Optical lens

Abstract

The application provides an optical lens which is composed of eight lenses and sequentially comprises, along an optical axis from an object side to an imaging surface, a first lens with negative optical power, the object side of which is a convex surface and the image side of which is a concave surface; a second lens with negative optical power, the object side of which is a concave surface and the image side of which is a convex surface; a third lens with positive optical power, the object side of which is a convex surface and the image side of which is a concave surface; a fourth lens with negative optical power, the object side of which is a convex surface and the image side of which is a concave surface; a fifth lens with positive optical power, the object side of which is a convex surface and the image side of which is a convex surface; a sixth lens with negative optical power; a seventh lens with positive optical power; and an eighth lens with negative optical power, the object side of which is a convex surface near the optical axis and the image side of which is a concave surface near the optical axis. The optical lens provided by the application can improve the imaging quality of the optical lens and make the lens have one or more advantages such as a large field of view, a large aperture, high imaging quality 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] Law enforcement recorders are primarily used to digitally record the situation at the scene during law enforcement, such as taking videos, photos, and audio recordings, so that effective on-site video data can be provided afterward. During on-site law enforcement, law enforcement officers need to record a wide range of clear images; however, the lenses of law enforcement recorders on the market either record unclear images or have too small a field of view, which prevents them from recording too much footage.

[0003] Therefore, how to ensure high imaging quality in law enforcement recorder lenses is a problem that urgently needs to be solved. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide an optical lens with the advantage of excellent image quality.

[0005] The technical solution adopted in this invention is as follows:

[0006] An optical lens, comprising eight lenses, arranged sequentially along the optical axis from the object side to the imaging plane:

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

[0008] A second lens with negative optical power has a concave object side and a convex image side.

[0009] A third lens with positive optical power has a convex object-side surface and a concave image-side surface.

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

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

[0012] A sixth lens with negative optical power;

[0013] A seventh lens with positive optical power;

[0014] The eighth lens with negative optical power has an object-side surface that is convex near the optical axis and an image-side surface that is concave near the optical axis.

[0015] Among them, the curvature radius R3 of the object side surface of the second lens and the curvature radius R4 of the image side surface of the second lens satisfy: -0.7 < (R3 - R4) / (R3 + R4) < 0; the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: -1 < (R5 - R6) / (R5 + R6) < -0.4.

[0016] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5 < TTL / f < 8.5; 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: 2.2 < TTL / IH < 3.7.

[0017] Further preferably, the maximum field angle FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 65° < FOV / FNO < 85°; 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: 4 < IH / EPD < 5.2.

[0018] Further preferably, 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: 2 < IH / f < 2.6; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.6 < BFL / f < 0.8.

[0019] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -3 < f1 / f < -1.5, the effective focal length f of the optical lens and the curvature radius R1 of the object side surface of the first lens satisfy: 4.3 < R1 / f < 32, the effective focal length f of the optical lens and the curvature radius R2 of the image side surface of the first lens satisfy: 0.9 < R2 / f < 2.1.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -700 < f2 / f < -4.2, the effective focal length f of the optical lens and the curvature radius R3 of the object side surface of the second lens satisfy: -3.2 < R3 / f < -2.1, the effective focal length f of the optical lens and the curvature radius R4 of the image side surface of the second lens satisfy: -11 < R4 / f < -3.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.8 < f3 / f < 2.4, the effective focal length f of the optical lens and the curvature radius R5 of the object side surface of the third lens satisfy: 0.8 < R5 / f < 1.5, the effective focal length f of the optical lens and the curvature radius R6 of the image side surface of the third lens satisfy: 2.9 < R6 / f < 80.

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1 < f5 / f < 1.6, and 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 < R9 / f < 5.5; 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: -1.7 < R10 / f < -1.

[0023] Further preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -19 < f8 / f < -3.5, and 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: 2.4 < R15 / f < 39; 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: 1.3 < R16 / f < 3.3.

