Optical lens

Abstract

The invention discloses an optical lens, which comprises seven lenses and a liquid lens, 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 along an optical axis, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the object side surface and the image side surface of the third lens are convex surfaces; the object side surface and the image side surface of the fourth lens are convex surfaces; a liquid lens with focal power, wherein the liquid lens presents different focal lengths according to different applied voltages; 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 concave surface, and the image side surface of the sixth lens is a convex surface; and the object side surface of the seventh lens is a concave surface, and the image side surface of the seventh lens is a convex surface. The optical lens provided by the invention has the advantages of small total length, high relative illumination, high resolution 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] In recent years, with the development of the automation industry, machine vision has achieved explosive growth, and the application areas of industrial lenses have become increasingly extensive. Because industrial lenses have the characteristics of high resolution, high clarity and good stability, they are widely used in dimensional measurement, defect detection, image acquisition and other fields.

[0003] In order to achieve good image acquisition and analysis functions, this type of industrial lens usually requires high-definition resolution to obtain the image features of the object being photographed, and requires high relative illumination to ensure the uniformity of the illumination of the picture. At the same time, in order for the lens to have good imaging effects at different working distances, the lens needs to capture images at different working distances by focusing. However, the focusing method of traditional lenses is based on mechanical movement. For example, a motor is installed in the lens, and the motor drives the lens or lens group in the lens to move horizontally along the optical axis to change the optical spacing between the lenses or between the lens and the camera chip, thereby compensating for the offset of the lens imaging focus caused by the change in working distance. However, this type of mechanical focus lens has the problems of slow focusing speed, manual focusing and large size, which makes it difficult to meet the use requirements of application scenarios with high real-time requirements. Summary of the invention

[0004] Therefore, the object of the present invention is to provide an optical lens having the characteristic of excellent imaging quality.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions.

[0006] The present invention provides an optical lens, which comprises seven lenses and a liquid lens, and includes the following in order from the object side to the imaging surface along the optical axis:

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

[0008] The second lens has a negative optical power, its object side surface is convex, and its image side surface is concave;

[0009] The third lens has positive refractive power, and both the object side surface and the image side surface are convex;

[0010] The fourth lens has positive refractive power, and both the object side surface and the image side surface are convex;

[0011] A liquid lens having optical power, wherein the liquid lens exhibits different focal lengths according to different applied voltages;

[0012] The fifth lens with a positive optical power, having a convex object side and a convex image side;

[0013] The sixth lens with a negative optical power, having a concave object side and a convex image side;

[0014] The seventh lens with a positive optical power, having a concave object side and a convex image side;

[0015] Wherein, the effective focal length fe of the liquid lens satisfies: fe ∈ (-∞, -264.55] & [294.12, +∞) mm;

[0016] The effective focal length f of the optical lens and the optical total length TTL of the optical lens satisfy: 6.8 < TTL / f < 8.5.

[0017] Further preferably, the optical total length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3 < TTL / IH < 3.8; 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: 2 < IH / f < 2.5.

[0018] Further 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: 0.95 < (IH / 2) / (f × Tan(FOV / 2)) < 1; The maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 32° < FOV / Fno < 40°.

[0019] Further preferably, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.9 < f5 / f < 1.3; The object side curvature radius R9 of the fifth lens and the image side curvature radius R10 of the fifth lens satisfy: -11.4 < R9 / R10 < -5.3.

[0020] Further preferably, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.5 < f6 / f < -1.1; The object side curvature radius R11 of the sixth lens and the image side curvature radius R12 of the sixth lens satisfy: -1 < (R11 - R12) / (R11 + R12) < -0.5.

[0021] Further preferably, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 2.9 < f7 / f < 4.6; The object side curvature radius R13 of the seventh lens and the image side curvature radius R14 of the seventh lens satisfy: 14.7 < R13 / R14 < 22.4.

[0022] Further preferably, the effective focal length f of the optical lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: 4.2 < f56 / f < 8.8.

[0023] Further preferably, the effective focal length f of the optical lens and the curvature radius R11 of the object side surface of the sixth lens satisfy: -1.1 < R11 / f < -0.8; the effective focal length f of the optical lens and the curvature radius R12 of the image side surface of the sixth lens satisfy: -8.9 < R12 / f < -5.2.

[0024] Further preferably, the curvature radius R13 of the object side surface of the seventh lens and the curvature radius R14 of the image side surface of the seventh lens satisfy: 0.6 < (R13 - R14) / (R13 + R14) < 1.

[0025] Further preferably, the clear aperture semi-diameter d11 of the object side surface of the sixth lens and the sagittal height Sag11 of the clear aperture of the object side surface of the sixth lens satisfy: -0.45 < Sag11 / d11 < -0.25; the clear aperture semi-diameter d12 of the image side surface of the sixth lens and the sagittal height Sag12 of the clear aperture of the image side surface of the sixth lens satisfy: -0.1 < Sag12 / d12 < 0.

