Optical lens

Abstract

This invention provides an optical lens comprising seven lenses of optical power, arranged sequentially along the optical axis from the object side to the image plane: a first lens with negative optical power, both its object side and image side being concave; a second lens with negative optical power; a third lens with positive optical power, both its object side and image side being convex; a fourth lens with negative optical power, its object side being concave; a fifth lens with positive optical power, both its object side and image side being convex; a sixth lens with negative optical power, its object side being concave; and a seventh lens with positive optical power, both its object side and image side being convex. The optical lens provided by this invention, through a specific combination of surface shapes and a reasonable distribution of optical power, reduces aberrations and improves the image quality of the lens, giving it one or more advantages such as a large image plane, a wide field of view, miniaturization, low CRA (Cost Averaging Reduction), and high collimation performance.

Description

Technical Field , , , , ,

[0006] ,

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

[0002] Nowadays, lidar is widely used in detecting the three-dimensional coordinates of objects and ranging. The lidar includes a controller, a light source and a receiving device. The controller controls the light source to emit a light beam. After the light beam encounters a target object, it undergoes diffuse reflection. The receiving device is used to receive the reflected light beam, and relevant information of the target object, such as parameters like target distance, azimuth, height, speed, attitude, and even shape, is determined based on the information of the emitted light beam and the reflected light beam. Lidar is widely used in autonomous driving vehicles, drones, autonomous robots, weeders, etc.

[0003] As a key component of lidar, the optical lens can receive and process the reflected light. With the continuous increase in the performance requirements of lidar in application scenarios, the parameters of the optical lens need to develop towards large aperture, large field of view, and small aberration to meet the growing demand for high-precision and wide-coverage detection. The optical lenses of current lidar have the problem of low imaging quality and cannot meet the market demand. Summary of the Invention

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

[0005] The present invention provides an optical lens, and the number of lenses with optical power is seven. Along the optical axis from the object side to the imaging surface, it successively includes: A first lens with negative optical power, whose object side is concave and image side is concave; A second lens with negative optical power; A third lens with positive optical power, whose object side is convex and image side is convex; A fourth lens with negative optical power, whose object side is concave; A fifth lens with positive optical power, whose object side is convex and image side is convex; A sixth lens with negative optical power, whose object side is concave; A seventh lens with positive optical power, whose object side is convex and image side is convex; Wherein, 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: 1.6 < TTL / IH < 2.2; the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 1 < f4567 / f < 2.5. [[ID=​Further preferably, the optical lens satisfies one or more of the following conditional expressions: the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.6 < TTL / f < 3.3; the true image height IH corresponding to the maximum field angle of the optical lens and the radian value θ of the maximum half-field angle of the optical lens satisfy: 28mm < (IH / 2) / θ < 35mm.

[0007] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 31° < FOV / Fno < 43°; the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.7 < IH / EPD < 5.4.

[0008] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.3 < IH / f < 1.8; the total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.05 < 1°×TTL / (IH / 2) / (FOV / 2) < 0.09.

[0009] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the effective focal length f of the optical lens, the maximum field angle FOV of the optical lens, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 63° < f×FOV / IH < 78°; the half-aperture d1 of the object side of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.35 < d1 / (IH / 2) / tan(FOV / 2) < 0.8.

[0010] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the true image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half-field angle of the optical lens satisfy: 0.75 < (IH / 2) / (f×θ) < 0.9; the half-aperture d1 of the object side of the first lens and the half-aperture d14 of the image side of the seventh lens satisfy: 0.4 < d1 / d14 < 0.9.

[0011] Further preferably, the optical lens satisfies one or more of the following conditional expressions: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -3.4 < f1 / f < -1; The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.6 < f3 / f < 1.3; The focal length f1 of the first lens and the focal length f3 of the third lens satisfy: -5 < f1 / f3 < -1.4.

[0012] Further preferably, the optical lens satisfies one or more of the following conditional expressions: The focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -22 < f2 / f < -0.9; The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -29 < f4 / f < -1; The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.7 < f5 / f < 1.3; The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -3.3 < f6 / f < -1.1; The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.4 < f7 / f < 2; The focal length f1 of the first lens and the combined focal length f123 of the first lens, the second lens and the third lens satisfy: -1.8 < f1 / f123 < -0.15; The focal length f3 of the third lens and the combined focal length f123 of the first lens, the second lens and the third lens satisfy: 0.05 < f3 / f123 < 0.9.

