Optical lens

Abstract

The present invention provides an optical lens, which comprises, in order from the object side to the imaging surface along the optical axis: a first lens with positive optical power, whose object side surface is convex and whose image side surface is concave; a second lens with negative optical power, whose object side surface is convex and whose image side surface is concave; a third lens with positive optical power, whose object side surface is convex and whose image side surface is concave; a fourth lens with negative optical power, whose object side surface is concave and whose image side surface is convex; a fifth lens with negative optical power, whose object side surface is concave and whose image side surface is concave at the near optical axis; a sixth lens with positive optical power, whose object side surface is convex at the near optical axis and whose image side surface is concave at the near optical axis; a seventh lens with positive optical power, whose object side surface is convex at the near optical axis and whose image side surface is convex at the near optical axis; an eighth lens with negative optical power, whose object side surface is concave at the near optical axis and whose image side surface is convex at the near optical axis.

Description

Technical Field

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

[0002] With the rapid development of smartphone technology, consumers' demands for mobile phone camera performance are constantly increasing. Large aperture and large image area can bring more light and better image quality. At the same time, in order to make the mobile phone portable and beautiful, the imaging lens must also have a thin and short appearance, which makes the lens design more difficult. How to achieve the requirements of large aperture and high pixel at the same time while keeping the lens small is also a difficulty in lens design at this stage. Summary of the invention

[0003] In view of the above problems, an object of the present invention is to provide an optical lens having the advantage of excellent imaging quality.

[0004] The technical solution adopted by the present invention is:

[0005] An optical lens, composed of eight lenses with optical power, including the following in order from the object side to the imaging surface along the optical axis:

[0006] The first lens has positive refractive power, its object side surface is convex, and its image side surface is concave;

[0007] The second lens has a negative optical power, its object side surface is convex, and its image side surface is concave;

[0008] The third lens has positive refractive power, its object side surface is convex, and its image side surface is concave;

[0009] a fourth lens having negative optical power, whose object side surface is concave and whose image side surface is convex;

[0010] A fifth lens element with negative optical power, whose object side surface is concave and whose image side surface is concave near the optical axis;

[0011] a sixth lens having positive refractive power, whose object side surface is convex at the near optical axis and whose image side surface is concave at the near optical axis;

[0012] The seventh lens element has positive refractive power, and its object side surface is convex at the near optical axis, and its image side surface is convex at the near optical axis;

[0013] An eighth lens having negative optical power, whose object side surface is concave at the near optical axis and whose image side surface is convex at the near optical axis;

[0014] The object side surface curvature radius R13 of the seventh lens and the image side surface curvature radius R14 of the seventh lens satisfy: -1<(R13+R14) / (R13-R14)<-0.5.

[0015] More preferably, the true image height IH corresponding to the maximum field of view angle of the optical lens, the effective focal length f of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 1 < (IH / 2) / (f×Tan(FOV / 2)) < 1.03; the true image height IH corresponding to the maximum field of view angle of the optical lens and the back focal length BFL of the optical lens satisfy: 14.5 < IH / BFL < 15.5.

[0016] More preferably, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 7 < f3 / f < 7.5; the central thickness CT3 of the third lens and the edge thickness ET3 of the third lens satisfy: 0.98 < CT3 / ET3 < 1.02.

[0017] More preferably, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -39 < f5 / f < -24; the object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: -75 < R9 / f < -25; the image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: 26 < R10 / f < 34.

[0018] More preferably, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -0.7 < f8 / f < -0.6; the image-side clear aperture radius d16 of the eighth lens and the central thickness CT8 of the eighth lens satisfy: 9.8 < d16 / CT8 < 11.5.

[0019] More preferably, the combined focal length f12 of the first lens and the second lens and the combined focal length f34 of the third lens and the fourth lens satisfy: -0.3 < f12 / f34 < -0.1; the combined focal length f56 of the fifth lens and the sixth lens and the combined focal length f78 of the seventh lens and the eighth lens satisfy: -1.5 < f56 / f78 < -1.1.

[0020] More preferably, the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -1.9 < f7 / f8 < -1.6; the image-side curvature radius R14 of the seventh lens and the object-side curvature radius R15 of the eighth lens satisfy: 15 < R14 / R15 < 302.