[0026] The optical lens provided by the present invention adopts a combination of seven pieces of glass and one liquid lens. By reasonably distributing the positions and shapes of the lenses, the optical lens has better imaging capabilities at different object distances and also has good thermal stability. The lens has the advantages of a small overall length, a high relative illumination, a high resolution, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0028] Figure 1 is a schematic structural diagram of the optical lens provided by the first embodiment of the present invention.

[0029] Figure 2 is a field curvature curve diagram of the optical lens provided by the first embodiment of the present invention.

[0030] Figure 3 is an F-Tan(Theta) distortion curve diagram of the optical lens provided by the first embodiment of the present invention.

[0031] Figure 4 is an axial aberration curve diagram of the optical lens provided by the first embodiment of the present invention.

[0032] Figure 5 is a lateral chromatic aberration curve diagram of the optical lens provided by the first embodiment of the present invention.

[0033] Figure 6 This is an MTF curve diagram of the optical lens provided in the first embodiment of the present invention.

[0034] Figure 7 A relative illumination curve diagram of the optical lens provided in the first embodiment of the present invention.

[0035] Figure 8 A schematic structural diagram of an optical lens provided in a second embodiment of the present invention.

[0036] Fig. 9 A field curvature curve diagram of the optical lens provided in the second embodiment of the present invention.

[0037] Fig.10 This is a graph showing the F-Tan (Theta) distortion curve of the optical lens provided in the second embodiment of the present invention.

[0038] Fig.11 This is an axial aberration curve diagram of the optical lens provided in the second embodiment of the present invention.

[0039] Fig.12 A vertical axis chromatic aberration curve diagram of the optical lens provided in the second embodiment of the present invention.

[0040] Fig.13 This is an MTF curve diagram of the optical lens provided in the second embodiment of the present invention.

[0041] Fig.14 A relative illumination curve diagram of the optical lens provided in the second embodiment of the present invention.

[0042] Fig.15 A schematic structural diagram of an optical lens provided in the third embodiment of the present invention.

[0043] Fig.16 A field curvature curve diagram of the optical lens provided in the third embodiment of the present invention.

[0044] Fig.17 This is a F-Tan (Theta) distortion curve of the optical lens provided in the third embodiment of the present invention.

[0045] Fig.18 This is an axial aberration curve diagram of the optical lens provided in the third embodiment of the present invention.

[0046] Fig.19 A vertical axis chromatic aberration curve diagram of the optical lens provided in the third embodiment of the present invention.

[0047] Fig. 20 This is an MTF curve diagram of the optical lens provided in the third embodiment of the present invention.

[0048] Fig.21This is a relative illumination curve diagram of the optical lens provided in the third embodiment of the present invention.

[0049] Fig. 22 This is a schematic diagram of the structure of the liquid lens in the optical lens provided by the present invention. DETAILED DESCRIPTION

[0050] In order to better understand the present invention, a more detailed description will be made of various aspects of the present invention with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of embodiments of the present invention, and are not intended to limit the scope of the present invention 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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 invention, "may" is used to mean "one or more embodiments of the present invention". And, the term "exemplary" is intended to refer to an example or illustration.

[0055] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0056] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0057] The present invention provides an optical lens, which includes: a first lens, a second lens, a third lens, a fourth lens, a liquid lens, a fifth lens, a sixth lens and a seventh lens in sequence along the optical axis from the object side to the imaging surface, and the optical centers of the lenses are located on the same straight line.

[0058] In some embodiments, the first lens may have a negative optical power, and its object side surface is convex, and its image side surface is concave. The second lens may have a negative optical power, and its object side surface is convex, and its image side surface is concave. 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 positive optical power, and its object side surface and image side surface are both convex. The liquid lens may have an optical power, and the liquid lens presents different focal lengths according to the applied voltage, and a stop is provided in the liquid lens. 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 negative optical power, and its object side surface is concave, and its image side surface is convex. The seventh lens may have a positive optical power, and its object side surface is concave, and its image side surface is convex.

[0059] 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.

[0060] In some embodiments, the fifth lens and the sixth 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.

