Optical lens

Abstract

The present invention provides an optical lens, which has a total of eight lenses. Along the optical axis from the object side to the imaging surface, it successively includes: a first lens with a negative focal power, whose object side surface is convex and whose image side surface is concave; a second lens with a negative focal power, whose object side surface is concave and whose image side surface is convex; a third lens with a positive focal power, whose object side surface is convex and whose image side surface is concave; a fourth lens with a negative focal power, whose object side surface and image side surface are both concave; a fifth lens with a positive focal power, whose object side surface is convex; a sixth lens with a positive focal power, whose image side surface is convex; a seventh lens with a negative focal power, whose object side surface and image side surface are both concave; an eighth lens with a positive focal power, whose object side surface is convex and whose image side surface is concave. The optical lens provided by the present invention has one or more advantages such as a large field of view angle, a large image surface, a large aperture, and high imaging quality through specific surface shape matching and reasonable focal power distribution.

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 eight lenses, which in turn include from the object side to the imaging surface along the optical axis:

[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, and the image side surface thereof is concave;

[0010] A fourth lens with negative optical power, the object side surface thereof is concave, and the image side surface thereof is concave;

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

[0012] A sixth lens with positive optical power, the image side surface thereof is convex;

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

[0014] An eighth lens with positive optical power, the object side surface thereof is convex, and the image side surface thereof is concave;

[0015] Among them, the image-side curvature radius R10 of the fifth lens and the object-side curvature radius R11 of the sixth lens satisfy: 0.6 < |(R10 - R11) / (R10 + R11)| < 0.85.

[0016] Further preferably, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 8 < TTL / f < 9.9; the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3.5 < TTL / IH < 4.4.

[0017] Further preferably, the maximum field of view angle FOV of the optical lens and the f-number Fno of the optical lens satisfy: 84° < FOV / Fno < 89°; 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: 3.8 < IH / EPD < 4.4.

[0018] Further 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 < 2.5; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.7 < BFL / f < 1.3.

[0019] Further preferably, the overall optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 16 < TTL / (IH / 2) / (FOV / 2)×180° < 20; the object-side clear aperture d1 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: 0.25 < d1 / (IH / 2) / tan(FOV / 2) < 0.5.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.7 < f5 / f < 3.9; the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.6 < f6 / f < 3.6; the combined focal length f1234 of the combination lens of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the combination of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -7.2 < f1234 / f5678 < -2.3.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -1.85 < f7 / f < -1.1; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.6 < R13 / f < -0.95; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 3.1 < R14 / f < 9.

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 2.9 < f8 / f < 4.3; the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.3 < R15 / f < 1.9; the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 7.1 < R16 / f < 21.

[0023] Further preferably, the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: 0.45 < f5 / f6 < 2.25; the image-side curvature radius R10 of the fifth lens and the object-side curvature radius R11 of the sixth lens satisfy: 0.2 < R10 / R11 < 11.

[0024] Further preferably, the object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -0.74 < (R13 + R14) / (R13 - R14) < -0.4; the object-side curvature radius R15 of the eighth lens and the image-side curvature radius R16 of the eighth lens satisfy: -0.84 < (R15 - R16) / (R15 + R16) < -0.61.

[0025] The optical lens provided by the present invention adopts eight 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 enable the lens to have one or more advantages such as a large field of view, a large image plane, a large aperture, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 2 is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 3 It is the MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 4 It is the structural schematic diagram of the optical lens in Embodiment 2 of the present invention.

[0031] Figure 5 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 6 It is the MTF curve graph of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 7 It is the structural schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0034] Figure 8 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0035] Figure 9 It is the MTF curve graph of the optical lens in Embodiment 3 of the present invention.

[0036] Figure 10 It is the structural schematic diagram of the optical lens in Embodiment 4 of the present invention.

[0037] Figure 11 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 4 of the present invention.

[0038] Figure 12 It is the MTF curve graph of the optical lens in Embodiment 4 of the present invention.

[0039] Figure 13 It is the structural schematic diagram of the optical lens in Embodiment 5 of the present invention.

[0040] Figure 14 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 5 of the present invention.

