Optical lens

Abstract

The present invention provides an optical lens having nine lenses, which include, in order from the object side to the imaging surface along the optical axis: a first lens having negative optical power, whose object side surface is concave and whose image side surface is concave; a second lens having positive optical power, whose object side surface is convex; a third lens having positive optical power; a fourth lens having positive optical power, whose object side surface is convex; a fifth lens having negative optical power, whose object side surface is convex and whose image side surface is concave; a sixth lens having positive optical power, whose object side surface is convex and whose image side surface is convex; a seventh lens having negative optical power, whose object side surface is concave; an eighth lens having negative optical power, whose object side surface is concave and whose image side surface is concave; and a ninth lens having positive optical power, whose object side surface is convex. The optical lens provided by the present invention has one or more advantages such as miniaturization, large field of view, large image surface, large aperture, and high imaging quality through specific surface shape matching and reasonable optical power distribution.

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] In the field of modern motion image capture, high-performance portable optical systems are a core requirement. Currently, most action camera lenses on the market use large-aperture, ultra-wide-angle designs to accommodate high-speed motion scenes and extreme environments. However, these traditional optical structures generally suffer from reduced image quality in low-light environments and insufficient dynamic range. Furthermore, to improve image stabilization performance, complex optical compensation mechanisms are often employed, resulting in increased size and weight of the lens module, which not only limits the device's suitability for extreme motion scenes but also significantly increases production and maintenance costs. Furthermore, the increased field of view of the lens makes it difficult to correct for system aberrations and reduces image quality. The lens's relatively small aperture and poor light transmission make it incapable of adapting to darker environments. Furthermore, the existing lens's small imaging target area makes it difficult to meet market demand. Summary of the Invention

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

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

[0005] An optical lens, comprising nine lenses, including the following elements in order from the object side to the imaging surface along the optical axis:

[0006] The first lens has a negative optical power, and its object-side surface is concave and its image-side surface is concave;

[0007] a second lens having positive optical power and a convex object-side surface;

[0008] a third lens having positive optical power;

[0009] a fourth lens element having positive optical power and a convex object-side surface;

[0010] a fifth lens element having negative optical power, whose object-side surface is convex and whose image-side surface is concave;

[0011] a sixth lens element having positive refractive power, whose object-side surface is convex and whose image-side surface is convex;

[0012] a seventh lens element having negative optical power and a concave object-side surface;

[0013] an eighth lens element having negative optical power, whose object-side surface and image-side surface are concave;

[0014] The ninth lens element has positive refractive power and its object-side surface is convex.

[0015] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5 < TTL / f < 6.5; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.1 < TTL / IH < 2.5.

[0016] Further preferably, the maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 60° < FOV / Fno < 70°; the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 5.5 < IH / EPD < 6.5.

[0017] Further preferably, the true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.1 < IH / f < 2.7; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.3 < BFL / f < 0.6.

[0018] Further preferably, the clear aperture d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 0.21 < d1 / (IH / 2) / tan(FOV / 2) < 0.26; the combined focal length f12,34 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f56789 of the fifth lens, the sixth lens, the seventh lens, the eighth lens and the ninth lens satisfy: 0.07 < f1234 / f56789 < 0.72.

[0019] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.7 < f1 / f < -1.5; the curvature radius R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -24 < R1 / f < -2.5; the curvature radius R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: 0.8 < R2 / f < 1.2.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 11 < f3 / f < 32; the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: 0.29 < R5 / R6 < 1.02.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -5.8 < f8 / f < -3.7; the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: -8.5 < R15 / f < -4.3; the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 4.3 < R16 / f < 5.

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f9 of the ninth lens satisfy: 38 < f9 / f < 51; the object-side curvature radius R17 of the ninth lens and the effective focal length f of the optical lens satisfy: 1.5 < R17 / f < 36.

[0023] Further preferably, the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: 0.2 < (R1 + R2) / (R1 - R2) < 1.

[0024] The optical lens provided by the present invention adopts nine lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power distributions, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, enabling the lens to have one or more advantages such as miniaturization, large field angle, large image plane, large aperture, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

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

[0027] Figure 2 is a MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3 is a field curvature curve graph of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 4 is a F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 5 is an axial aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 6 is a lateral chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 7Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

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

[0034] Figure 9 Graph showing the field curvature of the optical lens in Example 2 of the present invention.

