Optical lens

Abstract

The application provides an optical lens, which has eight lenses with optical power, and sequentially comprises, along an optical axis from an object side to an imaging surface, a first lens with negative optical power, whose object side surface is a concave surface and whose image side surface is a convex surface; a second lens with positive optical power, whose object side surface is a convex surface and whose image side surface is a concave surface; a third lens with negative optical power, whose image side surface is a concave surface; a fourth lens with positive optical power, whose object side surface is a convex surface; a fifth lens with positive optical power, whose object side surface is a convex surface; a sixth lens with negative optical power, whose image side surface is a concave surface; a seventh lens with negative optical power, whose object side surface is a convex surface and whose image side surface is a concave surface; and an eighth lens with positive optical power. The optical lens provided by the application has one or more advantages, such as miniaturization, long focus, large image surface, large aperture, high imaging quality and the like, through specific surface shape matching and reasonable optical power distribution.

Description

Technical Field

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

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

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

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

[0005] The technical solution adopted by the present invention is as follows: An optical lens, the number of lenses with optical power is eight, and along the optical axis from the object side to the imaging surface, it sequentially includes: A first lens with negative optical power, its object side is concave, and its image side is convex; A second lens with positive optical power, its object side is convex, and its image side is concave; A third lens with negative optical power, its image side is concave; A fourth lens with positive optical power, its object side is convex; A fifth lens with positive optical power, its object side is convex; A sixth lens with negative optical power, its image side is concave; A seventh lens with negative optical power, its object side is convex, and its image side is concave; An eighth lens with positive optical power; Wherein, 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: 50° < f×FOV / IH < 60°; the focal length f2 of the second lens and the combined focal length f12 of the first lens and the second lens satisfy: 0.6 < f2 / f12 < 1.1.

[0006] 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 f2 of the second lens satisfy: 1.1 < f2 / f < 1.8; the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -5 < f1 / f2 < -2.2.

[0007] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 1.2 < f12 / f < 2.4; the combined focal length f12 of the first lens and the second lens and the combined focal length f34 of the third lens and the fourth lens satisfy: -0.6 < f12 / f34 < 0.

[0008] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the radius of curvature R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: 0.4 < R3 / f < 0.8; the radius of curvature R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: -1.7 < R4 / f < 4.1; the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: 0.1 < R3 / R4 < 0.4; the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: -0.8 < (R3 + R4) / (R3 - R4) < -0.4.

[0009] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.8 < TTL / f < 2.4; the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 3.2 < TTL / IH < 4.2.

[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 maximum field angle FOV of the optical lens satisfy: 0.98 < (IH / 2) / (f × tan(FOV / 2)) < 1.05; the maximum field angle FOV of the optical lens and the f-number Fno of the optical lens satisfy: 15° < FOV / Fno < 18°; 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: 0.5 < IH / f < 0.6.

[0011] Further preferably, the optical lens satisfies one or more of the following conditional expressions: 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: 0.47 < TTL / (IH / 2) / (FOV / 2)×1° < 0.53; 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: 4.7 < d1 / (IH / 2) / tan(FOV / 2) < 6.

[0012] 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: -6.7 < f1 / f < -3.4; The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.5 < f3 / f < -0.8; The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.9 < f4 / f < 3; The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.5 < f5 / f < 1; The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.4 < f6 / f < -0.4; The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -10.5 < f7 / f < -1.3; The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 1 < f8 / f < 21.

[0013] Further preferably, 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 effective focal length f of the optical lens satisfy: -1.9 < R1 / f < -0.8; The radius of curvature R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: -3 < R2 / f < -1.1; 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: 0.4 < R1 / R2 < 0.8; 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: -0.4 < (R1 - R2) / (R1 + R2) < -0.1.

[0014] 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: 53.62° < f×FOV / IH < 56.67°; The focal length f2 of the second lens and the combined focal length f12 of the first lens and the second lens satisfy: 0.72 < f2 / f12 < 0.93.