[0041] Figure 15 It is the MTF curve graph of the optical lens in Embodiment 5 of the present invention.

[0042] Figure 16 It is the structural schematic diagram of the optical lens in Embodiment 6 of the present invention.

[0043] Figure 17 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 6 of the present invention.

[0044] Figure 18 It is the MTF curve graph of the optical lens in Embodiment 6 of the present invention.

[0045] Figure 19 This is a schematic structural diagram of the optical lens in Embodiment 7 of the present invention.

[0046] Figure 20 This is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 7 of the present invention.

[0047] Figure 21 This is the MTF curve graph of the optical lens in Embodiment 7 of the present invention.

[0048] Figure 22 This is a schematic structural diagram of the optical lens in Embodiment 8 of the present invention.

[0049] Figure 23 This is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 8 of the present invention.

[0050] Figure 24 This is the MTF curve graph of the optical lens in Embodiment 8 of the present invention.

[0051] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0052] To better understand the present application, more detailed descriptions of various aspects of the present application will be made 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.

[0053] 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 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.

[0054] In the drawings, for the sake of convenience of illustration, the thickness, size and shape of the lens have been slightly exaggerated. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces 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.

[0055] 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 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.

[0056] It should also be understood that the terms "comprising", "comprising of", "having", "containing" and / or "containing of", 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 the list of listed features, it modifies the entire list of listed features, rather than individual elements in the list. In addition, when describing the embodiments of the present 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.

[0057] 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.

[0058] 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.

[0059] The optical lens provided by the embodiment of the present invention has a total of eight 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, a seventh lens and an eighth lens.

[0060] In some embodiments, the first lens may have a negative focal power, with its object side being convex and its image side being concave. The second lens may have a negative focal power, with its object side being concave and its image side being convex. The third lens may have a positive focal power, with its object side being convex and its image side being concave. The fourth lens may have a negative focal power, with its object side being concave and its image side being concave. The fifth lens may have a positive focal power, with its object side being convex and its image side may be concave or convex. The sixth lens has a positive focal power, with its object side may be concave or convex and its image side being convex. The seventh lens may have a negative focal power, with its object side being concave and its image side being concave. The eighth lens may have a positive focal power, with its object side being convex and its image side being concave.

[0061] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the fourth lens and the fifth lens. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the imaging. In addition, when the diaphragm is located between the fourth lens and the fifth lens, the diaphragm can reasonably distribute the functions of the first lens to the eighth lens. For example, the first lens, the second lens, the third lens, and the fourth lens can be used to receive light to a greater extent, and the fifth lens to the eighth lens can be used to correct aberrations, which is beneficial to balancing the structure of the entire optical system. In addition, when the diaphragm is located between the fourth lens and the fifth lens, it is convenient to correct the diaphragm aberration.

[0062] In some embodiments, the optical lens may further include a filter, and the filter is disposed between the eighth 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.

[0063] In some embodiments, the sixth lens and the seventh 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 technology difficulty of the optical lens and improving the assembly yield of the optical lens.

[0064] In some embodiments, the radius of curvature R10 of the image side of the fifth lens and the radius of curvature R11 of the object side of the sixth lens satisfy: 0.6 < |(R10 - R11) / (R10 + R11)| < 0.85. Satisfying the above range is beneficial to the smooth transition of light and simultaneously corrects various aberrations of the optical lens, improving the imaging quality of the optical lens.

[0065] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 8 < TTL / f < 9.9. 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, 8.1 < TTL / f < 9.77.

[0066] 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: 3.5 < TTL / IH < 4.4. Meeting the above range ensures that, with the same total length of the lens, a larger image plane is obtained, enabling a larger-sized imaging chip to be matched for high-definition imaging, and better achieving the balance between the small total length and the large image plane of the lens. More specifically, 3.58 < TTL / IH < 4.32.

[0067] In some embodiments, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 84° < FOV / Fno < 89°. Meeting the above range defines that the optical lens has an appropriate field of view angle and aperture value, enabling it to collect light at a large angle and obtain good imaging quality. More specifically, 84.2° < FOV / Fno < 88.25°.

