Optical lens

Abstract

The invention provides an optical lens, which comprises eight lenses with focal power and sequentially comprises a first lens with negative focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with negative focal power from an object side to an imaging surface along an optical axis, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the object side surface of the third lens is a concave surface; the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a concave surface; the object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a convex surface; the object side surface of the seventh lens is a concave surface, and the image side surface of the seventh lens is a concave surface near the optical axis; and the object side surface of the eighth lens is a convex surface near the optical axis, and the image side surface of the eighth lens is a convex surface. The optical lens provided by the invention has one or more advantages of large aperture, large field angle, large image plane and the like.

Description

Technical Field

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

[0002] Fisheye lenses can capture a wide field of view; however, this wide angle also introduces significant barrel distortion, where objects at the edges of the image, which should be horizontal or vertical, appear warped and distorted, while only objects in the central area remain relatively unchanged. Furthermore, fisheye lenses suffer from other drawbacks: edge image quality is easily degraded, aberration correction is difficult, and distortion is significant. Despite these issues, through advanced optical design and post-processing algorithm correction, fisheye lenses, with their unique advantages, are widely used in scene monitoring, satellite positioning, robot navigation, micro-intelligent systems, and engineering measurement, providing panoramic vision solutions for multiple industries and facilitating efficient and accurate monitoring and positioning. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide an optical lens with the advantage of excellent image quality.

[0004] The technical solution adopted in this invention is as follows:

[0005] An optical lens has eight lenses with optical power, arranged sequentially along the optical axis from the object side to the imaging plane:

[0006] The first lens with negative optical power has a convex object side and a concave image side.

[0007] A second lens with negative optical power has a convex object side and a concave image side.

[0008] A third lens with negative optical power has a concave object side.

[0009] The fourth lens with positive optical power has a convex object-side surface and a convex image-side surface.

[0010] The fifth lens with positive optical power has a convex object side and a concave image side.

[0011] The sixth lens with positive optical power has a convex object-side surface and a convex image-side surface.

[0012] The seventh lens with negative optical power has a concave object side and a concave image side near the optical axis.

[0013] The eighth lens with positive optical power has an object-side surface that is convex near the optical axis and an image-side surface that is convex.

[0014] Among them, 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: 1.14 < (IH / 2) / (f×θ) < 1.19; the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 11 < f5 / f < 16.

[0015] Further preferably, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 13 < TTL / f < 15.5; 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: 3.3 < TTL / IH < 3.8.

[0016] Further preferably, 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: 6 < IH / EPD < 7; 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: 4 < IH / f < 4.2.

[0017] Further preferably, 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: 0.06° < TTL / (IH / 2) / (FOV / 2) < 0.08°; the half clear aperture 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: -0.54 < d1 / (IH / 2) / tan(FOV / 2) < -0.4.

[0018] Further preferably, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -8.5 < f1 / f < -5; 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: 8.5 < R1 / f < 9.5; 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: 2.5 < R2 / f < 4.

[0019] Further preferably, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -4.4 < f2 / f < -2.8; 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: 2.4 < R3 / f < 4.2; 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: 0.95 < R4 / f < 1.5.

[0020] More preferably, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -4.5 < f3 / f < -3.3; the object-side curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: -4.3 < R5 / f < -1.9; the image-side curvature radius R4 of the second lens and the object-side curvature radius R5 of the third lens satisfy: -0.52 < R4 / R5 < -0.32.

[0021] More preferably, the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: -4 < f1234 / f < -2; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 3 < f5678 / f < 3.5; the combined focal length f67 of the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 9 < f67 / f < 17; the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -1.2 < f1234 / f5678 < -0.7; the combined focal length f67 of the sixth lens and the seventh lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 3 < f67 / f5678 < 5.

[0022] More preferably, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: 0.7 < f2 / f3 < 1.3; the image-side curvature radius R4 of the second lens and the object-side curvature radius R5 of the third lens satisfy: -3.1 < (R4 - R5) / (R4 + R5) < -1.9.

