Optical lens

Abstract

The invention provides an optical lens, which consists of eight lenses, and sequentially comprises 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 from an object side to an imaging surface, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the third lens has positive focal power; the fourth lens has negative focal power; the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface; the object side surface of the sixth lens is a concave surface, and the image side surface of the sixth lens is a 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 convex surface; and the eighth lens has negative focal power. According to the optical lens provided by the invention, through specific surface shape matching and reasonable focal power distribution, the imaging quality of the optical lens can be improved, and the lens has one or more advantages of large field angle, large aperture, high imaging quality and the like.

Description

TECHNICAL FIELD

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

[0002] The law enforcement instrument is mainly used for digital recording of the scene in the law enforcement process, such as video shooting, photographing, audio recording, etc., so as to provide effective scene image data afterwards. In the process of on-site law enforcement, law enforcement personnel need to record a larger range and clear image, however, the lens of the law enforcement instrument on the market either records unclear images or has too small a field of view and cannot record too many pictures.

[0003] Therefore, how to make the lens of the law enforcement instrument meet high imaging quality is a problem to be solved at present. SUMMARY

[0004] In view of the above problems, the purpose of the present application is to provide an optical lens, which has the advantages of excellent imaging quality.

[0005] The technical scheme adopted by the present application is:

[0006] An optical lens is composed of eight lenses, which includes, along the optical axis from the object side to the imaging surface:

[0007] A first lens with negative focal power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface;

[0008] A second lens with negative focal power, the object side surface of which is a concave surface, and the image side surface of which is a convex surface;

[0009] A third lens with positive focal power;

[0010] A fourth lens with negative focal power;

[0011] A fifth lens with positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface;

[0012] A sixth lens with negative focal power, the object side surface of which is a concave surface, and the image side surface of which is a convex surface;

[0013] A seventh lens with positive focal power, the object side surface of which is a concave surface, and the image side surface of which is a convex surface;

[0014] An eighth lens with negative focal power;

[0015] Wherein, the object side surface curvature radius R3 of the second lens and the image side surface curvature radius R4 of the second lens satisfy: -0.7<(R3-R4) / (R3+R4)<-0.3, and the object side surface curvature radius R13 of the seventh lens and the image side surface curvature radius R14 of the seventh lens satisfy: 0.4<(R13-R14) / (R13+R14)<1.

[0016] Further preferably, the total track length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5 < TTL / f < 10; the total track length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.5 < TTL / IH < 3.8.

[0017] Further preferably, the maximum field angle FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 50° < FOV / FNO < 85°; 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: 3.7 < IH / EPD < 5.8.

[0018] Further preferably, the real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.9 < IH / f < 2.9; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1 < BFL / f < 2.

[0019] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.6 < f1 / f < -1.4, the effective focal length f of the optical lens and the radius of curvature R1 of the object side surface of the first lens satisfy: 3.2 < R1 / f < 10, the effective focal length f of the optical lens and the radius of curvature R2 of the image side surface of the first lens satisfy: 0.75 < R2 / f < 1.6.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -14 < f2 / f < -5.7, the effective focal length f of the optical lens and the radius of curvature R3 of the object side surface of the second lens satisfy: -4.6 < R3 / f < -3.1, the effective focal length f of the optical lens and the radius of curvature R4 of the image side surface of the second lens satisfy: -15 < R4 / f < -8.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1 < f5 / f < 1.5; the effective focal length f of the optical lens and the radius of curvature R9 of the object side surface of the fifth lens satisfy: 1 < R9 / f < 3.2; the effective focal length f of the optical lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: -1.8 < R10 / f < -0.9.

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -6 < f6 / f < -1.5; the object-side curvature radius R11 of the sixth lens and the image-side curvature radius R12 of the sixth lens satisfy: -1 < (R11 - R12) / (R11 + R12) < -0.5.

[0023] Further preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 2 < f7 / f < 3; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -50 < R13 / f < -3.4; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.7 < R14 / f < -1.

[0024] Further preferably, the combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 1.5 < f45678 / f < 3; the object-side clear aperture radius d1 of the first lens and the image-side clear aperture radius d16 of the eighth lens satisfy: 1.3 < d1 / d16 < 4.

[0025] Compared with the prior art, the optical lens provided by the present invention adopts eight lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power distributions, it can improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, enabling the lens to have one or more advantages such as a large field angle, a large aperture, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, in which:

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

[0028] Figure 2 is a graph of F-Tan(Theta) distortion of the optical lens in Embodiment 1 of the present invention.

