Optical lens

Abstract

The invention provides an optical lens, which comprises seven lenses, and sequentially comprises 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 imaging surface, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the object side surface of the third lens is a convex surface; the object side surface and the image side surface of the fourth lens are convex surfaces; the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a concave surface; the sixth lens has negative focal power, and the object side surface and the image side surface of the sixth lens are concave surfaces; and the object side surface of the seventh lens is a convex surface, and the image side surface of the seventh lens is a concave surface. According to the optical lens provided by the invention, through specific surface shape matching and reasonable focal power distribution, the lens has one or more advantages of a large field angle, a large target surface, a large aperture, 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, in-vehicle application optical lenses are increasingly used in intelligent driving, and the status of in-vehicle optical lenses in the automotive-related industry is constantly rising.

[0003] Advanced Driver Assistance Systems (ADAS) play an important role in intelligent driving. It collects environmental information through various lenses and sensors to ensure the driving safety of the driver. In addition to requiring the optical lens to have a thin, light, short, and small shape and have characteristics such as high pixels and high resolution, the existing ADAS system 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 effect. Summary of the Invention

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

[0005] The technical solution adopted by the present invention is as follows:

[0006] An optical lens, comprising a total of seven lenses, which sequentially include, along the optical axis from the object side to the imaging surface:

[0007] A first lens with negative optical power, the object side surface thereof is convex, and the image side surface thereof is concave;

[0008] A second lens with negative optical power, the object side surface thereof is concave, and the image side surface thereof is convex;

[0009] A third lens with positive optical power, the object side surface thereof is convex;

[0010] A fourth lens with positive optical power, both the object side surface and the image side surface thereof are convex;

[0011] A fifth lens with positive optical power, the object side surface thereof is convex, and the image side surface thereof is concave;

[0012] A sixth lens with negative optical power, both the object side surface and the image side surface thereof are concave;

[0013] A seventh lens with positive optical power, the object side surface thereof is convex, and the image side surface thereof is concave;

[0014] Wherein, the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: 0.7 < (R11 + R12) / (R11 - R12) < 0.9.

[0015] More preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 8.2 < TTL / f < 8.6; 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: 3.8 < TTL / IH < 4.1.

[0016] More preferably, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 86° < FOV / Fno < 88°; 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: 3.3 < IH / EPD < 3.6.

[0017] More preferably, 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: 2.1 < IH / f < 2.2; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.72 < BFL / f < 0.75.

[0018] More preferably, the clear aperture 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: 0.58 < d1 / (IH / 2) / tan(FOV / 2) < 0.64; the combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens and the seventh lens satisfy: 2.8 < f123 / f4567 < 6.5.

[0019] More preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -29 < f2 / f < -10; the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 3.5 < f3 / f < 4.6.

[0020] More preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 4.4 < f5 / f < 6; the radius of curvature R9 of the object side of the fifth lens and the effective focal length f of the optical lens satisfy: 2.3 < R9 / f < 2.8; the radius of curvature R10 of the image side of the fifth lens and the effective focal length f of the optical lens satisfy: 13 < R10 / f < 22.

[0021] More preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -2 < f6 / f < -1.7; the object-side curvature radius R11 of the sixth lens and the effective focal length f of the optical lens satisfy: -22 < R11 / f < -13; the image-side curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.7 < R12 / f < 2.2.

[0022] More preferably, the object-side curvature radius R9 of the fifth lens and the image-side curvature radius R10 of the fifth lens satisfy: -1.6 < (R9 + R10) / (R9 - R10) < -1.2.

[0023] More preferably, the object-side clear aperture semi-diameter d11 of the sixth lens and the object-side clear aperture sagitta Sag11 of the sixth lens satisfy: -0.05 < Sag11 / d11 < -0.01; the image-side clear aperture semi-diameter d12 of the sixth lens and the image-side clear aperture sagitta Sag12 of the sixth lens satisfy: 0.22 < Sag12 / d12 < 0.27.

[0024] The optical lens provided by the present invention adopts seven 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 endow the lens with one or more advantages such as a large field of view, a large target surface, a large aperture, and high imaging quality. Description of the Drawings

[0025] 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:

[0026] Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0027] Figure 2 is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3 is the MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 4 is the axial aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 5 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0031] Figure 6This is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 7 This is the MTF curve graph of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 8 This is the axial aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0034] Figure 9 This is the structural schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0035] Figure 10 This is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0036] Figure 11 This is the MTF curve graph of the optical lens in Embodiment 3 of the present invention.