[0023] More preferably, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: 0.22 < f4 / f5 < 0.32; the object-side curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: 3 < R7 / f < 6.5; the image-side curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -1200 < R8 / f < -7; the object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: 2.1 < R9 / f < 4.2; the image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: 2 < R10 / f < 5.5.

[0024] The optical lens provided by this invention has eight lenses with 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 large aperture, large field of view, and large image plane. Attached Figure Description

[0025] 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:

[0026] Figure 1 This is a schematic diagram of the optical lens structure in Embodiment 1 of the present invention.

[0027] Figure 2 This is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3 This is an axial aberration curve of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 4 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 5 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0031] Figure 6 This is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 7 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 8 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0034] Figure 9 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0035] Figure 10 This is a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0036] Figure 11 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0037] Figure 12 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0038] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] This invention provides an optical lens with eight lenses having optical power, arranged sequentially along the optical axis from the object side to the imaging plane as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

[0047] In some embodiments, the first lens may have negative optical power, its object-side surface may be convex, and its image-side surface may be concave. The second lens may have negative optical power, its object-side surface may be convex, and its image-side surface may be concave. The third lens may have negative optical power, its object-side surface may be concave, and its image-side surface may be either convex or concave. The fourth lens may have positive optical power, its object-side surface may be convex, and its image-side surface may be convex. The fifth lens may have positive optical power, its object-side surface may be convex, and its image-side surface may be concave. The sixth lens may have positive optical power, its object-side surface may be convex, and its image-side surface may be convex. The seventh lens may have negative optical power, its object-side surface may be concave, and its image-side surface may be concave near the optical axis. The eighth lens may have positive optical power, its object-side surface may be convex near the optical axis, and its image-side surface may be convex.

[0048] In some embodiments, the optical lens may also include an aperture stop, which may be located between the fourth and fifth lenses. It is understood that the aperture stop is used to limit the amount of light entering the lens, thereby altering the brightness of the image.

[0049] In some embodiments, the optical lens may further include a filter and a protective glass, which are sequentially disposed along the optical axis between the eighth lens and the imaging plane. The filter is used to filter out interfering light, preventing it from reaching the imaging plane of the optical lens and affecting normal imaging. The protective glass protects the optical lens, preventing damage to the image sensor, and improves the lens's shock and scratch resistance, while having almost no impact on the image quality of the optical lens.

[0050] In some embodiments, the sixth and seventh lenses can be cemented together to form a cemented lens, which can effectively correct chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberrations of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0051] 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: 1.14 < (IH / 2) / (f×θ) < 1.19; the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 11 < f5 / f < 16. Satisfying the above ranges can control the distortion of the optical lens and provide a clear imaging effect. At the same time, it is beneficial to correct the aberration of the optical lens. More specifically: 11.5 < f5 / f < 15.51.

[0052] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 13 < TTL / f < 15.5; 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: 3.3 < TTL / IH < 3.8. Satisfying the above ranges can effectively limit the length of the lens and achieve miniaturization of the lens. At the same time, with the same overall length of the lens ensured, it has a larger image plane, can match a larger-size imaging chip to achieve high-definition imaging, and can preferably achieve the balance between the small overall length and the large image plane of the lens. More specifically: 13.94 < TTL / f < 15.2; 3.47 < TTL / IH < 3.73.

[0053] 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: 6 < IH / EPD < 7; 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: 4 < IH / f < 4.2. Satisfying the above ranges, the optical lens can ensure sufficient image plane brightness in the edge field of view, prevent vignetting, and thus improve the imaging quality. At the same time, it can achieve an ultra-large field angle and imaging range, can achieve the large image plane characteristic while ensuring the depth of field of the optical lens, and thus improve the imaging quality of the optical system. More specifically: 6.53 < IH / EPD < 6.74; 4 < IH / f < 4.14.

