Optical lens

Abstract

The invention provides an optical lens, which comprises six lenses which sequentially comprise a first lens with negative focal power, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with negative focal power from an object side to an image side along an optical axis, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a convex surface; the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a convex surface; and the sixth lens has positive focal power, and the object side surface of the sixth lens is a convex surface. According to the optical lens provided by the invention, the imaging quality of the optical lens can be improved, the aberration can be reduced, the imaging quality of the optical lens can be improved, and the lens has one or more advantages of miniaturization, large target surface, large aperture, large field angle, high imaging quality and the like.

Description

Technical Field

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

[0002] With the continuous improvement of people's requirements for driving experience, on-vehicle application optical lenses are increasingly used in intelligent driving, and the status of on-vehicle optical lenses in the automotive-related industry is constantly rising.

[0003] An electronic rearview mirror is an indirect vision device that obtains a specified field of view through a system composed of a camera and a monitor. It includes electronic devices such as a high-definition camera, a digital vision processing system, a safety system, and a liquid crystal display, and is a new type of rearview mirror that can replace traditional rearview mirrors. Electronic rearview mirrors are generally designed with a main lens and a wide-angle lens, and present images through a display screen, which can provide a wider field of view, eliminate blind spots, help drivers better understand the surrounding environment, and reduce the occurrence of accidents. In addition to requiring the lens to have a thin, light, short, and small shape and high pixel and high resolution characteristics, the existing electronic rearview mirror lenses also require the optical lens to be able to clearly image under low illuminance conditions. Therefore, it is necessary to develop an optical lens with good imaging effects. Summary of the Invention

[0004] Aiming at the above problems, the purpose of the present invention is to provide an optical lens with excellent imaging quality.

[0005] The technical solution adopted by the present invention is as follows: An optical lens, comprising a total of six lenses, which in sequence from the object side to the imaging surface along the optical axis include: A first lens with negative optical power, the object side surface of which is concave and the image side surface of which is concave; A second lens with positive optical power, the object side surface of which is convex and the image side surface of which is concave; A third lens with positive optical power, the object side surface of which is convex and the image side surface of which is convex; A fourth lens with positive optical power, the object side surface of which is concave and the image side surface of which is convex; A fifth lens with negative optical power, the object side surface of which is concave and the image side surface of which is convex; A sixth lens with positive optical power, the object side surface of which is convex; Wherein, the curvature radius R3 of the object side surface of the second lens and the curvature radius R4 of the image side surface of the second lens satisfy: -0.9 < (R3 - R4) / (R3 + R4) < -0.1; The curvature radius R9 of the object side surface of the fifth lens and the curvature radius R10 of the image side surface of the fifth lens satisfy: -1 < (R9 - R10) / (R9 + R10) < -0.2.

[0006] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.3 < TTL / f < 3.1; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 1.5 < TTL / IH < 2.4.

[0007] Further preferably, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1.7 < IH / EPD < 3.2; the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1 < IH / f < 1.8.

[0008] Further preferably, the half clear aperture d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field of view angle of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 0.77 < d1 / (IH / 2) / tan(FOV / 2) < 1.67; the optical lens further includes a diaphragm, the diaphragm is located between the third lens and the fourth lens or between the second lens and the third lens, and the combined focal length ffront of the lenses located in front of the diaphragm and the combined focal length frear of the lenses located behind the diaphragm satisfy: 0 < ffront / frear < 4.2.

[0009] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.8 < f1 / f < -0.9; the curvature radius R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -3.5 < R1 / f < -1.1; the curvature radius R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: 1.1 < R2 / f < 3.4.

[0010] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.3 < f2 / f < 25; the curvature radius R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: 0.7 < R3 / f < 5; the curvature radius R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: 2.7 < R4 / f < 11.

[0011] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.7 < f3 / f < 1; the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.6 < f6 / f < 25.

[0012] More preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 3 < f4 / f < 35; the object-side curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: -15 < R7 / f < -3.2; the image-side curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -3.4 < R8 / f < -1.3.

[0013] More preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.7 < f5 / f < -0.6; the object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: -0.65 < R9 / f < -0.1; the image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -12 < R10 / f < -0.3.

