Optical lens

Abstract

The application provides an optical lens, which comprises eight lenses in sequence along an optical axis from an object side to an imaging surface, and the eight lenses comprise: a first lens with negative optical power, wherein the object side surface and the image side surface of the first lens are both concave surfaces; a second lens with positive optical power, wherein the object side surface and the image side surface of the second lens are both convex surfaces; a third lens with negative optical power, wherein the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a concave surface near the optical axis; a fourth lens with positive optical power, wherein the image side surface of the fourth lens is a convex surface; a fifth lens with positive optical power, wherein the object side surface and the image side surface of the fifth lens are both convex surfaces; a sixth lens with negative optical power, wherein the object side surface and the image side surface of the sixth lens are both concave surfaces; a seventh lens with positive optical power, wherein the object side surface and the image side surface of the seventh lens are both convex surfaces; and an eighth lens with positive optical power, wherein the object side surface of the eighth lens is a concave surface, and the image side surface of the eighth lens is a convex surface. The optical lens provided by the application can improve the imaging quality of the optical lens, reduce aberration and improve the imaging quality of the optical lens.

Description

TECHNICAL FIELD

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

[0002] In the field of intelligent manufacturing, industrial lenses are widely used, with many advantages such as high precision, high speed, and high efficiency, and can record key parameters and data in the production process at any time, thereby improving production efficiency and product quality. It can be predicted that the market of industrial lenses will grow explosively in the future, and their application in intelligent manufacturing will be more extensive. With the continuous upgrading of industrial lenses, the requirements of intelligent manufacturing for industrial lenses will also be higher and higher, and good imaging effect has become the main development trend of industrial lenses.

[0003] However, the existing industrial lenses still have many shortcomings, for example, most lenses can well image the object when shooting close-up, but the imaging of distant objects is poor, and cannot balance the clear imaging of long distance; the increase of the field angle of view of the lens leads to difficulty in system aberration correction and decline of imaging quality; it is difficult to meet market demand. SUMMARY

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

[0005] To achieve the above purpose, the technical scheme adopted by the present application is:

[0006] An optical lens, a total of eight lenses, including in order along the optical axis from the object side to the imaging surface:

[0007] The first lens with negative focal power, the object side and the image side are both concave;

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

[0009] The third lens with negative focal power, the object side is concave, and the image side is concave near the optical axis;

[0010] The fourth lens with positive focal power, the image side is convex;

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

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

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

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

[0015] wherein the first lens has a curvature radius R1 on the object side and a curvature radius R2 on the image side, and the following condition is satisfied: 0.2 < (R1+R2) / (R1-R2) < 0.8.

[0016] Further preferably, the total track length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2 < TTL / f < 2.4.

[0017] Further preferably, 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 < TTL / IH < 2.4.

[0018] Further preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 4.7 < f8 / f < 12.2.

[0019] Further preferably, the effective focal length f of the optical lens and the combined focal length f567 of the fifth lens, the sixth lens and the seventh lens satisfy: 1.2 < f567 / f < 1.9.

[0020] Further preferably, the effective focal length f of the optical lens and the curvature radius R1 on the object side of the first lens satisfy: -2.65 < R1 / f < -0.7; the effective focal length f of the optical lens and the curvature radius R2 on the image side of the first lens satisfy: 0.35 < R2 / f < 0.65.

[0021] Further preferably, the effective focal length f of the optical lens and the curvature radius R15 on the object side of the eighth lens satisfy: -0.45 < R15 / f < -0.3.

[0022] Further preferably, the curvature radius R15 on the object side of the eighth lens and the curvature radius R16 on the image side of the eighth lens satisfy: 0.7 < R15 / R16 < 1.

[0023] Further preferably, the curvature radius R15 on the object side of the eighth lens and the curvature radius R16 on the image side of the eighth lens satisfy: -0.2 < (R15-R16) / (R15+R16) < 0.

[0024] Further preferably, the sagittal height Sag1 of the half light entrance radius on the object side of the first lens and the half light entrance radius d1 on the object side of the first lens satisfy: -0.2 < Sag1 / d1 < 0; the sagittal height Sag2 of the half light entrance radius on the image side of the first lens and the half light entrance radius d2 on the image side of the first lens satisfy: 0.1 < Sag2 / d2 < 0.35.