[0068] 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: 3.8 < IH / EPD < 4.4. Meeting the above range can increase the width of the light beam incident on the optical lens, improving the brightness at the image plane of the optical lens and avoiding the generation of vignetting. More specifically, 3.95 < IH / EPD < 4.36.

[0069] 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: 2.1 < IH / f < 2.5. 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, 2.24 < IH / f < 2.43.

[0070] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.7 < BFL / f < 1.3. Meeting the above range defines that the optical lens has an appropriate back focus, facilitating the reasonable arrangement of the positions of each lens and reducing the processing and assembly difficulty. More specifically, 0.71 < BFL / f < 1.125.

[0071] In some embodiments, the total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 16 < TTL / (IH / 2) / (FOV / 2)×180° < 20. Meeting the above range restricts the length of the optical lens under the condition of the same imaging area and the same field of view angle, realizing the miniaturization of the optical lens. More specifically, 16.15 < TTL / (IH / 2) / (FOV / 2)×180° < 19.4.

[0072] 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 angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.25 < d1 / (IH / 2) / tan(FOV / 2) < 0.5. Meeting the above range can make the front aperture small while meeting the requirements of the optical lens having a large field of view angle and a large image plane. More specifically, 0.25 < d1 / (IH / 2) / tan(FOV / 2) < 0.47.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.7 < f5 / f < 3.9; 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: 1.6 < R9 / f < 1.9. Meeting the above range and setting the fifth lens to have a positive refractive power and a suitable surface shape are beneficial to converging light while correcting the field curvature and distortion of the optical lens, and improving the imaging quality of the optical lens. More specifically, 1.73 < f5 / f < 3.84; 1.64 < R9 / f < 1.82.

[0074] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.6 < f6 / f < 3.6. Meeting the above range and defining the sixth lens to have a positive optical power are beneficial to light convergence. And by combining the sixth lens with a positive optical power and the seventh lens with a negative optical power, the optical path difference between different fields of view can be adjusted, the resolution can be improved, it is beneficial for light to enter the rear lens smoothly, and further the field curvature can be reduced and the off-axis aberration of the optical lens can be corrected. More specifically, 1.63 < f6 / f < 3.59.

[0075] In some embodiments, the combined focal length f1234 of the combination lens of the first lens, the second lens, the third lens, and the fourth lens and the combined focal length f5678 of the combination lens of the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy: -7.2 < f1234 / f5678 < -2.3. Meeting the above range and reasonably setting the relationship between the lens groups before and after the aperture are beneficial to various aberrations generated by the optical lens and improve the overall imaging quality. More specifically, -7.11 < f1234 / f5678 < -2.3.

[0076] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -1.85 < f7 / f < -1.1; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.6 < R13 / f < -0.95; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 3.1 < R14 / f < 9. Meeting the above ranges and setting the seventh lens to have a negative refractive power and a biconcave surface shape can effectively balance various aberrations generated by the front lens group. At the same time, it is beneficial to increase the divergence degree of light, increase the area of light entering the imaging surface, achieve large-format imaging of the lens, and improve the imaging quality of the optical lens. More specifically, -1.8 < f7 / f < -1.14; -1.53 < R13 / f < -0.99; 3.19 < R14 / f < 8.91.

[0077] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 2.9 < f8 / f < 4.3; the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.3 < R15 / f < 1.9; the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 7.1 < R16 / f < 21. Meeting the above ranges and setting the eighth lens to have a positive refractive power and a suitable surface shape is beneficial to light convergence, enables the light trend to smoothly transition to the rear, reduces the height of the light incident on the rear, slows down the upward trend of the light, avoids the light energy loss caused by the excessive chief ray angle of the large field-of-view light reaching the imaging surface, is conducive to improving the illuminance of the edge field of view, and is beneficial to achieving a short optical total length. More specifically, 2.99 < f8 / f < 4.22; 1.32 < R15 / f < 1.89; 7.16 < R16 / f < 20.39.