[0035] Figure 10 FIG. 4 is a graph showing the F-Tan (Theta) distortion curve of the optical lens in Example 2 of the present invention.

[0036] Figure 11 2 is an axial aberration curve diagram of the optical lens in Example 2 of the present invention.

[0037] Figure 12 Graph showing vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0038] Figure 13 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0039] Figure 14 This is the MTF curve of the optical lens in Example 3 of the present invention.

[0040] Figure 15 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0041] Figure 16 Graph showing the F-Tan (Theta) distortion of the optical lens in Example 3 of the present invention.

[0042] Figure 17 4 is an axial aberration curve diagram of the optical lens in Example 3 of the present invention.

[0043] Figure 18 Graph showing vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0044] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0045] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of 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.

[0046] It should be noted that in this specification, the terms "first," "second," "third," etc., are used solely to distinguish one feature from another and do not limit the features. Thus, the first lens discussed below could also be referred to as the second lens or the third lens without departing from the teachings of the present invention.

[0047] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0048] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0049] 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 preclude 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 list of 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.

[0050] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0051] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this 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.

[0052] The optical lens provided in an embodiment of the present invention comprises nine lenses, which are arranged in order from the object side to the imaging surface along the optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens.

[0053] In some embodiments, the first lens may have negative optical power, with its object-side surface being concave and its image-side surface being concave. The second lens may have positive optical power, with its object-side surface being convex, and its image-side surface being either concave or convex. The third lens may have positive optical power, with its object-side surface being concave or convex, and its image-side surface being either concave or convex. The fourth lens may have positive optical power, with its object-side surface being convex, and its image-side surface being either concave or convex. The fifth lens may have negative optical power, with its object-side surface being convex, and its image-side surface being concave. The sixth lens may have positive optical power, with its object-side surface being convex, and its image-side surface being convex. The seventh lens may have negative optical power, with its object-side surface being concave, and its image-side surface being either concave or convex. The eighth lens may have negative optical power, with its object-side surface being concave, and its image-side surface being concave. The ninth lens may have positive optical power, with its object-side surface being convex, and its image-side surface being either concave or convex.

[0054] In some embodiments, the optical lens may further include an aperture, which may be located between the fourth and fifth lenses. It is understood that the aperture is used to limit the amount of light entering, thereby changing the brightness of the image. Furthermore, when the aperture is located between the fourth and fifth lenses, it can effectively distribute the functions of the first through ninth lenses. For example, the first, second, third, and fourth lenses can be used to receive a greater amount of light, while the fifth through ninth lenses can be used to correct aberrations, thus balancing the structure of the entire optical system. Furthermore, when the aperture is located between the fourth and fifth lenses, it facilitates the correction of aperture aberrations.

[0055] In some embodiments, the optical lens may further include a filter disposed between the ninth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0056] In some embodiments, the fifth lens and the sixth lens can be cemented to form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the decentration 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.

[0057] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5 < TTL / f < 6.5. Meeting the above range can effectively limit the length of the lens and is conducive to the miniaturization of the optical lens. More specifically, 5.2 < TTL / f < 6.08.

[0058] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.1 < TTL / IH < 2.5. Meeting the above range ensures that, with the same total length of the lens, it has a larger image plane, can match a larger-sized imaging chip to achieve high-definition imaging, and better achieves the balance between a small total length and a large image plane of the lens. More specifically, 2.25 < TTL / IH < 2.4.

[0059] In some embodiments, the maximum field angle FOV of the optical lens and the f-number Fno of the optical lens satisfy: 60° < FOV / Fno < 70°. Meeting the above range defines that the optical lens has an appropriate field angle and f-number, can collect light at a large angle, and obtain good imaging quality. More specifically, 65.2° < FOV / Fno < 65.9°.

[0060] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 5.5 < IH / EPD < 6.5. Meeting the above range can increase the width of the light beam entering the optical lens, improve the brightness at the image plane of the optical lens, and avoid the generation of vignetting. More specifically, 5.61 < IH / EPD < 6.24.

[0061] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.1 < IH / f < 2.7. Meeting the above range controls the image height and focal length of the optical lens within a reasonable range, helps the optical lens have the characteristic of a large image plane, and improves the imaging quality. More specifically, 2.3 < IH / f < 2.55.