[0015] The optical lens provided by this invention uses eight lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as miniaturization, telephoto, large image plane, large aperture, and high imaging quality. Attached Figure Description

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

[0017] Figure 2 This is an MTF curve of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 3 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0019] Figure 4 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0020] Figure 5 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0021] Figure 6 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0022] Figure 7 This is a schematic diagram of the optical lens structure in Embodiment 4 of the present invention.

[0023] Figure 8 This is the MTF curve of the optical lens in Embodiment 4 of the present invention.

[0024] Figure 9 This is a schematic diagram of the optical lens structure in Embodiment 5 of the present invention.

[0025] Figure 10 This is the MTF curve of the optical lens in Embodiment 5 of the present invention.

[0026] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following will describe the present application in detail with reference to the drawings and in combination with the embodiments.

[0034] The optical lens provided by the embodiment of the present invention has eight lenses with optical powers. They are, in order from the object side to the imaging surface along the optical axis, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens.

[0035] In some embodiments, the first lens may have a negative optical power, its object side is concave, and its image side is convex. The second lens may have a positive optical power, its object side is convex, and its image side is concave. The third lens may have a negative optical power, its object side may be concave or convex, and its image side is concave. The fourth lens may have a positive optical power, its object side is convex, and its image side may be concave or convex. The fifth lens may have a positive optical power, its object side is convex, and its image side may be concave or convex. The sixth lens may have a negative optical power, its object side may be concave or convex, and its image side is concave. The seventh lens may have a negative optical power, its object side is convex, and its image side is concave. The eighth lens may have a positive optical power, its object side may be concave or convex, and its image side may be concave or convex.

[0036] In some embodiments, the optical lens may further include an aperture, and the aperture may be located between the first lens and the second 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 first lens and the second lens, it is convenient for the correction of aperture aberration.

[0037] In some embodiments, the optical lens may further include a filter and a protective glass. The filter and the protective glass may be sequentially arranged along the optical axis between the eighth 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. The protective glass plays a role in protecting the optical lens and preventing the photosensitive chip from being damaged and affecting the imaging effect of the lens.

[0038] In some embodiments, 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: 50° < f × FOV / IH < 60°. Meeting the above range, by reasonably restricting the relationship between the focal length, field angle, and image height of the optical lens, it is beneficial to achieve the balance between the large field angle and large target surface imaging of the optical lens. More specifically, 53.62° < f × FOV / IH < 56.67°.

[0039] In some embodiments, the focal length f2 of the second lens and the combined focal length f12 of the first lens and the second lens satisfy: 0.6 < f2 / f12 < 1.1. Satisfying the above range can achieve a greater degree of convergence of the incident light and allow more light to enter the system, which is beneficial to improving the light input of the lens and realizing the large aperture performance of the lens, enabling the lens to achieve high-definition imaging even in a relatively dark environment. More specifically, 0.72 < f2 / f12 < 0.93.

[0040] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.1 < f2 / f < 1.8. Satisfying the above conditional formula enables the second lens to have the function of converging light. When paired with the negative optical power of the first lens, it can further converge the light passing through the first lens, reduce the height of the peripheral light, which is beneficial to reducing the aperture of the rear lens, and at the same time is beneficial to balancing aberrations and improving resolution. More specifically, 1.22 < f2 / f < 1.67.

[0041] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -5 < f1 / f2 < -2.2. Satisfying the above range, by reasonably setting the first lens and the second lens with negative and positive optical powers, the distribution of the focal lengths of the front lenses of the optical lens can be balanced, the correction pressure of the rear lens for aberrations can be reduced, and the imaging quality of the optical lens can be improved. More specifically, -4.57 < f1 / f2 < -2.41.

[0042] In some embodiments, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 1.2 < f12 / f < 2.4. Satisfying the above range, the combined focal length of the first lens and the second lens provides positive optical power for the optical lens, which can enable the front lens group of the optical lens to have a strong light deflection ability, which is beneficial to increasing the field angle of the optical lens. More specifically, 1.35 < f12 / f < 2.15.

