Optical lens

Abstract

The invention provides an optical lens, which comprises six lenses from an object side to an imaging surface along an optical axis: a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with negative focal power and a fifth lens with positive focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a concave surface; the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a concave surface; the sixth lens has negative focal power; 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 meet the formula:-0.9 lt; (R5-R6) / (R5 + R6) lt; and-0.4. According to the optical lens provided by the invention, the six lenses with specific focal power are adopted, and through specific surface shape matching and reasonable focal power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved.

Description

Technical Field

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

[0002] With the continuous improvement of people's requirements for driving experience, in-vehicle application optical lenses are increasingly used in intelligent driving, and the status of in-vehicle optical lenses in the automotive-related industry is constantly rising.

[0003] Advanced Driver Assistance Systems (ADAS) play an important role in intelligent driving. It collects environmental information through various lenses and sensors to ensure the driving safety of the driver. In addition to requiring the optical lens to have a thin, light, short and small shape and high pixel and high resolution characteristics, the existing ADAS system lenses also require the optical lens to be able to clearly image under low illumination conditions. Therefore, it is necessary to develop an optical lens with good imaging effect. Summary of the Invention

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

[0005] The technical solution adopted by the present invention is as follows: An optical lens, comprising a total of six lenses, which in sequence from the object side to the imaging surface along the optical axis include: A first lens with positive optical power, the object side surface of which is convex; A second lens with positive optical power, the object side surface of which is concave and the image side surface of which is convex; A third lens with positive optical power, the object side surface of which is convex and the image side surface of which is concave; A fourth lens with negative optical power, the object side surface of which is convex and the image side surface of which is concave; A fifth lens with positive optical power, the object side surface of which is convex and the image side surface of which is concave; A sixth lens with negative optical power; Wherein, 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: -0.9 < (R5 - R6) / (R5 + R6) < -0.4.

[0006] Further preferably, the maximum field of view FOV of the optical lens and the f-number Fno of the optical lens satisfy: 10.7° < FOV / Fno < 15.5°; the total optical length TTL of the optical lens, the maximum field of view FOV of the optical lens and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 103 < 180°×TTL / IH / FOV < 135.

[0007] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: f2 / f > 20.

[0008] Further preferably, the effective focal length f of the optical lens and the radius of curvature R5 of the object side surface of the third lens satisfy: 0.4 < R5 / f < 0.8; the effective focal length f of the optical lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 2.7 < R6 / f < 3.9.

[0009] Further preferably, the effective focal length f of the optical lens and the radius of curvature R7 of the object side surface of the fourth lens satisfy: 2.7 < R7 / f < 3.9; the effective focal length f of the optical lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 0.3 < R8 / f < 0.6.

[0010] Further preferably, the effective focal length f of the optical lens and the radius of curvature R9 of the object side surface of the fifth lens satisfy: 0.5 < R9 / f < 1; the effective focal length f of the optical lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: 2.7 < R10 / f < 3.9.

[0011] Further preferably, 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: 0.5 < R11 / R12 < 1.3.

[0012] Further preferably, 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: 0.5 < (R7 - R8) / (R7 + R8) < 0.9.

[0013] Further preferably, 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: -0.9 < (R9 - R10) / (R9 + R10) < -0.5.

[0014] Further preferably, the sagitta Sag5 of the object side clear aperture of the third lens and the object side clear aperture diameter d5 of the third lens satisfy: 0.1 < Sag5 / d5 < 0.35; the sagitta Sag6 of the image side clear aperture of the third lens and the image side clear aperture diameter d6 of the third lens satisfy: 0 < Sag6 / d6 < 0.1.

[0015] The optical lens provided by the present invention adopts six lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberration, improve the imaging quality of the optical lens, and enable the lens to have one or more advantages such as long focal length, large target surface, and high imaging quality. Description of the Drawings

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 Schematic diagram of the structure of the optical lens in Example 1 of the present invention.

[0017] Figure 2 It is a field curvature curve diagram of the optical lens in Example 1 of the present invention.

[0018] Figure 3 : is the F-Tan (Theta) distortion curve of the optical lens in Example 1 of the present invention.

[0019] Figure 4 Graph showing the axial aberration of the optical lens in Example 1 of the present invention.

[0020] Figure 5 Graph showing the vertical axis chromatic aberration of the optical lens in Example 1 of the present invention.

