In some embodiments, the object side surface curvature radius R1 of the first lens and the image side surface curvature radius R2 of the first lens satisfy: 1.4 < (R1+R2) / (R1-R2) < 2. The surface shape of the first lens satisfying the above condition is conducive to the divergence of light rays, obtaining a larger picture, which can effectively eliminate aberration and improve the resolving power of the optical lens.

[0089] 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: -0.3 < (R3+R4) / (R3-R4) < 0.3; the object-side surface curvature radius R5 of the third lens and the image-side surface curvature radius R6 of the third lens satisfy: -0.1 < (R5+R6) / (R5-R6) < 0.2. By satisfying the above conditions, 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.

[0090] 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: -1.9 < (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.

[0091] 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: 0.1 < (R11+R12) / (R11-R12) < 0.3. 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.

[0092] 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: -1.2 < (R15+R16) / (R15-R16) < 0.1. By satisfying the above range, the angle of the edge field incident on the imaging surface is suppressed, more light beams are effectively transmitted to the imaging surface, the field curvature and the spherical aberration of the optical lens are balanced, and the imaging quality of the optical lens is improved.

[0093] In some embodiments, the center thickness CT3 of the third lens and the center thickness CT4 of the fourth lens satisfy: 2.5 < CT3 / CT4 < 10. By satisfying the above relationship, the two lenses match each other, which helps to eliminate the on-axis chromatic aberration. In addition, the thicker third lens can block the edge stray light, and also improve the overall rigidity of the lens group, which is suitable for high-vibration environments (such as vehicle-mounted lenses).

[0094] In some embodiments, the center thickness CT5 of the fifth lens and the center thickness CT6 of the sixth lens satisfy: 3.5 < CT5 / CT6 < 12. By satisfying the above conditions, the system performance sensitivity can be reduced, while ensuring the lens processing and assembly stability, and improving the assembly yield.

[0095] In some embodiments, the total track length TTL of the optical lens and the sum of the central thicknesses of the first lens to the eighth lens along the optical axis respectively ∑CT satisfy: 0.6 < ∑CT / TTL < 0.8. Satisfying the above condition can effectively compress the total length of the optical lens, while being conducive to the structural design and production process of the optical lens.

[0096] In some embodiments, the real image height IH corresponding to the maximum field of view angle of the optical lens and the aperture value Fno of the optical lens satisfy: 5.5mm < IH / Fno < 6.5mm. Satisfying the above condition can maintain a large image surface of the optical lens while ensuring a large aperture of the optical lens, achieving a balance between a large image surface and a large aperture.

[0097] In some embodiments, the edge thickness ET5 of the fifth lens and the central thickness CT5 of the fifth lens satisfy: 0.2 < ET5 / CT5 < 0.5; the edge thickness ET6 of the sixth lens and the central thickness CT6 of the sixth lens satisfy: 2.6 < ET6 / CT6 < 7. The fifth lens and the sixth lens satisfying the above condition can reduce the field curvature by using the curvature combination of the biconvex and biconcave lenses, and ensure that the center and the edge are clear at the same time.

[0098] In some embodiments, the half-surface sagittal height SAG61 of the object side of the sixth lens, the half-surface sagittal height SAG62 of the image side of the sixth lens, and the central thickness CT6 of the sixth lens satisfy: 1.7 < (SAG62-SAG61) / CT6 < 6. Satisfying the above condition can control the surface shape of the object side of the sixth lens, which is conducive to the manufacturing and forming 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 system field curvature.

[0099] 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: 0.9 < IH / EPD < 1.1. Satisfying the above range can make the optical lens satisfy a large image surface while also satisfying that the edge field of view has sufficient image surface brightness to prevent dark corner phenomenon, thereby improving the imaging quality.

[0100] In some embodiments, the Abbe number Vd3 of the third lens and the Abbe number Vd2 of the second lens satisfy: 0.15 < (Vd3-Vd2) / Vd2 < 0.33. When the above relationship is satisfied, it is conducive to selecting appropriate lens materials, so that the chromatic aberration can be effectively corrected, thereby improving the imaging clarity of the optical system and the imaging quality of the optical system.

