Optical lens

Abstract

The present invention provides an optical lens, which sequentially includes, along the optical axis from the object side to the imaging surface: a first lens with a negative optical power, whose object side surface is concave and image side surface is concave; a second lens with a positive optical power, and the second lens is a meniscus lens; a third lens with an optical power, whose object side surface is convex and image side surface is concave; a fourth lens with a positive optical power, whose object side surface is convex and image side surface is convex; a fifth lens with a positive optical power, whose object side surface is concave and image side surface is convex; a sixth lens with a negative optical power, whose object side surface is convex near the optical axis and image side surface is concave near the optical axis; the curvature radius R3 of the object side surface of the second lens and the curvature radius of the image side surface of the second lens satisfy: 0.5 < R3 / R4 < 2; the curvature radius R1 of the object side surface of the first lens and the curvature radius R2 of the image side surface of the first lens satisfy: -0.9 < (R1 + R2) / (R1 - R2) < -0.1. The optical lens provided by the present invention can reasonably correct the overall aberration of the optical lens and improve the imaging quality of the optical lens.

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] The in-vehicle DMS system camera belongs to an imaging camera and is mainly applied to the cabin. Its main functions include driver fatigue detection, face recognition, etc. In addition to requiring the optical lens to have a thin and light shape, a small front aperture diameter, high pixel, high resolution and other characteristics, the existing DMS system lens also requires 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 with the advantage of excellent imaging quality.

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

[0006] An optical lens, comprising a total of six lenses, which are sequentially arranged from the object side to the imaging surface along the optical axis:

[0007] A first lens with a negative optical power, the object side surface of which is concave and the image side surface of which is concave;

[0008] A second lens with a positive optical power, the second lens being a meniscus lens;

[0009] A third lens with an optical power, the object side surface of which is convex and the image side surface of which is concave;

[0010] A fourth lens with a positive optical power, the object side surface of which is convex and the image side surface of which is convex;

[0011] A fifth lens with a positive optical power, the object side surface of which is concave and the image side surface of which is convex;

[0012] A sixth lens with a negative optical power, the object side surface of which is convex near the optical axis and the image side surface of which is concave near the optical axis;

[0013] Wherein, the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: 0.5 < R3 / R4 < 2; the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R2 of the image side surface of the first lens satisfy: -0.9 < (R1 + R2) / (R1 - R2) < -0.1.

[0014] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2 < TTL / f < 2.4.

[0015] Further preferably, the maximum field of view FOV of the optical lens and the f-number Fno of the optical lens satisfy: 27° < FOV / Fno < 35°.

[0016] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 4.7 < f2 / f < 18.3.

[0017] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 10 < |f3 / f| < 55; the curvature radius R5 of the object side surface of the third lens, the curvature radius R6 of the image side surface of the third lens, and the central thickness CT3 of the third lens satisfy: 0.5 < (R5 - CT3) / R6 < 0.8.

[0018] Further preferably, the curvature radius R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 0.6 < R7 / f < 0.8; the curvature radius R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -4.4 < R8 / f < -3.5.

[0019] Further preferably, the curvature radius R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -5.2 < R9 / f < -2.6; the curvature radius R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -2.7 < R10 / f < -1.8.

[0020] Further preferably, the curvature radius R11 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 14.6 < R11 / f < 42.1; the curvature radius R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 0.7 < R12 / f < 1.

[0021] Further preferably, the sagittal height Sag1 of the object side surface clear aperture of the first lens and the object side surface clear aperture d1 of the first lens satisfy: -0.2 < Sag1 / d1 < -0.05; the sagittal height Sag11 of the object side surface clear aperture of the sixth lens and the object side surface clear aperture d11 of the sixth lens satisfy: -0.4 < Sag11 / d11 < -0.2.