[0021] More preferably, the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.9 < IH / f < 2; the overall 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: 0.55 < TTL / IH < 0.65.

[0022] More preferably, the radius of curvature R14 of the image side surface of the seventh lens and the focal length f7 of the seventh lens satisfy: -82.3 < R14 / f7 < -4.4; the radius of curvature R16 of the image side surface of the eighth lens and the focal length f8 of the eighth lens satisfy: 3.5 < R16 / f8 < 6.3.

[0023] More preferably, 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: -0.9 < (R15 - R16) / (R15 + R16) < -0.7; the radius of curvature R13 of the object side surface of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy: -1 < (R13 + R14) / (R13 - R14) < -0.75.

[0024] Compared with the prior art, the optical lens provided by the present invention has one or more advantages such as miniaturization, large image plane, large aperture, and high pixel through specific surface shape settings and reasonable optical power distribution. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0028] Figure 3 It is a graph of axial aberration of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 4 It is a graph of lateral chromatic aberration of the optical lens in Embodiment 1 of the present invention.

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

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

[0032] Figure 7 It is a graph of axial aberration of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 8 It is a graph of lateral chromatic aberration of the optical lens in Embodiment 2 of the present invention.

[0034] Fig. 9 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0035] Fig.10 Graph showing the F-Tan (Theta) distortion of the optical lens in Example 3 of the present invention.

[0036] Fig.11 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0037] Fig.12 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0038] Fig.13 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

[0039] Fig.14 4 is a F-Tan (Theta) distortion curve of the optical lens in Example 4 of the present invention.

[0040] Fig.15 4 is an axial aberration curve diagram of the optical lens in Example 4 of the present invention.

[0041] Fig.16 Graph showing the vertical axis chromatic aberration of the optical lens in Example 4 of the present invention.

[0042] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0043] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application, and are not intended to 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.

[0044] It should be noted that in this specification, the expressions of 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 teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0045] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. 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 shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0046] 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 is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0047] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate 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 expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0048] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0049] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0050] The optical lens provided by the embodiment of the present invention comprises eight lenses in total, which include, 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.

[0051] In some embodiments, the first lens may have a positive focal power, its object side may be convex, and its image side may be concave. The second lens may have a negative focal power, its object side may be convex, and its image side may be concave. The third lens may have a positive focal power, its object side may be convex, and its image side may be concave. The fourth lens may have a negative focal power, its object side may be concave, and its image side may be convex. The fifth lens may have a negative focal power, its object side may be concave, and its image side may be concave near the optical axis. The sixth lens may have a positive focal power, its object side may be convex near the optical axis, and its image side may be concave near the optical axis. The seventh lens may have a positive focal power, its object side may be convex near the optical axis, and its image side may be convex near the optical axis. The eighth lens may have a negative focal power, its object side may be concave near the optical axis, and its image side may be convex near the optical axis.

[0052] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the object side and the first lens. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the image formation.

[0053] In some embodiments, the optical lens may further include a filter, and the filter may be 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.

[0054] In some embodiments, the radius of curvature R13 of the object side of the seventh lens and the radius of curvature R14 of the image side of the seventh lens satisfy: -1 < (R13 + R14) / (R13 - R14) < -0.5. By satisfying the above range and reasonably defining the shapes of the object side and the image side of the seventh lens, the seventh lens can be controlled to have an appropriate surface shape, and the aberration of the optical lens can be effectively corrected. More specifically: -1 < (R13 + R14) / (R13 - R14) < -0.75.

[0055] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens, the effective focal length f of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 1 < (IH / 2) / (f × Tan(FOV / 2)) < 1.03; the true image height IH corresponding to the maximum field of view angle of the optical lens and the back focal length BFL of the optical lens satisfy: 14.5 < IH / BFL < 15.5. By satisfying the above range and reasonably restricting the relationship between the focal length, the field of view angle, and the image height of the optical lens, the size of the distortion can be controlled. At the same time, by reasonably restricting the ratio of the image height to the back focal length, the optical lens can have an appropriate back focus and a large target surface characteristic, and can be matched with a large-size chip. More specifically: 1.01 < (IH / 2) / (f × Tan(FOV / 2)) < 1.03; 14.97 < IH / BFL < 15.31.