[0037] Figure 12 This is the axial aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0038] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0039] To better understand the present application, various aspects of the present application will be described in more detail 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.

[0040] 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.

[0041] In the drawings, for the sake of clarity, the thickness, dimensions and shape 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 for illustrative purposes only and are not drawn to an exact scale.

[0042] In this text, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object being 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.

[0043] It should also be understood that the terms "comprising", "including", "having", "containing" and / or "including having", when used in this specification, mean the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when an expression such as "at least one of..." appears after 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 the 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.

[0044] 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.

[0045] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0046] The optical lens provided by the embodiment of the present invention has a total of seven lenses, which are, in order from the object side to the imaging surface along the optical axis, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens.

[0047] In some embodiments, the first lens may have a negative optical power, its object side surface is convex, and its image side surface is concave. The second lens may have a negative optical power, its object side surface is concave, and its image side surface is convex. The third lens may have a positive optical power, its object side surface is convex, and its image side surface may be concave or convex. The fourth lens may have a positive optical power, and both its object side surface and image side surface are convex. The fifth lens may have a positive optical power, its object side surface is convex, and its image side surface is concave. The sixth lens may have a negative optical power, and both its object side surface and image side surface are concave. The seventh lens may have a positive optical power, its object side surface is convex, and its image side surface is concave.

[0048] In some embodiments, the optical lens may further include a diaphragm, which may be located between the third lens and the fourth lens. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the image. Additionally, when the diaphragm is located between the third lens and the fourth lens, the diaphragm can reasonably distribute the functions of the first lens to the seventh lens. For example, the first lens, the second lens, and the third lens can be used to receive light to a greater extent, and the fourth lens to the seventh lens can be used to correct aberrations, which is beneficial to balancing the structure of the entire optical system. Furthermore, when the diaphragm is located between the third lens and the fourth lens, it is convenient to correct the diaphragm aberration.

[0049] In some embodiments, the optical lens may further include a filter and a protective glass, which may be sequentially arranged along the optical axis between the seventh 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. The protective glass plays a role in protecting the optical lens, preventing the photosensitive chip from being damaged, and can improve the anti-impact and scratch-resistant capabilities of the optical lens, while having little impact on the imaging quality of the optical lens.

[0050] In some embodiments, the object-side curvature radius R11 and the image-side curvature radius R12 of the sixth lens satisfy: 0.7 < (R11 + R12) / (R11 - R12) < 0.9. Satisfying the above range is beneficial to increasing the divergence degree of light, increasing the area of light entering the imaging surface, achieving large-format imaging of the lens, and improving the imaging quality of the optical lens. More specifically, 0.71 < (R11 + R12) / (R11 - R12) < 0.86.

[0051] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 8.2 < TTL / f < 8.6. Satisfying the above range can effectively limit the length of the lens, which is beneficial to realizing the miniaturization of the optical lens. More specifically, 8.29 < TTL / f < 8.55.

[0052] 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: 3.8 < TTL / IH < 4.1. Satisfying the above range ensures that the lens has a larger image surface under the same total length of the lens, can match a larger-size imaging chip to achieve high-definition imaging, and better realizes the balance between the small total length and the large image surface of the lens. More specifically, 3.89 < TTL / IH < 4.05.

[0053] In some embodiments, the maximum field of view (FOV) of the optical lens and the f-number (Fno) of the optical lens satisfy: 86° < FOV / Fno < 88°. Meeting the above range defines that the optical lens has an appropriate field of view and f-number, can collect light at large angles, and obtain good imaging quality. More specifically, 86.05° < FOV / Fno < 87.94°.

[0054] In some embodiments, the true image height (IH) corresponding to the maximum field of view of the optical lens and the entrance pupil diameter (EPD) of the optical lens satisfy: 3.3 < IH / EPD < 3.6. Meeting the above range can increase the width of the light beam incident on the optical lens, improve the brightness at the image plane of the optical lens, and avoid vignetting. More specifically, 3.39 < IH / EPD < 3.52.

