Optical lens

Abstract

The present invention provides an optical lens, which has a total of six lenses. It is characterized in that, along the optical axis from the object side to the imaging surface, they are successively: a first lens with a negative optical power, whose image side is concave; a second lens with a positive optical power, whose object side is convex and image side is concave; a diaphragm; a third lens with a positive optical power, whose object side and image side are both convex; a fourth lens with a negative optical power, whose object side is concave and image side is convex; a fifth lens with a negative optical power, whose object side is convex and image side is concave; a sixth lens with a positive optical power, whose object side is convex and image side is concave; the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle satisfy: 2.5 < IH / f < 3.0.

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 front-loading of lenses is extending from outside the cabin to inside the cabin. Based on the continuous integration of computer vision, deep learning, and artificial intelligence technologies, the cabin monitoring function is becoming increasingly perfect, evolving from the early driver monitoring system (DMS) to the current occupant monitoring system (OMS). However, existing lenses that meet the requirements of in-vehicle miniaturization have a small field of view and low resolution, and cannot detect the states of drivers and passengers well. Therefore, a lens that not only has a large field of view but also has a high resolution is needed. Summary of the Invention

[0003] Aiming at the above problems, the purpose of the present invention is to propose an optical lens, which has the advantages of a large field of view, a large aperture, low cost, and miniaturization.

[0004] To achieve the above purpose, the technical solution of the present invention is as follows:

[0005] An optical lens, comprising six lenses in total, characterized in that, along the optical axis from the object side to the imaging surface, they are in sequence:

[0006] A first lens with a negative optical power, whose image side is concave;

[0007] A second lens with a positive optical power, whose object side is convex and image side is concave;

[0008] An aperture stop;

[0009] A third lens with a positive optical power, whose object side and image side are both convex;

[0010] A fourth lens with a negative optical power, whose object side is concave and image side is convex;

[0011] A fifth lens with a negative optical power, whose object side is convex and image side is concave;

[0012] A sixth lens with a positive optical power, whose object side is convex and image side is concave;

[0013] For the optical lens, the effective focal length f and the true image height IH corresponding to the maximum field of view angle satisfy: 2.5 < IH / f < 3.0.

[0014] Preferably, the overall optical length TTL of the optical lens and the effective focal length f satisfy: TTL / f < 4.5.

[0015] Preferably, the entrance pupil diameter EPD of the optical lens and the true image height IH corresponding to the maximum field of view satisfy: 6.5 < IH / EPD < 7.5.

[0016] Preferably, the true image height IH corresponding to the maximum field of view of the optical lens and the true image height IH corresponding to the half field of view θ satisfy: 0.4 < IH θ / IH < 0.5.

[0017] Preferably, 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: 0.4 < D1 / IH / Tan(FOV / 2) < 0.6.

[0018] Preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 2.0 < f2 / f < 4.0.

[0019] Preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -4.0 < f5 / f < 0.

[0020] Preferably, the effective focal length f of the optical lens and the combined focal length f of the first lens to the second lens 12 satisfy: -7.0 < f 12 / f < -1.0.

[0021] Preferably, the effective focal length f of the optical lens and the combined focal length f of the third lens to the sixth lens 36 satisfy: 1.0 < f 36 / f < 1.5.

[0022] Preferably, the overall optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis satisfy: 0.4 < ∑CT / TTL < 0.6.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: By reasonably matching the lens shapes and the combination of optical powers between the lenses, the advantages of a large field of view, a large aperture, low cost, and miniaturization are achieved simultaneously.

[0024] The additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, wherein.

[0026] Figure 1Schematic structural diagram of the optical lens according to Embodiment 1 of the present invention.

[0027] Figure 2 Field curvature curve graph of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3 F-Tanθ distortion curve graph of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 4 Relative illumination curve graph of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 5 MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 6 Axial aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 7 Lateral chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0033] Figure 8 Schematic structural diagram of the optical lens according to Embodiment 2 of the present invention.

[0034] Figure 9 Field curvature curve graph of the optical lens in Embodiment 2 of the present invention.

[0035] Figure 10 F-Tanθ distortion curve graph of the optical lens in Embodiment 2 of the present invention.

[0036] Figure 11 Relative illumination curve graph of the optical lens in Embodiment 2 of the present invention.

[0037] Figure 12 MTF curve graph of the optical lens in Embodiment 2 of the present invention.