[0061] In some embodiments, the liquid lens includes a first surface, a second surface, a third surface, a fourth surface, a fifth surface, and a sixth surface from the object side to the imaging surface. A stop is provided on the fourth surface to converge the range of light emitted by the front optical system. The first surface, the second surface, the third surface, the fifth surface, and the sixth surface are all planes, and the fourth surface is a curved surface and can have different curvature radii according to different applied driving voltages, thereby enabling the liquid lens to have different optical focal lengths. More specifically, when the optical lens starts working, a certain starting voltage will be applied to the liquid lens according to the current working object distance. At this time, the fourth surface in the liquid lens will present a certain radius of curvature, and the liquid lens has a corresponding focal length. In combination with the other seven lenses, the optical lens can be in the best imaging state; when the working object distance of the optical lens changes within a preset working range, the driving voltage applied to the liquid lens will be automatically adjusted to change the radius of curvature of the fourth surface, and then the focal length of the liquid lens will also change accordingly, that is, according to the different working object distances required by the optical lens, the driving voltage applied to the liquid lens can be automatically adjusted to make the liquid lens have a corresponding focal length, and then the optical lens can have a suitable focal length (the overall focal length of the optical lens is adjusted within a small range), realizing the function of automatic focusing, so that the optical lens has a higher resolution at different working object distances.

[0062] In some embodiments, when the working object distance OBJ of the optical lens satisfies: OBJ ≥ 150 mm, the driving voltage U applied to the liquid lens satisfies: 35 V ≤ U ≤ 45 V, and the effective focal length fe (mm) of the liquid lens satisfies: (-∞, -264.55] & [294.12, +∞). That is, when the optical lens works at a certain range of working object distances, the driving voltage applied to the liquid lens will be automatically adjusted within a certain range, and the automatic adjustment of the driving voltage will cause a corresponding change in the radius of curvature of the fourth surface on the liquid lens, and the radius of curvature of the fourth surface satisfies Re (mm) satisfies: Re∈ (-∞, -14.67] & [16.32, +∞), and the corresponding change in the radius of curvature of the fourth surface will correspondingly change the optical focal length of the liquid lens, so that it has a certain range of positive focal length or negative focal length, thereby causing a small change in the focal length of the optical lens. That is, at different working object distances, by changing the driving voltage on the liquid lens, the curvature radius of the liquid lens can be changed, so that the liquid lens can present different focal lengths, so as to meet the requirement that the optical lens has relatively clear imaging quality at different working object distances, that is, the optical lens can realize the fast autofocus function at different working object distances.

[0063] In some embodiments, the effective focal length f of the optical lens and the overall optical length TTL of the optical lens satisfy: 6.8 < TTL / f < 8.5. By satisfying the above range and reasonably controlling the overall optical length and the effective focal length of the optical lens within a reasonable range, the requirement for miniaturization of the optical lens is met. More specifically, 7.51 < TTL / f < 7.81.

[0064] In some embodiments, the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3 < TTL / IH < 3.8. By satisfying the above range, it is beneficial to achieve the balance between the small volume and the large image plane of the optical lens, so that the lens has a smaller overall length and higher resolution ability at the same time. More specifically, 3.3 < TTL / IH < 3.46.

[0065] 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: 2 < IH / f < 2.5. By satisfying the above range and reasonably controlling the relationship between the image height and the focal length, it helps the optical lens to achieve high pixel characteristics. More specifically, 2.25 < IH / f < 2.28.

[0066] 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: 0.95 < (IH / 2) / (f × Tan(FOV / 2)) < 1. By satisfying the above range, it is beneficial to control the optical lens to have a small distortion. More specifically, 0.95 < (IH / 2) / (f × Tan(FOV / 2)) < 0.97.

[0067] In some embodiments, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 32° < FOV / Fno < 40°. By satisfying the above range and limiting the optical lens to have a suitable field of view angle and aperture value, it can collect light at a large angle and obtain good imaging quality. More specifically, 35.35° < FOV / Fno < 36.74°.

[0068] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.9 < f5 / f < 1.3; the curvature radius R9 of the object side of the fifth lens and the curvature radius R10 of the image side of the fifth lens satisfy: -11.4 < R9 / R10 < -5.3. By satisfying the above range and making the fifth lens have a suitable positive focal length and surface shape, it is beneficial to smoothly transition the light transmitted by the front liquid lens, can effectively reduce the field curvature, and improve the imaging quality of the optical lens. More specifically, 1.04 < f5 / f < 1.15; -10.32 < R9 / R10 < -5.86.

[0069] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.5 < f6 / f < -1.1; 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: -1 < (R11 - R12) / (R11 + R12) < -0.5. Satisfying the above ranges and defining that the fifth lens has an appropriate negative optical power and surface shape can diverge the light rays emerging from the fifth lens, making the light rays in the marginal field of view show an upward trend, which is beneficial for the image points on the imaging surface to be away from the optical axis, so as to be conducive to achieving the effect of matching with a large chip, obtaining a larger picture, and can be cemented with the fifth lens having a positive optical power, which can effectively eliminate aberrations and improve the resolution ability of the optical lens. More specifically, -1.35 < f6 / f < -1.3; -0.8 < (R11 - R12) / (R11 + R12) < -0.72.