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

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

[0031] Figure 5 is a MTF graph of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 6 Relative illuminance curve of the optical lens in Embodiment 1 of the present application.

[0033] Figure 7 Structural schematic diagram of the optical lens in Embodiment 2 of the present application.

[0034] Figure 8 F-Tan(Theta) distortion curve of the optical lens in Embodiment 2 of the present application.

[0035] Figure 9 Axial aberration curve of the optical lens in Embodiment 2 of the present application.

[0036] Figure 10 Decentration curve of the optical lens in Embodiment 2 of the present application.

[0037] Figure 11 MTF curve of the optical lens in Embodiment 2 of the present application.

[0038] Figure 12 Relative illuminance curve of the optical lens in Embodiment 2 of the present application.

[0039] Figure 13 Structural schematic diagram of the optical lens in Embodiment 3 of the present application.

[0040] Figure 14 F-Tan(Theta) distortion curve of the optical lens in Embodiment 3 of the present application.

[0041] Figure 15 Axial aberration curve of the optical lens in Embodiment 3 of the present application.

[0042] Figure 16 Decentration curve of the optical lens in Embodiment 3 of the present application.

[0043] Figure 17 MTF curve of the optical lens in Embodiment 3 of the present application.

[0044] Figure 18 Relative illuminance curve of the optical lens in Embodiment 3 of the present application.

[0045] Figure 19 Structural schematic diagram of the optical lens in Embodiment 4 of the present application.

[0046] Figure 20 F-Tan(Theta) distortion curve of the optical lens in Embodiment 4 of the present application.

[0047] Figure 21 Axial aberration curve of the optical lens in Embodiment 4 of the present application.

[0048] Figure 22 A graph of the lateral chromatic aberration curve of the optical lens in Embodiment 4 of the present application.

[0049] Figure 23 A graph of the MTF curve of the optical lens in Embodiment 4 of the present application.

[0050] Figure 24 A graph of the relative luminance curve of the optical lens in Embodiment 4 of the present application.

[0051] The following detailed description will further describe the present application with reference to the above-mentioned drawings. DETAILED DESCRIPTION

[0052] For a better understanding of the present application, various aspects of the present application will be described in more detail 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 drawing reference numerals refer to like elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0053] It is to be noted that, in the present specification, the expressions first, second, third and the like 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 the second lens or the third lens without departing from the teachings of the present application.

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

[0055] In the present 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.

[0056] It should also be understood that the use of the terms "have", "has", "having", "include", "includes", "including", "comprise", "comprises" and / or "comprising", when appearing in the specification, is taken as referring to the existence of the stated features, elements and / or components, but does not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. Further, when referring to the list of features, the expression "at least one of" is intended to mean "one or more of the listed features". Furthermore, when describing the embodiments of the present application, the use of "can" means "one or more embodiments of the present application". Also, the use of the term "exemplary" is intended to present an example or an illustration.

[0057] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It 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.

[0058] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other if there is no conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0059] The optical lens provided by the embodiments of the present application is composed of eight lenses, which are sequentially arranged along the optical axis from the object side to the imaging surface as 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.

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

[0061] In some embodiments, the optical lens can further include a diaphragm, which can be located between the third lens and the fourth lens. It can be understood that the diaphragm can be used to limit the amount of light to change the brightness of the imaging.

[0062] In some embodiments, the optical lens can further include a filter, which can be disposed between the eighth lens and the imaging surface. The filter is used to filter out interference light, preventing the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0063] In some embodiments, the sixth lens and the seventh lens can be cemented together to form a cemented lens, which can effectively correct chromatic aberration of the optical lens, reduce the sensitivity of the optical lens to decentration, balance aberration of the optical lens, and improve the imaging quality of the optical lens. In addition, the cemented lens can reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0064] In some embodiments, the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy -0.7 < (R3-R4) / (R3+R4) < -0.3, and 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 0.4 < (R13-R14) / (R13+R14) < 1. Satisfying the above ranges can correct the aberration of the optical lens, ensure smooth light ray trend through the second and seventh lenses, reduce the tolerance sensitivity of the optical lens, and facilitate smooth entry of light rays into the rear end lens. More specifically, -0.61 < (R3-R4) / (R3+R4) < -0.38, and 0.52 < (R13-R14) / (R13+R14) < 0.94.

[0065] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy 5 < TTL / f < 10, and the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy 2.5 < TTL / IH < 3.8. Satisfying the above ranges helps to achieve a balance between the total length and the volume of the optical lens by reasonably controlling the total length, focal length, and image height of the optical lens, and is conducive to improving the structural stability of the optical lens. More specifically, 5.57 < TTL / f < 9.04, and 2.73 < TTL / IH < 3.46.