[0014] More preferably, the object-side curvature radius R7 of the fourth lens and the image-side curvature radius R8 of the fourth lens satisfy: 0 < (R7 - R8) / (R7 + R8) < 0.8; the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: -0.1 < (R1 + R2) / (R1 - R2) < 0.4.

[0015] The optical lens provided by the present invention adopts six lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberration, improve the imaging quality of the optical lens, and make the lens have one or more advantages such as miniaturization, large target surface, large aperture, large field of view angle, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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, where: Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0017] Figure 2 is a F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 3 is a MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0019] Figure 4 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0020] Figure 5 is a F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 2 of the present invention.

[0021] Figure 6 This is the MTF curve graph of the optical lens in Embodiment 2 of the present invention.

[0022] Figure 7 This is the structural schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0023] Figure 8 This is the F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 3 of the present invention.

[0024] Figure 9 This is the MTF curve graph of the optical lens in Embodiment 3 of the present invention.

[0025] Figure 10 This is the structural schematic diagram of the optical lens in Embodiment 4 of the present invention.

[0026] Figure 11 This is the F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 4 of the present invention.

[0027] Figure 12 This is the MTF curve graph of the optical lens in Embodiment 4 of the present invention.

[0028] Figure 13 This is the structural schematic diagram of the optical lens in Embodiment 5 of the present invention.

[0029] Figure 14 This is the F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 5 of the present invention.

[0030] Figure 15 This is the MTF curve graph of the optical lens in Embodiment 5 of the present invention.

[0031] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0032] To better understand the present application, more detailed descriptions of various aspects of the present application will be made with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application and do not limit the scope of the present application 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.

[0033] 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 feature and do not represent any limitation on the feature. 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.

[0034] In the drawings, for ease of explanation, the thickness, dimensions, and shape of the lens are slightly exaggerated. Specifically, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the spherical or aspherical shape is not limited to the spherical or aspherical shape shown in the drawings. The drawings are for illustrative purposes only and are not drawn to an exact scale.

[0035] 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.

[0036] It should also be understood that the terms "comprising", "including", "having", "containing", and / or "including" 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. Further, 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 individual elements in the list. Further, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application". And the term "exemplary" is intended to refer to an example or illustration.

[0037] 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 application 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.

[0038] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will detail this application with reference to the drawings and in conjunction with the embodiments.

[0039] The optical lens provided by the embodiment of the present invention has a total of six lenses, which are, in order from the object side to the imaging surface along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens.

[0040] In some embodiments, the first lens may have a negative focal power, with its object side being concave and its image side being concave. The second lens may have a positive focal power, with its object side being convex and its image side being concave. The third lens may have a positive focal power, with its object side being convex and its image side being convex. The fourth lens may have a positive focal power, with its object side being concave and its image side being convex. The fifth lens may have a negative focal power, with its object side being concave and its image side being convex. The sixth lens may have a positive focal power, with its object side being convex and its image side being either concave or convex.

[0041] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the third lens and the fourth lens or between the second lens and the third lens. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the imaging. When the diaphragm is located between the third lens and the fourth lens or between the second lens and the third lens, it is convenient for the correction of diaphragm aberration.

[0042] In some embodiments, the optical lens may further include a filter, and the filter is disposed between the sixth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0043] In some embodiments, the radius of curvature R3 of the object side of the second lens and the radius of curvature R4 of the image side of the second lens satisfy: -0.9 < (R3 - R4) / (R3 + R4) < -0.1. Satisfying the above range, by controlling the second lens to have a suitable surface shape, it is beneficial to strengthen the correction of higher-order aberrations and reduce the attenuation degree of the relative illumination of the optical lens. At the same time, the second lens adopts a meniscus shape, which is beneficial to correcting the distortion of the optical lens. More specifically, -0.87 < (R3 - R4) / (R3 + R4) < -0.14.

[0044] In some embodiments, the radius of curvature R9 of the object side of the fifth lens and the radius of curvature R10 of the image side of the fifth lens satisfy: -1 < (R9 - R10) / (R9 + R10) < -0.2. Satisfying the above range, reasonably controlling the surface shape of the fifth lens helps to further optimize distortion and field curvature and reduce the difficulty of correcting higher-order aberrations of subsequent lenses. More specifically, -0.91 < (R9 - R10) / (R9 + R10) < -0.3.