[0070] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 2.9 < f7 / f < 4.6; 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: 14.7 < R13 / R14 < 22.4. Satisfying the above ranges, by making the seventh lens have a suitable positive focal length and surface shape, various aberrations of the optical lens can be reduced and the imaging quality can be improved. More specifically, 3.18 < f7 / f < 4.17; 16.36 < R11 / R12 < 20.36.

[0071] In some embodiments, the effective focal length f of the optical lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: 4.2 < f56 / f < 8.8. Satisfying the above ranges can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberrations of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing technology difficulty of the optical lens and improving the assembly yield of the optical lens. More specifically, 4.71 < f56 / f < 8.06.

[0072] In some embodiments, the effective focal length f of the optical lens and the radius of curvature R11 of the object side surface of the sixth lens satisfy: -1.1 < R11 / f < -0.8; the effective focal length f of the optical lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: -8.9 < R12 / f < -5.2. Satisfying the above ranges and reasonably defining the surface shape of the sixth lens is beneficial for increasing the imaging area. More specifically, -0.96 < R11 / f < -0.88; -8.08 < R12 / f < -5.71.

[0073] In some embodiments, 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: 0.6 < (R13 - R14) / (R13 + R14) < 1. Meeting the above range can limit the surface shape of the seventh lens, has the characteristic of correcting field curvature, and is beneficial to the correction of the aberration of the entire optical lens. More specifically, 0.87 < (R13 - R14) / (R13 + R14) < 0.92.

[0074] In some embodiments, the clear aperture semi-diameter d11 of the object side surface of the sixth lens and the sagittal height Sag11 of the clear aperture of the object side surface of the sixth lens satisfy: -0.45 < Sag11 / d11 < -0.25; the clear aperture semi-diameter d12 of the image side surface of the sixth lens and the sagittal height Sag12 of the clear aperture of the image side surface of the sixth lens satisfy: -0.1 < Sag12 / d12 < 0. Meeting the above range helps to control the trend of the light rays in the edge field of view and highlight the detailed information of the central field of view of the optical lens. More specifically, -0.39 < Sag11 / d11 < -0.31; -0.06 < Sag12 / d12 < -0.03.

[0075] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.85 < BFL / f < 1.05. Meeting the above range defines that the optical lens has a suitable back focus, which is convenient for reasonably arranging the positions of each lens and reduces the processing and assembly difficulty at the same time. More specifically, 0.92 < BFL / f < 0.95.

[0076] In some embodiments, the maximum field of view FOV of the optical lens, the effective focal length f of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 43.72° < f × FOV / IH < 47°. Meeting the above range can balance the requirements of large-range detection and high-quality imaging and improve the adaptability of the optical lens. More specifically, 43.71° < f × FOV / IH < 43.83°.

[0077] In some embodiments, the sum ∑CT of the central thicknesses of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens and the total optical length TTL of the optical lens satisfy: 0.35 < ∑CT / TTL < 0.5. Meeting the above range can achieve high-pixel characteristics and improve the imaging quality of the optical lens by reasonably defining the central thicknesses of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens and the total optical length of the optical lens. More specifically, 0.41 < ∑CT / TTL < 0.44.

[0078] In some embodiments, the sum of the central thicknesses ∑CT of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens and the effective focal length f of the optical lens satisfy: 2.8 < ∑CT / f < 3.7. Meeting the above range can effectively correct the field curvature and distortion of the optical lens and improve the imaging quality of the optical lens. More specifically, 3.16 < ∑CT / f < 3.34.

[0079] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -3.3 < f1 / f < -1.9. Meeting the above range makes the first lens have a negative optical power and can diverge the light passing through it, which is beneficial to achieving a small front aperture. More specifically, -3.01 < f1 / f < -2.15.

[0080] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.3 < f2 / f < -2. Meeting the above range makes the second lens have a negative optical power and can diverge the light. At the same field of view angle, it further diverges the light exiting from the image side of the first lens, can disperse the central light and the marginal light of each field of view, and enables the rear optical system to have a larger light receiving surface to receive the light exiting from the image side of the second lens, achieving a larger light entrance amount and being beneficial to increasing the relative illuminance. More specifically, -2.98 < f2 / f < -2.27.

[0081] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 3.1 < f3 / f < 8.1. Meeting the above range limits the third lens to have an appropriate positive optical power, which is beneficial to the convergence of light, enables the light entering the system from the front to smoothly enter the rear optical system, makes the light trend smoother, optimizes the aberration, and improves the resolution. More specifically, 3.45 < f3 / f < 7.37.

[0082] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 2.2 < f4 / f < 3.5. Meeting the above range is beneficial to the convergence of light, is beneficial to making the light enter the rear lens smoothly, and further can reduce the field curvature and correct the off-axis point aberration of the optical lens. More specifically, 2.42 < f4 / f < 3.15.