[0024] Further preferably, the combined focal length f123 of the first lens, the second lens and the third lens and the effective focal length f of the optical lens satisfy: 1.2 < f123 / f < 21; the combined focal length f45678 of 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: 1.8 < f45678 / f < 7.

[0025] Compared with the prior art, the optical lens provided by the present invention uses eight lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power distributions, it can improve the imaging quality of the optical lens, reduce aberration, and improve the imaging quality of the optical lens, making the lens have one or more advantages such as a large viewing angle, a large aperture, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 2 is a graph of F-Tan(Theta) distortion of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 3 is a graph of axial aberration of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 4 is a graph of lateral chromatic aberration of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 5 This is an MTF curve of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 6 This is a relative illumination curve of the optical lens in Embodiment 1 of the present invention.

[0033] Figure 7 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0034] Figure 8 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0035] Figure 9 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0036] Figure 10 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0037] Figure 11 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0038] Figure 12 This is a relative illumination curve of the optical lens in Embodiment 2 of the present invention.

[0039] Figure 13 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0040] Figure 14 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0041] Figure 15 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0042] Figure 16 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0043] Figure 17 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0044] Figure 18 This is a relative illumination curve of the optical lens in Embodiment 3 of the present invention.

[0045] Figure 19 This is a schematic diagram of the optical lens structure in Embodiment 4 of the present invention.

[0046] Figure 20 This is the F-Tan (Theta) distortion curve of the optical lens in Embodiment 4 of the present invention.

[0047] Figure 21 This is an axial aberration curve of the optical lens in Embodiment 4 of the present invention.

[0048] Figure 22 This is a chromatic aberration curve of the optical lens in Embodiment 4 of the present invention.

[0049] Figure 23 This is the MTF curve of the optical lens in Embodiment 4 of the present invention.

[0050] Figure 24 This is a relative illumination curve of the optical lens in Embodiment 4 of the present invention.

[0051] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] The optical lens provided in this embodiment of the invention consists of eight lenses, which are 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.

[0060] In some embodiments, the first lens may have negative optical power, with a convex object-side surface and a concave image-side surface. The second lens may have negative optical power, with a concave object-side surface and a convex image-side surface. The third lens may have positive optical power, with a convex object-side surface and a concave image-side surface. The fourth lens may have negative optical power, with a convex object-side surface and a concave image-side surface. The fifth lens may have positive optical power, with a convex object-side surface and a convex image-side surface. The sixth lens may have negative optical power, with either a concave or convex object-side surface and either a concave or convex image-side surface. The seventh lens may have positive optical power, with either a concave or convex object-side surface and either a concave or convex image-side surface. The eighth lens may have negative optical power, with a convex object-side surface near the optical axis and a concave image-side surface near the optical axis.

[0061] In some embodiments, the optical lens may also include an aperture stop, which may be located between the third and fourth lenses. It is understood that the aperture stop can be used to limit the amount of light entering the lens to change the brightness of the image.

[0062] In some embodiments, the optical lens may further include a filter, which may be disposed between the eighth lens and the imaging surface. The filter is used to filter out interfering light and prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0063] In some embodiments, the sixth lens and the seventh lens may be glued together to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0064] 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: -0.7 < (R3 - R4) / (R3 + R4) < 0; the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -1 < (R5 - R6) / (R5 + R6) < -0.4. Satisfying the above ranges can correct the aberration of the optical lens, ensure the smooth trend of the light passing through the second lens and the third lens, reduce the tolerance sensitivity of the optical lens, and is conducive to the smooth entry of light into the rear lens. More specifically, -0.59 < (R3 - R4) / (R3 + R4) < -0.1; -0.97 < (R5 - R6) / (R5 + R6) < -0.53.

[0065] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5 < TTL / f < 8.5; 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: 2.2 < TTL / IH < 3.7. Satisfying the above ranges, by reasonably controlling the total length, focal length, and image height of the optical lens, it helps the optical lens to achieve the balance between the total length and the volume, and is conducive to improving the structural stability of the optical lens. More specifically, 5.52 < TTL / f < 8.08, 2.48 < TTL / IH < 3.46.