[0021] Figure 6 This is the MTF curve diagram of the optical lens in Example 1 of the present invention.

[0022] Figure 7 This is a relative illumination curve diagram of the optical lens in Example 1 of the present invention.

[0023] Figure 8 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0024] Fig. 9 It is a field curvature curve diagram of the optical lens in Example 2 of the present invention.

[0025] Fig.10 : is the F-Tan (Theta) distortion curve of the optical lens in Example 2 of the present invention.

[0026] Fig.11 Graph showing the axial aberration of the optical lens in Embodiment 2 of the present invention.

[0027] Fig.12 Graph showing the vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0028] Fig.13 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0029] Fig.14 This is a relative illumination curve diagram of the optical lens in Example 2 of the present invention.

[0030] Fig.15 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0031] Fig.16 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0032] Fig.17 : is the F-Tan (Theta) distortion curve of the optical lens in Example 3 of the present invention.

[0033] Fig.18 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0034] Fig.19 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0035] Fig. 20 This is the MTF curve diagram of the optical lens in Example 3 of the present invention.

[0036] Fig.21 This is a relative illumination curve diagram of the optical lens in Example 3 of the present invention.

[0037] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0038] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application, and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

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

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

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

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

[0043] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0044] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0045] The optical lens provided by the embodiment of the present invention comprises six lenses, which are a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens in order from the object side to the imaging surface along the optical axis.

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

[0047] In some embodiments, the optical lens may further include an aperture, and the aperture may be located between the second lens and the third lens. It is understood that the aperture is used to limit the amount of light entering to change the brightness of the image. When the aperture is located between the second lens and the third lens, it is convenient to correct the aperture aberration.

[0048] In some embodiments, the optical lens may further include a filter and a protective glass. The filter and the protective glass may be sequentially disposed between the sixth lens and the imaging surface along the optical axis. 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 anti-impact and scratch-resistant capabilities of the optical lens, while having almost no impact on the imaging quality of the optical lens.

[0049] In some embodiments, the third lens and the fourth 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 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: -0.9 < (R5 - R6) / (R5 + R6) < -0.4. Satisfying the above range, by reasonably setting the surface shape of the third lens, it is beneficial to better achieve the convergence of light, enable the converged light to smoothly enter the subsequent optical system, reduce the difficulty of correcting the marginal field distortion, and improve the overall imaging quality. More specifically, -0.73 < (R5 + R6) / (R5 - R6) < 0.67.

[0051] In some embodiments, the maximum field of view FOV of the optical lens and the f-number Fno of the optical lens satisfy: 10.7° < FOV / Fno < 15.5°. Satisfying the above range, it is defined that the optical lens has a suitable field of view and f-number, which can collect light at a large angle and obtain good imaging quality. More specifically, 11.81° < FOV / Fno < 14.01°.

[0052] In some embodiments, the overall optical length TTL of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 103 < 180°×TTL / IH / FOV < 135. Satisfying the above range is beneficial to balance the relationship among the overall length, image height, and field of view of the optical lens. More specifically, 103.97 < 180°×TTL / IH / FOV < 134.22.

[0053] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: f2 / f > 20. Satisfying the above range, it is defined that the second lens has a positive optical power, which is beneficial to further converge the light, make the light trend smoother, optimize the aberration, and improve the resolution. More specifically, 22.86 < f2 / f < 173.75.

[0054] In some embodiments, the effective focal length f of the optical lens and the curvature radius R5 of the object side surface of the third lens satisfy: 0.4 < R5 / f < 0.8; the effective focal length f of the optical lens and the curvature radius R6 of the image side surface of the third lens satisfy: 2.7 < R6 / f < 3.9. Meeting the above ranges, by reasonably setting the surface shape of the third lens, it is beneficial to better achieve the convergence of light, enable the converged light to smoothly enter the rear optical system, reduce the difficulty of correcting the marginal field distortion, and improve the overall imaging quality. More specifically, 3.06 < R5 / f < 3.59; 0.41 < R6 / f < 0.46.

