Optical lens

Abstract

The invention provides an optical lens, which sequentially comprises a first lens with negative focal power from an object side to an imaging surface along an optical axis, a second lens with negative focal power, a third lens with positive focal power and a fourth lens with negative focal power from the object side to the imaging surface, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a convex surface; the object side surface of the sixth lens is a concave surface, and the image side surface of the sixth lens is a convex surface; wherein the curvature radius R5 of the object side surface of the third lens and the curvature radius R11 of the object side surface of the sixth lens meet the following formula:-0.7 lt; (R5-R11) / (R5 + R11) lt; and-0.2%. The optical lens provided by the invention has the advantage of excellent imaging quality through specific surface shape arrangement 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] In recent years, with the rapid development of the smart home and security monitoring fields, smart surveillance cameras have entered thousands of households, becoming products that help people communicate with their families and record beautiful lives, providing convenience for people's daily lives. As the usage scope and scenarios of smart surveillance cameras increase, people have higher requirements for their performance, pursuing high-definition imaging effects even in extreme environments such as cold or hot, and being able to clearly see the surrounding scenes in low-light environments. However, although the current surveillance lenses on the market perform well in some aspects, there is still room for improvement in some specific technical indicators.

[0003] Therefore, how to make the surveillance lens meet high imaging quality is an urgent problem to be solved at present. Summary of the Invention

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

[0005] The technical solution adopted by the present invention is as follows: An optical lens is composed of six lenses, and successively includes from the object side to the imaging surface along the optical axis: A first lens with negative optical power, whose object side is convex and whose image side is concave; A second lens with negative optical power, whose object side is concave and whose image side is convex; A third lens with positive optical power, whose object side is concave and whose image side is convex; A fourth lens with positive optical power, whose object side is convex and whose image side is convex; A fifth lens with negative optical power, whose object side is concave and whose image side is convex; A sixth lens with positive optical power, whose object side is concave and whose image side is convex; Wherein, the curvature radius R5 of the object side of the third lens and the curvature radius R11 of the object side of the sixth lens satisfy: -0.7 < (R5 - R11) / (R5 + R11) < -0.2.

[0006] Further preferably, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 63° < FOV / Fno < 88°; the true image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.3 < IH / EPD < 3.3.

[0007] 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: 1.4 < IH / f < 2.1; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.9 < BFL / f < 1.5.

[0008] More preferably, the effective focal length f of the optical lens, the maximum field of view angle FOV of the optical lens, and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 60° < (f × FOV) / IH < 80°; the combined focal length f123 of the first lens, the second lens, and the third lens and the combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens satisfy: -49 < f123 / f456 < -6.1.

[0009] More preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 3.3 < f3 / f < 5.5; the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 7.9 < (R5 + R6) / (R5 - R6) < 11.3.

[0010] More preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.8 < f6 / f < 3.2; the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: 0.2 < (R11 - R12) / (R11 + R12) < 0.9.

[0011] More preferably, the effective focal length f of the optical lens and the radius of curvature R5 of the object side surface of the third lens satisfy: -1.8 < R5 / f < -1.1; the effective focal length f of the optical lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -1.4 < R6 / f < -0.8.

[0012] More preferably, the effective focal length f of the optical lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: -5.4 < R10 / f < -3.4; the effective focal length f of the optical lens and the radius of curvature R11 of the object side surface of the sixth lens satisfy: -5.4 < R11 / f < -2.4.

[0013] More preferably, the radius of curvature R5 of the object side surface of the third lens and the focal length f3 of the third lens satisfy: -0.4 < R5 / f3 < -0.2; the radius of curvature R11 of the object side surface of the sixth lens and the focal length f6 of the sixth lens satisfy: -2.5 < R11 / f6 < -0.9.

