Optical lens

Abstract

The present invention provides an optical lens, which has a total of eight lenses. It is characterized in that, along the optical axis from the object side to the imaging surface, they are in sequence: a first lens with a negative optical power, both its object side and image side are concave surfaces; a second lens with a negative optical power, its object side is a concave surface and its image side is a convex surface; a third lens with a positive optical power, both its object side and image side are convex surfaces; a diaphragm; a fourth lens with a positive optical power, both its object side and image side are convex surfaces; a fifth lens with a positive optical power, both its object side and image side are convex surfaces; a sixth lens with a negative optical power, its object side is a concave surface; a seventh lens with a negative optical power, its object side is a concave surface and its image side is a convex surface; an eighth lens with a positive optical power, its object side is a convex surface and its image side is a concave surface.

Description

Technical Field

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

[0002] With the development of automotive intelligence, the vehicle's assisted driving system has been gradually improved. As one of the main tools for the assisted driving system to obtain external information, the imaging quality of in-vehicle lenses directly affects the performance of the assisted driving system.

[0003] In order to accurately obtain external information, in-vehicle lenses need to be paired with chips with large sizes and high resolutions. Therefore, in-vehicle lenses need to have high resolution capabilities. In addition, for safety considerations, in-vehicle lenses also need to have high stability to adapt to various harsh environments and avoid problems such as a reduction in the imaging performance of in-vehicle lenses when used in different environments. Summary of the Invention

[0004] In view of the above problems, the purpose of the present invention is to provide an optical lens that has the advantages of a large image plane, a large field of view, a large aperture, and miniaturization.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] An optical lens, comprising a total of eight lenses, characterized in that, along the optical axis from the object side to the imaging surface, they are in sequence:

[0007] A first lens with a negative focal power, both its object side and image side being concave surfaces;

[0008] A second lens with a negative focal power, its object side being a concave surface and its image side being a convex surface;

[0009] A third lens with a positive focal power, both its object side and image side being convex surfaces;

[0010] An aperture stop;

[0011] A fourth lens with a positive focal power, both its object side and image side being convex surfaces;

[0012] A fifth lens with a positive focal power, both its object side and image side being convex surfaces;

[0013] A sixth lens with a negative focal power, its object side being a concave surface;

[0014] A seventh lens with a negative focal power, its object side being a concave surface and its image side being a convex surface;

[0015] An eighth lens with a positive focal power, its object side being a convex surface and its image side being a concave surface.

[0016] Preferably, the total optical length TTL of the optical lens and the effective focal length f satisfy: TTL / f < 5.0.

[0017] Preferably, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle satisfy: 1.6 < IH / f.

[0018] Preferably, the back focal length BFL of the optical lens and the effective focal length f satisfy: 0.5 < BFL / f.

[0019] Preferably, the entrance pupil diameter EPD of the optical lens and the true image height IH corresponding to the maximum field of view angle satisfy: 2.7 < IH / EPD < 2.9.

[0020] Preferably, the effective focal length f, the maximum field of view angle FOV, and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.5 < (IH / 2) / (f × Tan(FOV / 2)) < 0.7.

[0021] Preferably, the effective focal length f of the optical lens and the combined focal length f of the first lens to the third lens 13 satisfy: 5.0 < |f 13 / f|.

[0022] Preferably, the effective focal length f of the optical lens and the combined focal length f of the fourth lens to the eighth lens 48 satisfy: 0 < f 48 / f < 2.0.

[0023] Preferably, the maximum field of view angle FOV, the true image height IH corresponding to the maximum field of view angle, and the clear aperture D1 of the object side surface of the first lens of the optical lens satisfy: 0.6 < D1 / IH / Tan(FOV / 2) < 0.8.

[0024] Preferably, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis satisfy: 0.6 < ∑CT / TTL < 0.8.

[0025] Compared with the prior art, the beneficial effects of the present invention are: by reasonably matching the lens shapes and the combination of optical powers between the lenses, the advantages of a large image plane, a large field of view, a large aperture, and miniaturization are achieved simultaneously.

[0026] Additional aspects and advantages of the present invention will be given in part in the following description, and part will become obvious from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings.

[0028] Figure 1 It is a schematic structural diagram of the optical lens according to Embodiment 1 of the present invention.