[0078] In some embodiments, the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: 0.45 < f5 / f6 < 2.25; the image-side curvature radius R10 of the fifth lens and the object-side curvature radius R11 of the sixth lens satisfy: 0.2 < R10 / R11 < 11. Meeting the above ranges is beneficial to the smooth transition of light, is beneficial to correcting the aberrations of the optical lens, and improves the imaging quality of the optical lens. More specifically, 0.48 < f5 / f6 < 2.2; 0.2 < R10 / R11 < 10.87.

[0079] In some embodiments, the object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -0.74 < (R13 + R14) / (R13 - R14) < -0.4. Meeting the above range is beneficial to 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.

[0080] In some embodiments, the radius of curvature R15 of the object side surface of the eighth lens and the radius of curvature R16 of the image side surface of the eighth lens satisfy: -0.84 < (R15 - R16) / (R15 + R16) < -0.61. Satisfying the above range is beneficial to suppressing the angle of incidence of the marginal field of view on the imaging surface, effectively transmitting more light beams to the imaging surface, and at the same time being able to balance the field curvature and spherical aberration of the optical lens, improving the imaging quality of the optical lens.

[0081] 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 eighth lens along the optical axis satisfy: 0.5 < ∑CT / TTL < 0.75. Satisfying the above range can effectively compress the total length of the optical lens and is beneficial to the structural design and production process of the optical lens. More specifically, 0.54 < ∑CT / TTL < 0.72.

[0082] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis and the effective focal length f of the optical lens satisfy: 4.5 < ΣCT / f < 7. Satisfying 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, 4.55 < ΣCT / f < 6.93.

[0083] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.2 < f1 / f < -1.7. Satisfying the above range, by setting the first lens to have a negative refractive power, it is beneficial for the first lens to receive light at a larger angle and collect as much light as possible into the rear optical system, increasing the light flux while achieving a large field of view. More specifically, -2.11 < f1 / f < -1.78.

[0084] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -24 < f2 / f < -10. Satisfying the above range makes the second lens have a negative optical power and has the effect of diverging light. At the same field of view angle, the light emerging from the image side surface of the first lens is further diverged, and the central light and marginal light of each field of view can be dispersed, enabling the rear optical system to have a larger light receiving surface to receive the light emerging from the image side surface of the second lens, achieving a larger light input and being beneficial to increasing the relative illumination. More specifically, -23.95 < f2 / f < -10.92.

[0085] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2.9 < f3 / f < 3.5. Meeting the above range defines that the third lens has an appropriate positive optical power, which has the effect of converging light rays, reducing the height of peripheral light rays, and is beneficial to reducing the aperture of the rear lens. More specifically, 2.95 < f3 / f < 3.45.

[0086] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -5 < f4 / f < -4.1; the radius of curvature R8 of the image side of the fourth lens and the effective focal length f of the optical lens satisfy: 3.4 < R8 / f < 5.2. Meeting the above range defines that the fourth lens has an appropriate negative optical power, which can diverge the light rays emitted by the third lens, making the light rays in the edge field of view show an upward trend, which is beneficial to the image points on the imaging surface being 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 of the optical lens. More specifically, -4.97 < f4 / f < -4.19; 3.49 < R8 / f < 5.19.

[0087] In some embodiments, the combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens and the effective focal length f of the optical lens satisfy: -19 < f1234 / f < -5; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens, and the eighth lens and the effective focal length f of the optical lens satisfy: 2.2 < f5678 / f < 2.6. Meeting the above range, the focal length relationship of the lens groups before and after the aperture is beneficial to balancing various aberrations generated by the lens groups before and after the aperture and improving the overall imaging quality. More specifically, -18.22 < f1234 / f < -5.3; 2.26 < f5678 / f < 2.57.

[0088] In some embodiments, the optical lens satisfies the following conditional expressions: 4.6 mm < f < 5 mm; 145° < FOV < 165°; 2.5 mm < EPD < 2.9 mm; 39 mm < TTL < 49 mm; 1.6 < Fno < 2; 11 mm < IH < 11.2 mm; 17 < CRA < 21°; 3.4 mm < BFL < 6.1 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 image plane, a large aperture, and a large field of view angle. More specifically, 4.6 mm < f < 4.96 mm; 2.55 mm < EPD < 2.82 mm; 39.9 mm < TTL < 48.1 mm; 1.69 < Fno < 1.91; 17.38° < CRA < 20.01°; 3.49 mm < BFL < 6.01 mm; 149° < FOV < 161°; 11.12 mm < IH < 11.15 mm.