[0013] Further preferably, the optical lens satisfies one or more of the following conditional expressions: 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: -2.7 < R1 / R2 < -0.9; 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 < (R1 + R2) / (R1 - R2) < 0.5; The radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -0.7 < R5 / R6 < -0.3; The radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -0.5 < (R5 + R6) / (R5 - R6) < -0.2.

[0014] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.77 < TTL / IH < 2.05; the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens and the effective focal length f of the optical lens satisfy: 1.22 < f4567 / f < 2.26; the object-side curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: -4.5 < R1 / f < -1.7; the image-side curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: 0.7 < R2 / f < 2.9; the object-side curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: 0.8 < R5 / f < 1.6; the image-side curvature radius R6 of the third lens and the effective focal length f of the optical lens satisfy: -2.9 < R6 / f < -1.4.

[0015] The optical lens provided by the present invention adopts seven lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it can improve the receiving quality of the lens, reduce aberration, improve the imaging quality of the lens, and enable the lens to have one or more advantages such as a large image plane, a large field angle, miniaturization, a small CRA, and high collimation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, where: Figure 1 It is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0017] Figure 2 It is a graph of F-Tan(Theta) distortion of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 3 It is a MTF graph of the optical lens in Embodiment 1 of the present invention.

[0019] Figure 4 It is a relative illumination graph of the optical lens in Embodiment 1 of the present invention.

[0020] Figure 5 It is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0021] Figure 6 It is a graph of F-Tan(Theta) distortion of the optical lens in Embodiment 2 of the present invention.

[0022] Figure 7 It is a MTF graph of the optical lens in Embodiment 2 of the present invention.

[0023] Figure 8 This is a relative illumination curve of the optical lens in Embodiment 2 of the present invention.

[0024] Figure 9 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0025] Figure 10 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0026] Figure 11 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0027] Figure 12 This is a relative illumination curve of the optical lens in Embodiment 3 of the present invention.

[0028] Figure 13 This is a schematic diagram of the optical lens structure in Embodiment 4 of the present invention.

[0029] Figure 14 This is the F-Tan (Theta) distortion curve of the optical lens in Embodiment 4 of the present invention.

[0030] Figure 15 This is the MTF curve of the optical lens in Embodiment 4 of the present invention.

[0031] Figure 16 This is a relative illumination curve of the optical lens in Embodiment 4 of the present invention.

[0032] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0033] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of this application and are not intended to limit the scope of this 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.

[0034] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0035] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0036] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity 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 location of the concaveness 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 subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0037] It should also be understood that the terms "comprising," "including," "having," "containing," 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. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0038] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] The optical lens provided in this embodiment of the invention can be used as a receiving lens for lidar, transmitting light reflected from the surface of an object to the imaging plane. The optical lens of this invention has seven lenses with optical power, sequentially comprising, along the optical axis from the object side to the imaging plane: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens.

[0041] In some embodiments, the first lens may have a negative optical power, with its object side being concave and its image side being concave. The second lens may have a negative optical power, and its object side may be concave or convex, and its image side may be concave or convex. The third lens may have a positive optical power, with its object side being convex and its image side being convex. The fourth lens may have a negative optical power, with its object side being concave, and its image side may be concave or convex. The fifth lens may have a positive optical power, with its object side being convex and its image side being convex. The sixth lens may have a negative optical power, with its object side being concave, and its image side may be concave or convex. The seventh lens may have a positive optical power, with its object side being convex and its image side being convex.

[0042] In some embodiments, the optical lens may further include an aperture, and the aperture may be located between the third lens and the fourth lens. It can be understood that the aperture is used to limit the amount of incident light to change the brightness of the image. When the aperture is located between the third lens and the fourth lens, it is convenient for correcting the aperture aberration.

