Optical lens

Abstract

The invention provides an optical lens, which comprises six lenses which sequentially comprise a first lens with negative focal power, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with negative focal power from an object side to an imaging surface, the image side surface of the second lens is a concave surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a convex surface; the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a concave surface; the sixth lens has positive focal power; wherein the curvature radius R7 of the object side surface of the fourth lens and the curvature radius R8 of the image side surface of the fourth lens meet the following conditions: 1.2 lt; (R7 + R8) / (R7-R8) lt; 1.34, 1.34. The optical lens provided by the invention has one or more advantages of large target surface, large aperture, small distortion and the like.

Description

Technical Field

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

[0002] At present, with the booming development of automotive assisted driving and autonomous driving technologies, in-vehicle cameras play a crucial role. There are various types of in-vehicle cameras, including interior view, rear view, front view, side view, surround view, etc. They each have unique functions and different application scenarios. For example, the main function of the front-view wide-angle camera is to accurately identify nearby objects, and in scenarios such as urban road conditions and low-speed vehicle driving, it can provide key information for driving.

[0003] The front-view camera is a core component of the ADAS (Advanced Driver Assistance System). It not only shoulders the heavy responsibility of ranging, but also can accurately identify objects and clearly distinguish road markings. Therefore, the visual algorithms required for it are extremely complex and the technical threshold is quite high. In order to give full play to the performance of the front-view camera, it has become an urgent task to develop an optical lens with excellent imaging effects. Only in this way can it be ensured that it works stably and efficiently in complex driving environments and lay a solid foundation for the further development of autonomous driving technologies. Summary of the Invention

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

[0005] The technical solution adopted by the present invention is as follows:

[0006] An optical lens, which has a total of six lenses, and successively includes from the object side to the imaging surface along the optical axis:

[0007] A first lens with negative optical power, whose object side is concave and whose image side is convex;

[0008] A second lens with negative optical power, whose image side is concave;

[0009] A third lens with positive optical power, whose object side is convex and whose image side is convex;

[0010] A fourth lens with positive optical power, whose object side is concave and whose image side is convex;

[0011] A fifth lens with negative optical power, whose object side is concave and whose image side is concave;

[0012] A sixth lens with positive optical power;

[0013] Wherein, the radius of curvature R7 of the object side of the fourth lens and the radius of curvature R8 of the image side of the fourth lens satisfy: 1.2 < (R7 + R8) / (R7 - R8) < 1.34.

[0014] More preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.2 < TTL / f < 5.6; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 4.9 < TTL / IH < 5.1.

[0015] More preferably, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 39° < FOV / Fno < 41°; 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 < 1.8.

[0016] More preferably, the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1 < IH / f < 1.15; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.65 < BFL / f < 0.95.

[0017] More 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 of view angle of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 2.3 < d1 / (IH / 2) / tan(FOV / 2) < 3.2; the combined focal length f12 of the first lens and the second lens and the combined focal length f3456 of the third lens, the fourth lens, the fifth lens and the sixth lens satisfy: -1.8 < f12 / f3456 < -1.1.

[0018] More preferably, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -14 < f1 / f < -7.4; the curvature radius R1 of the object side surface of the first lens and the curvature radius R2 of the image side surface of the first lens satisfy: -0.36 < (R1 - R2) / (R1 + R2) < -0.27.

[0019] More preferably, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1 < f3 / f < 1.4; 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: -1093 < (R5 - R6) / (R5 + R6) < -17.

[0020] Further preferably, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1 < f4 / f < 1.4; the object-side curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: -9.7 < R7 / f < -7.1; the image-side curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -1.2 < R8 / f < -0.9.

[0021] Further preferably, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -0.64 < f5 / f < -0.55; the object-side curvature radius R9 of the fifth lens and the image-side curvature radius R10 of the fifth lens satisfy: |(R9 + R10) / (R9 - R10)| < 0.14.

[0022] Further preferably, the sagittal height Sag7 of the object-side clear aperture of the fourth lens and the object-side clear aperture diameter d7 of the fourth lens satisfy: -0.06 < Sag7 / d7 < -0.03; the sagittal height Sag8 of the image-side clear aperture of the fourth lens and the image-side clear aperture diameter d8 of the fourth lens satisfy: -0.43 < Sag8 / d8 < -0.39.