[0029] Figure 2 It is a field curvature curve graph of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 3 It is an F-Tanθ distortion curve graph of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 4 It is a relative illumination curve graph of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 5 It is an MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0033] Figure 6 It is an axial aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0034] Figure 7 It is a lateral chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0035] Figure 8 It is a schematic structural diagram of the optical lens according to Embodiment 2 of the present invention.

[0036] Figure 9 It is a field curvature curve graph of the optical lens in Embodiment 2 of the present invention.

[0037] Figure 10 It is an F-Tanθ distortion curve graph of the optical lens in Embodiment 2 of the present invention.

[0038] Figure 11 It is a relative illumination curve graph of the optical lens in Embodiment 2 of the present invention.

[0039] Figure 12 It is an MTF curve graph of the optical lens in Embodiment 2 of the present invention.

[0040] Figure 13 It is an axial aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0041] Figure 14 It is a lateral chromatic aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0042] Figure 15 It is a schematic structural diagram of the optical lens according to Embodiment 3 of the present invention.

[0043] Figure 16 It is a field curvature curve graph of the optical lens in Embodiment 3 of the present invention.

[0044] Figure 17 It is the F-Tanθ distortion curve graph of the optical lens in Embodiment 3 of the present invention.

[0045] Figure 18 It is the relative illumination curve graph of the optical lens in Embodiment 3 of the present invention.

[0046] Figure 19 It is the MTF curve graph of the optical lens in Embodiment 3 of the present invention.

[0047] Figure 20 It is the axial aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0048] Figure 21 It is the lateral chromatic aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0049] Figure 22 It is the structural schematic diagram of the optical lens of Embodiment 4 of the present invention.

[0050] Figure 23 It is the field curvature curve graph of the optical lens in Embodiment 4 of the present invention.

[0051] Figure 24 It is the F-Tanθ distortion curve graph of the optical lens in Embodiment 4 of the present invention.

[0052] Figure 25 It is the relative illumination curve graph of the optical lens in Embodiment 4 of the present invention.

[0053] Figure 26 It is the MTF curve graph of the optical lens in Embodiment 4 of the present invention.

[0054] Figure 27 It is the axial aberration curve graph of the optical lens in Embodiment 4 of the present invention.

[0055] Figure 28 It is the lateral chromatic aberration curve graph of the optical lens in Embodiment 4 of the present invention. Detailed implementation manners

[0056] To better understand the present invention, more detailed descriptions will be made on various aspects of the present invention with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present invention and do not limit the scope of the present invention in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0057] It should be noted that in this specification, the expressions such as first, second, third, etc. are only used to distinguish one feature from another, and do not represent any limitation on the features. Therefore, without departing from the teachings of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0058] In the drawings, for the sake of convenience of explanation, the thickness, size and shape of the lens have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0059] In this text, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, 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 defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0060] It should also be understood that the terms "comprising", "comprising of", "having", "containing" and / or "containing of", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when an expression such as "at least one of..." appears after the list of listed features, it modifies the entire list of listed features, rather than individual elements in the list. In addition, when describing the embodiments of the present invention, the use of "may" means "one or more embodiments of the present invention". And the term "exemplary" is intended to refer to an example or illustration.

[0061] Unless otherwise defined, all terms used herein (including technical terms and scientific terms) have the same meaning as the ordinary understanding of those of ordinary skill in the art to which the present invention pertains. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0062] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0063] The optical lens according to an embodiment of the present invention sequentially includes, from the object side to the image side: a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

[0064] In some embodiments, the first lens may have a negative focal power, which is beneficial to reducing the inclination angle of the incident light, thereby effectively sharing the large object-side field of view. Both the object side and the image side of the first lens are concave surfaces, which can reduce the effective working aperture of the first lens and avoid excessive divergence of light, resulting in an overly large aperture for the lenses behind the optical lens.

[0065] In some embodiments, the second lens may have a negative focal power, which can share the negative focal power at the front end of the optical lens, thereby facilitating the avoidance of excessive light deflection caused by overly concentrated focal power of the first lens and reducing the difficulty of chromatic aberration correction for the optical lens. The object side of the second lens is a concave surface, and the image side is a convex surface, which is beneficial to collecting the light incident after passing through the first lens, enabling a smooth transition of the light path and improving the imaging quality of the optical lens.

