Optical lens

Abstract

The invention provides an optical lens, which comprises seven lenses in total, and sequentially comprises 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 object side surface and the image side surface of the second lens are convex surfaces; the object side surface and the image side surface of the third lens are convex surfaces; the fourth lens has negative focal power, and the object side surface of the fourth lens is a concave surface; the fifth lens has positive focal power, and the object side surface and the image side surface of the fifth lens are convex surfaces; the object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a concave surface; and the object side surface and the image side surface of the seventh lens are concave surfaces. According to the optical lens provided by the invention, through specific surface shape matching and reasonable focal power distribution, the lens has one or more advantages of long focus, large aperture, high imaging quality and the like.

Description

Technical Field

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

[0002] As people's requirements for driving experience continue to increase, automotive optical lenses are increasingly used in intelligent driving, and the status of automotive optical lenses in the automotive-related industries continues to improve.

[0003] Advanced driver assistance systems (ADAS) play an important role in intelligent driving. They use various lenses and sensors to collect environmental information to ensure the driver's driving safety. In addition to requiring the optical lens to be thin and short and have high pixels and high resolution, the existing ADAS system lens also requires the optical lens to be able to image clearly under low illumination conditions. Therefore, it is necessary to develop an optical lens with good imaging effect. Summary of the invention

[0004] In view of the above problems, an object of the present invention is to provide an optical lens having the advantage of excellent imaging quality.

[0005] The technical solution adopted by the present invention is: An optical lens, comprising seven lenses, which include: The first lens has a negative optical power, the object side surface of which is concave and the image side surface of which is convex; The second lens has positive refractive power, and its object side surface and image side surface are both convex; The third lens has positive refractive power, and both the object side surface and the image side surface are convex; a fourth lens element having negative optical power and a concave object side surface; A fifth lens having positive refractive power, whose object-side surface and image-side surface are both convex; a sixth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is concave; The seventh lens element has negative optical power, and both the object side surface and the image side surface are concave; The object-side curvature radius R11 of the sixth lens and the image-side curvature radius R12 of the sixth lens satisfy: -0.9<(R11-R12) / (R11+R12)<-0.3.

[0006] More preferably, the true image height IH corresponding to the maximum field of view angle of the optical lens, the effective focal length f of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.96 < (IH / 2) / (f×Tan(FOV / 2)) < 0.99; the overall optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.57 / ° < TTL / (IH / 2) / (FOV / 2) < 0.63 / °.

[0007] 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: 0.51 < IH / f < 0.55; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.23 < BFL / f < 0.27.

[0008] More preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.6 < f1 / f < -1.1; the object-side curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: -0.9 < R1 / f < -0.8; the image-side curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: -9.6 < R2 / f < -3.

[0009] More preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.25 < f2 / f < 1.45; the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1 < f3 / f < 1.1.

[0010] More preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.5 < f6 / f < 2.7; the object-side curvature radius R11 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.1 < R11 / f < 1.6; the image-side curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: 2.3 < R12 / f < 16.4.

[0011] More preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -0.75 < f7 / f < -0.6; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -0.65 < R13 / f < -0.5; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.7 < R14 / f < 11.7.

[0012] Further preferably, the combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens and the combined focal length f567 of the fifth lens, the sixth lens, and the seventh lens satisfy: 1.4 < f1234 / f567 < 2.9.

[0013] Further preferably, the radius of curvature R13 of the object side surface of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy: -1 < (R13 + R14) / (R13 - R14) < -0.4.

[0014] Further preferably, the clear aperture semi-diameter d12 of the image side surface of the sixth lens and the sagittal height Sag12 of the image side surface of the sixth lens satisfy: 0 < Sag12 / d12 < 0.06; the clear aperture semi-diameter d13 of the object side surface of the seventh lens and the sagittal height Sag13 of the object side surface of the seventh lens satisfy: -0.25 < Sag13 / d13 < -0.21.

