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 negative focal power and a fourth lens with negative focal power from the object side to the imaging surface, the image side surface of the second lens is a convex surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the fourth lens has positive focal power, the object side surface of the fourth lens is a convex surface near the optical axis, and the image side surface of the fourth lens is a convex surface; the fifth lens has negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a concave surface near the optical axis; 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; and the object side surface of the seventh lens is a convex surface near the optical axis, and the image side surface of the seventh lens is a concave surface near the optical axis. According to the optical lens provided by the invention, through specific surface shape matching and reasonable focal power distribution, the imaging quality of the optical lens can be improved, and the optical lens has the advantage of excellent imaging quality.

Description

Technical Field

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

[0002] With the rapid development of fields such as drones, security, and automobiles, the pursuit of the imaging effect of the lenses carried by them has become more diversified. At present, drones are developing rapidly, winning the love of consumers with their unique high-altitude perspective and wide shooting range. Correspondingly, the demand for the optical lenses supporting them is also increasing. The optical lenses carried by them require both high-definition image quality and the ability to present large local details, so as to achieve that the local details can be vividly displayed even in the high-altitude view and capture local close-up pictures.

[0003] Therefore, it is necessary to develop an optical lens with good imaging effect to better meet the market demand. Summary of the Invention

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

[0005] The present invention provides an optical lens, which has a total of seven lenses and successively includes, along the optical axis from the object side to the imaging surface:

[0006] A first lens with negative optical power, whose object side is convex and whose image side is concave;

[0007] A second lens with positive optical power, whose image side is convex;

[0008] A third lens with positive optical power, whose object side is convex and whose image side is convex;

[0009] A fourth lens with positive optical power, whose object side is convex near the optical axis and whose image side is convex;

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

[0011] A sixth lens with positive optical power, whose object side is concave and whose image side is convex;

[0012] A seventh lens with negative optical power, whose object side is convex near the optical axis and whose image side is concave near the optical axis;

[0013] Wherein, the maximum field of view FOV of the optical lens satisfies: 115° < FOV < 150°; the true image height IH corresponding to the maximum field of view of the optical lens, the maximum field of view FOV of the optical lens and the effective focal length f of the optical lens satisfy: 43° < (f × FOV) / IH < 50°.

[0014] More preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.8 < f1 / f < -1.2; the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R2 of the image side surface of the first lens satisfy: 2.5 < R1 / R2 < 5.

[0015] More preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.8 < f2 / f < 2.8; the effective focal length f of the optical lens and the radius of curvature R4 of the image side surface of the second lens satisfy: -2 < R4 / f < -0.5.

[0016] More preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.3 < f3 / f < 2; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.7 < f4 / f < 2.7.

[0017] More preferably, the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: 0.4 < f3 / f4 < 1.

[0018] More preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.5 < f5 / f < -1; the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -2.5 < f5 / f6 < -1.

[0019] More preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.5 < f6 / f < 0.85.

[0020] More preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -1.2 < f7 / f < -0.7.

[0021] More preferably, the overall optical length TTL of the optical lens and the back focal length BFL of the optical lens satisfy: 0.18 < BFL / TTL < 0.25; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.45 < BFL / f < 0.6.

[0022] More preferably, the focal length f1 of the first lens and the focal length f7 of the seventh lens satisfy: 1.1 < f1 / f7 < 2; the clear aperture DM11 of the object side surface of the first lens and the clear aperture DM72 of the image side surface of the seventh lens satisfy: 0.5 < DM11 / DM72 < 0.65.

[0023] Further preferably, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 2.2 < IH / f < 3.2; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.83 < TTL / IH < 0.93.

[0024] Compared with the prior art, the optical lens provided by the present invention uses seven lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, enabling the lens to have one or more advantages such as a large wide angle, miniaturization, and high imaging quality. 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, in which:

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

[0027] Figure 2 is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

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

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

[0030] Figure 5 is a lateral chromatic aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 6 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 7 is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 8 is an MTF curve diagram of the optical lens in Embodiment 2 of the present invention.

