Optical lens

Abstract

The present invention provides an optical lens having a total of six 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 and whose image side surface is concave; a third lens having positive optical power, whose object side surface is convex; a fourth lens having positive optical power, whose object side surface is concave and whose image side surface is convex; a fifth lens having negative optical power; and a sixth lens having positive optical power, whose object side surface is convex and whose image side surface is convex. The optical lens provided by the present invention can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, so that the lens has one or more advantages such as miniaturization, large target surface, large aperture, large field of view, and high imaging quality.

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] As people's requirements for driving experience continue to increase, automotive optical lenses are increasingly used in intelligent driving, and the status of automotive optical lenses in the automotive-related industries continues to improve.

[0003] An electronic rearview mirror is an indirect vision device that uses a system consisting of cameras and monitors to obtain a specified field of view. It includes electronic equipment such as high-definition cameras, digital visual processing systems, safety systems, and liquid crystal displays, and is a new type of rearview mirror that can replace traditional rearview mirrors. Electronic rearview mirrors are generally designed with a main lens and a wide-angle lens. The images are presented on the display screen, which can provide a wider field of view, eliminate blind spots, help drivers better understand their surroundings, and reduce the occurrence of accidents. In addition to requiring the lens of existing electronic rearview mirrors to be thin and short in appearance and have high pixel and high resolution characteristics, it is also required that the optical lens can produce clear images under low illumination conditions. Therefore, it is necessary to develop an optical lens with good imaging effects. Summary of the Invention

[0004] 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.

[0005] The technical solution adopted in the present invention is:

[0006] An optical lens, comprising six lenses, including the following lenses in order from the object side to the imaging surface along the optical axis:

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

[0008] a second lens having positive refractive power, whose object-side surface is convex and whose image-side surface is concave;

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

[0010] a fourth lens element having positive refractive power, whose object-side surface is concave and whose image-side surface is convex;

[0011] a fifth lens having negative optical power;

[0012] a sixth lens element having positive refractive power, whose object-side surface is convex and whose image-side surface is convex;

[0013] The object-side curvature radius R7 of the fourth lens and the image-side curvature radius R8 of the fourth lens satisfy the following relationship: -0.1<(R7-R8) / (R7+R8)<1.

[0014] 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: -0.6 < (R1 + R2) / (R1 - R2) < 0.9.

[0015] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.3 < TTL / f < 2.7; 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: 1.5 < TTL / IH < 2.3.

[0016] Further preferably, 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: 1.7 < IH / EPD < 3.2; 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: 1.1 < IH / f < 1.8.

[0017] Further preferably, the clear aperture semi-diameter 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: 0.77 < d1 / (IH / 2) / tan(FOV / 2) < 1.81; the optical lens further includes an aperture, the aperture is located between the third lens and the fourth lens or between the second lens and the third lens, and the combined focal length f_back of the lenses behind the aperture and the effective focal length f of the optical lens satisfy: 0.7 < f_back / f < 2.

[0018] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.4 < f1 / f < -0.8; the radius of curvature R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -9 < R1 / f < -1.1; the radius of curvature R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: 0.6 < R2 / f < 5.9.

[0019] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.8 < f2 / f < 11; the radius of curvature R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: 1.2 < R3 / f < 2.5; the radius of curvature R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: 2.1 < R4 / f < 10.

[0020] More preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.7 < f3 / f < 2.2; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.4 < f5 / f < -0.6.

[0021] More preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.8 < f4 / f < 25; the object-side curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: -15 < R7 / f < -1; the image-side curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -2.6 < R8 / f < -0.4.

[0022] More preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.6 < f6 / f < 10; the object-side curvature radius R11 of the sixth lens and the effective focal length f of the optical lens satisfy: 0.5 < R11 / f < 12.4; the image-side curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: -10.5 < R12 / f < -0.6.

[0023] More preferably, the object-side curvature radius R3 of the second lens and the image-side curvature radius R4 of the second lens satisfy: -0.8 < (R3 - R4) / (R3 + R4) < -0.1; the object-side curvature radius R11 of the sixth lens and the image-side curvature radius R12 of the sixth lens satisfy: -0.2 < (R11 + R12) / (R11 - R12) < 0.8.