[0015] The optical lens provided by the present invention uses seven lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power distributions, it can improve the imaging quality of the optical lens, reduce aberration, and improve the imaging quality of the optical lens, enabling the lens to have one or more advantages such as long focal length, large aperture, 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 be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, where: Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0017] Figure 2 is the field curvature curve graph of the optical lens in Embodiment 1 of the present invention.

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

[0019] Figure 4 is the axial aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0020] Figure 5 is the lateral chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0021] Figure 6 is the MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0022] Figure 7 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0023] Figure 8 Graph showing the field curvature of the optical lens in Embodiment 2 of the present invention.

[0024] Fig. 9 : is the F-Tan (Theta) distortion curve of the optical lens in Example 2 of the present invention.

[0025] Fig.10 Graph showing the axial aberration of the optical lens in Embodiment 2 of the present invention.

[0026] Fig.11 Graph showing the vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0027] Fig.12 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0028] Fig.13 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0029] Fig.14 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0030] Fig.15 : is the F-Tan (Theta) distortion curve of the optical lens in Example 3 of the present invention.

[0031] Fig.16 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0032] Fig.17 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0033] Fig.18 This is the MTF curve diagram of the optical lens in Example 3 of the present invention.

[0034] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] The optical lens provided by the embodiment of the present invention is composed of seven lenses, which are a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens in order from the object side to the imaging surface along the optical axis.

[0043] In some embodiments, the first lens may have a negative optical power, and its object side surface is concave, and its image side surface is convex. The second lens may have a positive optical power, and its object side surface and image side surface are both convex. The third lens may have a positive optical power, and its object side surface and image side surface are both convex. The fourth lens may have a negative optical power, and its object side surface is concave, and its image side surface may be concave or convex. The fifth lens may have a positive optical power, and its object side surface and image side surface are both convex. The sixth lens may have a positive optical power, and its object side surface is convex, and its image side surface is concave. The seventh lens may have a negative optical power, and its object side surface and image side surface are both concave.

[0044] In some embodiments, the optical lens may further include an aperture, which may be located between the fourth lens and the fifth lens. It is understandable that the aperture is used to limit the amount of light entering to change the brightness of the image. In addition, when the aperture is located between the fourth lens and the fifth lens, the aperture can reasonably distribute the effects of the first lens to the seventh lens. For example, the first lens, the second lens, the third lens, and the fourth lens can be used to receive light to a greater extent, and the fifth lens to the seventh lens can be used to correct aberrations, which is beneficial to balancing the structure of the entire optical system. In addition, when the aperture is located between the fourth lens and the fifth lens, it is convenient to correct the aperture aberration.

[0045] In some embodiments, the optical lens may further include a filter and a protective glass, and the filter and the protective glass may be sequentially arranged between the seventh lens and the imaging surface along the optical axis. The filter is used to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging. The protective glass plays a role in protecting the optical lens, preventing the photosensitive chip from being damaged, and can improve the impact resistance and scratch resistance of the optical lens, while having almost no effect on the imaging quality of the optical lens.

[0046] In some embodiments, the third lens and the fourth lens can be glued to form a glued 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 difficulty of the processing technology of the optical lens and improving the assembly yield of the optical lens.

[0047] In some embodiments, 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: -0.9 < (R11 - R12) / (R11 + R12) < -0.3. Satisfying the above range can make the object side surface and the image side surface close to a concentric circle structure, which is beneficial to make the light enter the rear lens smoothly, can reduce the field curvature, correct the off-axis aberration, and is beneficial to the correction of the aberration of the entire optical lens, improving the imaging quality of the optical lens. More specifically, -0.83 < (R11 - R12) / (R11 + R12) < -0.33.

[0048] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens, the effective focal length f of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.96 < (IH / 2) / (f × Tan(FOV / 2)) < 0.99. Satisfying the above range can control the optical lens to have a small distortion and improve the imaging quality.

