Optical lens

Abstract

The application provides an optical lens, which comprises eight lenses in sequence along an optical axis from an object side to an imaging surface, and the eight lenses comprise: a first lens with negative optical power, wherein the object side surface is a convex surface and the image side surface is a concave surface; a second lens with negative optical power, wherein the object side surface is a convex surface and the image side surface is a concave surface; a third lens with positive optical power, wherein the object side surface is a concave surface and the image side surface is a convex surface; a fourth lens with positive optical power, wherein the image side surface is a convex surface; a fifth lens with negative optical power, wherein the object side surface is a concave surface and the image side surface is a convex surface; a sixth lens with negative optical power, wherein the object side surface is a concave surface and the image side surface is a convex surface; a seventh lens with negative optical power, wherein the object side surface is a concave surface and the image side surface is a concave surface; and an eighth lens with positive optical power, wherein the object side surface is a convex surface and the image side surface is a convex surface. The optical lens provided by the application improves the imaging quality of the optical lens through reasonable configuration of the surface types of the lenses and reasonable matching of the optical powers.

Description

TECHNICAL FIELD

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

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

[0003] Advanced Driver Assistance System (ADAS) plays an important role in intelligent driving. It collects environmental information through various lenses combined with sensors to ensure the safety of drivers. The surround view lens is used to shoot the environment around the vehicle. The pictures captured by multiple cameras will be transmitted to the vehicle processor for real-time processing. The processor will correct, splice and fuse these pictures appropriately to generate a continuous, seamless and full-360-degree surround view image. The surround view lens generally uses a wide-angle lens, which has large distortion and poor imaging quality, making it difficult to meet user needs. Therefore, 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] The present application provides an optical lens, which has a total of eight lenses, and includes, along the optical axis from the object side to the imaging surface:

[0006] The first lens has negative focal power, the object side surface is convex, and the image side surface is concave;

[0007] The second lens has negative focal power, the object side surface is convex, and the image side surface is concave;

[0008] The third lens has positive focal power, the object side surface is concave, and the image side surface is convex;

[0009] The fourth lens has positive focal power, and the image side surface is convex;

[0010] The fifth lens has negative focal power, the object side surface is concave, and the image side surface is convex;

[0011] The sixth lens has negative focal power, the object side surface is concave, and the image side surface is convex;

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

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

[0014] An effective focal length f of the optical lens and a focal length f1 of the first lens satisfy: -6 < f1 / f < -4.

[0015] It is further preferred that an effective focal length f of the optical lens and a focal length f8 of the eighth lens satisfy: 1.7 < f8 / f < 2.1.

[0016] It is further preferred that a maximum field of view angle FOV of the optical lens and an aperture value Fno of the optical lens satisfy: 105° < FOV / Fno < 120°.

[0017] It is further preferred that a radius of curvature R13 of an object side surface of the seventh lens and an effective focal length f of the optical lens satisfy: -7 < R13 / f < -5.5.

[0018] It is further preferred that a focal length f1 of the first lens and a focal length f8 of the eighth lens satisfy: -3 < f1 / f8 < -2.2.

[0019] It is further preferred that a distance CT56 of the fifth lens and the sixth lens on the optical axis, a distance CT67 of the sixth lens and the seventh lens on the optical axis, a distance CT78 of the seventh lens and the eighth lens on the optical axis, and a central thickness CT6 of the sixth lens satisfy: 0.38 < (CT56 + CT67 + C78) / CT6 < 0.5.

[0020] It is further preferred that a half diameter of light passing DM11 of an object side surface of the first lens and a half diameter of light passing DM82 of an image side surface of the eighth lens satisfy: 2.8 < DM11 / DM82 < 3.6.

[0021] It is further preferred that a real image height IH corresponding to a maximum field of view angle of the optical lens, an effective focal length f of the optical lens, and an arc value θ of a maximum half field of view angle of the optical lens satisfy: 0.99 < (IH / 2) / (f x θ) < 1.01.

[0022] It is further preferred that a real image height IH corresponding to a maximum field of view angle of the optical lens and an entrance pupil diameter EPD of the optical lens satisfy: 5.5 < IH / EPD < 7.2.