[0062] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.3 < BFL / f < 0.6. Meeting the above range defines that the optical lens has an appropriate back focus, facilitates the reasonable arrangement of the positions of each lens, and at the same time reduces the processing and assembly difficulty. More specifically, 0.35 < BFL / f < 0.57.

[0063] In some embodiments, the clear aperture d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.21 < d1 / (IH / 2) / tan(FOV / 2) < 0.26. Satisfying the above range can make the front aperture small while satisfying the optical lens with a large field angle and a large image plane.

[0064] In some embodiments, the combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens and the combined focal length f56789 of the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens satisfy: 0.07 < f1234 / f56789 < 0.72. The combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens and the effective focal length f of the optical lens satisfy: 1.3 < f1234 / f < 2.7; the combined focal length f56789 of the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens and the effective focal length f of the optical lens satisfy: 3.5 < f56789 / f < 18. Satisfying the above range is conducive to balancing various aberrations generated by the lens group in front of the aperture and improving the overall imaging quality by reasonably setting the focal lengths of the lens groups before and after the aperture. More specifically, 1.4 < f1234 / f < 2.63; 3.69 < f56789 / f < 17.55.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.7 < f1 / f < -1.5; the curvature radius R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -24 < R1 / f < -2.5; the curvature radius R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: 0.8 < R2 / f < 1.2. Satisfying the above range is conducive to the first lens accommodating a larger angle of light and collecting as much light as possible into the rear optical system by setting the first lens to have a negative refractive power and a double concave shape, increasing the light flux while achieving a large field of view. More specifically, -1.67 < f1 / f < -1.55; -23.15 < R1 / f < -2.7; 0.84 < R2 / f < 1.12.

[0066] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 11 < f3 / f < 32; the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: 0.29 < R5 / R6 < 1.02. Satisfying the above range can make the third lens have an appropriate positive optical power and a meniscus shape, which is conducive to improving the light converging ability of the optical lens and balancing various aberrations generated by the optical lens, thereby improving the imaging quality of the optical lens. More specifically, 11.79 < f3 / f < 31.79.

[0067] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -5.8 < f8 / f < -3.7; the radius of curvature R15 of the object side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -8.5 < R15 / f < -4.3; the radius of curvature R16 of the image side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 4.3 < R16 / f < 5. Meeting the above ranges and setting the eighth lens to have a negative refractive power and a double concave surface type is beneficial to increasing the divergence degree of light, increasing the area of light entering the imaging surface, achieving large target surface imaging of the lens, and improving the imaging quality of the optical lens. More specifically, -5.54 < f8 / f < -3.88; -8.06 < R15 / f < -4.42; 4.45 < R16 / f < 4.88.

[0068] In some embodiments, the effective focal length f of the optical lens and the focal length f9 of the ninth lens satisfy: 38 < f9 / f < 51; the radius of curvature R17 of the object side surface of the ninth lens and the effective focal length f of the optical lens satisfy: 1.5 < R17 / f < 36. Meeting the above ranges can make the eighth lens have a positive optical power and a convex object side surface, control the light trend smoothly, reduce the angle between the chief ray of the edge field of view and the optical axis, and reduce the spot diameter to improve aberration. More specifically, 38.32 < f9 / f < 50.82; 1.59 < R17 / f < 35.71.

[0069] 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: 0.2 < (R1 + R2) / (R1 - R2) < 1. Meeting the above ranges can control the light direction, reduce spherical aberration, correct coma, increase light utilization rate, and improve stability. More specifically, 0.41 < (R1 + R2) / (R1 - R2) < 0.94.

[0070] 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 ninth lens along the optical axis respectively satisfy: 0.49 < ∑CT / TTL < 0.55. Meeting the above ranges can effectively compress the overall length of the optical lens and is beneficial to the structural design and production process of the optical lens.

[0071] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the ninth lens along the optical axis respectively and the effective focal length f of the optical lens satisfy: 2.81 < ΣCT / f < 3.02. Meeting the above ranges can effectively correct the field curvature and distortion of the optical lens and improve the imaging quality of the optical lens.