[0014] Further preferably, the sagittal height Sag5 of the clear aperture on the object side of the third lens and the clear aperture diameter d5 of the object side of the third lens satisfy: -0.5 < Sag5 / d5 < -0.2; the sagittal height Sag11 of the clear aperture on the object side of the sixth lens and the clear aperture diameter d11 of the object side of the sixth lens satisfy: -0.3 < Sag11 / d11 < 0.

[0015] Compared with the prior art, the optical lens provided by the present invention, through specific surface shape settings and reasonable optical power distribution, not only effectively shortens the overall length of the optical lens but also has a large aperture, enabling the lens to achieve high-definition imaging even in a dim environment. At the same time, the lens also has a large field of view angle, capable of obtaining more scene information and meeting the requirements of large-range shooting. Additionally, it can reasonably correct the overall aberration of the optical lens, has high illuminance, can achieve high-definition imaging, and improve the imaging quality of the optical lens. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] Figure 2 is an astigmatism curve diagram of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 3 is an axial aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0019] Figure 4 is a lateral chromatic aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0020] Figure 5 is a relative illumination curve diagram of the optical lens in Embodiment 1 of the present invention.

[0021] Figure 6 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0022] Figure 7 is an astigmatism curve diagram of the optical lens in Embodiment 2 of the present invention.

[0023] Figure 8 is an axial aberration curve diagram of the optical lens in Embodiment 2 of the present invention.

[0024] Fig. 9 is a lateral chromatic aberration curve diagram of the optical lens in Embodiment 2 of the present invention.

[0025] Fig.10 is a relative illumination curve diagram of the optical lens in Embodiment 2 of the present invention.

[0026] Fig.11 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0027] Fig.12 4 is an astigmatism curve diagram of the optical lens in Example 3 of the present invention.

[0028] Fig.13 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0029] Fig.14 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0030] Fig.15 This is a relative illumination curve diagram of the optical lens in Example 3 of the present invention.

[0031] Fig.16 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

[0032] Fig.17 4 is an astigmatism curve diagram of the optical lens in Example 4 of the present invention.

[0033] Fig.18 4 is an axial aberration curve diagram of the optical lens in Example 4 of the present invention.

[0034] Fig.19 Graph showing the vertical axis chromatic aberration of the optical lens in Example 4 of the present invention.

[0035] Fig. 20 This is a relative illumination curve diagram of the optical lens in Example 4 of the present invention.

[0036] Fig.21 Schematic diagram of the structure of the optical lens in Example 5 of the present invention.

[0037] Fig. 22 4 is an astigmatism curve diagram of the optical lens in Example 5 of the present invention.

[0038] Fig.23 Graph showing the axial aberration of the optical lens in Embodiment 5 of the present invention.

[0039] Fig.24 Graph showing the vertical axis chromatic aberration of the optical lens in Example 5 of the present invention.

[0040] Fig.25 This is a relative illumination curve diagram of the optical lens in Example 5 of the present invention.

[0041] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] The optical lens provided by the embodiment of the present invention is composed of six lenses, which include: a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens in sequence from the object side to the imaging surface along the optical axis.

[0050] In some embodiments, the first lens may have a negative optical power, with a convex object side surface and a concave image side surface. The second lens may have a negative optical power, with a concave object side surface and a convex image side surface. The third lens may have a positive optical power, with a concave object side surface and a convex image side surface. The fourth lens may have a positive optical power, with a convex object side surface and a convex image side surface. The fifth lens may have a negative optical power, with a concave object side surface and a convex image side surface. The sixth lens may have a positive optical power, with a concave object side surface and a convex image side surface.

[0051] In some embodiments, the optical lens may further include an aperture, and the aperture may be located between the third lens and the fourth lens. It is understood that the aperture is used to limit the amount of light entering to change the brightness of the image. When the aperture is located between the third lens and the fourth lens, it is convenient to correct the aperture aberration.

[0052] In some embodiments, the optical lens may further include a filter, which may be disposed between the sixth lens and the imaging surface. The filter is used to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0053] In some embodiments, the fourth lens and the fifth lens can be glued to form a glued 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 difficulty of the processing technology of the optical lens and improving the assembly yield of the optical lens.