[0066] In some embodiments, the maximum field angle FOV of the optical lens and the aperture value FNO of the optical lens satisfy 50° < FOV / FNO < 85°, and 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 3.7 < IH / EPD < 5.8. Satisfying the above ranges helps to achieve the characteristics of a large field angle and a large aperture of the optical lens, and is conducive to increasing the light quantity and improving the relative luminance. More specifically, 54° < FOV / FNO < 81°, and 4.06 < IH / EPD < 5.31.

[0067] In some embodiments, a real image height IH corresponding to a maximum field of view angle of the optical lens satisfies: 1.9 < IH / f < 2.9, and a back focal length BFL of the optical lens satisfies: 1 < BFL / f < 2, where f is an effective focal length of the optical lens. Satisfying the above ranges can reasonably control the image height, focal length and back focal length of the optical lens, and under the condition that the focal length is fixed, the optical lens can have a large target surface and a long back focal length. The large target surface can help improve the imaging quality of the optical lens, and the long back focal length can meet the arrangement requirements of the rear-end chip and reduce the assembly and processing difficulty. More specifically, 2.03 < IH / f < 2.66, and 1.08 < BFL / f < 1.83.

[0068] In some embodiments, an effective focal length f of the optical lens satisfies: -2.6 < f1 / f < -1.4, a radius of curvature R1 of an object side surface of the first lens satisfies: 3.2 < R1 / f < 10, and a radius of curvature R2 of an image side surface of the first lens satisfies: 0.75 < R2 / f < 1.6. Satisfying the above ranges can make the first lens have a suitable negative focal length and a reasonable surface type arrangement, which can help collect as much light as possible in a large field of view angle into the optical lens, obtain more picture information, and control the trend of the edge large-angle light, thereby improving the imaging quality of the optical lens. More specifically, -2.39 < f1 / f < -1.52, 3.57 < R1 / f < 9.42, and 0.82 < R2 / f < 1.5.

[0069] In some embodiments, an effective focal length f of the optical lens satisfies: -14 < f2 / f < -5.7, a radius of curvature R3 of an object side surface of the second lens satisfies: -4.6 < R3 / f < -3.1, and a radius of curvature R4 of an image side surface of the second lens satisfies: -15 < R4 / f < -8. Satisfying the above ranges can make the second lens have a suitable negative focal length and a reasonable surface type arrangement, which can help the diverging light to enter the rear-end lenses smoothly, and make the light trend smooth. More specifically, -12.67 < f2 / f < -6.34, -4.22 < R3 / f < -3.43, and -14.08 < R4 / f < -8.94.

[0070] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1 < f5 / f < 1.5; the effective focal length f of the optical lens and the object-side surface curvature radius R9 of the fifth lens satisfy: 1 < R9 / f < 3.2; and the effective focal length f of the optical lens and the image-side surface curvature radius R10 of the fifth lens satisfy: -1.8 < R10 / f < -0.9. Satisfying the above ranges, by reasonably controlling the focal length proportion and surface shape of the fifth lens, the light ray trend of the front end lens is gently corrected, the aberration generated by the front end lens is corrected, and the imaging quality is improved. More specifically, 1.15 < f5 / f < 1.33; 1.05 < R9 / f < 2.98; and -1.64 < R10 / f < -0.97.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -6 < f6 / f < -1.5; the object-side surface curvature radius R11 of the sixth lens and the image-side surface curvature radius R12 of the sixth lens satisfy: -1 < (R11-R12) / (R11+R12) < -0.5; the object-side surface curvature radius R11 of the sixth lens and the effective focal length f of the optical lens satisfy: -4 < R11 / f < -0.9; and the image-side surface curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: -50 < R12 / f < -3.4. Satisfying the above ranges, by reasonably setting the focal length and surface shape of the sixth lens, the aberration of the edge field of view can be effectively improved, and the overall imaging quality of the optical lens is improved. More specifically, -5.5 < f6 / f < -1.68; -0.9 < (R11-R12) / (R11+R12) < -0.57; -3.68 < R11 / f < -0.98; and -45.72 < R12 / f < -3.76.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 2 < f7 / f < 3; the object-side surface curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -50 < R13 / f < -3.4; and the image-side surface curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.7 < R14 / f < -1. Satisfying the above ranges, by reasonably setting the focal length and surface shape of the seventh lens, the chromatic aberration of the system can be better corrected in cooperation with the sixth lens, and the overall imaging quality is improved. More specifically, 2.12 < f7 / f < 2.71; -45.72 < R13 / f < -3.76; and -1.59 < R14 / f < -1.16.