[0066] In some embodiments, the maximum field angle FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 65° < FOV / FNO < 85°; 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: 4 < IH / EPD < 5.2. Satisfying the above ranges helps to achieve the characteristics of a large field angle and a large aperture of the optical lens, is conducive to increasing the light transmission amount, and improving the relative illumination. More specifically, 71.21° < FOV / FNO < 80.1°, 4.35 < IH / EPD < 4.83.

[0067] 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: 2 < IH / f < 2.6; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.6 < BFL / f < 0.8. Meeting the above ranges can reasonably control the image height, focal length, and back focal length of the optical lens. Under the condition of a fixed focal length, it can endow the optical lens with the characteristics of a large target surface and a long back focal length. The characteristic of the large target surface helps to improve the imaging quality of the optical lens, and the characteristic of the long back focal length can meet the layout requirements of the backend chip and reduce the assembly and processing difficulty. More specifically, 2.17 < IH / f < 2.42, 0.62 < BFL / f < 0.74.

[0068] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -3 < f1 / f < -1.5, the effective focal length f of the optical lens and the object-side curvature radius R1 of the first lens satisfy: 4.3 < R1 / f < 32, and the effective focal length f of the optical lens and the image-side curvature radius R2 of the first lens satisfy: 0.9 < R2 / f < 2.1. Meeting the above ranges enables the first lens to have an appropriate negative optical power and surface shape, which helps to collect as much light with a large field angle as possible into the optical lens, obtain more picture information, and control the trend of the large-angle light at the edge, thereby improving the imaging quality of the optical lens. More specifically, -2.75 < f1 / f < -1.69, 4.72 < R1 / f < 29.82, 1.02 < R2 / f < 1.99.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -700 < f2 / f < -4.2, the effective focal length f of the optical lens and the object-side curvature radius R3 of the second lens satisfy: -3.2 < R3 / f < -2.1, and the effective focal length f of the optical lens and the image-side curvature radius R4 of the second lens satisfy: -11 < R4 / f < -3. Meeting the above ranges enables the second lens to have an appropriate negative optical power and a reasonable surface shape combination, which helps the divergent light to enter the subsequent lenses smoothly and makes the light trend stable. More specifically, -669.84 < f2 / f < -4.6, -2.93 < R3 / f < -2.36, -10.03 < R4 / f < -3.23.

[0070] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.8 < f3 / f < 2.4, the effective focal length f of the optical lens and the object-side curvature radius R5 of the third lens satisfy: 0.8 < R5 / f < 1.5, and the effective focal length f of the optical lens and the image-side curvature radius R6 of the third lens satisfy: 2.9 < R6 / f < 80. Meeting the above ranges gives the third lens an appropriate positive optical power and surface shape, which helps converge light, and the lens shape is gentle, which is beneficial for reducing volume and cost. More specifically, 2.04 < f3 / f < 2.25; 0.92 < R5 / f < 1.36; 3.15 < R6 / f < 74.71.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1 < f5 / f < 1.6, the object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: 2 < R9 / f < 5.5; the image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -1.7 < R10 / f < -1. Meeting the above ranges, by reasonably controlling the focal length ratio and surface shape of the fifth lens, it helps to smooth the light trend of the front lens, correct the aberration generated by the front lens, and improve the imaging quality. More specifically, 1.16 < f5 / f < 1.48; 2.25 < R9 / f < 4.98; -1.57 < R10 / f < -1.13.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -19 < f8 / f < -3.5, the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 2.4 < R15 / f < 39; the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.3 < R16 / f < 3.3. Meeting the above ranges, by reasonably controlling the focal length ratio and surface shape of the eighth lens, it helps to control the light trend to the image plane smoothly, obtain the characteristics of a large target surface, and ensure a high resolution ability on the basis of eliminating ghost images, improving the imaging quality of the optical lens. More specifically, -17.77 < f8 / f < -3.7; 2.6 < R15 / f < 35.57; 1.47 < R16 / f < 2.99.