[0034] Fig. 9 is an axial aberration curve diagram of the optical lens in Embodiment 2 of the present invention.

[0035] Fig.10 is a lateral chromatic aberration curve diagram of the optical lens in Embodiment 2 of the present invention.

[0036] Fig.11Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0037] Fig.12 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0038] Fig.13 This is the MTF curve diagram of the optical lens in Example 3 of the present invention.

[0039] Fig.14 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0040] Fig.15 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 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 comprises seven lenses in total, and the optical lens comprises, in order from the object side to the imaging surface along the optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens.

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

[0051] In some embodiments, the optical lens may further include an aperture, and the aperture may be located between the second lens and the third 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 second lens and the third lens, it is convenient to correct the aperture aberration.

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

[0053] In some embodiments, the maximum field of view FOV of the optical lens satisfies: 115° < FOV < 150°. Meeting the above conditions is beneficial to achieving the ultra-wide-angle characteristic, so as to be able to obtain more scene information and meet the requirements of large-range detection of the optical lens.

[0054] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens, the maximum field of view angle FOV of the optical lens, and the effective focal length f of the optical lens satisfy: 43° < (f × FOV) / IH < 50°. Meeting the above conditions, by reasonably restricting the relationship between the focal length, field of view angle, and image height of the optical lens, it is beneficial to achieve the balance between the large field of view angle and large target surface imaging of the optical lens.

[0055] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.8 < f1 / f < -1.2. Meeting the above conditions can make the first lens have a large negative refractive power, avoid the over-concentration of negative optical power, and at the same time is beneficial to increasing the field of view angle, and is beneficial to collecting as much marginal field light as possible into the rear optical lens to achieve large-angle light collection.

[0056] In some embodiments, the curvature radius R1 of the object side surface of the first lens and the curvature radius R2 of the image side surface of the first lens satisfy: 2.5 < R1 / R2 < 5. Meeting the above conditions can effectively control the meniscus surface shape of the first lens, and is beneficial to increasing the field of view angle while controlling the front aperture of the optical lens to achieve the balance between large field of view and miniaturization.

[0057] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.8 < f2 / f < 2.8. Meeting the above conditions can effectively converge the large-range light entering the system, and 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 aberration.

[0058] In some embodiments, the effective focal length f of the optical lens and the curvature radius R4 of the image side surface of the second lens satisfy: -2 < R4 / f < -0.5. Meeting the above conditions can effectively converge the large-range light entering the system, and at the same time is beneficial to the rear optical system to correct large-angle aberration, so as to achieve the balance between the miniaturization and high pixel of the optical lens.

[0059] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.3 < f3 / f < 2. Meeting the above conditions, by reasonably setting the focal length of the third lens, it is beneficial to the smooth transition of light, facilitating the correction of astigmatism and field curvature, and improving the imaging quality of the optical lens.

[0060] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.7 < f4 / f < 2.7. Meeting the above conditions is beneficial to improving the light converging ability of the optical lens, and at the same time can balance the aberration of the optical lens, improving the imaging quality of the optical lens.

[0061] In some embodiments, the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: 0.4 < f3 / f4 < 1. Meeting the above conditions is conducive to the smooth entry of divergent light into the rear optical system, reducing the difficulty of correcting field curvature and distortion, and improving the overall resolution.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.5 < f5 / f < -1. Meeting the above conditions can make the fifth lens have a large negative optical power, which is beneficial to diverging the light converged by the third lens and the fourth lens, and increasing the image height of the optical lens.

[0063] In some embodiments, the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -2.5 < f5 / f6 < -1. Meeting the above conditions is beneficial to the smooth transition of light, and at the same time corrects various aberrations of the optical lens, improving the imaging quality of the optical lens.