[0083] In some embodiments, the combined focal length f56 of the fifth lens and the sixth lens and the combined focal length f567 of the fifth lens, the sixth lens, and the seventh lens satisfy: 1.7 < f56 / f567 < 3.5. Meeting the above range and reasonably distributing the proportion of the focal length of the cemented lens group in the focal length of the rear lens group 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.

[0084] In some embodiments, the effective focal length f of the optical lens and the object-side curvature radius R5 of the third lens satisfy: 5 < R5 / f < 14.5; the effective focal length f of the optical lens and the image-side curvature radius R6 of the third lens satisfy: -14.5 < R6 / f < -5. Meeting the above range, the object side and the image side of the third lens are symmetric surface types, which is beneficial to the correction of various aberrations of the optical lens and improves the imaging quality of the optical lens. More specifically, 5.51 < R5 / f < 13.15; -13.15 < R6 / f < -5.51.

[0085] In some embodiments, the effective focal length f of the optical lens and the object-side curvature radius R13 of the seventh lens satisfy: -61 < R13 / f < -37; the effective focal length f of the optical lens and the image-side curvature radius R14 of the seventh lens satisfy: -3.1 < R14 / f < -1.9. Meeting the above range enables the light 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 the light energy loss caused by the excessive main ray angle of the large field of view light when reaching the imaging surface, is conducive to improving the illuminance of the edge field of view, and is beneficial to achieving a short overall optical length. More specifically, -55.66 < R13 / f < -41.98; -2.78 < R14 / f < -2.11.

[0086] In some embodiments, the image-side curvature radius R6 of the third lens and the object-side curvature radius R7 of the fourth lens satisfy: -4.7 < R6 / R7 < -1.7. Meeting the above range can reduce the light deflection angle, make the light trend smoother; at the same time, it can correct coma and field curvature, improve the flatness of imaging, and improve the imaging quality of the optical lens. More specifically, -4.27 < R6 / R7 < -1.86.

[0087] In some embodiments, the distance CT67 between the sixth lens and the seventh lens on the optical axis and the central thickness CT7 of the seventh lens satisfy: 2.9 < CT67 / CT7 < 6. Meeting the above range, by reasonably limiting the air gap between the sixth lens and the seventh lens on the optical axis and the central thickness of the seventh lens, the reasonable arrangement of each lens in the optical lens can be maintained, and the structural stability of the optical lens can be improved. More specifically, 3.21 < CT67 / CT7 < 5.48.

[0088] In some embodiments, the optical lens satisfies the following conditional expressions: 3 mm < f < 3.6 mm; 90° < FOV < 110°; 1.1 mm < EPD < 1.3 mm; 22.4 mm < TTL < 28.5 mm; 2.5 < Fno < 3; 7 mm < IH < 8 mm; 14° < CRA < 16°; 2.8 mm < BFL < 3.4 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the principal ray incident angle at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. Meeting the above ranges, the optical lens has at least one or more advantages such as a small total length, a relatively large field of view angle, a large image plane, and high resolution. Preferably, the optical lens satisfies the following conditional expressions: 3.29 mm < f < 3.33 mm; 98° < FOV < 100°; 1.17 mm < EPD < 1.21 mm; 24.79 mm < TTL < 25.91 mm; 2.7 < Fno < 2.81; 7.4 mm < IH < 7.6 mm; 14.69° < CRA < 14.81°; 3 mm < BFL < 3.2 mm.

[0089] 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 can be made of all-glass lenses or a combination of glass and plastic lenses, and both can achieve good imaging effects. In this application, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are all made of glass lenses.

[0090] 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 can be spherical lenses or aspherical lenses. Compared with the aspherical structure, the spherical structure can reduce the processing difficulty and production cost. 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 all spherical lenses.

[0091] In various embodiments 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:

[0092]

[0093] where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the conic coefficient, and B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients, respectively.

[0094] 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.

[0095] First embodiment

[0096] See also Figure 1 , shown is a schematic diagram of the structure of an optical lens 100 provided in the first embodiment of the present invention, which comprises seven lenses and a liquid lens. The optical lens 100 comprises, in sequence from the object side to the imaging surface S24 along the optical axis: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a liquid lens E1, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1 and a protective glass G2, and the optical centers of the lenses are located on the same straight line.