[0043] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f34 of the third lens and the fourth lens satisfy: -0.6 < f12 / f34 < 0. Satisfying the above range, by reasonably setting the relationship between the optical powers of the combined focal length of the first lens and the second lens and the combined focal length of the third lens and the fourth lens in the lens, the incident light can be converged to a certain extent, which is beneficial to realizing the telephoto performance of the lens. More specifically, -0.57 < f12 / f34 < -0.02.

[0044] In some embodiments, the radius of curvature R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: 0.4 < R3 / f < 0.8; the radius of curvature R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: -1.7 < R4 / f < 4.1; the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: 0.1 < R3 / R4 < 0.4; the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: -0.8 < (R3 + R4) / (R3 - R4) < -0.4. Meeting the above ranges, by setting the second lens to have a double convex surface type, it is beneficial to better achieve the convergence of light, shorten the distance for light to reach the next lens, and is beneficial to reducing the total length of the optical lens. More specifically, 0.51 < R3 / f < 0.7; 1.83 < R4 / f < 3.78; 0.13 < R3 / R4 < 0.33; -0.76 < (R3 + R4) / (R3 - R4) < -0.51.

[0045] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.8 < TTL / f < 2.4. Meeting the above range can effectively limit the length of the lens and is beneficial to achieving the miniaturization of the optical lens. More specifically, 1.96 < TTL / f < 2.18.

[0046] 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: 3.2 < TTL / IH < 4.2. Meeting the above range ensures that, with the same total length of the lens, it has a larger image plane, can match a larger-size imaging chip to achieve high-definition imaging, and better realizes the balance between the small total length and the large image plane of the lens. More specifically, 3.56 < TTL / IH < 3.89.

[0047] 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 maximum field angle FOV of the optical lens satisfy: 0.98 < (IH / 2) / (f × tan(FOV / 2)) < 1.05. Meeting the above range controls the optical lens to have a small distortion and can provide a high-definition imaging effect.

[0048] In some embodiments, the maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 15° < FOV / Fno < 18°. Meeting the above range is beneficial to expanding the field angle of the lens and increasing the aperture of the lens, and realizing the characteristics of a large aperture. More specifically, 16.66° < FOV / Fno < 16.68°.

[0049] In some embodiments, 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: 0.5 < IH / f < 0.6. Meeting the above range and controlling the image height and focal length of the optical lens within a reasonable range helps the optical lens to have the characteristic of a large image plane and improves the imaging quality. More specifically, 0.52 < IH / f < 0.57.

[0050] In some embodiments, the overall 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: 0.47 < TTL / (IH / 2) / (FOV / 2)×1° < 0.53. Meeting the above range helps to control the structural balance of the overall length, field 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 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: 4.7 < d1 / (IH / 2) / tan(FOV / 2) < 6. 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, 5.13 < d1 / (IH / 2) / tan(FOV / 2) < 5.43.

[0052] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -6.7 < f1 / f < -3.4. Meeting the above range and setting the first lens of the optical lens as a negative focal power lens can capture the light rays entering the optical lens at a large angle, expand the field angle range of the optical lens, and is also beneficial to reducing the sensitivity of the optical lens and realizing the miniaturized design of the optical lens. More specifically, -6.13 < f1 / f < -3.74.

[0053] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.5 < f3 / f < -0.8. Meeting the above range and setting the third lens as a negative focal power can further control the incident angle of light, expand the field angle range of the optical lens, increase the back focal length of the optical lens, avoid interference between the lens and the photosensitive chip, and is also conducive to the correction of aberration, which can further improve the imaging quality of the optical lens. More specifically, -1.38 < f3 / f < -0.87.

[0054] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.9 < f4 / f < 3. Meeting the above range, by setting the fourth lens to have a positive optical power, the light rays from the first three lenses can be further converged, and the aberration problems brought by the first three lenses can be corrected, and the aberration of the edge field of view can be effectively improved, thus enhancing the overall imaging quality of the optical lens. More specifically, 1.01 < f4 / f < 2.73.

[0055] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.5 < f5 / f < 1. Meeting the above range, defining that the fifth lens has a positive optical power is beneficial to light convergence, thus effectively correcting chromatic aberration, and can finally correct the aberration generated by the decentration difference of each lens on the object side, that is, the decentration sensitivity of the optical lens can be reduced, and the astigmatism generated by the decentration of each lens on the object side can be suppressed, thereby realizing the correction of the aberration of the optical lens and enhancing the imaging resolution. More specifically, 0.6 < f5 / f < 0.95.

