Optical lens

Abstract

The present invention provides an optical lens, which has a total of seven lenses. Along the optical axis from the object side to the imaging surface, it sequentially includes: a first lens with a negative optical power, whose object side is convex and whose image side is concave; a second lens with a positive optical power, whose object side is convex and whose image side is flat or concave; a third lens with a positive optical power, both of whose object side and image side are convex; a fourth lens with a negative optical power; a fifth lens with a negative optical power, whose object side is concave and whose image side is convex; a sixth lens with a negative optical power, whose image side is concave near the optical axis; a seventh lens with a positive optical power, whose object side is convex near the optical axis and whose image side is convex; 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: 2.8 < IH / f < 3.5. The optical lens provided by the present invention has at least one or more advantages such as being thin and light, having a large field of view angle, and having a high pixel count.

Description

Technical Field

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

[0002] With the continuous upgrading of drones, consumers have higher and higher requirements for drone functions. Ultra-high pixels, large apertures, and wide-angle shooting have become the main development trends of drones. In order to pursue high-quality imaging, mainstream drones currently use all-glass lenses, and the number of lenses has been upgraded from 5 to 6 to 7 to 8 to correct the light path. However, due to the constraints of glass lenses, the weight and volume of glass lenses are difficult to reduce, and all-glass lenses have encountered a bottleneck period. Since plastic lenses are thinner and have good plasticity, lenses using plastic lenses can be effectively thinned and lightened. At the same time, combined with the advantages of plastic lenses, large field of view shooting can be achieved while ensuring the amount of light entering the optical lens and the clarity of the image. It is expected to be applied in high-end drones and is the development trend of drone lenses in the future. However, how to better achieve the large field of view and high pixel performance of the lens is still an urgent problem to be solved. Summary of the invention

[0003] In view of the above problems, an object of the present invention is to provide an optical lens having at least one or more advantages such as lightness and thinness, a large field of view, and a high pixel count.

[0004] The present invention provides an optical lens, which comprises seven lenses in total, and includes the following lenses in order from the object side to the imaging surface along the optical axis:

[0005] The first lens has a negative optical power, the object side surface of which is convex, and the image side surface of which is concave;

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

[0007] The third lens has positive refractive power, and both the object side surface and the image side surface are convex;

[0008] a fourth lens having negative optical power;

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

[0010] A sixth lens element having negative optical power, whose image side surface is concave at the near optical axis;

[0011] The seventh lens has positive refractive power, its object side surface is convex at the near optical axis, and its image side surface is convex;

[0012] The effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy the following conditions: 2.8 <IH / f<3.5。

[0013] Further preferably, 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: 7.4 < IH / EPD < 9.1.

[0014] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.4 < f1 / f < -0.9.

[0015] Further preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -4.7 < f6 / f < -1.6; the image-side curvature radius R12 of the sixth lens and the object-side curvature radius R13 of the seventh lens satisfy: 0.9 < R12 / R13 < 4.7.

[0016] Further preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 0.5 < f7 / f < 0.9; the effective focal length f of the optical lens and the object-side curvature radius R13 of the seventh lens satisfy: 0.35 < R13 / f < 1.

[0017] Further preferably, the combined focal length f12 of the first lens and the second lens and the combined focal length f34567 of the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfy: -7.4 < f12 / f34567 < -1.4.

[0018] Further preferably, the effective focal length f of the optical lens and the object-side curvature radius R1 of the first lens satisfy: 0.7 < R1 / f < 1.3; the effective focal length f of the optical lens and the image-side curvature radius R2 of the first lens satisfy: 0.2 < R2 / f < 0.4.

[0019] Further preferably, the object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -1.7 < R13 / R14 < -0.5; the focal length f7 of the seventh lens and the object-side curvature radius R13 of the seventh lens satisfy: 0.6 < R13 / f7 < 1.4.

[0020] Further preferably, the object-side sagittal height Sag1 of the first lens and the object-side clear aperture diameter d1 of the first lens satisfy: 0.15 < Sag1 / d1 < 0.25; the image-side sagittal height Sag2 of the first lens and the image-side clear aperture diameter d2 of the first lens satisfy: 0.45 < Sag2 / d2 < 0.75.