[0072] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 4.8 < f2 / f < 9. Meeting the above range defines that the second lens has an appropriate positive optical power, which has the effect of converging light rays, reducing the height of peripheral light rays, and is beneficial to reducing the aperture of the rear lens. More specifically, 4.01 < f2 / f < 8.91.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 2.2 < f4 / f < 2.9. Meeting the above range sets the fourth lens to have a positive refractive power, which is beneficial to converging light rays while correcting the field curvature and distortion of the optical lens, and improving the imaging quality of the optical lens. More specifically, 2.32 < f4 / f < 2.8.

[0074] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.9 < f5 / f < -1.2. Meeting the above range can make the fifth lens have an appropriate negative optical power, which can balance various aberrations generated by the optical lens and improve the imaging quality of the optical lens. More specifically, -1.8 < f5 / f < -1.29.

[0075] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.8 < f6 / f < 1; the curvature radius R11 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 0.55 < R11 / f < 0.65; the curvature radius R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -5.7 < R12 / f < -3.3. Meeting the above range defines that the sixth lens has a positive optical power and a suitable surface shape, which is beneficial to light convergence. And the cooperation of the sixth lens with positive optical power and the fifth lens with negative optical power can adjust the optical path difference between different fields of view, improve resolution, and is beneficial to making light enter the rear lens smoothly, further reducing field curvature and correcting off-axis point aberrations of the optical lens. More specifically, 0.86 < f6 / f < 0.95; 0.56 < R11 / f < 0.63; -5.64 < R12 / f < -3.32.

[0076] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -8.2 < f7 / f < -3.6; the curvature radius R13 of the object side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -4 < R13 / f < -2.9. Meeting the above range sets the seventh lens to have a negative refractive power and the object side surface to be concave, which can effectively balance various aberrations generated by the front lens group. More specifically, -7.96 < f7 / f < -4.8; -3.9 < R13 / f < -2.93.

[0077] In some embodiments, the optical lens satisfies the following conditional expressions: 3.7 mm < f < 4.6 mm; 1.5 mm < EPD < 1.8 mm; 20 mm < TTL < 25 mm; 2.2 < Fno < 2.6; 30° < CRA < 40°; 1.3 mm < BFL < 2.4 mm; 150° < FOV < 170°; 9 mm < IH < 11 mm. In the above conditional expressions, 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 chief ray angle of incidence of the optical lens, BFL represents the back focal length of the optical lens, FOV represents the maximum field angle of the optical lens, and IH represents the true image height corresponding to the maximum field angle of the optical lens. Meeting the above ranges, the optical lens has at least one or more advantages such as miniaturization, large image plane, large aperture, and large field angle. More specifically, 3.93 mm < f < 4.34 mm; 1.59 mm < EPD < 1.79 mm; 22.54 mm < TTL < 23.88 mm; 2.42 < Fno < 2.46; 31.39° < CRA < 36.86°; 1.45 mm < BFL < 2.21 mm; 159° < FOV < 161°; 9.9 mm < IH < 10.1 mm.

[0078] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. Additionally, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The optical lens of the present invention adopts a lens structure with nine glass-plastic hybrid combinations, which can improve the thermal stability performance. Specifically, the seventh lens uses a plastic lens; the eighth lens uses a plastic or glass lens; the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the ninth lens are all glass lenses; adopting a glass-plastic hybrid structure can effectively reduce costs, correct aberrations, reduce the volume, and provide an optical lens product with higher cost performance.

[0079] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth 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, in the optical lens provided by the present invention, the first lens, the second lens, the seventh lens, the eighth lens, and the ninth lens can adopt aspherical lenses, and the third lens, the fourth lens, the fifth lens, and the sixth lens can adopt spherical lenses.

[0080] In various embodiments of the present invention, when the lens is an aspheric lens, the shapes of the aspheric surfaces of the optical lens satisfy the following equations:

[0081] ;

[0082] Where z is the distance between the surface and the vertex 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, and B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients, respectively.

[0083] The present invention is further illustrated below with reference to several embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens vary; for details, please refer to the parameter tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the present invention is not limited thereto. Any other changes, substitutions, combinations, or simplifications that do not deviate from the novelties of the present invention shall be considered equivalent replacements and are included within the scope of protection of the present invention.