[0054] 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: 0.06° < TTL / (IH / 2) / (FOV / 2) < 0.08°; the half clear aperture 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: -0.54 < d1 / (IH / 2) / tan(FOV / 2) < -0.4. Satisfying the above ranges is beneficial to balance the relationship among the overall length, image height, and field angle of the optical lens. At the same time, it can reasonably arrange the overall geometric shape of the optical lens and improve its structural stability.

[0055] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -8.5 < f1 / f < -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: 8.5 < R1 / f < 9.5; the curvature radius R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: 2.5 < R2 / f < 4. Meeting the above ranges and reasonably defining the proportion of the optical power and the surface shape of the first lens is beneficial to collecting edge field light into the subsequent system as much as possible, achieving large-angle light collection, and increasing the light flux. More specifically: -8.02 < f1 / f < -5.2; 8.69 < R1 / f < 9.37; 2.76 < R2 / f < 3.93.

[0056] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -4.4 < f2 / f < -2.8; the curvature radius R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: 2.4 < R3 / f < 4.2; the curvature radius R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: 0.95 < R4 / f < 1.5. Meeting the above ranges and reasonably defining the proportion of the optical power and the surface shape of the second lens is beneficial to reducing the difficulty of chromatic aberration correction of the optical lens. More specifically: -4.23 < f2 / f < -3.01; 2.52 < R3 / f < 3.97; 0.97 < R4 / f < 1.41.

[0057] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -4.5 < f3 / f < -3.3; the curvature radius R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy: -4.3 < R5 / f < -1.9; the curvature radius R4 of the image side surface of the second lens and the curvature radius R5 of the object side surface of the third lens satisfy: -0.52 < R4 / R5 < -0.32. Meeting the above ranges is beneficial to correcting field curvature, improving edge image quality, and further improving the imaging quality of the optical lens. More specifically: -4.26 < f3 / f < -3.5; -4.21 < R5 / f < -1.93.

[0058] In some embodiments, the combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens and the effective focal length f of the optical lens satisfy: -4 < f1234 / f < -2; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens, and the eighth lens and the effective focal length f of the optical lens satisfy: 3 < f5678 / f < 3.5; the combined focal length f67 of the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 9 < f67 / f < 17; the combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy: -1.2 < f1234 / f5678 < -0.7; the combined focal length f67 of the sixth lens and the seventh lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy: 3 < f67 / f5678 < 5. Meeting the above ranges is beneficial to balancing various aberrations of the system and improving the overall imaging quality. More specifically: -3.79 < f1234 / f < -2.24; 3.1 < f5678 / f < 3.34; 9.67 < f67 / f < 15.97; -1.15 < f1234 / f5678 < -0.71; 3.1 < f67 / f5678 < 4.81.

[0059] In some embodiments, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: 0.7 < f2 / f3 < 1.3; the image-side curvature radius R4 of the second lens and the object-side curvature radius R5 of the third lens satisfy: -3.1 < (R4 - R5) / (R4 + R5) < -1.9. Meeting the above ranges is beneficial to correcting field curvature, improving the edge image quality, and further improving the imaging quality of the optical lens. More specifically: 0.7 < f2 / f3 < 1.21; -3.08 < (R4 - R5) / (R4 + R5) < -1.99.

[0060] In some embodiments, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: 0.22 < f4 / f5 < 0.32; the radius of curvature R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 3 < R7 / f < 6.5; the radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -1200 < R8 / f < -7; the radius of curvature R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 2.1 < R9 / f < 4.2; the radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 2 < R10 / f < 5.5. Meeting the above ranges can effectively correct chromatic aberration, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality. More specifically: 3.27 < R7 / f < 6.37; -1176.07 < R8 / f < -7.13; 2.16 < R9 / f < 4.07; 2.14 < R10 / f < 5.39.

[0061] 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: 45° < f×FOV / IH < 50°. Meeting the above range is beneficial to balance the relationship among the focal length, field angle, and image height of the optical lens. More specifically: 48.41° < f×FOV / IH < 49.85°.