[0043] In some embodiments, the optical lens may further include a filter, and the filter is disposed between the seventh lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0044] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.6 < TTL / IH < 2.2; the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.6 < TTL / f < 3.3. Meeting the above ranges, by reasonably controlling the total length, focal length, and image height of the optical lens, it helps the optical lens to achieve the balance of the total length and volume, and is beneficial to improving the structural stability of the optical lens. More specifically, 1.77 < TTL / IH < 2.05; 2.84 < TTL / f < 3.01.

[0045] In some embodiments, the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens and the effective focal length f of the optical lens satisfy: 1 < f4567 / f < 2.5. Meeting the above ranges can make the overall rear end of the optical lens have a strong positive optical power, effectively transmit more light beams to the imaging surface, and can reduce the deviation of the incident angle and the exit angle of light rays in different fields of view. More specifically, 1.22 < f4567 / f < 2.26.

[0046] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the radian value θ of the maximum half-field angle of the optical lens satisfy: 28mm < (IH / 2) / θ < 35mm. Meeting the above ranges realizes the large image plane characteristic and improves the imaging quality of the optical system. More specifically, 31.24mm < (IH / 2) / θ < 32.55mm.

[0047] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 31° < FOV / Fno < 43°. Meeting the above conditions is conducive to expanding the field of view of the lens and increasing the aperture of the lens, achieving the characteristics of a large aperture. More specifically, 34.45° < FOV / Fno < 39.3°.

[0048] In some embodiments, the true image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.7 < IH / EPD < 5.4. Meeting the above conditions makes the field of view and light flux balanced, improves the imaging quality of the lens, and can achieve high-quality collimation performance. More specifically, 4.09 < IH / EPD < 4.94.

[0049] In some embodiments, the true image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 1.3 < IH / f < 1.8. Meeting the above range can reasonably control the image height and focal length of the optical lens, provide a balance between the image height and focal length for the optical lens, and help improve the imaging quality. More specifically, 1.46 < IH / f < 1.61.

[0050] In some embodiments, the total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view of the optical lens, and the maximum field of view FOV of the optical lens satisfy: 0.05 < 1° × TTL / (IH / 2) / (FOV / 2) < 0.09. Meeting the above range helps to control the structural balance of the total optical length, field of view angle, and image height of the optical lens, and makes the structure of the optical lens more stable on the premise of meeting the design requirements.

[0051] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 63° < f × FOV / IH < 78°. Meeting the above range is conducive to achieving the balance between the 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, 67.99° < f × FOV / IH < 70.97°.

[0052] In some embodiments, the clear aperture radius d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.35 < d1 / (IH / 2) / tan(FOV / 2) < 0.8. Meeting the above range can reasonably control the front aperture while meeting the requirements of the optical lens having a large field angle and a large image height, which is beneficial to the miniaturization of the optical lens. More specifically, 0.39 < d1 / (IH / 2) / tan(FOV / 2) < 0.75.

[0053] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half field angle of the optical lens satisfy: 0.75 < (IH / 2) / (f×θ) < 0.9. Meeting the above range helps to keep the distortion of the optical lens within a reasonable range, making the picture ratios of each field in the final imaging plane more harmonious and improving the imaging quality. More specifically, 0.8 < (IH / 2) / (f×θ) < 0.85.

[0054] In some embodiments, the clear aperture radius d1 of the object side surface of the first lens and the clear aperture radius d14 of the image side surface of the seventh lens satisfy: 0.4 < d1 / d14 < 0.9. Meeting the above conditions, by reasonably setting the ratio of the apertures of the first and last lenses, the lens can have a smaller head size while having a larger imaging surface, better meeting the balance between miniaturization and high pixels. More specifically, 0.46 < d1 / d14 < 0.85.

[0055] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -3.4 < f1 / f < -1. Meeting the above range can make the first lens have a strong negative optical power, capture light rays with a large field angle, which is beneficial to the optical lens having the characteristic of a large field angle. More specifically, -3.15 < f1 / f < -1.09.

[0056] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.6 < f3 / f < 1.3. The third lens is a positive lens, which transmits the light beam to the final imaging lens group, compensates for the aberration with the front and rear lenses, thereby achieving high imaging quality of the lens and high-quality collimation performance. More specifically, 0.66 < f3 / f < 1.21.