[0097] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0098] The second lens L2 has negative refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave;

[0099] The third lens L3 has positive refractive power, and its object-side surface S5 and image-side surface S6 are both convex;

[0100] The fourth lens L4 has positive refractive power, and its object-side surface S7 and image-side surface S8 are both convex surfaces;

[0101] The fifth lens L5 has positive refractive power, and its object-side surface S15 and image-side surface S16 are both convex surfaces;

[0102] The sixth lens L6 has negative refractive power, its object-side surface S16 is concave, and its image-side surface S17 is convex;

[0103] The fifth lens L5 and the sixth lens L6 form a cemented lens group with positive refractive power, that is, the cemented surface between the image side surface of the fifth lens L5 and the object side surface of the fifth lens L5 is S16;

[0104] The seventh lens L7 has positive refractive power, its object-side surface S18 is concave, and its image-side surface S19 is convex;

[0105] The object side surface S20 and the image side surface S21 of the filter G1 are both planes;

[0106] The object-side surface S22 and the image-side surface S23 of the protective glass G2 are both flat surfaces.

[0107] 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.

[0108] Also, see Fig. 22 , the liquid lens E1 includes a first surface S9, a second surface S10, a third surface S11, a fourth surface S12, a fifth surface S13 and a sixth lens S14 from the object side to the imaging surface. Among them, the aperture ST is arranged at the fourth surface S12, the first surface S9, the second surface S10, the fourth surface S12, the fifth surface S13 and the sixth lens S14 are all planes, the third surface S11 is a curved surface and the third surface S11 can have different radii of curvature according to different applied driving voltages, so that the liquid lens E1 can have different optical focal lengths. For example, when the working object distance OBJ of the optical lens satisfies: OBJ ≥ 150 mm, the driving voltage U applied to the liquid lens satisfies: 38.05 V ≤ U ≤ 39.95 V, and the effective focal length fe (mm) of the liquid lens satisfies: fe∈[-2738.54, -573.54].

[0109] The relevant parameters of each lens in the optical lens 100 provided in this embodiment are shown in Table 1-1.

[0110] Table 1-1

[0111]

[0112]

[0113] In this embodiment, when the working object distance OBJ of the optical lens satisfies: OBJ ≥ 150 mm, the driving voltage U applied to the liquid lens satisfies: 38.05 V ≤ U ≤ 39.95 V, the radius of curvature Re of the third surface satisfies: Re ∈ [-155.69, -32.61] mm, the effective focal length fe of the liquid lens satisfies: fe ∈ [-2738.54, -573.54] mm, and the effective focal length f of the optical lens satisfies: 3.29 mm ≤ f ≤ 3.31 mm. More specifically, when the optical lens is at the optimal working object distance of 300 mm, the voltage applied to the liquid lens is 39 V (this voltage is the starting voltage), the radius of curvature of the third surface of the liquid lens is -53.68 mm, and the effective focal length of the liquid lens is -944.17 mm, and the effective focal length of the optical lens is 3.3 mm. The relevant parameters of the optical lens 100 provided in this embodiment at the optimal working object distance, the minimum working object distance, and the maximum working object distance are shown in Table 1-2.

[0114] Table 1-2

[0115] Optimal working distance Minimum working distance Maximum working distance OBJ(mm) 300 150 endless f(mm) 3.30 3.29 3.31 U(V) 39.00 39.95 38.05 fe(mm) -944.17 -2738.54 -573.54 Re(mm) -53.68 -155.69 -32.61

[0116] Figure 2 The field curvature curve of the optical lens 100 in this embodiment 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 ±0.05mm, indicating that the optical lens can correct the field curvature well.

[0117] Figure 3 The F-Tan (Theta) distortion curve of the optical lens 100 in this embodiment is shown, which represents the distortion of different field angles on the imaging plane, with the horizontal axis representing the distortion value (unit: %) and the vertical axis representing the half field angle (unit: °). It can be seen from the figure that the distortion value is controlled within ±4%, indicating that the optical lens can correct the distortion well.

[0118] Figure 4 The axial aberration curve of the optical lens 100 in this embodiment 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 ±0.02mm, indicating that the optical lens can better correct the axial aberration.

[0119] Figure 5 The vertical axis chromatic aberration curve of the optical lens 100 in this embodiment 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 axis chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±5 μm, indicating that the optical lens can correct chromatic aberration well.

[0120] Figure 6 The modulation transfer function (MTF) curve of the optical lens 100 in this embodiment 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 0.45 within the full half image height, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency conditions.

[0121] Figure 7The relative illumination curve of the optical lens 100 in this embodiment is shown, which represents the relative illumination values ​​of different image heights on the imaging surface, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination value (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 60% at the maximum half field angle, indicating that the optical lens has good relative illumination.

[0122] Second embodiment

[0123] See also Figure 8 , shown is a schematic diagram of the structure of an optical lens 200 provided in the second embodiment of the present invention. The structure of the optical lens 200 is substantially the same as that of the optical lens 100 in the first embodiment, and the main difference lies in that the parameters of the liquid lens are different, and the curvature radius, thickness, and spacing between lenses of each lens are different.