[0056] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.4 < f6 / f < -0.4. Meeting the above range, setting the sixth lens to have a negative optical power makes the large-field light rays slowly rise, changing the parallel light trend of the light beam to a divergent trend, which is beneficial to controlling the back focal length of the lens and is beneficial to achieving a large target surface. More specifically, -1.25 < f6 / f < -0.47.

[0057] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -10.5 < f7 / f < -1.3. Meeting the above range is beneficial to expanding the width of the light beam, making the wide light beam fully incident on the imaging surface of the optical lens, enabling the optical lens to have a wider field of view range, and being beneficial to achieving high-pixel imaging. More specifically, -9.61 < f7 / f < -1.45.

[0058] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 1 < f8 / f < 21. Meeting the above range, setting the eighth lens to have a positive optical power is beneficial to light convergence, making the light ray trend smoothly transition to the rear, reducing the height of the light rays incident on the rear, slowing down the upward trend of the light rays, avoiding the light energy loss caused by the excessive main ray angle of the large-field light rays when reaching the imaging surface, being beneficial to increasing the illuminance of the edge field of view, and being beneficial to achieving a short optical total length. More specifically, 1.14 < f8 / f < 19.22.

[0059] In some embodiments, the radius of curvature R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -1.9 < R1 / f < -0.8; the radius of curvature R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: -3 < R2 / f < -1.1; 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: 0.4 < R1 / R2 < 0.8; 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: -0.4 < (R1 - R2) / (R1 + R2) < -0.1. Meeting the above ranges enables the first lens to have a meniscus shape, reduces the requirement for the distance of incident light from the optical axis, is beneficial to reducing the front aperture of the lens, and enables the light to transition smoothly in the lens. More specifically, -1.7 < R1 / f < -0.88; -2.79 < R2 / f < -1.27; 0.48 < R1 / R2 < 0.74; -0.35 < (R1 - R2) / (R1 + R2) < -0.14.

[0060] In some embodiments, 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: 0.9 < IH / EPD < 1.1. Meeting the above conditions enables the field of view and light flux to be balanced and improves the imaging quality of the lens. More specifically, 0.94 < IH / EPD < 1.02.

[0061] In some embodiments, the distance BL on the optical axis from the image side surface of the eighth lens to the imaging surface and the effective focal length f of the optical lens satisfy: 0.17 < BL / f < 0.29. Meeting the above range can provide the optical lens with the characteristic of a long back focal length, can meet the arrangement requirements of the rear-end chip, and reduces the assembly and processing difficulty.

[0062] In some embodiments, the combined focal length f34 of the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: -60 < f34 / f < -2.5. Meeting the above range, the combined focal length of the third lens and the fourth lens provides a negative optical power for the optical lens, fully diverges the light to the fifth lens, reduces the risk of ghost imaging at the same time, and improves the imaging quality. More specifically, -54.84 < f34 / f < -2.7.

[0063] In some embodiments, the combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: 1.5 < f56 / f < 35. Meeting the above range, the combined focal length of the fifth lens and the sixth lens provides a positive optical power for the optical lens, can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, and can also balance the aberration of the optical lens, improving the imaging quality of the optical lens. More specifically, 1.7 < f56 / f < 31.69.

[0064] In some embodiments, the combined focal length f2345678 of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.7 < f2345678 / f < 1. Satisfying the above relational expression, by controlling the relationship between the rear diaphragm lens group and the effective focal length of the optical lens, it is beneficial to correct aberration and is easy for overall aberration correction and image quality balance. More specifically, 0.82 < f2345678 / f < 0.92.

