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 image side surface of the second lens is a convex surface; a third lens with negative optical power, wherein the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; a fourth lens with positive optical power, wherein the object side surface and the image side surface of the fourth lens are both convex surfaces; 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 negative optical power, wherein the object side surface of the seventh lens is a concave surface; and an eighth lens with positive optical power, wherein the image side surface of the eighth lens is a convex surface. 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, in particular to an optical lens. BACKGROUND

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

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

[0004] In view of the above problems, the purpose of the present application is to provide an optical lens with 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, both the object side and the image side are 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, both the object side and the image side are convex;

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

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

[0013] The seventh lens with negative focal power, the object side is concave;

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

[0015] The object side curvature radius R3 of the second lens and the image side curvature radius R4 of the second lens satisfy: (R3-R4) / (R3+R4)>0.5.

[0016] Further preferably, the optical 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: 0.55 < (IH / 2) / (f x tan(FOV / 2)) < 0.7.

[0018] Further preferably, the maximum field of view angle FOV of the optical lens and the aperture value FNO satisfy: 60° < FOV / FNO < 80°.

[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: 1.5 < IH / f < 2.2.

[0020] Further preferably, the effective focal length f of the optical lens and the optical back focal length BFL satisfy: 0.6 < BFL / f < 1.0.

[0021] Further preferably, the maximum field of view angle FOV of the optical lens and the effective focal length f satisfy: 12.0 < FOV / f < 16.0.

[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: 1.0 < (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 optical 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: 0.5 < ∑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 FIG. 1 is a structure schematic diagram of an optical lens according to an embodiment of the present application.

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

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

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

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

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

[0033] Figure 7 Vignetting curve of the optical lens in the embodiment 1 of the present application.

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

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

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

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

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

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

[0040] Figure 14 Vignetting curve of the optical lens in the embodiment 2 of the present application.

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

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

[0043] Figure 17 F-Tanθ distortion curve of the optical lens in the embodiment 3 of the present application.

[0044] Figure 18A relative illumination curve for the optical lens of Example 3 of the present application.

[0045] Figure 19 An MTF curve for the optical lens of Example 3 of the present application.

[0046] Figure 20 An axial aberration curve for the optical lens of Example 3 of the present application.

[0047] Figure 21 A lateral chromatic aberration curve for the optical lens of Example 3 of the present application.

[0048] Figure 22 A structure diagram of an optical lens of Example 4 of the present application.

[0049] Figure 23 A field curvature curve for the optical lens of Example 4 of the present application.

[0050] Figure 24 An F-TanΘ distortion curve for the optical lens of Example 4 of the present application.

[0051] Figure 25 A relative illumination curve for the optical lens of Example 4 of the present application.

[0052] Figure 26 An MTF curve for the optical lens of Example 4 of the present application.

[0053] Figure 27 An axial aberration curve for the optical lens of Example 4 of the present application.

[0054] Figure 28 A lateral chromatic aberration curve for the optical lens of Example 4 of the present application.

[0055] The present application will be further described with reference to the following detailed description in connection with the above described drawings. DETAILED DESCRIPTION

[0056] For a better understanding of the present application, various aspects of the present application will be described in connection with the accompanying drawings. It should be appreciated that these descriptions which follow are only examples of the various embodiments of the application and simply provide explanations of the aspects of the application. These descriptions are not intended to limit the scope of the application in any way. Throughout the description similar reference numerals will be used to denote like parts throughout the description. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0057] It should be noted that the expressions first, second, third and the like used in this specification are used only to distinguish one feature from another, and do not denote 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.

[0058] In the drawings, the thickness, size, and shape of the lenses have been exaggerated slightly for ease 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.

[0059] In this document, the paraxial region refers to a region near the optical axis. If the 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 the 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 imaging surface is referred to as the image side surface of the lens.

[0060] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, specify 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 features, the phrase is intended to be interpreted to mean that the features in the list are among the possible features, and that one or more of the features in the list can be present, but not necessarily all of the features in the list. Furthermore, when describing embodiments of the present application, the word "may" means "one or more embodiments of the present application". Also, the word "exemplary" is intended to mean an example or an illustration.

[0061] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that the terms 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.