[0049] In some embodiments, the overall optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.57 / ° < TTL / (IH / 2) / (FOV / 2) < 0.63 / °. Satisfying the above range can limit the length of the optical lens under the condition of the same imaging area and the same field of view angle, realizing the miniaturization of the optical lens.

[0050] 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: 0.51 < IH / f < 0.55. Satisfying the above range can control the image height and focal length of the optical lens within a reasonable range, which helps the optical lens to have the characteristic of a large image plane and improve the imaging quality.

[0051] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.23 < BFL / f < 0.27. Satisfying the above range can define that the optical lens has an appropriate back focus, which is convenient for arranging the positions of the lenses reasonably and reducing the processing and assembly difficulty at the same time.

[0052] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.6 < f1 / f < -1.1; 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: -0.9 < R1 / f < -0.8; 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: -9.6 < R2 / f < -3. Meeting the above ranges, by setting the first lens to have a negative refractive power and a suitable surface shape, it is beneficial for the first lens to receive a larger angle of light and collect as much light as possible to enter the rear optical system, increasing the light flux while achieving a large field of view. More specifically, -1.6 < f1 / f < -1.14; -0.86 < R1 / f < -0.83; -9.57 < R2 / f < -3.05.

[0053] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.25 < f2 / f < 1.45. Meeting the above ranges, it is defined that the second lens has an appropriate positive optical power, which has the effect of converging light, reducing the height of peripheral light, being beneficial for reducing the aperture of the rear lens, and at the same time being beneficial for balancing aberrations and improving resolution. More specifically, 1.29 < f2 / f < 1.41.

[0054] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1 < f3 / f < 1.1. Meeting the above ranges, it is defined that the third lens has an appropriate positive optical power, and the light is further converged. And gluing the third lens with a positive optical power and the fourth lens with a negative optical power is beneficial for the light to enter the rear lens smoothly, can adjust the optical path difference between different fields of view, and improve resolution. More specifically, 1.01 < f3 / f < 1.09.

[0055] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.5 < f6 / f < 2.7; the radius of curvature R11 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 1.1 < R11 / f < 1.6; the radius of curvature R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 2.3 < R12 / f < 16.4. Meeting the above ranges, it is defined that the sixth lens has a positive optical power and a suitable surface shape, which is beneficial for light convergence, enables the light trend to transition smoothly to the rear, reduces the height of the light incident on the rear, slows down the upward trend of the light, avoids light energy loss caused by too large an angle between the main light ray of the large field of view light and the chip when reaching the imaging surface, is beneficial for improving the illuminance of the edge field of view, and is beneficial for achieving a short optical total length. More specifically, 1.55 < f6 / f < 2.62; 1.13 < R11 / f < 1.6; 2.3 < R12 / f < 16.32.

[0056] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -0.75 < f7 / f < -0.6; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -0.65 < R13 / f < -0.5; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.7 < R14 / f < 11.7. Meeting the above ranges can effectively balance various aberrations generated by the front lens group, and at the same time is conducive to increasing the divergence degree of light, increasing the area of light entering the imaging surface, realizing large-format imaging of the lens, and improving the imaging quality of the optical lens. More specifically, -0.71 < f7 / f < -0.62; -0.61 < R13 / f < -0.53; 1.75 < R14 / f < 11.62.

[0057] In some embodiments, the combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens and the combined focal length f567 of the fifth lens, the sixth lens, and the seventh lens satisfy: 1.4 < f1234 / f567 < 2.9. Meeting the above ranges is conducive to balancing various aberrations of the system and improving the overall imaging quality by reasonably setting the relationship between the lens groups before and after the aperture. More specifically, 1.42 < f1234 / f567 < 2.84.