[0064] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.5 < f6 / f < 0.85; the radius of curvature R11 of the object side of the sixth lens and the radius of curvature R12 of the image side of the sixth lens satisfy: 1.1 < (R11 + R12) / (R11 - R12) < 1.35. Meeting the above conditions can control the contribution of spherical aberration of the sixth lens within a reasonable range, enabling the lens to have a high axial imaging resolution ability, which is beneficial to achieving high-definition imaging of the lens.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -1.2 < f7 / f < -0.7. Meeting the above conditions is beneficial to increasing the degree of divergence of light, increasing the area of light entering the imaging surface, realizing large target surface imaging of the lens, and improving the imaging quality of the optical lens.

[0066] In some embodiments, the total optical length TTL of the optical lens and the back focal length BFL of the optical lens satisfy: 0.18 < BFL / TTL < 0.25; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.45 < BFL / f < 0.6. Meeting the above conditions can make the lens have an appropriate back focus, ensure the compatibility between the lens and the camera body, and make the structure of the lens more compact.

[0067] In some embodiments, the focal length f1 of the first lens and the focal length f7 of the seventh lens satisfy: 1.1 < f1 / f7 < 2. Meeting the above conditions, by reasonably setting the focal length relationship between the first and the last lenses in the lens, while ensuring that as much light as possible enters the system, the area of light entering the imaging surface is increased, which is beneficial to achieving large image plane imaging of the lens.

[0068] In some embodiments, the clear aperture DM11 on the object side of the first lens and the clear aperture DM72 on the image side of the seventh lens satisfy: 0.5 < DM11 / DM72 < 0.65. Meeting the above conditions, while ensuring that light within a large range enters the system, the aperture size of the lens is effectively reduced, which is beneficial to achieving the balance between large field of view and small aperture of the lens.

[0069] In some embodiments, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 2.2 < IH / f < 3.2. Meeting the above conditions can not only achieve the wide-angle characteristic to meet the large-range shooting requirements, but also achieve the large image plane characteristic to improve the imaging quality of the optical lens.

[0070] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.83 < TTL / IH < 0.93. Meeting the above conditions can better achieve the miniaturization of the lens. At the same time, when ensuring the same total length of the lens, it has a larger image plane and can match a larger-size imaging chip to achieve high-definition imaging.

[0071] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f satisfy: 2 < TTL / f < 3. Meeting the above conditions can effectively limit the length of the lens, which is beneficial to achieving the miniaturization of the optical lens.

[0072] In some embodiments, 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: -0.5 < R5 / R6 < -0.005; the curvature radius R7 of the object side of the fourth lens and the curvature radius R8 of the image side of the fourth lens satisfy: -10 < R7 / R8 < -1. Meeting the above conditions is beneficial to better achieving the convergence of light, shortening the distance for light to reach the next lens, and thus reducing the total length of the optical lens.

[0073] 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 < R9 / R10 < -1.2. By satisfying the above conditions, the light converged by the front lens can be diverged so that it can reach a higher imaging position, appropriately separate the optical paths of the light rays in each field of view, and gently diverge them to the rear lens system.

[0074] In some embodiments, 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: 1.5 < (R13 + R14) / (R13 - R14) < 2. By satisfying the above conditions, the angle of incidence of the marginal field of view on the imaging surface can be appropriately suppressed, and more light beams can be effectively transmitted to the imaging surface, improving the relative illumination of the optical lens.

[0075] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 6 < IH / EPD < 8. By satisfying the above conditions, the width of the light beam incident on the optical lens can be increased, so that the brightness of the optical lens at the image plane is improved and vignetting is avoided.

[0076] In some embodiments, the optical lens satisfies the conditional formula: 2mm < f < 3mm, 5mm < TTL < 7mm, 6mm < IH < 7.5mm, 36° < CRA < 40°, where f represents the effective focal length of the optical lens, TTL represents the total optical length of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, and CRA represents the principal ray angle of incidence of the optical lens. By satisfying the above conditions, it shows that the optical lens provided by the embodiments of the present invention at least has the characteristics of a large image plane and miniaturization, and can match an imaging chip with a larger CRA to achieve high-definition imaging.