[0073] In some embodiments, a combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and an effective focal length f of the optical lens satisfy: 1.5 < f45678 / f < 3. By satisfying the above range, by reasonably setting the positive refractive power of the stop rear lens group, the distortion and the astigmatism generated by the front end lens of the optical lens are balanced, and the imaging quality of the optical lens is improved. More specifically, 1.69 < f45678 / f < 2.74.

[0074] In some embodiments, a half-aperture radius d1 of the object side surface of the first lens and a half-aperture radius d16 of the image side surface of the eighth lens satisfy: 1.3 < d1 / d16 < 4. By satisfying the above range, by controlling the aperture ratio of the front and rear lenses, the light ray trend is limited within a reasonable range, and the imaging surface illuminance is uniform. More specifically, 1.41 < d1 / d16 < 3.87.

[0075] In some embodiments, an effective focal length f of the optical lens, a maximum field of view FOV of the optical lens and a real image height IH corresponding to the maximum field of view of the optical lens satisfy: 50° < f x FOV / IH < 75°. By satisfying the above range, by reasonably limiting the relationship among the focal length, the field of view and the image height of the optical lens, the balance between the large field of view and the large target surface imaging of the optical lens is realized. More specifically, 53.9° < f x FOV / IH < 69.77°.

[0076] In some embodiments, a half-aperture radius d1 of the object side surface of the first lens, a real image height IH corresponding to the maximum field of view of the optical lens and a maximum field of view FOV of the optical lens satisfy: 0.2 < d1 / (IH / 2) / tan(FOV / 2) < 0.9. By satisfying the above range, the front end aperture can be small while the optical lens has a large field of view and a large image surface. More specifically, 0.24 < d1 / (IH / 2) / tan(FOV / 2) < 0.86.

[0077] In some embodiments, an effective focal length f of the optical lens and a focal length f3 of the third lens satisfy: 2.2 < f3 / f < 3.6. By satisfying the above range, the third lens has a suitable positive refractive power, which is helpful for light convergence, and the lens shape is gentle, which is conducive to reducing the volume and reducing the cost. More specifically, 2.45 < f3 / f < 3.34.

[0078] In some embodiments, an effective focal length f of the optical lens and a focal length f4 of the fourth lens satisfy: -7.8 < f4 / f < -2. By satisfying the above range, by reasonably controlling the focal length ratio of the fourth lens, the light rays emitted through the front end lens are collected, and the collected light rays smoothly enter the rear lenses, and the resolving power of the optical lens is improved. More specifically, -7.14 < f4 / f < -2.19.

[0079] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -14 < f8 / f < -2.8. By reasonably controlling the focal length ratio of the eighth lens, the light rays to the image plane are smoothly controlled to obtain a large target surface, and the optical lens is ensured to have high resolving power on the basis of eliminating ghost images, thereby improving the imaging quality of the optical lens. More specifically, -12.85 < f8 / f < -3.08.

[0080] In some embodiments, the optical lens satisfies the condition: 2mm < f < 3mm, 1mm < EPD < 1.6mm, 15mm < TTL < 21mm, 1.8 < FNO < 2.2, 19° < CRA < 22°, 3mm < BFL < 4.2mm, 100° < FOV < 170°, 5.5mm < IH < 6mm; wherein f represents the effective focal length of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, FNO represents the aperture value of the optical lens, CRA represents the chief ray angle of incidence at the maximum image height of the optical lens, BFL represents the back focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, and IH represents the real image height corresponding to the maximum field of view angle of the optical lens. Satisfying the above conditions indicates that the optical lens provided by the embodiments of the present application at least has the characteristics of a large field of view angle, a large aperture, high imaging quality, and the like. More specifically, 2.18mm < f < 2.86mm, 1.08mm < EPD < 1.43mm, 15.89mm < TTL < 20.01mm, 1.9 < FNO < 2.1, 19.65° < CRA < 21.72°, 3.08mm < BFL < 4mm, 109° < FOV < 161°, 5.79mm < IH < 5.81mm.

[0081] 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 characteristics of the glass itself. In the optical lens provided by the present application, the first lens, the second lens, the fifth lens, the sixth lens, and the seventh lens are glass lenses, and the third lens, the fourth lens, and the eighth lens are plastic lenses.

[0082] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens can adopt a spherical lens or an aspherical lens. Compared with a spherical structure, an aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving the miniaturization of the lens. More specifically, the third lens, the fourth lens, the fifth lens and the eighth lens of the present application adopt an aspherical lens, and the first lens, the second lens, the sixth lens and the seventh lens adopt a spherical lens.