[0062] 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 drawings and in conjunction with embodiments.

[0063] The optical lens of the embodiment 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 fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a filter, and a protective glass. A diaphragm is provided between the third lens and the fourth lens, or between the second lens and the third lens.

[0064] In some embodiments, the first lens can have negative focal power, both the object side surface and the image side surface of which are concave. The second lens can have positive focal power, the image side surface of which is convex. The third lens can have negative focal power, the object side surface of which is convex and the image side surface of which is concave. The fourth lens can have positive focal power, both the object side surface and the image side surface of which are convex. The fifth lens can have positive focal power, both the object side surface and the image side surface of which are convex. The sixth lens can have negative focal power, both the object side surface and the image side surface of which are concave. The seventh lens can have negative focal power, the object side surface of which is concave. The eighth lens can have positive focal power, the image side surface of which is convex.

[0065] 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: (R3-R4) / (R3+R4)>0.5. Satisfying the above range is conducive to balancing the on-axis aberration of the optical lens, reducing the correction difficulty of the subsequent lens spherical aberration and positional chromatic aberration; at the same time, it is conducive to the smoothness of the light ray trend, and as many edge field beams as possible are transmitted to the rear end of the optical lens, thereby improving the relative luminance of the optical lens.

[0066] In some embodiments, the total optical 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.

[0067] 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: 0.55<(IH / 2) / (fxtan(FOV / 2))<0.7. Satisfying the above requirement indicates that the optical distortion of the optical lens is well controlled, thereby improving the resolving power of the optical lens.

[0068] In some embodiments, the maximum field of view angle FOV of the optical lens and the aperture value FNO satisfy: 60°<FOV / FNO<80°. 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, meets the demand of large range detection, and is conducive to improving the problem of rapid decline of relative brightness of the edge field of view, thereby also conducive to obtaining more scene information.

[0069] 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: 1.5<IH / f<2.2. Satisfying the above range can realize wide-angle characteristics, thereby meeting the demand of large range shooting, and can also realize large image surface characteristics, thereby improving the imaging quality of the optical lens.

[0070] In some embodiments, the effective focal length f of the optical lens and the optical back focal length BFL satisfy: 0.6 < BFL / f < 1.0. Satisfying the above range can reduce the interference of aberrations such as aberration and coma, and improve the resolution and clarity of imaging; and improve the stability of the optical lens.

[0071] In some embodiments, the maximum field of view FOV of the optical lens and the effective focal length f satisfy: 12.0 < FOV / f < 16.0. Satisfying the above range enables the optical lens to capture a target farther away.

[0072] In some embodiments, the object side surface radius of curvature R1 of the first lens and the image side surface radius of curvature R2 of the first lens satisfy: 1.0 < (R1-R2) / (R1+R2) < 1.5. Satisfying the above range can control the direction of light rays, reduce spherical aberration, correct coma, increase light utilization, and improve stability.

[0073] In some embodiments, the object side surface radius of curvature R5 of the third lens and the image side surface radius of curvature R6 of the third lens satisfy: 0.01 < (R5-R6) / (R5+R6) < 0.25. Satisfying the above range can converge edge field of view light rays, help optimize imaging performance in low light conditions, and provide better image brightness and contrast.

[0074] In some embodiments, the total length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis satisfy: 0.5 < ∑CT / TTL < 0.6. Satisfying the above range can compress the total length of the optical system, so that the structure of the system is more compact.

[0075] 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 object side surface aperture D1 of the first lens satisfy: 0.5 < D1 / IH / tan(FOV / 2) < 1.0. Satisfying the above range can ensure the balance between the size of the optical lens and the field of view, and the image plane.

[0076] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.5 < f1 / f < -1.0. Satisfying the above range can make the first lens have appropriate negative focal power, and can balance the working aperture of the first lens and the size of the image plane and the field of view.

[0077] 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 < 10.0. Satisfying the above range can make the second lens have appropriate positive focal power, so that the light rays are stable, which is conducive to balancing 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.

[0078] 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. Satisfying the above range, the third lens can have negative refractive power, which is conducive to smooth transition of light rays and balancing various aberrations generated by the third lens itself, thereby improving the imaging quality of the optical system.