[0021] Further preferably, the object side curvature radius R1 of the first lens, the image side curvature radius R2 of the first lens and the center thickness CT1 of the first lens satisfy: 1.2 <R1 / (R2+CT1)<1.5。

[0022] Compared with the prior art, the optical lens provided by the present invention has a relatively compact structure through a specific surface shape setting and a reasonable optical focal length distribution, and at the same time has a large field of view and a high imaging quality, and can achieve high-definition imaging. In addition, 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 drones such as lightweight, high image quality, and wide-angle shooting. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0024] Figure 1 Schematic diagram of the structure of the optical lens in Example 1 of the present invention.

[0025] Figure 2 It is a field curvature curve diagram of the optical lens in Example 1 of the present invention.

[0026] Figure 3 Graph showing the axial aberration of the optical lens in Example 1 of the present invention.

[0027] Figure 4 Graph showing the vertical axis chromatic aberration of the optical lens in Example 1 of the present invention.

[0028] Figure 5 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0029] Figure 6 It is a field curvature curve diagram of the optical lens in Example 2 of the present invention.

[0030] Figure 7 Graph showing the axial aberration of the optical lens in Embodiment 2 of the present invention.

[0031] Figure 8 Graph showing the vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0032] Fig. 9 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0033] Fig.10 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0034] Fig.11Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0035] Fig.12 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0036] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] In some embodiments, the first lens may have a negative optical power, its object side surface is convex, and its image side surface is concave. The second lens may have a positive optical power, its object side surface is convex, and its image side surface is flat or concave. The third lens may have a positive optical power, and its object side surface and image side surface are both convex. The fourth lens may have a negative optical power, its object side surface may be concave or convex, and its image side surface may be concave or convex. The fifth lens may have a negative optical power, its object side surface is concave, and its image side surface is convex. The sixth lens may have a negative optical power, its object side surface may be concave or convex, and its image side surface is concave at the near optical axis. The seventh lens may have a positive optical power, its object side surface is convex at the near optical axis, and its image side surface is convex.

[0046] In some embodiments, the optical lens may further include an aperture, which may be located between the second lens and the third lens. It is understandable that the aperture is used to limit the amount of light entering to change the brightness of the image. In addition, when the aperture is located between the second lens and the third lens, the aperture can reasonably distribute the effects of the first lens to the seventh lens. For example, the first lens and the second lens can be used to receive light to a greater extent, and the third lens to the seventh lens can be used to correct the aberration, which is conducive to balancing the structure of the entire optical system. In addition, when the aperture is located between the second lens and the third lens, it is convenient to correct the aperture aberration.

[0047] In some embodiments, the optical lens may further include a filter, which is disposed between the seventh 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.

[0048] 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: 2.8 < IH / f < 3.5. Meeting the above range is beneficial to increasing the imaging area of the optical lens to offset the picture compression caused by the marginal field distortion brought by the large field of view angle, thereby improving the imaging quality of the marginal field of view. More specifically, 3.1 < IH / f < 3.3.

[0049] 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: 7.4 < IH / EPD < 9.1. Meeting the above range can increase the width of the light beam incident on the optical lens, so that the brightness of the optical lens at the image plane is improved and vignetting is avoided. More specifically: 8.2 < IH / EPD < 8.4.

[0050] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.4 < f1 / f < -0.9. Meeting the above range, by reasonably setting the focal length of the first lens, it is beneficial to slow down the change degree of the refraction angle of the incident light, avoid excessive aberration caused by too strong refraction change, and at the same time help more light enter the rear optical system, increasing the field of view angle of the lens and improving the overall imaging quality. More specifically, -1.3 < f1 / f < -1.

[0051] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -4.7 < f6 / f < -1.6; the curvature radius R12 of the image side surface of the sixth lens and the curvature radius R13 of the object side surface of the seventh lens satisfy: 0.9 < R12 / R13 < 4.7. Meeting the above range helps to reduce the aberration of the optical lens, and at the same time is beneficial to increasing the field of view angle and imaging area. More specifically, -4.3 < f6 / f < -1.8; 0.9 < R12 / R13 < 4.3.

[0052] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 0.5 < f7 / f < 0.9; the effective focal length f of the optical lens and the curvature radius R13 of the object side surface of the seventh lens satisfy: 0.35 < R13 / f < 1. Meeting the above range, by reasonably setting the focal length of the seventh lens and the surface shape of the object side surface of the seventh lens, it is beneficial to adjust the light focusing position, improve the light converging ability of the system, and better realize the miniaturization of the lens. More specifically, 0.5 < f7 / f < 0.8; 0.44 < R13 / f < 0.91.