[0083] In various embodiments of the present application, when the lens adopts an aspherical lens, the shape of each aspherical surface of the optical lens satisfies the following equation:

[0084]

[0085] wherein z is the distance of the curved surface from the vertex of the curved surface in the direction of the optical axis, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the quadratic surface coefficient, and B, C, D, E, F, G and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order and sixteenth-order surface coefficients, respectively.

[0086] The present application will be further described in the following embodiments. In various embodiments, the thickness, the radius of curvature and the material selection of each lens in the optical lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present application, but the embodiments of the present application are not limited to the following embodiments only, and any changes, substitutions, combinations or simplifications made without departing from the innovative points of the present application should be regarded as equivalent replacement modes, and are included in the protection scope of the present application.

[0087] Embodiment 1

[0088] 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 diaphragm 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.

[0089] 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.

[0090] The second lens L2 has a negative focal power, the object side surface S3 thereof is a concave surface, and the image side surface S4 thereof is a convex surface.

[0091] The third lens L3 has a positive focal power, the object side surface S5 thereof is a convex surface, and the image side surface S6 thereof is a convex surface.

[0092] The fourth lens L4 has negative focal power, the object side S7 is a concave surface, and the image side S8 is a convex surface;

[0093] The fifth lens L5 has positive focal power, the object side S9 is a convex surface, and the image side S10 is a convex surface;

[0094] The sixth lens L6 has negative focal power, the object side S11 is a concave surface, and the image side is a convex surface;

[0095] The seventh lens L7 has positive focal power, the object side is a concave surface, and the image side S13 is a convex surface;

[0096] The sixth lens L6 and the seventh lens L7 form a cemented lens group with negative focal power, that is, the cemented surface of the image side of the sixth lens L6 and the object side of the seventh lens L7 is S13;

[0097] The eighth lens L8 has negative focal power, the object side S14 is a convex surface, and the image side S15 is a concave surface.

[0098] The object side S16 and the image side S17 of the filter G1 are both flat surfaces;

[0099] The imaging surface S18 is a flat surface.

[0100] The first lens L1, the second lens L2, the sixth lens L6, and the seventh lens L7 are all glass spherical lenses, the fifth lens L5 is a glass aspherical lens, and the third lens L3, the fourth lens L4, and the eighth lens L8 are all plastic aspherical lenses.

[0101] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0102] Table 1-1

[0103]

[0104] The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0105] Table 1-2

[0106] Face number K B C D E F G H S5 1.24E+01 5.79E-03 -1.06E-03 1.16E-03 -5.77E-04 2.62E-04 -1.06E-04 1.76E-05 S6 -2.00E+02 1.05E-02 7.53E-03 -9.01E-03 5.80E-03 -1.42E-03 -1.62E-04 8.77E-05 S7 -7.46E+01 2.66E-02 -1.15E-02 4.79E-03 -1.06E-03 -2.27E-04 1.68E-04 -2.61E-05 S8 -6.84E+02 -5.73E-03 2.23E-03 -7.76E-04 2.92E-05 7.12E-05 8.35E-07 -3.68E-06 S9 -7.04E+00 1.57E-03 1.18E-04 -2.74E-04 6.34E-05 -2.43E-06 0.00E+00 0.00E+00 S10 -7.80E-02 -8.66E-03 2.85E-03 -3.39E-04 -9.51E-06 6.83E-06 0.00E+00 0.00E+00 S14 -1.99E+00 -1.75E-02 -1.74E-04 -3.09E-05 6.34E-06 6.87E-07 -3.34E-08 -1.36E-08 S15 -1.61E+00 -1.40E-02 -1.05E-04 1.85E-04 -8.25E-06 -1.98E-06 3.29E-07 -1.71E-08

[0107] Figure 2 The F-Tan(Theta) distortion curve of the optical lens 100 in this embodiment is shown, which represents the distortion of different field angles on the imaging surface. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, as the field angle increases, the change of the distortion value is relatively stable, which shows that the optical lens 100 can correct the distortion well.

[0108] Figure 3 The axial aberration curve of the optical lens 100 in the embodiment is shown, which represents the axial aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the shift of the axial aberration is controlled within-0.02mm-0.04mm, which shows that the optical lens 100 can better correct the axial aberration.