[0045] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.3 < TTL / f < 3.1. Satisfying the above range can effectively limit the length of the lens and is beneficial to realizing the miniaturization of the optical lens. More specifically, 2.53 < TTL / f < 3.04.

[0046] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 1.5 < TTL / IH < 2.4. Meeting the above range ensures that, with the same total length of the lens, a larger image plane can be obtained, enabling a larger-sized imaging chip to be matched to achieve high-definition imaging, and better achieving the balance between the small total length and the large image plane of the lens. More specifically, 1.59 < TTL / IH < 2.27.

[0047] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1.7 < IH / EPD < 3.2. Meeting the above range is beneficial to increasing the light passing amount, making the peripheral field of view and the central field of view brighter and more uniform. More specifically, 1.84 < IH / EPD < 2.97.

[0048] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1 < IH / f < 1.8. Meeting the above range controls the image height and focal length of the optical lens within a reasonable range, which helps the optical lens to have the characteristic of a large image plane and improve the imaging quality. More specifically, 1.11 < IH / f < 1.66.

[0049] In some embodiments, the half-aperture d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.77 < d1 / (IH / 2) / tan(FOV / 2) < 1.67. Meeting the above range can have a small front aperture while meeting the requirements of the optical lens having a large field of view angle and a large image plane.

[0050] In some embodiments, the combined focal length f_front of the lenses located in front of the aperture and the effective focal length f of the optical lens satisfy: 0.8 < f_front / f < 7; the combined focal length f_back of the lenses located behind the aperture and the effective focal length f of the optical lens satisfy: 1 < f_back / f < 20; the combined focal length f_front of the lenses located in front of the aperture and the combined focal length f_back of the lenses located behind the aperture satisfy: 0 < f_front / f_back < 4.2. Meeting the above range is beneficial to balancing various aberrations of the system and improving the overall imaging quality by reasonably setting the focal lengths of the lens groups before and after the aperture. More specifically, 0.86 < f_front / f < 6.62; 1.1 < f_back / f < 19.87; 0.03 < f_front / f_back < 4.02.

[0051] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.8 < f1 / f < -0.9; the radius of curvature R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -3.5 < R1 / f < -1.1; the radius of curvature R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: 1.1 < R2 / f < 3.4; the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R2 of the image side surface of the first lens satisfy: -0.1 < (R1 + R2) / (R1 - R2) < 0.4. Satisfying the above ranges, by setting the first lens to have a negative refractive power and a suitable surface shape, it is beneficial for the first lens to receive light at a larger angle and collect as much light as possible to enter the rear optical system, increasing the light flux while achieving a large field of view. More specifically, -2.63 < f1 / f < -0.91; -3.32 < R1 / f < -1.24; 1.16 < R2 / f < 3.12; -0.03 < (R1 + R2) / (R1 - R2) < 0.36.

[0052] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.3 < f2 / f < 25; the radius of curvature R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: 0.7 < R3 / f < 5; the radius of curvature R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: 2.7 < R4 / f < 11. Satisfying the above ranges, it is defined that the second lens has an appropriate positive optical power and a suitable surface shape, which has the effect of converging light, enabling the diverging light to smoothly enter the rear optical system, reducing the height of the peripheral light, and being beneficial for reducing the aperture of the rear lens. More specifically, 1.47 < f2 / f < 24.24; 0.74 < R3 / f < 4.7; 2.92 < R4 / f < 10.09.

[0053] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.7 < f3 / f < 1; the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -0.4 < (R5 + R6) / (R5 - R6) < 0.3. Satisfying the above ranges, it is defined that the third lens has an appropriate positive optical power and a suitable surface shape, which is beneficial for the convergence of light, can effectively correct the distortion of the edge field of view, reduce the degree of deformation of the edge of the captured image, and improve the image quality. More specifically, 0.77 < f3 / f < 0.93; -0.38 < (R5 + R6) / (R5 - R6) < 0.22.

[0054] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.6 < f6 / f < 25. Meeting the above range and defining that the sixth lens has a positive optical power is beneficial to light convergence, enabling the light path to smoothly transition to the rear, reducing the height of the light incident on the rear, slowing down the upward trend of the light, avoiding light energy loss caused by too large a chief ray angle between the large field-of-view light and the imaging surface when reaching the imaging surface, facilitating the improvement of the illuminance of the edge field of view, and being conducive to achieving a short overall optical length. More specifically, 0.67 < f6 / f < 23.46.