[0024] The optical lens provided by the present invention uses six 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 aberration, improve the imaging quality of the optical lens, and enable the lens to have one or more advantages such as miniaturization, large target surface, large aperture, large viewing angle, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0028] Figure 3This is the MTF curve of the optical lens in Example 1 of the present invention.

[0029] Figure 4 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0030] Figure 5 FIG. 4 is a graph showing the F-Tan (Theta) distortion curve of the optical lens in Example 2 of the present invention.

[0031] Figure 6 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0032] Figure 7 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0033] Figure 8 Graph showing the F-Tan (Theta) distortion of the optical lens in Example 3 of the present invention.

[0034] Figure 9 This is the MTF curve of the optical lens in Example 3 of the present invention.

[0035] Figure 10 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

[0036] Figure 11 Graph showing the F-Tan (Theta) distortion of the optical lens in Example 4 of the present invention.

[0037] Figure 12 This is the MTF curve of the optical lens in Example 4 of the present invention.

[0038] Figure 13 Schematic diagram of the structure of the optical lens in Example 5 of the present invention.

[0039] Figure 14 FIG. 5 is a graph showing the F-Tan (Theta) distortion curve of the optical lens in Example 5 of the present invention.

[0040] Figure 15 This is the MTF curve of the optical lens in Example 5 of the present invention.

[0041] Figure 16 Schematic diagram of the structure of the optical lens in Example 6 of the present invention.

[0042] Figure 17 FIG. 4 is a graph showing the F-Tan (Theta) distortion curve of the optical lens in Example 6 of the present invention.

[0043] Figure 18 This is the MTF curve of the optical lens in Example 6 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 six lenses in total, 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, and a sixth 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 concave. The third lens may have positive optical power, with its object-side surface being 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 concave and its image-side surface being convex. The fifth lens may have negative optical power, with its object-side surface being concave or convex and its image-side surface being either concave or convex. The sixth lens may have positive optical power, with its object-side surface being convex and its image-side surface being convex.

[0054] In some embodiments, the optical lens may further include an aperture, which may be located between the third and fourth lenses or between the second and third lenses. It will be appreciated that the aperture is used to limit the amount of light entering, thereby varying the brightness of the resulting image. When the aperture is located between the third and fourth lenses or between the second and third lenses, it facilitates correction of aperture aberrations.

[0055] In some embodiments, the optical lens may further include a filter disposed between the sixth 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 object-side curvature radius R7 of the fourth lens element and the image-side curvature radius R8 of the fourth lens element satisfy the following relationship: -0.1 < (R7-R8) / (R7+R8) < 1. Meeting the above range and controlling the fourth lens element to have a suitable surface shape can help improve the correction of higher-order aberrations and reduce the relative illumination attenuation of the optical lens. Furthermore, the fourth lens element adopts a meniscus shape, which helps correct the distortion of the optical lens and improve the imaging quality of the optical lens. More specifically, -0.03 < (R7-R8) / (R7+R8) < 0.93.

[0057] 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: -0.6 < (R1 + R2) / (R1 - R2) < 0.9. By satisfying the above range, the collected light can enter the rear optical system in a divergent form as much as possible, and at the same time, the angle between the light incident on the object side surface of the first lens at the edge field of view can be effectively reduced, and the relative illumination at the edge of the overall lens can be improved. More specifically, -0.56 < (R1 + R2) / (R1 - R2) < 0.86.

[0058] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.3 < TTL / f < 2.7. By satisfying the above range, the length of the lens can be effectively limited, which is beneficial to the miniaturization of the optical lens. More specifically, 2.51 < TTL / f < 2.68.

[0059] In some embodiments, the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 1.5 < TTL / IH < 2.3. By satisfying the above range, when the overall length of the lens is the same, a larger image plane can be ensured, which can match a larger-sized imaging chip to achieve high-definition imaging, and can better achieve the balance between the small overall length and the large image plane of the lens. More specifically, 1.59 < TTL / IH < 2.25.

[0060] 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: 1.7 < IH / EPD < 3.2. By satisfying the above range, it is beneficial to increase the light passing amount, making the brightness of the peripheral field of view and the central field of view more uniform. More specifically, 1.79 < IH / EPD < 2.97.