[0073] In some embodiments, the combined focal length f123 of the first lens, the second lens, and the third lens and the effective focal length f of the optical lens satisfy: 1.2 < f123 / f < 21; the combined focal length f45678 of 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: 1.8 < f45678 / f < 7; the combined focal length f123 of the first lens, the second lens, and the third lens and the combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy: 0.1 < f123 / f45678 < 11. Satisfying the above ranges and reasonably setting the focal lengths of the lens groups before and after the aperture is conducive to balancing the distortion and astigmatism generated by the optical lens and improving the imaging quality of the optical lens. More specifically, 1.34 < f123 / f < 19.94; 1.86 < f45678 / f < 6.34; 0.2 < f123 / f45678 < 10.12.

[0074] In some embodiments, the effective focal length f of the optical lens, the maximum field angle FOV, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 60° < f × FOV / IH < 75°. Satisfying the above range and reasonably restricting the relationship between the focal length, the field angle, and the image height of the optical lens is conducive to achieving the balance between the large field angle and the large target surface imaging of the optical lens. More specifically, 64.05° < f × FOV / IH < 71.57°.

[0075] In some embodiments, the half-aperture d1 of the object side of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.3 < d1 / (IH / 2) / tan(FOV / 2) < 0.7. Satisfying the above range can have a small front aperture while satisfying the optical lens with a large field angle and a large image surface. More specifically, 0.36 < d1 / (IH / 2) / tan(FOV / 2) < 0.62.

[0076] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -4.2 < f4 / f < -2.4. Satisfying the above range and reasonably controlling the focal length ratio of the fourth lens helps to collect the light rays emitted by the front-end lens and enables the collected light rays to smoothly enter the subsequent lenses, and is conducive to improving the resolution ability of the optical lens. More specifically, -3.89 < f4 / f < -2.67.

[0077] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.9 < f6 / f < -0.9. By reasonably setting the focal length of the sixth lens within the above range, the aberration of the marginal field of view can be effectively improved, and the overall imaging quality of the optical lens can be enhanced. More specifically, -1.77 < f6 / f < -1.

[0078] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.1 < f7 / f < 2.6. By reasonably setting the focal length of the seventh lens within the above range, better correction of the chromatic aberration of the system can be achieved in cooperation with the sixth lens, and the overall imaging quality can be improved. More specifically, 1.2 < f7 / f < 2.4.

[0079] In some embodiments, the optical lens satisfies the conditional expressions: 2.3 mm < f < 3 mm, 1.1 mm < EPD < 1.5 mm, 15 mm < TTL < 21 mm, 1.8 < FNO < 2.2, 16° < CRA < 22°, 1.6 mm < BFL < 2.1 mm, 140° < FOV < 170°, 5.5 mm < IH < 7 mm; where f represents the effective focal length of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, FNO represents the aperture value of the optical lens, CRA represents the principal ray incident angle at the maximum image height of the optical lens, BFL represents the back focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, and IH represents the true image height corresponding to the maximum field of view angle of the optical lens. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least the characteristics of a large field of view angle, a large aperture, and high imaging quality. More specifically, 2.47 mm < f < 2.8 mm, 1.23 mm < EPD < 1.37 mm, 15.42 mm < TTL < 20.1 mm, 1.9 < FNO < 2.06, 16.94° < CRA < 21.9°, 1.67 mm < BFL < 2.06 mm, 145° < FOV < 161°, 5.79 mm < IH < 6.46 mm.

[0080] 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 first lens, the second lens, the fifth lens, the sixth lens, and the seventh lens in the optical lens provided by the present invention are glass lenses, and the third lens, the fourth lens, and the eighth lens are plastic lenses.

[0081] 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 aberrations in the optical system, thereby reducing the number of lenses and their size, and better achieving lens miniaturization. More specifically, the third, fourth, fifth, and eighth lenses of this invention are aspherical lenses, while the first, second, sixth, and seventh lenses are spherical lenses.