[0053] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f34567 of the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfy: -7.4 < f12 / f34567 < -1.4. Meeting the above range and controlling the lens groups before and after the diaphragm of the optical lens to have appropriate focal lengths can effectively correct the aberrations generated by the lens groups before and after the diaphragm and improve the imaging quality of the optical lens. More specifically, -6.9 < f12 / f34567 < -1.4.

[0054] In some embodiments, the effective focal length f of the optical lens and the curvature radius R1 of the object side surface of the first lens satisfy: 0.7 < R1 / f < 1.3; the effective focal length f of the optical lens and the curvature radius R2 of the image side surface of the first lens satisfy: 0.2 < R2 / f < 0.4. Meeting the above range and reasonably setting the surface shape of the first lens can make the incident light entering the first lens have appropriate incident and exit angles, which is beneficial to increasing the field of view angle of the lens while reducing the outer diameter of the lens and maintaining the miniaturization of the head of the system. More specifically, 0.83 < R1 / f < 1.18; 0.29 < R2 / f < 0.38.

[0055] In some embodiments, the curvature radius R13 of the object side surface of the seventh lens and the curvature radius R14 of the image side surface of the seventh lens satisfy: -1.7 < R13 / R14 < -0.5; the focal length f7 of the seventh lens and the curvature radius R13 of the object side surface of the seventh lens satisfy: 0.6 < R13 / f7 < 1.4. Meeting the above range and reasonably defining the shapes of the object side surface and the image side surface of the seventh lens is beneficial to the correction of the aberrations of the optical lens. More specifically, -1.6 < R13 / R14 < -0.5; 0.7 < R13 / f7 < 1.3.

[0056] In some embodiments, the sagittal height Sag1 of the clear aperture of the object side surface of the first lens and the clear aperture d1 of the object side surface of the first lens satisfy: 0.15 < Sag1 / d1 < 0.25; the sagittal height Sag2 of the clear aperture of the image side surface of the first lens and the clear aperture d2 of the image side surface of the first lens satisfy: 0.45 < Sag2 / d2 < 0.75. Meeting the above range can effectively improve various aberrations in the marginal field of view of the optical lens and enhance the imaging quality of the marginal field of view of the optical lens. More specifically, 0.16 < Sag1 / d1 < 0.2; 0.51 < Sag2 / d2 < 0.69.

[0057] In some embodiments, the radius of curvature R1 of the object side surface of the first lens, the radius of curvature R2 of the image side surface of the first lens, and the central thickness CT1 of the first lens satisfy: 1.2 < R1 / (R2 + CT1) < 1.5. Meeting the above range is conducive to lens processing and improving the yield by reasonably setting the relationship between the surface shape and thickness of the first lens. More specifically, 1.29 < R1 / (R2 + CT1) < 1.39.

[0058] In some embodiments, the effective focal length f of the optical lens and the overall optical length TTL satisfy: 2.6 < TTL / f < 3.3. Meeting the above range is conducive to realizing the miniaturization of the lens. More specifically, 2.8 < TTL / f < 3.1.

[0059] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.45 < BFL / f < 0.85. Meeting the above range defines that the optical lens has an appropriate back focus, facilitating the reasonable arrangement of the positions of the lenses and reducing the processing and assembly difficulty. More specifically, 0.51 < BFL / f < 0.79.

[0060] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV, and the true image height IH corresponding to the maximum field of view satisfy: 38° < (FOV × f) / IH < 48°. Meeting the above conditional formula is conducive to achieving the balance between the large field of view and large target surface imaging of the optical lens by reasonably restricting the relationship between the focal length, field of view, and image height of the optical lens. More specifically, 42° < (FOV × f) / IH < 45°.