[0056] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 7 < f3 / f < 7.5; the central thickness CT3 of the third lens and the edge thickness ET3 of the third lens satisfy: 0.98 < CT3 / ET3 < 1.02. Meeting the above ranges can endow the third lens with an appropriate positive optical power, which is conducive to the smooth transition of the light path and reduces the system sensitivity. At the same time, reasonably controlling the ratio of the thickness to the thinness of the third lens can avoid the phenomenon of air entrapment in the middle area of the lens caused by slow plastic filling at the edge of the lens due to too large a ratio of the thickness to the thinness of the lens during the molding process, resulting in internal bubbles in the final product and affecting the appearance and imaging effect. More specifically: 7.08 < f3 / f < 7.32.

[0057] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -39 < f5 / f < -24; the object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: -75 < R9 / f < -25; the image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: 26 < R10 / f < 34. Meeting the above ranges endows the fifth lens with an appropriate negative optical power and reasonably controls the surface shape of the fifth lens, which is conducive to sharing the negative optical power of the fourth lens, enabling the light to transition smoothly while reducing the tolerance sensitivity of the fourth lens. More specifically: -38.31 < f5 / f < -24.41; -72.05 < R9 / f < -27.28; 26.05 < R10 / f < 33.55.

[0058] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -0.7 < f8 / f < -0.6; the image-side clear aperture radius d16 of the eighth lens and the central thickness CT8 of the eighth lens satisfy: 9.8 < d16 / CT8 < 11.5. Meeting the above ranges can endow the eighth lens with a negative optical power, which is conducive to increasing the imaging area of the optical lens and improving the imaging quality of the optical lens. At the same time, reasonably configuring the ratio of the image-side clear aperture radius to the central thickness of the eighth lens can reduce the total height of the optical system and make the structure of the optical system more compact while meeting the processability requirements of the eighth lens, thereby reducing the volume of the optical system and also being conducive to increasing the aperture of the optical system. More specifically: -0.66 < f8 / f < -0.6; 9.88 < d16 / CT8 < 11.44.

[0059] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f34 of the third lens and the fourth lens satisfy: -0.3 < f12 / f34 < -0.1; the combined focal length f56 of the fifth lens and the sixth lens and the combined focal length f78 of the seventh lens and the eighth lens satisfy: -1.5 < f56 / f78 < -1.1. By satisfying the above ranges and reasonably setting the power distribution of each lens, reasonable deflection of light rays in different fields of view can be achieved, point-to-point imaging can be realized, which is beneficial to the matching between the lens group and the electronic photosensitive chip. At the same time, various aberrations can be effectively corrected, and the resolution of the system can be improved. More specifically: -0.21 < f12 / f34 < -0.17; -1.41 < f56 / f78 < -1.17.

[0060] In some embodiments, the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -1.9 < f7 / f8 < -1.6; the radius of curvature R14 of the image side surface of the seventh lens and the radius of curvature R15 of the object side surface of the eighth lens satisfy: 15 < R14 / R15 < 302. By satisfying the above ranges and reasonably controlling the ratio of the focal length of the seventh lens to the focal length of the eighth lens, it is beneficial to achieve a large image plane while shortening the overall length. At the same time, reasonably controlling the shapes of the image side surface of the seventh lens and the object side surface of the eighth lens is beneficial to correcting distortion and improving the overall imaging quality. More specifically: -1.79 < f7 / f8 < -1.7; 15.83 < R14 / R15 < 301.93.

[0061] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.9 < IH / f < 2.0. By satisfying the above conditions, both the wide-angle characteristic can be achieved to meet the large-range shooting requirements, and the large image plane characteristic can be achieved to improve the imaging quality of the optical lens. More specifically: 1.94 < IH / f < 1.97.

[0062] In some embodiments, 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: 0.55 < TTL / IH < 0.65. By satisfying the above ranges, it is beneficial to achieve a reasonable balance between the short overall length and the large image plane of the lens. More specifically: 0.59 < TTL / IH < 0.62.

