Optical lens

Abstract

The invention provides an optical lens, which comprises seven lenses in total, and sequentially comprises a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with negative focal power, a fifth lens with positive focal power and a sixth lens with negative focal power from an object side to an imaging surface, the second lens has positive focal power; the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a concave surface; the object side surface of the fourth lens is a convex 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; the sixth lens has positive focal power, and the object side surface of the sixth lens is a convex surface; and the object 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 long focus, 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, 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] 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] In view of the above problems, the purpose of the present invention is to provide an optical lens, which has the advantage of excellent imaging quality.

[0005] The technical solution adopted by the present invention is as follows: An optical lens, comprising a total of seven lenses, which successively include, along the optical axis from the object side to the imaging surface: A first lens with positive optical power, the object side surface of which is convex and the image side surface of which is concave; A second lens with positive optical power; A third lens with negative optical power, the object side surface of which is concave and the image side surface of which is concave; A fourth lens with positive optical power, the object side surface of which is convex 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; A seventh lens with negative optical power, the object side surface of which is concave; Wherein, the curvature radius R1 of the object side surface of the first lens and the curvature radius R2 of the image side surface of the first lens satisfy: -0.8 < (R1 - R2) / (R1 + R2) < -0.1; the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: |(R5 + R6) / (R5 - R6)| < 0.9.

[0006] More preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2 < TTL / f < 2.5; 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: 4 < TTL / IH < 4.8.

[0007] More preferably, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 15° < FOV / Fno < 20°; 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: 0.8 < IH / EPD < 1.

[0008] More preferably, 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: 6.5 < d1 / (IH / 2) / tan(FOV / 2) < 8.5; 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: -37 < f123 / f4567 < -5.5.

[0009] More preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.3 < f1 / f < 5.5; the curvature radius R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: 0.85 < R1 / f < 1.6; the curvature radius R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: 2 < R2 / f < 5.8.

[0010] More preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.7 < f3 / f < -0.6; the curvature radius R5 of the object side of the third lens and the effective focal length f of the optical lens satisfy: -4 < R5 / f < -1.3; the curvature radius R6 of the image side of the third lens and the effective focal length f of the optical lens satisfy: 0.4 < R6 / f < 3.

[0011] More preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.4 < f4 / f < 0.7; the curvature radius R7 of the object side of the fourth lens and the effective focal length f of the optical lens satisfy: 0.6 < R7 / f < 0.8; the curvature radius R8 of the image side of the fourth lens and the effective focal length f of the optical lens satisfy: -0.65 < R8 / f < -0.3.

[0012] More preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -2 < f5 / f < -0.9; 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 < -0.3; 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: -1.2 < R10 / f < -0.6.

[0013] More preferably, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -0.9 < f7 / f < -0.5; the radius of curvature R13 of the object side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -1.1 < R13 / f < -0.4.

[0014] More preferably, 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: -0.5 < (R9 - R10) / (R9 + R10) < -0.1; 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) < 0.5.

[0015] 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 make the lens have one or more advantages such as long focal length, large aperture, 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 field curvature curve graph of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 3 is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 1 of the present invention.

[0019] Figure 4 is the MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0020] Figure 5 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0021] Figure 6 is a field curvature curve graph of the optical lens in Embodiment 2 of the present invention.

[0022] Figure 7 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0023] Figure 8 It is the MTF curve graph of the optical lens in Embodiment 2 of the present invention.

[0024] Figure 9 It is the structural schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0025] Figure 10 It is the field curvature curve graph of the optical lens in Embodiment 3 of the present invention.

[0026] Figure 11 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0027] Figure 12 It is the MTF curve graph of the optical lens in Embodiment 3 of the present invention.

[0028] Figure 13 It is the structural schematic diagram of the optical lens in Embodiment 4 of the present invention.

[0029] Figure 14 It is the field curvature curve graph of the optical lens in Embodiment 4 of the present invention.

[0030] Figure 15 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 4 of the present invention.