[0055] In some embodiments, the true image height (IH) corresponding to the maximum field of view of the optical lens and the effective focal length (f) of the optical lens satisfy: 2.1 < IH / f < 2.2. 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, 2.1 < IH / f < 2.14.

[0056] In some embodiments, the effective focal length (f) of the optical lens and the back focal length (BFL) of the optical lens satisfy: 0.72 < BFL / f < 0.75. Meeting the above range defines that the optical lens has an appropriate back focus, which facilitates the reasonable arrangement of the positions of each lens and reduces the processing and assembly difficulty.

[0057] In some embodiments, the clear aperture (d1) of the object side surface of the first lens, the true image height (IH) corresponding to the maximum field of view of the optical lens, and the maximum field of view (FOV) of the optical lens satisfy: 0.58 < d1 / (IH / 2) / tan(FOV / 2) < 0.64. Meeting the above range can have a small front aperture while meeting the requirements of the optical lens having a large field of view and a large image plane.

[0058] In some embodiments, the combined focal length (f123) of the first lens, the second lens, and the third lens and the combined focal length (f4567) of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfy: 2.8 < f123 / f4567 < 6.5. Meeting the above range, by reasonably setting the focal length relationship of the lens groups before and after the aperture stop, it is beneficial to balance various aberrations generated by the lens groups before and after the aperture stop and improve the overall imaging quality. More specifically, 2.85 < f123 / f4567 < 6.5.

[0059] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -29 < f2 / f < -10. Meeting the above range enables the second lens to have a negative optical power, which can share the negative optical power at the front end of the optical lens, thus facilitating the avoidance of excessive light deflection caused by overly concentrated optical power of the first lens and reducing the difficulty of aberration correction of the optical lens. More specifically, -28.21 < f2 / f < -10.47.

[0060] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 3.5 < f3 / f < 4.6. Meeting the above range defines that the third lens has an appropriate positive optical power, which has the effect of converging light rays, depressing the height of peripheral light rays, facilitating the reduction of the aperture of the rear lens, and at the same time facilitating the balance of aberrations and improving the resolution. More specifically, 3.58 < f3 / f < 4.58.

[0061] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 4.4 < f5 / f < 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: 2.3 < R9 / f < 2.8; 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: 13 < R10 / f < 22. Meeting the above range, setting the fifth lens to have a positive refractive power and a suitable surface shape is beneficial to converging light rays while correcting the aberrations of the optical lens and improving the imaging quality of the optical lens. More specifically, 4.4 < f5 / f < 5.57; 2.35 < R9 / f < 2.78; 13.2 < R10 / f < 21.57.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -2 < f6 / f < -1.7; the radius of curvature R11 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -22 < R11 / f < -13; the radius of curvature R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 1.7 < R12 / f < 2.2. Meeting the above range can effectively balance various aberrations generated by the front lens group, and at the same time is beneficial to increasing the divergence degree of light rays, increasing the area of light rays entering the imaging surface, realizing large target surface imaging of the lens, and improving the imaging quality of the optical lens. More specifically, -1.94 < f6 / f < -1.74; -21.93 < R11 / f < -13.13; 1.76 < R12 / f < 2.13.

[0063] In some embodiments, the radius of curvature R9 of the object side surface of the fifth lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: -1.6 < (R9 + R10) / (R9 - R10) < -1.2. Meeting the above range is conducive to light convergence, enabling the light trend to smoothly transition to the rear, facilitating the correction of the aberration of the entire optical lens, and improving the imaging quality of the optical lens; at the same time, it reduces the height of the light incident on the rear, slows down the upward trend of the light, and avoids the light energy loss caused by the excessive main ray angle between the large field-of-view light and the chip when reaching the imaging surface, which is beneficial to improving the illuminance of the edge field of view. More specifically, -1.54 < (R9 + R10) / (R9 - R10) < -1.24.

[0064] In some embodiments, the clear aperture semi-diameter d11 of the object side surface of the sixth lens and the sagittal height Sag11 of the clear aperture of the object side surface of the sixth lens satisfy: -0.05 < Sag11 / d11 < -0.01; the clear aperture semi-diameter d12 of the image side surface of the sixth lens and the sagittal height Sag12 of the clear aperture of the image side surface of the sixth lens satisfy: 0.22 < Sag12 / d12 < 0.27. Meeting the above range helps to control the trend of the edge field-of-view light and highlight the detailed information of the central field of view of the optical lens.