[0082] 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:

[0083]

[0084] 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.

[0085] 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.

[0086] Example 1

[0087] Please see Figure 1 The diagram shown is a schematic diagram of the structure of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens includes, in sequence along the optical axis from the object side to the imaging plane: a first lens L1, a second lens L2, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0088] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0089] The second lens L2 has negative optical power, its object side S3 is concave, and its image side S4 is convex.

[0090] The third lens L3 has positive optical power, its object side S5 is convex, and its image side S6 is concave.

[0091] The fourth lens L4 has negative optical power, its object side S7 is convex, and its image side S8 is concave.

[0092] The fifth lens L5 has positive optical power, its object side S9 is convex, and its image side S10 is convex.

[0093] The sixth lens L6 has negative optical power, its object side S11 is convex, and its image side is concave.

[0094] The seventh lens L7 has positive optical power, its object side is convex, and its image side S13 is convex.

[0095] The sixth lens L6 and the seventh lens L7 form a cemented lens group with positive optical power, that is, the cemented surface of the image side of the sixth lens L6 and the object side of the seventh lens L7 is S13.

[0096] The eighth lens L8 has negative optical power. Its object side S14 is convex near the optical axis, and its image side S15 is concave near the optical axis.

[0097] The object-side surface S16 and the image-side surface S17 of filter G1 are both planar.

[0098] The imaging plane S18 is a plane.

[0099] The first lens L1, the second lens L2, the sixth lens L6 and the seventh lens L7 are all glass spherical lenses, the fifth lens L5 is a glass aspherical lens, and the third lens L3, the fourth lens L4 and the eighth lens L8 are all plastic aspherical lenses.

[0100] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0101] Table 1-1

[0102]

[0103] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0104] Table 1-2

[0105] Face number K B C D E F G H S5 4.95E-01 8.46E-03 -2.56E-04 1.95E-03 -1.01E-03 5.40E-04 -1.64E-04 2.42E-05 S6 -2.00E+02 2.49E-02 -1.38E-02 1.75E-02 -5.28E-03 -4.53E-03 3.78E-03 -7.87E-04 S7 -5.11E+01 1.78E-03 -1.34E-02 4.72E-03 -1.53E-03 -4.00E-04 6.53E-05 4.02E-06 S8 -7.76E+00 -3.09E-03 2.69E-03 -1.59E-03 -1.85E-04 7.16E-05 2.68E-05 -6.26E-06 S9 -1.46E+02 -6.10E-03 4.82E-04 1.03E-04 2.85E-05 -1.33E-05 0.00E+00 0.00E+00 S10 -1.33E-01 -7.87E-03 -4.35E-04 -3.14E-05 -4.78E-05 5.06E-06 0.00E+00 0.00E+00 S14 1.91E+01 -1.67E-02 -1.12E-04 7.35E-06 2.53E-05 -7.54E-06 9.97E-07 -6.17E-08 S15 -3.26E+00 -1.33E-02 3.06E-04 2.03E-05 -3.11E-06 -2.93E-07 6.04E-08 -2.71E-09

[0106] Figure 2 The F-Tan (Theta) distortion curve of the optical lens 100 in this embodiment is shown, which represents the distortion at different field-of-view angles on the imaging plane. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the distortion value changes relatively smoothly as the field of view increases, indicating that the optical lens 100 can correct distortion well.

[0107] Figure 3 The diagram shows the axial aberration curve of the optical lens 100 in this embodiment, 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 0.04 mm, indicating that the optical lens 100 can correct axial aberration well.

[0108] Figure 4 The diagram shows the transverse chromatic aberration curve of the optical lens 100 in this embodiment. It represents the chromatic aberration of each wavelength relative to the center wavelength (0.555 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 figure, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within 0–4 μm, indicating that the optical lens 100 can effectively correct chromatic aberration.