[0084] Example 1

[0085] See also Figure 1 , shown is a schematic structural diagram of the optical lens 100 provided in Example 1 of the present invention. The optical lens 100 includes, in order from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9 and a filter G1.

[0086] The first lens L1 has negative refractive power, its object-side surface S1 is concave, and its image-side surface S2 is concave;

[0087] The second lens L2 has positive refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave;

[0088] The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is concave;

[0089] The fourth lens L4 has positive refractive power, its object-side surface S7 is convex, and its image-side surface S8 is convex;

[0090] The fifth lens L5 has negative refractive power, its object-side surface S9 is convex, and its image-side surface is concave;

[0091] The sixth lens L6 has positive refractive power, its object-side surface is convex, and its image-side surface S11 is convex;

[0092] The fifth lens L5 and the sixth lens L6 form a cemented lens group with positive refractive power. That is, the cemented surface between the image-side surface of the fifth lens L5 and the object-side surface of the sixth lens L6 is S10.

[0093] The seventh lens L7 has negative refractive power, its object-side surface S12 is concave, and its image-side surface S13 is convex;

[0094] The eighth lens L8 has negative refractive power, its object-side surface S14 is concave, and its image-side surface S15 is concave;

[0095] The ninth lens L9 has positive refractive power, its object-side surface S16 is convex, and its image-side surface S17 is concave;

[0096] The object-side surface S18 and the image-side surface S19 of the filter G1 are both flat surfaces;

[0097] The imaging surface S20 is a plane.

[0098] The seventh lens L7 and the eighth lens L8 are plastic aspherical lenses; the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are glass spherical lenses; and the first lens L1, the second lens L2, and the ninth lens L9 are glass aspherical lenses.

[0099] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0100] Table 1-1

[0101]

[0102] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0103] Table 1-2

[0104]

[0105] In this embodiment, the MTF curve, field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens 100 are shown as follows: Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 and Figure 6 shown.

[0106] Figure 2The MTF (Modulation Transfer Function) curve for Example 1 is shown. It represents the degree of lens modulation at different spatial frequencies across the field of view. The horizontal axis represents spatial frequency (lp / mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF value of this example is consistently above 0.25 across the entire field of view. Within the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating excellent imaging quality and detail resolution at both low and high frequencies.

[0107] Figure 3 The field curvature curves for Example 1 are shown, representing the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: degrees). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within ±0.02mm, demonstrating that the optical lens is capable of effectively correcting field curvature.

[0108] Figure 4 The F-Tan (Theta) distortion curve for Example 1 shows the F-Tan (Theta) distortion of light of different wavelengths at different image heights on the imaging surface. The horizontal axis represents the F-Tan (Theta) distortion value (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Tan (Theta) distortion of the optical lens is controlled within a range of -80% to 0, and the image compression in the edge angle area is relatively smooth, effectively improving the clarity of the expanded image.

[0109] Figure 5 The following figure shows the axial aberration curve of the optical lens 100 in this embodiment, which shows 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 -0.01mm to 0.02mm, indicating that the optical lens 100 is able to effectively correct the axial aberration.

[0110] Figure 6 A graph showing the vertical chromatic aberration of the optical lens 100 in this embodiment shows the chromatic aberration of each wavelength relative to the central wavelength (0.522 μm) at different image heights on the imaging plane. The horizontal axis represents the vertical chromatic aberration of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the graph, the vertical chromatic aberration for both the longest and shortest wavelengths is within 0 to 3 μm, demonstrating that the optical lens is capable of effectively correcting chromatic aberration.

[0111] Example 2

[0112] See also Figure 7, shown is a schematic structural diagram of an optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image-side surface S4 of the second lens element L2 is convex; the object-side surface S5 of the third lens element L3 is concave; the image-side surface S6 of the third lens element L3 is convex; the image-side surface S13 of the seventh lens element L7 is concave; the eighth lens element L8 is a glass aspherical lens; and 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 200 in Example 2 are shown in Table 2-1.

[0114] Table 2-1

[0115]

[0116] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0117] Table 2-2

[0118]

[0119] In this embodiment, the MTF curve, field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens 200 are shown as follows: Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 and Figure 12 shown.

[0120] from Figure 8 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, achieving good imaging quality and detail resolution in both low-frequency and high-frequency conditions.

[0121] from Figure 9 It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.01mm, indicating that the optical lens can correct the field curvature well.