[0077] In some embodiments, the seven lenses in the optical lens can all be made of plastic lenses or adopt a glass-plastic hybrid material matching structure. Preferably, the optical lens of the present invention adopts a seven-piece glass-plastic hybrid matching lens structure, which can enable the optical lens to better match a large target surface chip to achieve high-definition imaging, and at the same time can achieve a reasonable balance of miniaturization, large image plane and large wide angle of the optical lens. Specifically, the second lens can be made of a glass lens, and the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all plastic lenses; adopting a glass-plastic hybrid structure can effectively reduce costs, correct aberrations, reduce volume, and provide an optical lens product with higher cost performance.

[0078] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens 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 reducing the size of lenses, and better realizing miniaturization of lenses. More specifically, in the optical lens provided by the present invention, the second lens may be a spherical lens, and the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens may be aspherical lenses.

[0079] 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:

[0080]

[0081] 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.

[0082] 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.

[0083] Example 1

[0084] 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, along the optical axis from the object side to the imaging surface S17, a first lens L1, a second lens L2, an aperture ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7 and a filter G1.

[0085] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0086] The second lens L2 has positive refractive power, its object-side surface S3 is convex, and its image-side surface S4 is convex;

[0087] The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is convex;

[0088] The fourth lens L4 has positive refractive power, its object-side surface S7 is convex at the near optical axis, and its image-side surface S8 is convex;

[0089] 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;

[0090] The sixth lens L6 has positive refractive power, its object-side surface S11 is concave, and its image-side surface S12 is convex;

[0091] The seventh lens L7 has negative refractive power, the object-side surface S13 thereof is convex at the near optical axis, and the image-side surface S14 thereof is concave at the near optical axis;

[0092] The object side surface S15 and the image side surface S16 of the filter G1 are both planes;

[0093] The imaging surface S17 is a plane.

[0094] The second lens L2 is a glass spherical lens; the first lens L1, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all plastic aspherical lenses.

[0095] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0096] Table 1-1

[0097]

[0098]

[0099] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0100] Table 1-2

[0101]

[0102] In this embodiment, the field curvature curve, MTF curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 shown.

[0103] Figure 2 The field curvature curve of Example 1 is shown, which represents the field curvature of light on the meridional image plane and the sagittal image plane, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.15mm, indicating that the optical lens 100 can well correct the field curvature.

[0104] Figure 3 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF value of this embodiment is above 0.6 in the whole field of view, and in the range of 0 to 100 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency conditions.

[0105] Figure 4 The axial aberration curve of the present embodiment 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. As can be seen from the figure, the offset of the axial aberration is controlled within ±0.04mm, indicating that the optical lens 100 can better correct the axial aberration.

[0106] Figure 5 The 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 ±2.5 μm, indicating that the optical lens 100 can better correct the vertical chromatic aberration.

[0107] Example 2

[0108] 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.

[0109] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0110] Table 2-1

[0111]

[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 field curvature curve, MTF curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens 200 are respectively as follows: Figure 7 , Figure 8 , Fig. 9 , Fig.10 shown.

[0117] from Figure 7 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.2 mm, indicating that the optical lens 200 can correct the field curvature well.

[0118] from Figure 8 It can be seen that the MTF value of this embodiment is above 0.3 in the entire field of view. In the range of 0 to 100 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view. The optical lens 200 has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0119] from Fig. 9 It can be seen that the offset of the axial aberration is controlled within ±0.04 mm, indicating that the optical lens 200 can correct the axial aberration well.

[0120] from Fig.10 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±3.5μm, indicating that the optical lens 200 can correct the vertical axis chromatic aberration well.