[0031] Figure 16 It is the MTF curve graph of the optical lens in Embodiment 4 of the present invention.

[0032] Figure 17 It is the structural schematic diagram of the optical lens in Embodiment 5 of the present invention.

[0033] Figure 18 It is the field curvature curve graph of the optical lens in Embodiment 5 of the present invention.

[0034] Figure 19 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 5 of the present invention.

[0035] Figure 20 It is the MTF curve graph of the optical lens in Embodiment 5 of the present invention.

[0036] Figure 21 It is the structural schematic diagram of the optical lens in Embodiment 6 of the present invention.

[0037] Figure 22 It is the field curvature curve graph of the optical lens in Embodiment 6 of the present invention.

[0038] Figure 23 This is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 6 of the present invention.

[0039] Figure 24 This is the MTF curve graph of the optical lens in Embodiment 6 of the present invention.

[0040] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0041] To better understand the present application, more detailed descriptions will be made on various aspects of the present application with reference to the 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.

[0042] It should be noted that in this specification, the expressions such as first, second, and third are only used to distinguish one feature from another feature and do not represent any limitation on the features. Therefore, without departing from the teachings of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0043] In the drawings, for the sake of convenience of illustration, the thickness, size, and shape of the lens have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0044] In this article, 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.

[0045] It should also be understood that the terms "comprising", "comprises", "having", "including" and / or "includes", 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 and not an individual element in the list. Further, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the term "exemplary" is intended to refer to an example or illustration.

[0046] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that 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.

[0047] 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.

[0048] The optical lens provided by the embodiment of the present invention is composed of seven 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, a sixth lens and a seventh lens.

[0049] In some embodiments, the first lens may have a positive optical power, its object side surface is convex, and its image side surface is concave. The second lens may have a positive optical power, its object side surface may be concave or convex, and its image side surface may be concave or convex. The third lens may have a negative optical power, its object side surface is concave, and its image side surface is concave. The fourth lens may have a positive optical power, its object side surface is convex, and its image side surface is convex. The fifth lens may have a negative optical power, its object side surface is concave, and its image side surface is convex. The sixth lens may have a positive optical power, its object side surface is convex, and its image side surface may be concave or convex. The seventh lens may have a negative optical power, its object side surface is concave, and its image side surface may be concave or convex.

[0050] 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.

[0051] 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-shock and scratch-resistant capabilities of the optical lens, while having almost no impact on the imaging quality of the optical lens.

[0052] In some embodiments, the fourth lens and the fifth lens may be glued together to form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0053] In some embodiments, the curvature radius R1 of the object side surface of the first lens and the curvature radius R2 of the image side surface of the first lens satisfy: -0.8 < (R1 - R2) / (R1 + R2) < -0.1. When the above range is satisfied, using a meniscus lens for the first lens can further control the smooth trend of light, make the light more concentrated, can further control the light direction, reduce the back focal length, improve the imaging quality, increase the light utilization rate, and reduce the spherical aberration of the optical lens, thereby improving the imaging quality of the optical lens. More specifically, -0.7 < (R1 - R2) / (R1 + R2) < -0.17.

[0054] In some embodiments, the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: |(R5 + R6) / (R5 - R6)| < 0.9. When the above range is satisfied, using a biconcave lens for the third lens has the effect of diverging light, can disperse the central light and marginal light of each field of view, and can correct the aberration generated by the front lens. More specifically, -0.31 < (R5 + R6) / (R5 - R6) < 0.77.

[0055] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2 < TTL / f < 2.5. Meeting the above range can effectively limit the length of the lens, which is conducive to the miniaturization of the optical lens. More specifically, 2.17 < TTL / f < 2.44.

[0056] 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: 4 < TTL / IH < 4.8. Meeting the above range ensures that, with the same total length of the lens, it has a larger image plane, can match a larger-sized imaging chip to achieve high-definition imaging, and better realizes the balance between the small total length and the large image plane of the lens. More specifically, 4.24 < TTL / IH < 4.48.