[0122] from Figure 10 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -80% ~ 0, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the expanded image.

[0123] from Figure 11 It can be seen that the offset of axial aberration is controlled within -0.01mm~0.02mm, which shows that the optical lens can correct axial aberration well.

[0124] from Figure 12 It can be seen that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -0.5μm~1.5μm, indicating that the optical lens can correct chromatic aberration well.

[0125] Example 3

[0126] See also Figure 13 , shown is a schematic structural diagram of an optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image-side surface S4 of the second lens element L2 is convex; the object-side surface S5 of the third lens element L3 is concave; the image-side surface S6 of the third lens element L3 is convex; the image-side surface S8 of the fourth lens element L4 is concave; and the image-side surface S17 of the ninth lens element L9 is convex; and the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0127] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0128] Table 3-1

[0129]

[0130] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0131] Table 3-2

[0132]

[0133] In this embodiment, the MTF curve, field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens 300 are shown as follows: Figure 14 、 Figure 15 、 Figure 16 、 Figure 17 and Figure 18 shown.

[0134] from Figure 14 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, achieving good imaging quality and detail resolution in both low-frequency and high-frequency conditions.

[0135] from Figure 15 It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.02mm, indicating that the optical lens can correct the field curvature well.

[0136] from Figure 16It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -80% ~ 0, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the expanded image.

[0137] from Figure 17 It can be seen that the offset of axial aberration is controlled within -0.01mm~0.02mm, which shows that the optical lens can correct axial aberration well.

[0138] from Figure 18 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within 0~2μm, indicating that the optical lens can correct chromatic aberration well.

[0139] Please refer to Table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, real image height IH corresponding to the maximum field of view angle, maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0140] Table 4

[0141]

[0142] In summary, the optical lens provided by the present invention uses nine lenses with specific optical powers. Through the combination of specific surface shapes and reasonable optical power distribution, it is possible to improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, so that the lens has one or more advantages such as miniaturization, a large field of view, a large image surface, a large aperture, and high imaging quality.

[0143] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0144] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An optical lens, comprising nine lenses, characterized in that: It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with a negative optical power, whose object side is concave and whose image side is concave; A second lens with a positive optical power, whose object side is convex; A third lens with a positive optical power; A fourth lens with a positive optical power, whose object side is convex; A fifth lens with a negative optical power, whose object side is convex and whose image side is concave; A sixth lens with a positive optical power, whose object side is convex and whose image side is convex; A seventh lens with a negative optical power, whose object side is concave; An eighth lens with a negative optical power, whose object side is concave and whose image side is concave; A ninth lens with a positive optical power, whose object side is convex; The maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 60° < FOV / Fno < 70°.

2. The optical lens according to claim 1, wherein: The overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5 < TTL / f < 6.5; the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.1 < TTL / IH < 2.

5.

3. The optical lens according to claim 1, wherein: The maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 65.2° < FOV / Fno < 65.9°; the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 5.5 < IH / EPD < 6.

5.

4. The optical lens according to claim 1, wherein: The true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.1 < IH / f < 2.7; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.3 < BFL / f < 0.

6.

5. The optical lens according to claim 1, wherein: The clear aperture diameter d1 of the object side of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 0.21 < d1 / (IH / 2) / tan(FOV / 2) < 0.26; the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f56789 of the fifth lens, the sixth lens, the seventh lens, the eighth lens and the ninth lens satisfy: 0.07 < f1234 / f56789 < 0.

72.

6. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.7 < f1 / f < -1.5; the curvature radius R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: -24 < R1 / f < -2.5; the curvature radius R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: 0.8 < R2 / f < 1.

2.

7. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 11 < f3 / f < 32; 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: 0.29 < R5 / R6 < 1.

02.

8. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -5.8 < f8 / f < -3.7; the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: -8.5 < R15 / f < -4.3; the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 4.3 < R16 / f < 5.

9. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f9 of the ninth lens satisfy: 38 < f9 / f < 51; the object-side curvature radius R17 of the ninth lens and the effective focal length f of the optical lens satisfy: 1.5 < R17 / f < 36.

10. The optical lens according to claim 1, wherein: The object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: 0.2 < (R1 + R2) / (R1 - R2) < 1.

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