[0055] In some embodiments, the effective focal length f of the optical lens and the curvature radius R7 of the object side surface of the fourth lens satisfy: 2.7 < R7 / f < 3.9; the effective focal length f of the optical lens and the curvature radius R8 of the image side surface of the fourth lens satisfy: 0.3 < R8 / f < 0.6. Meeting the above ranges, by reasonably setting the surface shape of the fourth lens, the aberration generated by the front lens can be balanced, and the imaging quality of the optical lens can be improved. More specifically, 3.06 < R7 / f < 3.59; 0.41 < R8 / f < 0.46.

[0056] In some embodiments, the effective focal length f of the optical lens and the curvature radius R9 of the object side surface of the fifth lens satisfy: 0.5 < R9 / f < 1; the effective focal length f of the optical lens and the curvature radius R10 of the image side surface of the fifth lens satisfy: 2.7 < R10 / f < 3.9. Meeting the above ranges, the surface shapes of the object side and the image side of the fifth lens can be restricted, and it has the characteristic of correcting field curvature, which is beneficial to the correction of the aberration of the entire optical lens. More specifically, 0.56 < R9 / f < 0.91; 3.06 < R10 / f < 3.59.

[0057] In some embodiments, 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: 0.5 < R11 / R12 < 1.3. Meeting the above ranges, controlling the sixth lens to have a suitable surface shape is beneficial to increasing the imaging area and the field of view angle of the optical lens, is beneficial to balancing the aberration of the optical lens, and improves the imaging quality of the optical lens. More specifically, 0.62 < R11 / R12 < 1.2.

[0058] In some embodiments, 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 satisfy: 0.5 < (R7 - R8) / (R7 + R8) < 0.9. Meeting the above ranges, the aberration can be effectively corrected, and the imaging quality of the optical lens can be improved. More specifically, 0.75 < (R7 - R8) / (R7 + R8) < 0.79.

[0059] In some embodiments, the radius of curvature R9 of the object side surface of the fifth lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: -0.9 < (R9 - R10) / (R9 + R10) < -0.5. Meeting the above range can limit the surface shapes of the object side and the image side of the fifth lens, has the characteristic of correcting field curvature, and is beneficial to the correction of the aberration of the entire optical lens. More specifically, -0.7 < (R9 - R10) / (R9 + R10) < -0.59.

[0060] In some embodiments, the sagittal height Sag5 of the clear aperture of the object side surface of the third lens and the clear aperture diameter d5 of the object side surface of the third lens satisfy: 0.1 < Sag5 / d5 < 0.35; the sagittal height Sag6 of the clear aperture of the image side surface of the third lens and the clear aperture diameter d6 of the image side surface of the third lens satisfy: 0 < Sag6 / d6 < 0.1. Meeting the above range helps to control the trend of the light rays in the edge field of view and highlights the detailed information of the central field of view of the optical lens. More specifically, 0.16 < Sag5 / d5 < 0.36; 0.02 < Sag6 / d6 < 0.05.

[0061] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.8 < TTL / f < 2.5. Meeting the above range is beneficial to limiting the overall length of the lens while better realizing the telephoto performance of the system. More specifically, 1.97 < TTL / f < 2.23.

[0062] 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: 3.6 < TTL / IH < 5.3. Meeting the above range can better achieve the balance between the overall length of the lens and the image plane. More specifically, 4.03 < TTL / IH < 4.86.

[0063] 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: 0.9 < IH / EPD < 1.2. Meeting the above range can increase the width of the light beam entering the optical lens, improve the brightness at the image plane of the optical lens, and avoid the generation of vignetting. More specifically, 0.97 < IH / EPD < 1.08.

[0064] 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: 0.4 < IH / f < 0.6. Meeting the above range controls the image height and focal length of the optical lens within a reasonable range, helps the optical lens to have the characteristics of a long focal length and a large image plane, and improves the imaging quality. More specifically, 0.45 < IH / f < 0.5.

[0065] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.25 < BFL / f < 0.45. Meeting the above range defines that the optical lens has an appropriate back focus, facilitating the reasonable arrangement of the positions of each lens and reducing the processing and assembly difficulty. More specifically, 0.27 < BFL / f < 0.34.

[0066] In some embodiments, the overall optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis satisfy: 0.6 < ∑CT / TTL < 0.9. Meeting the above range and reasonably configuring the overall optical length of the optical lens and the sum of the thicknesses of each lens helps to achieve high-pixel characteristics and improve the imaging quality of the optical lens. More specifically, 0.62 < ∑CT / TTL < 0.74.