[0057] In some embodiments, the focal length f1 of the first lens and the focal length f3 of the third lens satisfy: -5 < f1 / f3 < -1.4. Meeting the above range can enable the large-field beam to quickly collect and adjust the optical path at the front end of the lens, thereby ensuring a smaller aperture at the front end and achieving the characteristics of a large field angle and small volume of the lens. More specifically, -4.71 < f1 / f3 < -1.59.

[0058] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -22 < f2 / f < -0.9. Meeting the above range can enable the second lens to have an appropriate negative optical power, further expand the field angle of the optical lens, and evenly share the negative optical power at the front end of the optical lens. More specifically, -19.96 < f2 / f < -0.95.

[0059] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -29 < f4 / f < -1. Meeting the above range helps the fourth lens to have an appropriate negative optical power and can appropriately reduce spherical aberration and coma. More specifically, -26.84 < f4 / f < -1.13.

[0060] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.7 < f5 / f < 1.3. Meeting the above range helps the fifth lens to have an appropriate positive optical power and balance the field curvature and astigmatism of the optical lens. More specifically, 0.81 < f5 / f < 1.24.

[0061] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -3.3 < f6 / f < -1.1. Meeting the above range helps the sixth lens to have an appropriate negative optical power, enables reasonable control of the smooth light trend at the rear end of the optical lens, and reduces aberration. More specifically, -3.05 < f6 / f < -1.21.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.4 < f7 / f < 2. Meeting the above range can enable the seventh lens to have an appropriate positive optical power, helps to reasonably control the angle of light entering the rear-end chip, and reduces the eccentricity sensitivity of the chip. More specifically, 1.55 < f7 / f < 1.88.

[0063] In some embodiments, the focal length f1 of the first lens and the combined focal length f123 of the first, second, and third lenses satisfy: -1.8 < f1 / f123 < -0.15; the focal length f3 of the third lens and the combined focal length f123 of the first, second, and third lenses satisfy: 0.05 < f3 / f123 < 0.9; the combined focal length f123 of the first, second, and third lenses and the effective focal length f of the optical lens satisfy: 0.9 < f123 / f < 15. Meeting the above ranges enables the first lens, the third lens, and the overall front end of the optical lens to have appropriate optical powers, and allows large-angle light entering the lens to be fully transmitted to the rear optical system, obtaining a larger field of view and higher relative illumination. More specifically, -1.67 < f1 / f123 < -0.19; 0.08 < f3 / fk123 < 0.84; 0.95 < f123 / f < 13.42.

[0064] In some embodiments, 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: -2.7 < R1 / R2 < -0.9; 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 < (R1 + R2) / (R1 - R2) < 0.5; the curvature radius R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -4.5 < R1 / f < -1.7; the curvature radius R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: 0.7 < R2 / f < 2.9. Meeting the above ranges can reasonably set the surface shape of the first lens, enhance the light-gathering ability of the first lens, and thus achieve an ultra-large field of view angle. More specifically, -2.43 < R1 / R2 < -1.03; 0.01 < (R1 + R2) / (R1 - R2) < 0.43; -4.07 < R1 / f < -1.9; 0.78 < R2 / f < 2.66.

[0065] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -0.7 < R5 / R6 < -0.3; the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -0.5 < (R5 + R6) / (R5 - R6) < -0.2; the radius of curvature R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy: 0.8 < R5 / f < 1.6; the radius of curvature R6 of the image side surface of the third lens and the effective focal length f of the optical lens satisfy: -2.9 < R6 / f < -1.4. Satisfying the above ranges, the third lens has a suitable surface shape, which helps to control the incident angle and the exit angle of light entering and leaving the third lens, making the light trend smooth and reducing the difficulty of aberration correction for the rear-end lens. More specifically, -0.63 < R5 / R6 < -0.39; -0.44 < (R5 + R6) / (R5 - R6) < -0.23; 0.92 < R5 / f < 1.48; -2.69 < R6 / f < -1.58.

[0066] In some embodiments, the distance BL on the optical axis from the image side surface of the seventh lens to the imaging surface and the effective focal length f of the optical lens satisfy: 0.29 < BL / f < 0.46. Satisfying the above range can endow the optical lens with the characteristic of long back focal length, meet the arrangement requirements of the rear-end chip, and reduce the assembly and processing difficulty.