[0062] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 3.3 < f4 / f < 4.3. Meeting the above range is beneficial to reduce the aberration generated by the front lens. More specifically: 3.5 < f4 / f < 4.01.

[0063] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.5 < f6 / f < 2.1. Meeting the above range can effectively converge light, reduce the difficulty of correcting the edge field distortion, and improve the overall imaging quality. More specifically: 1.56 < f6 / f < 1.97.

[0064] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.7 < f7 / f < -1.3. Meeting the above range is beneficial to increase the divergence degree of light and achieve large target surface imaging of the lens. More specifically: -1.6 < f7 / f < -1.33.

[0065] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 2.2 < f8 / f < 2.6; the radius of curvature R15 of the object side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 2 < R15 / f < 2.8; the radius of curvature R16 of the image side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -2.7 < R16 / f < -1.7. Satisfying the above ranges and reasonably defining the proportion of the optical power and the surface shape of the eighth lens is beneficial to balancing the astigmatism and field curvature of the optical lens and improving the imaging quality of the optical lens. More specifically: 2.33 < f8 / f < 2.42; 2.05 < R15 / f < 2.78; -2.61 < R16 / f < -1.75.

[0066] In some embodiments, 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) < 0.55. Satisfying the above range is beneficial to collecting as much marginal field light as possible into the rear system, achieving large-angle light collection, and increasing the light flux. More specifically: 0.4 < (R1 - R2) / (R1 + R2) < 0.53.

[0067] In some embodiments, 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: 0.4 < (R3 - R4) / (R3 + R4) < 0.5. Satisfying the above range is beneficial to reducing the difficulty of chromatic aberration correction of the optical lens. More specifically: 0.43 < (R3 - R4) / (R3 + R4) < 0.49.

[0068] In some embodiments, the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: -18 < (R7 - R8) / (R7 + R8) < -1. Satisfying the above range is beneficial to reducing the aberration generated by the front lens. More specifically: -17.23 < (R7 - R8) / (R7 + R8) < -1.

[0069] In some embodiments, the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: 2.5 < (R11 - R12) / (R11 + R12) < 3.7. Satisfying the above range can effectively converge light, reduce the difficulty of marginal field distortion correction, and improve the overall imaging quality. More specifically: 2.64 < (R11 - R12) / (R11 + R12) < 3.6.

[0070] In some embodiments, the radius of curvature R13 of the object side surface of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy: -1.75 < (R13 - R14) / (R13 + R14) < -1.4. Meeting the above range is beneficial to increasing the divergence degree of light rays and achieving large target surface imaging of the lens. More specifically: -1.7 < (R13 - R14) / (R13 + R14) < -1.46.

[0071] In some embodiments, the optical lens satisfies the following conditional expressions: 1.3 mm < f < 1.4 mm; 190° < FOV < 210°; 0.8 mm < EPD < 0.85 mm; 19 mm < TTL < 21 mm; 1.6 < Fno < 1.7; 5.3 mm < IH < 5.7 mm; 10° < CRA < 15°; 2.4 mm < BL < 2.5 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the main ray incident angle at the maximum image height of the optical lens, and BL represents the distance from the image side surface of the seventh lens of the optical lens to the imaging surface on the optical axis. Meeting the above range, the optical lens has at least one or more advantages such as a large aperture, a large field of view angle, and a large image surface. More specifically: 1.32 mm < f < 1.38 mm; 199° < FOV < 201°; 0.81 mm < EPD < 0.85 mm; 19.06 mm < TTL < 20.42 mm; 1.62 < Fno < 1.64; 5.48 mm < IH < 5.5 mm; 10.18° < CRA < 14.08°; 2.42 mm < BL < 2.44 mm.

[0072] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, 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 adopts a lens structure with a hybrid combination of eight glass and plastic lenses. More specifically, the first lens, the fourth lens, and the fifth lens can adopt glass lenses, and the second lens, the third lens, the sixth lens, the seventh lens, and the eighth lens can adopt plastic lenses. Adopting a hybrid glass and plastic structure can improve the thermal stability, effectively reduce the cost, correct the aberration, reduce the volume, and provide an optical lens product with higher cost performance.