[0109] Figure 4 The curve of the optical lens 100 in the embodiment is shown, which represents the color difference of each wavelength at different image heights on the imaging surface relative to the central wavelength (0.555μm), the horizontal axis represents the color difference value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the figure, the color difference of the longest wavelength and the shortest wavelength is controlled within-1μm-3μm, which shows that the optical lens 100 can better correct the color difference.

[0110] Figure 5 The modulation transfer function (MTF) curve of the optical lens 100 in the embodiment is shown, which represents the lens imaging modulation degree of different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the embodiment is above 0.4 in the full field of view, and the MTF curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in the case of low frequency and high frequency.

[0111] Figure 6 The relative luminance curve of the optical lens 100 in the embodiment is shown, which represents the relative luminance value of different field angles on the imaging surface, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative luminance (unit: %). As can be seen from the figure, the relative luminance value of the optical lens is still greater than 60% at the maximum half field angle, which shows that the optical lens has good relative luminance.

[0112] Embodiment 2

[0113] Please refer to Figure 7 , which is a structural schematic diagram of the optical lens 200 provided in the embodiment 2 of the present application. Compared with the embodiment 1, the main difference is that the sixth lens L6 and the seventh lens L7 form a cemented lens group with positive focal power; the image side surface S6 of the third lens L3 is a concave surface; the object side surface S7 of the fourth lens L4 is a convex surface; the image side surface S8 of the fourth lens L4 is a concave surface; the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0114] The related parameters of each lens in the optical lens 200 in the embodiment 2 are shown in Table 2-1.

[0115] Table 2-1

[0116]

[0117]

[0118] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0119] Table 2-2

[0120] Face number K B C D E F G H S5 1.83E-01 6.45E-03 3.56E-04 1.45E-03 -1.12E-03 5.77E-04 -1.46E-04 1.59E-05 S6 5.50E+01 2.67E-02 -1.49E-02 1.82E-02 -4.85E-03 -4.59E-03 3.64E-03 -7.05E-04 S7 -4.19E+02 -3.11E-03 -1.20E-02 5.59E-03 -1.50E-03 -4.66E-04 8.40E-05 4.48E-05 S8 -7.61E+00 -3.63E-03 2.72E-03 -1.46E-03 -1.62E-04 6.60E-05 2.44E-05 -5.68E-06 S9 -2.77E+01 -5.50E-03 3.33E-04 5.79E-05 2.28E-05 -7.14E-06 0.00E+00 0.00E+00 S10 -2.26E-01 -7.12E-03 -3.69E-05 -4.32E-05 -5.77E-05 1.08E-05 0.00E+00 0.00E+00 S14 7.92E+03 -1.39E-02 5.06E-04 2.54E-06 1.91E-05 -7.77E-06 1.08E-06 -6.23E-08 S15 6.49E-01 -1.24E-02 6.62E-04 1.31E-05 -6.43E-06 -3.15E-07 9.50E-08 -3.49E-09

[0121] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination diagram of the optical lens 200 are respectively as follows: Figure 8 to Figure 12 As shown.

[0122] from Figure 8 As can be seen, the distortion value changes relatively smoothly as the field of view increases, indicating that the optical lens 200 can correct distortion well.

[0123] from Figure 9 As can be seen, the axial aberration offset is controlled within -0.04mm to 0.04mm, indicating that the optical lens 200 can effectively correct axial aberration.

[0124] from Figure 10 As can be seen, the chromatic aberration of the longest and shortest wavelengths is controlled within -1μm to 4μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0125] from Figure 11 As can be seen, the MTF value of this embodiment is above 0.38 throughout the entire field of view. The MTF curve decreases smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0126] from Figure 12 As can be seen, the relative illumination value of the optical lens is still greater than 85% at the maximum half field of view, indicating that the optical lens 200 has good relative illumination.

[0127] Example 3

[0128] Please see Figure 13, which is a structural schematic view of the optical lens 300 provided in the embodiment 3 of the present application. Compared with the embodiment 1, the main difference is that the sixth lens L6 and the seventh lens L7 form a cemented lens group with positive focal power; the object side S5 of the third lens L3 is a concave surface; the image side S8 of the fourth lens L4 is a concave surface; the object side S14 of the eighth lens L8 is a concave surface; the image side S15 of the eighth lens L8 is a convex surface; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0129] The related parameters of each lens in the optical lens 300 in the embodiment 3 are shown in Table 3-1.

[0130] Table 3-1

[0131]

[0132]

[0133] The surface type parameters of the aspheric lens of the optical lens 300 in the embodiment 3 are shown in Table 3-2.