[0025] The optical lens provided by the application adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens is improved, the aberration is reduced, and the imaging quality of the optical lens is improved, so that the lens has one or more advantages such as long focus, large image surface and high imaging quality. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the following drawings, in which:

[0027] Figure 1 It is a structural schematic diagram of the optical lens in embodiment 1 of the application.

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

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

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

[0031] Figure 5 It is a curve of the optical lens in embodiment 1 of the application. Axial chromatic aberration.

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

[0033] Figure 7 It is a relative luminance curve of the optical lens in embodiment 1 of the application.

[0034] Figure 8 It is a structural schematic diagram of the optical lens in embodiment 2 of the application.

[0035] Figure 9 It is a field curvature curve of the optical lens in embodiment 2 of the application.

[0036] Figure 10 It is an F-Tan(Theta) distortion curve of the optical lens in embodiment 2 of the application.

[0037] Figure 11 It is an axial aberration curve of the optical lens in embodiment 2 of the application.

[0038] Figure 12 It is a curve of the optical lens in embodiment 2 of the application. Axial chromatic aberration.

[0039] Figure 13 It is an MTF curve of the optical lens in embodiment 2 of the application.

[0040] Figure 14 A relative illumination curve graph for the optical lens of Embodiment 2 of the present application.

[0041] Figure 15 A structure diagram for the optical lens of Embodiment 3 of the present application.

[0042] Figure 16 A field curvature curve graph for the optical lens of Embodiment 3 of the present application.

[0043] Figure 17 An F-Tan(Theta) distortion curve for the optical lens of Embodiment 3 of the present application.

[0044] Figure 18 An axial aberration curve graph for the optical lens of Embodiment 3 of the present application.

[0045] Figure 19 A sagittal color aberration curve graph for the optical lens of Embodiment 3 of the present application.

[0046] Figure 20 An MTF curve graph for the optical lens of Embodiment 3 of the present application.

[0047] Figure 21 A relative illumination curve graph for the optical lens of Embodiment 3 of the present application.

[0048] The following detailed description will further describe the present application with reference to the above drawings. DETAILED DESCRIPTION

[0049] For a better understanding of the present application, various aspects of the present application will be described in relation to the drawings. It is to be understood 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.

[0050] 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.

[0051] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for the sake of convenience in explanation. Specifically, the shape of the spherical surface or the aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0052] In the present disclosure, 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.

[0053] It should also be understood that the use of the terms "including", "including", "having", "containing", and / or "containing", when used in this specification, means that the presence of the stated features, elements and / or components, but does not exclude 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 and not the individual elements in the list. In addition, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application". And the term "exemplary" is intended to refer to an example or illustration.

[0054] 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 the present application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0055] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0056] The optical lens of the embodiment of the present application has eight lenses, which are, in order from the object side to the image plane along the optical axis: 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.

[0057] In some embodiments, the first lens can have a negative focal power, and both its object side surface and its image side surface are concave. The second lens can have a positive focal power, and both its object side surface and its image side surface are convex. The third lens can have a negative focal power, and its object side surface is concave, and its image side surface is concave at the paraxial region. The fourth lens can have a positive focal power, and its object side surface can be concave or convex, and its image side surface is convex. The fifth lens can have a positive focal power, and both its object side surface and its image side surface are convex. The sixth lens can have a negative focal power, and both its object side surface and its image side surface are concave. The seventh lens can have a positive focal power, and both its object side surface and its image side surface are convex. The eighth lens can have a positive focal power, and its object side surface is concave, and its image side surface is convex.

[0058] In some embodiments, the optical lens can further include a diaphragm, which can be located between the object side and the first lens. It can be understood that the diaphragm is used to limit the amount of light to change the brightness of the imaging.

[0059] 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 to prevent interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0060] In some embodiments, the first lens and the second lens can be glued to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the sensitivity of the optical lens to decentration, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0061] In some embodiments, the fifth lens, the sixth lens, and the seventh lens can be glued to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the sensitivity of the optical lens to decentration, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0062] In some embodiments, the object side surface curvature radius R1 of the first lens and the image side surface curvature radius R2 of the first lens satisfy: 0.2<(R1+R2) / (R1-R2)<0.8. Satisfying the above range is conducive to relaxing the degree of deflection of light passing through the first lens, effectively reducing the working aperture of the first lens, and reducing the difficulty of subsequent lens aberration correction. More specifically, 0.28<(R1+R2) / (R1-R2)<0.67.