[0073] In some embodiments, the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses can be spherical or aspherical lenses. Compared to spherical structures, aspherical structures can effectively reduce the aberrations of the optical system, thereby reducing the number of lenses and their size, and better achieving lens miniaturization. More specifically, in the optical lens provided by this invention, the first, fourth, and fifth lenses can be spherical lenses, while the second, third, sixth, seventh, and eighth lenses can be aspherical lenses.

[0074] In various embodiments of the present invention, when an aspherical lens is used, the shapes of each aspherical surface of the optical lens satisfy the following equations:

[0075]

[0076] 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, and F are the fourth, sixth, eighth, tenth, and twelfth order surface coefficients, respectively.

[0077] 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.

[0078] Example 1

[0079] 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, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter G1, and a protective glass G2.

[0080] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0081] The second lens L2 has negative optical power, its object side S3 is convex, and its image side S4 is concave.

[0082] The third lens L3 has negative optical power, its object side S5 is concave, and its image side S6 is convex.

[0083] The fourth lens L4 has positive optical power, its object side S7 is convex, and its image side S8 is convex.

[0084] The fifth lens L5 has positive optical power, its object side S9 is convex, and its image side S10 is concave.

[0085] The sixth lens L6 has positive optical power, its object-side surface S11 is convex, and its image-side surface is convex.

[0086] The seventh lens L7 has negative optical power, its object side is concave, and its image side S13 is concave near the optical axis.

[0087] The sixth lens L6 and the seventh lens L7 form a cemented lens group, that is, the cementing surface of the image side of the sixth lens L6 and the object side of the seventh lens L7 is S12.

[0088] The eighth lens L8 has positive optical power, its object side S14 is convex near the optical axis, and its image side S15 is convex.

[0089] The object-side surface S16 and the image-side surface S17 of filter G1 are both planar.

[0090] The object side S18 and image side S19 of the protective glass G2 are both flat.

[0091] The imaging plane S20 is a plane.

[0092] The first lens L1, the fourth lens L4, and the fifth lens L5 are glass spherical lenses, while the second lens L2, the third lens L3, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are plastic aspherical lenses.

[0093] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0094] Table 1-1

[0095]

[0096]

[0097] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0098] Table 1-2

[0099] Face number K B C D E F S3 -2.88E+00 -2.58E-02 4.40E-03 -4.13E-04 2.14E-05 -4.68E-07 S4 -7.10E-01 -6.13E-02 5.02E-03 -1.17E-03 1.96E-04 -2.73E-05 S5 1.31E-01 -6.17E-03 5.05E-03 9.53E-04 -3.97E-04 4.14E-05 S6 3.69E-01 -3.86E-03 4.73E-03 8.81E-05 -1.54E-04 1.29E-05 S11 -8.63E-01 -6.33E-03 3.98E-03 -2.47E-03 9.51E-04 -1.45E-04 S12 -4.51E-01 -1.36E-01 4.66E-02 1.78E-03 -6.36E-03 1.33E-03 S13 -7.46E+01 -3.23E-02 9.60E-03 -9.67E-04 -9.25E-05 2.04E-05 S14 -6.74E+00 -7.28E-03 -1.84E-03 5.69E-04 -6.07E-05 -7.97E-07 S15 -9.30E+00 -7.45E-03 2.84E-04 -2.28E-04 6.21E-05 -5.60E-06

[0100] In this embodiment, the field curvature curve, axial aberration curve, and transverse chromatic aberration curve of the optical lens 100 are respectively as follows: Figures 2 to 4 As shown.

[0101] Figure 2 The field curvature curve of Example 1 is shown, which represents the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within -0.08 mm to 0.12 mm, indicating that the optical lens 100 can effectively correct the field curvature.

[0102] Figure 3 The axial aberration curve of Embodiment 1 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the axial aberration offset is controlled within -0.04 mm to 0.02 mm, indicating that the optical lens 100 can effectively correct axial aberration.

