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 an image side of the first lens is a concave surface; a second lens with positive optical power, wherein an image side of the second lens is a convex surface; a third lens with negative optical power, wherein an object side of the third lens is a convex surface, and an image side of the third lens is a concave surface; a fourth lens with positive optical power, wherein both an object side and an image side of the fourth lens are convex surfaces; a fifth lens with positive optical power, wherein both an object side and an image side of the fifth lens are convex surfaces; a sixth lens with negative optical power, wherein both an object side and an image side of the sixth lens are concave surfaces; a seventh lens with negative optical power, wherein an object side of the seventh lens is a concave surface, and an image side of the seventh lens is a convex surface; and an eighth lens with positive optical power, wherein both an object side and an image side of the eighth lens are convex surfaces. The optical lens provided by the application improves the imaging quality of the optical lens, reduces aberration and improves the imaging quality of the optical lens through reasonable configuration of the surface types of the lenses and reasonable matching of the optical powers.

Description

TECHNICAL FIELD

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

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

[0003] Advanced Driver Assistance System (ADAS) plays an important role in intelligent driving, which collects environmental information through various lenses combined with sensors to ensure the safety of drivers. In addition to the requirements of light, thin, small shape and high pixel, high resolution of the existing ADAS system lenses, the optical lens is required to clearly image under low illumination conditions, so it is necessary to develop an optical lens with good imaging effect. SUMMARY

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

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

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

[0007] The first lens with negative focal power, the image side is concave;

[0008] The second lens with positive focal power, the image side is convex;

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

[0010] The fourth lens with positive focal power, the object side and the image side are both 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 negative focal power, the object side is concave, and the image side is convex;

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

[0015] The object-side surface curvature radius R7 of the fourth lens and the image-side surface curvature radius R8 of the fourth lens satisfy: -10.0 < (R7-R8) / (R7+R8) < -2.0.

[0016] Further preferably, the total track length TTL of the optical lens and the effective focal length f satisfy: TTL / f < 5.5.

[0017] Further preferably, the effective focal length f of the optical lens, the maximum field of view angle FOV, and the real image height IH corresponding to the maximum field of view angle satisfy: 0.6 < (IH / 2) / (f*tan(FOV / 2)) < 0.9.

[0018] Further preferably, the maximum field of view angle FOV of the optical lens and the aperture value FNO satisfy: 35° < FOV / FNO < 70°.

[0019] Further preferably, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view angle satisfy: 1.4 < IH / f < 1.8.

[0020] Further preferably, the effective focal length f of the optical lens and the optical back focal length BFL satisfy: 0.4 < BFL / f < 0.7.

[0021] Further preferably, the maximum field of view angle FOV of the optical lens and the effective focal length f satisfy: 10.0 < FOV / f < 15.0.

[0022] Further preferably, the object-side surface curvature radius R1 of the first lens and the image-side surface curvature radius R2 of the first lens satisfy: 0.5 < (R1-R2) / (R1+R2) < 1.5.

[0023] Further preferably, the object-side surface curvature radius R5 of the third lens and the image-side surface curvature radius R6 of the third lens satisfy: 0.01 < (R5-R6) / (R5+R6) < 0.25.

[0024] Further preferably, the total track length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis satisfy: 0.4 < ∑CT / TTL < 0.6.

[0025] The optical lens provided by the present application improves the imaging quality of the optical lens, reduces aberration, and improves the imaging quality of the optical lens by reasonable configuration of each lens surface and reasonable matching of optical power. 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 The structure diagram of the optical lens in the embodiment 1 of the present application.

[0028] Figure 2 The field curvature curve of the optical lens in the embodiment 1 of the present application.

[0029] Figure 3 The F-Tanθ distortion curve of the optical lens in the embodiment 1 of the present application.

[0030] Figure 4 The relative illumination curve of the optical lens in the embodiment 1 of the present application.

[0031] Figure 5 The MTF curve of the optical lens in the embodiment 1 of the present application.

[0032] Figure 6 The axial aberration curve of the optical lens in the embodiment 1 of the present application.

[0033] Figure 7 The lateral chromatic aberration curve of the optical lens in the embodiment 1 of the present application.

[0034] Figure 8 The structure diagram of the optical lens in the embodiment 2 of the present application.

[0035] Figure 9 The field curvature curve of the optical lens in the embodiment 2 of the present application.