[0066] In some embodiments, the third lens may have a positive focal power, which is beneficial to converging light while reducing the light deflection angle, allowing for a smooth transition of the light path. Both the object side and the image side of the third lens are convex surfaces, which can reduce the coma generated by the third lens itself and improve the imaging quality of the optical lens.

[0067] In some embodiments, the fourth lens may have a positive focal power, which is beneficial to converging light while reducing the light deflection angle, allowing for a smooth transition of the light path. Both the object side and the image side of the fourth lens are convex surfaces, which can not only reduce the coma generated by the fourth lens itself but also reduce the energy of the ghost image projected onto the image plane due to reflection in the central region, improving the imaging quality of the optical lens.

[0068] In some embodiments, the fifth lens may have a positive focal power, which is beneficial to converging light while reducing the light deflection angle, allowing for a smooth transition of the light path.

[0069] In some embodiments, the sixth lens may have a negative focal power, which is beneficial to correcting the chromatic aberration of the optical lens and improving the imaging quality of the optical lens.

[0070] In some embodiments, the seventh lens may have a negative focal power, which is beneficial to increasing the imaging area of the optical lens and improving the imaging quality of the optical lens. The object side of the seventh lens is a concave surface, and the image side is a convex surface. It can not only converge the marginal light, transmit more light to the rear lenses, improve the relative illumination of the optical lens, but also reduce the field curvature generated by the seventh lens itself, improving the imaging quality of the optical lens.

[0071] In some embodiments, the eighth lens may have a positive optical power, which is beneficial to converging light while reducing the light deflection angle, enabling a smooth transition of the light path. The object side of the eighth lens is convex, and the image side is concave, which can suppress the angle of the marginal field of view incident on the imaging surface and effectively transmit more light beams to the imaging surface, improving the relative illumination of the optical lens.

[0072] In some embodiments, the fifth lens and the sixth lens may be glued together to form a cemented 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, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0073] In some embodiments, a diaphragm for limiting the light beam may be provided between the third lens and the fourth lens. The diaphragm may be disposed near the image side of the third lens, which can reduce the generation of ghost images in the optical lens and is beneficial to converging the light entering the optical system and reducing the rear aperture diameter of the optical lens.

[0074] In some embodiments, the f-number FNO of the optical lens satisfies: FNO ≤ 1.64. Meeting the above range is beneficial to achieving the large-aperture characteristic, and can also ensure the clarity of the image in low-light environments or at night.

[0075] In some embodiments, the maximum field of view FOV of the optical lens satisfies: 100° < FOV. Meeting the above range is beneficial to achieving the wide-angle characteristic, so as to obtain more scene information and meet the requirements of large-range detection.

[0076] In some embodiments, the incident angle CRA of the chief ray of the maximum field of view of the optical lens on the imaging surface satisfies: 10° < CRA < 16°. Meeting the above range can make the allowable error value between the CRA of the optical lens and the CRA of the chip photosensitive element larger, improving the adaptability of the optical lens to the image sensor.

[0077] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f satisfy: TTL / f < 5.0. Meeting the above range can effectively limit the length of the lens and achieve miniaturization of the optical lens.

[0078] In some embodiments, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view satisfy: 1.6 < IH / f. Meeting the above range can enable the optical lens to not only take into account the large-image-plane characteristic but also have good imaging quality.

[0079] In some embodiments, the back focal length (BFL) of the optical lens and the effective focal length (f) satisfy: 0.5 < BFL / f. Meeting the above range is conducive to achieving a balance between obtaining good imaging quality and an optical back focal length that is easy to assemble. While ensuring the imaging quality of the optical lens, it reduces the difficulty of the assembly process of the camera module.

[0080] In some embodiments, the entrance pupil diameter (EPD) of the optical lens and the image height (IH) corresponding to the maximum field of view angle satisfy: 2.7 < IH / EPD < 2.9. Meeting the above range can increase the width of the light beam entering the optical lens, improving the brightness at the image plane of the optical lens and avoiding vignetting.

[0081] In some embodiments, the maximum field of view (FOV) of the optical lens and the angle of incidence (CRA) of the chief ray of the maximum field of view on the image plane satisfy: 3.0 < (FOV / 2) / CRA < 5.0. Meeting the above range allows the optical lens to achieve a large field of view while the incident light can enter the image sensor at an appropriate angle, thereby improving the photosensitivity of the image sensor and the imaging quality of the optical lens.