[0063] In some embodiments, the radius of curvature R14 of the image side surface of the seventh lens and the focal length f7 of the seventh lens satisfy: -82.3 < R14 / f7 < -4.4; the radius of curvature R16 of the image side surface of the eighth lens and the focal length f8 of the eighth lens satisfy: 3.5 < R16 / f8 < 6.3. Satisfying the above ranges can control the astigmatism and coma of the seventh lens and the eighth lens within a reasonable range, and can effectively balance the astigmatism and coma left by the previous lenses, so that the lens has better imaging quality. More specifically: -82.27 < R14 / f7 < -4.44; 3.54 < R16 / f8 < 6.26.

[0064] 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: -0.9 < (R15 - R16) / (R15 + R16) < -0.7. Satisfying the above range is beneficial to correcting various aberrations of the optical lens, improving the relative illumination of the edge field of view, and enhancing the imaging quality of the optical lens. More specifically: -0.86 < (R15 - R16) / (R15 + R16) < -0.76.

[0065] In some embodiments, the radius of curvature R14 of the image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -91.3 < R14 / f < -4.8; the radius of curvature R16 of the image side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -3.9 < R16 / f < -2.2. Satisfying the above ranges and reasonably setting the ratios of the image side surfaces of the seventh lens and the eighth lens to the focal length of the optical lens respectively can prevent the seventh lens and the eighth lens from being too curved, which is beneficial to reducing the lens processing difficulty and reducing the field curvature and distortion. More specifically: -91.29 < R14 / f < -4.85; -3.85 < R16 / f < -2.29.

[0066] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.1 < TTL / f < 1.3. Satisfying the above range can effectively limit the length of the lens and is beneficial to reducing the volume of the optical lens. More specifically: 1.17 < TTL / f < 1.19.

[0067] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: 0.8 < f1 / f < 0.9. Satisfying the above range can make the first lens have a large positive refractive power, which is beneficial to converging the light incident on the optical lens from the first lens to a large extent, and facilitating the realization of a large field of view angle and a large aperture of the optical lens. More specifically: 0.82 < f1 / f < 0.84.

[0068] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -1.9 < f2 / f < -1.8. Meeting the above range can diverge the light entering the system to a certain extent, which is beneficial to avoiding excessive light deflection caused by the over-concentration of the optical power of the first lens and reducing the difficulty of correcting the aberrations of the rear-end system. More specifically: -1.88 < f2 / f < -1.85.

[0069] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: -3.6 < f4 / f < -3.2. Meeting the above range is beneficial to diverging the light converged by the third lens, balancing the aberrations of the optical lens, and improving the imaging quality of the optical lens. More specifically: -3.59 < f4 / f < -3.35.

[0070] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 3.3 < f6 / f < 3.7. Meeting the above range is beneficial to the smooth transition of light, balancing the aberrations of the optical lens, and improving the imaging quality of the optical lens. More specifically: 3.37 < f6 / f < 3.7.

[0071] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1 < f7 / f < 1.2. Meeting the above range is beneficial to converging the diverging light to the rear-end optical system, which can effectively shorten the total length and improve the resolution quality at the same time. More specifically: 1.08 < f7 / f < 1.14.

[0072] In some embodiments, the object-side curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: -1 < R7 / f < -0.9; the image-side curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -1.8 < R8 / f < -1.5. Meeting the above range enables the fourth lens to adopt a combination of concave and convex surfaces, and at the same time controls the curvature degree of the lens surface of the fourth lens, which can reasonably control various aberrations generated by the fourth lens itself and reduce the tolerance sensitivity of the fourth lens. More specifically: -0.97 < R7 / f < -0.93, -1.68 < R8 / f < -1.6.

[0073] 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: -0.2 < R13 / R14 < 0. Meeting the above range and reasonably setting the lens surface of the seventh lens are beneficial to balancing various aberrations, and at the same time are also beneficial to better converging light and reducing the total length of the optical lens. More specifically: -0.15 < R13 / R14 < 0.

[0074] 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 < R15 / R16 < 0.2. Meeting the above range is conducive to diverging the incident light, causing the peripheral light and the central light to turn upwards, reaching a higher imaging position, better realizing the large target surface imaging of the lens, and improving the imaging quality. More specifically: 0.07 < R15 / R16 < 0.14.