[0055] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 3 < f4 / f < 35; the radius of curvature R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -15 < R7 / f < -3.2; the radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -3.4 < R8 / f < -1.3; the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 0 < (R7 - R8) / (R7 + R8) < 0.8. Meeting the above range is beneficial to the convergence of light, sharing the positive optical power of the second lens and the third lens, avoiding excessive light deflection, and better achieving high-quality imaging of the lens. More specifically, 3.22 < f4 / f < 33.44; -14.65 < R7 / f < -3.49; -3.1 < R8 / f < -1.45; 0.05 < (R7 - R8) / (R7 + R8) < 0.73.

[0056] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.7 < f5 / f < -0.6; the radius of curvature R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -0.65 < R9 / f < -0.1; the radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -12 < R10 / f < -0.3. Meeting the above range makes the light in the edge field of view show an upward trend, which is beneficial to the image point on the imaging surface moving away from the optical axis, so as to be conducive to achieving the effect of matching with a large chip, obtaining a larger picture, effectively eliminating aberration, and improving the resolution ability of the optical lens. More specifically, -1.56 < f5 / f < -0.69; -0.61 < R9 / f < -0.15; -11.62 < R10 / f < -0.31.

[0057] In some embodiments, the effective focal length f of the optical lens, the true image height IH corresponding to the maximum field-of-view angle of the optical lens, and the maximum field-of-view angle FOV of the optical lens satisfy: 0.8 < (IH / 2) / (f × Tan(FOV / 2)) < 1.13. Meeting the above range controls the distortion of the optical lens within a reasonable range.

[0058] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.24 < BFL / f < 0.5. Meeting the above range limits the optical lens to have an appropriate back focus, facilitating the reasonable arrangement of the positions of each lens and reducing the processing and assembly difficulty at the same time.

[0059] In some embodiments, 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: 0.57 < ∑CT / TTL < 0.73. Meeting the above range and reasonably configuring the overall optical length of the optical lens and the sum of the thicknesses of each lens helps to achieve high-pixel characteristics and improve the imaging quality of the optical lens.

[0060] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis and the effective focal length f of the optical lens satisfy: 1.51 < ΣCT / f < 2.2. Meeting the above range can effectively correct the field curvature and distortion of the optical lens and improve the imaging quality of the optical lens.

[0061] In some embodiments, the optical lens satisfies the following conditional expressions: 4 mm < f < 5.5 mm; 2.3 mm < EPD < 3.2 mm; 11 mm < TTL < 14 mm; 1.6 < Fno < 2; 15° < CRA < 32°; 1 mm < BFL < 2.6 mm; 55° < FOV < 80°; 5.5 mm < IH < 7.5 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the overall optical length of the optical lens, Fno represents the aperture value of the optical lens, CRA represents the chief ray angle of incidence of the optical lens, BFL represents the back focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, and IH represents the true image height corresponding to the maximum field of view angle of the optical lens. Meeting the above range, the optical lens has at least one or more advantages such as miniaturization, large target surface, large aperture, and large field of view angle. More specifically, 4.12 mm < f < 5.13 mm; 2.25 mm < EPD < 3.11 mm; 11.77 mm < TTL < 13.01 mm; 1.64 < Fno < 1.96; 16.13° < CRA < 31.42°; 1.14 mm < BFL < 2.49 mm; 59° < FOV < 76°; 5.71 mm < IH < 7.39 mm.

[0062] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. In the optical lens provided by the present invention, the first lens and the third lens are made of glass lenses, and the second lens, the fourth lens, the fifth lens, and the sixth lens are made of plastic lenses; adopting a glass-plastic hybrid structure can effectively reduce costs, correct aberrations, reduce the volume, and provide an optical lens product with higher cost performance.

[0063] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the first lens and the third lens of the present invention adopt spherical lenses; the second lens, the fourth lens, the fifth lens, and the sixth lens adopt aspherical lenses.

[0064] In each embodiment of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equation: ; 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 B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients, respectively.

[0065] The present invention will be further described in multiple embodiments below. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are somewhat 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 other changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0066] Embodiment 1 Please refer to Figure 1 , which shows a schematic structural diagram of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 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, and a filter G1.