[0079] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.0

[0080] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.0

[0081] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -3.0

[0082] 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 negative refractive power, which is conducive to increasing the imaging area of the optical lens and improving the imaging quality of the optical lens.

[0083] 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 positive refractive power, which is conducive to balancing various aberrations and improving the imaging quality of the optical lens.

[0084] In some embodiments, the fifth lens and the sixth lens can be bonded to form a bonded lens, which can effectively correct chromatic aberration of the optical lens, reduce sensitivity of the optical lens to decentration, balance 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.

[0085] In order to make the system have better optical performance, multiple aspheric lenses are used in the lens, and the shape of each aspheric surface of the optical lens satisfies the following equation:

[0086]

[0087] wherein z is the distance of the curved surface to the vertex of the curved surface 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 vertex of the curved surface, K is the coefficient of the quadratic curved surface, and A, B, C, D, E, and F are the coefficients of the second-order, fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order curved surfaces, respectively.

[0088] 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 merely the preferred embodiments of the application, but the embodiments of the application are not limited to the following embodiments only, and any change, substitution, combination, or simplification made without departing from the innovative points of the application should be regarded as equivalent replacement, and should be included in the protection scope of the application.

[0089] Embodiment 1

[0090] Please refer to Figure 1 , which is a structural schematic diagram of the optical lens provided in the embodiment 1 of the application. The optical lens comprises, along the optical axis from the object side to the 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.

[0091] The first lens L1 has a negative focal power, and both the object side surface S1 and the image side surface S2 are concave surfaces;

[0092] The second lens L2 has a positive focal power, the object side surface S3 is a concave surface, and the image side surface S4 is a convex surface;

[0093] The third lens L3 has a negative focal power, the object side surface S5 is a convex surface, and the image side surface S6 is a concave surface;

[0094] The stop ST;

[0095] The fourth lens L4 has a positive focal power, and both the object side surface S7 and the image side surface S8 are convex surfaces;

[0096] The fifth lens L5 has a positive focal power, and both the object side surface S9 and the image side surface S10 are convex surfaces;

[0097] The sixth lens L6 has a negative focal power, and both the object side surface S10 and the image side surface S11 are concave surfaces;

[0098] The fifth lens L5 and the sixth lens L6 form a cemented lens group, and the cemented surface of the image side surface of the fifth lens L5 and the object side surface of the sixth lens L6 is S10;

[0099] The seventh lens L7 has negative refractive power, the object side S12 is a concave surface, and the image side S13 is a convex surface;

[0100] The eighth lens L8 has positive refractive power, the object side S14 and the image side S15 are both convex surfaces;

[0101] The object side S16 and the image side S17 of the filter G1 are both flat surfaces;

[0102] The object side S18 and the image side S19 of the protective glass G2 are both flat surfaces;

[0103] The imaging surface S20 is a flat surface.

[0104] The related parameters of each lens in the optical lens in Embodiment 1 are shown in Table 1-1.

[0105] Table 1-1

[0106]

[0107] The surface type parameters of the aspherical lens of the optical lens in Embodiment 1 are shown in Table 1-2.

[0108] Table 1-2

[0109]

[0110]

[0111] In this embodiment, the field curvature curve, F-Tanθ distortion curve, relative luminance curve, MTF curve, axial aberration curve, and transverse chromatic aberration curve of the optical lens are shown in FIGS. Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7

[0112] Figure 2 The field curvature curve of Embodiment 1 is shown, which represents the curvature 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-0.08mm-0.06mm, which shows that the optical lens can well correct the field curvature.

[0113] Figure 3 ​The F-Tanθ distortion curve of the embodiment 1 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 -40%~0, the image compression in the edge angle region is relatively gentle, and the clarity of the expanded image is effectively improved.

[0114] Figure 4 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 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.

[0115] Figure 5 The MTF (Modulation Transfer Function) curve of the embodiment 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 the embodiment is above 0.4 within the full field of view, and the MTF curve uniformly and smoothly decreases from the center to the edge field of view within the range of 0~160 lp / mm, and has good imaging quality and good detail resolution ability in low and high frequency conditions.

[0116] Figure 6 The axial aberration curve of the embodiment 1 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 -30 μm~10 μm, indicating that the optical lens can better correct the axial aberration.