[0054] In some embodiments, the object side curvature radius R5 of the third lens and the object side curvature radius R11 of the sixth lens satisfy: -0.7<(R5-R11) / (R5+R11)<-0.2. Meeting the above range can reduce the light deflection angle and make the light trend more stable; at the same time, it can correct coma and field curvature, improve the flatness of the image, and enhance the imaging quality of the optical lens. More specifically, -0.57<(R5-R11) / (R5+R11)<-0.31.

[0055] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 63° < FOV / Fno < 88°. Meeting the above range defines that the optical lens has an appropriate field of view and aperture value, can collect light at large angles, and obtain good imaging quality. More specifically, 69.13° < FOV / Fno < 79.76°.

[0056] In some embodiments, the true image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.3 < IH / EPD < 3.3. Meeting the above range can increase the width of the light beam incident on the optical lens, improve the brightness of the optical lens at the image plane, and avoid vignetting. More specifically, 2.55 < IH / EPD < 3.08.

[0057] In some embodiments, the true image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 1.4 < IH / f < 2.1. Meeting the above range can achieve the large image plane characteristic of the lens, can match a larger size of the chip, and realize high-pixel imaging of the lens. More specifically, 1.57 < IH / f < 1.89.

[0058] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.9 < BFL / f < 1.5. Meeting the above range is beneficial to balance between obtaining good imaging quality and having an optical back focal length that is easy to assemble, ensuring the imaging quality of the optical lens while reducing the assembly process difficulty of the camera module. More specifically, 1 < BFL / f < 1.4.

[0059] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 60° < (f × FOV) / IH < 80°. Meeting the above range, by reasonably restricting the relationship between the focal length, field of view, and image height of the optical lens, it can ensure that the optical lens has large field of view and large image plane characteristics, so that the optical lens has good optical performance and can well capture the details of the object to be photographed. More specifically, 62.3° < (f × FOV) / IH < 72.28°.

[0060] In some embodiments, the combined focal length f123 of the first lens, the second lens, and the third lens and the combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens satisfy: -49 < f123 / f456 < -6.1. Meeting the above range, by reasonably setting the relationship between the lens groups before and after the aperture, it is beneficial to balance various aberrations of the system and improve the overall imaging quality. More specifically, -44.61 < f123 / f456 < -6.77.

[0061] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 3.3 < f3 / f < 5.5; the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 7.9 < (R5 + R6) / (R5 - R6) < 11.3. Meeting the above ranges defines that the third lens has an appropriate positive optical power and surface shape, has the effect of converging light rays, and when paired with the negative optical power of the second lens, can converge the light rays passing through the second lens, reduce the height of peripheral light rays, and is beneficial to reducing the aperture of the rear lens. More specifically, 3.63 < f3 / f < 5.02; 8.77 < (R5 + R6) / (R5 - R6) < 10.32.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.8 < f6 / f < 3.2; the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: 0.2 < (R11 - R12) / (R11 + R12) < 0.9. Meeting the above ranges defines that the sixth lens has a suitable positive optical power and surface shape, which is beneficial to light convergence, enables the light rays to smoothly transition to the rear, reduces the height of the light rays incident on the rear, slows down the upward trend of the light rays, avoids light energy loss caused by too large a chief ray angle between the large field of view light rays and the chip when reaching the imaging surface, is beneficial to improving the illuminance of the edge field of view, and is beneficial to achieving a short overall optical length. More specifically, 1.97 < f6 / f < 2.9; 0.46 < (R11 - R12) / (R11 + R12) < 0.68.

[0063] In some embodiments, the effective focal length f of the optical lens and the radius of curvature R5 of the object side surface of the third lens satisfy: -1.8 < R5 / f < -1.1; the effective focal length f of the optical lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -1.4 < R6 / f < -0.8. Meeting the above ranges, by reasonably setting the shape of the third lens, it is beneficial to the smooth transition of light rays, better corrects the aberrations and distortions brought by the front lens, and improves the overall imaging quality. More specifically, -1.63 < R5 / f < -1.14; -1.3 < R6 / f < -0.91.

