Optical lens

Abstract

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

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, and in particular to an optical lens. Background Art

[0002] As people's requirements for driving experience continue to increase, automotive optical lenses are increasingly used in intelligent driving, and the status of automotive optical lenses in the automotive-related industries continues to improve.

[0003] Advanced Driver Assistance Systems (ADAS) play a crucial role in intelligent driving. They use a variety of lenses and sensors to collect environmental information to ensure driver safety. Surround-view cameras capture the vehicle's surroundings. Images captured by multiple cameras are ultimately transmitted to an onboard processor for real-time processing. The processor then performs appropriate corrections, stitching, and fusion to produce a continuous, seamless, and comprehensive 360-degree surround view image. Surround-view cameras typically use wide-angle lenses, which suffer from significant distortion and poor image quality, making them difficult to meet user needs. Therefore, it is necessary to develop an optical lens with excellent imaging performance. Summary of the Invention

[0004] In view of the above problems, an object of the present invention is to provide an optical lens having the advantage of excellent imaging quality.

[0005] The present invention provides an optical lens, comprising eight lenses, which include the following lenses in order from the object side to the imaging surface along the optical axis: a first lens having negative optical power, wherein the object-side surface is convex and the image-side surface is concave; a second lens having negative optical power, the object-side surface of which is convex and the image-side surface of which is concave; a third lens element having positive optical power, whose object-side surface is concave and whose image-side surface is convex; a fourth lens element having positive refractive power and a convex image-side surface; a fifth lens element having negative optical power, whose object-side surface is concave and whose image-side surface is convex; a sixth lens element having negative optical power, whose object-side surface is concave and whose image-side surface is convex; a seventh lens element having negative optical power, whose object-side surface and image-side surface are concave; an eighth lens element having positive refractive power, whose object-side surface is convex and whose image-side surface is convex; The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: <f1 / f<-4。

[0006] Further preferably, 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。

[0007] Further preferably, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens meet the following requirements: 105° <FOV / Fno<120°。

[0008] Further preferably, the object side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: <R13 / f<-5.5。

[0009] Further preferably, the focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: <f1 / f8<-2.2。

[0010] Further preferably, the distance CT56 on the optical axis between the fifth lens and the sixth lens, the distance CT67 on the optical axis between the sixth lens and the seventh lens, the distance CT78 on the optical axis between the seventh lens and the eighth lens, and the center thickness CT6 of the sixth lens satisfy the following relationship: 0.38<(CT56+CT67+CT78) / CT6<0.5.

[0011] Further preferably, the object-side light semi-aperture DM11 of the first lens and the image-side light semi-aperture DM82 of the eighth lens satisfy the following relationship: 2.8 <DM11 / DM82<3.6。

[0012] Further preferably, the real image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens and the arc value θ of the maximum half field angle of the optical lens satisfy: 0.99<(IH / 2) / (f×θ)<1.01.

[0013] Further preferably, the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 5.5 <IH / EPD<7.2。

[0014] Further preferably, the object-side clear light half-aperture sag height SAG81 of the eighth lens, the image-side clear light half-aperture sag height SAG82 of the eighth lens, and the center thickness CT8 of the eighth lens satisfy: -0.7<(SAG82-SAG81) / CT8<-0.6.

[0015] The optical lens provided by the present invention uses eight lenses with specific optical powers. Through the combination of specific surface shapes and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, so that the lens has one or more advantages such as large aperture, short focus, ultra-large field of view, small distortion, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which: Figure 1 Schematic diagram of the structure of the optical lens in Example 1 of the present invention.

[0017] Figure 2 Graph showing the field curvature of the optical lens in Example 1 of the present invention.

[0018] Figure 3 : is the F-Theta distortion curve of the optical lens in Example 1 of the present invention.

[0019] Figure 4 1 is an axial aberration curve diagram of the optical lens in Example 1 of the present invention.

[0020] Figure 5 Graph showing the vertical axis chromatic aberration of the optical lens in Example 1 of the present invention.

[0021] Figure 6 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0022] Figure 7 Graph showing the field curvature of the optical lens in Example 2 of the present invention.

[0023] Figure 8 : is the F-Theta distortion curve of the optical lens in Example 2 of the present invention.

[0024] Figure 9 2 is an axial aberration curve diagram of the optical lens in Example 2 of the present invention.