[0023] It is further preferred that a half diameter of light passing sagittal height SAG81 of an object side surface of the eighth lens, a half diameter of light passing sagittal height SAG82 of an image side surface of the eighth lens, and a central thickness CT8 of the eighth lens satisfy: -0.7 < (SAG82 - SAG81) / CT8 < -0.6.

[0024] 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, short focus, super large field of view, small distortion, high imaging quality and the like. BRIEF DESCRIPTION OF DRAWINGS

[0025] 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:

[0026] Figure 1 It is a structure schematic diagram of the optical lens in the embodiment 1 of the application.

[0027] Figure 2 It is a field curvature curve of the optical lens in the embodiment 1 of the application.

[0028] Figure 3 It is an F-Theta distortion curve of the optical lens in the embodiment 1 of the application.

[0029] Figure 4 It is an axial aberration curve of the optical lens in the embodiment 1 of the application.

[0030] Figure 5 It is a lateral chromatic aberration curve of the optical lens in the embodiment 1 of the application.

[0031] Figure 6 It is a structure schematic diagram of the optical lens in the embodiment 2 of the application.

[0032] Figure 7 It is a field curvature curve of the optical lens in the embodiment 2 of the application.

[0033] Figure 8 It is an F-Theta distortion curve of the optical lens in the embodiment 2 of the application.

[0034] Figure 9 It is an axial aberration curve of the optical lens in the embodiment 2 of the application.

[0035] Figure 10 It is a lateral chromatic aberration curve of the optical lens in the embodiment 2 of the application.

[0036] Figure 11 It is a structure schematic diagram of the optical lens in the embodiment 3 of the application.

[0037] Figure 12 It is a field curvature curve of the optical lens in the embodiment 3 of the application.

[0038] Figure 13 It is an F-Theta distortion curve of the optical lens in the embodiment 3 of the application.

[0039] Figure 14 Axial aberration curve of the optical lens in Embodiment 3 of the present application.

[0040] Figure 15 Axial aberration curve of the optical lens in Embodiment 3 of the present application.

[0041] The following detailed description will further describe the present application with reference to the above-mentioned drawings. DETAILED DESCRIPTION

[0042] For a better understanding of the present application, various aspects of the present application will be described in more detail below with reference to the accompanying drawings. It is to be noted that these detailed descriptions are only descriptions of embodiments of the present application and are not intended in any way to limit the scope of the present application. Throughout the specification, like reference numerals refer to like elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0043] It should be noted that the expressions first, second, third and the like in this specification are used only to distinguish one feature from another feature, and do not indicate any limitation on the features. Thus, the first lens discussed below can also be referred to as a second lens or a third lens without departing from the teachings of the present application.

[0044] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for the sake of explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0045] In this specification, the paraxial region refers to a region near the optical axis. If a 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 a 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 image plane is referred to as the image side surface of the lens.

[0046] It should also be understood that the use of the terms "including", "including having", "having", "containing", and / or "containing having" when used in this specification intends that existence of stated features, elements and / or components but does not exclude the presence or addition of one or more other features, elements, components, and / or groups thereof. In addition, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the term "exemplary" is intended to mean an example or an illustration.

[0047] 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.

[0048] 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 accompanying drawings and in combination with the embodiments.

[0049] The optical lens provided by the embodiments of the present application comprises eight lenses, which are sequentially arranged along the optical axis from the object side to the imaging surface and include 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.

[0050] In some embodiments, the first lens can have a negative focal power, the object side surface of which is convex, and the image side surface of which is concave. The second lens can have a negative focal power, the object side surface of which is convex, and the image side surface of which is concave. The third lens can have a positive focal power, the object side surface of which is concave, and the image side surface of which is convex. The fourth lens can have a positive focal power, the object side surface of which can be concave or convex, and the image side surface of which is convex. The fifth lens can have a negative focal power, the object side surface of which is concave, and the image side surface of which is convex. The sixth lens can have a negative focal power, the object side surface of which is concave, and the image side surface of which is convex. The seventh lens can have a negative focal power, the object side surface of which is concave, and the image side surface of which is concave. The eighth lens can have a positive focal power, the object side surface of which is convex, and the image side surface of which is convex.

[0051] In some embodiments, the optical lens can further comprise a diaphragm, which can be located between the third lens and the fourth 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 third lens and the fourth lens, the correction of the diaphragm aberration is facilitated.