[0101] 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: 0.97 < (IH / 2) / (f x θ) < 1.03. Satisfying the above condition can better achieve small distortion and be more conducive to achieving high resolution.

[0102] In some embodiments, the optical lens satisfies the condition: 30mm < TTL < 36mm, 13mm < f < 16mm, 34° < FOV < 42°, 9mm < IH < 9.5mm, 1.4 < Fno ≤ 1.6, 17° < CRA < 23°, 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 angle of the optical lens, IH represents the image height corresponding to the maximum field 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 condition 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, and makes the system have a large magnification, has a good imaging quality for scenes in a relatively far field of view; has a suitable field angle, can clearly capture a target at a distance; has a large image surface, is suitable for a large target surface sensor, and improves the imaging quality; has a large aperture, further improves the light intake of the lens, and can guarantee the clarity of an image in a weak light environment or at night; has a small CRA (not greater than 23°), and a small CRA is conducive to improving the matching degree of the lens and a long-focus sensor (imaging chip) and improving the imaging clarity.

[0103] 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 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 application can adopt a full-glass lens structure, can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0104] 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 the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving lens miniaturization. More specifically, the first lens, the second lens, and the seventh lens of the present application adopt an aspherical lens, and the third lens, the fourth lens, the fifth lens, the sixth lens, and the eighth lens adopt a spherical lens.

[0105] In various embodiments of the present application, when the lens adopts an aspheric lens, the shape of each aspheric surface of the optical lens satisfies the following equation:

[0106]

[0107] 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, F, G, and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients, respectively.

[0108] 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 found in the parameter table of each embodiment. The following embodiments are merely 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 considered as equivalent replacement methods and are included in the protection scope of the present application.

[0109] Embodiment 1

[0110] Please refer to Figure 1 , which is a structural schematic diagram of the optical lens provided in Embodiment 1 of the present application. The optical lens includes, in order from the object side to the imaging surface along the optical axis, a first lens L1, a stop 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, and a filter G1.

[0111] The first lens L1 has a negative focal power, the object side S1 is a convex surface, and the image side S2 is a concave surface.

[0112] 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.

[0113] 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.

[0114] The fourth lens L4 has a negative focal power, the object side is a concave surface, and the image side S7 is a convex surface.

[0115] The third lens L3 and the fourth lens L4 form a cemented lens group with a positive focal power, that is, the cemented surface of the image side of the third lens L3 and the object side of the fourth lens L4 is S6.

[0116] The fifth lens L5 has a positive focal power, the object side S8 is a convex surface, and the image side is a convex surface.

[0117] The sixth lens L6 has negative refractive power, the object side surface thereof is a concave surface, and the image side surface S10 thereof is a concave surface;

[0118] The fifth lens L5 and the sixth lens L6 constitute a cemented lens group with negative refractive 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;

[0119] The seventh lens L7 has positive refractive power, the object side surface S11 thereof is a convex surface, and the image side surface S12 thereof is a convex surface;

[0120] The eighth lens L8 has negative refractive power, the object side surface S13 thereof is a concave surface, and the image side surface S14 thereof is a concave surface;

[0121] The object side surface S15 and the image side surface S16 of the filter G1 are both flat surfaces;

[0122] The imaging surface S17 is a flat surface.

[0123] The third lens, the fourth lens, the fifth lens, the sixth lens and the eighth lens are glass spherical lenses, and the first lens, the second lens and the seventh lens are glass aspherical lenses.

[0124] The related parameters of the lenses in the optical lens in Embodiment 1 are shown in Table 1-1.

[0125] Table 1-1

[0126]

[0127]

[0128] The surface type parameters of the aspherical lenses of the optical lens in Embodiment 1 are shown in Table 1-2.