[0063] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2<TTL / f<2.4. Satisfying the above range is conducive to limiting the total length of the lens while better achieving the long-focus performance of the system. More specifically, 2.29<TTL / f<2.4.

[0064] In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 2<TTL / IH<2.4. Satisfying the above range is conducive to achieving a balance between the volume and the large image surface of the optical lens. More specifically, 2.21<TTL / IH<2.34.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 4.7 < f8 / f < 12.2. Satisfying the above range, the eighth lens can have positive refractive power, control the smoothness of the light path, and pass more light to the imaging surface, thereby improving the imaging quality of the optical lens. More specifically, 5.18 < f8 / f < 11.08.

[0066] In some embodiments, the effective focal length f of the optical lens and the combined focal length f567 of the fifth lens, the sixth lens and the seventh lens satisfy: 1.2 < f567 / f < 1.9. Satisfying the above range, the fifth lens, the sixth lens and the seventh lens form a cemented lens group with positive refractive power, and by reasonably setting the focal length of the cemented lens group, the chromatic aberration of the optical lens can be effectively corrected, the sensitivity of the optical lens to decentration can be reduced, the aberration of the optical lens can be balanced, and the imaging quality of the optical lens can be improved. More specifically, 1.32 < f567 / f < 1.76.

[0067] In some embodiments, the effective focal length f of the optical lens and the object side surface curvature radius R1 of the first lens satisfy: -2.65 < R1 / f < -0.7; and the effective focal length f of the optical lens and the image side surface curvature radius R2 of the first lens satisfy: 0.35 < R2 / f < 0.65. Satisfying the above range, by reasonably setting the surface type of the first lens, the light entering the system can be effectively increased, and the imaging quality in bright and dark environments can be improved. More specifically, -2.41 < R1 / f < -0.78; and 0.43 < R2 / f < 0.57.

[0068] In some embodiments, the effective focal length f of the optical lens and the object side surface curvature radius R15 of the eighth lens satisfy: -0.45 < R15 / f < -0.3. Satisfying the above range, the surface type of the object side surface of the eighth lens is controlled, which is beneficial to increasing the imaging area and the field of view. More specifically, -0.4 < R15 / f < -0.36.

[0069] In some embodiments, the object side surface curvature radius R15 of the eighth lens and the image side surface curvature radius R16 of the eighth lens satisfy: 0.7 < R15 / R16 < 1. Satisfying the above range, the surface type of the eighth lens is controlled, which can effectively correct the aberration and improve the imaging quality of the optical lens. More specifically, 0.77 < R15 / R16 < 0.86.

[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: -0.2 < (R15-R16) / (R15+R16) < 0. Satisfying the above range, the object side surface and the image side surface of the eighth lens are controlled to have reasonable shapes, and the imaging quality is improved. More specifically, -0.13 < (R15-R16) / (R15+R16) < -0.07.

[0071] In some embodiments, the sagittal height Sag1 of the object side surface of the first lens and the half diameter d1 of the object side surface of the first lens satisfy: -0.2 < Sag1 / d1 < 0; the sagittal height Sag2 of the image side surface of the first lens and the half diameter d2 of the image side surface of the first lens satisfy: 0.1 < Sag2 / d2 < 0.35. Satisfying the above range, the trend of the edge field of view light is controlled, and the detail information of the central field of view of the optical lens is highlighted. More specifically, -0.12 < Sag1 / d1 < -0.03; 0.18 < Sag2 / d2 < 0.27.

[0072] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV, and the real image height IH corresponding to the maximum field of view satisfy: 0.85 < (IH / 2) / (f*tan(FOV / 2)) < 0.95. Satisfying the above range, the size of distortion can be controlled, and the imaging quality of the optical lens is improved. More specifically, 0.87 < (IH / 2) / (f*tan(FOV / 2)) < 0.91.

[0073] In some embodiments, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view satisfy: 1 < IH / f < 1.1. Satisfying the above range, the long focal characteristics of the lens can be realized, thereby meeting the local shooting requirements, and the large image surface characteristics of the lens can be realized, realizing high-definition imaging of the lens. More specifically, 1 < IH / f < 1.05.