[0134] Table 3-2

[0135] Face number K B C D E F G H S5 7.23E+02 -2.65E-03 -1.00E-03 4.75E-04 -1.96E-04 2.43E-04 -1.30E-04 2.08E-05 S6 -1.19E+01 -8.71E-03 6.68E-03 -8.82E-03 6.67E-03 -2.54E-03 4.06E-04 -1.46E-05 S7 -1.54E+02 1.22E-03 -8.38E-03 4.19E-03 -1.26E-03 -5.35E-04 2.89E-04 -2.61E-05 S8 -1.22E+01 -4.81E-03 2.12E-04 -3.84E-04 -5.61E-05 8.99E-06 -2.60E-05 7.11E-06 S9 -1.21E+01 1.54E-03 4.64E-04 -1.84E-04 -4.54E-05 1.18E-05 0.00E+00 0.00E+00 S10 1.61E+00 6.19E-03 -3.50E-04 -9.37E-05 6.33E-05 1.60E-05 0.00E+00 0.00E+00 S14 2.96E+00 -1.12E-02 8.81E-04 1.47E-04 7.89E-05 -2.63E-06 -2.43E-06 6.01E-07 S15 7.82E+01 -1.09E-02 1.63E-03 1.96E-04 5.69E-06 -1.98E-06 -7.01E-07 1.73E-07

[0136] In the embodiment, the F-Tan(Theta) distortion curve, the axial aberration curve, the transverse chromatic aberration curve, the MTF curve and the relative illumination diagram of the optical lens 300 are respectively shown in Figure 14 to Figure 18

[0137] As can be seen from Figure 14 , the change of the distortion value is relatively stable with the increase of the field angle, which indicates that the optical lens 300 can better correct the distortion.

[0138] As can be seen from Figure 15 , the shift amount of the axial aberration is controlled within-0.02mm-0.05mm, which indicates that the optical lens 300 can better correct the axial aberration.

[0139] As can be seen from Figure 16 , the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within-1um-4um, which indicates that the optical lens 300 can better correct the chromatic aberration.

[0140] As can be seen from Figure 17 , the MTF value of the embodiment is above 0.38 in the full field of view, and the MTF curve is uniformly and smoothly decreased from the center to the edge of the field of view, which has better imaging quality and better detail resolution ability in the low frequency and high frequency cases.

[0141] As can be seen from Figure 18 ​As can be seen, the relative illumination value of the optical lens is still greater than 60% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0142] Example 4

[0143] Please see Figure 19 The diagram shows a schematic of the optical lens 400 provided in Embodiment 4 of the present invention. The main differences between this embodiment and Embodiment 1 are: the sixth lens L6 and the seventh lens L7 form a cemented lens group with positive optical power; the object side S5 of the third lens L3 is concave; the image side S8 of the fourth lens L4 is concave; the object side S14 of the eighth lens L8 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0144] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0145] Table 4-1

[0146]

[0147] The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0148] Table 4-2

[0149] Face number K B C D E F G H S5 5.61E+02 -1.52E-03 -6.52E-04 4.69E-04 -1.91E-04 2.46E-04 -1.31E-04 2.00E-05 S6 -1.20E+01 -8.46E-03 6.85E-03 -8.78E-03 6.69E-03 -2.52E-03 4.09E-04 -1.85E-05 S7 -3.17E+02 1.38E-03 -8.23E-03 4.25E-03 -1.24E-03 -5.34E-04 2.86E-04 -2.65E-05 S8 -1.12E+01 -4.34E-03 2.79E-04 -3.85E-04 -5.49E-05 1.08E-05 -2.58E-05 6.59E-06 S9 -1.23E+01 1.42E-03 4.60E-04 -1.82E-04 -4.83E-05 9.73E-06 0.00E+00 0.00E+00 S10 1.61E+00 6.26E-03 -3.36E-04 -9.43E-05 6.12E-05 1.56E-05 0.00E+00 0.00E+00 S14 2.89E+00 -1.15E-02 8.72E-04 1.54E-04 8.13E-05 -2.36E-06 -2.46E-06 5.92E-07 S15 -1.75E+04 -1.11E-02 1.62E-03 2.00E-04 5.99E-06 -1.88E-06 -6.52E-07 1.77E-07

[0150] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination diagram of the optical lens 400 are respectively as follows: Figure 20 to Figure 24 As shown.

[0151] from Figure 20 As can be seen, the distortion value changes relatively smoothly as the field of view increases, indicating that the optical lens 400 can correct distortion well.

[0152] from Figure 21 As can be seen, the axial aberration offset is controlled within -0.05mm to 0.04mm, indicating that the optical lens 400 can correct axial aberration well.