[0109] Figure 5 The modulation transfer function (MTF) curve of the optical lens 100 in this embodiment is shown, which represents the lens imaging modulation at different spatial frequencies in each field of view. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of this embodiment is above 0.38 throughout the entire field of view. 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.

[0110] Figure 6 The relative illumination curve of the optical lens 100 in this embodiment is shown, which represents the relative illumination value at different field-of-view angles on the imaging plane. The horizontal axis represents the half-field-of-view angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 80% at the maximum half-field-of-view angle, indicating that the optical lens has good relative illumination.

[0111] Example 2

[0112] Please see Figure 7 The figure shown is 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 optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0113] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0114] Table 2-1

[0115]

[0116]

[0117] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0118] Table 2-2

[0119] Face number K B C D E F G H S5 4.12E-01 8.24E-03 -3.75E-04 1.90E-03 -1.02E-03 5.37E-04 -1.64E-04 2.48E-05 S6 2.00E+02 2.47E-02 -1.38E-02 1.76E-02 -5.28E-03 -4.54E-03 3.78E-03 -7.75E-04 S7 -4.87E+01 2.10E-03 -1.34E-02 4.73E-03 -1.49E-03 -3.57E-04 8.88E-05 1.01E-05 S8 -7.77E+00 -2.99E-03 2.72E-03 -1.57E-03 -1.77E-04 7.26E-05 2.66E-05 -6.65E-06 S9 -1.45E+02 -5.91E-03 4.96E-04 8.91E-05 2.44E-05 -1.42E-05 0.00E+00 0.00E+00 S10 -1.05E-01 -7.92E-03 -5.38E-04 -5.32E-05 -5.08E-05 5.02E-06 0.00E+00 0.00E+00 S14 2.46E+01 -1.33E-02 9.99E-05 1.53E-07 2.22E-05 -7.82E-06 1.02E-06 -4.90E-08 S15 -1.61E+00 -1.32E-02 2.72E-04 1.80E-05 -3.15E-06 -2.83E-07 6.15E-08 -2.83E-09

[0120] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination diagram of the optical lens 200 are respectively as follows: Figures 8 to 12 As shown.

[0121] from Figure 8 As can be seen, the distortion value changes relatively smoothly as the field of view increases, indicating that the optical lens 200 can correct distortion well.

[0122] from Figure 9 As can be seen, the axial aberration offset is controlled within -0.04mm to 0.04mm, indicating that the optical lens 200 can effectively correct axial aberration.

[0123] from Figure 10 As can be seen, the chromatic aberration of the longest and shortest wavelengths is controlled within -1μm to 3μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0124] from Figure 11 As can be seen, the MTF value of this embodiment is above 0.48 throughout the entire field of view. The MTF curve decreases smoothly and evenly from the center to the edge of the field of view, demonstrating good imaging quality and good detail resolution in both low and high frequency conditions.

[0125] from Figure 12 As can be seen, the relative illumination value of the optical lens is still greater than 90% at the maximum half field of view, indicating that the optical lens 200 has good relative illumination.

[0126] Example 3

[0127] Please see Figure 13 The diagram shows a schematic 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 sixth lens L6 and the seventh lens L7 form a cemented lens group with negative optical power; the object side S11 of the sixth lens L6 is concave; the image side of the sixth lens L6 is convex; the object side of the seventh lens L7 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0128] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0129] Table 3-1

[0130]