[0057] In some embodiments, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 15° < FOV / Fno < 20°. Meeting the above range limits the optical lens to have an appropriate field of view angle and aperture value, can collect light at a large angle and obtain good imaging quality. More specifically, 15.78° < FOV / Fno < 18.83°.

[0058] 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: 0.8 < IH / EPD < 1. Meeting the above range can increase the width of the light beam entering the optical lens, so that the brightness at the image plane of the optical lens is improved and vignetting is avoided. More specifically, 0.86 < IH / EPD < 0.98.

[0059] In some embodiments, the clear aperture radius 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: 6.5 < d1 / (IH / 2) / tan(FOV / 2) < 8.5. 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. More specifically, 6.92 < d1 / (IH / 2) / tan(FOV / 2) < 7.87.

[0060] 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: -37 < f123 / f4567 < -5.5. Meeting the above range is conducive to balancing various aberrations of the system and improving the overall imaging quality by reasonably setting the focal length relationship of the lens groups before and after the aperture stop. More specifically, -33.93 < f123 / f4567 < -6.

[0061] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.3 < f1 / f < 5.5; 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: 0.85 < R1 / f < 1.6; 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: 2 < R2 / f < 5.8. Meeting the above ranges, by setting the first lens to have a positive refractive power and a suitable surface shape, it has the effect of converging light, reducing the height of peripheral light, and is beneficial to reducing the aperture of the rear lens. More specifically, 1.44 < f1 / f < 5.1; 0.91 < R1 / f < 1.48; 2.09 < R2 / f < 5.26.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.7 < f3 / f < -0.6; the radius of curvature R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy: -4 < R5 / f < -1.3; the radius of curvature R6 of the image side surface of the third lens and the effective focal length f of the optical lens satisfy: 0.4 < R6 / f < 3. Meeting the above ranges, the third lens has a negative optical power and a suitable surface shape, has the effect of diverging light, can disperse the central light and edge light of each field of view, and can correct the aberration generated by the front lens. More specifically, -1.55 < f3 / f < -0.62; -3.64 < R5 / f < -1.42; 0.45 < R6 / f < 2.69.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.4 < f4 / f < 0.7; 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: 0.6 < R7 / f < 0.8; 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: -0.65 < R8 / f < -0.3; 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) < 0.5. Meeting the above ranges, it is defined that the fourth lens has an appropriate positive optical power and surface shape, and the light is further converged. And gluing the fourth lens with positive optical power and the fifth lens with negative optical power 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, 0.47 < f4 / f < 0.61; 0.63 < R7 / f < 0.76; -0.6 < R8 / f < -0.35; 0.07 < (R7 + R8) / (R7 - R8) < 0.35.

[0064] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -2 < f5 / f < -0.9; 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 < -0.3; 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: -1.2 < R10 / f < -0.6; 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: -0.5 < (R9 - R10) / (R9 + R10) < -0.1. Satisfying the above ranges and defining the fifth lens to have an appropriate negative optical power and surface shape can diverge the light rays emitted by the fourth lens, making the light rays in the marginal field of view show an upward trend, which is beneficial for the image points on the imaging surface to be away from the optical axis, so as to facilitate 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, -1.84 < f5 / f < -0.99; -0.6 < R9 / f < -0.35; -1.08 < R10 / f < -0.68; -0.39 < (R9 - R10) / (R9 + R10) < -0.26.

[0065] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -0.9 < f7 / f < -0.5; the radius of curvature R13 of the object side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -1.1 < R13 / f < -0.4. Satisfying the above ranges 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, -0.83 < f7 / f < -0.55; -1.03 < R13 / f < -0.42.

[0066] 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: 0.5 < IH / f < 0.6. Satisfying the above ranges and controlling the image height and focal length of the optical lens within a reasonable range helps the optical lens to have the characteristic of a large image surface and improve the imaging quality. More specifically, 0.5 < IH / f < 0.56.