[0074] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.4 < f1 / f < -0.5. Satisfying the above range, the first lens can have a negative refractive power, which is beneficial to reduce the inclination angle of the incident light, and is beneficial to collect as much edge field of view light as possible into the rear optical lens, realizing large-angle light collection. More specifically, -1.28 < f1 / f < -0.6.

[0075] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.4 < f2 / f < 0.7. Satisfying the above range, the second lens is defined to have appropriate positive refractive power, which is beneficial to the convergence of light rays, makes the divergent light rays entering the system from the front smoothly enter the rear optical system, the light ray trend is more gentle, the aberration is optimized, and the resolution is improved. More specifically, 0.44 < f2 / f < 0.67.

[0076] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -0.9 < f3 / f < -0.5. Satisfying the above range, it is beneficial to slow down the deflection degree of the incident light, avoid too strong refraction change to generate too much aberration, and at the same time, it is beneficial to balance various aberrations generated by the front lens group, and improve the overall imaging quality. More specifically, -0.75 < f3 / f < -0.53.

[0077] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.6 < f4 / f < 1.1. Satisfying the above range, the light rays can be effectively converged, the aberration generated by the front lens is corrected, and the overall imaging quality is improved. More specifically, 0.7 < f4 / f < 1.01.

[0078] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.6 < f5 / f < 1.4. Satisfying the above range, the fifth lens can have positive refractive power, which is beneficial to improve the light convergence ability of the optical lens, and at the same time, it can balance the aberration of the optical lens, and improve the imaging quality of the optical lens. More specifically, 0.69 < f5 / f < 1.28.

[0079] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.3 < f6 / f < -0.5. Satisfying the above range, the sixth lens can have negative refractive power, which is beneficial to increase the imaging area and the field of view of the optical lens, and improve the imaging quality of the optical lens. More specifically, -1.14 < f6 / f < -0.54.

[0080] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1 < f7 / f < 1.4. Satisfying the above range, the seventh lens can have positive refractive power, which is beneficial to improve the light convergence ability of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens. More specifically, 1.14 < f7 / f < 1.2.

[0081] In some embodiments, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 1.1 < f12 / f < 1.6. Satisfying the above range, the first lens and the second lens form a cemented lens group with positive refractive power, and by reasonably setting the focal length of the cemented lens group, the chromatic aberration of the optical lens can be effectively corrected, the decentration sensitivity of the optical lens can be reduced, the aberration of the optical lens can be balanced, and the imaging quality of the optical lens can be improved. More specifically, 1.24 < f12 / f < 1.48.

[0082] In some embodiments, the effective focal length f of the optical lens and the object side surface radius of curvature R3 of the second lens satisfy: 0.35 < R3 / f < 0.65. Satisfying the above range, by reasonably setting the shape of the object side surface of the second lens, the light rays can be converged, the aberration caused by the first lens can be balanced, the difficulty of distortion correction can be reduced, the image at the edge field of view of the lens can not be distorted, and the imaging quality of the optical system can be improved. More specifically, 0.43 < R3 / f < 0.57.

[0083] In some embodiments, the effective focal length f of the optical lens and the object side surface radius of curvature R9 of the fifth lens satisfy: 1.2 < R9 / f < 2. Satisfying the above range, the shape of the object side surface of the fifth lens is limited, which helps to reasonably control the light ray trend, reduce the aberration, and improve the imaging quality of the optical lens. More specifically, 1.37 < R9 / f < 1.8.

[0084] In some embodiments, the effective focal length f of the optical lens and the object side surface radius of curvature R13 of the seventh lens satisfy: 1.1 < R13 / f < 1.5. Satisfying the above range, the shape of the object side surface of the seventh lens is limited, which helps to reasonably control the light ray trend, reduce the aberration, and improve the imaging quality of the optical lens. More specifically, 1.25 < R13 / f < 1.36.

[0085] In some embodiments, the effective focal length f of the optical lens and the image side surface radius of curvature R16 of the eighth lens satisfy: -0.55 < R16 / f < -0.4. Satisfying the above range, it is beneficial to converge light rays and transmit more light rays to the imaging surface, thereby improving the imaging quality of the optical lens. More specifically, -0.49 < R16 / f < -0.43.