[0089] 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.

[0090] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth 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 second lens, the fifth lens, and the eighth lens of the present invention adopt aspherical lenses; the first lens, the third lens, the fourth lens, and the seventh lens adopt spherical lenses; the sixth lens can adopt a spherical lens or an aspherical lens.

[0091] 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:

[0092] ;

[0093] 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.

[0094] The present invention will be further described below with multiple embodiments. In each embodiment, the thickness, curvature radius, and material selection of each lens in the optical lens are partially different. For specific differences, refer to the parameter tables of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any 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.

[0095] Embodiment 1

[0096] 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 fourth lens L4, a diaphragm ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a filter G1.

[0097] 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;

[0098] 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;

[0099] The third lens L3 has a positive optical power. Its object side surface S5 and image side surface S6 are both convex surfaces;

[0100] The fourth lens L4 has a negative optical power. Its object side surface S7 is a concave surface, and its image side surface S8 is a concave surface;

[0101] 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;

[0102] The sixth lens L6 has a positive optical power. Its object side surface S11 is a convex surface, and its image side surface is a convex surface;

[0103] The seventh lens L7 has a negative optical power. Its object side surface is a concave surface, and its image side surface S13 is a concave surface;

[0104] The sixth lens L6 and the seventh lens L7 form a cemented lens group with a negative optical power, that is, the cemented surface of the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7 is S12;

[0105] The eighth lens L8 has a positive optical power, its object side S14 is convex, and its image side S15 is concave;

[0106] Both the object side S16 and the image side S17 of the filter are flat;

[0107] The imaging surface S18 is flat.

[0108] The second lens L2, the fifth lens L5, and the eighth lens L8 are made of glass aspherical lenses; the first lens L1, the third lens L3, the fourth lens L4, the sixth lens L6, and the seventh lens L7 are made of glass spherical lenses.

[0109] The relevant parameters of each lens in the optical lens 100 in Embodiment 1 are shown in Table 1.

[0110] Table 1

[0111]

[0112] The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0113] Table 1-2

[0114]

[0115] In this embodiment, the F-Tan(Theta) distortion curve and the MTF curve graph of the optical lens 100 are respectively as Figure 2 , Figure 3 shown.

[0116] 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 half field of view angle (unit: °). It can be seen from the figure that the F-Tan(Theta) distortion of the optical lens is controlled within -70% to 0, indicating that the optical lens can correct distortion well.

[0117] Figure 3 shows the MTF (Modulation Transfer Function) curve graph of Embodiment 1, which represents the modulation degree 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 0.38 in the entire field of view. In the range of 0 to 180 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.

[0118] Example 2

[0119] Please refer to Figure 4 , which shows the structural schematic diagram of the optical lens 200 provided in Embodiment 2 of the present invention. Compared with Embodiment 1, the main difference is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0120] The relevant parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2.

[0121] Table 2

[0122]

[0123] The aspherical lens surface type parameters of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0124] Table 2-2

[0125]

[0126] In this embodiment, the F-Tan(Theta) distortion curve and MTF curve graph of the optical lens 200 are respectively as shown in Figure 5 , Figure 6 shown. It can be seen from Figure 5 that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can better correct the distortion. It can be seen from Figure 6 that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0 to 180 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.

[0127] Example 3

[0128] Please refer to Figure 7 , which shows the structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present invention. Compared with Embodiment 1, the main difference is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0129] The relevant parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3.

[0130] Table 3

[0131]

[0132] The aspherical lens surface type parameters of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0133] Table 3-2

[0134]

[0135] In this embodiment, the F-Tan(Theta) distortion curve and the MTF curve graph of the optical lens 300 are respectively as shown in Figure 8 and Figure 9 shown. It can be seen from Figure 8 that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct the distortion well. It can be seen from Figure 9 that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0 to 180 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.