[0082] In some embodiments, the effective focal length (f), the maximum field of view (FOV), and the image height (IH) corresponding to the maximum field of view of the optical lens satisfy: 0.5 < (IH / 2) / (f × Tan(FOV / 2)) < 0.7. Meeting the above range is conducive to controlling the ideal image height to be close to the actual image height and achieving small distortion.

[0083] In some embodiments, the effective focal length (f) of the optical lens and the focal length (f1) of the first lens satisfy: -1.5 < f1 / f < 0. Meeting the above range can give the first lens an appropriate negative optical power, which is conducive to a relatively gentle change in the refraction angle of the incident light, avoiding excessive aberration caused by too strong a change in refraction, and at the same time helping more light to enter the rear optical system, increasing the illuminance and improving the imaging quality of the optical lens.

[0084] In some embodiments, the effective focal length (f) of the optical lens and the focal length (f2) of the second lens satisfy: -6.0 < f2 / f < 0. Meeting the above range can give the second lens an appropriate negative optical power, which can share the negative optical power at the front end of the optical lens, thereby helping to avoid excessive light deflection caused by too concentrated optical power of the first lens and reducing the difficulty of chromatic aberration correction of the optical lens.

[0085] In some embodiments, the effective focal length (f) of the optical lens and the focal length (f3) of the third lens satisfy: 0 < f3 / f < 1.5. Meeting the above range can give the third lens an appropriate positive optical power, which is conducive to converging light while reducing the light deflection angle, allowing the light to transition smoothly, and improving the imaging quality of the optical lens.

[0086] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0 < f4 / f < 5.0. Meeting the above range can make the fourth lens have an appropriate positive optical power, which is beneficial to converging light while reducing the light deflection angle, enabling the light path to transition smoothly and improving the imaging quality of the optical lens.

[0087] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0 < f5 / f < 1.0. Meeting the above range can make the fifth lens have an appropriate positive optical power, which is beneficial to converging light while reducing the light deflection angle, enabling the light path to transition smoothly and improving the imaging quality of the optical lens.

[0088] 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. Meeting the above range can make the sixth lens have an appropriate negative optical power, which is beneficial to correcting the chromatic aberration of the optical lens and improving the imaging quality of the optical lens.

[0089] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -4.0 < f7 / f < 0. Meeting the above range can make the seventh lens have an appropriate negative optical power, which is beneficial to increasing the imaging area of the optical lens and improving the imaging quality of the optical lens.

[0090] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 0 < f8 / f < 3.0. Meeting the above range can make the eighth lens have an appropriate negative optical power, which is beneficial to converging light while reducing the light deflection angle, enabling the light path to transition smoothly.

[0091] In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the first lens to the third lens 13 satisfy: 5.0 < |f 13 / f|. Meeting the above range, by reasonably distributing the focal lengths of the first lens to the third lens, the light path entering the rear end of the optical lens is smooth, which is beneficial to reducing the correction difficulty of various aberrations and improving the imaging quality of the optical lens.

[0092] In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the fourth lens to the eighth lens 48 satisfy: 0 < f 48 / f < 2.0. Meeting the above range, by reasonably distributing the focal lengths of the fourth lens to the eighth lens, it is beneficial to balance various aberrations and improve the imaging quality of the optical lens.

[0093] In some embodiments, the focal length f5 of the fifth lens and the focal length f6 of the sixth lens of the optical lens satisfy: -0.50 < (f5 + f6) / f < 0. Meeting the above range is beneficial to correcting the chromatic aberration of the optical lens and improving the imaging quality of the optical lens.

[0094] In some embodiments, the maximum field of view FOV, the true image height IH corresponding to the maximum field of view, and the clear aperture D1 of the object side surface of the first lens of the optical lens satisfy: 0.6 < D1 / IH / Tan(FOV / 2) < 0.8. Meeting the above range can have a small front aperture while meeting the requirements of a large field of view and a large image plane for the optical lens, which is beneficial to the miniaturization of the optical lens.

[0095] In some embodiments, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis satisfy: 0.6 < ∑CT / TTL < 0.8. Meeting the above range can effectively compress the total length of the optical lens, and is beneficial to the structural design and production process of the optical lens.

[0096] To enable the system to have better optical performance, multiple aspherical lenses are used in the lens. The surface shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0097] ;

[0098] where z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the conic coefficient, and A, B, C, D, E, F are the surface coefficients of the second order, fourth order, sixth order, eighth order, tenth order, and twelfth order respectively.