[0065] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: 0 < f12 / f56 < 1.3; the combined focal length f34 of the third lens and the fourth lens and the combined focal length f56 of the fifth lens and the sixth lens satisfy: -2.5 < f34 / f56 < -0.8. Satisfying the above ranges, by reasonably setting the relationship of the combined focal lengths of each lens, it is beneficial to the smooth transition of light, and at the same time correct various aberrations of the optical lens, improving the imaging quality of the optical lens. More specifically, 0.03 < f12 / f56 < 1.17; -2.24 < f34 / f56 < -0.83.

[0066] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f2345678 of the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 1.4 < f12 / f2345678 < 2.8. Satisfying the above range makes the first lens and the second lens of the optical lens have a suitable proportion of optical power, and can make the large-angle light entering the lens be fully transmitted to the rear light system, obtaining a larger field of view range and higher relative illumination. More specifically, 1.5 < f12 / f2345678 < 2.59.

[0067] In some embodiments, the optical lens satisfies the following conditional expressions: 19 mm < f < 24 mm; 10.5 mm < EPD < 13 mm; 38 mm < TTL < 48 mm; 1.7 < Fno < 1.9; 20° < CRA < 24°; 3.5 mm < BL < 6.5 mm; 28° < FOV < 32°; 11 mm < IH < 12 mm. In the above conditional expressions, 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 chief ray angle of incidence of the optical lens, BL represents the distance from the image side of the eighth lens to the imaging surface 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 ranges, the optical lens has at least one or more advantages such as miniaturization, long focal length, large aperture, and large target surface. More specifically, 20.73 mm < f < 21.92 mm; 11.51 mm < EPD < 12.18 mm; 41 mm < TTL < 45.02 mm; 1.79 < Fno < 1.81; 21.77° < CRA < 23.03°; 3.69 mm < BL < 6 mm; 29.99° < FOV < 30.01°; 11.49 mm < IH < 11.69 mm.

[0068] 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 optical lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0069] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth 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 seventh lens of the present invention adopts an aspherical lens; the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the eighth lens adopt spherical lenses.

[0070] In various embodiments of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equation: ; Where z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the quadratic surface coefficient, and B, C, D, E, F, G, and H are the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth order surface coefficients, respectively.

[0071] 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

[0072] 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, an aperture ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter G1, and a protective glass G2.

[0073] Among them, the first lens L1 has negative optical power, its object side S1 is concave, and its image side S2 is convex. The second lens L2 has positive optical power, its object side S3 is convex, and its image side S4 is concave. The third lens L3 has negative optical power, its object side S5 is convex, and its image side S6 is concave. The fourth lens L4 has positive optical power, its object side S7 is convex, 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 concave. The seventh lens L7 has negative optical power, its object side S13 is convex, and its image side S14 is concave. The eighth lens L8 has positive optical power, its object side S15 is convex, and its image side S16 is concave. The object-side surface S17 and the image-side surface S18 of filter G1 are both planar. The object side S19 and image side S20 of the protective glass G2 are both flat. The imaging plane S21 is a plane.

[0074] The seventh lens L7 is a glass aspherical lens; 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 eighth lens L8 are glass spherical lenses.

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

[0076] Table 1-1 The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0077] Table 1-2 Figure 2 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in various fields of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents MTF value. As can be seen from the figure, the MTF value of this example is above 0.5 throughout the entire field of view. Within the range of 0–120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies. Example 2

[0078] Please see Figure 3 The figure shows a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S5 of the third lens L3 is concave, the image side surface S16 of the eighth lens L8 is convex, and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0079] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0080] Table 2-1 The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0081] Table 2-2 from Figure 4 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions. Example 3

[0082] Please see Figure 5 The figure shown is a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that the image side surface S10 of the fifth lens L5 is concave, the object side surface S11 of the sixth lens L6 is convex, and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0083] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0084] Table 3-1 The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0085] Table 3-2 from Figure 6 As can be seen, the MTF value of this embodiment is above 0.5 throughout the entire field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions. Example 4

[0086] Please see Figure 7 The figure shows a schematic diagram of the structure of the optical lens 400 provided in Embodiment 4 of the present invention. The main difference between this embodiment and Embodiment 1 is that: the object side S5 of the third lens L3 is concave; the image side S8 of the fourth lens L4 is convex; the object side S15 of the eighth lens L8 is concave; the image side S16 of the eighth lens L8 is convex; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0087] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0088] Table 4-1 The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0089] Table 4-2 from Figure 8 As can be seen, the MTF value of this embodiment is above 0.45 throughout the entire field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions. Example 5

[0090] Please see Figure 9The figure shows a schematic diagram of the structure of the optical lens 500 provided in Embodiment 5 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S15 of the eighth lens L8 is concave; the image side surface S16 of the eighth lens L8 is convex; and 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 500 in Example 5 are shown in Table 5-1.