[0052] In some embodiments, the optical lens can further include a filter disposed between the eighth lens and the imaging surface. The filter is configured to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0053] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -6 < f1 / f < -4. With the above condition satisfied, the first lens has an appropriate negative focal length, which is conducive to expanding the field of view of the optical lens.

[0054] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 1.7 < f8 / f < 2.1. With the above condition satisfied, the eighth lens helps to reasonably collect light, ensure the amount of light, and improve the relative luminance, so that the brightness of the optical lens at the image surface is improved.

[0055] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 105° < FOV / Fno < 120°. With the above condition satisfied, the light amount of the lens is improved, and the lens can also achieve high-definition imaging in a dark environment.

[0056] In some embodiments, the object side surface radius of curvature R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -7 < R13 / f < -5.5. With the above range satisfied, the seventh lens has an appropriate surface shape, which is conducive to balancing the astigmatism and field curvature of the optical lens and improving the imaging quality of the optical lens.

[0057] In some embodiments, the focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: -3 < f1 / f8 < -2.2. With the above condition satisfied, by reasonably setting the focal length relationship of the first and last lenses in the lens, the area of light entering the imaging surface is increased while ensuring as much light as possible to enter the system, which is conducive to realizing large image surface imaging of the lens while increasing the light amount and improving the relative luminance of the system.

[0058] In some embodiments, the distance CT56 between the fifth lens and the sixth lens on the optical axis, the distance CT67 between the sixth lens and the seventh lens on the optical axis, the distance CT78 between the seventh lens and the eighth lens on the optical axis, and the center thickness CT6 of the sixth lens satisfy: 0.38 < (CT56 + CT67 + C78) / CT6 < 0.5. With the above condition satisfied, the gap between the fifth lens, the sixth lens, the seventh lens, and the eighth lens and the size of the center thickness of the sixth lens are reasonably arranged, which is conducive to realizing the miniaturization feature of the system.

[0059] 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: 2.8 < DM11 / DM82 < 3.6. By satisfying the above condition, by reasonably setting the ratio of the apertures of the first and last lenses, the lens can have a smaller head size while having a larger imaging surface, which can better meet the balance of miniaturization and high pixels.

[0060] 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: 0.99 < (IH / 2) / (f x θ) < 1.01. By satisfying the above condition, small distortion can be better achieved, and high resolution can be more favorably achieved.

[0061] In some embodiments, the real image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 5.5 < IH / EPD < 7.2. By satisfying the above range, the optical lens can satisfy sufficient image plane brightness in the edge field while satisfying a large image plane, preventing dark corner phenomenon, thereby improving imaging quality.

[0062] In some embodiments, the object-side half-aperture sag height SAG81 of the eighth lens, the image-side half-aperture sag height SAG82 of the eighth lens, and the central thickness CT8 of the eighth lens satisfy: -0.7 < (SAG82-SAG81) / CT8 < -0.6. By satisfying the above condition, by controlling the relationship between the sag height height difference of the image side and the object side of the eighth lens and the central thickness of the eighth lens, it is beneficial to correct the coma of the off-axis field, and it is beneficial to improve the imaging quality of the optical lens off-axis field.

[0063] In some embodiments, the back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0.16 < BFL / TTL < 0.18. By satisfying the above condition, by reasonably configuring the ratio of the back focal length of the optical lens to the total optical length of the optical lens, it is beneficial to realize the short back focal length of the optical lens, and in the case of ensuring sufficient space for optical element installation and focusing, it is beneficial to realize the miniaturization of the optical lens.

[0064] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 10 < TTL / f < 11.5. By satisfying the above condition, the length of the lens can be effectively limited, which is beneficial to realize the miniaturization of the optical lens.

[0065] 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: 57°<(f*FOV) / IH<58°. By reasonably limiting the relationship among the focal length, the field of view, and the image height of the optical lens, the above condition formula is satisfied, which is conducive to achieving a balance between a large field of view and a large target surface imaging of the optical lens, and better meeting the use requirements of the vehicle-mounted surround-view camera.