[0131] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0132] Table 3-2

[0133] Face number K B C D E F G H S5 -1.31E-01 2.07E-03 1.74E-04 1.18E-03 -1.10E-03 5.48E-04 -1.29E-04 1.24E-05 S6 3.00E+01 9.44E-03 -1.25E-02 1.43E-02 -4.53E-03 -4.30E-03 3.63E-03 -7.89E-04 S7 -4.01E+02 -2.96E-04 -1.21E-02 4.13E-03 -1.88E-03 -2.21E-04 2.98E-04 -1.25E-04 S8 -1.25E+01 -3.04E-03 3.26E-03 -1.12E-03 -3.46E-05 -4.58E-06 -8.48E-06 3.42E-06 S9 -1.55E+01 -7.62E-03 2.58E-05 1.78E-04 -2.89E-05 -3.18E-06 0.00E+00 0.00E+00 S10 8.45E-01 -1.15E-02 -7.78E-04 1.60E-04 -6.54E-05 6.17E-06 0.00E+00 0.00E+00 S14 -4.28E+10 -1.95E-02 6.81E-04 2.58E-05 1.76E-05 -6.72E-06 1.06E-06 -6.74E-08 S15 -1.09E+01 -1.49E-02 6.17E-04 1.82E-05 -4.92E-06 -1.86E-07 8.85E-08 -5.67E-09

[0134] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination diagram of the optical lens 300 are respectively as follows: Figures 14 to 18 As shown.

[0135] from Figure 14 As can be seen, the distortion value changes relatively smoothly as the field of view increases, indicating that the optical lens 300 can correct distortion well.

[0136] from Figure 15 As can be seen, the axial aberration offset is controlled within -0.04mm to 0.04mm, indicating that the optical lens 300 can correct axial aberration well.

[0137] from Figure 16 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -1μm to 4μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0138] from Figure 17 As can be seen, the MTF value of this embodiment is above 0.5 throughout the entire field of view. The MTF curve decreases smoothly and evenly from the center to the edge of the field of view, demonstrating good imaging quality and good detail resolution in both low and high frequency conditions.

[0139] from Figure 18 As can be seen, the relative illumination value of the optical lens is still greater than 95% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0140] Example 4

[0141] Please see Figure 19The 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 sixth lens L6 and the seventh lens L7 form a cemented lens group with negative optical power; the object side S11 of the sixth lens L6 is concave; the image side S13 of the seventh lens L7 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0142] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0143] Table 4-1

[0144]

[0145]

[0146] The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0147] Table 4-2

[0148] Face number K B C D E F G H S5 -1.48E-01 1.80E-03 4.24E-04 1.15E-03 -1.12E-03 5.37E-04 -1.20E-04 1.09E-05 S6 2.83E+01 1.06E-02 -1.35E-02 1.51E-02 -4.32E-03 -4.38E-03 3.46E-03 -7.10E-04 S7 -1.55E+04 -7.66E-03 -1.23E-02 4.54E-03 -1.51E-03 -2.89E-04 1.30E-04 -2.83E-05 S8 -8.07E+00 -3.71E-03 3.49E-03 -1.17E-03 -1.57E-04 1.76E-05 1.36E-05 -2.92E-06 S9 -2.38E+01 -1.93E-03 1.14E-03 -3.73E-05 -3.64E-05 -1.12E-05 0.00E+00 0.00E+00 S10 2.18E-01 -6.41E-03 3.09E-04 -8.47E-05 -6.76E-05 1.70E-05 0.00E+00 0.00E+00 S14 -3.30E+01 -2.09E-02 1.79E-04 -4.53E-05 1.46E-05 -7.52E-06 9.58E-07 -1.30E-07 S15 -1.95E+01 -1.96E-02 2.53E-04 -2.87E-06 -5.33E-06 -2.16E-07 6.62E-08 -1.50E-08

[0149] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination diagram of the optical lens 400 are respectively as follows: Figures 20 to 24 As shown.

[0150] from Figure 20 As can be seen, the distortion value changes relatively smoothly as the field of view increases, indicating that the optical lens 400 can correct distortion well.

[0151] from Figure 21 As can be seen, the axial aberration offset is controlled within -0.04mm to 0.04mm, indicating that the optical lens 400 can correct axial aberration well.

[0152] from Figure 22 As can be seen, the chromatic aberration of the longest and shortest wavelengths is controlled within -1μm to 4μm, indicating that the optical lens 400 can correct chromatic aberration well.