[0067] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.19 < BFL / f < 0.31. Satisfying the above ranges defines that the optical lens has an appropriate back focus, which is convenient for reasonably arranging the positions of the lenses and reduces the processing and assembly difficulty.

[0068] 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: 0.49 < ∑CT / TTL < 0.64. Meeting the above range can effectively compress the total length of the optical lens, and is beneficial to the structural design and production process of the optical lens.

[0069] 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: 1.09 < ΣCT / f < 1.55. 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.

[0070] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 2.5 < f2 / f < 38. Meeting the above range defines that the second lens has an appropriate positive optical power, further converges the light rays, and can share the positive optical power at the front end of the optical lens, thus helping to avoid excessive light deflection caused by overly concentrated optical power of the first lens and reducing the difficulty of aberration correction. More specifically, 2.82 < f2 / f < 34.68.

[0071] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 0.6 < f6 / f < 3.9; 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: 0.7 < R11 / f < 1.6. Meeting the above range defines that the sixth lens has a positive optical power, which is beneficial to light convergence, enables the light ray trend to smoothly transition to the rear, reduces the height of the light rays incident on the rear, slows down the upward trend of the light rays, avoids light energy loss caused by too large an angle between the main light ray of the large field of view and the chip when the light rays reach the imaging surface, is beneficial to improving the illuminance of the edge field of view, and is beneficial to achieving a short total optical length. More specifically, 0.66 < f6 / f < 3.57; 0.77 < R11 / f < 1.44.

[0072] In some embodiments, the optical lens satisfies the following conditional expressions: 12 mm < f < 17 mm; 7 mm < EPD < 10 mm; 33 mm < TTL < 35 mm; 1.6 < Fno < 2; 16° < CRA < 26°; 3 mm < BFL < 4.4 mm; 29° < FOV < 33°; 7 mm < IH < 8.5 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 ranges, the optical lens has at least one or more advantages such as a large target surface, a large aperture, and a long focal length characteristic. More specifically, 13.88 mm < f < 15.58 mm; 7.78 mm < EPD < 9.17 mm; 33.7 mm < TTL < 34.1 mm; 1.69 < Fno < 1.91; 16.25° < CRA < 25.12°; 3.03 mm < BFL < 4.32 mm; 29.9° < FOV < 32.1°; 7.5 mm < IH < 8.1 mm.

[0073] 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. 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.

[0074] 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 lens 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, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens of the present invention adopt spherical lenses.

[0075] 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 somewhat 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.

[0076] Example 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, a seventh lens L7, a filter G1, and a protective glass G2.

[0077] Among them, the first lens L1 has a positive optical power. Its object side S1 is a convex surface, and its image side S2 is a concave surface; The second lens L2 has a positive optical power. Its object side S3 is a convex surface, and its image side S4 is a convex surface; The third lens L3 has a negative optical power. Its object side S5 is a concave surface, and its image side S6 is a concave surface; The fourth lens L4 has a positive optical power. Its object side S7 is a convex surface, and its image side is a convex surface; The fifth lens L5 has a negative optical power. Its object side is a concave surface, and its image side S9 is a convex surface; The fourth lens L4 and the fifth lens L5 form a cemented lens group with a positive optical power, that is, the cemented surface of the image side of the fourth lens L4 and the object side of the fifth lens L5 is S8; The sixth lens L6 has a positive optical power. Its object side S10 is a convex surface, and its image side S11 is a concave surface; The seventh lens L7 has a negative optical power. Its object side S12 is a concave surface, and its image side S13 is a concave surface; The object side S14 and the image side S15 of the filter G1 are both flat surfaces; The object side S16 and the image side S17 of the protective glass G2 are both flat surfaces; The imaging surface S18 is a flat surface.

[0078] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 adopt glass spherical lenses.

[0079] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1.

[0080] Table 1 In this embodiment, the field curvature curve, the F-Tan(Theta) distortion curve, and the MTF curve of the optical lens 100 are respectively as Figure 2 , Figure 3 , Figure 4 shown.