[0075] In some embodiments, the radius of curvature R6 of the image side surface of the third lens and the radius of curvature R7 of the object side surface of the fourth lens satisfy: 2.7 < (R6 - R7) / (R6 + R7) < 2.9. Meeting the above range can reasonably control the shapes of the image side surface of the third lens and the object side surface of the fourth lens, which is conducive to the aberration balance of the third lens itself, thereby reducing the difficulty of aberration correction of the rear-end optical system. More specifically: 2.78 < (R6 - R7) / (R6 + R7) < 2.85.

[0076] In some embodiments, the radius of curvature R9 of the object side surface of the fifth lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: 2.3 < (R9 - R10) / (R9 + R10) < 43.5. Meeting the above range can control the fifth lens to have an appropriate surface shape, which helps to control the light trend of the edge field of view and improve the imaging quality of the edge field of view. More specifically: 2.37 < (R9 - R10) / (R9 + R10) < 43.42.

[0077] In some embodiments, the sagittal height Sag14 of the image side surface clear aperture of the seventh lens and the image side surface clear aperture d14 of the seventh lens satisfy: -0.3 < Sag14 / d14 < -0.2; the sagittal height Sag16 of the image side surface clear aperture of the eighth lens and the image side surface clear aperture d16 of the eighth lens satisfy: -0.4 < Sag16 / d16 < -0.2. Meeting the above range is conducive to the processing and forming of the lens. More specifically: -0.26 < Sag14 / d14 < -0.22, -0.32 < Sag16 / d16 < -0.26.

[0078] In some embodiments, the optical lens satisfies the following conditional expressions: 8.6 mm < f < 8.8 mm; 4.8 mm < EPD < 4.9 mm; 10.2 mm < TTL < 10.4 mm; 1.6 < Fno < 1.9; 1.1 mm < BFL < 1.2 mm; 87° < FOV < 89°; 16 mm < IH < 18 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 overall 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, 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 miniaturization, large image plane, large aperture, and high pixel count. More specifically: 8.68 mm < f < 8.76 mm; 4.82 mm < EPD < 4.87 mm; 10.29 mm < TTL < 10.36 mm; 1.79 < Fno < 1.81; 1.11 mm < BFL < 1.15 mm; 87.59° < FOV < 88.01°; 16.98 mm < IH < 17.21 mm.

[0079] 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, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The optical lens provided by the present invention can adopt an all-plastic lens structure, which can make the structure of the lens relatively compact, and can better achieve the balance of lens miniaturization and high image quality, and reduce costs.

[0080] 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 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 lens miniaturization. More specifically, 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 of the present invention all adopt aspherical lenses.

[0081] In each embodiment of the present invention, when the lens adopts an aspherical lens, the surface shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0082] ;

[0083] Among them, z is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height of h along the optical axis, c is the curvature of the vertex of the surface, K is the quadratic surface coefficient, B, C, D, E, F, G, H, I, and J are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, sixteenth-order, eighteenth-order, and twentieth-order surface coefficients respectively.

[0084] The present invention is further described below in multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different. For specific differences, please refer to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any other changes, substitutions, combinations or simplifications that do not deviate 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.

[0085] Example 1

[0086] See also Figure 1 , shown is a schematic diagram of the structure of the optical lens 100 provided in Example 1 of the present invention, and the optical lens 100 includes, from the object side to the imaging surface along the optical axis, an aperture ST, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G1.

[0087] The first lens L1 has positive refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0088] The second lens L2 has negative refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave;

[0089] The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is concave;

[0090] The fourth lens L4 has negative refractive power, its object-side surface S7 is concave, and its image-side surface S8 is convex;

[0091] The fifth lens L5 has negative refractive power, its object side surface S9 is concave, and its image side surface S10 is concave at the near optical axis;

[0092] The sixth lens L6 has positive refractive power, an object-side surface S11 thereof is convex at the near optical axis, and an image-side surface S12 thereof is concave at the near optical axis;

[0093] The seventh lens L7 has positive refractive power, an object-side surface S13 thereof is convex at the near optical axis, and an image-side surface S14 thereof is convex at the near optical axis;

[0094] The eighth lens L8 has negative refractive power, an object-side surface S15 thereof is concave at the near optical axis, and an image-side surface S16 thereof is convex at the near optical axis;

[0095] The object side surface S17 and the image side surface S18 of the filter G1 are both planes;

[0096] The imaging surface S19 is a plane.