[0129] Table 1-2

[0130]

[0131] In this embodiment, the field curvature curve, the F-Tan(Theta) distortion curve, the axial aberration curve, the transverse chromatic aberration curve and the MTF curve of the optical lens are shown in Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 respectively.

[0132] Figure 2The field curvature curve of the embodiment 1 is shown, which represents the bending degree 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: °). It can be seen from the figure that the field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.06mm, which shows that the optical lens can correct the field curvature well.

[0133] Figure 3 The F-Tan (Theta) distortion curve of the embodiment 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: °). It can be seen from the figure that the distortion of the optical lens is controlled within -3%~0, which shows that the optical lens can correct the distortion well.

[0134] Figure 4 The axial aberration curve of the embodiment 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. It can be seen from the figure that the offset of the axial aberration is controlled within ±0.02mm, which shows that the optical lens can correct the axial aberration well.

[0135] Figure 5 The sagittal chromatic aberration curve of the embodiment 1 is shown, which represents the chromatic aberration of each wavelength at different image heights on the imaging surface relative to the central wavelength (0.54μm), the horizontal axis represents the sagittal chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the sagittal chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±3μm, which shows that the optical lens can correct the chromatic aberration well.

[0136] Figure 6 The MTF (Modulation Transfer Function) curve of the embodiment 1 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF value of the embodiment is above 0.45 in 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, which has good imaging quality and good detail resolution ability in the case of low frequency and high frequency.

[0137] Embodiment 2

[0138] Please refer to Figure 7 , which is a structural schematic diagram of the optical lens provided in the embodiment 2 of the present application, and the optical lens of the embodiment is substantially the same as that of the embodiment 1, and the main difference is that the image side S14 of the eighth lens L8 is a convex surface; the optical parameters such as the curvature radius, the aspheric coefficient and the thickness of each lens surface are different.

[0139] The related parameters of each lens in the optical lens in Embodiment 2 are shown in Table 2-1.

[0140] Table 2-1

[0141]

[0142]

[0143] The surface shape parameters of the aspherical lens of the optical lens in Embodiment 2 are shown in Table 2-2.

[0144] Table 2-2

[0145]

[0146] In this embodiment, the field curvature curve, F-Tan(Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve and MTF curve of the optical lens are shown in Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 、 Figure 12 respectively.

[0147] It can be seen from Figure 8 that the field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.02mmmm, which shows that the optical lens can well correct the field curvature.

[0148] It can be seen from Figure 9 that the distortion of the optical lens is controlled within -2%~0, which shows that the optical lens can well correct the distortion.

[0149] It can be seen from Figure 10 that the shift of the axial aberration is controlled within ±0.01mm, which shows that the optical lens can well correct the axial aberration.

[0150] It can be seen from Figure 11 that the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2μm, which shows that the optical lens can well correct the chromatic aberration.

[0151] It can be seen from Figure 12 that the MTF value of this embodiment is above 0.6 in the full field of view, and in the range of 0~120lp / mm, the MTF curve is uniformly and smoothly decreased 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.

[0152] Embodiment 3

[0153] Please refer to Figure 13, shown is a schematic structural diagram of the optical lens provided in Example 3 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 fifth lens L5 and the sixth lens L6 form a cemented lens group with positive power; and the optical parameters such as the curvature radius, aspheric coefficient, and thickness of each lens surface are different.

[0154] The relevant parameters of each lens in the optical lens in Example 3 are shown in Table 3-1.

[0155] Table 3-1

[0156]

[0157] The surface parameters of the aspheric lens of the optical lens in Example 3 are shown in Table 3-2.

[0158] Table 3-2

[0159]

[0160] 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 14 、 Figure 15 、 Figure 16 、 Figure 17 、 Figure 18 shown.

[0161] from Figure 14 It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.02mmmm, indicating that the optical lens can correct the field curvature well.

[0162] from Figure 15 It can be seen that the distortion of the optical lens is controlled within -3% to 0, which shows that the optical lens can correct the distortion well.

[0163] from Figure 16 It can be seen that the offset of axial aberration is controlled within ±0.01mm, which shows that the optical lens can correct axial aberration well.