[0153] from Figure 23 As can be seen, the MTF value of this embodiment is above 0.5 throughout the entire field of view. The MTF curve decreases smoothly and evenly from the center to the edge of the field of view, demonstrating good imaging quality and good detail resolution in both low and high frequency conditions.

[0154] from Figure 24As can be seen, the relative illumination value of the optical lens is still greater than 80% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0155] Please refer to Table 5 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture value FNO, true image height IH corresponding to the maximum field of view, principal ray incident angle CRA at the maximum image height, maximum field of view FOV, and the values ​​corresponding to each conditional expression in each embodiment.

[0156] Table 5

[0157]

[0158]

[0159] In summary, the optical lens provided by the present invention employs 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 a large field of view, a large aperture, and high imaging quality.

[0160] 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.

[0161] 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, characterized in that, It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with a negative optical power, whose object side is convex and whose image side is concave; A second lens with a negative optical power, whose object side is concave and whose image side is convex; A third lens with a positive optical power, whose object side is convex and whose image side is concave; A fourth lens with a negative optical power, whose object side is convex and whose image side is concave; A fifth lens with a positive optical power, whose object side is convex and whose image side is convex; A sixth lens with a negative optical power; A seventh lens with a positive optical power; An eighth lens with a negative optical power, whose object side is convex near the optical axis and whose image side is concave near the optical axis; Wherein, 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: -0.7 < (R3 - R4) / (R3 + R4) < 0; the curvature radius R5 of the object side of the third lens and the curvature radius R6 of the image side of the third lens satisfy: -1 < (R5 - R6) / (R5 + R6) < -0.4; 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: 2.2 < TTL / IH < 3.7; 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: 4 < IH / EPD < 5.

2.

2. The optical lens according to claim 1, characterized in that, The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5 < TTL / f < 8.5; 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: 2.48 < TTL / IH < 3.46; 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: -0.59 < (R3 - R4) / (R3 + R4) < -0.1; the curvature radius R5 of the object side of the third lens and the curvature radius R6 of the image side of the third lens satisfy: -0.97 < (R5 - R6) / (R5 + R6) < -0.

53.

3. The optical lens according to claim 1, characterized in that, The maximum field angle FOV of the optical lens and the f-number FNO of the optical lens satisfy: 65° < FOV / FNO < 85°; 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: 4.35 < IH / EPD < 4.

83.

4. The optical lens according to claim 1, characterized in that, 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: 2 < IH / f < 2.6; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.6 < BFL / f < 0.

8.

5. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -3 < f1 / f < -1.5, the effective focal length f of the optical lens and the curvature radius R1 of the object side of the first lens satisfy: 4.3 < R1 / f < 32, the effective focal length f of the optical lens and the curvature radius R2 of the image side of the first lens satisfy: 0.9 < R2 / f < 2.

1.

6. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -700 < f2 / f < -4.

2. The effective focal length f of the optical lens and the object-side curvature radius R3 of the second lens satisfy: -3.2 < R3 / f < -2.

1. The effective focal length f of the optical lens and the image-side curvature radius R4 of the second lens satisfy: -11 < R4 / f < -3.

7. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.8 < f3 / f < 2.

4. The effective focal length f of the optical lens and the object-side curvature radius R5 of the third lens satisfy: 0.8 < R5 / f < 1.

5. The effective focal length f of the optical lens and the image-side curvature radius R6 of the third lens satisfy: 2.9 < R6 / f < 80.

8. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1 < f5 / f < 1.

6. The object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: 2 < R9 / f < 5.

5. The image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -1.7 < R10 / f < -1.

9. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -19 < f8 / f < -3.

5. The object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 2.4 < R15 / f < 39. The image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.3 < R16 / f < 3.

3.

10. The optical lens according to claim 1, characterized in that, The combined focal length f123 of the first lens, the second lens and the third lens and the effective focal length f of the optical lens satisfy: 1.2 < f123 / f < 21. The combined focal length f45678 of 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: 1.8 < f45678 / f < 7.

Images