[0036] Figure 10 The F-Tanθ distortion curve of the optical lens in the embodiment 2 of the present application.

[0037] Figure 11 The relative illumination curve of the optical lens in the embodiment 2 of the present application.

[0038] Figure 12 The MTF curve of the optical lens in the embodiment 2 of the present application.

[0039] Figure 13 The axial aberration curve of the optical lens in the embodiment 2 of the present application.

[0040] Figure 14 The lateral chromatic aberration curve of the optical lens in the embodiment 2 of the present application.

[0041] Figure 15 The structure diagram of the optical lens in the embodiment 3 of the present application.

[0042] Figure 16 The field curvature curve of the optical lens in the embodiment 3 of the present application.

[0043] Figure 17F-Tan Theta Distortion Curve of the optical lens in Embodiment 3 of the present application.

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

[0045] Figure 19 MTF Curve of the optical lens in Embodiment 3 of the present application.

[0046] Figure 20 Axial Chromatic Aberration Curve of the optical lens in Embodiment 3 of the present application.

[0047] Figure 21 Vignetting Curve of the optical lens in 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 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.

[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 explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0052] 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.

[0053] It should also be understood that the use of the terms "including", "including", "having", "containing", and / or "comprising" when used in this specification, specifies the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. In addition, when expressions such as "at least one of" appear after a list of items, it modifies the entire list of items and not the individual items themselves. In addition, when describing embodiments of the present application, "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 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.

[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 embodiments of the present application comprises, in order from the object side to the imaging surface along the optical axis: a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a filter and a protective glass.

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

[0058] In some embodiments, the object side surface curvature radius R7 of the fourth lens and the image side surface curvature radius R8 of the fourth lens satisfy: -10.0 < (R7-R8) / (R7+R8) < -2.0. Satisfying the above range is conducive to correcting the on-axis aberration of the optical lens, improving the imaging quality of the optical lens, and also capable of improving the ghost ray angle between the third lens and the fourth lens, reducing the ghost energy.

[0059] In some embodiments, the optical total length TTL of the optical lens and the effective focal length f satisfy: TTL / f<5.5. Satisfying the above range can effectively limit the length of the lens.

[0060] In some embodiments, the effective focal length f of the optical lens, the maximum field of view angle FOV, and the real image height IH corresponding to the maximum field of view angle satisfy: 0.6<(IH / 2) / (fxtan(FOV / 2))<0.9. Satisfying the above requirement indicates that the optical distortion of the optical lens is better controlled, and the resolving power of the optical lens is improved.

[0061] In some embodiments, the maximum field of view angle FOV of the optical lens and the aperture value FNO satisfy: 35°<FOV / FNO<70°. Satisfying the above requirement is conducive to expanding the field of view angle of the optical lens and increasing the aperture of the optical lens, is conducive to the optical lens to obtain more scene information, satisfies the demand of large range detection, is conducive to improving the problem that the relative brightness of the edge field of view decreases rapidly, and thus is also conducive to obtaining more scene information.

[0062] 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 angle satisfy: 1.4<IH / f<1.8. Satisfying the above range can realize wide-angle characteristics, thereby satisfying the demand of large range shooting, and can realize large image surface characteristics, thereby improving the imaging quality of the optical lens.

[0063] In some embodiments, the effective focal length f of the optical lens and the optical back focal length BFL satisfy: 0.4<BFL / f<0.7. Satisfying the above range can reduce the interference of aberrations such as coma and coma, improve the resolution and clarity of imaging, and improve the stability of the optical lens.

[0064] In some embodiments, the maximum field of view angle FOV of the optical lens and the effective focal length f satisfy: 10.0<FOV / f<15.0. Satisfying the above range makes the optical lens capable of shooting a farther target.

[0065] 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: 0.5<(R1-R2) / (R1+R2)<1.5. Satisfying the above range can control the direction of light, reduce spherical aberration, correct coma, increase light utilization, and improve stability.

[0066] In some embodiments, the object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: 0.01<(R5-R6) / (R5+R6)<0.25. Satisfying the above range can converge the edge field of view light, is helpful for optimizing the imaging performance in low light conditions, and provides better image brightness and contrast.

[0067] In some embodiments, the total track 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: 0.4 < ∑CT / TTL < 0.6. By satisfying the above range, the total length of the optical system can be compressed, so that the structure of the system is more compact.