[0064] In some embodiments, the effective focal length f of the optical lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: -5.4 < R10 / f < -3.4; the effective focal length f of the optical lens and the radius of curvature R11 of the object side surface of the sixth lens satisfy: -5.4 < R11 / f < -2.4. Meeting the above ranges is beneficial to balancing the astigmatism and field curvature of the optical lens and improving the imaging quality of the optical lens. More specifically, -4.9 < R10 / f < -3.74; -4.95 < R11 / f < -2.72.

[0065] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the focal length f3 of the third lens satisfy: -0.4 < R5 / f3 < -0.2; the radius of curvature R11 of the object side surface of the sixth lens and the focal length f6 of the sixth lens satisfy: -2.5 < R11 / f6 < -0.9. Satisfying the above ranges is beneficial to slowing down the deflection degree of the incident light, avoiding excessive aberration caused by too strong refraction changes, and at the same time is beneficial to balancing various aberrations generated by the lens group and improving the overall imaging quality. More specifically, -0.34 < R5 / f3 < -0.29; -2.28 < R11 / f6 < -1.02.

[0066] In some embodiments, the sagittal height Sag5 of the clear aperture of the object side surface of the third lens and the clear aperture diameter d5 of the object side surface of the third lens satisfy: -0.5 < Sag5 / d5 < -0.2; the sagittal height Sag11 of the clear aperture of the object side surface of the sixth lens and the clear aperture diameter d11 of the object side surface of the sixth lens satisfy: -0.3 < Sag11 / d11 < 0. Satisfying the above ranges helps to control the trend of the light rays in the marginal field of view and highlight the detailed information of the central field of view of the optical lens. More specifically, -0.38 < Sag5 / d5 < -0.29; -0.19 < Sag11 / d11 < -0.08.

[0067] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 4.4 < TTL / f < 7.2. Satisfying the above range can effectively limit the length of the lens and is beneficial to the miniaturization of the optical lens. More specifically, 4.85 < TTL / f < 6.69.

[0068] 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: 2.7 < TTL / IH < 4.2. Satisfying the above range, by reasonably restricting the ratio of the overall length of the optical lens to the image height, it is ensured that the lens has a larger image plane under the same overall length, achieving the balance of miniaturization and large image plane of the optical lens and improving the market competitiveness. More specifically, 3.07 < TTL / IH < 3.83.

[0069] In some embodiments, the overall optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis respectively satisfy: 0.4 < ∑CT / TTL < 0.65. Satisfying the above range can effectively compress the overall length of the optical lens and is beneficial to the structural design and production process of the optical lens. More specifically, 0.5 < ∑CT / TTL < 0.58.

[0070] In some embodiments, the effective focal length f of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis satisfy: 2.2 < ∑CT / f < 4.1. Meeting the above range, by reasonably distributing the central thicknesses of each lens, the manufacturing yield of the optical lens can be improved, and at the same time, it helps to shorten the total length of the optical lens and maintain its miniaturization. More specifically, 2.45 < ∑CT / f < 3.74.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -60 < f1 / f < -4.9. Meeting the above range makes the first lens have an appropriate negative optical power, which can diverge the light passing through it, facilitating the realization of a small front aperture. More specifically, -55.28 < f1 / f < -5.41.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -4 < f2 / f < -2.1. Meeting the above range makes the second lens have a negative optical power and the function of diverging light. At the same field of view angle, it further diverges the light emerging from the image side of the first lens, enabling the central light rays and marginal light rays of each field of view to be dispersed, allowing the rear optical system to have a larger light receiving surface to receive the light emerging from the image side of the second lens, achieving a larger light input, and facilitating an increase in relative illumination. More specifically, -3.65 < f2 / f < -2.37.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.8 < f4 / f < 1.3. Meeting the above range can effectively converge the light, enabling the fourth lens with a positive optical power and the fifth lens with a negative optical power to cooperate, adjusting the optical path difference between different fields of view, improving the resolution, facilitating the smooth entry of light into the rear lens, further reducing astigmatism, and correcting the off-axis point aberration of the optical lens. More specifically, 0.86 < f4 / f < 1.17.