[0086] In some embodiments, the object side surface radius of curvature R3 of the second lens and the image side surface radius of curvature R4 of the second lens satisfy: -0.75 < (R3+R4) / (R3-R4) < -0.3. Satisfying the above range, the light ray trend is stable, and the aberration correction pressure of the rear end lens of the optical lens is reduced. More specifically, -0.68 < (R3+R4) / (R3-R4) < -0.39.

[0087] In some embodiments, the object-side surface curvature radius R9 of the fifth lens and the image-side surface curvature radius R10 of the fifth lens satisfy: 0.25 < (R9+R10) / (R9-R10) < 0.6. Satisfying the above range can reduce spherical aberration while improving relative illumination at the edge field of view. More specifically, 0.31 < (R9+R10) / (R9-R10) < 0.46.

[0088] In some embodiments, the object-side surface curvature radius R13 of the seventh lens and the image-side surface curvature radius R14 of the seventh lens satisfy: -0.85 < (R13-R14) / (R13+R14) < -0.1. Satisfying the above range can control the seventh lens to have a proper surface shape, effectively improve field curvature and aberration, and improve imaging quality. More specifically, -0.68 < (R13-R14) / (R13+R14) < -0.15.

[0089] In some embodiments, the total length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis respectively satisfy: 0.6 < ∑CT / TTL < 0.85. Satisfying the above range can effectively compress the total length of the optical lens, while being conducive to the structural design and production process of the optical lens. More specifically, 0.69 < ∑CT / TTL < 0.75.

[0090] In some embodiments, the object-side surface half-aperture radius d1 of the first lens and the image-side surface half-aperture radius d16 of the eighth lens satisfy: 0.25 < d1 / d16 < 0.35. Satisfying the above range can control the aperture ratio of the front and rear lenses to be within a reasonable range, and make the imaging plane illumination uniform. More specifically, 0.29 < d1 / d16 < 0.32.

[0091] In some embodiments, the object-side surface half-aperture radius d1 of the first lens, the real image height IH corresponding to the maximum field angle of view of the optical lens, and the maximum field angle of view FOV of the optical lens satisfy: 0.5 < d1 / (IH / 2) / tan(FOV / 2) < 0.65. Satisfying the above range can balance the relationship among the front-end aperture, field angle of view, and image size of the optical lens, and be conducive to miniaturization. More specifically, 0.55 < d1 / (IH / 2) / tan(FOV / 2) < 0.58.

[0092] In some embodiments, the optical lens satisfies the condition formula: 12.2mm < f < 15.2mm, 55° < FOV < 65°, 3.6mm < EPD < 4.4mm, 30mm < TTL < 34mm, 3 < Fno < 3.7, 12.6mm < IH < 15.5mm, 1.7° < CRA < 3.6°, 4mm < BFL < 4.5mm, wherein f represents an effective focal length of the optical lens, FOV represents a maximum field of view angle of the optical lens, EPD represents an entrance pupil diameter of the optical lens, TTL represents an optical total length of the optical lens, Fno represents an aperture value of the optical lens, IH represents an image height corresponding to the maximum field of view angle of the optical lens, CRA represents a chief ray angle of incidence at the maximum image height of the optical lens, and BFL represents a back focal length of the optical lens. Satisfying the above condition indicates that the optical lens provided by the embodiments of the present application at least has the characteristics of long focal length, large image surface, and small CRA. More specifically, 13.4mm < f < 13.9mm, 59.9° < FOV < 60.1°, 3.9mm < EPD < 4.1mm, 31.1mm < TTL < 32.9mm, 3.3 < Fno < 3.4, 14mm < IH < 14.1mm, 1.8° < CRA < 3.4°, 4.1mm < BFL < 4.3mm.

[0093] In some embodiments, the lens material in the optical lens provided by the present application can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. When the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The optical lens provided by the present application can adopt a full-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0094] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt a spherical lens or an aspherical lens. Compared with a spherical structure, an aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving lens miniaturization. More specifically, the first lens, the second lens, the fifth lens, the sixth lens, and the seventh lens of the present application adopt a spherical lens, and the third lens, the fourth lens, and the eighth lens adopt an aspherical lens.

[0095] In various embodiments of the present application, when the lens adopts an aspherical lens, each aspherical surface shape of the optical lens satisfies the following equation:

[0096]

[0097] Wherein, z is the distance of the curved surface and the curved surface vertex in the direction of the optical axis, h is the distance of the optical axis to the curved surface, c is the curvature of the curved surface vertex, K is the quadratic curved surface coefficient, B, C, D, E, F, G, H are the fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, sixteenth order curved surface coefficients respectively.