[0103] Figure 4 The diagram shows the transverse chromatic aberration curves for Example 1, representing the chromatic aberration of each wavelength relative to the center wavelength (0.54 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the diagram, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2 μm to 6 μm, indicating that the optical lens 100 can effectively correct chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane.

[0104] Example 2

[0105] 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 main difference between this embodiment and Embodiment 1 is that the image side surface S6 of the third lens L3 is concave; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0106] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0107] Table 2-1

[0108]

[0109] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0110] Table 2-2

[0111]

[0112]

[0113] In this embodiment, the field curvature curve, axial aberration curve, and transverse chromatic aberration curve of the optical lens 200 are respectively as follows: Figures 6 to 8 As shown.

[0114] from Figure 6 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.02mm to 0.2mm, indicating that the optical lens 200 can effectively correct the field curvature.

[0115] from Figure 7 As can be seen, the axial aberration offset is controlled within -0.04mm to 0.02mm, indicating that the optical lens 200 can effectively correct axial aberration.

[0116] from Figure 8 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2μm to 6μm, indicating that the optical lens 200 can correct the chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane very well.

[0117] Example 3

[0118] Please see Figure 9 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 optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0119] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0120] Table 3-1

[0121]

[0122]

[0123] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0124] Table 3-2

[0125] Face number K B C D E F S3 -3.19E+00 -2.65E-02 4.48E-03 -4.06E-04 2.00E-05 -4.30E-07 S4 -7.55E-01 -5.97E-02 4.95E-03 -7.26E-04 1.20E-04 -1.76E-05 S5 1.70E-01 -6.98E-03 4.58E-03 9.43E-04 -3.93E-04 4.27E-05 S6 6.44E+00 -4.58E-03 4.28E-03 1.19E-04 -1.76E-04 2.06E-05 S11 -9.82E-01 -6.84E-03 3.18E-03 -2.22E-03 9.49E-04 -1.59E-04 S12 -7.31E-02 -1.64E-01 6.26E-02 1.62E-03 -7.48E-03 1.67E-03 S13 -8.07E+01 -3.42E-02 1.01E-02 -1.05E-03 -6.72E-05 1.81E-05 S14 -7.40E+00 -5.69E-03 -2.38E-03 5.89E-04 -4.84E-05 1.28E-07 S15 -1.05E+01 -8.11E-03 4.60E-04 -2.78E-04 6.87E-05 -5.01E-06

[0126] In this embodiment, the field curvature curve, axial aberration curve, and transverse chromatic aberration curve of the optical lens 300 are respectively as follows: Figures 10 to 12 As shown.

[0127] from Figure 10 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.04mm to 0.12mm, indicating that the optical lens 300 can effectively correct field curvature.

[0128] from Figure 11 As can be seen, the axial aberration offset is controlled within -0.04mm to 0.02mm, indicating that the optical lens 300 can effectively correct axial aberration.

[0129] from Figure 12 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2μm to 5μm, indicating that the optical lens 300 can correct the chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane very well.

[0130] Please refer to Table 4 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, principal ray incident angle CRA at the maximum image height, true image height IH corresponding to the maximum field of view, maximum field of view FOV, entrance pupil diameter EPD, 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.

[0131] Table 4

[0132]

[0133]

[0134]

[0135] In summary, the optical lens provided by the present invention has eight lenses with 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 large aperture, large field of view, and large image plane.

[0136] 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.

[0137] 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 having eight pieces of lenses with optical power, characterized in that, In order from the object side to the imaging surface along the optical axis, comprises successively: a first lens with negative refractive power, the object side surface of which is convex, and the image side surface of which is concave; a second lens with negative refractive power, the object side surface of which is convex, and the image side surface of which is concave; a third lens with negative refractive power, the object side surface of which is concave; a fourth lens with positive refractive power, the object side surface of which is convex, and the image side surface of which is convex; a fifth lens with positive refractive power, the object side surface of which is convex, and the image side surface of which is concave; a sixth lens with positive refractive power, the object side surface of which is convex, and the image side surface of which is convex; a seventh lens with negative refractive power, the object side surface of which is concave, and the image side surface of which is concave near the optical axis; an eighth lens with positive refractive power, the object side surface of which is convex near the optical axis, and the image side surface of which is convex; wherein the real 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: 1.14 < (IH / 2) / (f×θ) < 1.19; the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 11 < f5 / f < 16.