[0117] Figure 7 The sagittal chromatic aberration curve of the embodiment 1 is shown, which represents the chromatic aberration of each wavelength at different image heights on the imaging plane relative to the center wavelength (0.55 μm). The horizontal axis represents the sagittal chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field angle. As can be seen from the figure, the sagittal chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -1.5 μm~2.5 μm, indicating that the optical lens can very well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0118] Embodiment 2

[0119] Please refer to Figure 8Figure 2 shows a structural schematic diagram of an optical lens provided in Embodiment 2 of the present application. The optical lens of the present embodiment is substantially the same as that of Embodiment 1, except 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, thickness, etc. of each lens surface type are different.

[0120] The related parameters of each lens in the optical lens of Embodiment 2 are shown in Table 2-1.

[0121] Table 2-1

[0122]

[0123] The surface type parameters of the aspheric lenses of the optical lens of Embodiment 2 are shown in Table 2-2.

[0124] Table 2-2

[0125]

[0126]

[0127] In the present embodiment, the field curvature curve, F-Tanθ distortion curve, relative luminance curve, MTF curve, axial aberration curve, and transverse chromatic aberration curve of the optical lens are shown in Figures 2-1, 2-2, 2-3, 2-4, 2-5, and 2-6, respectively. Figure 9 、 Figure 10 、 Figure 11 、 Figure 12 、 Figure 13 、 Figure 14

[0128] Figure 9 Figure 2-1 shows the field curvature curve of Embodiment 2, which indicates the curvature degree 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 sagittal image surface is controlled within -0.08 mm-0.04 mm, which indicates that the optical lens can well correct the field curvature.

[0129] Figure 10 Figure 2-2 shows the F-Tanθ distortion curve of Embodiment 2, which indicates 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 definition of the expanded image is effectively improved.

[0130] Figure 11 ​The relative luminance curve of the embodiment 2 is shown, which represents the relative luminance values of different field angles on the imaging plane, 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 indicates that the optical lens has good relative luminance.

[0131] Figure 12 The MTF (modulation transfer function) curve of the embodiment 2 is shown, which represents the lens imaging modulation degree of different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the embodiment is above 0.4 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 capability in the case of low frequency and high frequency.

[0132] Figure 13 The axial aberration curve of the embodiment 2 is shown, which represents the axial 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 -15 μm-10 μm, which indicates that the optical lens can better correct the axial aberration.

[0133] Figure 14 The axial aberration curve of the embodiment 2 is shown, which represents the axial 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 -15 μm-10 μm, which indicates that the optical lens can better correct the axial aberration.

[0134] Embodiment 3

[0135] Please refer to Figure 15 , which is a structural schematic diagram of the optical lens provided in the embodiment 3 of the present application, and the optical lens of the embodiment is substantially the same as that of the embodiment 1, and the main difference is that the diaphragm ST is arranged between the second lens L2 and the third lens L3, the image side surface S13 of the seventh lens L7 is a concave surface, the object side surface S14 of the eighth lens L8 is a concave surface, and the optical parameters such as the curvature radius, the aspheric coefficient and the thickness of each lens surface are different.

[0136] The related parameters of each lens in the optical lens in the embodiment 3 are shown in Table 3-1.

[0137] Table 3-1

[0138]

[0139] The surface parameters of the aspherical lens of the optical lens in Example 3 are shown in Table 3-2.

[0140] Table 3-2

[0141]

[0142]

[0143] 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 shown in FIGS. 3-1 to 3-6, respectively. Figure 16 、 Figure 17 、 Figure 18 、 Figure 19 、 Figure 20 、 Figure 21

[0144] Figure 16 The field curvature curve of Example 3 is shown, which represents the curvature of the meridional image surface and the sagittal image surface of light rays of different wavelengths, 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 -0.12mm~0.03mm, which shows that the optical lens can well correct the field curvature.

[0145] 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 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 -45%~0, the image compression in the edge angle region is relatively flat, and the clarity of the expanded image is effectively improved.

[0146] Figure 18 The relative illumination curve of Example 3 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 60% at the maximum half field angle, which shows that the optical lens has good relative illumination.