[0023] 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 aberrations, improve the imaging quality of the optical lens, and endow the lens with one or more advantages such as a large target surface, a large aperture, and small distortion. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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, where:

[0025] Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0026] Figure 2 is a field curvature curve graph of the optical lens in Embodiment 1 of the present invention.

[0027] Figure 3 is an F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 4 is an MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 5 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0030] Figure 6It is the field curvature curve graph of the optical lens in Embodiment 2 of the present invention.

[0031] Figure 7 It is the F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 8 It is the MTF curve graph of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 9 It is the structural schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0034] Figure 10 It is the field curvature curve graph of the optical lens in Embodiment 3 of the present invention.

[0035] Figure 11 It is the F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 3 of the present invention.

[0036] Figure 12 It is the MTF curve graph of the optical lens in Embodiment 3 of the present invention.

[0037] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0038] To better understand the present application, more detailed descriptions will be made on various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application and do not 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.

[0039] It should be noted that in this specification, the expressions such as first, second, third, etc. are only used to distinguish one feature from another feature and do not represent any limitation on the feature. Therefore, without departing from the teachings of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0040] In the drawings, for the sake of convenience of illustration, the thickness, size and shape of the lens have been slightly exaggerated. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the spherical or aspherical surfaces shown in the drawings. The drawings are only for illustration and are not drawn strictly to scale.

[0041] In this text, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object being photographed is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0042] It should also be understood that the terms "comprising", "comprising of", "having", "containing" and / or "containing of", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when an expression such as "at least one of..." appears after a list of listed features, it modifies the entire list of listed features, rather than an individual element in the list. In addition, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0043] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0044] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments may be combined with each other. The following will refer to the drawings and combine with embodiments to detail the present application.

[0045] The optical lens provided by the embodiment of the present invention includes six lenses, which are, 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.

[0046] In some embodiments, the first lens may have a negative optical power, its object side surface may be concave, and its image side surface may be convex. The second lens may have a negative optical power, its object side surface may be convex or concave, and its image side surface may be concave. The third lens may have a positive optical power, its object side surface may be convex, and its image side surface may be convex. The fourth lens may have a positive optical power, its object side surface may be concave, and its image side surface may be convex. The fifth lens may have a negative optical power, its object side surface may be concave, and its image side surface may be concave. The sixth lens may have a positive optical power, its object side surface may be convex or concave near the optical axis, and its image side surface may be concave or convex near the optical axis.

[0047] In some embodiments, the optical lens may further include a diaphragm, which may be located between the second lens and the third lens. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the image. When the diaphragm is located between the second lens and the third lens, it is convenient for the correction of diaphragm aberration.

[0048] In some embodiments, the optical lens may further include a filter and a protective glass, which are sequentially arranged along the optical axis 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. The protective glass plays a role in protecting the optical lens, preventing the photosensitive chip from being damaged, and can improve the shock resistance and scratch resistance of the optical lens, while having little impact on the imaging quality of the optical lens.

[0049] In some embodiments, the fourth lens and the fifth lens may be glued together to form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0050] In some embodiments, the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 1.2 < (R7 + R8) / (R7 - R8) < 1.34. Meeting the above range and controlling the fourth lens to have an appropriate surface shape can effectively correct the aberration of the optical lens and improve the imaging quality.

[0051] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.2 < TTL / f < 5.6; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 4.9 < TTL / IH < 5.1. Meeting the above range is beneficial to achieving the balance of the small volume and large image surface of the optical lens, making the lens have a smaller total length. More specifically: 5.21 < TTL / f < 5.51; 4.9 < TTL / IH < 5.02.

[0052] In some embodiments, the maximum field of view angle FOV of the optical lens and the f - number Fno of the optical lens satisfy: 39° < FOV / Fno < 41°; 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 < 1.8. Meeting the above range and reasonably limiting the ratio of the field of view angle to the f - number can collect light at large angles and obtain good imaging quality. At the same time, reasonably limiting the ratio of the image height to the entrance pupil diameter is beneficial to increasing the light - passing amount, making the brightness of the peripheral field of view and the central field of view more uniform. More specifically: 39.25° < FOV / Fno < 40.01°.