[0066] In some embodiments, the real image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 3.2<IH / f<3.8. By satisfying the above condition, an ultra-large field of view and imaging range can be achieved, which can ensure the depth of field of the optical lens while realizing a large image surface characteristic, thereby improving the imaging quality of the optical system.

[0067] 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 of the optical lens satisfy: 3<TTL / IH<3.3. By satisfying the above condition, the miniaturization of the lens can be better realized, while ensuring that the lens has a large image surface under the condition of the same total length, which can match a large-size imaging chip to realize high-definition imaging.

[0068] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -4<f2 / f<-3. By satisfying the above condition, the second lens also adopts a negative lens, which can further diverge light rays and improve the field of view of the imaging system.

[0069] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 3.2<f3 / f<5, and the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 2.4<f4 / f<3. By satisfying the above conditions, the third and fourth lenses converge the incident light rays at the front end, which is conducive to correcting the aberration and edge field distortion caused by the front lens group, so that the lens has smaller distortion and can provide high-definition imaging effect.

[0070] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.8<f7 / f<-1.6. By satisfying the above condition, the seventh lens has an appropriate negative focal length, which is conducive to further increasing the imaging area of the optical lens while balancing various aberrations generated by the front lens group, thereby improving the imaging quality of the optical lens.

[0071] In some embodiments, 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: 32° / mm<FOV / IH<40° / mm. Satisfying the above condition, the optical lens has a large field of view characteristic under the premise of meeting the image height requirement, so that the optical lens has good optical performance and well captures the details of the object.

[0072] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.7<BFL / f<1.9. Satisfying the above range, a balance between good imaging quality and easy assembly of the optical back focal length is achieved, which ensures the imaging quality of the optical lens while avoiding interference between the lens and other elements and reducing the assembly process difficulty of the camera module.

[0073] 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: 2.6<R1 / R2<3.5. Satisfying the above condition, the surface shape of the first lens can be reasonably set to enhance the light collecting ability of the first lens, thereby realizing an ultra-large field of view.

[0074] 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: 2.6<R5 / R6<3.5. Satisfying the above condition, the third lens can balance the system field curvature to avoid edge image quality degradation.

[0075] In some embodiments, the object side surface curvature radius R9 of the fifth lens and the image side surface curvature radius R10 of the fifth lens satisfy: 0.88<R9 / R10<0.96; and the object side surface curvature radius R11 of the sixth lens and the image side surface curvature radius R12 of the sixth lens satisfy: 0.9<R11 / R12<0.96. Satisfying the above conditions, by reasonably setting the surface shape of the fifth lens and the sixth lens, the light smoothly transitions, which is conducive to the correction of astigmatism and field curvature, improves the imaging quality of the optical lens, and ensures the stability of the optical system.

[0076] In some embodiments, the object side surface curvature radius R13 of the seventh lens and the image side surface curvature radius R14 of the seventh lens satisfy: -5.5<R13 / R14<-4. Satisfying the above range, the seventh lens is a double-concave lens, and the curvature radius of the seventh lens is reasonably set to correct the aberration of the optical lens and reduce the tolerance sensitivity of the optical lens.

[0077] 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: -0.8 < R15 / R16 < -0.6. Satisfying the above range, the surface shape of the eighth lens is reasonably limited, which helps the light rays to be accurately focused on the imaging plane, and improves the definition and uniformity of brightness of the imaging.

[0078] 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: 2 < (R5+R6) / (R5-R6) < 2.8. Satisfying the above range, the light rays can be more stable, and the coma and field curvature can be corrected, thereby improving the flatness of the imaging and the imaging quality of the optical lens.

[0079] In some embodiments, the object-side surface curvature radius R13 of the seventh lens and the image-side surface curvature radius R14 of the seventh lens satisfy: 0.6 < (R13+R14) / (R13-R14) < 0.7. Satisfying the above range, the object-side surface curvature radius and the image-side surface curvature radius of the seventh lens are reasonably controlled, thereby being conducive to controlling the shape of the seventh lens, correcting the aberration generated by itself, and improving the imaging quality.

[0080] 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: -0.3 < (R15+R16) / (R15-R16) < -0.1. Satisfying the above range, the shape of the object-side surface and the image-side surface of the eighth lens is reasonably limited, which can control the eighth lens to have a proper surface shape, help to control the light ray trend of the edge field of view, and improve the imaging quality of the edge field of view.