[0098] The application will be further described in the following embodiments. In each embodiment, the thickness, the radius of curvature, 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 the preferred embodiments of the application, but the embodiments of the application are not limited to the following embodiments only, any changes, substitutions, combinations or simplifications made without departing from the innovative points of the application should be regarded as equivalent replacement, and are included in the protection scope of the application.

[0099] Embodiment 1

[0100] Please refer to Figure 1 , which is a structural schematic diagram of the optical lens 100 provided in the embodiment 1 of the application. The optical lens includes, along the optical axis from the object side to the imaging surface, a diaphragm ST, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G1.

[0101] The first lens L1 has negative focal power, and the object side S1 and the image side S2 are both concave surfaces;

[0102] The second lens L2 has positive focal power, and the object side S2 and the image side S3 are both convex surfaces;

[0103] The first lens L1 and the second lens L2 form a cemented lens group with positive focal power, that is, the cemented surface of the image side of the first lens L1 and the object side of the second lens L2 is S2;

[0104] The third lens L3 has negative focal power, and the object side S4 is a concave surface, and the image side S5 is a concave surface near the optical axis;

[0105] The fourth lens L4 has positive focal power, and the object side S6 and the image side S7 are both convex surfaces;

[0106] The fifth lens L5 has positive focal power, and the object side S8 and the image side S9 are both convex surfaces;

[0107] The sixth lens L6 has negative focal power, and the object side S9 and the image side S10 are both concave surfaces;

[0108] The seventh lens L7 has positive focal power, and the object side S10 and the image side S11 are both convex surfaces;

[0109] The fifth lens L5, the sixth lens L6 and the seventh lens L7 form a cemented lens group with positive refractive power, wherein the cemented surface of the image side surface of the fifth lens L5 and the object side surface of the sixth lens L6 is S9; the cemented surface of the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7 is S10;

[0110] The eighth lens L8 has positive refractive power, the object side surface S12 is a concave surface, and the image side surface S13 is a convex surface;

[0111] The object side surface S14 and the image side surface S15 of the filter G1 are both flat surfaces;

[0112] The imaging surface S16 is a flat surface.

[0113] The first lens, the second lens, the fifth lens, the sixth lens and the seventh lens are glass spherical lenses, and the third lens, the fourth lens and the eighth lens are glass aspherical lenses.

[0114] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0115] Table 1-1

[0116]

[0117]

[0118] The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0119] Table 1-2

[0120] Surface number K B C D E F G H S4 1.33E+00 -5.69E-05 8.20E-05 -7.97E-06 1.74E-06 -1.47E-07 7.22E-09 -8.89E-11 S5 -7.12E+01 -1.36E-03 6.75E-05 -1.66E-06 3.31E-09 4.52E-10 4.56E-11 -2.49E-12 S6 3.61E+01 -1.39E-03 6.24E-05 -6.59E-07 1.24E-09 -8.69E-11 -9.88E-12 2.72E-13 S7 -5.44E-01 2.09E-04 -3.72E-06 5.87E-07 -1.84E-08 4.89E-10 1.09E-11 -1.63E-13 S12 -5.37E+00 9.00E-04 -2.55E-05 5.33E-07 -5.91E-09 2.31E-11 1.75E-13 -1.51E-15 S13 -4.84E+00 1.07E-03 -3.33E-05 6.05E-07 -4.64E-09 -7.16E-12 3.57E-13 -1.04E-15

[0121] In this embodiment, the field curvature curve, the F-Tan(Theta) distortion curve, the axial aberration curve, the transverse chromatic aberration curve, the MTF curve and the relative luminance curve of the optical lens 100 are shown in FIGS. 1-1 to 1-5 respectively. Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7

[0122] Figure 2 The field curvature curve of Embodiment 1 is shown, which represents the bending degree of light rays of different wavelengths on the meridional image surface and the sagittal image surface, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.06 mm, which shows that the optical lens can well correct the field curvature.

[0123] Figure 3 ​The F-Tan (Theta) distortion curve of the optical lens of the embodiment 1 is shown, which represents the distortion of light rays of different wavelengths at different image heights on the imaging plane, the horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field of view (unit: °). It can be seen from the figure that the distortion of the optical lens is controlled within ±10%, which shows that the optical lens can well correct the distortion.