[0025] Figure 10 Graph showing vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0026] Figure 11 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0027] Figure 12 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0028] Figure 13 : This is the F-Theta distortion curve of the optical lens in Example 3 of the present invention.

[0029] Figure 14 4 is an axial aberration curve diagram of the optical lens in Example 3 of the present invention.

[0030] Figure 15 Graph showing vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0031] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0032] 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.

[0033] It should be noted that in this specification, the terms "first," "second," "third," etc., are used solely to distinguish one feature from another and do not limit the features. Thus, the first lens discussed below could also be referred to as the second lens or the third lens without departing from the teachings of the present invention.

[0034] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0035] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0036] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application." And, the term "exemplary" is intended to refer to an example or illustration.

[0037] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in a commonly used dictionary) shall be interpreted as having a meaning 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.

[0038] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments may be combined with each other. The following will detail this application by referring to the drawings and in combination with the embodiments.

[0039] The optical lens provided by the embodiment of the present invention has a total of eight lenses, which sequentially 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 along the optical axis from the object side to the imaging surface.

[0040] In some embodiments, the first lens may have a negative optical power, with its object side being convex and its image side being concave. The second lens may have a negative optical power, with its object side being convex and its image side being concave. The third lens may have a positive optical power, with its object side being concave and its image side being convex. The fourth lens may have a positive optical power, with its object side being concave or convex and its image side being convex. The fifth lens may have a negative optical power, with its object side being concave and its image side being convex. The sixth lens may have a negative optical power, with its object side being concave and its image side being convex. The seventh lens may have a negative optical power, with its object side being concave and its image side being concave. The eighth lens may have a positive optical power, with its object side being convex and its image side being convex.

[0041] In some embodiments, the optical lens may further include an aperture stop, and the aperture stop may be located between the third lens and the fourth lens. It can be understood that the aperture stop is used to limit the amount of incident light to change the brightness of the image. When the aperture stop is located between the third lens and the fourth lens, it is convenient for correcting the aperture aberration.

[0042] In some embodiments, the optical lens may further include a filter, and the filter is disposed between the eighth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0043] 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. Meeting the above conditions, the first lens has an appropriate negative focal length, which is beneficial to expanding the field angle of the optical lens.

[0044] 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. The eighth lens satisfying the above conditions helps to reasonably collect light, ensure the light passing amount, improve the relative illumination, and enhance the brightness at the image plane of the optical lens.

[0045] 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°. Satisfying the above conditions is beneficial to increasing the light incident amount of the lens, enabling the lens to achieve high-definition imaging even in a dim environment.

[0046] In some embodiments, the radius of curvature R13 of the object side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -7 < R13 / f < -5.5. Satisfying the above range can endow the seventh lens with an appropriate surface shape, which is beneficial to balancing the astigmatism and field curvature of the optical lens and improving the imaging quality of the optical lens.

[0047] 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. Satisfying the above conditions, by reasonably setting the focal length relationship between the first and last lenses in the lens, while ensuring that as much light as possible enters the system, the area of light entering the imaging plane is increased, which is beneficial to achieving large image plane imaging of the lens, while increasing the light incident amount and improving the relative illumination of the system.

[0048] 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 central thickness CT6 of the sixth lens satisfy: 0.38 < (CT56 + CT67 + C78) / CT6 < 0.5. Satisfying the above conditions, reasonably arranging the gap between the fifth lens, the sixth lens, the seventh lens and the eighth lens and the size of the central thickness of the sixth lens is beneficial to realizing the miniaturization characteristics of the system.

[0049] In some embodiments, the clear aperture radius DM11 of the object side surface of the first lens and the clear aperture radius DM82 of the image side surface of the eighth lens satisfy: 2.8 < DM11 / DM82 < 3.6. Satisfying the above conditions, 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 plane, and can better meet the balance of miniaturization and high pixel.

[0050] In some embodiments, the true 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×θ) < 1.01. Satisfying the above conditions can better achieve small distortion and is more beneficial to achieving high resolution.

[0051] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 5.5 < IH / EPD < 7.2. Meeting the above range enables the optical lens to satisfy a large image plane while also ensuring sufficient image plane brightness in the edge field of view, preventing vignetting, and thus improving the imaging quality.