[0147] Figure 19 ​The MTF (Modulation Transfer Function) curve of the embodiment 3 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 0.2 in 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 capability in the case of low frequency and high frequency.

[0148] Figure 20 The axial aberration curve of the embodiment 3 is shown, which represents the aberration of the optical axis at the imaging surface at each wavelength, the horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the shift amount of the axial aberration is controlled within-40 μm-30 μm, which indicates that the optical lens can better correct the axial aberration.

[0149] Figure 21 The curve of the embodiment 3 is shown, which represents the color difference of different image heights on the imaging surface at each wavelength relative to the center wavelength (0.55 μm), the horizontal axis represents the vertical color difference value (unit: μm) of each wavelength relative to the center wavelength, and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical color difference of the longest wavelength and the shortest wavelength is controlled within-4 μm-4 μm, which indicates that the optical lens can very well correct the color difference of the edge field of view and the secondary spectrum of the entire image surface.

[0150] Embodiment 4

[0151] Please refer to Figure 22 , which is a structural schematic diagram of the optical lens provided in the embodiment 4 of the present application, and the optical lens of the embodiment is substantially the same as that of the embodiment 1, and the main difference is that the diaphragm ST is arranged between the second lens L2 and the third lens L3, the object side S3 of the second lens L2 is a convex surface, the image side S13 of the seventh lens L7 is a concave surface, and the optical parameters such as the curvature radius, the asphericity coefficient and the thickness of each lens surface are different.

[0152] The related parameters of each lens in the optical lens in the embodiment 4 are shown in Table 4-1.

[0153] Table 4-1

[0154]

[0155] The surface type parameters of the aspheric lens of the optical lens in the embodiment 4 are shown in Table 4-2.

[0156] Table 4-2

[0157]

[0158]

[0159] In the present 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 shown in FIGS. 1-5, respectively. Figure 23 、 Figure 24 、 Figure 25 、 Figure 26 、 Figure 27 、 Figure 28

[0160] Figure 23 The field curvature curve of Example 4 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 -0.12 mm~0.12 mm, which shows that the optical lens can well correct the field curvature.

[0161] Figure 24 The F-Tanθ distortion curve of Example 4 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.

[0162] Figure 25 The relative illumination curve of Example 4 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 60% at the maximum half field angle, which shows that the optical lens has good relative illumination.

[0163] Figure 26 The MTF (Modulation Transfer Function) curve of Example 4 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 0.2 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.

[0164] Figure 27 ​The axial aberration curve of the embodiment 4 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 shift of the axial aberration is controlled within -15 μm ~ 25 μm, which shows that the optical lens can correct the axial aberration well.

[0165] Figure 28 The curve of the axial aberration of the embodiment 4 is shown, which represents the color aberration of each wavelength at different image heights on the imaging plane relative to the central wavelength (0.55 μm), the horizontal axis represents the axial aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. As can be seen from the figure, the axial aberration of the longest wavelength and the shortest wavelength is controlled within -4 μm ~ 5 μm, which shows that the optical lens can correct the color aberration of the edge field and the secondary spectrum of the whole image plane very well.

[0166] Referring to Table 5, the optical characteristics corresponding to the above-mentioned embodiments are shown, including the effective focal length f, the total optical length TTL, the aperture value FNO, the real image height IH, the chief ray angle CRA, the maximum field angle FOV, and the numerical value corresponding to each conditional expression in each embodiment of the optical lens.