[0053] 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 < IH / f < 1.15; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.65 < BFL / f < 0.95. Meeting the above ranges and reasonably controlling the ratio of the image height to the focal length of the optical lens helps the optical lens to have a larger image plane. At the same time, defining that the optical lens has an appropriate back focal length facilitates the reasonable arrangement of the positions of the respective lenses and reduces the processing and assembly difficulty. More specifically: 1.05 < IH / f < 1.11; 0.67 < BFL / f < 0.94.

[0054] In some embodiments, the clear aperture radius 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: 2.3 < d1 / (IH / 2) / tan(FOV / 2) < 3.2; the combined focal length f12 of the first lens and the second lens and the combined focal length f3456 of the third lens, the fourth lens, the fifth lens, and the sixth lens satisfy: -1.8 < f12 / f3456 < -1.1. Meeting the above ranges can reasonably arrange the overall geometry of the optical lens and improve its structural stability. At the same time, making the optical power of the front and rear lens groups of the optical lens within an appropriate range can reduce the difficulty of lens aberration correction and improve the imaging quality of the optical lens. More specifically: 2.34 < d1 / (IH / 2) / tan(FOV / 2) < 3.18; -1.77 < f12 / f3456 < -1.11.

[0055] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -14 < f1 / f < -7.4; the curvature radius R1 of the object side surface of the first lens and the curvature radius R2 of the image side surface of the first lens satisfy: -0.36 < (R1 - R2) / (R1 + R2) < -0.27. Meeting the above ranges, by reasonably defining the proportion of the optical power of the first lens and its surface shape, the light passing through it can be diverged, which is beneficial to achieving a small front aperture. More specifically: -13.32 < f1 / f < -7.41.

[0056] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1 < f3 / f < 1.4; the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -1093 < (R5 - R6) / (R5 + R6) < -17. Satisfying the above ranges, by reasonably defining the proportion of the optical power of the third lens and its surface shape, the aberration generated at the front end of the lens can be effectively corrected, and the imaging quality of the lens can be improved. More specifically: 1.07 < f3 / f < 1.32; -1092.07 < (R5 - R6) / (R5 + R6) < -17.95.

[0057] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1 < f4 / f < 1.4; 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: -9.7 < R7 / f < -7.1; 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: -1.2 < R8 / f < -0.9. Satisfying the above ranges, by reasonably defining the proportion of the optical power of the fourth lens and its surface shape, the aberration of the optical lens can be effectively corrected, and the imaging quality can be improved. More specifically: 1.06 < f4 / f < 1.34; -9.68 < R7 / f < -7.14; -1.11 < R8 / f < -0.9.

[0058] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -0.64 < f5 / f < -0.55; the radius of curvature R9 of the object side surface of the fifth lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: |(R9 + R10) / (R9 - R10)| < 0.14. Satisfying the above ranges, by reasonably defining the proportion of the optical power of the fifth lens and its surface shape, the spherical aberration can be optimized, and high-quality imaging can be achieved. More specifically: -0.14 < (R9 + R10) / (R9 - R10) < 0.11.

[0059] In some embodiments, the sagittal height Sag7 of the object side clear aperture of the fourth lens and the object side clear aperture d7 of the fourth lens satisfy: -0.06 < Sag7 / d7 < -0.03; the sagittal height Sag8 of the image side clear aperture of the fourth lens and the image side clear aperture d8 of the fourth lens satisfy: -0.43 < Sag8 / d8 < -0.39. Satisfying the above ranges helps to control the light path and highlight the detailed information of the central field of view of the optical lens.

[0060] In some embodiments, the sum ΣCT of the central thicknesses of the first lens to the sixth lens along the optical axis and the overall optical length TTL of the optical lens satisfy: 0.3 < ΣCT / TTL < 0.47. Meeting the above range and controlling the overall optical length of the optical lens and the sum of the central thicknesses of each lens within a reasonable range helps to achieve high pixel characteristics and improve the imaging quality of the optical lens.