[0022] Further preferably, the semi-aperture d1 of the object side of the first lens, the real image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 1.6 <d1 / (IH / 2) / tan(FOV / 2)<2.3。

[0023] Compared with the prior art, the optical lens provided by the present invention effectively shortens the overall length of the optical lens through a specific surface shape setting and a reasonable optical focal length distribution, which is conducive to miniaturization of the optical lens. At the same time, it has a large aperture and can achieve high-definition imaging even in dim environments. It can reasonably correct the overall aberration of the optical lens, reduce aberrations, improve the resolution of the optical lens, achieve high-definition imaging, and improve the imaging quality of the optical lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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:

[0025] Figure 1 Schematic diagram of the structure of the optical lens in Example 1 of the present invention.

[0026] Figure 2 It is a field curvature curve diagram of the optical lens in Example 1 of the present invention.

[0027] Figure 3 : is the F-Tanθ distortion curve of the optical lens in Example 1 of the present invention.

[0028] Figure 4 Graph showing the vertical axis chromatic aberration of the optical lens in Example 1 of the present invention.

[0029] Figure 5 Graph showing the axial aberration of the optical lens in Example 1 of the present invention.

[0030] Figure 6 This is the MTF curve diagram of the optical lens in Example 1 of the present invention.

[0031] Figure 7 This is a relative illumination curve diagram of the optical lens in Example 1 of the present invention.

[0032] Figure 8 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0033] Fig. 9 4 is a field curvature curve diagram of the optical lens in Example 2 of the present invention.

[0034] Fig.10 : is the F-Tanθ distortion curve of the optical lens in Example 2 of the present invention.

[0035] Fig.11Graph showing the vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0036] Fig.12 Graph showing the axial aberration of the optical lens in Embodiment 2 of the present invention.

[0037] Fig.13 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0038] Fig.14 This is a relative illumination curve diagram of the optical lens in Example 2 of the present invention.

[0039] Fig.15 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0040] Fig.16 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0041] Fig.17 : is the F-Tanθ distortion curve of the optical lens in Example 3 of the present invention.

[0042] Fig.18 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0043] Fig.19 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0044] Fig. 20 This is the MTF curve diagram of the optical lens in Example 3 of the present invention.

[0045] Fig.21 This is a relative illumination curve diagram of the optical lens in Example 3 of the present invention.

[0046] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] The optical lens provided in the embodiment of the present invention comprises six lenses in total, which include, in order from the object side to the imaging surface along the optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens.

[0055] In some embodiments, the first lens may have a negative focal power, with its object side being concave and its image side being concave. The second lens may have a positive focal power, and the second lens may be a meniscus lens. The third lens may have a positive or negative focal power, with its object side being convex and its image side being concave. The fourth lens may have a positive focal power, with its object side being convex and its image side being convex. The fifth lens may have a positive focal power, with its object side being concave and its image side being convex. The sixth lens may have a negative focal power, with its object side being convex near the optical axis and its image side being concave near the optical axis.

[0056] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the third lens and the fourth lens. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the imaging. When the diaphragm is located between the third lens and the fourth lens, it is convenient for correcting the diaphragm aberration.

[0057] 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 along the optical axis between the sixth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting the 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.

[0058] In some embodiments, the radius of curvature R3 of the object side of the second lens and the radius of curvature R4 of the image side of the second lens satisfy: 0.5 < R3 / R4 < 2. Meeting the above range, by adjusting the radii of curvature of the object side and the image side of the second lens, it is beneficial to strengthen the correction of higher-order aberrations and reduce the attenuation degree of the relative illumination of the optical lens. At the same time, the second lens adopts a meniscus shape, which is beneficial to correcting the distortion of the optical lens. More specifically, 0.59 < R3 / R4 < 1.91.

[0059] In some embodiments, the radius of curvature R1 of the object side of the first lens and the radius of curvature R2 of the image side of the first lens satisfy: -0.9 < (R1 + R2) / (R1 - R2) < -0.1. Meeting the above range can effectively reduce the working aperture of the first lens, which is beneficial to realizing the miniaturization of the optical lens. More specifically, more specifically, -0.72 < (R1 + R2) / (R1 - R2) < -0.28.

[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 < TTL / f < 2.4. Meeting the above range can effectively limit the length of the lens, which is beneficial to realizing the miniaturization of the optical lens. More specifically, 2.2 < TTL / f < 2.32.