[0124] Figure 4 The axial aberration curve of the optical lens 100 in the embodiment is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the offset of the axial aberration is controlled within ±0.03mm, which shows that the optical lens 100 can well correct the axial aberration.

[0125] Figure 5 The curve of the optical lens 100 in the embodiment is shown, which represents the aberration of each wavelength on the imaging plane at different image heights with respect to the central wavelength (0.55μm), the horizontal axis represents the vertical chromatic aberration value of each wavelength with respect to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±3.5μm, which shows that the optical lens 100 can well correct the chromatic aberration.

[0126] Figure 6 The MTF (Modulation Transfer Function) curve of the embodiment 1 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. It can be seen from the figure that the MTF value of the embodiment is above 0.3 in the full field of view, and in the range of 0-200lp / mm, the MTF curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in the case of low frequency and high frequency.

[0127] Figure 7 The relative illumination curve of the embodiment 1 is shown, which represents the relative illumination value of different field angles on the imaging plane, the horizontal axis represents the half field of view (unit: °), and the vertical axis represents the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 80% at the maximum half field of view, which shows that the optical lens has good relative illumination.

[0128] Embodiment 2

[0129] Please refer to Figure 8The figure shows a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The optical lens in this embodiment is roughly the same as that in Embodiment 1. The main difference is that the object side surface S6 of the fourth lens L4 is concave; the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0130] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0131] Table 2-1

[0132]

[0133]

[0134] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0135] Table 2-2

[0136] Surface number K B C D E F G H S4 5.18E+00 -4.72E-03 1.65E-04 -1.69E-05 1.73E-06 -1.37E-07 7.13E-09 -9.86E-11 S5 -2.00E+02 -2.59E-03 8.00E-05 -1.26E-06 1.71E-09 5.43E-11 4.01E-11 -1.15E-12 S6 -3.09E+01 -8.55E-04 5.42E-05 -8.64E-07 2.86E-09 2.69E-10 -1.09E-11 1.19E-13 S7 -5.95E-01 4.23E-04 -1.50E-05 9.68E-07 -2.14E-08 2.74E-10 5.41E-12 -1.09E-13 S12 -6.33E+01 1.02E-03 -3.26E-05 5.63E-07 -5.46E-09 2.28E-11 1.28E-13 -1.32E-15 S13 -2.00E+02 1.86E-03 -6.39E-05 9.85E-07 -5.31E-09 -3.27E-11 3.51E-13 2.27E-15

[0137] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination curve of the optical lens 200 are respectively as follows: Figure 9 , Figure 10 , Figure 11 , Figure 12 , Figure 13 , Figure 14 As shown.

[0138] from Figure 9 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.06mm, indicating that the optical lens can effectively correct field curvature.

[0139] from Figure 10 As can be seen, the distortion of the optical lens is controlled within ±10%, indicating that the optical lens can effectively correct distortion.

[0140] from Figure 11 As can be seen, the axial aberration offset is controlled within ±0.03mm, indicating that the optical lens can effectively correct axial aberration.

[0141] from Figure 12 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±5μm, indicating that the optical lens can correct chromatic aberration well.

[0142] from Figure 13It can be seen from the MTF curves in the full field of view that the MTF values of the optical lens are all above 0.3, and the MTF curves are uniformly and smoothly decreased from the center to the edge of the field of view in the range of 0-200 lp / mm, and the optical lens has good imaging quality and good detail resolution capability in the case of low frequency and high frequency.

[0143] From Figure 14 It can be seen from the relative illumination curves in the maximum half field of view that the relative illumination values of the optical lens are still greater than 80%, which indicates that the optical lens has good relative illumination.

[0144] Embodiment 3

[0145] Please refer to Figure 15 , which is a structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present application. The optical lens in this embodiment is substantially the same as that in Embodiment 1, and the main difference is that the optical parameters such as the curvature radius, aspheric coefficient and thickness of each lens surface profile are different.

[0146] The related parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0147] Table 3-1

[0148]

[0149] The surface profile parameters of the aspheric lens of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0150] Table 3-2

[0151]

[0152]

[0153] In this embodiment, the field curvature curve, F-Tan(Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve and relative illumination curve of the optical lens 300 are shown in Figure 16 、 Figure 17 、 Figure 18 、 Figure 19 、 Figure 20 、 Figure 21 respectively.