[0068] In some embodiments, the maximum field of view FOV of the optical lens, the real image height IH corresponding to the maximum field of view, and the entrance pupil diameter D1 of the first lens satisfy: 0.5 < D1 / IH / tan(FOV / 2) < 1.9. By satisfying the above range, the balance between the size of the optical lens and the field of view and the image surface can be ensured.

[0069] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.7 < f1 / f < -1.0. By satisfying the above range, the first lens can have appropriate negative refractive power, which can balance the working aperture of the first lens and the size of the image surface and the field of view.

[0070] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 3.0 < f2 / f < 6.0. By satisfying the above range, the second lens can have appropriate positive refractive power, which can make the light trend stable and be beneficial to balance the aberration caused by the negative refractive power of the first lens, i.e., can correct the edge aberration of the optical lens and improve the imaging resolution.

[0071] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: f3 / f < -5.0. By satisfying the above range, the third lens can have negative refractive power, which is beneficial to the smooth transition of light and balances various aberrations generated by the third lens itself, thereby improving the imaging quality of the optical system.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.0 < f4 / f < 2.0. By satisfying the above range, the fourth lens can have appropriate positive refractive power, which is beneficial to improve the light convergence ability of the optical lens, and at the same time can balance the aberration of the optical lens and improve the imaging quality of the optical lens.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.0 < f5 / f < 1.5. By satisfying the above range, the fifth lens can have appropriate positive refractive power, which is beneficial to improve the light convergence ability of the optical lens, and at the same time can balance the aberration of the optical lens and improve the imaging quality of the optical lens.

[0074] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.5 < f6 / f < -0.5. Satisfying the above range, the sixth lens can have a proper negative focal length, the light ray trend can be smoothly transitioned, and the imaging quality of the optical lens can be improved.

[0075] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: f7 / f < -1.0. Satisfying the above range, the seventh lens can have a negative focal length, the imaging area of the optical lens can be increased, and the imaging quality of the optical lens can be improved.

[0076] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: f8 / f > 1.0. Satisfying the above range, the eighth lens can have a positive focal length, various aberrations can be balanced, and the imaging quality of the optical lens can be improved.

[0077] In some embodiments, the fifth lens and the sixth lens can be glued to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, improve the imaging quality of the optical lens, reduce the assembly sensitivity of the optical lens, and further reduce the processing difficulty of the optical lens and improve the assembly yield of the optical lens.

[0078] In order to make the system have better optical performance, a plurality of aspheric lenses are used in the lens, and the shape of each aspheric surface of the optical lens satisfies the following equation:

[0079]

[0080] Wherein, z is the distance of the curved surface and 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, A, B, C, D, E, F are the second-order, fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order curved surface coefficients, respectively.

[0081] The application will be further described in the following embodiments. In each embodiment, 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 application, but the embodiments of the application are not limited to the following embodiments only, any change, replacement, combination or simplification made without departing from the innovative points of the application should be regarded as equivalent replacement mode, and all are included in the protection scope of the application.

[0082] Embodiment 1

[0083] Please refer to Figure 1Fig. 1 is a structural schematic diagram of an optical lens provided in Embodiment 1 of the present application, which comprises, along an optical axis from an object side to an imaging surface, a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter G1 and a protective glass G2.

[0084] The first lens L1 has a negative focal power, and both the object side S1 and the image side S2 thereof are concave surfaces;

[0085] The second lens L2 has a positive focal power, and the object side S3 thereof is a concave surface, and the image side S4 thereof is a convex surface;

[0086] The third lens L3 has a negative focal power, and the object side S5 thereof is a convex surface, and the image side S6 thereof is a concave surface;

[0087] The stop ST;

[0088] The fourth lens L4 has a positive focal power, and both the object side S7 and the image side S8 thereof are convex surfaces;

[0089] The fifth lens L5 has a positive focal power, and both the object side S9 and the image side S10 thereof are convex surfaces;

[0090] The sixth lens L6 has a negative focal power, and both the object side S10 and the image side S11 thereof are concave surfaces;

[0091] The fifth lens L5 and the sixth lens L6 constitute a cemented lens group, and the cemented surface S10 is between the image side of the fifth lens L5 and the object side of the sixth lens L6;

[0092] The seventh lens L7 has a negative focal power, and the object side S12 thereof is a concave surface, and the image side S13 thereof is a convex surface;

[0093] The eighth lens L8 has a positive focal power, and both the object side S14 and the image side S15 thereof are convex surfaces;

[0094] Both the object side S16 and the image side S17 of the filter G1 are flat surfaces;

[0095] Both the object side S18 and the image side S19 of the protective glass G2 are flat surfaces;

[0096] The imaging surface S20 is a flat surface.