[0038] Figure 13 Axial aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0039] Figure 14 Lateral chromatic aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0040] Figure 15 Schematic structural diagram of the optical lens according to Embodiment 3 of the present invention.

[0041] Figure 16 Field curvature curve graph of the optical lens in Embodiment 3 of the present invention.

[0042] Figure 17 F-Tanθ distortion curve graph of the optical lens in Embodiment 3 of the present invention.

[0043] Figure 18 This is the relative illuminance curve graph of the optical lens in Embodiment 3 of the present invention.

[0044] Figure 19 This is the MTF curve graph of the optical lens in Embodiment 3 of the present invention.

[0045] Figure 20 This is the axial aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0046] Figure 21 This is the lateral chromatic aberration curve graph of the optical lens in Embodiment 3 of the present invention. Detailed implementation manners

[0047] 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.

[0048] It should be noted that in this specification, the expressions such as first, second, and third are only used to distinguish one feature from another feature 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.

[0049] In the drawings, for the sake of clarity, the thickness, dimensions, and shapes of the lenses 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 for illustration and are not drawn to an exact scale.

[0050] In this document, 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 to be photographed 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.

[0051] It should also be understood that the terms "comprise", "comprising", "have", "including" and / or "containing", when used in this specification, denote the presence of the stated features, elements and / or components, but do not preclude 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 a list of listed features, it modifies the entire list of listed features rather than an individual element in the list. In addition, when describing embodiments of the present invention, the use of "may" means "one or more embodiments of the present invention". Also, the term "exemplary" is intended to refer to an example or illustration.

[0052] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. 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.

[0053] 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.

[0054] 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 diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens and a filter.

[0055] 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 field of view on the object side. The image side surface of the first lens is concave, which can converge the marginal field light and at the same time reduce the deflection angle of the light when passing through the first lens. The first lens may have an aspherical mirror surface, which is beneficial to the large-angle resolution in the edge region of the optical lens and can improve the resolution in the marginal field region.

[0056] In some embodiments, the second lens may have a positive focal power, which is beneficial to converging the light while reducing the deflection angle of the light, making the light trend transition smoothly. The object side surface of the second lens is convex and the image side surface is concave, which can balance the astigmatism generated by the first lens, converge the marginal field light at the same time, make the light trend transition smoothly, and improve the imaging quality of the optical lens.

[0057] In some embodiments, the third lens may have a positive focal power, which is beneficial to converging the light while reducing the deflection angle of the light, making the light trend transition smoothly. Both the object side surface and the image side surface of the third lens are convex, which can reduce the coma generated by the third lens itself and improve the imaging quality of the optical lens.

[0058] In some embodiments, the fourth lens may have a negative optical power, which is beneficial to balancing the spherical aberration generated by the third lens and improving the imaging quality of the optical lens. The object side of the fourth lens is concave, and the image side is convex. It can be glued to the third lens 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.

[0059] In some embodiments, the fifth lens may have a negative optical 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 fifth lens is convex, and the image side is concave, which can balance the spherical aberration, coma and astigmatism generated by the fifth lens itself and improve the imaging quality of the optical lens.

[0060] In some embodiments, the sixth lens may have a positive optical power, which is beneficial to converging light while reducing the light deflection angle and making the light trend transition smoothly. The object side of the sixth 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, effectively transmit more light beams to the imaging surface, and improve the relative illumination of the optical lens; at the same time, it can balance the spherical aberration, coma and astigmatism generated by the fifth lens and improve the imaging quality of the optical lens.

[0061] In some embodiments, a diaphragm for restricting light beams may be provided between the second lens and the third lens. The diaphragm may be disposed near the object side of the third lens, which can reduce the generation of ghost images of the optical lens and is beneficial to converging the light entering the optical system and reducing the rear port diameter of the optical lens.

[0062] In some embodiments, the aperture value FNO of the optical lens satisfies: FNO ≤ 2.50. Meeting the above range is beneficial to achieving the large aperture characteristic, and the image can be ensured to be clear even in low light environments or at night.

[0063] In some embodiments, the maximum field of view FOV of the optical lens satisfies: 120° ≤ FOV. Meeting the above range is beneficial to achieving the wide-angle characteristic, so that more scene information can be obtained to meet the needs of large-range detection.

[0064] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f satisfy: TTL / f < 4.5. Meeting the above range can effectively limit the length of the lens and realize the miniaturization of the optical lens.