[0061] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 27° < FOV / Fno < 35°. Meeting the above range is beneficial to expanding the field of view angle of the optical lens and increasing the aperture of the optical lens, which is beneficial for the optical lens to obtain more scene information and meet the requirements of large-range detection. The realization of the large-aperture characteristic is beneficial to improving the problem of rapid decline of the relative brightness in the edge field of view, enabling more light to enter, and being able to achieve high-definition imaging even in a dim environment, thus also being beneficial to obtaining more scene information. More specifically, 30.18° < FOV / Fno < 32.53°.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 4.7 < f2 / f < 18.3. Meeting the above range is beneficial to the smooth transition of light, and at the same time corrects various aberrations of the optical lens, improving the imaging quality of the optical lens. More specifically, 4.81 < f2 / f < 16.74.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 10 < |f3 / f| < 55. Meeting the above range makes the light trend smoother and optimizes the aberration. More specifically, 11.05 < |f3 / f| < 52.47.

[0064] In some embodiments, the curvature radius R5 of the object side surface of the third lens, the curvature radius R6 of the image side surface of the third lens, and the central thickness CT3 of the third lens satisfy: 0.5 < (R5 - CT3) / R6 < 0.8. Meeting the above range can reasonably control the surface shape and thickness of the third lens, reduce the correction difficulty of the edge field of view aberration, and improve the imaging quality of the optical lens.

[0065] In some embodiments, the curvature radius R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 0.6 < R7 / f < 0.8; the curvature radius R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -4.4 < R8 / f < -3.5. Meeting the above range can reasonably control the surface shape of the fourth lens, which is beneficial to reducing the aberration generated by the front lens and at the same time reducing the aberration correction difficulty of the rear lens. More specifically, 0.63 < R7 / f < 0.7; -4.01 < R8 / f < -3.79.

[0066] In some embodiments, 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: -5.2 < R9 / f < -2.6; 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: -2.7 < R10 / f < -1.8. Meeting the above ranges and reasonably controlling the surface shape of the fifth lens helps to further optimize astigmatism and field curvature and reduce the difficulty of correcting the higher-order aberrations of the subsequent lenses. More specifically, -4.86 < R9 / f < -2.79; -2.5 < R10 / f < -2.01.

[0067] In some embodiments, 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: 14.6 < R11 / f < 42.1; 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: 0.7 < R12 / f < 1. Meeting the above ranges and reasonably controlling the surface shape of the sixth lens is beneficial to increasing the field of view angle and the imaging area. More specifically, 16.26 < R11 / f < 38.38; 0.78 < R12 / f < 0.88.

[0068] In some embodiments, the sagittal height Sag1 of the object side surface clear aperture of the first lens and the object side surface clear aperture d1 of the first lens satisfy: -0.2 < Sag1 / d1 < -0.05; the sagittal height Sag11 of the object side surface clear aperture of the sixth lens and the object side surface clear aperture d11 of the sixth lens satisfy: -0.4 < Sag11 / d11 < -0.2. Meeting the above ranges can reduce the difficulty of correcting aberrations in the marginal field of view. More specifically, -0.17 < Sag1 / d1 < -0.08; -0.31 < Sag11 / d11 < -0.27.

[0069] In some embodiments, the object side surface clear aperture d1 of the first lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 1.6 < d1 / (IH / 2) / tan(FOV / 2) < 2.3. Meeting the above ranges can have a small front aperture while meeting the requirements of the optical lens having a large field of view angle and a large image plane. More specifically, 1.79 < d1 / (IH / 2) / tan(FOV / 2) < 2.06.

[0070] 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: 2 < TTL / IH < 2.4. Meeting the above ranges and reasonably restricting the ratio of the total length of the optical lens to the image height can ensure that the lens has a larger image plane under the same total length, achieving the balance between the miniaturization of the optical lens and the large image plane. More specifically, 2.19 < TTL / IH < 2.37.

[0071] In some embodiments, the effective focal length f of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.8 < (IH / 2) / (f×Tan(FOV / 2)) < 0.9. Meeting the above range controls the distortion of the optical lens within a reasonable range. More specifically, 0.8 < (IH / 2) / (f×Tan(FOV / 2)) < 0.86.