[0167] Table 5

[0168] Parameter and conditional expression Example 1 Example 2 Example 3 Example 4 f (mm) 7.85 7.98 9.81 8.67 FOV (°) 106.00 106.00 120.00 109.1 EPD (mm) 4.91 4.98 6.13 6.19 TTL (mm) 42.00 42.00 51.76 42.02 FNO 1.60 1.60 1.60 1.40 IH (mm) 13.90 13.82 20.04 16.18 CRA (°) 20.00 20.00 24.57 20.02 BFL (mm) 5.10 5.18 9.54 8.31 D1 (mm) 17.35 10.77 21.44 17.56 TTL / f 5.35 5.27 5.28 4.85 (IH / 2) / (f x tan(FOV / 2)) 0.67 0.65 0.59 0.66 FOV / FNO 66.25 66.25 75.00 77.93 IH / f 1.77 1.73 2.04 1.87 BFL / f 0.65 0.65 0.97 0.96 FOV / f 13.50 13.29 12.23 12.58 f1 / f -1.28 -1.16 -1.29 -1.24 f2 / f 5.17 3.84 8.67 3.57 f3 / f -11.76 -5.57 -27.52 -12.68 f4 / f 1.38 1.44 1.87 2.22 f5 / f 1.38 1.35 1.50 1.60 f6 / f -1.10 -1.26 -1.69 -2.75 f7 / f -1.63 -1.62 -10.28 -1.44 f8 / f 1.46 1.57 13.13 1.63 (R1-R2) / (R1+R2) 1.23 1.28 1.07 1.09 (R3-R4) / (R3+R4) 0.79 2.06 0.57 63.04 (R5-R6) / (R5+R6) 0.20 0.20 0.08 0.09 ∑CT / TTL 0.53 0.54 0.51 0.53 D1 / IH / tan(FOV / 2) 0.94 0.59 0.62 0.77

[0169] In summary of the above embodiments, the optical lens provided by the present application improves the imaging quality of the optical lens, reduces the aberration, and improves the imaging quality of the optical lens by reasonable configuration of each lens surface and reasonable matching of the optical power.

[0170] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0171] The above-described embodiments only express several embodiments of the present application, which are described in a more specific and detailed manner, but cannot 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, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An optical lens, eight pieces of lenses in total, characterized in that, In order from the object side to the imaging surface along the optical axis, the optical lens comprises in sequence: a first lens with negative refractive power, both the object side surface and the image side surface of which are concave; a second lens with positive refractive power, the image side surface of which is convex; a third lens with negative refractive power, the object side surface of which is convex and the image side surface of which is concave; a fourth lens with positive refractive power, both the object side surface and the image side surface of which are 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 negative refractive power, the object side surface of which is concave; an eighth lens with positive refractive power, the image side surface of which is convex; a radius of curvature R3 of the object side surface of the second lens and a radius of curvature R4 of the image side surface of the second lens satisfy: 0.5 < (R3-R4) / (R3+R4) ≤ 63.04; a radius of curvature R5 of the object side surface of the third lens and a radius of curvature R6 of the image side surface of the third lens satisfy: 0.01 < (R5-R6) / (R5+R6) < 0.

25.

2. The optical lens of claim 1, wherein, an optical total length TTL of the optical lens and an effective focal length f satisfy: 4.85 ≤ TTL / f < 5.

5.

3. The optical lens of claim 1, wherein, an effective focal length f of the optical lens, a maximum field of view FOV and a real image height IH corresponding to the maximum field of view satisfy: 0.55 < (IH / 2) / (f*tan(FOV / 2)) < 0.

7.

4. The optical lens of claim 1, wherein, a maximum field of view FOV of the optical lens and an aperture value FNO satisfy: 60° < FOV / FNO < 80°.

5. The optical lens of claim 1, wherein, an effective focal length f of the optical lens and a real image height IH corresponding to the maximum field of view satisfy: 1.5 < IH / f < 2.

2.

6. The optical lens of claim 1, wherein, an effective focal length f of the optical lens and an optical back focal length BFL satisfy: 0.6 < BFL / f < 1.

0.

7. The optical lens of claim 1, wherein, a maximum field of view FOV of the optical lens and an effective focal length f satisfy: 12.0° / mm < FOV / f < 16.0° / mm.

8. The optical lens of claim 1, wherein, a radius of curvature R1 of the object side surface of the first lens and a radius of curvature R2 of the image side surface of the first lens satisfy: 1.0 < (R1-R2) / (R1+R2) < 1.

5.

9. The optical lens of claim 1, wherein, a maximum field of view FOV of the optical lens, a real image height IH corresponding to the maximum field of view and an object side surface aperture D1 of the first lens satisfy: 0.5 < D1 / IH / tan(FOV / 2) < 1.

0.

10. The optical lens of claim 1, wherein, an optical total length TTL of the optical lens and a sum ∑CT of central thicknesses of the first lens to the eighth lens along the optical axis respectively satisfy: 0.5 < ∑CT / TTL < 0.6.

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