[0065] 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 angle satisfy: 2.5 < IH / f < 3.0. Meeting the above range can enable the optical lens to not only take into account the characteristics of a large image plane but also have good imaging quality.

[0066] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f satisfy: 0.8 < 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 assembly process difficulty of the camera module.

[0067] In some embodiments, the entrance pupil diameter EPD of the optical lens and the true image height IH corresponding to the maximum field of view angle satisfy: 6.5 < IH / EPD < 7.5. 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.

[0068] In some embodiments, the true image height IH corresponding to the maximum field of view angle and the true image height IH corresponding to the half field of view angle θ satisfy: 0.4 < IH θ / IH < 0.5. Meeting the above range can increase the proportion of the imaging range of the edge field of view in the entire imaging range. The larger the imaging range, the more pixels occupied on the corresponding chip surface, and thus more detailed information can be obtained.

[0069] In some embodiments, 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: 0.75 < (IH / 2) / (f × Tan(FOV / 2)) < 0.85. Meeting the above range is conducive to controlling the ideal image height to be close to the actual image height and achieving small distortion.

[0070] In some embodiments, 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 satisfy: 0.4 < D1 / IH / Tan(FOV / 2) < 0.6. Meeting the above range can have a small front aperture while meeting the requirements of a large field of view angle and a large image plane for the optical lens, which is conducive to the miniaturization of the optical lens.

[0071] 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 refraction change, and at the same time helping more light enter the rear optical system, increasing the illuminance and improving the imaging quality of the optical lens.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 2.0 < f2 / f < 4.0. Satisfying the above range can endow the second lens with an appropriate positive optical power, which can balance the astigmatism generated by the first lens, converge the marginal field light rays at the same time, make the light ray trend transition smoothly, and improve the imaging quality of the optical lens.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0 < f3 / f < 0.8. Satisfying the above range can endow the third lens with an appropriate positive optical power, which is beneficial to converging light rays while reducing the light ray deflection angle, making the light ray trend transition smoothly, and improving the imaging quality of the optical lens.

[0074] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -1.5 < f4 / f < 0. Satisfying the above range can endow the fourth lens with an appropriate negative optical power, which is beneficial to balancing the spherical aberration generated by the third lens and improving the imaging quality of the optical lens.

[0075] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -4.0 < f5 / f < 0. Satisfying the above range can endow the fifth lens with 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.

[0076] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0 < f6 / f < 2.0. Satisfying the above range can endow the sixth lens with an appropriate positive optical power, which is beneficial to converging light rays while reducing the light ray deflection angle, making the light ray trend transition smoothly.

[0077] In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the first lens to the second lens 12 satisfy: -7.0 < f 12 / f < -1.0. Satisfying the above range, by reasonably distributing the focal lengths of the first lens to the second lens, the light ray trend entering the rear end of the optical lens is made smooth, which is beneficial to reducing the correction difficulty of various aberrations and improving the imaging quality of the optical lens.

[0078] In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the third lens to the sixth lens 36 satisfy: 1.0 < f 36 / f < 1.5. Satisfying the above range, by reasonably distributing the focal lengths of the third lens to the sixth lens, it is beneficial to balance various aberrations and improve the imaging quality of the optical lens.

[0079] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: -1.0 < R5 / R8 < 0. Satisfying the above range can reduce various aberrations of the cemented lens formed by the mutual cementing of the third lens and the fourth lens, and improve the imaging quality of the optical lens.

[0080] 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 sixth lens along the optical axis satisfy: 0.4 < ∑CT / TTL < 0.6. Satisfying 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.

[0081] To enable the system to have better optical performance, multiple aspherical lenses are used in the lens. The shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0082] ;

[0083] where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the conic coefficient, and A, B, C, D, E, F are the second-order, fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients respectively.

[0084] The present invention will be further described below with multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are partially different. For specific differences, please refer to the parameter tables of each embodiment. The following embodiments are only the 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.

[0085] Embodiment 1

[0086] 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 diaphragm ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a filter G1.