[0081] In some embodiments, the central thickness CT3 of the third lens and the central thickness CT4 of the fourth lens satisfy: 2.5 < CT3 / CT4 < 3.3. Satisfying the above condition, the ratio of the thickness of the third lens on the optical axis and the thickness of the fourth lens on the optical axis is reasonably configured, and the third lens and the fourth lens can be adjusted to each other, thereby maintaining the miniaturization feature of the optical system.

[0082] 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: 0.5 < ∑CT / TTL < 0.6. Satisfying the above condition, the total length of the optical lens can be effectively compressed, and meanwhile, the structure design and the production process of the optical lens are facilitated.

[0083] 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: 2.7 mm < IH / Fno < 3.5 mm. Satisfying the above condition, the optical lens has 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 is achieved.

[0084] In some embodiments, the seventh lens satisfies the following condition: 1.5 < (SAG72-SAG71) / CT7 < 1.7, where SAG71 is the sagittal height of the half entrance pupil of the object side surface of the seventh lens, SAG72 is the sagittal height of the half entrance pupil of the image side surface of the seventh lens, and CT7 is the central thickness of the seventh lens. The above condition can control the surface shape of the object side surface of the seventh lens, which is conducive to the manufacture and shaping of the seventh lens and reduces the rejection rate. In addition, the surface shape is not too complex, and the system field curvature tends to be balanced.

[0085] In some embodiments, the optical lens satisfies the following conditions: 16mm < TTL < 18mm, 1.4mm < f < 1.7mm, 195° < FOV < 210°, 5.3mm < IH < 5.8mm, 1.6 < Fno < 2, where 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, and Fno represents the aperture value of the optical lens. The above conditions indicate that the optical lens provided by the embodiments of the present application at least has the following advantages: a small total optical length; a short focal length and a wide angle, so that the depth of field of the short focal length lens is deep, and the subject in front and behind can remain relatively clear; a super large field of view angle, which provides a wider shooting field of view for the vehicle-mounted surround view lens and other application scenarios, and captures more image information; a large imaging surface, which can match a large size chip to realize high-definition imaging; and a large aperture, which can realize high-definition imaging even in a complex light environment.

[0086] 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 first lens and the fourth lens in the optical lens provided by the present application can be made of glass, and the second lens, the third lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens can be made of plastic. The use of the glass-plastic hybrid structure can effectively reduce the cost, correct the aberration, reduce the size, improve the thermal stability and provide a higher cost-effective optical lens product.

[0087] 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 be a spherical lens or an aspherical lens. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses and better realizing the miniaturization of the lens. More specifically, the first lens and the fourth lens of the present application are spherical lenses, and the second lens, the third lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are aspherical lenses.

[0088] 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:

[0089] ;

[0090] 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 the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients, respectively.

[0091] 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 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 regarded as equivalent replacement methods, and are included in the protection scope of the present application.

[0092] Embodiment 1

[0093] Please refer to Figure 1 , which is a structural schematic diagram of the optical lens 100 provided in the embodiment 1 of the present application. The optical lens sequentially includes a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1 along the optical axis from the object side to the imaging surface.

[0094] The first lens L1 has a negative focal power, the object side surface S1 thereof is a convex surface, and the image side surface S2 thereof is a concave surface;

[0095] The second lens L2 has a negative focal power, the object side surface S3 thereof is a convex surface, and the image side surface S4 thereof is a concave surface;

[0096] The third lens L3 has a positive focal power, the object side surface S5 thereof is a concave surface, and the image side surface S6 thereof is a convex surface;

[0097] The fourth lens L4 has a positive focal power, the object side surface S7 thereof is a convex surface, and the image side surface S8 thereof is a convex surface;

[0098] The fifth lens L5 has a negative focal power, the object side surface S9 thereof is a concave surface, and the image side surface S10 thereof is a convex surface;

[0099] The sixth lens L6 has a negative focal power, the object side surface S11 thereof is a concave surface, and the image side surface S12 thereof is a convex surface;

[0100] The seventh lens L7 has negative focal power, the object side surface S13 is a concave surface, and the image side surface S14 is a concave surface;

[0101] The eighth lens L8 has positive focal power, the object side surface S15 is a convex surface, and the image side surface S16 is a convex surface;

[0102] The object side surface S17 and the image side surface S18 of the filter G1 are both planar surfaces;

[0103] The imaging surface S19 is a planar surface.