[0067] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.7 < f1 / f < 3.3. Meeting the above range, by setting the first lens to have a positive refractive power, the incident light can be converged, and more light can enter the system, which is beneficial to increasing the light input of the lens and enabling the lens to achieve high-definition imaging even in a darker environment. More specifically, 1.92 < f1 / f < 3.

[0068] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.8 < f3 / f < 1.3. Meeting the above range, by reasonably setting the focal length of the third lens, it is beneficial to further converge the light, enabling the converged light to smoothly enter the rear optical system, reducing the difficulty of correcting the edge field distortion, and improving the overall imaging quality. More specifically, 0.91 < f3 / f < 1.14.

[0069] 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 < -0.5. Meeting the above range, by reasonably setting the focal length of the fourth lens, the positive spherical aberration generated by the fourth negative lens can be balanced with the negative spherical aberration generated by the previous positive lenses, improving the overall imaging quality. At the same time, the trend of the light can be reasonably controlled to avoid the problem of excessive lens sensitivity caused by excessive light deflection. More specifically, -0.66 < f4 / f < -0.6.

[0070] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.6 < f5 / f < 1.4. Meeting the above range can balance the lens aberration and improve the imaging quality. More specifically, 0.67 < f5 / f < 1.28.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: f6 / f < -1.5. Meeting the above range, defining that the sixth lens has a negative optical power is beneficial to increasing the imaging area of the optical lens. At the same time, it can optimize the chromatic aberration of the optical lens and improve the imaging quality of the optical lens. More specifically, f6 / f < -1.74.

[0072] In some embodiments, the effective focal length f of the optical lens and the combined focal length f12 of the first lens and the second lens satisfy: 2.1 < f12 / f < 3.9; the effective focal length f of the optical lens and the combined focal length f3456 of the third lens, the fourth lens, the fifth lens, and the sixth lens satisfy: 1.4 < f3456 / f < 2.7. Meeting the above range, by reasonably defining the focal lengths of the lens groups before and after the aperture, the aberration generated by the lens groups before and after the aperture can be effectively corrected, and the imaging quality of the optical lens can be improved. More specifically, 2.33 < f12 / f < 3.52; 1.53 < f3456 / f < 2.42.

[0073] In some embodiments, the optical lens satisfies the following conditional expressions: 12.6 mm < f < 17.9 mm; 24° < FOV < 30°; 5.7 mm < EPD < 9 mm; 29 mm < TTL < 35 mm; 1.8 < Fno < 2.4; 5.8 mm < IH < 8.8 mm; 16.5° < CRA < 21.1°; 3.5 mm < BFL < 5.3 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 overall 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 chief ray incident angle of the optical lens, and BFL represents the back focal length of the optical lens. Meeting the above range, the optical lens has at least one or more advantages such as a large target surface, a large aperture, and a long focal length characteristic. More specifically, 13.97 mm < f < 16.27 mm; 6.34 mm < EPD < 8.14 mm; 30.99 mm < TTL < 32.25 mm; 1.99 < Fno < 2.21; 18.28° < CRA < 19.21°; 4.05 mm < BFL < 4.78 mm; 25.9° < FOV < 28.1°; 6.3 mm < IH < 8 mm.

[0074] In some embodiments, the lens material in the optical lens provided by the present invention may be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. When the lens material is glass, the low dispersion characteristic of the glass itself can be used to effectively correct the geometric chromatic aberration of the optical system. 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.

[0075] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens may be spherical lenses or aspherical lenses. Compared with spherical structures, aspherical structures can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and reducing the size of lenses, and better realizing miniaturization of lenses. More specifically, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens of the present invention are spherical lenses.

[0076] The present invention is further described below in multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different. For specific differences, please refer to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any other changes, substitutions, combinations or simplifications that do not deviate from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0077] Example 1 See also Figure 1 , which is a schematic diagram of the structure of the optical lens provided in Embodiment 1 of the present invention, wherein the optical lens includes, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, an aperture ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a filter G1 and a protective glass G2.