[0087] The first lens L1 has a negative optical power, and its object side surface S1 and image side surface S2 are both concave surfaces;

[0088] The second lens L2 has a positive optical power, its object side surface S3 is a convex surface, and its image side surface S4 is a concave surface;

[0089] Diaphragm ST;

[0090] The third lens L3 has a positive focal power, and its object side S5 and image side S6 are both convex surfaces;

[0091] The fourth lens L4 has a negative focal power, its object side S7 is a concave surface, and its image side S8 is a convex surface;

[0092] The fifth lens L5 has a negative focal power, its object side S9 is a convex surface, and its image side S10 is a concave surface;

[0093] The sixth lens L6 has a positive focal power, its object side S11 is a convex surface, and its image side S12 is a concave surface;

[0094] The filter G1, its object side S13 and image side S14 are both flat surfaces;

[0095] The imaging surface S15 is a flat surface;

[0096] The third lens L3 and the fourth lens L4 can be cemented to form a cemented lens.

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

[0098] Table 1-1

[0099]

[0100] The surface type parameters of the aspherical lenses in the optical lens of Embodiment 1 are shown in Table 1-2.

[0101] Table 1-2

[0102]

[0103] Figure 2 The field curvature curve graph of Embodiment 1 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.

[0104] Figure 3 The F-Tanθ distortion curve graph of Embodiment 1 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 ±22%, indicating that the optical lens can better correct the F-Tanθ distortion.

[0105] Figure 4The relative illuminance curve of Embodiment 1 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 60% at the maximum semi-field angle, indicating that the optical lens has good relative illuminance.

[0106] 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 0.4 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 field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0107] Figure 6 The axial aberration curve of Embodiment 1 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 correct the axial aberration extremely well.

[0108] Figure 7 The lateral chromatic aberration curve of Embodiment 1 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 between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens can correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane extremely well.

[0109] Embodiment 2

[0110] Please refer to Figure 8 , which shows the structural schematic 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 surface: a first lens L1, a second lens L2, a stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a filter G1.

[0111] The first lens L1 has a negative focal power, and its object side surface S1 and image side surface S2 are both concave surfaces;

[0112] The second lens L2 has a positive focal power, its object side surface S3 is a convex surface, and its image side surface S4 is a concave surface;

[0113] Stop ST;

[0114] The third lens L3 has a positive focal power, and its object side S5 and image side S6 are both convex surfaces;

[0115] The fourth lens L4 has a negative focal power, its object side S7 is a concave surface, and its image side S8 is a convex surface;

[0116] The fifth lens L5 has a negative focal power, its object side S9 is a convex surface, and its image side S10 is a concave surface;

[0117] The sixth lens L6 has a positive focal power, its object side S11 is a convex surface, and its image side S12 is a concave surface;

[0118] The filter G1, its object side S13 and image side S14 are both flat surfaces;

[0119] The imaging surface S15 is a flat surface;

[0120] The third lens L3 and the fourth lens L4 can be cemented to form a cemented lens.

[0121] The relevant parameters of each lens in the optical lens of Embodiment 2 are shown in Table 2-1.

[0122] Table 2-1

[0123]

[0124] The surface shape parameters of the aspherical lenses in the optical lens of Embodiment 2 are shown in Table 2-2.

[0125] Table 2-2

[0126]

[0127] Figure 9 The field curvature curve graph 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 excellently correct the field curvature.

[0128] Figure 10 The F-Tanθ distortion curve graph of Embodiment 2 is shown, which represents the F-Tanθ distortion of light rays of different wavelengths at different image heights on the imaging surface. The horizontal axis represents the F-Tanθ distortion (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 ±22%, indicating that the optical lens can better correct the F-Tanθ distortion.

[0129] Figure 11The relative illuminance curve of Embodiment 2 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 at the maximum semi-field angle is still greater than 60%, indicating that the optical lens has good relative illuminance.

[0130] Figure 12 The modulation transfer function (MTF) curve of Embodiment 2 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 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.

[0131] Figure 13 The axial aberration curve of Embodiment 2 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 ±20 μm, indicating that the optical lens can correct the axial aberration well.

[0132] Figure 14 The lateral chromatic aberration curve of Embodiment 2 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 between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens can correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane extremely well.

[0133] Embodiment 3

[0134] 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 surface: a first lens L1, a second lens L2, a diaphragm ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a filter G1.