[0154] From Figure 16 It can be seen that the field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.06 mm, which indicates that the optical lens can well correct the field curvature.

[0155] From Figure 17 It can be seen that the distortion of the optical lens is controlled within ±10%, which indicates that the optical lens can well correct the distortion.

[0156] From the above Table 2, it can be seen that the axial aberration is controlled within ±0.03 mm, which indicates that the optical lens can correct the axial aberration well. Figure 18

[0157] From the above Table 3, it can be seen that the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±3 μm, which indicates that the optical lens can correct the chromatic aberration well. Figure 19

[0158] From the above Table 4, it can be seen that the MTF value of the embodiment is above 0.45 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 in the range of 0-200 lp / mm, which indicates that the optical lens has good imaging quality and good detail resolution ability in the low frequency and high frequency cases. Figure 20

[0159] From the above Table 5, it can be seen that the relative luminance value of the optical lens is still greater than 80% at the maximum half field of view, which indicates that the optical lens has good relative luminance. Figure 21

[0160] Please refer to Table 4, which is the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total optical length TTL, the aperture value Fno, the real image height IH corresponding to the maximum field of view, the chief ray angle of incidence CRA at the maximum image height, the maximum field of view FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0161] Table 4

[0162]

[0163]

[0164] In summary of the above embodiments, the optical lens provided by the present application adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved, so that the lens has one or more advantages such as long focal length, large image surface, and high imaging quality.

[0165] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0166] ​​​​The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An optical lens, eight pieces of lenses in total, characterized in that, In order from the object side to the imaging plane along the optical axis, the optical lens comprises successively: a first lens with negative refractive power, both the object side surface and the image side surface of which are concave; a second lens with positive refractive power, both the object side surface and the image side surface of which are convex; a third lens with negative refractive power, the object side surface of which is concave, and the image side surface of which is concave at the near optical axis; a fourth lens with positive refractive power, the image side surface of which is convex; a fifth lens with positive refractive power, both the object side surface and the image side surface of which are convex; a sixth lens with negative refractive power, both the object side surface and the image side surface of which are concave; a seventh lens with positive refractive power, both the object side surface and the image side surface of which are convex; an eighth lens with positive refractive power, the object side surface of which is concave, and the image side surface of which is convex; wherein the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R2 of the image side surface of the first lens satisfy: 0.2<(R1+R2) / (R1-R2)<0.8; 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<TTL / IH<2.4; the sagittal height Sag1 of the object side surface of the first lens and the half-diameter d1 of the object side surface of the first lens satisfy: -0.2<Sag1 / d1<0; the sagittal height Sag2 of the image side surface of the first lens and the half-diameter d2 of the image side surface of the first lens satisfy: 0.1<Sag2 / d2<0.

35.

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: 2<TTL / f<2.

4.

3. The optical lens of claim 1, wherein, the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R2 of the image side surface of the first lens satisfy: 0.28<(R1+R2) / (R1-R2)<0.67; 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: 2.21<TTL / IH<2.

34.

4. The optical lens of claim 1, wherein, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 4.7<f8 / f<12.

2.

5. The optical lens of claim 1, wherein, the effective focal length f of the optical lens and the combined focal length f567 of the fifth lens, the sixth lens and the seventh lens satisfy: 1.2<f567 / f<1.

9.

6. The optical lens of claim 1, wherein, 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: -2.65<R1 / f<-0.7; 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: 0.35<R2 / f<0.

65.

7. The optical lens of claim 1, wherein, the effective focal length f of the optical lens and the radius of curvature R15 of the object side surface of the eighth lens satisfy: -0.45<R15 / f<-0.

3.

8. The optical lens of claim 1, wherein, 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: 0.7<R15 / R16<1.

9. The optical lens of claim 1, wherein, 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: -0.2<(R15-R16) / (R15+R16)<0.

10. The optical lens of claim 1, wherein, The sagittal height of the object-side half light aperture radius Sag1 of the first lens satisfies -0.12<Sag1 / d1<-0.03; the sagittal height of the image-side half light aperture radius Sag2 of the first lens satisfies 0.18<Sag2 / d2<0.27.

Images