[0099] The present invention will be further described below with multiple embodiments. In each embodiment, the thickness, curvature radius, and material selection of each lens in the optical lens are partially different. For specific differences, refer to the parameter tables of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be regarded as equivalent substitution methods and are included in the protection scope of the present invention.

[0100] Embodiment 1

[0101] Please refer to Figure 1 , which shows a schematic structural diagram of the optical lens provided in Embodiment 1 of the present invention. The optical lens sequentially includes, along the optical axis from the object side to the imaging surface: a first lens L1, a second lens L2, a third lens L3, a diaphragm ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1 and a protective glass G2.

[0102] The first lens L1 has a negative focal power, and both its object side S1 and image side S2 are concave surfaces;

[0103] The second lens L2 has a negative focal power, its object side S3 is a concave surface, and its image side S4 is a convex surface;

[0104] The aperture stop ST;

[0105] The third lens L3 has a positive focal power, and both its object side S5 and image side S6 are convex surfaces;

[0106] The fourth lens L4 has a positive focal power, and both its object side S7 and image side S8 are convex surfaces;

[0107] The fifth lens L5 has a positive focal power, and both its object side S9 and image side S10 are convex surfaces;

[0108] The sixth lens L6 has a negative focal power, its object side S11 is a concave surface, and its image side S12 is a convex surface;

[0109] The seventh lens L7 has a negative focal power, its object side S13 is a concave surface, and its image side S14 is a convex surface;

[0110] The eighth lens L8 has a positive focal power, its object side S15 is a convex surface, and its image side S16 is a concave surface;

[0111] The filter G1, both its object side S17 and image side S18 are flat surfaces;

[0112] The protective glass G2, both its object side S19 and image side S20 are flat surfaces;

[0113] The imaging surface S21 is a flat surface;

[0114] The fifth lens L5 and the sixth lens L6 can be cemented to form a cemented lens.

[0115] The relevant parameters of each lens in the optical lens of Example 1 are shown in Table 1-1.

[0116] Table 1-1

[0117]

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

[0119] Table 1-2

[0120]

[0121] Figure 2The field curvature curve of Embodiment 1 is shown, which represents the curvature of light rays with different wavelengths in the meridional image plane and the sagittal image plane. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.09 mm, indicating that the optical lens can correct the field curvature well.

[0122] Figure 3 The F-Tanθ distortion curve of Embodiment 1 is shown, which represents the F-Tanθ distortion of light rays with different wavelengths at different image heights on the imaging plane. The horizontal axis represents the F-Tanθ distortion (unit: %), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the F-Tanθ distortion of the optical lens is controlled within ±40%, indicating that the optical lens can correct the F-Tanθ distortion well.

[0123] Figure 4 The relative illumination curve of Embodiment 1 is shown, which represents the relative illumination values at different field angles on the imaging plane. The horizontal axis represents the semi-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 70% at the maximum semi-field angle, indicating that the optical lens has good relative illumination.

[0124] Figure 5 The modulation transfer function (MTF) curve of Embodiment 1 is shown, which represents the modulation of the lens imaging at different spatial frequencies in each field. 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 this embodiment is above 0.3 within the entire field of view. In the range of 0 - 160 lp / mm, the MTF curve decreases uniformly and smoothly 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.

[0125] Figure 6 The axial aberration curve of 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. It can be seen from the figure that the offset of the axial aberration is controlled within ±20 μm, indicating that the optical lens can correct the axial aberration well.

[0126] Figure 7The vertical chromatic aberration curve diagram of Embodiment 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±3 μm, indicating that the optical lens can excellently correct the chromatic aberration of the edge field and the secondary spectrum of the entire image plane.

[0127] Embodiment 2

[0128] Please refer to Figure 8 , which shows the schematic structural diagram of the optical lens provided in Embodiment 2 of the present invention. The optical lens sequentially includes, along the optical axis from the object side to the imaging plane: a first lens L1, a second lens L2, a third lens L3, a diaphragm ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1 and a protective glass G2.