[0081] Figure 2 The field curvature curve of Embodiment 1 is shown, which represents the bending degree of light rays with different wavelengths in the meridional image plane and the sagittal image plane. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.01 mm to 0.05 mm, indicating that the optical lens can well correct the field curvature.

[0082] Figure 3 The F-Tan(Theta) distortion curve of Embodiment 1 is shown, which represents the F-Tan(Theta) distortion of light rays with different wavelengths at different image heights on the imaging plane. 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 -6% to 0, indicating that the optical lens can better correct the distortion.

[0083] Figure 4 The MTF (Modulation Transfer Function) curve graph of Embodiment 1 is shown, 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 0.4 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.

[0084] Embodiment 2 Please refer to Figure 5 , 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 image side surface S11 of the sixth lens L6 is a convex surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0085] The relevant parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2.

[0086] Table 2 In this embodiment, the field curvature curve graph, F-Tan(Theta) distortion curve graph, and MTF curve graph of the optical lens 200 are respectively as Figure 6 , Figure 7 , Figure 8 shown. It can be seen from Figure 6 that the field curvature of the meridional image plane and the sagittal image plane is controlled within 0 to 0.05 mm, indicating that the optical lens can well correct the field curvature. It can be seen from Figure 7It can be seen that the F-Tan(Theta) distortion of the optical lens is controlled within -5% to 0, indicating that the optical lens can correct distortion well. From Figure 8 It can be seen that the MTF value of this embodiment is above 0.38 in the entire field of view. In the range of 0 to 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.

[0087] Embodiment 3 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 surface S4 of the second lens L2 is concave; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0088] The relevant parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3.

[0089] Table 3 In this embodiment, the field curvature curve, F-Tan(Theta) distortion curve, and MTF curve of the optical lens 300 are respectively as shown in Figure 10 , Figure 11 , Figure 12 shown. From Figure 10 it can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.02 mm to 0.04 mm, indicating that the optical lens can correct field curvature well. From Figure 11 it can be seen that the F-Tan(Theta) distortion of the optical lens is controlled within -6% to 0, indicating that the optical lens can correct distortion well. From Figure 12 it can be seen that the MTF value of this embodiment is above 0.48 in the entire field of view. In the range of 0 to 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.

[0090] Embodiment 4 Please refer to Figure 13 , which shows the schematic structural diagram of the optical lens 400 provided in Embodiment 4 of the present invention. Compared with Embodiment 1, the main difference is that the object side surface S3 of the second lens L2 is concave; the image side surface S11 of the sixth lens L6 is convex; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0091] The relevant parameters of each lens in the optical lens 400 in Embodiment 4 are shown in Table 4.

[0092] Table 4 In this embodiment, the field curvature curve graph, F-Tan(Theta) distortion curve, and MTF curve graph of the optical lens 400 are respectively as shown in Figure 14 , Figure 15 , Figure 16 as shown. It can be seen from Figure 14 that the field curvature of the meridional image plane and the sagittal image plane is controlled within 0 to 0.05 mm, indicating that the optical lens can well correct the field curvature. It can be seen from Figure 15 that the F-Tan(Theta) distortion of the optical lens is controlled within -4% to 0, indicating that the optical lens can better correct the distortion. It can be seen from Figure 16 that the MTF value of this embodiment is above 0.3 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 of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0093] Embodiment 5 Please refer to Figure 17 , 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 difference is that: the image side surface S13 of the seventh lens L7 is a convex surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0094] The relevant parameters of each lens in the optical lens 500 in Embodiment 5 are shown in Table 5.