[0078] The first lens L1 has positive refractive power, its object side surface S1 is convex, and its image side surface S2 is concave; The second lens L2 has positive refractive power, its object-side surface S3 is concave, and its image-side surface S4 is convex; The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is concave; The fourth lens L4 has negative refractive power, its object-side surface S6 is convex, and its image-side surface S7 is concave; The third lens L3 and the fourth lens L4 form a cemented lens group with negative power, that is, the cemented surface between the image side surface of the third lens L3 and the object side surface of the fourth lens L4 is S6; The fifth lens L5 has positive refractive power, its object-side surface S8 is convex, and its image-side surface S9 is concave; The sixth lens L6 has negative refractive power, its object-side surface S10 is concave, and its image-side surface S11 is convex; The object side surface S12 and the image side surface S13 of the filter G1 are both planes; The object side surface S14 and the image side surface S15 of the protective glass G2 are both planes; The imaging surface S16 is a plane.

[0079] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are glass spherical lenses.

[0080] The relevant parameters of each lens in the optical lens in Example 1 are shown in Table 1-1.

[0081] Table 1-1 In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical chromatic aberration curve, MTF curve, and relative illumination curve of the optical lens are shown as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 shown.

[0082] Figure 2 The field curvature curve of Example 1 is shown, which indicates the degree of curvature of light of different wavelengths on the meridional image plane and the sagittal image plane, the horizontal axis indicates the offset (unit: mm), and the vertical axis indicates the half field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.04mmmm, indicating that the optical lens can correct the field curvature well.

[0083] Figure 3 The F-Tan (Theta) distortion curve of Example 1 is shown, which represents the distortion of light of different wavelengths at different image heights on the imaging surface, with the horizontal axis representing the distortion value (unit: %) and the vertical axis representing the half field angle (unit: °). It can be seen from the figure that the distortion of the optical lens is controlled within ±2%, indicating that the optical lens can correct the distortion well.

[0084] Figure 4 The axial aberration curve of the optical lens in this embodiment is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the offset of the axial aberration is controlled within ±0.04mm, indicating that the optical lens can correct the axial aberration well.

[0085] Figure 5 The vertical axis chromatic aberration curve of the optical lens in this embodiment is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55μm) at different image heights on the imaging surface, the horizontal axis represents the vertical axis chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1.5μm, indicating that the optical lens can correct chromatic aberration well.

[0086] Figure 6 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF value of this embodiment is above 0.2 in the entire field of view, and in the range of 0 to 240 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency conditions.

[0087] Figure 7 The relative illumination curve of Example 1 is shown, which represents the relative illumination values ​​at different field angles on the imaging plane, with the horizontal axis representing the half field angle (unit: °) and the vertical axis representing the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 85% at the maximum half field angle, indicating that the optical lens has good relative illumination.

[0088] Example 2 See also Figure 8 , which is a schematic diagram of the structure of the optical lens provided in Example 2 of the present invention. Compared with Example 1, this embodiment mainly differs in that: the object-side surface S10 of the sixth lens L6 is a convex surface; the image-side surface S11 of the sixth lens L6 is a concave surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0089] The relevant parameters of each lens in the optical lens in Example 2 are shown in Table 2-1.

[0090] Table 2-1 In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical chromatic aberration curve, MTF curve, and relative illumination curve of the optical lens are shown as follows: Fig. 9 , Fig.10 , Fig.11 , Fig.12 , Fig.13 , Fig.14 shown.

[0091] from Fig. 9 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.04mmmm, indicating that the optical lens can correct the field curvature well.

[0092] from Fig.10 It can be seen that the distortion of the optical lens is controlled within ±2%, which means that the optical lens can correct the distortion well.

[0093] from Fig.11 It can be seen that the offset of axial aberration is controlled within ±0.04mm, which means that the optical lens can correct axial aberration well.

[0094] from Fig.12 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1.5μm, indicating that the optical lens can correct chromatic aberration well.

[0095] from Fig.13 It can be seen that the MTF value of this embodiment is above 0.3 in the whole field of view. In the range of 0 to 240 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0096] from Fig.14 It can be seen that at the maximum half field of view angle, the relative illumination value of the optical lens is still greater than 88%, indicating that the optical lens has good relative illumination.

[0097] Example 3 See also Fig.15 , which is a schematic diagram of the structure of an optical lens provided in Example 3 of the present invention. Compared with Example 1, this embodiment mainly differs in that: the image side surface S2 of the first lens L1 is a convex surface; the object side surface S10 of the sixth lens L6 is a convex surface; the image side surface S11 of the sixth lens L6 is a concave surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0098] The relevant parameters of each lens in the optical lens in Example 3 are shown in Table 3-1.