[0129] The first lens L1 has a negative optical power, and its object side S1 and image side S2 are both concave surfaces;

[0130] The second lens L2 has a negative optical power, its object side S3 is a concave surface, and its image side S4 is a convex surface;

[0131] Diaphragm ST;

[0132] The third lens L3 has a positive optical power, and its object side S5 and image side S6 are both convex surfaces;

[0133] The fourth lens L4 has a positive optical power, and its object side S7 and image side S8 are both convex surfaces;

[0134] The fifth lens L5 has a positive optical power, and its object side S9 and image side S10 are both convex surfaces;

[0135] The sixth lens L6 has a negative optical power, and its object side S11 and image side S12 are both concave surfaces;

[0136] The seventh lens L7 has a negative optical power, its object side S13 is a concave surface, and its image side S14 is a convex surface;

[0137] The eighth lens L8 has a positive optical power, its object side S15 is a convex surface, and its image side S16 is a concave surface;

[0138] Filter G1, its object side S17 and image side S18 are both flat surfaces;

[0139] Protective glass G2, its object side S19 and image side S20 are both flat surfaces;

[0140] The imaging plane S21 is a flat surface;

[0141] The fifth lens L5 and the sixth lens L6 can be cemented to form a cemented lens.

[0142] The relevant parameters of each lens in the optical lens of Embodiment 2 are shown in Table 2-1.

[0143] Table 2-1

[0144]

[0145] The surface shape parameters of the aspherical lenses in the optical lens of Embodiment 2 are shown in Table 2-2.

[0146] Table 2-2

[0147]

[0148] Figure 9 The field curvature curve of Embodiment 2 is shown, which represents the bending degree of light rays of different wavelengths in the meridional image plane and the sagittal image plane. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.08 mm, indicating that the optical lens can correct the field curvature well.

[0149] Figure 10 The F-Tanθ distortion curve of Embodiment 2 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 (unit: %), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the F-Tanθ distortion of the optical lens is controlled within ±40%, indicating that the optical lens can correct the F-Tanθ distortion well.

[0150] Figure 11 The relative illumination curve of Embodiment 2 is shown, which represents the relative illumination values at different field angles on the imaging plane. The horizontal axis represents the semi-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 70% at the maximum semi-field angle, indicating that the optical lens has good relative illumination.

[0151] Figure 12 The modulation transfer function (MTF) curve of Embodiment 2 is shown, which represents the modulation degree of the lens imaging at different spatial frequencies in each field. 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 this embodiment is above 0.3 in the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases uniformly and smoothly from the center to the edge field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0152] Figure 13 The axial aberration curve of Example 2 is shown, which represents the aberration on the optical axis at the imaging plane for 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 offset of the axial aberration is controlled within ±15 μm, indicating that the optical lens can correct the axial aberration well.

[0153] Figure 14 The lateral chromatic aberration curve of Example 2 is shown, which represents the chromatic aberration at different image heights on the imaging plane for each wavelength relative to the central wavelength (0.55 μm). The horizontal axis represents the lateral chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view angle. It can be seen from the figure that the lateral chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±5 μm, indicating that the optical lens can excellently correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0154] Example 3

[0155] Please refer to Figure 15 , which shows the structural schematic diagram of the optical lens provided in Embodiment 3 of the present invention. The optical lens sequentially includes, along the optical axis from the object side to the imaging plane: 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, and a filter G1 and a protective glass G2.

[0156] The first lens L1 has a negative optical power, and its object side S1 and image side S2 are both concave surfaces;

[0157] The second lens L2 has a negative optical power, its object side S3 is a concave surface, and its image side S4 is a convex surface;

[0158] Stop ST;

[0159] The third lens L3 has a positive optical power, and its object side S5 and image side S6 are both convex surfaces;

[0160] The fourth lens L4 has a positive optical power, and its object side S7 and image side S8 are both convex surfaces;

[0161] The fifth lens L5 has a positive optical power, and its object side S9 and image side S10 are both convex surfaces;

[0162] The sixth lens L6 has a negative optical power, and its object side S11 and image side S12 are both concave surfaces;

[0163] The seventh lens L7 has a negative optical power, its object side S13 is a concave surface, and its image side S14 is a convex surface;

[0164] The eighth lens L8 has a positive optical power, its object side S15 is convex, and its image side S16 is concave;

[0165] A filter G1, both its object side S17 and image side S18 are flat;

[0166] A protective glass G2, both its object side S19 and image side S20 are flat;

[0167] The imaging surface S21 is flat;

[0168] The fifth lens L5 and the sixth lens L6 can be cemented to form a cemented lens.