[0058] In some embodiments, the object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -1 < (R13 + R14) / (R13 - R14) < -0.4. Meeting the above ranges and controlling the surface shape of the seventh lens are conducive to increasing the imaging area and field of view angle of the optical lens, conducive to balancing the aberrations of the optical lens, and improving the imaging quality of the optical lens. More specifically, -0.92 < (R13 + R14) / (R13 - R14) < -0.48.

[0059] In some embodiments, the image-side clear aperture semi-diameter d12 of the sixth lens and the image-side clear aperture sagitta Sag12 of the sixth lens satisfy: 0 < Sag12 / d12 < 0.06; the object-side clear aperture semi-diameter d13 of the seventh lens and the object-side clear aperture sagitta Sag13 of the seventh lens satisfy: -0.25 < Sag13 / d13 < -0.21. Meeting the above ranges helps to control the trend of marginal field light and highlight the detailed information of the central field of the optical lens.

[0060] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.4 < TTL / f < 2.5. Meeting the above ranges can effectively limit the length of the lens while achieving a long focal length, which is conducive to the miniaturization of the optical lens. More specifically, 2.41 < TTL / f < 2.5.

[0061] In some embodiments, 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: 4.4 < TTL / IH < 4.7. Meeting the above range ensures that, with the same total length of the lens, a larger image plane is obtained, enabling it to match an imaging chip of a larger size to achieve high-definition imaging, and better achieving the balance between the small total length and the large image plane of the lens. More specifically, 4.49 < TTL / IH < 4.63.

[0062] In some embodiments, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 17° < FOV / Fno < 19°. Meeting the above range defines that the optical lens has an appropriate field of view angle and aperture value, enabling it to collect light at large angles and obtain good imaging quality. More specifically, 17.21° < FOV / Fno < 18.76°.

[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: 0.8 < IH / EPD < 1. Meeting the above range can increase the width of the light beam incident on the optical lens, improving the brightness at the image plane of the optical lens and avoiding vignetting. More specifically, 0.83 < IH / EPD < 0.98.

[0064] In some embodiments, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis satisfy: 0.6 < ∑CT / TTL < 0.65. Meeting the above range can effectively compress the total length of the optical lens, while being beneficial to the structural design and production process of the optical lens.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -1 < f4 / f < -0.8. Meeting the above range defines that the fourth lens has an appropriate negative optical power, which can diverge the light rays emitted by the third lens, making the light rays in the marginal field of view show an upward trend, facilitating the image points on the imaging plane to be away from the optical axis, which is beneficial to achieving the effect of matching with a large chip, obtaining a larger picture, effectively eliminating aberrations, and improving the resolution ability of the optical lens. More specifically, -1.11 < f4 / f < -0.86.

[0066] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.21 < f5 / f < 1.42; the radius of curvature R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 0.7 < R9 / f < 0.9; the radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -3.6 < R10 / f < -1.9. Satisfying the above ranges and setting the fifth lens to have positive refractive power and a suitable surface shape is beneficial for converging light while correcting the field curvature and distortion of the optical lens, and improving the imaging quality of the optical lens. More specifically, 1.21 < f5 / f < 1.42; 0.71 < R9 / f < 0.84; -3.51 < R10 / f < -1.99.

[0067] 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: -0.7 < (R9 + R10) / (R9 - R10) < -0.4. Satisfying the above range is beneficial for the smooth transition of light, can effectively correct the distortion of the edge field of view, reduce the deformation degree of the edge of the captured picture, and improve the picture quality. More specifically, -0.67 < (R9 + R10) / (R9 - R10) < -0.41.

[0068] In some embodiments, the optical lens satisfies the following conditional expressions: 12 mm < f < 13.5 mm; 29° < FOV < 32°; 7 mm < EPD < 8.2 mm; 30 mm < TTL < 32 mm; 1.5 < Fno < 1.9; 6.5 mm < IH < 7 mm; 21° < CRA < 23°; 3.1 mm < BFL < 3.2 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. Satisfying the above ranges, 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, 12.25 mm < f < 13.06 mm; 7.02 mm < EPD < 8.17 mm; 30.56 mm < TTL < 31.65 mm; 1.59 < Fno < 1.81; 21.14° < CRA < 22.62°; 3.17 mm < BFL < 3.19 mm; 29.9° < FOV < 31.1°; 6.62 mm < IH < 6.85 mm.