[0136] Embodiment 4

[0137] Please refer to Figure 10 , which shows the structural schematic diagram of the optical lens 400 provided in Embodiment 4 of the present invention. Compared with Embodiment 1, the main difference is that the optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.

[0138] The relevant parameters of each lens in the optical lens 400 in Embodiment 4 are shown in Table 4.

[0139] Table 4

[0140]

[0141] The aspherical lens surface type parameters of the optical lens 400 in Embodiment 4 are shown in Table 4-2.

[0142] Table 4-2

[0143]

[0144] In this embodiment, the F-Tan(Theta) distortion curve and the MTF curve graph of the optical lens 400 are respectively as shown in Figure 11 and Figure 12 shown. It can be seen from Figure 11 that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct the distortion well. It can be seen from Figure 12 that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0 to 180 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.

[0145] Example 5

[0146] Please refer to Figure 13 , which shows the structural schematic diagram of the optical lens 500 provided in Embodiment 5 of the present invention. Compared with Embodiment 1, the main differences are as follows: The sixth lens L6 and the seventh lens L7 are not a cemented lens group; the sixth lens L6 is a glass aspherical lens; the image side S10 of the fifth lens L5 is convex; the object side S11 of the sixth lens L6 is concave; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0147] The relevant parameters of each lens in the optical lens 500 in Embodiment 5 are shown in Table 5.

[0148] Table 5

[0149]

[0150] The surface type parameters of the aspherical lenses of the optical lens 500 in Embodiment 5 are shown in Table 5-2.

[0151] Table 5-2

[0152]

[0153] In this embodiment, the F-Tan(Theta) distortion curve and MTF curve graph of the optical lens 500 are respectively as shown in Figure 14 , Figure 15 . It can be seen from Figure 14 that the F-Tan(Theta) distortion of the optical lens is controlled within -70% to 0, indicating that the optical lens can correct distortion well. It can be seen from Figure 15 that the MTF value of this embodiment is above 0.45 within the entire field of view. In the range of 0 to 180 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.

[0154] Example 6

[0155] Please refer to Figure 16 , which shows the structural schematic diagram of the optical lens 600 provided in Embodiment 6 of the present invention. Compared with Embodiment 1, the main differences are as follows: The sixth lens L6 and the seventh lens L7 are not a cemented lens group; the sixth lens L6 is a glass aspherical lens; the image side S10 of the fifth lens L5 is convex; the object side S11 of the sixth lens L6 is concave; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0156] The relevant parameters of each lens in the optical lens 600 in Embodiment 6 are shown in Table 6.

[0157] Table 6

[0158]

[0159] The surface type parameters of the aspherical lens of the optical lens 600 in Example 6 are shown in Table 6-2.

[0160] Table 6-2

[0161]

[0162] In this embodiment, the F-Tan(Theta) distortion curve and the MTF curve graph of the optical lens 600 are respectively as Figure 17 , Figure 18 shown. It can be seen from Figure 17 that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct the distortion well. It can be seen from Figure 18 that the MTF value of this embodiment is above 0.48 in the entire field of view. In the range of 0 to 180 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.

[0163] Example 7

[0164] Please refer to Figure 19 , which shows the structural schematic diagram of the optical lens 700 provided in Embodiment 7 of the present invention. Compared with Embodiment 1, the main differences are: the sixth lens L6 and the seventh lens L7 are not a cemented lens group; the sixth lens L6 is made of a glass aspherical lens; the image side S10 of the fifth lens L5 is a convex surface; the object side S11 of the sixth lens L6 is a concave surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0165] The relevant parameters of each lens in the optical lens 700 in Example 7 are shown in Table 7.

[0166] Table 7

[0167]

[0168] The surface type parameters of the aspherical lens of the optical lens 700 in Example 7 are shown in Table 7-2.

[0169] Table 7-2

[0170]

[0171] In this embodiment, the F-Tan(Theta) distortion curve and the MTF curve graph of the optical lens 700 are respectively asFigure 20 , Figure 21 as shown. From Figure 20 it can be seen that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct distortion well. From Figure 21 it can be seen that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0 to 180 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.