[0061] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.3 < f2 / f < 4.4. Meeting the above range defines that the second lens has an appropriate positive optical power, which is conducive to the convergence of light, enabling the light entering the system from the front to smoothly enter the rear optical system and making the light trend smoother. More specifically, 1.4 < f2 / f < 4.1.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.5 < f3 / f < 1.2. Meeting the above range is conducive to further converging light, reducing the difficulty of correcting the marginal field distortion, and improving the overall imaging quality. More specifically, 0.5 < f3 / f < 1.1.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -4.1 < f4 / f < -1.7. By reasonably controlling the focal length of the fourth lens within the above range, the aberration generated at the front end of the lens can be effectively corrected, improving the imaging quality of the lens. More specifically, -3.9 < f4 / f < -1.8.

[0064] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.4 < f5 / f < -1. By reasonably controlling the focal length of the fifth lens within the above range, it helps to increase the imaging area and improve the imaging quality. More specifically, -1.3 < f5 / f < -1.

[0065] In some embodiments, the effective focal length f of the optical lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: 0.35 < R12 / f < 4.25. By reasonably defining the shape of the image side surface of the sixth lens within the above range, it is beneficial to the correction of the aberration of the optical lens. More specifically, 0.41 < R12 / f < 3.87.

[0066] In some embodiments, the focal length f6 of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: -1 < R12 / f6 < -0.1. By adjusting the surface shape of the image side surface of the sixth lens within the above range, it is beneficial to strengthen the correction of higher-order aberrations. More specifically, -0.91 < R12 / f6 < -0.21.

[0067] In some embodiments, 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: 1.7 < (R1 + R2) / (R1 - R2) < 2.3. By satisfying the above range, the angle between the incident light and the object side surface of the first lens can be reduced simultaneously, achieving the purpose of effectively reducing the working aperture of the first lens and avoiding excessive aperture of the rear-end lens of the optical lens caused by light divergence.

[0068] In some embodiments, the radius of curvature R6 of the image side surface of the third lens and the radius of curvature R7 of the object side surface of the fourth lens satisfy: -3.7 < (R6 - R7) / (R6 + R7) < -0.8. By reasonably controlling the incident angle of light between the third lens and the fourth lens within the above range, the ghost energy of light reflection on the object side surface of the fourth lens can be reduced. More specifically, -3.5 < (R6 - R7) / (R6 + R7) < -0.9.

[0069] 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: -0.4 < (R13 + R14) / (R13 - R14) < 0.3. By satisfying the above range and reasonably defining the shapes of the object side surface and the image side surface of the seventh lens, the seventh lens can have an appropriate surface shape, effectively improving the field curvature and aberration and enhancing the imaging quality. More specifically, -0.31 < (R13 + R14) / (R13 - R14) < 0.23.

[0070] In some embodiments, the sagittal height Sag13 of the clear aperture of the object side surface of the seventh lens and the clear aperture diameter d13 of the object side surface of the seventh lens satisfy: -0.3 < Sag13 / d13 < -0.1. By satisfying the above range, various aberrations of the edge field of view of the optical lens can be effectively improved, and the imaging quality of the edge field of view of the optical lens can be enhanced. More specifically, -0.28 < Sag13 / d13 < -0.11.

[0071] 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 seventh lens along the optical axis satisfy: 1.9 < TTL / ∑CT < 2.7. By satisfying the above range and reasonably configuring the overall optical length of the optical lens and the sum of the thicknesses of each lens, it helps to achieve high pixel characteristics and improve the imaging quality of the optical lens. More specifically, 2.1 < TTL / ∑CT < 2.47.

[0072] In some embodiments, the central thickness CT1 of the first lens and the central thickness CT2 of the second lens satisfy: 1.7 < CT1 / CT2 < 2.7. By satisfying the above range and reasonably distributing the central thicknesses of the first and second lenses, while meeting the requirements of assembly stability, the assembly deformation and assembly difficulty of the lenses can be reduced, and at the same time, the structure of the lens is made more compact, which is conducive to realizing the miniaturization of the lens. More specifically, 1.8 < CT1 / CT2 < 2.5.

[0073] In some embodiments, the optical lens satisfies the conditional formula: 3.4 mm < f < 4.2 mm, 130° < FOV < 150°, 1.3 mm < EPD < 1.7 mm, 10.1 mm < TTL < 12.6 mm, 2.4 < Fno < 2.8, 10.4 mm < IH < 13.6 mm, 35.1° < CRA < 44.1°, 1.7 mm < BFL < 3.4 mm, where f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the principal ray incident angle at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least the characteristics of a large field of view angle, a relatively large target surface, and miniaturization. Preferably, 3.76 mm < f < 3.94 mm, 134° < FOV < 142°, 1.4 mm < EPD < 1.6 mm, 11.2 mm < TTL < 11.6 mm, 2.5 < Fno < 2.7, 11.8 mm < IH < 12.2 mm, 38.9° < CRA < 40.1°, 1.9 mm < BFL < 3.1 mm.