[0052] In some embodiments, the object-side clear aperture sag SAG81 of the eighth lens, the image-side clear aperture sag SAG82 of the eighth lens, and the central thickness CT8 of the eighth lens satisfy: -0.7 < (SAG82 - SAG81) / CT8 < -0.6. Meeting the above conditions, by controlling the relationship between the sag height difference between the image side and the object side of the eighth lens and the central thickness of the eighth lens, it is beneficial to correct the coma of the off-axis field of view and improve the imaging quality of the off-axis field of view of the optical lens.

[0053] 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. Meeting the above conditions, reasonably configuring the ratio of the back focal length of the optical lens to the total optical length of the optical lens is beneficial to achieving a short back focal length of the optical lens, and is beneficial to miniaturizing the optical lens while ensuring sufficient space for the installation and focusing of optical elements.

[0054] 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. Meeting the above conditions can effectively limit the length of the lens and is beneficial to miniaturizing the optical lens.

[0055] In some embodiments, the effective focal length f of the optical lens, the maximum field angle FOV of the optical lens, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 57° < (f × FOV) / IH < 58°. Meeting the above conditional formula, by reasonably restricting the relationship between the focal length, field angle, and image height of the optical lens, it is beneficial to achieve the balance of large field angle and large target surface imaging of the optical lens, and better meet the usage requirements of vehicle-mounted surround-view cameras.

[0056] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 3.2 < IH / f < 3.8. Meeting the above conditions can achieve an ultra-large field angle and imaging range, and can achieve large image plane characteristics while ensuring the depth of field of the optical lens, thereby improving the imaging quality of the optical system.

[0057] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of view of the optical lens satisfy: 3 < TTL / IH < 3.3. Meeting the above conditions can better achieve the miniaturization of the lens. At the same time, when ensuring the same total length of the lens, it has a larger image plane and can match a larger-sized imaging chip to achieve high-definition imaging.

[0058] 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. Meeting the above conditions, and the second lens also uses a negative lens, which can further diverge light and increase the field angle of the imaging system.

[0059] 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; the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 2.4 < f4 / f < 3. Meeting the above conditions, the third and fourth lenses converge the incident light at the front end, which is beneficial to correcting the aberration and distortion of the edge field of view brought by the front lens group, making the lens have less distortion and capable of providing a high-definition imaging effect.

[0060] 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. Meeting the above conditions, the seventh lens has an appropriate negative focal length, which is beneficial to further increasing the imaging area of the optical lens, while balancing various aberrations generated by the front lens group and improving the imaging quality of the optical lens.

[0061] In some embodiments, the maximum field angle FOV of the optical lens and the true image height IH corresponding to the maximum field angle of view of the optical lens satisfy: 32° / mm < FOV / IH < 40° / mm. Meeting the above conditions, on the premise of meeting the image height requirements, it can ensure that the optical lens has a large field angle characteristic, so that the optical lens has good optical performance and can well capture the details of the photographed object.

[0062] 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. Meeting the above range is beneficial to achieving a balance between obtaining good imaging quality and an optical back focal length that is easy to assemble. While ensuring the imaging quality of the optical lens, it can avoid interference between the lens and other components and reduce the assembly process difficulty of the camera module.

[0063] In some embodiments, the curvature radius R1 of the object side surface of the first lens and the curvature radius R2 of the image side surface of the first lens satisfy: 2.6 < R1 / R2 < 3.5. Meeting the above conditions, the surface shape of the first lens can be reasonably set, enhancing the light collection ability of the first lens, so as to achieve an ultra-large field angle.

[0064] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 2.6 < R5 / R6 < 3.5. Meeting the above conditions, the third lens can balance the field curvature of the system and avoid deterioration of the edge image quality.

[0065] In some embodiments, the radius of curvature R9 of the object side surface of the fifth lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: 0.88 < R9 / R10 < 0.96; the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: 0.9 < R11 / R12 < 0.96. Meeting the above conditions, by reasonably setting the surface types of the fifth lens and the sixth lens, it is beneficial to the smooth transition of light, facilitating the correction of astigmatism and field curvature, improving the imaging quality of the optical lens, and ensuring the stability of the optical system.

[0066] In some embodiments, the radius of curvature R13 of the object side surface of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy: -5.5 < R13 / R14 < -4. Meeting the above range, the seventh lens is a biconcave lens. By reasonably setting the radius of curvature of the seventh lens, the aberration of the optical lens can be corrected, and the tolerance sensitivity of the optical lens can be reduced.