[0061] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.1 < IH / f < 1.8. By satisfying the above range, controlling the image height and focal length of the optical lens within a reasonable range helps the optical lens to have the characteristic of a large image plane and improve the imaging quality. More specifically, 1.12 < IH / f < 1.66.

[0062] In some embodiments, the half-aperture d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.77 < d1 / (IH / 2) / tan(FOV / 2) < 1.81. By satisfying the above range, a small front aperture can be achieved while meeting the requirements of the optical lens having a large field of view angle and a large image plane.

[0063] In some embodiments, the combined focal length \(f_{rear}\) of the lenses located behind the aperture and the effective focal length \(f\) of the optical lens satisfy: \(0.7 < f_{rear} / f < 2\). Meeting the above range, by reasonably setting the focal lengths of the lens groups before and after the aperture, it is beneficial to balance various aberrations of the system and improve the overall imaging quality. More specifically, \(0.7 < f_{rear} / f < 1.93\).

[0064] In some embodiments, the effective focal length \(f\) of the optical lens and the focal length \(f_1\) of the first lens satisfy: \(-2.4 < f_1 / f < -0.8\); the object-side curvature radius \(R_1\) of the first lens and the effective focal length \(f\) of the optical lens satisfy: \(-9 < R_1 / f < -1.1\); the image-side curvature radius \(R_2\) of the first lens and the effective focal length \(f\) of the optical lens satisfy: \(0.6 < R_2 / f < 5.9\). Meeting the above range, by setting the first lens to have a negative refractive power and a suitable surface shape, it is beneficial for the first lens to accommodate a larger angle of light and collect as much light as possible into the rear optical system, achieving a large field of view while increasing the light flux. More specifically, \(-2.29 < f_1 / f < -0.91\); \(-8.62 < R_1 / f < -1.24\); \(0.66 < R_2 / f < 5.41\).

[0065] In some embodiments, the effective focal length \(f\) of the optical lens and the focal length \(f_2\) of the second lens satisfy: \(1.8 < f_2 / f < 11\); the object-side curvature radius \(R_3\) of the second lens and the effective focal length \(f\) of the optical lens satisfy: \(1.2 < R_3 / f < 2.5\); the image-side curvature radius \(R_4\) of the second lens and the effective focal length \(f\) of the optical lens satisfy: \(2.1 < R_4 / f < 10\); the object-side curvature radius \(R_3\) of the second lens and the image-side curvature radius \(R_4\) of the second lens satisfy: \(-0.8 < (R_3 - R_4) / (R_3 + R_4) < -0.1\). Meeting the above range, by defining the second lens to have an appropriate positive optical power and a suitable surface shape, it has the effect of converging light, enabling the diverging light to smoothly enter the rear optical system, depressing the height of the peripheral light, and being beneficial for reducing the aperture of the rear lens. More specifically, \(1.97 < f_2 / f < 10.24\); \(1.3 < R_3 / f < 2.37\); \(2.29 < R_4 / f < 9.03\); \(-0.76 < (R_3 - R_4) / (R_3 + R_4) < -0.14\).

[0066] In some embodiments, the effective focal length \(f\) of the optical lens and the focal length \(f_3\) of the third lens satisfy: \(0.7 < f_3 / f < 2.2\). Meeting the above range, by defining the third lens to have an appropriate positive optical power, it is beneficial for the convergence of light, can effectively correct the distortion of the edge field of view, reduce the degree of deformation of the edge of the captured image, and improve the image quality. More specifically, \(0.77 < f_3 / f < 2.06\).

[0067] 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 < -0.6. Satisfying the above range makes the light rays in the peripheral field of view show an upward trend, which is conducive to the image points on the imaging surface moving away from the optical axis, so as to facilitate achieving the effect of matching with a large chip, obtaining a larger picture, effectively eliminating aberration, and improving the resolution ability of the optical lens. More specifically, -1.24 < f5 / f < -0.69.