[0097] The related parameters of the lenses in the optical lens in Embodiment 1 are shown in Table 1-1.

[0098] Table 1-1

[0099]

[0100]

[0101] The surface parameters of the aspherical lens of the optical lens in Example 1 are shown in Table 1-2.

[0102] Table 1-2

[0103] Surface number K A B C D E F S5 -3.07E+00 0.00E+00 -5.13E-04 7.17E-06 -3.95E-07 8.57E-09 -5.10E-11 S6 -1.52E+01 0.00E+00 -2.20E-03 4.08E-05 -2.92E-07 -1.51E-09 3.48E-11 S7 -5.33E+00 0.00E+00 -5.63E-04 -5.23E-06 7.27E-07 -9.81E-09 1.07E-11 S8 -1.00E+01 0.00E+00 2.24E-04 -1.30E-05 1.12E-07 4.79E-09 -9.43E-11 S14 -1.94E+00 0.00E+00 1.93E-04 5.33E-06 -1.30E-07 2.49E-09 -1.84E-11 S15 4.65E+00 0.00E+00 5.73E-04 6.65E-06 -3.76E-08 1.57E-09 -1.59E-11

[0104] In this embodiment, the field curvature curve, F-Tanθ distortion curve, relative illumination curve, MTF curve, axial aberration curve, and transverse aberration curve of the optical lens are shown in FIGS. 1-1 to 1-5, respectively. Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7

[0105] Figure 2 The field curvature curve of Example 1 is shown, which represents the curvature of light rays of different wavelengths on the meridional image surface and 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 -0.08 mm ~ 0.06 mm, which shows that the optical lens can well correct the field curvature.

[0106] Figure 3 The F-Tanθ distortion curve of Example 1 is shown, which represents the F-Tanθ distortion of light rays of different wavelengths on the imaging surface at different image heights, the horizontal axis represents the F-Tanθ distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within -40% ~ 0, the image compression in the edge angle region is relatively flat, and the clarity of the expanded image is effectively improved.

[0107] Figure 4 The relative illumination curve of Example 1 is shown, which represents the relative illumination 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 illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 70% at the maximum half field angle, which shows that the optical lens has good relative illumination.

[0108] Figure 5 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of this embodiment is above 0.4 within the full field of view, and within the range of 0 ~ 160 lp / mm, the MTF curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low frequency and high frequency cases.​

[0109] Figure 6 The axial aberration curve of the optical lens of Example 1 is shown in FIG. 2, which represents the aberration of the optical axis at the imaging plane at each wavelength, and the horizontal axis represents the axial aberration value (unit: μm), 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 -30 μm-10 μm, which indicates that the optical lens can well correct the axial aberration.

[0110] Figure 7 The axial aberration curve of the optical lens of Example 1 is shown in FIG. 2, which represents the aberration of the optical axis at the imaging plane at each wavelength, and the horizontal axis represents the axial aberration value (unit: μm), 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 -30 μm-10 μm, which indicates that the optical lens can well correct the axial aberration.

[0111] Example 2

[0112] Please refer to Figure 8 , which is a schematic structural diagram of the optical lens provided in Example 2 of the present application. The optical lens of the present embodiment is substantially the same as that of Example 1, and the difference mainly lies in that the object side S3 of the second lens L2 is a convex surface, and the optical parameters such as the curvature radius, asphericity coefficient and thickness of each lens surface are different.

[0113] The related parameters of each lens in the optical lens of Example 2 are shown in Table 2-1.

[0114] Table 2-1

[0115]

[0116]

[0117] The surface type parameters of the aspheric lenses of the optical lens of Example 2 are shown in Table 2-2.