[0074] 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 < -1. Meeting the above range can diverge the light emerging from the fourth lens, making the light rays in the marginal field of view show an upward trend, facilitating the image points on the imaging surface to be away from the optical axis, which is conducive to achieving the effect of matching with a large chip, obtaining a larger picture, and being able to be glued to the fourth lens with a positive optical power, effectively eliminating aberrations and improving the resolution ability of the optical lens. More specifically, -1.58 < f5 / f < -1.07.

[0075] In some embodiments, the combined focal length f45 of the fourth lens and the fifth lens and the combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens satisfy: 1.45 < f45 / f456 < 2.8. Meeting the above range, the fourth and fifth lenses form a cemented lens with positive optical power, which can further converge the incident light, reduce the loss of light energy, and at the same time enable the diverging light to converge smoothly and enter the rear, further making the light trend transition smoothly and improving the relative illumination of the edge field of view. More specifically, 1.59 < f45 / f456 < 2.58.

[0076] In some embodiments, the focal length f3 of the third lens and the focal length f6 of the sixth lens satisfy: 1.5 < f3 / f6 < 2.3; the object-side curvature radius R5 of the third lens and the object-side curvature radius R11 of the sixth lens satisfy: 0.2 < R5 / R11 < 0.6. Meeting the above range is beneficial to slowing down the deflection degree of the incident light, avoiding excessive aberration caused by overly strong refraction changes, and at the same time is beneficial to balancing various aberrations generated by the lens group and improving the overall imaging quality. More specifically, 1.67 < f3 / f6 < 2.11; 0.27 < R5 / R11 < 0.52.

[0077] In some embodiments, the object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: -0.9 < R9 / f < -0.5; the image-side curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.2 < R12 / f < -0.7. Meeting the above range, the object side of the fifth lens and the image side of the sixth lens adopt a lens shape close to a concentric circle, which can effectively reduce the optical path difference between the center and the periphery of the lens and is beneficial to correcting the distortion of the optical lens. More specifically, -0.82 < R9 / f < -0.6; -1.09 < R12 / f < -0.78.

[0078] In some embodiments, the image-side curvature radius R4 of the second lens and the object-side curvature radius R5 of the third lens satisfy: 0.5 < (R4 - R5) / (R4 + R5) < 1. Meeting the above range can effectively slow down the deflection degree of the light from the second lens entering the third lens, is beneficial to maintaining the miniaturization of the lens head, and at the same time increases the light flux entering the lens. More specifically, 0.87 < (R4 - R5) / (R4 + R5) < 0.98.

[0079] In some embodiments, the object-side curvature radius R9 of the fifth lens and the image-side curvature radius R10 of the fifth lens satisfy: -0.9 < (R9 - R10) / (R9 + R10) < -0.4. Meeting the above range is beneficial to the smooth transition of light, better correcting the aberration and distortion brought by the previous lens, and improving the overall imaging quality. More specifically, -0.78 < (R9 - R10) / (R9 + R10) < -0.64.

[0080] In some embodiments, 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 seventh lens satisfy: -0.2 < (R10 - R11) / (R10 + R11) < 0.5. Satisfying the above range can reduce the light deflection angle and make the light path more stable; at the same time, it can correct coma and field curvature, improve the flatness of imaging, and enhance the imaging quality of the optical lens. More specifically, -0.02 < (R10 - R11) / (R10 + R11) < 0.27.