[0097] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 are all plastic aspherical lenses.

[0098] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0099] Table 1-1

[0100]

[0101] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0102] Table 1-2

[0103]

[0104] In this embodiment, the F-Tan (Theta) distortion curve, the axial aberration curve, and the vertical axis chromatic aberration curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 shown.

[0105] Figure 2 The F-Tan (Theta) distortion curve of Example 1 is shown, which represents the F-Tan (Theta) distortion 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 half field angle (unit: °). It can be seen from the figure that the F-Tan (Theta) distortion of the optical lens 100 is controlled within 0%~2%, indicating that the distortion of the optical lens 100 is well corrected.

[0106] Figure 3 The axial aberration curve of Example 1 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the offset of the axial aberration is controlled within -0.04mm~0.03mm, indicating that the optical lens can correct the axial aberration well.

[0107] Figure 4The vertical chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.555 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens can perfectly correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0108] Example 2

[0109] See also Figure 5 , shown is a schematic diagram of the structure of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0110] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0111] Table 2-1

[0112]

[0113] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0114] Table 2-2

[0115]

[0116] In this embodiment, the F-Tan (Theta) distortion curve, the axial aberration curve, and the vertical axis chromatic aberration curve of the optical lens 200 are respectively as follows: Figure 6 , Figure 7 , Figure 8 shown.

[0117] from Figure 6 It can be seen that the F-Tan (Theta) distortion of the optical lens 200 is controlled within 0%~2%, indicating that the distortion of the optical lens 200 is well corrected.

[0118] from Figure 7 It can be seen that the offset of the axial aberration is controlled within ±0.03 mm, indicating that the optical lens 200 can correct the axial aberration well.

[0119] from Figure 8 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2μm~3μm, indicating that the optical lens 200 can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0120] Example 3

[0121] See also Fig. 9 , shown is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0122] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0123] Table 3-1

[0124]

[0125] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0126] Table 3-2

[0127]

[0128] In this embodiment, the F-Tan (Theta) distortion curve, the axial aberration curve, and the vertical axis chromatic aberration curve of the optical lens 300 are respectively as follows: Fig.10 , Fig.11 , Fig.12 shown.

[0129] from Fig.10 It can be seen that the F-Tan (Theta) distortion of the optical lens 300 is controlled within 0%~2%, indicating that the distortion of the optical lens 300 is well corrected.

[0130] from Fig.11 It can be seen that the offset of the axial aberration is controlled within ±0.03 mm, indicating that the optical lens 300 can correct the axial aberration well.

[0131] from Fig.12 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2.5μm, indicating that the optical lens 300 can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0132] Example 4

[0133] See also Fig.13 , shown is a schematic diagram of the structure of an optical lens 400 provided in Example 4 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0134] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0135] Table 4-1

[0136]

[0137] The surface parameters of the aspherical lens of the optical lens in Example 4 are shown in Table 4-2.

[0138] Table 4-2

[0139]

[0140] In this embodiment, the F-Tan (Theta) distortion curve, the axial aberration curve, and the vertical chromatic aberration curve of the optical lens 400 are respectively as follows: Fig.14 , Fig.15 , Fig.16 shown.

[0141] from Fig.14 It can be seen that the F-Tan (Theta) distortion of the optical lens 400 is controlled within 0%~2%, indicating that the distortion of the optical lens 400 is well corrected.

[0142] from Fig.15 It can be seen that the offset of the axial aberration is controlled within -0.03mm~0.04mm, which means that the optical lens 400 can correct the axial aberration well.

[0143] from Fig.16 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -3μm~2μm, indicating that the optical lens 400 can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0144] Please refer to Table 5-1 and Table 5-2, which are the optical characteristics corresponding to the above-mentioned embodiments, including the effective focal length f of the optical lens, the maximum field of view FOV, the entrance pupil diameter EPD, the total optical length TTL, the aperture value Fno, the real image height IH corresponding to the maximum field of view, the back focal length BFL and the numerical value corresponding to each conditional expression in each embodiment.