[0061] In some embodiments, the sum ΣCT 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: 1.7 < ΣCT / f < 2.5. Meeting the above range and controlling the effective focal length of the optical lens and the sum of the central thicknesses of each lens within a reasonable range can make the lens more compact. More specifically: 1.71 < ΣCT / f < 2.47.

[0062] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -3.2 < f2 / f < -2. Meeting the above range and reasonably limiting the proportion of the optical power of the second lens is beneficial to achieving a larger light input amount and increasing the relative illumination. More specifically: -3.15 < f2 / f < -2.05.

[0063] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.5 < f6 / f < 6.8. Meeting the above range and reasonably limiting the proportion of the optical power of the sixth lens is beneficial to light convergence, enabling the light trend to smoothly transition to the rear, reducing the height of the light incident on the rear, slowing down the upward trend of the light, and being beneficial to improving the illumination of the edge field of view. More specifically: 1.55 < f6 / f < 6.73.

[0064] In some embodiments, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: -2.6 < f12 / f < -1.5. Meeting the above range and making the proportion of the optical power of the front lens group of the optical lens within a suitable range can diverge light, helping to obtain a large field of view angle and thus expanding the imaging range. More specifically: -2.51 < f12 / f < -1.56.

[0065] In some embodiments, the combined focal length f3456 of the third lens, the fourth lens, the fifth lens, and the sixth lens and the effective focal length f of the optical lens satisfy: 1.2 < f3456 / f < 1.5. Meeting the above range and making the proportion of the optical power of the rear lens group of the optical lens within a suitable range can converge light, reduce the difficulty of lens aberration correction, and improve the imaging quality of the optical lens. More specifically: 1.28 < f3456 / f < 1.43.

[0066] In some embodiments, 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: -4.1 < R1 / f < -2.4; 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: -8.2 < R2 / f < -4.3. Meeting the above ranges can control the first lens to have an appropriate surface shape, which can diverge the light passing through it, facilitating the achievement of a small front aperture. More specifically: -4.06 < R1 / f < -2.44; -8.12 < R2 / f < -4.3.

[0067] In some embodiments, the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R2 of the image side surface of the first lens satisfy: 0.48 < R1 / R2 < 0.58. Meeting the above ranges can control the first lens to have an appropriate surface shape, which can diverge the light passing through it, facilitating the achievement of a small front aperture.

[0068] In some embodiments, the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 7 < R7 / R8 < 10.6. Meeting the above ranges can control the fourth lens to have an appropriate surface shape, which can effectively correct the aberration of the optical lens and improve the imaging quality. More specifically: 7.06 < R7 / R8 < 10.58.

[0069] In some embodiments, the optical lens satisfies the following conditional expressions: 6.8 mm < f < 7.3 mm; 63° < FOV < 65°; 4.2 mm < EPD < 4.5 mm; 37 mm < TTL < 39 mm; 1.55 < Fno < 1.65; 7.5 mm < IH < 7.8 mm; 12° < CRA < 18°; 4.8 mm < BFL < 6.8 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the principal ray incident angle at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. Meeting the above ranges, the optical lens has at least one or more advantages such as a large target surface, a large aperture, and low distortion. More specifically: 6.89 mm < f < 7.24 mm; 63.9° < FOV < 64.1°; 4.22 mm < EPD < 4.45 mm; 37.79 mm < TTL < 38.01 mm; 1.59 < Fno < 1.64; 7.55 mm < IH < 7.71 mm; 12.99° < CRA < 17.02°; 4.83 mm < BFL < 6.73 mm.

[0070] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The optical lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0071] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the third lens and the sixth lens of the present invention adopt aspherical lenses, and the first lens, the second lens, the fourth lens, and the fifth lens adopt spherical lenses.

[0072] In various embodiments of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0073]

[0074] Where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the conic coefficient, and B, C, D, E, and F are the coefficients of the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order curved surfaces respectively.

[0075] The present invention will be further described in multiple embodiments below. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are slightly different. For specific differences, please refer to the parameter tables of each embodiment. The following embodiments are only the preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any other changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0076] Embodiment 1

[0077] Please refer to Figure 1 , which shows a schematic structural diagram of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 sequentially includes, along the optical axis from the object side to the imaging surface: a first lens L1, a second lens L2, a diaphragm ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a filter G1, and a protective glass G2.