[0081] In some embodiments, the optical lens satisfies the conditional formula: 2.9mm < f < 4.8mm, 1.8mm < EPD < 3mm, 18mm < TTL < 24.7mm, 1.4 < Fno < 1.8, 10.8° < CRA < 25.7°, 4mm < BFL < 5.1mm, 100° < FOV < 140°, 4.7mm < IH < 7.6mm; where f represents the effective focal length 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, CRA represents the principal ray incident angle at the maximum image height of the optical lens, BFL represents the back focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, and IH represents the true image height corresponding to the maximum field of view angle of the optical lens. Satisfying the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least the characteristics of a large aperture, a large image plane, and a large field of view angle. More specifically, 3.16mm < f < 4.38mm, 1.97mm < EPD < 2.7mm, 20.13mm < TTL < 22.53mm, 1.57 < Fno < 1.66, 11.96° < CRA < 23.39°, 4.4mm < BFL < 4.69mm, 111° < FOV < 127°, 5.26mm < IH < 6.91mm.

[0082] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The first lens in the optical lens provided by the present invention uses a glass lens, and the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens use plastic lenses. The optical lens of the present invention adopts a glass-plastic hybrid structure to improve the thermal stability.

[0083] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens may be spherical lenses or aspherical lenses. Compared with spherical structures, aspherical structures can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of lenses, and better miniaturizing the lens. More specifically, the first lens of the present invention adopts a spherical lens, and the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens can all adopt aspherical lenses, which can effectively reduce the aberration of the optical lens, thereby reducing the number of lenses and the size of lenses, and better miniaturizing the lens.

[0084] In various embodiments of the present invention, when the lens is an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations: ; Among them, z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the surface vertex, K is the quadratic surface coefficient, B, C, D, E, F, G, and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients respectively.

[0085] 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.

[0086] Example 1 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, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a filter G1.

[0087] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave; The second lens L2 has negative refractive power, its object-side surface S3 is concave, and its image-side surface S4 is convex; The third lens L3 has positive refractive power, its object-side surface S5 is concave, and its image-side surface S6 is convex; The fourth lens L4 has positive refractive power, its object-side surface S7 is convex, and its image-side surface S8 is convex; The fifth lens L5 has negative refractive power, its object-side surface S8 is concave, and its image-side surface S9 is convex; The fourth lens L4 and the fifth lens L5 form a cemented lens group with positive refractive power, that is, the cemented surface between the image side surface of the fourth lens L4 and the object side surface of the fifth lens L5 is S8; The sixth lens L6 has positive refractive power, an object-side surface S10 thereof is concave, and an image-side surface S11 thereof is convex; The object side surface S12 and the image side surface S13 of the filter G1 are both planes; The imaging surface S14 is a plane.

[0088] The first lens L1 is a glass spherical lens, and the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are all plastic aspherical lenses.

[0089] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0090] Table 1-1 The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0091] Table 1-2 In this embodiment, the astigmatism curve, the axial aberration curve, the vertical chromatic aberration curve, and the relative illumination curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 shown.

[0092] Figure 2 The astigmatism curve of the optical lens 100 in this embodiment is shown, which represents the astigmatism of light in the meridional image plane and the sagittal image plane, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.1mm, indicating that the optical lens 100 can correct the astigmatism well.

[0093] Figure 3 The axial aberration curve of the optical lens 100 in this embodiment is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface, 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 ±0.02mm, indicating that the optical lens 100 can better correct the axial aberration.

[0094] Figure 4The vertical axis chromatic aberration curve of the optical lens 100 in this embodiment 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 axis 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 axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±5 μm, indicating that the optical lens 100 can correct chromatic aberration very well.

[0095] Figure 5 The relative illumination curve of the optical lens 100 in this embodiment is shown, which represents the relative illumination values ​​at different viewing angles on the imaging plane, with the horizontal axis representing the half viewing angle (unit: °) and the vertical axis representing the relative illumination. It can be seen from the figure that the relative illumination value of the optical lens 100 is still greater than 50% at the edge of the viewing field, indicating that the optical lens 100 has an excellent relative illumination.