[0124] The relevant parameters of each lens in the optical lens 200 provided in this embodiment are shown in Table 2-1.

[0125] Table 2-1

[0126]

[0127]

[0128] In this embodiment, when the working object distance OBJ of the optical lens satisfies: OBJ ≥ 150 mm, the driving voltage U applied to the liquid lens satisfies: 39.47 V ≤ U ≤ 41.5 V, the radius of curvature Re of the third surface satisfies: Re ∈ (-∞, -79.32] & [72.18, +∞) mm, the effective focal length fe of the liquid lens satisfies: fe ∈ (-∞, -1395.28] & [1269.66, +∞) mm, and the effective focal length f of the optical lens satisfies: 3.3 mm ≤ f ≤ 3.32 mm. More specifically, when the optical lens is at the optimal working object distance of 300 mm, the voltage applied to the liquid lens is 40.57 V (this voltage is the starting voltage), the radius of curvature of the third surface of the liquid lens is 595.99 mm, and the effective focal length of the liquid lens is 10483.45 mm, and the effective focal length of the optical lens is 3.31 mm. The relevant parameters of the optical lens 200 provided in this embodiment at the optimal working object distance, the minimum working object distance, and the maximum working object distance are shown in Table 2-2.

[0129] Table 2-2

[0130] Optimal working distance Minimum working distance Maximum working distance OBJ(mm) 300 150 endless f(mm) 3.31 3.30 3.32 U(V) 40.57 41.50 39.47 fe(mm) 10483.45 1269.66 -1395.28 Re(mm) 595.99 72.18 -79.32

[0131] Figures 9 to 14The field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical chromatic aberration curve, MTF curve and relative illumination curve of the optical lens 200 in this embodiment are shown.

[0132] from Fig. 9 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.04mm, indicating that the optical lens can correct the field curvature well;

[0133] from Fig.10 It can be seen that the distortion value is controlled within ±4%, indicating that the optical lens can correct the distortion well;

[0134] from Fig.11 It can be seen that the offset of axial aberration is controlled within ±0.02mm, indicating that the optical lens can correct axial aberration well;

[0135] from Fig.12 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±5μm, indicating that the optical lens can correct chromatic aberration well;

[0136] from Fig.13 It can be seen that the MTF value of this embodiment is above 0.5 in the whole half-image height, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions;

[0137] from Fig.14 It can be seen that at the maximum half field of view angle, the relative illumination value of the optical lens is still 55% greater, indicating that the optical lens has good relative illumination.

[0138] Third embodiment

[0139] See also Fig.15 , shown is a schematic diagram of the structure of an optical lens 300 provided in the third embodiment of the present invention. The structure of the optical lens 300 is substantially the same as that of the optical lens 100 in the first embodiment, and the main difference lies in: the parameters of the liquid lens are different, and the curvature radius, thickness, spacing between lenses, and materials of each lens are different.

[0140] The relevant parameters of each lens in the optical lens 300 provided in this embodiment are shown in Table 3-1.

[0141] Table 3-1

[0142]

[0143]

[0144] In this embodiment, when the working object distance OBJ of the optical lens satisfies: OBJ ≥ 150 mm, the driving voltage U applied to the liquid lens satisfies: 38.97 V ≤ U ≤ 41.11 V, the radius of curvature Re of the third surface satisfies: Re ∈ (-∞, -52.59] & [114.02, +∞) mm, the effective focal length fe of the liquid lens satisfies: fe ∈ (-∞, -925.14] & [2005.55, +∞) mm, and the effective focal length f of the optical lens satisfies: 3.31 mm ≤ f ≤ 3.33 mm. More specifically, when the optical lens is at the optimal working object distance of 300 mm, the voltage applied to the liquid lens is 40 V (this voltage is the starting voltage), the radius of curvature of the third surface of the liquid lens is -173.13 mm, and the effective focal length of the liquid lens is -3045.36 mm, and the effective focal length of the optical lens is 3.32 mm. The relevant parameters of the optical lens 300 provided in this embodiment at the optimal working object distance, the minimum working object distance, and the maximum working object distance are shown in Table 3-2.

[0145] Table 3-2

[0146] Optimal working distance Minimum working distance Maximum working distance OBJ(mm) 300 150 endless f(mm) 3.32 3.31 3.33 U(V) 40.00 41.11 38.97 fe(mm) -3045.36 2005.55 -925.14 Re(mm) -173.13 114.02 -52.59

[0147] Figures 16 to 21 The field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical chromatic aberration curve, MTF curve and relative illumination curve of the optical lens 300 in this embodiment are shown.