[0118] Table 2-2

[0119] Surface number K A B C D E F S5 -1.63E+00 0.00E+00 -7.15E-04 6.07E-06 -1.23E-07 2.40E-09 -7.81E-12 S6 -5.94E-02 0.00E+00 -1.51E-03 1.37E-05 -5.47E-07 1.04E-08 -1.38E-10 S7 -3.03E-01 0.00E+00 -1.98E-04 8.63E-06 -3.33E-07 8.70E-09 -8.44E-11 S8 1.85E+00 0.00E+00 2.70E-04 7.37E-06 -1.15E-07 6.57E-09 -6.77E-11 S14 1.81E-01 0.00E+00 2.65E-04 3.31E-06 -6.84E-08 1.14E-09 -4.98E-12 S15 1.07E+00 0.00E+00 5.68E-04 5.18E-06 -3.12E-09 -7.93E-10 7.78E-12

[0120] In the present embodiment, the field curvature curve, F-Tanθ distortion curve, relative luminance curve, MTF curve, axial aberration curve and axial aberration curve of the optical lens are shown in FIGS. Figure 9 、 Figure 10 、 Figure 11 、 Figure 12 、 Figure 13 、 Figure 14 .

[0121] Figure 9 The field curvature curve of Example 2 is shown, which represents the curvature 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 -0.08mm~0.04mm, which shows that the optical lens can well correct the field curvature.

[0122] Figure 10 The F-Tanθ distortion curve of Example 2 is shown, which represents the F-Tanθ distortion of light rays of different wavelengths at different image heights on the imaging surface, the horizontal axis represents the F-Tanθ distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within -40%~0, the image compression in the edge angle region is relatively flat, and the clarity of the expanded image is effectively improved.

[0123] Figure 11 The relative luminance curve of Example 2 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 70% at the maximum half field angle, which shows that the optical lens has good relative luminance.

[0124] Figure 12 The MTF (Modulation Transfer Function) curve of Example 2 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the present embodiment is above 0.4 within the full field of view, and within the range of 0~160lp / 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 low and high frequency conditions.

[0125] Figure 13 The axial aberration curve of Example 2 is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within -15μm~10μm, which shows that the optical lens can well correct the axial aberration.

[0126] Figure 14The diagram shows the transverse chromatic aberration curves for Example 2, representing the chromatic aberration of each wavelength relative to the center wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the diagram, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2 μm to 3 μm, indicating that the optical lens can excellently correct chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane.

[0127] Example 3

[0128] Please see Figure 15 The figure shows a schematic diagram of the structure of the optical lens provided in Embodiment 3 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 S1 of the first lens L1 is convex, the object side surface S3 of the second lens L2 is convex, and the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0129] The relevant parameters of each lens in the optical lens of Example 3 are shown in Table 3-1.

[0130] Table 3-1

[0131]

[0132]

[0133] The surface profile parameters of the aspherical lens in Example 3 are shown in Table 3-2.

[0134] Table 3-2

[0135] Surface number K A B C D E F S5 2.71E+00 0.00E+00 -5.76E-04 3.66E-06 9.33E-08 1.44E-10 -5.58E-12 S6 -2.50E-02 0.00E+00 -1.05E-03 3.09E-05 -4.69E-07 -4.05E-09 2.37E-10 S7 2.87E-01 0.00E+00 -8.71E-05 9.89E-06 3.62E-07 4.13E-08 -3.92E-10 S8 -6.42E+00 0.00E+00 5.11E-04 -9.09E-06 5.87E-07 8.29E-08 -2.64E-09 S14 1.23E+01 0.00E+00 6.87E-04 1.35E-05 -5.61E-08 1.03E-09 -1.34E-10 S15 -8.95E+00 0.00E+00 7.68E-04 2.75E-05 7.40E-07 -2.88E-08 -1.31E-10

[0136] In this embodiment, the field curvature curve, F-Tanθ distortion curve, relative illumination curve, MTF curve, axial aberration curve, and transverse chromatic aberration curve of the optical lens are respectively as follows: Figure 16 , Figure 17 , Figure 18 , Figure 19 , Figure 20 , Figure 21 As shown.

[0137] Figure 16 The field curvature curve of Example 3 is shown, which represents the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within -0.04 mm to 0.02 mm, indicating that the optical lens can effectively correct the field curvature.