[0096] Example 2 See also Figure 6 , 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.

[0097] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0098] Table 2-1 The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0099] Table 2-2 In this embodiment, the astigmatism curve, the axial aberration curve, the vertical axis chromatic aberration curve, and the relative illumination curve of the optical lens 200 are respectively as follows: Figure 7 , Figure 8 , Fig. 9 , Fig.10 shown.

[0100] from Figure 7 It can be seen that the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 200 can correct the astigmatism well.

[0101] from Figure 8 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.

[0102] from Fig. 9It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±5μm, indicating that the optical lens 200 can correct chromatic aberration very well.

[0103] from Fig.10 It can be seen that the relative illumination value of the optical lens 200 is still greater than 60% at the edge of the field of view, indicating that the optical lens 200 has excellent relative illumination.

[0104] Example 3 See also Fig.11 , 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.

[0105] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0106] Table 3-1 The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0107] Table 3-2 In this embodiment, the astigmatism curve, the axial aberration curve, the vertical axis chromatic aberration curve, and the relative illumination curve of the optical lens 300 are respectively as follows: Fig.12 , Fig.13 , Fig.14 , Fig.15 shown.

[0108] from Fig.12 It can be seen that the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 300 can correct the astigmatism well.

[0109] from Fig.13 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.

[0110] from Fig.14 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±4μm, indicating that the optical lens 300 can correct chromatic aberration very well.

[0111] from Fig.15 It can be seen that the relative illumination value of the optical lens 300 is still greater than 70% at the edge of the field of view, indicating that the optical lens 300 has excellent relative illumination.

[0112] Example 4 See also Fig.16 , 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.

[0113] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0114] Table 4-1 The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0115] Table 4-2 In this embodiment, the astigmatism curve, the axial aberration curve, the vertical chromatic aberration curve, and the relative illumination curve of the optical lens 400 are respectively as follows: Fig.17 , Fig.18 , Fig.19 , Fig. 20 shown.

[0116] from Fig.17 It can be seen that the astigmatism of the meridian image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 400 can correct the astigmatism well.

[0117] from Fig.18 It can be seen that the offset of the axial aberration is controlled within ±0.03 mm, indicating that the optical lens 400 can correct the axial aberration well.

[0118] from Fig.19 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±5μm, indicating that the optical lens 400 can correct chromatic aberration very well.

[0119] from Fig. 20 It can be seen that the relative illumination value of the optical lens 400 is still greater than 65% at the edge of the field of view, indicating that the optical lens 400 has excellent relative illumination.

[0120] Example 5 See also Fig.21 , shown is a schematic diagram of the structure of an optical lens 500 provided in Example 5 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.

[0121] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0122] Table 5-1 The surface parameters of the aspheric lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0123] Table 5-2 In this embodiment, the astigmatism curve, the axial aberration curve, the vertical axis chromatic aberration curve, and the relative illumination curve of the optical lens 500 are respectively as follows: Fig. 22 , Fig.23 , Fig.24 , Fig.25 shown.

[0124] from Fig. 22 It can be seen that the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 500 can correct the astigmatism well.

[0125] from Fig.23 It can be seen that the offset of the axial aberration is controlled within ±0.02 mm, indicating that the optical lens 500 can correct the axial aberration well.

[0126] from Fig.24 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±5μm, indicating that the optical lens 500 can correct chromatic aberration very well.

[0127] from Fig.25 It can be seen that the relative illumination value of the optical lens 500 is still greater than 65% at the edge of the field of view, indicating that the optical lens 500 has excellent relative illumination.

[0128] Please refer to Table 6-1 and Table 6-2, which are the optical characteristics corresponding to the above-mentioned embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the real image height IH corresponding to the maximum field of view angle, the main ray incident angle CRA at the maximum image height, the maximum field of view angle FOV and the numerical value corresponding to each conditional expression in each embodiment.