[0104] The first lens L1 and the fourth lens L4 are glass spherical lenses, and the second lens L2, the third lens L3, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are plastic aspherical lenses.

[0105] The related parameters of the lenses in the optical lens in Embodiment 1 are shown in Table 1-1.

[0106] Table 1-1

[0107]

[0108] The surface type parameters of the aspherical lenses of the optical lens in Embodiment 1 are shown in Table 1-2.

[0109] Table 1-2

[0110]

[0111] In this embodiment, the field curvature curve, the F-Theta distortion curve, the axial aberration curve, and the transverse aberration curve of the optical lens are shown in FIGS. Figure 2 、 Figure 3 、 Figure 4 、 Figure 5

[0112] Figure 2 The field curvature curve of Embodiment 1 is shown, which represents the curvature of light rays 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 -0.05 mm~0.1 mm, which shows that the optical lens can well correct the field curvature.

[0113] Figure 3 The F-Theta distortion curve of Embodiment 1 is shown, which represents the F-Theta distortion of light rays at different image heights on the imaging surface, the horizontal axis represents the F-Theta distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within -1.2%~3%, which shows that the optical lens can well correct the distortion.​

[0114] Figure 4 The axial aberration curve of the optical lens of Example 1 is shown in the figure, which represents the aberration of the optical axis at the imaging surface at each wavelength, 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 shift of the axial aberration is controlled within -0.01mm~0.02mm, which shows that the optical lens can correct the axial aberration well.

[0115] Figure 5 The axial aberration curve of the optical lens of Example 1 is shown in the figure, which represents the aberration of the optical axis at the imaging surface at each wavelength, 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 shift of the axial aberration is controlled within -0.01mm~0.02mm, which shows that the optical lens can correct the axial aberration well.

[0116] Example 2

[0117] Please refer to Figure 6 , which is a structural schematic diagram of the optical lens 200 provided in Example 2 of the present application. Compared with Example 1, the difference between the two embodiments lies in that the optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.

[0118] The related parameters of each lens in the optical lens in Example 2 are shown in Table 2-1.

[0119] Table 2-1

[0120]

[0121] The surface type parameters of the aspherical lens of the optical lens in Example 2 are shown in Table 2-2.

[0122] Table 2-2

[0123]

[0124] In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve and axial aberration curve of the optical lens are shown in Figure 7 , Figure 8 , Figure 9 , Figure 10 .

[0125] Figure 7The field curvature curve of the embodiment 2 is shown, which represents the bending degree of light rays 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-0.05mm~0.05mm, which shows that the optical lens can correct the field curvature well.

[0126] Figure 8 The F-Theta distortion curve of the embodiment 2 is shown, which represents the F-Theta distortion of light rays at different image heights on the imaging surface, the horizontal axis represents the F-Theta distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the F-Theta distortion of the optical lens is controlled within-1.2%~3%, which shows that the optical lens can correct the distortion well.

[0127] Figure 9 The axial aberration curve of the embodiment 2 is shown, which represents the 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-0.01mm~0.02mm, which shows that the optical lens can correct the axial aberration well.

[0128] Figure 10 The axial aberration curve of the embodiment 2 is shown, which represents the 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-0.01mm~0.02mm, which shows that the optical lens can correct the axial aberration well.

[0129] Embodiment 3

[0130] Please refer to Figure 11 , which is a structural schematic diagram of the optical lens 300 provided in the embodiment 3 of the present application. Compared with the embodiment 1, the difference lies in that the object side S7 of the fourth lens L4 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0131] The related parameters of each lens in the optical lens in the embodiment 3 are shown in Table 3-1.

[0132] Table 3-1

[0133]

[0134] The surface type parameters of the aspheric lens of the optical lens in the embodiment 3 are shown in Table 3-2.