[0138] Figure 17 The F-Tanθ distortion curve of Example 3 is shown, which represents the F-Tanθ distortion of light rays of different wavelengths at different image heights on the imaging plane. The horizontal axis represents the F-Tanθ distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within -15%~0, the image compression in the edge angle region is relatively gentle, and the clarity of the expanded image is effectively improved.

[0139] Figure 18 The relative illumination curve of Example 3 is shown, which represents the relative illumination value of different field angles on the imaging plane. The horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 70% at the maximum half field angle, indicating that the optical lens has good relative illumination.

[0140] Figure 19 The MTF (Modulation Transfer Function) curve of Example 3 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the present embodiment is above 0.4 within the full field of view, and in the range of 0~160 lp / mm, the MTF curve uniformly and smoothly decreases from the center to the edge field of view, and has good imaging quality and good detail resolution ability in both low and high frequency cases.

[0141] Figure 20 The axial aberration curve of Example 3 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: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within -5μm~10μm, indicating that the optical lens can better correct the axial aberration.

[0142] Figure 21 The axial aberration curve of Example 3 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: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within -5μm~10μm, indicating that the optical lens can better correct the axial aberration.

[0143] Please refer to Table 4 for the optical characteristics of the above-mentioned embodiments, including the effective focal length f, the total track length TTL, the aperture value FNO, the image height IH, the chief ray angle CRA, the object-side entrance pupil diameter D1 of the first lens, the maximum field of view FOV of the optical lens, and the numerical values corresponding to each conditional expression in the embodiments.

[0144] Table 4

[0145]

[0146]

[0147] In summary of the above embodiments, the optical lens provided by the present application improves the imaging quality of the optical lens, reduces aberration, and improves the imaging quality of the optical lens by reasonable configuration of the surface shape of each lens and reasonable matching of the optical power.

[0148] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a 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.

[0149] The above-described 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 scope of the patent of the present application. It should be noted that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to 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 comprising eight lenses, characterized in that, Along the optical axis from the object side to the imaging plane, the following are included in sequence: The first lens with negative optical power has a concave image-side surface. A second lens with positive optical power has a convex image-side surface. A third lens with negative optical power has a convex object side and a concave image side. The fourth lens with positive optical power has convex surfaces on both its object side and image side. The fifth lens with positive optical power has convex surfaces on both its object side and image side. The sixth lens has negative optical power, and both its object-side and image-side surfaces are concave. The seventh lens with negative optical power has a concave object side and a convex image side. The eighth lens, which has positive optical power, has convex surfaces on both its object side and image side. The object-side radius of curvature R7 and the image-side radius of curvature R8 of the fourth lens satisfy: -10.0 < (R7 - R8) / (R7 + R8) < -2.0; The object-side radius of curvature R5 and the image-side radius of curvature R6 of the third lens satisfy the following condition: 0.01 < (R5 - R6) / (R5 + R6) < 0.

25.

2. The optical lens according to claim 1, characterized in that, The total optical length (TTL) and effective focal length (f) of the optical lens satisfy the condition: 5.14 ≤ TTL / f < 5.

5.

3. The optical lens according to claim 1, characterized in that, The effective focal length f, maximum field of view FOV, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy the following condition: 0.6 < (IH / 2) / (f × tan(FOV / 2)) < 0.

9.

4. The optical lens according to claim 1, characterized in that, The maximum field of view (FOV) and aperture value (FNO) of the optical lens satisfy: 35° <FOV / FNO<70°。 5. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view satisfy: 1.4 <IH / f<1.8。 6. The optical lens according to claim 1, characterized in that, The effective focal length f and the optical back focal length BFL of the optical lens satisfy: 0.4 <BFL / f<0.7。 7. The optical lens according to claim 1, characterized in that, The maximum field of view (FOV) and effective focal length (f) of the optical lens satisfy: 10.0° / mm <FOV / f<15.0° / mm。 8. The optical lens according to claim 1, characterized in that, The object-side radius of curvature R1 of the first lens and the image-side radius of curvature R2 of the first lens satisfy: 0.5 < (R1-R2) / (R1+R2) < 1.

5.

9. The optical lens according to claim 1, characterized in that, The focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 3.0 <f2 / f<6.0。 10. The optical lens according to claim 1, characterized in that, The total optical length TTL of the optical lens and the sum of the center thicknesses of the first lens to the eighth lens along the optical axis, ∑CT, satisfy the condition: 0.4 < ∑CT / TTL < 0.6.

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