[0078] Among them, the first lens L1 has a negative optical power. Its object side surface S1 is concave, and its image side surface S2 is convex;

[0079] The second lens L2 has a negative optical power, its object side S3 is convex, and its image side S4 is concave;

[0080] The third lens L3 has a positive optical power, its object side S5 is convex, and its image side S6 is convex;

[0081] The fourth lens L4 has a positive optical power, its object side S7 is concave, and its image side S8 is convex;

[0082] The fifth lens L5 has a negative optical power, its object side S8 is concave, and its image side S9 is concave;

[0083] The fourth lens L4 and the fifth lens L5 form a cemented lens group, that is, the cemented surface of the image side of the fourth lens L4 and the object side of the fifth lens L5 is S8;

[0084] The sixth lens L6 has a positive optical power, its object side S10 is convex, and its image side S11 is concave;

[0085] The object side S12 and the image side S13 of the filter G1 are both flat;

[0086] The object side S14 and the image side S15 of the protective glass G2 are both flat;

[0087] The imaging surface S16 is flat.

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

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

[0090] Table 1-1

[0091]

[0092]

[0093] The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0094] Table 1-2

[0095] Face number K B C D E F S5 -2.14E-01 -1.07E-04 -9.07E-07 -3.32E-08 1.03E-09 -1.99E-11 S6 -6.04E+00 -1.41E-04 4.46E-06 -1.30E-07 2.37E-09 -2.66E-11 S10 3.68E-01 1.58E-04 -3.23E-05 -1.68E-06 9.02E-08 -4.22E-09 S11 2.86E+01 6.22E-04 -2.22E-05 2.45E-07 -1.14E-07 1.30E-09

[0096] In this embodiment, the field curvature curve graph, the F-Tan(Theta) distortion curve graph, and the MTF curve graph of the optical lens 100 are respectively as Figure 2 , Figure 3 , Figure 4as shown

[0097] Figure 2 The field curvature curve of Example 1 is shown, which represents the curvature of light rays with different wavelengths in the meridional image plane and the sagittal image plane. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.02 mm, indicating that the optical lens 100 can correct the field curvature well.

[0098] Figure 3 The F-Tan(Theta) distortion curve of Example 1 is shown, which represents the distortion of light rays with different wavelengths at different image heights on the imaging plane. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the distortion of the optical lens is controlled within -15% to 0%, indicating that the optical lens 100 can correct the distortion well.

[0099] Figure 4 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the modulation of the lens imaging at different spatial frequencies in each field of view. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF value of this embodiment is above 0.6 within the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases uniformly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0100] Example 2

[0101] Please refer to Figure 5 , which shows the structural schematic diagram of the optical lens 200 provided in Embodiment 2 of the present invention. Compared with Embodiment 1, the main differences are: the object side surface S3 of the second lens L2 is a concave surface; the image side surface S11 of the sixth lens L6 is a convex surface near the optical axis; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0102] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0103] Table 2-1

[0104]

[0105] The surface type parameters of the aspherical lenses in the optical lens 200 in Example 2 are shown in Table 2-2.

[0106] Table 2-2

[0107] Face number K B C D E F S5 -7.37E-01 -8.80E-05 8.41E-08 -3.03E-08 1.29E-09 -2.47E-11 S6 -5.42E+00 -1.59E-04 4.33E-06 -1.15E-07 2.38E-09 -3.06E-11 S10 1.08E+00 6.24E-04 -4.30E-06 -8.04E-07 5.26E-08 -1.02E-09 S11 1.69E+01 1.37E-03 1.69E-05 1.73E-07 4.25E-08 1.28E-09

[0108] In this embodiment, the field curvature curve graph, F-Tan(Theta) distortion curve graph, and MTF curve graph of the optical lens 200 are respectively as follows Figure 6 , Figure 7 , Figure 8 . It can be seen from Figure 6 that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.03 mm to 0.02 mm, indicating that the optical lens 200 can correct the field curvature well. It can be seen from Figure 7 that the distortion of the optical lens 200 is controlled within -15% to 0%, indicating that the optical lens 200 can correct the distortion well. It can be seen from Figure 8 that the MTF value of this embodiment is above 0.5 within the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve smoothly decreases uniformly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0109] Embodiment 3