[0069] 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 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.

[0070] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh 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, the sixth lens, and the seventh lens of the present invention are spherical lenses.

[0071] 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.

[0072] Example 1 See also Figure 1 , shown is a schematic diagram of the structure of the optical lens 100 provided in Example 1 of the present invention, and the optical lens 100 includes, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1 and a protective glass G2.

[0073] The first lens L1 has negative refractive power, its object side surface S1 is concave, and its image side surface S2 is convex; The second lens L2 has positive refractive power, its object-side surface S3 is convex, and its image-side surface S4 is convex; The third lens L3 has positive refractive power, and its object side surface S5 and image side surface are both convex; The fourth lens L4 has negative refractive power, its object side surface is concave, 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, and its object-side surface S8 and image-side surface S9 are both convex surfaces; The sixth lens L6 has positive refractive power, an object-side surface S10 thereof is convex, and an image-side surface S11 thereof is concave; The seventh lens L7 has negative refractive power, its object-side surface S12 is concave, and its image-side surface S13 is concave; The object side surface S14 and the image side surface S15 of the filter G1 are both planes; The object side surface S16 and the image side surface S17 of the protective glass G2 are both flat surfaces; The imaging surface S18 is a plane.

[0074] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are glass spherical lenses.

[0075] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1.

[0076] Table 1 In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical axis chromatic aberration curve, and MTF curve of the optical lens 100 are shown as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 shown.

[0077] 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 -0.02mm~0.04mm, indicating that the optical lens can well correct the field curvature.

[0078] Figure 3 The F-Tan (Theta) distortion curve of Example 1 is shown, which represents the F-Tan (Theta) distortion of light of different wavelengths at different image heights on the imaging surface, the horizontal axis represents the F-Tan (Theta) distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the F-Tan (Theta) distortion of the optical lens is controlled within -3%~0, indicating that the optical lens can correct the distortion well.

[0079] Figure 4The axial aberration curve of Example 1 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the offset of the axial aberration is controlled within -0.01mm~0.04mm, indicating that the optical lens can correct the axial aberration well.

[0080] Figure 5 The vertical chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -1 μm~2 μm, indicating that the optical lens can correct chromatic aberration very well.

[0081] 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 0.38 in the entire field of view, and in the range of 0 to 180 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.

[0082] Example 2 See also Figure 7 , shown is a schematic diagram of the structure of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0083] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2.

[0084] Table 2 In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical axis chromatic aberration curve, and MTF curve of the optical lens 200 are shown as follows: Figure 8 , Fig. 9 , Fig.10 , Fig.11 , Fig.12 shown.

[0085] from Figure 8 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within -0.02mm~0.03mm, indicating that the optical lens 200 can correct the field curvature well.

[0086] from Fig. 9 It can be seen that the F-Tan (Theta) distortion of the optical lens 200 is controlled within -3%~0, indicating that the optical lens 200 can correct the distortion well.

[0087] from Fig.10 It can be seen that the offset of the axial aberration is controlled within -0.01mm~0.03mm, which means that the optical lens 200 can correct the axial aberration well.

[0088] from Fig.11 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -1μm~2μm, indicating that the optical lens 200 can correct chromatic aberration very well.

[0089] from Fig.12 It can be seen that the MTF value of this embodiment is above 0.38 in the whole field of view. In the range of 0 to 180 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.

[0090] Example 3 See also Fig.13 , shown is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main differences of this embodiment are: the third lens L3 and the fourth lens L4 form a cemented lens group with positive focal length; the image side surface S7 of the fourth lens L4 is a convex surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0091] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3.