[0068] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.8 < f4 / f < 25; the radius of curvature R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -15 < R7 / f < -1; the radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -2.6 < R8 / f < -0.4. Satisfying the above range is conducive to the convergence of light rays, sharing the positive optical power of the second lens and the third lens, avoiding excessive light ray deflection, and better achieving high-quality imaging of the lens. More specifically, 0.81 < f4 / f < 23.27; -14.65 < R7 / f < -1.09; -2.39 < R8 / f < -0.45.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.6 < f6 / f < 10; the radius of curvature R11 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 0.5 < R11 / f < 12.4; the radius of curvature R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -10.5 < R12 / f < -0.6; the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: -0.2 < (R11 + R12) / (R11 - R12) < 0.8. Satisfying the above range defines that the sixth lens has positive optical power and a suitable surface shape, which is conducive to light ray convergence, making the light ray trend smoothly transition to the rear, reducing the height of the light rays incident on the rear, slowing down the upward trend of the light rays, avoiding the light energy loss caused by the excessive main light ray angle between the large field of view light rays and the chip when reaching the imaging surface, facilitating improving the illuminance of the peripheral field of view, and being conducive to achieving a short optical total length. More specifically, 0.67 < f6 / f < 9.08; 0.56 < R11 / f < 11.33; -9.88 < R12 / f < -0.65; -0.15 < (R11 + R12) / (R11 - R12) < 0.75.

[0070] In some embodiments, the effective focal length f of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.79 < (IH / 2) / (f × Tan(FOV / 2)) < 1.13. Satisfying the above range controls the distortion of the optical lens within a reasonable range.

[0071] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 35° < FOV / Fno < 42°. Meeting the above range defines that the optical lens has an appropriate field of view and aperture value, can collect light at large angles, and obtain good imaging quality. More specifically, 37.7° < FOV / Fno < 40.34°.

[0072] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.18 < BFL / f < 0.92. Meeting the above range defines that the optical lens has an appropriate back focal length, facilitating the reasonable arrangement of the positions of each lens and reducing the processing and assembly difficulty.

[0073] In some embodiments, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis satisfy: 0.51 < ∑CT / TTL < 0.72. Meeting the above range and reasonably configuring the total optical length of the optical lens and the sum of the thicknesses of each lens contribute to achieving high pixel characteristics and improving the imaging quality of the optical lens.

[0074] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis and the effective focal length f of the optical lens satisfy: 1.37 < ΣCT / f < 1.79. Meeting the above range can effectively correct the field curvature and distortion of the optical lens and improve the imaging quality of the optical lens.

[0075] In some embodiments, the optical lens satisfies the following conditional expressions: 4 mm < f < 5.5 mm; 2.3 mm < EPD < 3.2 mm; 11 mm < TTL < 13 mm; 1.5 < Fno < 2; 16° < CRA < 34°; 0.9 mm < BFL < 4 mm; 60° < FOV < 80°; 5.5 mm < IH < 7.5 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 target surface, large aperture, and large field angle. More specifically, 4.3 mm < f < 5.08 mm; 2.32 mm < EPD < 3.18 mm; 11.49 mm < TTL < 12.81 mm; 1.59 < Fno < 1.91; 16.13° < CRA < 33.17°; 0.97 mm < BFL < 3.94 mm; 61° < FOV < 77°; 5.71 mm < IH < 7.39 mm.

[0076] In some embodiments, the lens material of 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. 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. In the optical lens provided by the present invention, the first lens uses a glass lens, the fourth lens, the fifth lens, and the sixth lens use plastic lenses; the second lens and the third lens use glass or plastic 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.

[0077] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens can use 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 first lens of the present invention uses a spherical lens; the fourth lens, the fifth lens, and the sixth lens use aspherical lenses; the second lens and the third lens use spherical or aspherical lenses.

[0078] In various embodiments of the present invention, when the lens uses an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations:

[0079] ;

[0080] 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.

[0081] 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.

[0082] Example 1

[0083] 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, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a filter G1.

[0084] The first lens L1 has negative refractive power, its object-side surface S1 is concave, and its image-side surface S2 is concave;

[0085] The second lens L2 has positive refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave;

[0086] The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is convex;

[0087] The fourth lens L4 has positive refractive power, its object-side surface S7 is concave, and its image-side surface S8 is convex;

[0088] The fifth lens L5 has negative refractive power, its object-side surface S9 is concave, and its image-side surface S10 is convex;

[0089] The sixth lens L6 has positive refractive power, its object-side surface S11 is convex, and its image-side surface S12 is convex;

[0090] The object-side surface S13 and the image-side surface S14 of the filter G1 are both flat surfaces;

[0091] The imaging surface S15 is a plane.