[0072] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1.8 < IH / EPD < 2.2. Meeting the above range enables the optical lens to meet the requirements of a large image plane and a large aperture, while also ensuring sufficient image plane brightness in the edge field of view, preventing vignetting, and thus improving the imaging quality. More specifically, 1.93 < IH / EPD < 2.03.

[0073] In some embodiments, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.9 < IH / / f < 1.1. Meeting the above range enables the optical lens to have the characteristic of a large image plane and can better achieve the high-definition imaging quality of the lens. More specifically, 0.97 < IH / f < 1.03.

[0074] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.3 < BFL / f < 0.45. Meeting the above conditions is conducive to achieving a balance between good imaging quality and an optical back focal length that is easy to assemble, ensuring the imaging quality of the optical lens while reducing the assembly process difficulty of the camera module. More specifically, 0.35 < BFL / f < 0.39.

[0075] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens, the maximum field of view angle FOV of the optical lens, and the effective focal length f of the optical lens satisfy: 58° < (FOV×f) / IH < 69°. Meeting the above range is conducive to achieving the balance of a large field of view angle and large target surface imaging of the optical lens by reasonably restricting the relationship between the focal length, field of view angle, and image height of the optical lens. More specifically, 60.88° < (FOV×f) / IH < 63.49°.

[0076] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -3 < f1 / f < -2.2. By satisfying the above range, by setting the first lens to have a large negative refractive power, it is possible to ensure that the first lens can receive a larger angle of light and collect as much light as possible into the rear optical system, achieving a large field of view while increasing the light flux and better realizing the large aperture performance of the lens. More specifically, -2.69 < f1 / f < -2.43.

[0077] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.7 < f4 / f < 0.9. By satisfying the above conditions, the fourth lens can have an appropriate positive optical power, which is beneficial to reducing the aberration generated by the front-end lens and at the same time reducing the difficulty of aberration correction for the rear-end lens. More specifically, 0.75 < f4 / f < 0.82.

[0078] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 8 < f5 / f < 15. By satisfying the above conditions, it helps the light to travel smoothly and improves the imaging quality. More specifically, 9.49 < f5 / f < 13.09.

[0079] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.9 < f6 / f < -1.4. By satisfying the above range, the sixth lens can have an appropriate negative optical power, which is beneficial to balancing the astigmatism and field curvature of the optical lens and improving the imaging quality of the optical lens. More specifically, -1.69 < f6 / f < -1.55.

[0080] In some embodiments, the combined focal length f123 of the first lens, the second lens, and the third lens and the effective focal length f of the optical lens satisfy: -6.6 < f123 / f < -3. By satisfying the above conditions, by reasonably setting the negative refractive power of the lens group in front of the aperture stop, it is beneficial to converge the light within a large angle range and at the same time improve the resolution of the edge field of view, achieving a balance between a shorter total length of the optical lens and good imaging quality. More specifically, -6.05 < f123 / f < -3.31.

[0081] In some embodiments, the combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens and the effective focal length f of the optical lens satisfy: 0.7 < f456 / f < 1. By satisfying the above conditions, by reasonably setting the positive refractive power of the lens group behind the aperture stop, it is beneficial to balance the distortion and astigmatism generated by the front-end lens of the optical lens and improve the imaging quality of the optical lens. More specifically, 0.76 < f456 / f < 0.89.

[0082] In some embodiments, the effective focal length f of the optical lens and the curvature radius R1 of the object side surface of the first lens satisfy: -3.4 < R1 / f < -1.7; the effective focal length f of the optical lens and the curvature radius R2 of the image side surface of the first lens satisfy: 3.2 < R2 / f < 16.9. Satisfying the above ranges, by reasonably setting the surface shape of the first lens, the light entering the first lens can have appropriate incident and exit angles, which is beneficial to reducing the outer diameter of the lens and maintaining the miniaturization of the system. More specifically, -3.12 < R1 / f < -1.94; 3.5 < R2 / f < 15.31.