[0099] Table 3-1 In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical chromatic aberration curve, MTF curve, and relative illumination curve of the optical lens are shown as follows: Fig.16 , Fig.17 , Fig.18 , Fig.19 , Fig. 20 , Fig.21shown.

[0100] from Fig.16 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.04mmmm, indicating that the optical lens can correct the field curvature well.

[0101] from Fig.17 It can be seen that the distortion of the optical lens is controlled within ±1%, which means that the optical lens can correct the distortion well.

[0102] from Fig.18 It can be seen that the offset of axial aberration is controlled within ±0.04mm, which means that the optical lens can correct axial aberration well.

[0103] from Fig.19 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2μm, indicating that the optical lens can correct chromatic aberration well.

[0104] from Fig. 20 It can be seen that the MTF value of this embodiment is above 0.2 in the whole field of view. In the range of 0 to 240 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0105] from Fig.21 It can be seen that at the maximum half field of view angle, the relative illumination value of the optical lens is still greater than 90%, indicating that the optical lens has good relative illumination.

[0106] Please refer to Table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the real image height IH corresponding to the maximum field of view angle, the chief ray incident angle CRA at the maximum image height, the maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0107] Table 4 In summary of the above embodiments, the optical lens provided by the present invention adopts six lenses with specific optical powers. Through specific surface shape matching 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 long focus, large target area, and high imaging quality.

[0108] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0109] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical lens, comprising six lenses, characterized in that: From the object side to the imaging surface along the optical axis, it successively includes: A first lens with positive optical power, whose object side is convex. A second lens with positive optical power, whose object side is concave and whose image side is convex. A third lens with positive optical power, whose object side is convex and whose image side is concave. A fourth lens with negative optical power, whose object side is convex and whose image side is concave. A fifth lens with positive optical power, whose object side is convex and whose image side is concave. A sixth lens with negative optical power. Wherein, the radius of curvature R5 of the object side of the third lens and the radius of curvature R6 of the image side of the third lens satisfy: -0.9 < (R5 - R6) / (R5 + R6) < -0.

4.

2. The optical lens according to claim 1, characterized in that: The maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 10.7° < FOV / Fno < 15.5°; The total optical length TTL of the optical lens, the maximum field of view FOV of the optical lens and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 103 < 180°×TTL / IH / FOV < 135.

3. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: f2 / f > 20.

4. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the radius of curvature R5 of the object side of the third lens satisfy: 0.4 < R5 / f < 0.8; The effective focal length f of the optical lens and the radius of curvature R6 of the image side of the third lens satisfy: 2.7 < R6 / f < 3.

9.

5. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the radius of curvature R7 of the object side of the fourth lens satisfy: 2.7 < R7 / f < 3.9; The effective focal length f of the optical lens and the radius of curvature R8 of the image side of the fourth lens satisfy: 0.3 < R8 / f < 0.

6.

6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the radius of curvature R9 of the object side of the fifth lens satisfy: 0.5 < R9 / f < 1; The effective focal length f of the optical lens and the radius of curvature R10 of the image side of the fifth lens satisfy: 2.7 < R10 / f < 3.

9.

7. The optical lens according to claim 1, characterized in that: The radius of curvature R11 of the object side of the sixth lens and the radius of curvature R12 of the image side of the sixth lens satisfy: 0.5 < R11 / R12 < 1.

3.

8. The optical lens according to claim 1, characterized in that: 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: 0.5 < (R7 - R8) / (R7 + R8) < 0.

9.

9. The optical lens according to claim 1, characterized in that: The radius of curvature R9 of the object side of the fifth lens and the radius of curvature R10 of the image side of the fifth lens satisfy: -0.9 < (R9 - R10) / (R9 + R10) < -0.

5.

10. The optical lens according to claim 1, characterized in that: The sagittal height Sag5 of the clear aperture of the object side of the third lens and the clear aperture diameter d5 of the object side of the third lens satisfy: 0.1 < Sag5 / d5 < 0.35; The sagittal height Sag6 of the clear aperture of the image side of the third lens and the clear aperture diameter d6 of the image side of the third lens satisfy: 0 < Sag6 / d6 < 0.1.

Images