[0092] The first lens L1 and the third lens L3 are glass spherical lenses, and the second lens L2, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are plastic aspherical lenses.

[0093] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0094] Table 1-1

[0095]

[0096] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0097] Table 1-2

[0098]

[0099] In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 100 are respectively as follows: Figure 2 、 Figure 3 shown.

[0100] Figure 2 The F-Tan (Theta) distortion curve for Example 1 shows the distortion of light of different wavelengths at different image heights on the imaging plane. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field of view angle (unit: °). As can be seen from the figure, the distortion of the optical lens is controlled within 0-13%, indicating that the optical lens 100 is capable of excellent distortion correction.

[0101] Figure 3 The MTF (Modulation Transfer Function) curve for Example 1 is shown. It represents the degree of lens imaging 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 0.4 across the entire field of view. Within the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edges of the field of view, demonstrating excellent imaging quality and detail resolution at both low and high frequencies.

[0102] Example 2

[0103] See also Figure 4 , shown is a schematic structural diagram of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[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 F-Tan (Theta) distortion curve and the MTF curve of the optical lens 200 are respectively as follows: Figure 5 、 Figure 6 shown.

[0111] from Figure 5 It can be seen that the distortion of the optical lens is controlled within 0~13%, indicating that the optical lens 200 can correct the distortion well.

[0112] from Figure 6 As can be seen, the MTF value of this embodiment is above 0.48 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies.

[0113] Example 3

[0114] See also Figure 7 , 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 object-side surface S9 of the fifth lens L5 is convex; the image-side surface S10 of the fifth lens L5 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0115] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0116] Table 3-1

[0117]

[0118] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0119] Table 3-2

[0120]

[0121] In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 300 are respectively as follows: Figure 8 、 Figure 9 shown.

[0122] from Figure 8It can be seen that the distortion of the optical lens is controlled within -8%~0, indicating that the optical lens 300 can correct the distortion well.

[0123] from Figure 9 As can be seen, the MTF value of this embodiment is above 0.5 throughout the entire field of view. In the range of 0 to 120 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.

[0124] Example 4

[0125] See also Figure 10 , shown is a schematic structural diagram of an optical lens 400 provided in Example 4 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image-side surface S6 of the third lens L3 is concave; the object-side surface S9 of the fifth lens L5 is convex; the image-side surface S10 of the fifth lens L5 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0126] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0127] Table 4-1

[0128]

[0129] The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0130] Table 4-2

[0131]

[0132] In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 400 are respectively as follows: Figure 11 、 Figure 12 shown.

[0133] from Figure 11 It can be seen that the distortion of the optical lens is controlled within -8%~0, indicating that the optical lens 400 can correct the distortion well.

[0134] from Figure 12 As can be seen, the MTF value of this embodiment is above 0.48 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies.

[0135] Example 5

[0136] See also Figure 13 , shown is a schematic structural diagram of an optical lens 500 provided in Example 5 of the present invention. Compared with Example 1, this embodiment has the following main differences: the aperture ST is provided between the second lens L2 and the third lens L3; the second lens L2 is a glass spherical lens; the third lens L3 is a plastic aspherical lens; the object-side surface S9 of the fifth lens L5 is a convex surface; the image-side surface S10 of the fifth lens L5 is a concave surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0137] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0138] Table 5-1

[0139]

[0140] The surface parameters of the aspheric lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0141] Table 5-2

[0142]

[0143] In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 500 are respectively as follows: Figure 14 、 Figure 15 shown.

[0144] from Figure 14 It can be seen that the distortion of the optical lens is controlled within -8%~0, indicating that the optical lens 500 can correct the distortion well.

[0145] from Figure 15 As can be seen, the MTF value of this embodiment is above 0.38 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies.

[0146] Example 6

[0147] See also Figure 16 , shown is a schematic structural diagram of an optical lens 600 provided in Example 6 of the present invention. Compared with Example 1, this embodiment has the following main differences: the aperture ST is provided between the second lens L2 and the third lens L3; the image-side surface S10 of the fifth lens L5 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0148] The relevant parameters of each lens in the optical lens 600 in Example 6 are shown in Table 6-1.