[0083] In some embodiments, the curvature radius R9 of the object side surface of the fifth lens and the curvature radius R11 of the object side surface of the sixth lens satisfy: -1.6 < (R9 - R11) / (R9 + R11) < -1.1. Satisfying the above range, reasonably defining the shapes of the object side surface of the fifth lens and the image side surface of the sixth lens can effectively correct the aberration of the optical lens. More specifically, -1.43 < (R9 - R11) / (R9 + R11) < -1.28.

[0084] In some embodiments, the curvature radius R9 of the object side surface of the fifth lens and the curvature radius R10 of the image side surface of the fifth lens satisfy: 2.8 < (R9 + R10) / (R9 - R10) < 6.8. Satisfying the above range, reasonably defining the shapes of the object side surface and the image side surface of the fifth lens can control the fifth lens to have an appropriate surface shape and can effectively correct the aberration of the optical lens. More specifically, 3.1 < (R9 - R10) / (R9 + R10) < 6.22.

[0085] In some example embodiments, the sum ∑CT of the central thicknesses along the optical axis of the first lens to the sixth lens and the optical total length TTL of the optical lens satisfy: 0.4 < ∑CT / TTL < 0.6. Satisfying the above range can effectively compress the total length of the optical lens and is beneficial to the structural design and production process of the optical lens. More specifically, 0.47 < ∑CT / TTL < 0.56.

[0086] In some embodiments, the optical lens satisfies the conditional formula: 5.9 mm < f < 7.2 mm, 54° < FOV < 69°, 2.9 mm < EPD < 3.7 mm, 13.1 mm < TTL < 16.9 mm, 1.7 < Fno < 2.1, 6 mm < IH < 7.2 mm, 20.5° < CRA < 27.6°, 2.2 mm < BFL < 2.6 mm, where f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the principal ray incident angle at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least characteristics such as a small volume, a large image plane, and a large aperture. More specifically, 6.47 mm < f < 6.68 mm, 61.34° < FOV < 62.78°, 3.26 mm < EPD < 3.42 mm, 14.48 mm < TTL < 15.41 mm, 1.92 < Fno < 2.04, 6.5 mm < IH < 6.61 mm, 23.04° < CRA < 25.07°, 2.42 mm < BFL < 2.45 mm.

[0087] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. When the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. In the optical lens provided by the present invention, the first lens and the fourth lens are made of glass lenses, and the second lens, the third lens, the fifth lens, and the sixth lens are made of plastic lenses.

[0088] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens can be spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the first lens and the fourth lens of the present invention are spherical lenses, and the second lens, the third lens, the fifth lens, and the sixth lens can all be aspherical lenses, which can effectively reduce the aberration of the optical lens, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens.

[0089] In each embodiment of the present invention, when the lens is an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0090] ;

[0091] Among them, z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the surface vertex, K is the quadratic surface coefficient, B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients respectively.

[0092] 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.

[0093] Example 1

[0094] See also Figure 1 , which is a schematic diagram of the structure of the optical lens 100 provided in Embodiment 1 of the present invention, wherein 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, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a filter G1 and a protective glass G2.

[0095] The first lens L1 has negative refractive power, its object side surface S1 is concave, and its image side surface S2 is concave;

[0096] The second lens L2 has positive refractive power, its object-side surface S3 is concave, and its image-side surface S4 is convex;

[0097] The third lens L3 has negative refractive power, its object-side surface S5 is convex, and its image-side surface S6 is concave;

[0098] The fourth lens L4 has positive refractive power, its object-side surface S7 is convex, and its image-side surface S8 is convex;

[0099] The fifth lens L5 has positive refractive power, its object-side surface S9 is concave, and its image-side surface S10 is convex;

[0100] The sixth lens L6 has negative refractive power, an object-side surface S11 thereof is convex at the near optical axis, and an image-side surface S12 thereof is concave at the near optical axis;

[0101] The object side surface S13 and the image side surface S14 of the filter G1 are both planes;

[0102] The object side surface S15 and the image side surface S16 of the protective glass G2 are both flat surfaces;

[0103] The imaging surface S17 is a plane.