[0129] Table 6-1 Table 6-2 In summary, the optical lens provided by the present invention has at least the following advantages: (1) Through the specific surface shape setting and reasonable optical focal length distribution, the lens has a large aperture, which can achieve high-definition imaging even in dim environments; at the same time, it has a large field of view, so that more scene information can be obtained to meet the needs of large-scale shooting. The lens has a small head size, which is conducive to miniaturization and conforms to the current development of increasingly lightweight and high-performance security lenses.

[0130] (2) The optical lens of the present invention can reasonably correct the overall aberration of the optical lens, reduce the aberration, improve the resolution of the optical lens, achieve high-definition imaging, have high illumination, and improve the imaging quality of the optical lens.

[0131] (3) The glass-plastic hybrid structure improves the stability of the lens under high and low temperature conditions while also improving the imaging quality. At the same time, the lens has a larger image surface, which can be well matched to the chip, ensuring good resolution quality.

[0132] 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.

[0133] 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, consisting of six lenses, characterized in that: It successively includes from the object side to the imaging surface along the optical axis: A first lens with a negative optical power, whose object side is convex and whose image side is concave; A second lens with a negative optical power, whose object side is concave and whose image side is convex; A third lens with a positive optical power, whose object side is concave and whose image side is convex; A fourth lens with a positive optical power, whose object side is convex and whose image side is convex; A fifth lens with a negative optical power, whose object side is concave and whose image side is convex; A sixth lens with a positive optical power, whose object side is concave and whose image side is convex; Wherein, the curvature radius R5 of the object side of the third lens and the curvature radius R11 of the object side of the sixth lens satisfy: -0.7 < (R5 - R11) / (R5 + R11) < -0.

2.

2. The optical lens according to claim 1, characterized in that: The maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 63° < FOV / Fno < 88°; The true image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.3 < IH / EPD < 3.

3.

3. The optical lens according to claim 1, characterized in that: The true image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 1.4 < IH / f < 2.1; The back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.9 < BFL / f < 1.

5.

4. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens, the maximum field of view FOV of the optical lens and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 60° < (f × FOV) / IH < 80°; The combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f456 of the fourth lens, the fifth lens and the sixth lens satisfy: -49 < f123 / f456 < -6.

1.

5. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 3.3 < f3 / f < 5.5; The curvature radius R5 of the object side of the third lens and the curvature radius R6 of the image side of the third lens satisfy: 7.9 < (R5 + R6) / (R5 - R6) < 11.

3.

6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.8 < f6 / f < 3.2; The curvature radius R11 of the object side of the sixth lens and the curvature radius R12 of the image side of the sixth lens satisfy: 0.2 < (R11 - R12) / (R11 + R12) < 0.

9.

7. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the curvature radius R5 of the object side of the third lens satisfy: -1.8 < R5 / f < -1.1; The effective focal length f of the optical lens and the curvature radius R6 of the image side of the third lens satisfy: -1.4 < R6 / f < -0.

8.

8. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the image-side curvature radius R10 of the fifth lens satisfy: -5.4 < R10 / f < -3.4; the effective focal length f of the optical lens and the object-side curvature radius R11 of the sixth lens satisfy: -5.4 < R11 / f < -2.

4.

9. The optical lens according to claim 1, characterized in that: The object-side curvature radius R5 of the third lens and the focal length f3 of the third lens satisfy: -0.4 < R5 / f3 < -0.2; the object-side curvature radius R11 of the sixth lens and the focal length f6 of the sixth lens satisfy: -2.5 < R11 / f6 < -0.

9.

10. The optical lens according to claim 1, characterized in that: The object-side clear aperture sagittal height Sag5 of the third lens and the object-side clear aperture d5 of the third lens satisfy: -0.5 < Sag5 / d5 < -0.2; the object-side clear aperture sagittal height Sag11 of the sixth lens and the object-side clear aperture d11 of the sixth lens satisfy: -0.3 < Sag11 / d11 < 0.

Images