[0065] In some embodiments, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis satisfy: 0.56 < ∑CT / TTL < 0.59. Meeting the above range can effectively compress the total length of the optical lens, and is conducive to the structural design and production process of the optical lens.

[0066] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis and the effective focal length f of the optical lens satisfy: 4.7 < ΣCT / f < 5. 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. More specifically, 4.79 < ΣCT / f < 4.95.

[0067] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2 < f1 / f < -1.8. Meeting the above range, by setting the first lens to have a negative refractive power, it is beneficial for the first lens to accommodate a larger angle of light and collect as much light as possible into the rear optical system, achieving a large field of view while increasing the light flux. More specifically, -1.97 < f1 / f < -1.88.

[0068] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 2.5 < f4 / f < 2.8. Meeting the above range defines that the fourth lens has an appropriate positive optical power, and the light is further converged, which is beneficial to making the light enter the rear lens smoothly, can adjust the optical path difference between different fields of view, and improve the resolution. More specifically, 2.57 < f4 / f < 2.74.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 3.2 < f7 / f < 3.6; the curvature radius R13 of the object side surface of the seventh lens and the effective focal length f of the optical lens satisfy: 2.1 < R13 / f < 2.5; the curvature radius R14 of the image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: 10 < R14 / f < 11. Meeting the above range, setting the seventh lens to have a positive refractive power and a suitable surface shape is beneficial to light convergence, making the light trend transition smoothly to the rear, reducing the height of the light incident on the rear, avoiding the light energy loss caused by the excessive chief ray angle of the large field of view light when reaching the imaging surface, being conducive to improving the illuminance of the edge field of view, and being beneficial to achieving a short overall optical length. More specifically, 3.2 < f7 / f < 3.54; 2.17 < R13 / f < 2.46; 10.02 < R14 / f < 10.43.

[0070] In some embodiments, the combined focal length f123 of the first lens, the second lens and the third lens and the effective focal length f of the optical lens satisfy: 7 < f123 / f < 17; the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 2.4 < f4567 / f < 2.7. Meeting the above range, by reasonably setting the relationship between the focal lengths of the lens groups before and after the aperture and the effective focal length of the optical lens, it is beneficial to balance various aberrations generated by the lens groups before and after the aperture and improve the overall imaging quality. More specifically, 7.59 < f123 / f < 16.13; 2.47 < f4567 / f < 2.66.

[0071] In some embodiments, the optical lens satisfies the following conditional expressions: 4.1 mm < f < 4.2 mm; 2.5 mm < EPD < 2.6 mm; 34 mm < TTL < 36 mm; 1.6 < Fno < 1.7; 12° < CRA < 21°; 3 mm < BFL < 3.1 mm; 140° < FOV < 145°; 8.7 mm < IH < 9 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, FNO represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the chief ray angle of incidence of the optical lens, and BFL represents the back focal length of the optical lens. Meeting the above ranges, the optical lens has at least one or more advantages such as a large field of view angle, a large target surface, and a large aperture. More specifically, 2.53 mm < EPD < 2.58 mm; 34.73 mm < TTL < 35.33 mm; 1.61 < Fno < 1.66; 12.15° < CRA < 20.86°; 3.05 mm < BFL < 3.08 mm; 141° < FOV < 143°; 8.72 mm < IH < 8.91 mm.

[0072] In some embodiments, the lens material of 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. Additionally, when the lens material is glass, due to the low dispersion characteristic of the glass itself, the geometric chromatic aberration of the optical system can be effectively corrected. The optical lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0073] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh 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 fourth lens of the present invention adopts an aspherical lens; the first lens, the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens adopt spherical lenses.

[0074] In various embodiments of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations:

[0075]

[0076] Among them, z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the conic coefficient, and B, C, D, E, and F are the conic coefficients of the fourth, sixth, eighth, tenth, and twelfth orders respectively.

[0077] The present invention will be further described below with multiple embodiments. In each embodiment, the thickness, curvature radius, and material selection of each lens in the optical lens are partially different. For specific differences, refer to the parameter tables of each embodiment. The following embodiments are only 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.

[0078] Embodiment 1

[0079] Please refer to Figure 1 , which shows a schematic structural diagram of an 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, a seventh lens L7, a filter G1, and a protective glass G2.