[0135] Table 3-2

[0136]

[0137] In the present embodiment, the field curvature curve, the F-Theta distortion curve, the axial aberration curve and the transverse chromatic aberration curve of the optical lens are shown in FIGS. 1-4, respectively. Figure 12 、 Figure 13 、 Figure 14 、 Figure 15

[0138] Figure 12 The field curvature curve of Example 3 is shown, which represents the curvature of light rays on the sagittal image surface and the tangential 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 sagittal image surface and the tangential image surface is controlled within -0.15mm~0.05mm, which shows that the optical lens can well correct the field curvature.

[0139] Figure 13 The F-Theta distortion curve of Example 3 is shown, which represents the F-Theta distortion of light rays at different image heights on the imaging surface, the horizontal axis represents the F-Theta distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within 0~3%, which shows that the optical lens can well correct the distortion.

[0140] Figure 14 The axial aberration curve of Example 3 is shown, which represents the 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 -0.01mm~0.02mm, which shows that the optical lens can well correct the axial aberration.

[0141] Figure 15 The transverse chromatic aberration curve of Example 3 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.555μm) at different image heights on the imaging surface, the horizontal axis represents the transverse 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 transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -4μm~6μm, which shows that the optical lens can well correct the chromatic aberration.

[0142] Referring to Table 4, the optical properties corresponding to each of the above embodiments are shown, 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 angle, the chief ray angle CRA at the maximum image height, the maximum field of view angle FOV of the optical lens, and the numerical values corresponding to each conditional expression in each embodiment.

[0143] Table 4​

[0144]

[0145] In summary of the above embodiments, the optical lens provided by the present 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 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, short focal length, super large field of view, small distortion, high imaging quality, etc.

[0146] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like 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.

[0147] The above-described embodiments only express several implementation manners of the present application, and the description is relatively 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 those skilled in the art, without departing from the concept of the present application, a number of 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, eight pieces of lenses in total, characterized in that, In order from the object side to the imaging surface along the optical axis, the optical lens comprises in sequence: a first lens with negative refractive power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; a second lens with negative refractive power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; a third lens with positive refractive power, the object side surface of which is a concave surface, and the image side surface of which is a convex surface; a fourth lens with positive refractive power, the image side surface of which is a convex surface; a fifth lens with negative refractive power, the object side surface of which is a concave surface, and the image side surface of which is a convex surface; a sixth lens with negative refractive power, the object side surface of which is a concave surface, and the image side surface of which is a convex surface; a seventh lens with negative refractive power, the object side surface of which is a concave surface, and the image side surface of which is a concave surface; an eighth lens with positive refractive power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; an eighth lens with positive refractive power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -6 < f1 / f < -4.

2. The optical lens of claim 1, wherein, The object side surface half entrance pupil diameter DM11 of the first lens and the image side surface half entrance pupil diameter DM82 of the eighth lens satisfy: 2.8 < DM11 / DM82 < 3.

6.

3. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 1.7 < f8 / f < 2.

1.

4. The optical lens of claim 1, wherein, The maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 105° < FOV / Fno < 120°.

5. The optical lens of claim 1, wherein, The object side surface curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -7 < R13 / f < -5.

5.

6. The optical lens of claim 1, wherein, The focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: -3 < f1 / f8 < -2.

2.

7. The optical lens of claim 1, wherein, The distance CT56 between the fifth lens and the sixth lens on the optical axis, the distance CT67 between the sixth lens and the seventh lens on the optical axis, the distance CT78 between the seventh lens and the eighth lens on the optical axis, and the central thickness CT6 of the sixth lens satisfy: 0.38 < (CT56+CT67+C78) / CT6 < 0.

5.

8. The optical lens of claim 1, wherein, The object side surface half entrance pupil diameter sag height SAG71 of the seventh lens, the image side surface half entrance pupil diameter sag height SAG72 of the seventh lens, and the central thickness CT7 of the seventh lens satisfy: 1.5 < (SAG72-SAG71) / CT7 < 1.

7.

9. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field 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 of view of the optical lens satisfy: 0.99 < (IH / 2) / (f x θ) < 1.

01.

10. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 5.5 < IH / EPD < 7.

2. The object side surface half entrance pupil diameter sag height SAG81 of the eighth lens, the image side surface half entrance pupil diameter sag height SAG82 of the eighth lens, and the central thickness CT8 of the eighth lens satisfy: -0.7 < (SAG82-SAG81) / CT8 < -0.6.

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