[0145] Table 5-1

[0146]

[0147] Table 5-2

[0148]

[0149] In summary of the above embodiments, the optical lens provided by the present invention uses eight lenses with specific optical power and specific surface shape, so that the lens has one or more advantages such as miniaturization, large image surface, large aperture, high pixel, etc.

[0150] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0151] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which 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 attached claims.

Claims

1. An optical lens is composed of eight lenses with optical power, and sequentially 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 negative optical power, whose object side is convex and whose image side is concave; A third lens with positive optical power, whose object side is convex and whose image side is concave; A fourth lens with negative optical power, whose object side is concave and whose image side is convex; A fifth lens with negative optical power, whose object side is concave and whose image side is concave near the optical axis; A sixth lens with positive optical power, whose object side is convex near the optical axis and whose image side is concave near the optical axis; A seventh lens with positive optical power, whose object side is convex near the optical axis and whose image side is convex near the optical axis; An eighth lens with negative optical power, whose object side is concave near the optical axis and whose image side is convex near the optical axis; Wherein, the radius of curvature R13 of the object side of the seventh lens and the radius of curvature R14 of the image side of the seventh lens satisfy: -1 < (R13 + R14) / (R13 - R14) < -0.5; the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.9 < IH / f < 2.

2. The optical lens according to claim 1, characterized in that: The true image height IH corresponding to the maximum field of view angle of the optical lens, the effective focal length f of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 1 < (IH / 2) / (f × Tan(FOV / 2)) < 1.03; the true image height IH corresponding to the maximum field of view angle of the optical lens and the back focal length BFL of the optical lens satisfy: 14.5 < IH / BFL < 15.

5.

3. The optical lens according to claim 1, characterized in that: The focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 7 < f3 / f < 7.5; the central thickness CT3 of the third lens and the edge thickness ET3 of the third lens satisfy: 0.98 < CT3 / ET3 < 1.

02.

4. The optical lens according to claim 1, characterized in that: The focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -39 < f5 / f < -24; the radius of curvature R9 of the object side of the fifth lens and the effective focal length f of the optical lens satisfy: -75 < R9 / f < -25; the radius of curvature R10 of the image side of the fifth lens and the effective focal length f of the optical lens satisfy: 26 < R10 / f < 34.

5. The optical lens according to claim 1, characterized in that: The focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -0.7 < f8 / f < -0.6; the clear aperture radius d16 of the image side of the eighth lens and the central thickness CT8 of the eighth lens satisfy: 9.8 < d16 / CT8 < 11.

5.

6. The optical lens according to claim 1, characterized in that: The combined focal length f12 of the first lens and the second lens and the combined focal length f34 of the third lens and the fourth lens satisfy: -0.3 < f12 / f34 < -0.1; the combined focal length f56 of the fifth lens and the sixth lens and the combined focal length f78 of the seventh lens and the eighth lens satisfy: -1.5 < f56 / f78 < -1.

1.

7. The optical lens according to claim 1, characterized in that: The focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -1.9 < f7 / f8 < -1.6; the image-side curvature radius R14 of the seventh lens and the object-side curvature radius R15 of the eighth lens satisfy: 15 < R14 / R15 < 302.

8. The optical lens according to claim 1, characterized in that: The true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.94 < IH / f < 1.97, and the overall 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: 0.55 < TTL / IH < 0.

65.

9. The optical lens according to claim 1, characterized in that: The image-side curvature radius R14 of the seventh lens and the focal length f7 of the seventh lens satisfy: -82.3 < R14 / f7 < -4.4; the image-side curvature radius R16 of the eighth lens and the focal length f8 of the eighth lens satisfy: 3.5 < R16 / f8 < 6.

3.

10. The optical lens according to claim 1, characterized in that: The object-side curvature radius R15 of the eighth lens and the image-side curvature radius R16 of the eighth lens satisfy: -0.9 < (R15 - R16) / (R15 + R16) < -0.7; the object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -1 < (R13 + R14) / (R13 - R14) < -0.75.

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