[0067] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 0.25 mm / ° < IH / FOV < 0.3 mm / °. Satisfying the above range can ensure the field angle characteristic of the optical lens on the premise of meeting the image height requirement, so that the optical lens has good optical performance. More specifically, 0.26 mm / ° < IH / FOV < 0.29 mm / °.

[0068] In some embodiments, the combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens and the seventh lens satisfy: 0.35 < f123 / f4567 < 12. Satisfying the above range is conducive to balancing the distortion and astigmatism generated by the front and rear lenses of the optical lens by reasonably setting the optical power of the lens groups before and after the aperture, and improving the imaging quality of the optical lens. More specifically, 0.41 < f123 / f4567 < 10.95.

[0069] In some embodiments, the clear aperture radius d1 of the object side surface of the first lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.5 < d1 / (IH / 2) < 0.1. Meeting the above range can balance the small front aperture and large image plane of the optical lens, which is beneficial to the miniaturization of the optical lens. More specifically, 0.56 < d1 / (IH / 2) < 0.95.

[0070] In some embodiments, the radius of curvature R9 of the object side surface of the fifth lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: 0.05 < (R9 + R10) / (R9 - R10) < 0.4. Meeting the above range can reasonably control the radii of curvature of the object side surface and the image side surface of the fifth lens, which is beneficial to controlling the shape of the fifth lens, correcting the aberration generated by itself, and improving the imaging quality. More specifically, 0.1 < (R9 + R10) / (R9 - R10) < 0.38.

[0071] In some embodiments, the radius of curvature R5 of the object side surface of the seventh lens and the radius of curvature R6 of the image side surface of the seventh lens satisfy: -0.65 < (R13 + R14) / (R13 - R14) < -0.05. Meeting the above range can reasonably define the shapes of the object side surface and the image side surface of the seventh lens, enable the seventh lens to have an appropriate surface shape, help control the light trend in the marginal field of view, improve the imaging quality of the marginal field of view, and achieve high-quality collimation performance. More specifically, -0.5 < (R13 + R14) / (R13 - R14) < -0.1.

[0072] In some embodiments, the optical lens satisfies the conditional formula: 19 mm < f < 20 mm, 5.7 mm < EPD < 7.5 mm, 53 mm < TTL < 60 mm, 2.6 < Fno < 3.3, 5.2° < CRA < 9°, 5.3 mm < BL < 9.5 mm, 94° < FOV < 120°, 26 mm < IH < 33 mm; where f represents the effective focal length 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, CRA represents the principal ray angle of incidence at the maximum image height of the optical lens, BL represents the distance from the image side of the seventh lens to the imaging plane on the optical axis, FOV represents the maximum field angle of the optical lens, and IH represents the true image height corresponding to the maximum field angle of the optical lens. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least one or more advantages such as a large image plane, a large field angle, miniaturization, and a small CRA. More specifically, 19.26 mm < f < 19.36 mm, 6.18 mm < EPD < 6.92 mm, 54.9 mm < TTL < 58.1 mm, 2.79 < Fno < 3.13, 5.71° < CRA < 8.52°, 5.82 mm < BL < 8.73 mm, 103° < FOV < 111°, 28.35 mm < IH < 30.91 mm.

[0073] In some embodiments, the lens material of 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. The lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0074] 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 adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the 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 all adopt spherical lenses.

[0075] The present invention will be further described below with reference to several 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 tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention. Example 1

[0076] Please see Figure 1 The diagram shows a schematic of the structure of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 includes, along the optical axis from the object side to the imaging plane, the following components in sequence: 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 seventh lens L7, a filter G1, and a protective glass G2.

[0077] The first lens L1 has negative optical power, its object side S1 is concave, and its image side S2 is concave. The second lens L2 has negative optical power, its object side S3 is concave, and its image side S4 is concave. The third lens L3 has positive optical power, its object side S5 is convex, and its image side S6 is convex. The fourth lens L4 has negative optical power, its object side S7 is concave, and its image side S8 is concave. The fifth lens L5 has positive optical power, its object side S9 is convex, and its image side S10 is convex. The sixth lens L6 has negative optical power, its object side S11 is concave, and its image side S12 is convex. The seventh lens L7 has positive optical power, its object side S13 is convex, and its image side S14 is convex. The object-side surface S15 and the image-side surface S16 of filter G1 are both planar. The object side S17 and image side S18 of the protective glass G2 are both flat. The imaging plane S19 is a plane.