[0067] Among them, the first lens L1 has a negative optical power, its object side S1 is concave, and its image side S2 is concave; The second lens L2 has a positive optical power, its object side S3 is convex, and its image side S4 is concave; The third lens L3 has a positive optical power, its object side S5 is convex, and its image side S6 is convex; The fourth lens L4 has a positive optical power, its object side S7 is concave, and its image side S8 is convex; The fifth lens L5 has a negative optical power, its object side S9 is concave, and its image side S10 is convex; The sixth lens L6 has a positive optical power, its object side S11 is convex, and its image side S12 is convex; Both the object side S13 and the image side S14 of the filter G1 are flat; The imaging surface S15 is flat.

[0068] The first lens L1 and the third lens L3 are made of glass spherical lenses, and the second lens L2, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are made of plastic aspherical lenses.

[0069] The relevant parameters of each lens in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0070] Table 1-1 The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0071] Table 1-2 In this embodiment, the F-Tan(Theta) distortion curve graph and the MTF curve graph of the optical lens 100 are respectively as Figure 2 、 Figure 3 shown.

[0072] Figure 2 The F-Tan(Theta) distortion curve of Embodiment 1 is shown, which represents the distortion of light rays with different wavelengths at different image heights on the imaging surface. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the distortion of the optical lens is controlled within 0-13%, indicating that the optical lens 100 can well correct the distortion.

[0073] Figure 3The MTF (Modulation Transfer Function) curve graph of Embodiment 1 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 to 120 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.

[0074] Embodiment 2 Please refer to Figure 4 , which shows the structural schematic diagram of the optical lens 200 provided in Embodiment 2 of the present invention. Compared with Embodiment 1, the main difference is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0075] The relevant parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0076] Table 2-1 The surface type parameters of the aspherical lenses in the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0077] Table 2-2 In this embodiment, the F-Tan(Theta) distortion curve graph and the MTF curve graph of the optical lens 200 are respectively as Figure 5 , Figure 6 shown.

[0078] From Figure 5 it can be seen that the distortion of the optical lens is controlled within 0 to 13%, indicating that the optical lens 200 can well correct the distortion.

[0079] From Figure 6 it can be seen that the MTF value of this embodiment is above 0.48 within the entire field of view. In the range of 0 to 120 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.

[0080] Embodiment 3 Please refer to Figure 7 , which shows the structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present invention. Compared with Embodiment 1, the main difference is that the image side surface S12 of the sixth lens L6 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0081] The relevant parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0082] Table 3-1 The aspheric lens surface parameters of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0083] Table 3-2 In this embodiment, the F-Tan(Theta) distortion curve graph and MTF curve graph of the optical lens 300 are respectively as Figure 8 , Figure 9 shown.

[0084] From Figure 8 it can be seen that the distortion of the optical lens is controlled within -4% to 0, indicating that the optical lens 300 can correct distortion well.

[0085] From Figure 9 it can be seen that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve smoothly decreases uniformly 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.

[0086] Embodiment 4 Please refer to Figure 10 , which shows the structural schematic diagram of the optical lens 400 provided in Embodiment 4 of the present invention. Compared with Embodiment 1, the main differences are: the image side S12 of the sixth lens L6 is a concave surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0087] The relevant parameters of each lens in the optical lens 400 in Embodiment 4 are shown in Table 4-1.

[0088] Table 4-1 The aspheric lens surface parameters of the optical lens 400 in Embodiment 4 are shown in Table 4-2.

[0089] Table 4-2 In this embodiment, the F-Tan(Theta) distortion curve graph and MTF curve graph of the optical lens 400 are respectively as Figure 11 , Figure 12 shown.

[0090] From Figure 11It can be seen that the distortion of the optical lens is controlled within 0-8%, indicating that the optical lens 400 can correct the distortion well.

[0091] From Figure 12 It can be seen that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0-120 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.

[0092] Embodiment 5 Please refer to Figure 13 , which shows the structural schematic diagram of the optical lens 500 provided in Embodiment 5 of the present invention. Compared with Embodiment 1, the main differences are: the aperture stop ST is arranged between the second lens L2 and the third lens L3; the image side surface S12 of the sixth lens L6 is concave; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0093] The relevant parameters of each lens in the optical lens 500 in Embodiment 5 are shown in Table 5-1.