[0169] The relevant parameters of each lens in the optical lens of Embodiment 3 are shown in Table 3-1.

[0170] Table 3-1

[0171]

[0172] The surface type parameters of the aspherical lenses in the optical lens of Embodiment 3 are shown in Table 3-2.

[0173] Table 3-2

[0174]

[0175] Figure 16 The field curvature curve graph of Embodiment 3 is shown, which represents the bending degree of light rays of different wavelengths in the meridional image plane and the sagittal image plane. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.05 mm, indicating that the optical lens can excellently correct the field curvature.

[0176] Figure 17 The F-Tanθ distortion curve graph of Embodiment 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 (unit: %), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the F-Tanθ distortion of the optical lens is controlled within ±40%, indicating that the optical lens can well correct the F-Tanθ distortion.

[0177] Figure 18 The relative illumination curve graph of Embodiment 3 is shown, which represents the relative illumination values at different field angles on the imaging surface. The horizontal axis represents the semi-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 70% at the maximum semi-field angle, indicating that the optical lens has good relative illumination.

[0178] Figure 19The modulation transfer function (MTF) curve of Embodiment 3 is shown, which represents the modulation of lens imaging at different spatial frequencies in 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 this embodiment is above 0.4 within the entire field of view. In the range of 0 - 160 lp / mm, the MTF curve decreases uniformly and smoothly from the central field of view to the edge field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0179] Figure 20 The axial aberration curve of Embodiment 3 is shown, which represents the aberration on the optical axis at the imaging plane for 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 offset of the axial aberration is controlled within ±10 μm, indicating that the optical lens can excellently correct the axial aberration.

[0180] Figure 21 The lateral chromatic aberration curve of Embodiment 3 is shown, which represents the chromatic aberration at different image heights on the imaging plane for each wavelength relative to the central wavelength (0.55 μm). The horizontal axis represents the lateral chromatic aberration value relative to the central wavelength for each wavelength (unit: μm), and the vertical axis represents the normalized field of view angle. It can be seen from the figure that the lateral chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±3 μm, indicating that the optical lens can excellently correct the chromatic aberration in the edge field of view and the secondary spectrum of the entire image plane.

[0181] Embodiment 4

[0182] Please refer to Figure 22 , which shows the schematic structural diagram of the optical lens provided in Embodiment 4 of the present invention. The optical lens sequentially includes, along the optical axis from the object side to the imaging plane: 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, and a filter G1 and a protective glass G2.

[0183] The first lens L1 has a negative optical power, and its object side S1 and image side S2 are both concave surfaces;

[0184] The second lens L2 has a negative optical power, its object side S3 is a concave surface, and its image side S4 is a convex surface;

[0185] Stop ST;

[0186] The third lens L3 has a positive optical power, and its object side S5 and image side S6 are both convex surfaces;

[0187] The fourth lens L4 has a positive optical power, and its object side S7 and image side S8 are both convex surfaces;

[0188] The fifth lens L5 has a positive focal power, and its object side S9 and image side S10 are both convex surfaces;

[0189] The sixth lens L6 has a negative focal power, its object side S11 is a concave surface, and its image side S12 is a convex surface;

[0190] The seventh lens L7 has a negative focal power, its object side S13 is a concave surface, and its image side S14 is a convex surface;

[0191] The eighth lens L8 has a positive focal power, its object side S15 is a convex surface, and its image side S16 is a concave surface;

[0192] The filter G1, its object side S17 and image side S18 are both flat surfaces;

[0193] The protective glass G2, its object side S19 and image side S20 are both flat surfaces;

[0194] The imaging surface S21 is a flat surface;

[0195] The fifth lens L5 and the sixth lens L6 can be glued together to form a cemented lens.

[0196] The relevant parameters of each lens in the optical lens in Embodiment 4 are shown in Table 4-1.

[0197] Table 4-1

[0198]

[0199] The surface shape parameters of the aspherical lenses in the optical lens in Embodiment 4 are shown in Table 4-2.

[0200] Table 4-2

[0201]

[0202] Figure 23 The field curvature curve diagram of Embodiment 4 is shown, which represents the bending degree of light rays with different wavelengths in the meridional image plane and the sagittal image plane. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.04 mm, indicating that the optical lens can correct the field curvature extremely well.