[0135] The first lens L1 has a negative optical power. Its object side surface S1 is convex, and its image side surface S2 is concave;

[0136] The second lens L2 has a positive optical power. Its object side surface S3 is convex, and its image side surface S4 is concave;

[0137] Diaphragm ST;

[0138] The third lens L3 has a positive optical power, and its object side S5 and image side S6 are both convex surfaces;

[0139] The fourth lens L4 has a negative optical power, its object side S7 is a concave surface, and its image side S8 is a convex surface;

[0140] The fifth lens L5 has a negative optical power, its object side S9 is a convex surface, and its image side S10 is a concave surface;

[0141] The sixth lens L6 has a positive optical power, its object side S11 is a convex surface, and its image side S12 is a concave surface;

[0142] The filter G1, its object side S13 and image side S14 are both flat surfaces;

[0143] The imaging surface S15 is a flat surface;

[0144] The third lens L3 and the fourth lens L4 can be cemented to form a cemented lens.

[0145] The relevant parameters of each lens in the optical lens of Embodiment 3 are shown in Table 3-1.

[0146] Table 3-1

[0147]

[0148] The surface shape parameters of the aspherical lenses in the optical lens of Embodiment 3 are shown in Table 3-2.

[0149] Table 3-2

[0150]

[0151] 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 ±0.08 mm, indicating that the optical lens can excellently correct the field curvature.

[0152] 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 ±18%, indicating that the optical lens can better correct the F-Tanθ distortion.

[0153] Figure 18The relative illuminance curve of Embodiment 3 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 60% at the maximum semi-field angle, indicating that the optical lens has good relative illuminance.

[0154] Figure 19 The modulation transfer function (MTF) curve of Embodiment 3 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 field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0155] Figure 20 The axial aberration curve of Embodiment 3 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 ±20 μm, indicating that the optical lens can correct the axial aberration well.

[0156] Figure 21 The lateral chromatic aberration curve of Embodiment 3 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 ±2 μm, indicating that the optical lens can correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane extremely well.

[0157] Please refer to Table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total optical length TTL, the f-number 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.

[0158] Table 4

[0159]

[0160] In summary, the optical lens of the embodiment of the present invention realizes the advantages of large field of view, large aperture, low cost, and miniaturization by reasonably matching the lens shapes and the combination of optical powers between the lenses.

[0161] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc., mean 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.

[0162] The above-described embodiments only express several implementation manners of the present invention. The descriptions are relatively specific and detailed, but 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 should be subject to the appended claims.

Claims

1. An optical lens, consisting of six lenses in total, characterized in that, From the object side to the imaging plane along the optical axis, they are in sequence as follows: A first lens with negative optical power, whose image side is concave; A second lens with positive optical power, whose object side is convex and image side is concave; A diaphragm; A third lens with positive optical power, whose object side and image side are both convex; A fourth lens with negative optical power, whose object side is concave and image side is convex; A fifth lens with negative optical power, whose object side is convex and image side is concave; A sixth lens with positive optical power, whose object side is convex and image side is concave; For the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle, the following is satisfied: 2.5 < IH / f < 3.

0.

2. The optical lens according to claim 1, characterized in that For the overall optical length TTL of the optical lens and the effective focal length f, the following is satisfied: TTL / f < 4.

5.

3. The optical lens according to claim 1, characterized in that, For the entrance pupil diameter EPD of the optical lens and the true image height IH corresponding to the maximum field of view angle, the following is satisfied: 6.5 < IH / EPD < 7.

5.

4. The optical lens according to claim 1, wherein The true image height IH corresponding to the maximum field of view angle of the optical lens and the true image height IH corresponding to the half field of view angle θ Satisfy: 0.4 < IH θ / IH < 0.

5.

5. The optical lens according to claim 1, characterized in that, For 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, the following is satisfied: 0.4 < D1 / IH / Tan(FOV / 2) < 0.

6.

6. The optical lens according to claim 1, characterized in that For the effective focal length f of the optical lens and the focal length f2 of the second lens, the following is satisfied: 2.0 < f2 / f < 4.

0.

7. The optical lens according to claim 1, wherein For the effective focal length f of the optical lens and the focal length f5 of the fifth lens, the following is satisfied: -4.0 < f5 / f < 0.

8. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the combined focal length f of the first lens to the second lens 12 Satisfy: -7.0 < f 12 / f < -1.

0.

9. 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 third lens to the sixth lens 36 satisfy: 1.0 < f 36 / f < 1.

5.

10. The optical lens according to claim 1, characterized in that, For the overall optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis respectively, the following is satisfied: 0.4 < ∑CT / TTL < 0.6.

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