[0080] Among them, the first lens L1 has a negative optical power. Its object side surface S1 is a convex surface, and its image side surface S2 is a concave surface;

[0081] The second lens L2 has a negative optical power. Its object side surface S3 is a concave surface, and its image side surface S4 is a convex surface;

[0082] The third lens L3 has a positive optical power. Its object side surface S5 is a convex surface, and its image side surface S6 is a concave surface;

[0083] The fourth lens L4 has a positive optical power. Both its object side surface S7 and image side surface S8 are convex surfaces;

[0084] The fifth lens L5 has a positive optical power. Its object side surface S9 is a convex surface, and its image side surface S10 is a concave surface;

[0085] The sixth lens L6 has a negative optical power. Its object side surface S11 is a concave surface, and its image side surface S12 is a concave surface;

[0086] The seventh lens L7 has a positive optical power. Its object side surface S13 is a convex surface, and its image side surface S14 is a concave surface;

[0087] Both the object side surface S15 and the image side surface S16 of the filter G1 are flat surfaces;

[0088] Both the object side surface S17 and the image side surface S18 of the protective glass G2 are flat surfaces;

[0089] The imaging surface S19 is a plane.

[0090] The fourth lens L4 is a glass aspherical lens; the first lens L1, the second lens L2, the third lens L3, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are glass spherical lenses.

[0091] The relevant parameters of each lens in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0092] Table 1-1

[0093]

[0094]

[0095] The surface type parameters of the aspherical lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0096] Table 1-2

[0097] Face number K B C D E F S7 -1.78E+01 -3.45E-04 1.09E-04 -3.59E-05 3.56E-06 -1.36E-07 S8 1.71E+00 2.17E-04 2.72E-06 -1.03E-06 7.84E-08 -2.12E-09

[0098] In this embodiment, the F-Tan(Theta) distortion curve, MTF curve graph, and axial aberration curve graph of the optical lens 100 are respectively as Figure 2 , Figure 3 , Figure 4 shown.

[0099] Figure 2 shows the F-Tan(Theta) distortion curve of Embodiment 1, which represents the F-Tan(Theta) distortion of light rays with different wavelengths at different image heights on the imaging surface. The horizontal axis represents the F-Tan(Theta) distortion value (unit: %), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the F-Tan(Theta) distortion of the optical lens is controlled within -65% to 0, and the image compression in the edge angle region is relatively gentle, effectively improving the clarity of the expanded image.

[0100] Figure 3 Figure 3 shows the MTF (Modulation Transfer Function) curve graph of Embodiment 1, which represents the modulation of the 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 in this embodiment is above 0.35 in 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 field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0101] Figure 4The axial aberration curve of Embodiment 1 is shown, which represents the aberration on the optical axis at the imaging plane for each wavelength. The horizontal axis represents the axial aberration value (unit: mm), 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 -0.02 mm to 0.06 mm, indicating that the optical lens can correct the axial aberration well.

[0102] Embodiment 2

[0103] Please refer to Figure 5 , which shows the schematic structural diagram of the optical lens 200 provided in Embodiment 2 of the present invention. Compared with Embodiment 1, the main differences are as follows: The image side S6 of the third lens L3 is a convex surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0104] The relevant parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0105] Table 2-1

[0106]

[0107] The surface type parameters of the aspherical lenses of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0108] Table 2-2

[0109] Face number K B C D E F S7 -9.48E+00 -8.08E-04 9.06E-05 -2.35E-05 2.21E-06 -8.06E-08 S8 6.23E-01 7.78E-05 5.08E-06 -1.45E-06 8.23E-08 -2.13E-09

[0110] In this embodiment, the F-Tan(Theta) distortion curve, MTF curve graph, and axial aberration curve graph of the optical lens 200 are respectively as shown in Figure 6 , Figure 7 , Figure 8 .

[0111] From Figure 6 , it can be seen that the F-Tan(Theta) distortion of the optical lens is controlled within -65% to 0, and the image compression in the edge angle region is relatively gentle, effectively improving the clarity of the unfolded image.

[0112] From Figure 7 , 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 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.

[0113] From Figure 8 , it can be seen that the offset of the axial aberration is controlled within -0.02 mm to 0.05 mm, indicating that the optical lens can correct the axial aberration well.