[0095] Table 5 In this embodiment, the field curvature curve graph, F-Tan(Theta) distortion curve, and MTF curve graph of the optical lens 500 are respectively as shown in Figure 18 , Figure 19 , Figure 20 as shown. It can be seen from Figure 18 that the field curvature of the meridional image plane and the sagittal image plane is controlled within 0 to 0.05 mm, indicating that the optical lens can well correct the field curvature. It can be seen from Figure 19 that the F-Tan(Theta) distortion of the optical lens is controlled within -4% to 0, indicating that the optical lens can better correct the distortion. It can be seen from Figure 20 that the MTF value of this embodiment is above 0.45 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 of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0096] Example 6 Please refer to Figure 21 , which shows a schematic structural diagram of the optical lens 600 provided in Example 6 of the present invention. Compared with Example 1, the main differences are as follows: the image side S4 of the second lens L2 is concave; the image side S11 of the sixth lens L6 is convex; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0097] The relevant parameters of each lens in the optical lens 600 in Example 6 are shown in Table 6.

[0098] Table 6 In this embodiment, the field curvature curve graph, F-Tan(Theta) distortion curve, and MTF curve graph of the optical lens 600 are respectively as shown in Figure 22 , Figure 23 , Figure 24 shown. It can be seen from Figure 22 that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.02 mm to 0.05 mm, indicating that the optical lens can well correct the field curvature. It can be seen from Figure 23 that the F-Tan(Theta) distortion of the optical lens is controlled within -4% to 0, indicating that the optical lens can better correct the distortion. It can be seen from Figure 24 that the MTF value of this embodiment is above 0.45 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.

[0099] Please refer to Table 7, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total 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 values corresponding to each conditional formula in each embodiment.

[0100] Table 7 In summary of the above embodiments, the optical lens provided by the present invention uses 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 improve the imaging quality of the optical lens, enabling the lens to have one or more advantages such as long focal length, large aperture, and high imaging quality.

[0101] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic 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 any one or more embodiments or examples in a suitable manner.

[0102] The above-described embodiments merely 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 for 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 for the present invention shall be subject to the appended claims.

Claims

1. An optical lens, consisting of seven lenses in total, characterized in that, It successively includes from the object side to the imaging surface along the optical axis: A first lens with positive optical power, whose object side is convex and whose image side is concave; A second lens with positive optical power; A third lens with negative optical power, whose object side is concave and whose image side is concave; A fourth lens with positive optical power, whose object side is convex 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; A seventh lens with negative optical power, whose object side is concave; Wherein, the curvature radius R1 of the object side of the first lens and the curvature radius R2 of the image side of the first lens satisfy: -0.8 < (R1 - R2) / (R1 + R2) < -0.1; the curvature radius R5 of the object side of the third lens and the curvature radius R6 of the image side of the third lens satisfy: |(R5 + R6) / (R5 - R6)| < 0.

9.

2. The optical lens according to claim 1, wherein The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2 < TTL / f < 2.5; 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: 4 < TTL / IH < 4.

8.

3. The optical lens according to claim 1, wherein The maximum field of view angle FOV of the optical lens and the f-number Fno of the optical lens satisfy: 15° < FOV / Fno < 20°; 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: 0.8 < IH / EPD < 1.

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: 6.5 < d1 / (IH / 2) / tan(FOV / 2) < 8.5; 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: -37 < f123 / f4567 < -5.

5.

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: 1.3 < f1 / f < 5.5; the curvature radius R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: 0.85 < R1 / f < 1.6; the curvature radius R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: 2 < R2 / f < 5.

8.

6. 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: -1.7 < f3 / f < -0.6; the curvature radius R5 of the object side of the third lens and the effective focal length f of the optical lens satisfy: -4 < R5 / f < -1.3; the curvature radius R6 of the image side of the third lens and the effective focal length f of the optical lens satisfy: 0.4 < R6 / f < 3.

7. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.4 < f4 / f < 0.7; the object-side curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: 0.6 < R7 / f < 0.8; the image-side curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -0.65 < R8 / f < -0.

3.

8. 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: -2 < f5 / f < -0.9; 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 < -0.3; the image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -1.2 < R10 / f < -0.

6.

9. The optical lens according to claim 1, wherein The focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -0.9 < f7 / f < -0.5; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.1 < R13 / f < -0.

4.

10. 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: -0.5 < (R9 - R10) / (R9 + R10) < -0.1; 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) < 0.5.

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