[0110] Please refer to Figure 9 , which shows the structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present invention. Compared with Embodiment 1, the main differences are: the object side surface S10 of the sixth lens L6 is concave near the optical axis, and the image side surface S11 is convex near the optical axis; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0111] The relevant parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0112] Table 3-1

[0113]

[0114] The surface type parameters of the aspherical lenses of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0115] Table 3-2

[0116]

[0117]

[0118] In this embodiment, the field curvature curve graph, F-Tan(Theta) distortion curve graph, and MTF curve graph of the optical lens 300 are respectively as follows Figure 10 , Figure 11 , Figure 12 . It can be seen from Figure 10It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.05 mm to 0.02 mm, indicating that the optical lens 300 can correct the field curvature well. From Figure 11 It can be seen that the distortion of the optical lens 300 is controlled within -15% to 0%, indicating that the optical lens 300 can correct the distortion well. From Figure 12 It can be seen that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases uniformly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0119] Please refer to Table 4 for the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the chief ray angle of incidence CRA at the maximum image height, the true image height IH corresponding to the maximum field of view angle, the maximum field of view angle FOV, the entrance pupil diameter EPD, the back focal length BFL, and the values corresponding to each conditional formula in each embodiment.

[0120] Table 4

[0121]

[0122]

[0123] In summary of the above embodiments, 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 aberrations, and improve the imaging quality of the optical lens, enabling the lens to have one or more advantages such as a large target surface, a large aperture, and small distortion.

[0124] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0125] The above embodiments only represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. An optical lens, consisting of six lenses in total, 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 surface is concave and whose image side surface is convex; A second lens with negative optical power, whose image side surface is concave; A third lens with positive optical power, whose object side surface is convex and whose image side surface is convex; A fourth lens with positive optical power, whose object side surface is concave and whose image side surface is convex; A fifth lens with negative optical power, whose object side surface is concave and whose image side surface is concave; A sixth lens with positive optical power; Wherein, the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 1.2 < (R7 + R8) / (R7 - R8) < 1.

34.

2. The optical lens according to claim 1, characterized in that, The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.2 < TTL / f < 5.6; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 4.9 < TTL / IH < 5.

1.

3. The optical lens according to claim 1, wherein The maximum field of view angle FOV of the optical lens and the f-number Fno of the optical lens satisfy: 39° < FOV / Fno < 41°; 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 < 1.

8.

4. The optical lens according to claim 1, characterized in that The true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1 < IH / f < 1.15; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.65 < BFL / f < 0.

95.

5. The optical lens according to claim 1, wherein The clear aperture radius 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: 2.3 < d1 / (IH / 2) / tan(FOV / 2) < 3.2; the combined focal length f12 of the first lens and the second lens and the combined focal length f3456 of the third lens, the fourth lens, the fifth lens and the sixth lens satisfy: -1.8 < f12 / f3456 < -1.

1.

6. The optical lens according to claim 1, wherein The focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -14 < f1 / f < -7.4; 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: -0.36 < (R1 - R2) / (R1 + R2) < -0.

27.

7. The optical lens according to claim 1, wherein The focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1 < f3 / f < 1.4; the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -1093 < (R5 - R6) / (R5 + R6) < -17.

8. The optical lens according to claim 1, wherein The focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1 < f4 / f < 1.4; the object-side curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: -9.7 < R7 / f < -7.1; the image-side curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -1.2 < R8 / f < -0.

9.

9. The optical lens according to claim 1, wherein The focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: -0.64 < f5 / f < -0.55; the object-side curvature radius R9 of the fifth lens and the image-side curvature radius R10 of the fifth lens satisfy: |(R9 + R10) / (R9 - R10)| < 0.

14.

10. The optical lens according to claim 1, characterized in that, The object-side clear aperture sag Sag7 of the fourth lens and the object-side clear aperture d7 of the fourth lens satisfy: -0.06 < Sag7 / d7 < -0.03; the image-side clear aperture sag Sag8 of the fourth lens and the image-side clear aperture d8 of the fourth lens satisfy: -0.43 < Sag8 / d8 < -0.39.

Images