[0203] Figure 24 The F-Tanθ distortion curve diagram of Embodiment 4 is shown, which represents the F-Tanθ distortion of light rays with different wavelengths at different image heights on the imaging surface. The horizontal axis represents the F-Tanθ distortion (unit: %), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the F-Tanθ distortion of the optical lens is controlled within ±40%, indicating that the optical lens can correct the F-Tanθ distortion well.

[0204] Figure 25 The relative illuminance curve graph of Example 4 is shown, which represents the relative illuminance values at different field angles on the imaging surface. The horizontal axis represents the semi-field angle (unit: °), and the vertical axis represents the relative illuminance (unit: %). It can be seen from the figure that the relative illuminance value of the optical lens is still greater than 70% at the maximum semi-field angle, indicating that the optical lens has good relative illuminance.

[0205] Figure 26 The modulation transfer function (MTF) curve graph of Example 4 is shown, which represents the modulation of the lens imaging at different spatial frequencies in each field. 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 this embodiment is above 0.4 within the entire field of view. In the range of 0 - 160 lp / mm, the MTF curve smoothly decreases uniformly from the center to the edge field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0206] Figure 27 The axial aberration curve graph of Example 4 is shown, which represents the aberration on the optical axis at the imaging surface for 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 offset of the axial aberration is controlled within ±10 μm, indicating that the optical lens can well correct the axial aberration.

[0207] Figure 28 The lateral chromatic aberration curve graph of Example 4 is shown, which represents the chromatic aberration at different image heights on the imaging surface for each wavelength relative to the central wavelength (0.55 μm). The horizontal axis represents the lateral chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the lateral chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±4 μm. Please refer to Table 5 for the corresponding optical characteristics of the above embodiments, including the effective focal length f, the overall optical length TTL, the aperture coefficient FNO, the true image height IH, the field of view FOV of the optical lens, and the values corresponding to each conditional formula in the embodiment.

[0208] Table 5

[0209]

[0210] In summary, through the reasonable combination of the lens shapes and the combination of optical powers between the lenses in the optical lens of the embodiment of the present invention, the advantages of large image surface, large field of view, large aperture, and miniaturization are achieved simultaneously.

[0211] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. 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 invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0212] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. An optical lens, comprising eight lenses in total, characterized in that, In order from the object side to the imaging plane along the optical axis: A first lens with negative optical power, both its object side and image side being concave; A second lens with negative optical power, its object side being concave and its image side being convex; A third lens with positive optical power, both its object side and image side being convex; A diaphragm; A fourth lens with positive optical power, both its object side and image side being convex; A fifth lens with positive optical power, both its object side and image side being convex; A sixth lens with negative optical power, its object side being concave; A seventh lens with negative optical power, its object side being concave and its image side being convex; An eighth lens with positive optical power, its object side being convex and its image side being concave.

2. The optical lens according to claim 1, characterized in that, The overall optical length TTL of the optical lens and the effective focal length f satisfy: TTL / f < 5.

0.

3. The optical lens according to claim 1, wherein The effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle satisfy: 1.6 < IH / f.

4. The optical lens according to claim 1, characterized in that, The back focal length BFL of the optical lens and the effective focal length f satisfy: 0.5 < BFL / f.

5. The optical lens according to claim 1, wherein The entrance pupil diameter EPD of the optical lens and the true image height IH corresponding to the maximum field of view angle satisfy: 2.7 < IH / EPD < 2.

9.

6. The optical lens according to claim 1, wherein The effective focal length f, the maximum field of view angle FOV, and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.5 < (IH / 2) / (f×Tan(FOV / 2)) < 0.

7.

7. The optical lens according to claim 1, wherein The effective focal length f of the optical lens and the combined focal length f of the first lens to the third lens 13 satisfy: 5.0 < |f 13 / f|.

8. The optical lens according to claim 1, wherein, The effective focal length f of the optical lens and the combined focal length f of the fourth lens to the eighth lens 48 Satisfy: 0 < f 48 / f < 2.

0.

9. The optical lens according to claim 1, characterized in that, The maximum field of view angle FOV, the true image height IH corresponding to the maximum field of view angle, and the clear aperture D1 of the object side of the first lens of the optical lens satisfy: 0.6 < D1 / IH / Tan(FOV / 2) < 0.

8.

10. The optical lens according to claim 1, characterized in that, The overall optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis respectively satisfy: 0.6 < ∑CT / TTL < 0.8.

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