[0074] In some embodiments, all seven lenses in the optical lens can be made of plastic lenses or adopt a structure with a combination of glass and plastic materials. Preferably, the optical lens of the present invention adopts a combination structure of seven lenses with a combination of glass and plastic, 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 also achieve a reasonable balance of miniaturization, high pixel count, thinness, lightness, and wide viewing 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 combination structure of glass and plastic can effectively reduce costs, correct aberrations, reduce volume, and provide an optical lens product with higher cost performance.

[0075] In some embodiment modes, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the second lens in the optical lens provided by the present invention can adopt a spherical lens or an aspherical lens, and the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens can adopt aspherical lenses.

[0076] 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:

[0077] ;

[0078] 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.

[0079] 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.

[0080] Example 1

[0081] See also Figure 1 , which is a schematic diagram of the structure of the optical lens 100 provided in Embodiment 1 of the present invention, wherein 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, 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.

[0082] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0083] The second lens L2 has positive refractive power, its object side surface S3 is convex, and its image side surface S4 is flat;

[0084] The third lens L3 has positive refractive power, and its object-side surface S5 and image-side surface S6 are both convex;

[0085] The fourth lens L4 has negative refractive power, its object-side surface S7 is convex at the near optical axis, and its image-side surface S8 is concave;

[0086] The fifth lens L5 has negative refractive power, its object-side surface S9 is concave, and its image-side surface S10 is convex;

[0087] The sixth lens L6 has negative refractive power, an object-side surface S11 thereof is convex at the near optical axis, and an image-side surface S12 thereof is concave at the near optical axis;

[0088] The seventh lens L7 has positive refractive power, its object-side surface S13 is convex at the near optical axis, and its image-side surface S14 is convex;

[0089] The object side surface S15 and the image side surface S16 of the filter G1 are both planes;

[0090] The imaging surface S17 is a plane.

[0091] 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.

[0092] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0093] Table 1-1

[0094]

[0095] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0096] Table 1-2

[0097]

[0098] In this embodiment, the field curvature curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 shown.

[0099] Figure 2 The field curvature curve of Example 1 is shown, which indicates the degree of curvature of light on the meridional image plane and the sagittal image plane, with the horizontal axis indicating the offset (unit: mm) and the vertical axis indicating the half 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 ±0.2 mm, indicating that the optical lens 100 can well correct the field curvature.

[0100] Figure 3 The axial aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the offset of the axial aberration is controlled within ±0.03mm, indicating that the optical lens 100 can correct the axial aberration well.

[0101] Figure 4The vertical chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.56 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 100 can better correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0102] Example 2

[0103] See also Figure 5 , shown is a schematic diagram of the structure of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main differences of this embodiment are: the object side surface S7 of the fourth lens L4 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0104] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0105] Table 2-1

[0106]

[0107] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0108] Table 2-2

[0109]

[0110] In this embodiment, the field curvature curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens 200 are respectively as follows: Figure 6 , Figure 7 , Figure 8 As shown. Figure 6 It can be seen from FIG. 1 that the field curvature is controlled within ±0.2 mm, indicating that the field curvature of the optical lens 200 is well corrected; Figure 7 It can be seen from FIG. 1 that the offset of the axial aberration is within ±0.03 mm, indicating that the axial aberration of the optical lens 200 is well corrected; Figure 8 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the vertical axis chromatic aberration of the optical lens 200 is well corrected.

[0111] Example 3

[0112] See also Fig. 9, shown is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main differences of this embodiment are: the second lens L2 is a glass aspherical lens; the image side surface S4 of the second lens L2 is a concave surface at the near optical axis; the object side surface S7 of the fourth lens L4 is a concave surface; the image side surface S8 of the fourth lens L4 is a convex surface; the object side surface S11 of the sixth lens L6 is a concave surface; 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 300 in Example 3 are shown in Table 3-1.