[0078] 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.

[0079] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1.

[0080] Table 1 In this embodiment, the F-Tan (Theta) distortion curve, MTF curve, and relative illumination curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 As shown.

[0081] Figure 2 The F-Tan(Theta) distortion curve of Example 1 is shown, which represents the F-Tan(Theta) distortion of light at different image heights on the imaging plane. The horizontal axis represents the F-Tan(Theta) distortion value (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Tan(Theta) distortion of the optical lens is controlled within -45% to 0, indicating that the optical lens can effectively correct distortion.

[0082] Figure 3 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in each field of view. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of this example is above 0.8 throughout the entire field of view. Within the range of 0 to 10 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating good imaging quality.

[0083] Figure 4 The relative illumination curves for Example 1 are shown, representing the relative illumination values ​​at different field-of-view angles on the imaging plane. The horizontal axis represents the half-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 88% at the maximum half-field angle, indicating that the optical lens has good relative illumination. Example 2

[0084] Please see Figure 5 The figure shows a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The difference between this embodiment and Embodiment 1 is that the object side surface S3 of the second lens L2 is a convex surface; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0085] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2.

[0086] Table 2 In this embodiment, the F-Tan (Theta) distortion curve, MTF curve, and relative illumination curve of the optical lens 200 are respectively as follows: Figure 6 , Figure 7 , Figure 8 As shown.

[0087] from Figure 6 As can be seen, the F-Tan (Theta) distortion of the optical lens is controlled within -45% to 0, indicating that the optical lens can effectively correct distortion.

[0088] from Figure 7 As can be seen, the MTF value of this embodiment is above 0.7 throughout the entire field of view. Within the range of 0 to 10 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating good imaging quality.

[0089] from Figure 8 As can be seen, the relative illumination value of the optical lens is still greater than 80% at the maximum half field of view, indicating that the optical lens has good relative illumination. Example 3

[0090] Please see Figure 9 The figure shows a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The difference between this embodiment and Embodiment 1 is that the image side surface S4 of the second lens L2 is a convex surface; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

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

[0092] Table 3 In this embodiment, the F-Tan (Theta) distortion curve, MTF curve, and relative illumination curve of the optical lens 300 are respectively as follows: Figure 10 , Figure 11 , Figure 12 As shown.

[0093] from Figure 10 As can be seen, the F-Tan (Theta) distortion of the optical lens is controlled within -45% to 0, indicating that the optical lens can effectively correct distortion.

[0094] from Figure 11 As can be seen, the MTF value of this embodiment is above 0.7 throughout the entire field of view. Within the range of 0 to 10 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating good imaging quality.

[0095] from Figure 12 As can be seen, the relative illumination value of the optical lens is still greater than 80% at the maximum half field of view, indicating that the optical lens has good relative illumination. Example 4

[0096] Please see Figure 13 The figure shows a schematic diagram of the structure of the optical lens 400 provided in Embodiment 4 of the present invention. The difference between this embodiment and Embodiment 1 is that: the object side surface S3 of the second lens L2 is a convex surface; the image side surface S8 of the fourth lens L4 is a convex surface; the image side surface S12 of the sixth lens L6 is a concave surface; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0097] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4.

[0098] Table 4 In this embodiment, the F-Tan (Theta) distortion curve, MTF curve, and relative illumination curve of the optical lens 400 are respectively as follows: Figure 14 , Figure 15 , Figure 16 As shown.

[0099] from Figure 14 As can be seen, the F-Tan (Theta) distortion of the optical lens is controlled within -45% to 0, indicating that the optical lens can effectively correct distortion.

[0100] from Figure 15 As can be seen, the MTF value of this embodiment is above 0.85 throughout the entire field of view. Within the range of 0 to 10 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating good imaging quality.