[0094] Table 5-1 The aspheric lens surface type parameters of the optical lens 500 in Embodiment 5 are shown in Table 5-2.

[0095] Table 5-2 In this embodiment, the F-Tan(Theta) distortion curve diagram and MTF curve diagram of the optical lens 500 are respectively as shown in Figure 14 , Figure 15 shown.

[0096] From Figure 14 It can be seen that the distortion of the optical lens is controlled within -20% to 0, indicating that the optical lens 500 can correct the distortion well.

[0097] From Figure 15 It can be seen that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0-120 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.

[0098] Please refer to Table 6 for the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the true image height IH corresponding to the maximum field of view angle, the chief ray angle of incidence CRA at the maximum image height, the maximum field of view angle FOV, and the values corresponding to each conditional formula in each embodiment.

[0099] Table 6 In summary of the above embodiments, the optical lens provided by the present invention uses six lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberration, and enhance the imaging quality of the optical lens, enabling the lens to have one or more advantages such as miniaturization, large target surface, large aperture, large field of view angle, and high imaging quality.

[0100] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations 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.

[0101] The above-described embodiments only represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting 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, consisting of six lenses in total, characterized in that, It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with negative optical power, whose object side is concave and whose image side is concave; A second lens with positive optical power, whose object side is convex and whose image side is concave; A third lens with positive optical power, whose object side is convex and whose image side is convex; A fourth lens with positive optical power, whose object side is concave and whose image side is convex; A fifth lens with negative optical power, whose object side is concave and whose image side is convex; A sixth lens with positive optical power, whose object side is convex; Wherein, the radius of curvature R3 of the object side of the second lens and the radius of curvature R4 of the image side of the second lens satisfy: -0.9 < (R3 - R4) / (R3 + R4) < -0.1; The radius of curvature R9 of the object side of the fifth lens and the radius of curvature R10 of the image side of the fifth lens satisfy: -1 < (R9 - R10) / (R9 + R10) < -0.

2.

2. The optical lens according to claim 1, wherein, The overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.3 < TTL / f < 3.1; The overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 1.5 < TTL / IH < 2.

4.

3. 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 entrance pupil diameter EPD of the optical lens satisfy: 1.7 < IH / EPD < 3.2; The true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1 < IH / f < 1.

8.

4. The optical lens according to claim 1, wherein The clear aperture radius d1 of the object side of the first lens, the true image height IH corresponding to the maximum field of view angle of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 0.77 < d1 / (IH / 2) / tan(FOV / 2) < 1.67; The optical lens further includes a diaphragm, the diaphragm is located between the third lens and the fourth lens or between the second lens and the third lens, and the combined focal length ffront of the lenses in front of the diaphragm and the combined focal length fback of the lenses behind the diaphragm satisfy: 0 < ffront / fback < 4.

2.

5. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.8 < f1 / f < -0.9; The radius of curvature R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: -3.5 < R1 / f < -1.1; The radius of curvature R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: 1.1 < R2 / f < 3.

4.

6. The optical lens according to claim 1, wherein The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.3 < f2 / f < 25; The radius of curvature R3 of the object side of the second lens and the effective focal length f of the optical lens satisfy: 0.7 < R3 / f < 5; The radius of curvature R4 of the image side of the second lens and the effective focal length f of the optical lens satisfy: 2.7 < R4 / f < 11.

7. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.7 < f3 / f < 1; the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.6 < f6 / f < 25.

8. The optical lens according to claim 1, wherein The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 3 < f4 / f < 35; the object-side curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: -15 < R7 / f < -3.2; the image-side curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -3.4 < R8 / f < -1.

3.

9. The optical lens according to claim 1, wherein, The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.7 < f5 / f < -0.6; the object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: -0.65 < R9 / f < -0.1; the image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -12 < R10 / f < -0.

3.

10. The optical lens according to claim 1, characterized in that, The object-side curvature radius R7 of the fourth lens and the image-side curvature radius R8 of the fourth lens satisfy: 0 < (R7 - R8) / (R7 + R8) < 0.8; the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: -0.1 < (R1 + R2) / (R1 - R2) < 0.4.

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