[0104] The first lens L1 and the fourth lens L4 are glass spherical lenses, and the second lens L2, the third lens L3, the fifth lens L5 and the sixth lens L6 are plastic aspherical lenses.

[0105] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0106] Table 1-1

[0107]

[0108] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0109] Table 1-2

[0110]

[0111] In this embodiment, the field curvature curve, F-Tanθ distortion curve, vertical axis chromatic aberration curve, axial aberration curve, MTF curve, and relative illumination curve of the optical lens 100 are shown as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 shown.

[0112] 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 -0.08mm~0, indicating that the optical lens can correct the field curvature well.

[0113] Figure 3 The F-Tanθ distortion curve of Example 1 is shown, which represents the F-Tanθ distortion of light of different wavelengths at different image heights on the imaging surface, the horizontal axis represents the F-Tanθ distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the F-Tanθ distortion of the optical lens is controlled within -20% to 0, the image compression in the edge angle area is relatively gentle, and the clarity of the expanded image is effectively improved.

[0114] Figure 4The vertical chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.546 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 ±0.4 μm, indicating that the optical lens can perfectly correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0115] Figure 5 The 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 ±0.03mm, indicating that the optical lens can correct the axial aberration well.

[0116] 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 0.3 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.

[0117] Figure 7 The relative illumination curve of Example 1 is shown, which represents the relative illumination values ​​at different viewing angles on the imaging plane, with the horizontal axis representing the half viewing 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 greater than 90%, indicating that the optical lens has good relative illumination.

[0118] Example 2

[0119] See also Figure 8 , 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.

[0120] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0121] Table 2-1

[0122]

[0123] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0124] Table 2-2

[0125]

[0126] In this embodiment, the field curvature curve, F-Tanθ distortion curve, vertical axis chromatic aberration curve, axial aberration curve, MTF curve, and relative illumination curve of the optical lens 200 are shown as follows: Fig. 9 , Fig.10 , Fig.11 , Fig.12 , Fig.13 , Fig.14 shown.

[0127] from Fig. 9 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within -0.08mm~0, indicating that the optical lens can correct the field curvature well.

[0128] from Fig.10 It can be seen that the F-Tanθ distortion of the optical lens is controlled within -20%~0, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the expanded image.

[0129] from Fig.11 It can be seen that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±0.4μm, indicating that the optical lens can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0130] from Fig.12 It can be seen that the offset of axial aberration is controlled within ±0.03mm, which means that the optical lens can correct axial aberration well.

[0131] 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 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.

[0132] from Fig.14 It can be seen that the relative illumination value of the optical lens is greater than 90%, indicating that the optical lens has good relative illumination.

[0133] Example 3

[0134] See also Fig.15, 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 has positive focal power; the object side surface S5 of the third lens L3 is a convex surface; the image side surface S6 of the third lens L3 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0135] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0136] Table 3-1

[0137]

[0138] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0139] Table 3-2

[0140]

[0141] In this embodiment, the field curvature curve, F-Tanθ distortion curve, vertical axis chromatic aberration curve, axial aberration curve, MTF curve, and relative illumination curve of the optical lens 300 are shown as follows: Fig.16 , Fig.17 , Fig.18 , Fig.19 , Fig. 20 , Fig.21 shown.

[0142] from Fig.16 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within -0.06mm~0, indicating that the optical lens can correct the field curvature well.

[0143] from Fig.17 It can be seen that the F-Tanθ distortion of the optical lens is controlled within -20%~0, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the expanded image.

[0144] from Fig.18 It can be seen that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±0.6μm, indicating that the optical lens can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0145] from Fig.19 It can be seen that the offset of axial aberration is controlled within ±0.02mm, which means that the optical lens can correct axial aberration well.

[0146] from Fig. 20It 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.

[0147] from Fig.21 It can be seen that the relative illumination value of the optical lens is greater than 90%, indicating that the optical lens has good relative illumination.

[0148] 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.