[0114] Table 3-1

[0115]

[0116] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0117] Table 3-2

[0118]

[0119] In this embodiment, the field curvature curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens 300 are respectively as follows: Fig.10 , Fig.11 , Fig.12 As shown. Fig.10 It can be seen from FIG. 1 that the field curvature is controlled within ±0.1 mm, indicating that the field curvature of the optical lens 300 is well corrected; Fig.11 It can be seen from FIG. 1 that the offset of the axial aberration is within ±0.04 mm, indicating that the axial aberration of the optical lens 300 is well corrected; Fig.12 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 vertical axis chromatic aberration of the optical lens 300 is well corrected.

[0120] 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 maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0121] Table 4

[0122]

[0123] Compared with the prior art, the optical lens provided by the present invention has at least the following advantages:

[0124] (1) A balance between high pixel and lightness and thinness can be achieved. Since plastic lenses are lighter and thinner, the optical lens provided by the present invention adopts a glass-plastic hybrid structure of one glass lens and six plastic lenses, achieving a balance between high pixel and lightness and thinness of the optical lens.

[0125] (2) A large field of view and a short total length can be achieved. The optical lens of the present invention can achieve large-angle shooting, realize the miniaturization of the optical lens, and meet the use requirements of high-quality images and wide-angle shooting of drones.

[0126] To sum up, 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, which can achieve a large field of view of the lens, while having a high imaging quality and achieving 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, better meeting the use requirements of lightweight, high image quality, and wide-angle shooting of drones.

[0127] 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.

[0128] 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 seven lenses in total, characterized in that, along the optical axis from the object side to the imaging surface, it successively includes: a first lens with a negative optical power, whose object side is convex and whose image side is concave; a second lens with a positive optical power, whose object side is convex and whose image side is flat or concave; a third lens with a positive optical power, whose object side and image side are both convex; a fourth lens with a negative optical power; a fifth lens with a negative optical power, whose object side is concave and whose image side is convex; a sixth lens with a negative optical power, whose image side is concave near the optical axis; a seventh lens with a positive optical power, whose object side is convex near the optical axis and whose image side is convex; wherein, 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: 2.8 < IH / f < 3.

5.

2. The optical lens according to claim 1, characterized in that, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 7.4 < IH / EPD < 9.

1.

3. 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: -1.4 < f1 / f < -0.

9.

4. 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: -4.7 < f6 / f < -1.6; the curvature radius R12 of the image side of the sixth lens and the curvature radius R13 of the object side of the seventh lens satisfy: 0.9 < R12 / R13 < 4.

7.

5. 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: 0.5 < f7 / f < 0.9; the effective focal length f of the optical lens and the curvature radius R13 of the object side of the seventh lens satisfy: 0.35 < R13 / f < 1.

6. The optical lens according to claim 1, characterized in that, the combined focal length f12 of the first lens and the second lens and the combined focal length f34567 of the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens satisfy: -7.4 < f12 / f34567 < -1.

4.

7. The optical lens according to claim 1, characterized in that, the effective focal length f of the optical lens and the curvature radius R1 of the object side of the first lens satisfy: 0.7 < R1 / f < 1.3; the effective focal length f of the optical lens and the curvature radius R2 of the image side of the first lens satisfy: 0.2 < R2 / f < 0.

4.

8. The optical lens according to claim 1, characterized in that, the curvature radius R13 of the object side of the seventh lens and the curvature radius R14 of the image side of the seventh lens satisfy: -1.7 < R13 / R14 < -0.5; the focal length f7 of the seventh lens and the curvature radius R13 of the object side of the seventh lens satisfy: 0.6 < R13 / f7 < 1.

4.

9. The optical lens according to claim 1, characterized in that, the sagittal height Sag1 of the clear aperture on the object side of the first lens and the clear aperture diameter d1 of the object side of the first lens satisfy: 0.15 < Sag1 / d1 < 0.25; the sagittal height Sag2 of the clear aperture on the image side of the first lens and the clear aperture diameter d2 of the image side of the first lens satisfy: 0.45 < Sag2 / d2 < 0.

75.

10. The optical lens according to claim 1, characterized in that, the radius of curvature R1 of the object side of the first lens, the radius of curvature R2 of the image side of the first lens and the central thickness CT1 of the first lens satisfy: 1.2 < R1 / (R2 + CT1) < 1.5.

Images