[0092] Table 3 In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical axis chromatic aberration curve, and MTF curve of the optical lens 300 are shown as follows: Fig.14 , Fig.15 , Fig.16 , Fig.17 , Fig.18 shown.

[0093] from Fig.14 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within -0.01mm~0.03mm, indicating that the optical lens 300 can correct the field curvature well.

[0094] from Fig.15It can be seen that the F-Tan (Theta) distortion of the optical lens 300 is controlled within -3%~0, indicating that the optical lens 300 can correct the distortion well.

[0095] from Fig.16 It can be seen that the offset of the axial aberration is controlled within -0.01mm~0.03mm, which means that the optical lens 300 can correct the axial aberration well.

[0096] from Fig.17 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -1μm~2μm, indicating that the optical lens 300 can correct chromatic aberration very well.

[0097] from Fig.18 It can be seen that the MTF value of this embodiment is above 0.48 in the whole field of view. In the range of 0 to 180 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.

[0098] Please refer to Table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the real image height IH corresponding to the maximum field of view angle, the maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0099] Table 4 In summary of the above embodiments, the optical lens provided by the present invention adopts seven 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 telephoto, large aperture, and high imaging quality.

[0100] 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.

[0101] 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 seven lenses, characterized in that: It successively includes from the object side to the imaging plane along the optical axis: A first lens with a negative optical power, whose object side is concave and whose image side is convex; A second lens with a positive optical power, whose object side and image side are both convex; A third lens with a positive optical power, whose object side and image side are both convex; A fourth lens with a negative optical power, whose object side is concave; A fifth lens with a positive optical power, whose object side and image side are both convex; A sixth lens with a positive optical power, whose object side is convex and whose image side is concave; A seventh lens with a negative optical power, whose object side and image side are both concave; Wherein, the curvature radius R11 of the object side of the sixth lens and the curvature radius R12 of the image side of the sixth lens satisfy: -0.9 < (R11 - R12) / (R11 + R12) < -0.

3.

2. The optical lens according to claim 1, characterized in that: The true image height IH corresponding to the maximum field of view angle of the optical lens, the effective focal length f of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.96 < (IH / 2) / (f×Tan(FOV / 2)) < 0.99; The total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.57 / ° < TTL / (IH / 2) / (FOV / 2) < 0.63 / °.

3. 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: 0.51 < IH / f < 0.55; The effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.23 < BFL / f < 0.

27.

4. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.6 < f1 / f < -1.1; The curvature radius R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: -0.9 < R1 / f < -0.8; The curvature radius R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: -9.6 < R2 / f < -3.

5. 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: 1.25 < f2 / f < 1.45; The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1 < f3 / f < 1.

1.

6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1.5 < f6 / f < 2.7; The curvature radius R11 of the object side of the sixth lens and the effective focal length f of the optical lens satisfy: 1.1 < R11 / f < 1.6; The curvature radius R12 of the image side of the sixth lens and the effective focal length f of the optical lens satisfy: 2.3 < R12 / f < 16.

4.

7. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -0.75 < f7 / f < -0.6; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -0.65 < R13 / f < -0.5; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.7 < R14 / f < 11.

7.

8. The optical lens according to claim 1, characterized in that: The combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens and the combined focal length f567 of the fifth lens, the sixth lens, and the seventh lens satisfy: 1.4 < f1234 / f567 < 2.

9.

9. The optical lens according to claim 1, characterized in that: The object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -1 < (R13 + R14) / (R13 - R14) < -0.

4.

10. The optical lens according to claim 1, characterized in that: The image-side clear aperture semi-diameter d12 of the sixth lens and the image-side clear aperture sagitta Sag12 of the sixth lens satisfy: 0 < Sag12 / d12 < 0.06; the object-side clear aperture semi-diameter d13 of the seventh lens and the object-side clear aperture sagitta Sag13 of the seventh lens satisfy: -0.25 < Sag13 / d13 < -0.21.

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