[0172] Example 8

[0173] Please refer to Figure 22 , which shows the structural schematic diagram of the optical lens 800 provided in Example 8 of the present invention. Compared with Example 1, the main differences are: the sixth lens L6 and the seventh lens L7 are not a cemented lens group; the sixth lens L6 is a glass aspherical lens; the image side S10 of the fifth lens L5 is a convex surface; the object side S11 of the sixth lens L6 is a concave surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0174] The relevant parameters of each lens in the optical lens 800 in Example 8 are shown in Table 8.

[0175] Table 8

[0176]

[0177] The surface type parameters of the aspherical lens of the optical lens 800 in Example 8 are shown in Table 8-2.

[0178] Table 8-2

[0179]

[0180] In this embodiment, the F-Tan(Theta) distortion curve and MTF curve diagram of the optical lens 800 are respectively as Figure 23 , Figure 24 shown. From Figure 23 it can be seen that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct distortion well. From Figure 24 it can be seen that the MTF value of this embodiment is above 0.5 within the entire field of view. In the range of 0 to 180 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.

[0181] Please refer to Table 9 for the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the f-number 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 expression in each embodiment.

[0182] Table 9

[0183]

[0184] In summary of the above embodiments, the optical lens provided by the present invention uses eight lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power distributions, 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 angle, a large image plane, a large aperture, and high imaging quality.

[0185] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0186] The above-described embodiments merely represent several implementation manners of the present invention. The descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. An optical lens, consisting of eight lenses in total, characterized in that, It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with 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 and whose image side surface is concave; A fourth lens with a negative optical power, whose object side surface is concave and whose image side surface is concave; A fifth lens with a positive optical power, whose object side surface is convex; A sixth lens with a positive optical power, whose image side surface is convex; A seventh lens with a negative optical power, whose object side surface is concave and whose image side surface is concave; An eighth lens with a positive optical power, whose object side surface is convex and whose image side surface is concave; Wherein, the radius of curvature R10 of the image side surface of the fifth lens and the radius of curvature R11 of the object side surface of the sixth lens satisfy: 0.6 < |(R10 - R11) / (R10 + R11)| < 0.

85.

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: 8 < TTL / f < 9.9; 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: 3.5 < TTL / IH < 4.

4.

3. The optical lens according to claim 1, characterized in that, The maximum field of view angle FOV of the optical lens and the f-number Fno of the optical lens satisfy: 84° < FOV / Fno < 89°; 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: 3.8 < IH / EPD < 4.

4.

4. The optical lens according to claim 1, wherein The true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.1 < IH / f < 2.5; The effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.7 < BFL / f < 1.

3.

5. The optical lens according to claim 1, characterized in that, The total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 16 < TTL / (IH / 2) / (FOV / 2)×180° < 20; 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: 0.25 < d1 / (IH / 2) / tan(FOV / 2) < 0.

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 f5 of the fifth lens satisfy: 1.7 < f5 / f < 3.9; The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.6 < f6 / f < 3.6; The combined focal length f1234 of the combination lens of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the combination lens of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -7.2 < f1234 / f5678 < -2.

3.

7. The optical lens according to claim 1, wherein The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -1.85 < f7 / f < -1.1; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.6 < R13 / f < -0.95; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 3.1 < R14 / f < 9.

8. The optical lens according to claim 1, characterized in that The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 2.9 < f8 / f < 4.3; the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.3 < R15 / f < 1.9; the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 7.1 < R16 / f < 21.

9. The optical lens according to claim 1, wherein The focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: 0.45 < f5 / f6 < 2.25; the image-side curvature radius R10 of the fifth lens and the object-side curvature radius R11 of the sixth lens satisfy: 0.2 < R10 / R11 < 11.

10. The optical lens according to claim 1, characterized in that, The object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -0.74 < (R13 + R14) / (R13 - R14) < -0.4; the object-side curvature radius R15 of the eighth lens and the image-side curvature radius R16 of the eighth lens satisfy: -0.84 < (R15 - R16) / (R15 + R16) < -0.61.

Images