[0114] Example 3

[0115] Please refer to Figure 9 , which shows the schematic structural 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 S6 of the third lens L3 is a convex surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0116] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0117] Table 3-1

[0118]

[0119]

[0120] The surface type parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0121] Table 3-2

[0122] Face number K B C D E F S7 -1.78E+01 -3.45E-04 1.09E-04 -3.59E-05 3.56E-06 -1.36E-07 S8 1.71E+00 2.17E-04 2.72E-06 -1.03E-06 7.84E-08 -2.12E-09

[0123] In this embodiment, the F-Tan(Theta) distortion curve, MTF curve graph, and axial aberration curve graph of the optical lens 300 are respectively as shown in Figure 10 , Figure 11 , Figure 12 .

[0124] It can be seen from Figure 10 that the F-Tan(Theta) distortion of the optical lens is controlled within -65% to 0, indicating that the optical lens can correct the distortion well.

[0125] It can be seen from Figure 11 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.

[0126] It can be seen from Figure 12 that the offset of the axial aberration is controlled within -0.02 mm to 0.05 mm, indicating that the optical lens can correct the axial aberration well.

[0127] Please refer to Table 4 for the optical characteristics corresponding to the above embodiments, including the effective focal length f, the overall optical length TTL, the aperture value Fno, the true image height IH corresponding to the maximum field of view angle, the maximum field of view angle FOV, and the numerical values corresponding to each conditional formula in each embodiment.

[0128] Table 4

[0129]

[0130]

[0131] In summary of the above embodiments, the optical lens provided by the present invention adopts seven 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 a large field of view, a large target surface, a large aperture, and high imaging quality.

[0132] In the description of this specification, the description referring 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.

[0133] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. An optical lens, comprising seven lenses, characterized in that: It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with a negative optical power, whose object side surface is convex and whose image side surface is concave; A second lens with a negative optical power, whose object side surface is concave and whose image side surface is convex; A third lens with a positive optical power, whose object side surface is convex; A fourth lens with a positive optical power, whose object side surface and image side surface are both convex; A fifth lens with a positive optical power, whose object side surface is convex and whose image side surface is concave; A sixth lens with a negative optical power, whose object side surface and image side surface are both concave; A seventh lens with a positive optical power, whose object side surface is convex and whose image side surface is concave; Wherein, the curvature radius R11 of the object side surface of the sixth lens and the curvature radius R12 of the image side surface of the sixth lens satisfy: 0.7 < (R11 + R12) / (R11 - R12) < 0.

9.

2. The optical lens according to claim 1, characterized in that: The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 8.2 < TTL / f < 8.6; 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: 3.8 < TTL / IH < 4.

1.

3. The optical lens according to claim 1, characterized in that: The maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 86° < FOV / Fno < 88°; 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: 3.3 < IH / EPD < 3.

6.

4. The optical lens according to claim 1, characterized in that: 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: 2.1 < IH / f < 2.2; The effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.72 < BFL / f < 0.

75.

5. The optical lens according to claim 1, characterized in that: The 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: 0.58 < d1 / (IH / 2) / tan(FOV / 2) < 0.64; The combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens and the seventh lens satisfy: 2.8 < f123 / f4567 < 6.

5.

6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -29 < f2 / f < -10; The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 3.5 < f3 / f < 4.

6.

7. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 4.4 < f5 / f < 6; The curvature radius R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 2.3 < R9 / f < 2.8; The curvature radius R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 13 < R10 / f < 22.

8. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -2 < f6 / f < -1.7; the object-side curvature radius R11 of the sixth lens and the effective focal length f of the optical lens satisfy: -22 < R11 / f < -13; the image-side curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.7 < R12 / f < 2.

2.

9. The optical lens according to claim 1, characterized in that: The object-side curvature radius R9 of the fifth lens and the image-side curvature radius R10 of the fifth lens satisfy: -1.6 < (R9 + R10) / (R9 - R10) < -1.

2.

10. The optical lens according to claim 1, characterized in that: The object-side clear aperture semi-diameter d11 of the sixth lens and the object-side clear aperture sagittal height Sag11 of the sixth lens satisfy: -0.05 < Sag11 / d11 < -0.01; the image-side clear aperture semi-diameter d12 of the sixth lens and the image-side clear aperture sagittal height Sag12 of the sixth lens satisfy: 0.22 < Sag12 / d12 < 0.27.

Images