[0149] Table 4

[0150]

[0151]

[0152] The optical lens provided by the present invention effectively shortens the overall length of the optical lens through a specific surface shape setting and a reasonable distribution of optical focal length, which is conducive to miniaturization of the optical lens. At the same time, it has a large aperture and can achieve high-definition imaging even in a dim environment. It can reasonably correct the overall aberration of the optical lens, reduce the aberration, improve the resolution of the optical lens, achieve high-definition imaging, and improve the imaging quality of the optical lens.

[0153] 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.

[0154] 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: 依次包括沿光轴从物侧到成像面的: 第一透镜,具有负光焦度,其物侧面是凹面,其像侧面是凹面; 第二透镜,具有正光焦度,所述第二透镜是弯月透镜; 第三透镜,具有光焦度,其物侧面是凸面,其像侧面是凹面; 第四透镜,具有正光焦度,其物侧面是凸面,其像侧面是凸面; 第五透镜,具有正光焦度,其物侧面是凹面,其像侧面是凸面; 第六透镜,具有负光焦度,其物侧面在近光轴处是凸面,其像侧面在近光轴处是凹面; 其中,所述第二透镜的物侧面曲率半径R3与所述第二透镜的像侧面曲率半径R4满足:0.5 < R3 / R4 < 2;所述第一透镜的物侧面曲率半径R1与所述第一透镜的像侧面曲率半径R2满足:-0.9 < (R1 + R2) / (R1 - R2) < -0.1;所述第一透镜的物侧面通光半口径d1、所述光学镜头的最大视场角所对应的真实像高IH与所述光学镜头的最大视场角FOV满足:1.6 < d1 / (IH / 2) / tan(FOV / 2) < 2.3。 2. The optical lens according to claim 1, characterized in that: 所述光学镜头的光学总长TTL与所述光学镜头的有效焦距f满足:2 < TTL / f < 2.4。 3. The optical lens according to claim 1, characterized in that: 所述光学镜头的最大视场角FOV与所述光学镜头的光圈值Fno满足:27° < FOV / Fno < 35°。 4. The optical lens according to claim 1, characterized in that: 所述光学镜头的有效焦距f与所述第二透镜的焦距f2满足:4.7 < f2 / f < 18.3。 5. The optical lens according to claim 1, characterized in that: 所述光学镜头的有效焦距f与所述第三透镜的焦距f3满足:10 < |f3 / f| < 55;所述第三透镜的物侧面曲率半径R5、所述第三透镜的像侧面曲率半径R6与所述第三透镜的中心厚度CT3满足:0.5 < (R5 - CT3) / R6 < 0.8。 6. The optical lens according to claim 1, characterized in that: 所述第四透镜的物侧面曲率半径R7与所述光学镜头的有效焦距f满足:0.6 < R7 / f < 0.8;所述第四透镜的像侧面曲率半径R8与所述光学镜头的有效焦距f满足:-4.4 < R8 / f < -3.5。 7. The optical lens according to claim 1, characterized in that: 所述第五透镜的物侧面曲率半径R9与所述光学镜头的有效焦距f满足:-5.2 < R9 / f < -2.6;所述第五透镜的像侧面曲率半径R10与所述光学镜头的有效焦距f满足:-2.7 < R10 / f < -1.8。 8. The optical lens according to claim 1, characterized in that: 所述第六透镜的物侧面曲率半径R11与所述光学镜头的有效焦距f满足:14.6 < R11 / f < 42.1;所述第六透镜的像侧面曲率半径R12与所述光学镜头的有效焦距f满足:0.7 < R12 / f < 1。 9. The optical lens according to claim 1, characterized in that: The sagittal height Sag1 of the object-side light-passing semi-aperture of the first lens and the object-side light-passing semi-aperture d1 of the first lens satisfy: -0.2 < Sag1 / d1 < -0.05; the sagittal height Sag11 of the object-side light-passing semi-aperture of the sixth lens and the object-side light-passing semi-aperture d11 of the sixth lens satisfy: -0.4 < Sag11 / d11 < -0.

2.

10. 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: 2.8 < (R9 + R10) / (R9 - R10) < 6.8.

Images