[0067] In some embodiments, the radius of curvature R15 of the object side surface of the eighth lens and the radius of curvature R16 of the image side surface of the eighth lens satisfy: -0.8 < R15 / R16 < -0.6. Meeting the above range, by reasonably limiting the surface type of the eighth lens, it helps the light to accurately focus on the imaging plane, improving the clarity and brightness uniformity of the image.

[0068] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 2 < (R5 + R6) / (R5 - R6) < 2.8. Meeting the above range, the light trend can be made smoother; at the same time, it can correct coma and field curvature, improve the flatness of imaging, and enhance the imaging quality of the optical lens.

[0069] In some embodiments, the radius of curvature R13 of the object side surface of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy: 0.6 < (R13 + R14) / (R13 - R14) < 0.7. Meeting the above range, by reasonably controlling the radius of curvature of the object side surface and the image side surface of the seventh lens, it is beneficial to control the shape of the seventh lens, correct the aberration generated by itself, and improve the imaging quality.

[0070] In some embodiments, the radius of curvature R15 of the object side surface of the eighth lens and the radius of curvature R16 of the image side surface of the eighth lens satisfy: -0.3 < (R15 + R16) / (R15 - R16) < -0.1. By satisfying the above range and reasonably defining the shapes of the object side surface and the image side surface of the eighth lens, the eighth lens can have an appropriate surface shape, which helps to control the light path of the marginal field of view and improve the imaging quality of the marginal field of view.

[0071] 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. By satisfying the above conditions, the ratio of the thickness of the third lens on the optical axis to the thickness of the fourth lens on the optical axis is reasonably configured, and the third lens and the fourth lens can regulate each other to maintain the characteristic of miniaturization of the optical system.

[0072] In some embodiments, the overall optical 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. By satisfying the above conditions, the overall length of the optical lens can be effectively compressed, and at the same time, it is beneficial to the structural design and production process of the optical lens.

[0073] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 2.7 mm < IH / Fno < 3.5 mm. By satisfying the above conditions, while maintaining a large image plane for the optical lens, a large aperture of the optical lens is ensured, achieving a balance between a large image plane and a large aperture.

[0074] In some embodiments, the sag SAG71 of the object side surface clear aperture radius, the sag SAG72 of the image side surface clear aperture radius of the seventh lens and the central thickness CT7 of the seventh lens satisfy: 1.5 < (SAG72 - SAG71) / CT7 < 1.7. By satisfying the above conditions, the surface shape of the object side surface of the seventh lens can be controlled, which is beneficial to the manufacturing and forming of the seventh lens and reduces the defective rate. In addition, it can also prevent the surface shape from being too curved and complex, making the system field curvature tend to be balanced. In some embodiments, the optical lens satisfies the conditional expressions: 16 mm < TTL < 18 mm, 1.4 mm < f < 1.7 mm, 195° < FOV < 210°, 5.3 mm < IH < 5.8 mm, 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. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least the following advantages: a relatively small total optical length; characteristics of a short focal length and a wide angle, where the depth of field of a short focal length lens is relatively deep, and both the front and back of the subject can remain relatively clear; an extremely large field of view angle, providing a wider shooting field of view for application scenarios such as vehicle surround-view lenses and capturing more image information; a relatively large imaging surface, which can be matched with a larger-sized chip to achieve high-definition imaging; a large aperture, enabling high-definition imaging even in complex light environments.

[0075] In some embodiments, the lens material of the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. Additionally, 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 of the optical lens provided by the present invention can adopt glass materials, and the second lens, the third lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt plastic materials. Adopting a glass-plastic hybrid structure can effectively reduce costs, correct aberrations, reduce the volume, improve the thermal stability performance, and provide an optical lens product with higher cost performance.

[0076] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving lens miniaturization. More specifically, the first lens and the fourth lens of the present invention adopt spherical lenses; the second lens, the third lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens adopt aspherical lenses.

[0077] In various embodiments of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations: ; where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, 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 surface coefficients of the fourth order, sixth order, eighth order, tenth order, and twelfth order, respectively.

[0078] The present invention is further illustrated below with reference to several embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens vary; for details, please refer to the parameter tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the present invention is not limited thereto. Any other changes, substitutions, combinations, or simplifications that do not deviate from the novelties of the present invention shall be considered equivalent replacements and are included within the scope of protection of the present invention.