2. The optical lens of claim 1, wherein, The optical lens satisfies at least one of the following condition formulas: the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 13 < TTL / f < 15.5; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 3.3 < TTL / IH < 3.

8.

3. The optical lens of claim 1, wherein, The optical lens satisfies at least one of the following condition formulas: the real image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 6 < IH / EPD < 7; the real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 4 < IH / f < 4.

2.

4. The optical lens of claim 1, wherein, The optical lens satisfies at least one of the following condition formulas: the total optical length TTL of the optical lens, the real image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.06° < TTL / (IH / 2) / (FOV / 2) < 0.08°; the object side surface half light entrance radius d1 of the first lens, the real image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: -0.54 < d1 / (IH / 2) / tan(FOV / 2) < -0.

4.

5. The optical lens of claim 1, wherein, The optical lens satisfies at least one of the following condition formulas: the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -8.5 < f1 / f < -5; the object side surface curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: 8.5 < R1 / f < 9.5; the image side surface curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: 2.5 < R2 / f < 4.

6. The optical lens of claim 1, wherein, The optical lens satisfies at least one of the following conditional expressions, a focal length f2 of the second lens and an effective focal length f of the optical lens satisfy: -4.4 < f2 / f < -2.8; a curvature radius R3 of an object side surface of the second lens and the effective focal length f of the optical lens satisfy: 2.4 < R3 / f < 4.2; a curvature radius R4 of an image side surface of the second lens and the effective focal length f of the optical lens satisfy: 0.95 < R4 / f < 1.

5.

7. The optical lens of claim 1, wherein, The optical lens satisfies at least one of the following conditional expressions, a focal length f3 of the third lens and an effective focal length f of the optical lens satisfy: -4.5 < f3 / f < -3.3; a curvature radius R5 of an object side surface of the third lens and the effective focal length f of the optical lens satisfy: -4.3 < R5 / f < -1.9; the curvature radius R4 of the image side surface of the second lens and the curvature radius R5 of the object side surface of the third lens satisfy: -0.52 < R4 / R5 < -0.

32.

8. The optical lens of claim 1, wherein, The optical lens satisfies at least one of the following conditional expressions, a combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and an effective focal length f of the optical lens satisfy: -4 < f1234 / f < -2; a combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 3 < f5678 / f < 3.5; a combined focal length f67 of the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 9 < f67 / f < 17; the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -1.2 < f1234 / f5678 < -0.7; the combined focal length f67 of the sixth lens and the seventh lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 3 < f67 / f5678 < 5.

9. The optical lens of claim 1, wherein, The optical lens satisfies at least one of the following conditional expressions, a focal length f2 of the second lens and a focal length f3 of the third lens satisfy: 0.7 < f2 / f3 < 1.3; a curvature radius R4 of an image side surface of the second lens and a curvature radius R5 of an object side surface of the third lens satisfy: -3.1 < (R4-R5) / (R4+R5) < -1.

9.

10. The optical lens of claim 1, wherein, The optical lens satisfies at least one of the following conditional expressions, a focal length f4 of the fourth lens and a focal length f5 of the fifth lens satisfy: 0.22 < f4 / f5 < 0.32; a curvature radius R7 of an object side surface of the fourth lens and an effective focal length f of the optical lens satisfy: 3 < R7 / f < 6.5; a curvature radius R8 of an image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -1200 < R8 / f < -7; a curvature radius R9 of an object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 2.1 < R9 / f < 4.2; a curvature radius R10 of an image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 2 < R10 / f < 5.5.

Images