[0092] Table 5-1 The surface profile parameters of the aspherical lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0093] Table 5-2 from Figure 10 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view, demonstrating good imaging quality and detail resolution in both low and high frequency conditions.

[0094] Please refer to Table 6 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 eighth lens to the imaging plane on the optical axis, and the numerical value corresponding to each conditional expression in each embodiment.

[0095] Table 6 In summary, the optical lens provided by the present invention uses eight lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as miniaturization, telephoto, large image plane, large aperture, and high imaging quality.

[0096] 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.

[0097] 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 eight lenses having optical power, characterized in that, It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with negative optical power, whose object side is concave and whose image side is convex; A second lens with positive optical power, whose object side is convex and whose image side is concave; A third lens with negative optical power, whose image side is concave; A fourth lens with positive optical power, whose object side is convex; A fifth lens with positive optical power, whose object side is convex; A sixth lens with negative optical power, whose image side is concave; A seventh lens with negative optical power, whose object side is convex and whose image side is concave; An eighth lens with positive optical power; Wherein, 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: 50° < f×FOV / IH < 60°; the focal length f2 of the second lens and the combined focal length f12 of the first lens and the second lens satisfy: 0.6 < f2 / f12 < 1.

1.

2. 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 f2 of the second lens satisfy: 1.1 < f2 / f < 1.8; the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -5 < f1 / f2 < -2.

2.

3. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 1.2 < f12 / f < 2.4; the combined focal length f12 of the first lens and the second lens and the combined focal length f34 of the third lens and the fourth lens satisfy: -0.6 < f12 / f34 < 0.

4. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the curvature radius R3 of the object side of the second lens and the effective focal length f of the optical lens satisfy: 0.4 < R3 / f < 0.8; the curvature radius R4 of the image side of the second lens and the effective focal length f of the optical lens satisfy: -1.7 < R4 / f < 4.1; the curvature radius R3 of the object side of the second lens and the curvature radius R4 of the image side of the second lens satisfy: 0.1 < R3 / R4 < 0.4; the curvature radius R3 of the object side of the second lens and the curvature radius R4 of the image side of the second lens satisfy: -0.8 < (R3 + R4) / (R3 - R4) < -0.

4.

5. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.8 < TTL / f < 2.4; The overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 3.2 < TTL / IH < 4.

2.

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 maximum field angle FOV of the optical lens satisfy: 0.98 < (IH / 2) / (f×tan(FOV / 2)) < 1.05; the maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 15° < FOV / Fno < 18°; 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: 0.5 < IH / f < 0.

6.

7. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the overall 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: 0.47 < TTL / (IH / 2) / (FOV / 2)×1° < 0.53; the half-aperture value 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: 4.7 < d1 / (IH / 2) / tan(FOV / 2) < 6.

8. 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: -6.7 < f1 / f < -3.4; the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.5 < f3 / f < -0.8; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.9 < f4 / f < 3; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.5 < f5 / f < 1; the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.4 < f6 / f < -0.4; the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -10.5 < f7 / f < -1.3; the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 1 < f8 / f < 21.

9. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the curvature radius R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -1.9 < R1 / f < -0.8; the curvature radius R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: -3 < R2 / f < -1.1; 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: 0.4 < R1 / R2 < 0.8; 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: -0.4 < (R1 - R2) / (R1 + R2) < -0.

1.

10. 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: 53.62° < f × FOV / IH < 56.67°; the focal length f2 of the second lens and the combined focal length f12 of the first lens and the second lens satisfy: 0.72 < f2 / f12 < 0.93.

Images