[0079] Example 1 See also Figure 1 , shown is a schematic structural diagram of the optical lens 100 provided in Example 1 of the present invention, which includes, along the optical axis from the object side to the imaging surface, a first lens L1, a second lens L2, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0080] The first lens L1 has negative refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave; The second lens L2 has negative refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave; The third lens L3 has positive refractive power, its object-side surface S5 is concave, and its image-side surface S6 is convex; The fourth lens L4 has positive refractive power, its object-side surface S7 is convex, and its image-side surface S8 is convex; The fifth lens L5 has negative refractive power, its object-side surface S9 is concave, and its image-side surface S10 is convex; The sixth lens L6 has negative refractive power, its object-side surface S11 is concave, and its image-side surface S12 is convex; The seventh lens L7 has negative refractive power, its object-side surface S13 is concave, and its image-side surface S14 is concave; The eighth lens L8 has positive refractive power, its object-side surface S15 is convex, and its image-side surface S16 is convex; The object-side surface S17 and the image-side surface S18 of the filter G1 are both flat surfaces; The imaging surface S19 is a plane.

[0081] 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.

[0082] The relevant parameters of each lens in the optical lens in Example 1 are shown in Table 1-1.

[0083] Table 1-1 The surface parameters of the aspheric lens of the optical lens in Example 1 are shown in Table 1-2.

[0084] Table 1-2 In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown as follows: Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 shown.

[0085] Figure 2 The field curvature curve for Example 1 shows the degree of light curvature in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: degrees). As can be seen from the figure, the field curvature in the meridional and sagittal image planes is controlled within -0.05mm to 0.1mm, indicating that the optical lens can effectively correct for field curvature.

[0086] Figure 3 The F-Theta distortion curve for Example 1 is shown, representing the F-Theta distortion of light 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 of view angle (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within -1.2% to 3%, indicating that the optical lens is capable of correcting distortion well.

[0087] Figure 4 The following graph shows the axial aberration curve for Example 1, which represents the aberration on the optical axis at the imaging plane for 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 graph, the offset of the axial aberration is controlled within a range of -0.01mm to 0.02mm, indicating that the optical lens can effectively correct axial aberration.

[0088] Figure 5 The vertical chromatic aberration curve for Example 1 is shown. It plots the chromatic aberration of each wavelength relative to the center wavelength (0.555 μm) at different image heights on the imaging plane. The horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the graph, the vertical chromatic aberration for both the longest and shortest wavelengths is controlled within a range of -4 μm to 6 μm, demonstrating that this optical lens is capable of excellent chromatic aberration correction.

[0089] Example 2 See also Figure 6, shown is a schematic structural diagram of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, this embodiment is different in that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0090] The relevant parameters of each lens in the optical lens in Example 2 are shown in Table 2-1.

[0091] Table 2-1 The surface parameters of the aspheric lens of the optical lens in Example 2 are shown in Table 2-2.

[0092] Table 2-2 In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown as follows: Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 shown.

[0093] Figure 7 The field curvature curve for Example 2 shows the degree of light curvature in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: degrees). As can be seen from the figure, the field curvature in the meridional and sagittal image planes is controlled within a range of -0.05mm to 0.05mm, indicating that the optical lens can effectively correct for field curvature.

[0094] Figure 8 The F-Theta distortion curve for Example 2 is shown, representing the F-Theta distortion of light 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 of view angle (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within -1.2% to 3%, indicating that the optical lens is capable of correcting distortion well.

[0095] Figure 9 The following graph shows the axial aberration curve for Example 2, which represents the aberration on the optical axis at the imaging plane for 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 graph, the offset of the axial aberration is controlled within a range of -0.01mm to 0.02mm, indicating that the optical lens can effectively correct axial aberration.

[0096] Figure 10The vertical chromatic aberration curve for Example 2 is shown. It plots the chromatic aberration of each wavelength relative to the center wavelength (0.555 μm) at different image heights on the imaging plane. The horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the graph, the vertical chromatic aberration for both the longest and shortest wavelengths is controlled within a range of -4 μm to 6 μm, demonstrating that this optical lens is capable of excellent chromatic aberration correction.