[0164] from Figure 17 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2μm, indicating that the optical lens can correct chromatic aberration well.

[0165] from Figure 18 As can be seen, the MTF value of this embodiment is above 0.45 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies.

[0166] Embodiment 4

[0167] Referring to Figure 19 , a structural schematic diagram of an optical lens provided in Embodiment 4 of the present application is shown, the optical lens of the present embodiment is substantially the same as that of Embodiment 1, the difference mainly lies in that the fifth lens L5 and the sixth lens L6 constitute a cemented lens group with positive focal power; the image side surface S7 of the fourth lens L4 is a concave surface; the optical parameters such as the curvature radius, asphericity coefficient and thickness of each lens surface are different.

[0168] The related parameters of each lens in the optical lens in Embodiment 4 are shown in Table 4-1.

[0169] Table 4-1

[0170]

[0171]

[0172] The surface profile parameters of the aspheric lens of the optical lens in Embodiment 4 are shown in Table 4-2.

[0173] Table 4-2

[0174]

[0175] In the present embodiment, the field curvature curve, F-Tan(Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve and MTF curve of the optical lens are shown in Figure 20 , Figure 21 , Figure 22 , Figure 23 , Figure 24 respectively.

[0176] It can be seen from Figure 20 that the field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.03mmmm, which indicates that the optical lens can well correct the field curvature.

[0177] It can be seen from Figure 21 that the distortion of the optical lens is controlled within -2%~0, which indicates that the optical lens can well correct the distortion.

[0178] It can be seen from Figure 22 that the shift of the axial aberration is controlled within ±0.05mm, which indicates that the optical lens can well correct the axial aberration.

[0179] It can be seen from Figure 23 that the transverse 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.

[0180] From Figure 24 It can be seen from the above that the MTF value of the embodiment is above 0.48 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.

[0181] Please refer to Table 5 for the optical properties corresponding to each of the above embodiments, including the effective focal length f, 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 conditional expression in each embodiment.

[0182] Table 5

[0183]

[0184]

[0185] 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.

[0186] 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 conjunction 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.

[0187] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as limiting the scope of the patent of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection 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 sequentially includes, from the object side to the imaging surface along the optical axis: A first lens with negative optical power, whose object side is convex and whose image side is concave; A second lens with 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; Wherein, the radius of curvature R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: 2.1 < R1 / f < 6.8; the radius of curvature R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: 0.6 < R2 / f < 1.

2.

2. The optical lens according to claim 1, wherein: The combined focal length f34 of the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 2.3 < f34 / f < 3.

6.

3. The optical lens according to claim 1, wherein: The focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.7 < f5 / f < 0.9; the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -0.8 < f6 / f < -0.

5.

4. The optical lens according to claim 1, wherein: The overall optical length TTL of the optical lens and the maximum aperture Dmax of all the lenses in the optical lens satisfy: 4.7 < TTL / Dmax < 5.

5. The optical lens according to claim 1, wherein: The radius of curvature R1 of the object side of the first lens and the radius of curvature R2 of the image side of the first lens satisfy: 3 < R1 / R2 < 5.

8.

6. 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.

5.

7. The optical lens according to claim 1, 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: 0.4 < R12 / f < 0.

9.

8. 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: 1.7 < f1 / f8 < 2.

9.

9. The optical lens according to claim 1, wherein: The sagittal height SAG11 of the semi-aperture of the object side of the first lens and the semi-aperture DM11 of the object side of the first lens satisfy: -0.1 < SAG11 / DM11 < 0.1; the sagittal height SAG12 of the semi-aperture of the image side of the first lens and the semi-aperture DM12 of the image side of the first lens satisfy: 0.14 < SAG12 / DM12 < 0.

26.

10. The optical lens according to claim 1, wherein: The semi-aperture DM11 of the object side of the first lens and the semi-aperture DM82 of the image side of the eighth lens satisfy: 1.1 < DM11 / DM82 < 1.4.

Images