[0148] from Fig.16 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.04mm, indicating that the optical lens can correct the field curvature well;

[0149] from Fig.17 It can be seen that the distortion value is controlled within ±4%, indicating that the optical lens can correct the distortion well;

[0150] from Fig.18 It can be seen that the offset of axial aberration is controlled within ±0.02mm, indicating that the optical lens can correct axial aberration well;

[0151] from Fig.19 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±4μm, indicating that the optical lens can correct chromatic aberration well;

[0152] from Fig. 20 It can be seen that the MTF value of this embodiment is above 0.6 in the whole half image height, and has good imaging quality and good detail resolution capability in both low frequency and high frequency conditions;

[0153] from Fig.21 It can be seen that at the maximum half field of view angle, the relative illumination value of the optical lens is still greater than 60%, indicating that the optical lens has good relative illumination.

[0154] Please refer to Table 4, which shows the optical characteristics of the optical lenses provided by the above three embodiments at the optimal working object distance, including the working object distance OBJ, effective focal length f, total optical length TTL, maximum field of view FOV, real image height IH corresponding to the maximum field of view, aperture value Fno, driving voltage U of the liquid lens, and effective focal length fe of the liquid lens, as well as the relevant numerical values ​​corresponding to each of the above conditional expressions.

[0155] Table 4

[0156]

[0157]

[0158] In summary, the optical lens provided by the present invention has at least the following advantages:

[0159] The optical lens provided by the present invention adopts a combination of seven lenses and one liquid lens. By reasonably allocating the focal length relationship between the liquid lens and each lens, the optical lens has better imaging ability at different object distances and also has good thermal stability. At the same time, by reasonably configuring the thickness of each lens, the distance between each lens and the surface shape of each lens, the optical lens has the advantages of short total length, high relative illumination, high resolution and the like.

[0160] 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.

[0161] The above-described 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 present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. An optical lens, comprising seven lenses and one liquid lens, characterized in that: It sequentially includes from the object side to the imaging plane along the optical axis: A first lens with negative optical power, whose object side is convex and whose image side is concave; A second lens with negative optical power, whose object side is convex and whose image side is concave; A third lens with positive optical power, whose object side and image side are both convex; A fourth lens with positive optical power, whose object side and image side are both convex; A liquid lens with optical power, and the liquid lens presents different focal lengths according to different applied voltages; A fifth lens with positive optical power, whose object side and image side are both convex; A sixth lens with negative optical power, whose object side is concave and whose image side is convex; A seventh lens with positive optical power, whose object side is concave and whose image side is convex; Wherein, the effective focal length fe of the liquid lens satisfies: fe ∈ (-∞, -264.55] & [294.12, +∞) mm; The effective focal length f of the optical lens and the overall optical length TTL of the optical lens satisfy: 6.8 < TTL / f < 8.

5.

2. The optical lens according to claim 1, characterized in that: The overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3 < TTL / IH < 3.8; 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: 2 < IH / f < 2.

5.

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, the effective focal length f of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 0.95 < (IH / 2) / (f × Tan(FOV / 2)) < 1; The maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 32° < FOV / Fno < 40°.

4. The optical lens according to claim 1, characterized in that: The focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.9 < f5 / f < 1.3; The curvature radius R9 of the object side of the fifth lens and the curvature radius R10 of the image side of the fifth lens satisfy: -11.4 < R9 / R10 < -5.

3.

5. The optical lens according to claim 1, characterized in that: The focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.5 < f6 / f < -1.1; 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: -1 < (R11 - R12) / (R11 + R12) < -0.

5.

6. The optical lens according to claim 1, characterized in that: The focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 2.9 < f7 / f < 4.6; The curvature radius R13 of the object side of the seventh lens and the curvature radius R14 of the image side of the seventh lens satisfy: 14.7 < R13 / R14 < 22.

4.

7. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: 4.2 < f56 / f < 8.

8.

8. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the curvature radius R11 of the object side surface of the sixth lens satisfy: -1.1 < R11 / f < -0.8; the effective focal length f of the optical lens and the curvature radius R12 of the image side surface of the sixth lens satisfy: -8.9 < R12 / f < -5.

2.

9. The optical lens according to claim 1, characterized in that: The curvature radius R13 of the object side surface of the seventh lens and the curvature radius R14 of the image side surface of the seventh lens satisfy: 0.6 < (R13 - R14) / (R13 + R14) < 1.

10. The optical lens according to claim 1, characterized in that: The clear aperture semi-diameter d11 of the object side surface of the sixth lens and the sagittal height Sag11 of the clear aperture of the object side surface of the sixth lens satisfy: -0.45 < Sag11 / d11 < -0.25; the clear aperture semi-diameter d12 of the image side surface of the sixth lens and the sagittal height Sag12 of the clear aperture of the image side surface of the sixth lens satisfy: -0.1 < Sag12 / d12 < 0.

Images