[0121] Example 3

[0122] See also Fig.11 , shown is a schematic diagram of the structure of an optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main differences of this embodiment are: the object side surface S3 of the second lens L2 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0123] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0124] Table 3-1

[0125]

[0126] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0127] Table 3-2

[0128]

[0129]

[0130] In this embodiment, the field curvature curve, MTF curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens 300 are respectively as follows: Fig.12 , Fig.13 , Fig.14 , Fig.15 shown.

[0131] from Fig.12 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 300 can correct the field curvature well.

[0132] from Fig.13 It can be seen that the MTF value of this embodiment is above 0.65 in the entire field of view. In the range of 0 to 100 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view. The optical lens 300 has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0133] from Fig.14 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.

[0134] from Fig.15 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2μm, indicating that the optical lens 300 can correct the vertical axis chromatic aberration well.

[0135] Please refer to Table 4, which shows the optical characteristics corresponding to the above 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 chief 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.

[0136] Table 4

[0137]

[0138]

[0139] Compared with the prior art, the optical lens provided by the present invention has at least the following advantages:

[0140] The optical lens provided by the present invention adopts a seven-piece glass-plastic hybrid structure. Through a specific surface shape setting and a reasonable optical focal length distribution, the structure of the optical lens is relatively compact, and a large field of view of the lens can be achieved. At the same time, it has a large image surface and realizes high-definition imaging. At the same time, it can also reasonably correct the overall aberration of the optical lens, so that the optical lens has a high pixel while effectively shortening the overall length of the optical lens, thereby better meeting the use requirements of miniaturization, large image surface, and wide-angle shooting of drones.

[0141] 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.

[0142] 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, comprising seven lenses, characterized in that: From the object side to the imaging surface along the optical axis, it successively includes: A first lens with negative optical power, whose object side is convex and whose image side is concave; A second lens with positive optical power, whose image side is convex; A third lens with positive optical power, whose object side is convex and whose image side is convex; A fourth lens with positive optical power, whose object side is convex near the optical axis 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 concave and whose image side is convex; A seventh lens with negative optical power, whose object side is convex near the optical axis and whose image side is concave near the optical axis; Wherein, the maximum field of view FOV of the optical lens satisfies: 115° < FOV < 150°; the true image height IH corresponding to the maximum field of view of the optical lens, the maximum field of view FOV of the optical lens and the effective focal length f of the optical lens satisfy: 43° < (f × FOV) / IH < 50°.

2. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.8 < f1 / f < -1.2; the curvature radius R1 of the object side of the first lens and the curvature radius R2 of the image side of the first lens satisfy: 2.5 < R1 / R2 < 5.

3. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.8 < f2 / f < 2.8; the effective focal length f of the optical lens and the curvature radius R4 of the image side of the second lens satisfy: -2 < R4 / f < -0.

5.

4. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.3 < f3 / f < 2; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.7 < f4 / f < 2.

7.

5. The optical lens according to claim 1, characterized in that: The focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: 0.4 < f3 / f4 < 1.

6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.5 < f5 / f < -1; the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -2.5 < f5 / f6 < -1.

7. 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: 0.5 < f6 / f < 0.

85.

8. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -1.2 < f7 / f < -0.

7.

9. The optical lens according to claim 1, characterized in that: The overall optical length TTL of the optical lens and the back focal length BFL of the optical lens satisfy: 0.18 < BFL / TTL < 0.25; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.45 < BFL / f < 0.

6.

10. The optical lens according to claim 1, characterized in that: The focal length f1 of the first lens and the focal length f7 of the seventh lens satisfy: 1.1 < f1 / f7 < 2; the clear aperture DM11 of the object side of the first lens and the clear aperture DM72 of the image side of the seventh lens satisfy: 0.5 < DM11 / DM72 < 0.

65.

11. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 2.2 < IH / f < 3.2; 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: 0.83 < TTL / IH < 0.93.

Images