[0153] from Figure 22 As can be seen, the chromatic aberration of the longest and shortest wavelengths is controlled within -1μm to 4μm, indicating that the optical lens 400 can correct chromatic aberration well.

[0154] from Figure 23As can be seen from the MTF curves, the MTF values of the optical lens of the embodiment are all above 0.35 in the full field of view, and the MTF curves are uniformly and smoothly decreased from the central field of view to the edge field of view, and the optical lens has good imaging quality and good detail resolution capability in both low frequency and high frequency cases.

[0155] From Figure 24 As can be seen from the relative illumination curves, the relative illumination values of the optical lens are still greater than 60% at the maximum half field of view, which indicates that the optical lens has good relative illumination.

[0156] Referring to Table 5, the optical properties corresponding to the above embodiments are shown, including the effective focal length f, the total track length TTL, the aperture value FNO, the real image height IH corresponding to the maximum field of view, the chief ray angle of incidence CRA at the maximum image height, the maximum field of view FOV of the optical lens, and the numerical values corresponding to each conditional expression in the embodiments.

[0157] Table 5

[0158]

[0159]

[0160] 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 optical lens has one or more advantages such as large field of view, large aperture, high imaging quality, etc.

[0161] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0162] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the patent scope of the present application. It should be noted that, for ordinary skilled persons in the art, without departing from the concept of the present application, 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 consisting of eight pieces of lenses, characterized in that, In order from the object side to the imaging plane 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 concave surface, and the image side surface of which is a convex surface; a third lens with positive refractive power; a fourth lens with negative refractive power; a fifth 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; 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 positive refractive power, the object side surface of which is a concave surface, and the image side surface of which is a convex surface; an eighth lens with negative refractive power; wherein the object side surface curvature radius R3 of the second lens and the image side surface curvature radius R4 of the second lens satisfy: -0.7 < (R3-R4) / (R3+R4) < -0.3, and the object side surface curvature radius R13 of the seventh lens and the image side surface curvature radius R14 of the seventh lens satisfy: 0.4 < (R13-R14) / (R13+R14) < 1.

2. The optical lens of claim 1, wherein, The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5 < TTL / f < 10; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.5 < TTL / IH < 3.

8.

3. The optical lens of claim 1, wherein, The maximum field angle FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 50° < FOV / FNO < 85°; 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: 3.7 < IH / EPD < 5.

8.

4. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.9 < IH / f < 2.9; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1 < BFL / f < 2.

5. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.6 < f1 / f < -1.4; the effective focal length f of the optical lens and the object side surface curvature radius R1 of the first lens satisfy: 3.2 < R1 / f < 10; the effective focal length f of the optical lens and the image side surface curvature radius R2 of the first lens satisfy: 0.75 < R2 / f < 1.

6.

6. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -14 < f2 / f < -5.7; the effective focal length f of the optical lens and the object side surface curvature radius R3 of the second lens satisfy: -4.6 < R3 / f < -3.1; the effective focal length f of the optical lens and the image side surface curvature radius R4 of the second lens satisfy: -15 < R4 / f < -8.

7. The optical lens of claim 1, wherein, An effective focal length f of the optical lens and a focal length f5 of the fifth lens satisfy: 1 < f5 / f < 1.5; the effective focal length f of the optical lens and a radius of curvature R9 on an object side of the fifth lens satisfy: 1 < R9 / f < 3.2; the effective focal length f of the optical lens and a radius of curvature R10 on an image side of the fifth lens satisfy: -1.8 < R10 / f < -0.

9.

8. The optical lens of claim 1, wherein, An effective focal length f of the optical lens and a focal length f6 of the sixth lens satisfy: -6 < f6 / f < -1.5; a radius of curvature R11 on an object side of the sixth lens and a radius of curvature R12 on an image side of the sixth lens satisfy: -1 < (R11-R12) / (R11+R12) < -0.

5.

9. The optical lens of claim 1, wherein, An effective focal length f of the optical lens and a focal length f7 of the seventh lens satisfy: 2 < f7 / f < 3; a radius of curvature R13 on an object side of the seventh lens and the effective focal length f of the optical lens satisfy: -50 < R13 / f < -3.4; a radius of curvature R14 on an image side of the seventh lens and the effective focal length f of the optical lens satisfy: -1.7 < R14 / f < -1.

10. The optical lens of claim 1, wherein, A combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 1.5 < f45678 / f < 3; a half radius of light passing d1 on an object side of the first lens and a half radius of light passing d16 on an image side of the eighth lens satisfy: 1.3 < d1 / d16 < 4.

Images