[0097] Example 3 See also Figure 11 , shown is a schematic structural diagram of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, this embodiment is different in that: the object-side surface S7 of the fourth lens L4 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0098] The relevant parameters of each lens in the optical lens in Example 3 are shown in Table 3-1.

[0099] Table 3-1 The surface parameters of the aspheric lens of the optical lens in Example 3 are shown in Table 3-2.

[0100] Table 3-2 In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown as follows: Figure 12 、 Figure 13 、 Figure 14 、 Figure 15 shown.

[0101] Figure 12 The field curvature curve for Example 3 shows the degree of light curvature in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: degrees). As can be seen from the figure, the field curvature in the meridional and sagittal image planes is controlled within a range of -0.15mm to 0.05mm, demonstrating that the optical lens is able to effectively correct for field curvature.

[0102] Figure 13 The F-Theta distortion curve for Example 3 is shown, representing the F-Theta distortion of light 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 of view angle (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within 0-3%, indicating that the optical lens is capable of correcting distortion well.

[0103] Figure 14The following graph shows the axial aberration curve for Example 3, which represents the aberration on the optical axis at the imaging plane for 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 graph, the offset of the axial aberration is controlled within a range of -0.01mm to 0.02mm, indicating that the optical lens can effectively correct axial aberration.

[0104] Figure 15 The vertical chromatic aberration curve for Example 3 is shown. It plots the chromatic aberration of each wavelength relative to the center wavelength (0.555 μm) at different image heights on the imaging plane. The horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the graph, the vertical chromatic aberration for both the longest and shortest wavelengths is controlled within a range of -4 μm to 6 μm, demonstrating that this optical lens is capable of excellent chromatic aberration correction.

[0105] Please refer to Table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, real image height IH corresponding to the maximum field of view angle, chief ray incidence angle CRA at the maximum image height, and maximum field of view angle FOV of the optical lens, as well as the numerical values corresponding to each conditional expression in each embodiment.

[0106] Table 4 In summary, the optical lens provided by the present invention uses eight lenses with specific optical powers. Through the combination of specific surface shapes and reasonable optical power distribution, it is possible to improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, so that the lens has one or more advantages such as large aperture, short focus, ultra-large field of view, small distortion, and high imaging quality.

[0107] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0108] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An optical lens, comprising eight lenses, characterized in that: Along the optical axis from the object side to the imaging surface, it includes: a first lens having negative optical power, wherein the object-side surface is convex and the image-side surface is concave; a second lens having negative optical power, the object-side surface of which is convex and the image-side surface of which is concave; a third lens element having positive optical power, whose object-side surface is concave and whose image-side surface is convex; a fourth lens element having positive refractive power and a convex image-side surface; a fifth lens element having negative optical power, whose object-side surface is concave and whose image-side surface is convex; a sixth lens element having negative optical power, whose object-side surface is concave and whose image-side surface is convex; a seventh lens element having negative optical power, whose object-side surface and image-side surface are concave; an eighth lens element having positive refractive power, whose object-side surface is convex and whose image-side surface is convex; The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: <f1 / f<-4。 2. The optical lens according to 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。 3. The optical lens according to claim 1, wherein: The maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens meet the following requirements: 105° <FOV / Fno<120°。 4. The optical lens according to claim 1, wherein: The object side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: <R13 / f<-5.5。 5. The optical lens according to claim 1, wherein: The focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: <f1 / f8<-2.2。 6. The optical lens according to 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 center thickness CT6 of the sixth lens satisfy the following conditions: 0.38<(CT56+CT67+C78) / CT6<0.

5.

7. The optical lens according to claim 1, wherein: The object side light semi-aperture DM11 of the first lens and the image side light semi-aperture DM82 of the eighth lens meet the following conditions: 2.8 <DM11 / DM82<3.6。 8. The optical lens according to claim 1, wherein: 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 arc value θ of the maximum half field angle of the optical lens satisfy the following conditions: 0.99<(IH / 2) / (f×θ)<1.

01.

9. The optical lens according to claim 1, wherein: The true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens meet the following requirements: 5.5 <IH / EPD<7.2。 10. The optical lens according to claim 1, wherein: The object side light semi-aperture sag height SAG81 of the eighth lens, the image side light semi-aperture sag height SAG82 of the eighth lens and the center thickness CT8 of the eighth lens satisfy: -0.7<(SAG82-SAG81) / CT8<-0.6.

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