[0149] Table 6-1

[0150]

[0151] The surface parameters of the aspheric lens of the optical lens 600 in Example 6 are shown in Table 6-2.

[0152] Table 6-2

[0153]

[0154] In this embodiment, the F-Tan (Theta) distortion curve and the MTF curve of the optical lens 600 are respectively as follows: Figure 17 、 Figure 18 shown.

[0155] from Figure 17 It can be seen that the distortion of the optical lens is controlled within -21%~0, indicating that the optical lens 600 can correct the distortion well.

[0156] from Figure 18 As can be seen, the MTF value of this embodiment is above 0.38 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies.

[0157] Please refer to Table 7, 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, chief ray incidence angle CRA at the maximum image height, maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0158] Table 7

[0159]

[0160] In summary, the optical lens provided by the present invention uses six 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, large target area, large aperture, large field of view, and high imaging quality.

[0161] 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.

[0162] 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 six lenses, characterized in that: It sequentially includes, from the object side to the imaging surface along the optical axis: A first lens with negative optical power, whose object side is concave and whose image side is concave; A second lens with positive optical power, whose object side is convex and whose image side is concave; A third lens with positive optical power, whose object side is convex; A fourth lens with positive optical power, whose object side is concave and whose image side is convex; A fifth lens with negative optical power; A sixth lens with positive optical power, whose object side is convex and whose image side is convex; Wherein, the curvature radius R7 of the object side of the fourth lens and the curvature radius R8 of the image side of the fourth lens satisfy: -0.1 < (R7 - R8) / (R7 + R8) < 1; The curvature radius R1 of the object side of the first lens and the curvature radius R2 of the image side of the first lens satisfy: -0.6 < (R1 + R2) / (R1 - R2) < 0.9; The optical lens further includes an aperture stop, the aperture stop is located between the third lens and the fourth lens or between the second lens and the third lens, and the combined focal length f behind of the lenses behind the aperture stop and the effective focal length f of the optical lens satisfy: 0.7 < f behind / f < 2.

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: 2.3 < TTL / f < 2.7; 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: 1.5 < TTL / IH < 2.

3.

3. 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 entrance pupil diameter EPD of the optical lens satisfy: 1.7 < IH / EPD < 3.2; 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: 1.1 < IH / f < 1.

8.

4. The optical lens according to claim 1, wherein: The clear aperture semi-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: 0.77 < d1 / (IH / 2) / tan(FOV / 2) < 1.81; The curvature radius R7 of the object side of the fourth lens and the curvature radius R8 of the image side of the fourth lens satisfy: -0.03 < (R7 - R8) / (R7 + R8) < 0.93; The curvature radius R1 of the object side of the first lens and the curvature radius R2 of the image side of the first lens satisfy: -0.56 < (R + R2) / (R1 - R2) < 0.86; The combined focal length f behind of the lenses behind the aperture stop and the effective focal length f of the optical lens satisfy: 0.7 < f behind / f < 1.

93.

5. 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: -2.4 < f1 / f < -0.8; the curvature radius R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: -9 < R / f < -1.1; the curvature radius R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: 0.6 < R2 / f < 5.

9.

6. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.8 < f2 / f < 11; the curvature radius R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: 1.2 < R3 / f < 2.5; the curvature radius R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: 2.1 < R4 / f < 10.

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: 0.7 < f3 / f < 2.2; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.4 < f5 / f < -0.

6.

8. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.8 < f4 / f < 25; the curvature radius R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -15 < R7 / f < -1; the curvature radius R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -2.6 < R8 / f < -0.

4.

9. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.6 < f6 / f < 10; the curvature radius R11 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 0.5 < R11 / f < 12.4; the curvature radius R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -10.5 < R12 / f < -0.

6.

10. The optical lens according to claim 1, wherein: The curvature radius R3 of the object side surface of the second lens and the curvature radius R4 of the image side surface of the second lens satisfy: -0.8 < (R3 - R4) / (R3 + R4) < -0.1; the curvature radius R11 of the object side surface of the sixth lens and the curvature radius R12 of the image side surface of the sixth lens satisfy: - (R11 + R12) / (R11 - R12) < 0.8.

Images