[0101] from Figure 16 As can be seen, the relative illumination value of the optical lens is still greater than 68% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0102] Please refer to Table 5 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, true image height IH corresponding to the maximum field of view, principal ray incident angle CRA at the maximum image height, maximum field of view FOV, distance BL from the image side of the seventh lens to the imaging plane on the optical axis, and the numerical values ​​corresponding to each conditional expression in each embodiment.

[0103] Table 5 In summary, the optical lens provided by the present invention employs seven lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the receiving quality of the lens, reduce aberrations, and enhance the imaging quality of the lens, giving the lens one or more advantages such as a large image plane, a large field of view, miniaturization, small CRA, and high collimation performance.

[0104] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0105] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An optical lens comprising seven lenses having optical power, characterized in that, It successively includes from the object side to the imaging surface along the optical axis: A first lens with a negative optical power, whose object side is concave and whose image side is concave; A second lens with a negative optical power; A third lens with a positive optical power, whose object side is convex and whose image side is convex; A fourth lens with a negative optical power, whose object side is concave; A fifth lens with a positive optical power, whose object side is convex and whose image side is convex; A sixth lens with a negative optical power, whose object side is concave; A seventh lens with a positive optical power, whose object side is convex and whose image side is convex; Wherein, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.6 < TTL / IH < 2.2; The combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 1 < f4567 / f < 2.

5.

2. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.6 < TTL / f < 3.3; The true image height IH corresponding to the maximum field angle of the optical lens and the radian value θ of the maximum half-field angle of the optical lens satisfy: 28mm < (IH / 2) / θ < 35mm.

3. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: The maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 31° < FOV / Fno < 43°; The true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.7 < IH / EPD < 5.

4.

4. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: The true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.3 < IH / f < 1.8; The total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 0.05 < 1°×TTL / (IH / 2) / (FOV / 2) < 0.

09.

5. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: The effective focal length f of the optical lens, the maximum field angle FOV of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 63° < f×FOV / IH < 78°; The clear aperture radius d1 of the object side of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 0.35 < d1 / (IH / 2) / tan(FOV / 2) < 0.

8.

6. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the true image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half-field angle of the optical lens satisfy: 0.75 < (IH / 2) / (f×θ) < 0.9; the half clear aperture d1 of the object side of the first lens and the half clear aperture d14 of the image side of the seventh lens satisfy: 0.4 < d1 / d14 < 0.

9.

7. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -3.4 < f1 / f < -1; the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.6 < f3 / f < 1.3; the focal length f1 of the first lens and the focal length f3 of the third lens satisfy: -5 < f1 / f3 < -1.

4.

8. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -22 < f2 / f < -0.9; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -29 < f4 / f < -1; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.7 < f5 / f < 1.3; the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -3.3 < f6 / f < -1.1; the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.4 < f7 / f < 2; the focal length f1 of the first lens and the combined focal length f123 of the first, second, and third lenses satisfy: -1.8 < f1 / f123 < -0.15; the focal length f3 of the third lens and the combined focal length f123 of the first, second, and third lenses satisfy: 0.05 < f3 / f123 < 0.

9.

9. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: 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: -2.7 < R1 / R2 < -0.9; 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 < (R1+R2) / (R1-R2) < 0.5; the radius of curvature R5 of the object side of the third lens and the radius of curvature R6 of the image side of the third lens satisfy: -0.7 < R5 / R6 < -0.3; the radius of curvature R5 of the object side of the third lens and the radius of curvature R6 of the image side of the third lens satisfy: -0.5 < (R5+R6) / (R5-R6) < -0.

2.

10. The optical lens according to any one of claims 1-9, characterized in that, The optical lens satisfies one or more of the following conditional expressions: The total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.77 < TTL / IH < 2.05; The combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens and the effective focal length f of the optical lens satisfy: 1.22 < f4567 / f < 2.26; The object-side curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: -4.5 < R1 / f < -1.7; The image-side curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: 0.7 < R2 / f < 2.9; The object-side curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: 0.8 < R5 / f < 1.6; The image-side curvature radius R6 of the third lens and the effective focal length f of the optical lens satisfy: -2.9 < R6 / f < -1.4.

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