Optical lens

Abstract

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

Description

Technical Field

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

[0002] Body cameras are primarily used to digitally record on-site law enforcement situations, such as video, photography, and audio recording, so that effective on-site image data can be provided later. During on-site law enforcement, law enforcement officers need to record a wide range of clear images. However, the lenses of existing body cameras on the market either record unclear images or have a narrow field of view, which prevents them from recording a large amount of footage.

[0003] Therefore, how to make the lens of the body camera meet high imaging quality is an urgent problem to be solved. Summary of the Invention

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

[0005] The technical solution adopted in the present invention is: An optical lens, consisting of eight lenses, including the following elements from the object side to the imaging surface along the optical axis: The first lens has a negative optical power, its object-side surface is convex and its image-side surface is concave; a second lens having negative optical power, wherein the object-side surface and the image-side surface are concave; a third lens element having positive optical power, whose object-side surface is convex and whose image-side surface is convex; a fourth lens element having negative optical power, whose object-side surface is convex and whose image-side surface is concave; a fifth lens having positive refractive power; a sixth lens element having negative optical power, whose object-side surface is convex and whose image-side surface is concave; a seventh lens element having positive refractive power, whose object-side surface and image-side surface are convex; an eighth lens element having negative optical power, whose object-side surface is convex near the optical axis and whose image-side surface is concave near the optical axis; Among them, the object side curvature radius R5 of the third lens and the image side curvature radius R6 of the third lens satisfy: 0<(R5+R6) / (R5-R6)<0.4, and the object side curvature radius R11 of the sixth lens and the image side curvature radius R12 of the sixth lens satisfy: 0.6<(R11-R12) / (R11+R12)<1.

[0006] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6 < TTL / f < 9; 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: 2.3 < TTL / IH < 3.6.

[0007] Further preferably, the maximum field angle FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 65° < FOV / FNO < 90°; 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: 4.1 < IH / EPD < 5.8.

[0008] 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: 2.3 < IH / f < 2.9; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.7 < BFL / f < 1.1.

[0009] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2 < f1 / f < -1.4, the effective focal length f of the optical lens and the object side curvature radius R1 of the first lens satisfy: 2.7 < R1 / f < 6, 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 < 1.3; the object side curvature radius R1 of the first lens and the image side curvature radius R2 of the first lens satisfy: 0.4 < (R1 - R2) / (R1 + R2) < 0.7.

[0010] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.1 < f3 / f < 1.4, the effective focal length f of the optical lens and the object side curvature radius R5 of the third lens satisfy: 1.4 < R5 / f < 2.6, the effective focal length f of the optical lens and the image side curvature radius R6 of the third lens satisfy: -1.5 < R6 / f < -1.1.

[0011] Further preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.7 < f6 / f < -1.2, the effective focal length f of the optical lens and the object side curvature radius R11 of the sixth lens satisfy: 5.4 < R11 / f < 90; the effective focal length f of the optical lens and the image side curvature radius R12 of the sixth lens satisfy: 0.9 < R12 / f < 1.2.

[0012] Further preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -10.5 < f8 / f < -4.1; the effective focal length f of the optical lens and the object-side curvature radius R15 of the eighth lens satisfy: 2.7 < R15 / f < 90; the effective focal length f of the optical lens and the image-side curvature radius R16 of the eighth lens satisfy: 1.3 < R16 / f < 4.9.

[0013] 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: 1.1 < f123 / f < 2.8; 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: 2.7 < f45678 / f < 6.9.

[0014] Further preferably, 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: 0.15 < f123 / f45678 < 0.9; the combined focal length f67 of the sixth lens and the seventh 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: 0.7 < f67 / f45678 < 2.1.

[0015] Compared with the prior art, the optical lens provided by the present invention adopts eight lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be enhanced, enabling the lens to have one or more advantages such as a large viewing angle, a large aperture, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0019] Figure 4Graph showing the vertical axis chromatic aberration of the optical lens in Example 1 of the present invention.

[0020] Figure 5 This is the MTF curve of the optical lens in Example 1 of the present invention.

[0021] Figure 6 This is a relative illumination curve diagram of the optical lens in Example 1 of the present invention.

[0022] Figure 7 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0023] Figure 8 Graph showing the F-Tan (Theta) distortion of the optical lens in Example 2 of the present invention.

[0024] Figure 9 2 is an axial aberration curve diagram of the optical lens in Example 2 of the present invention.

[0025] Figure 10 Graph showing vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0026] Figure 11 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0027] Figure 12 This is a relative illumination curve diagram of the optical lens in Example 2 of the present invention.

[0028] Figure 13 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0029] Figure 14 Graph showing the F-Tan (Theta) distortion of the optical lens in Example 3 of the present invention.

[0030] Figure 15 Graph showing the axial aberration of the optical lens in Example 3 of the present invention.

[0031] Figure 16 Graph showing vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0032] Figure 17 This is the MTF curve of the optical lens in Example 3 of the present invention.

[0033] Figure 18 This is a relative illumination curve diagram of the optical lens in Example 3 of the present invention.

[0034] Figure 19 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

[0035] Figure 20Graph showing the F-Tan (Theta) distortion of the optical lens in Example 4 of the present invention.

[0036] Figure 21 4 is an axial aberration curve diagram of the optical lens in Example 4 of the present invention.

[0037] Figure 22 Graph showing vertical axis chromatic aberration of the optical lens in Example 4 of the present invention.

[0038] Figure 23 This is the MTF curve of the optical lens in Example 4 of the present invention.

[0039] Figure 24 This is a relative illumination curve diagram of the optical lens in Example 4 of the present invention.

[0040] Figure 25 Schematic diagram of the structure of the optical lens in Example 5 of the present invention.

[0041] Figure 26 FIG. 5 is a graph showing the F-Tan (Theta) distortion curve of the optical lens in Example 5 of the present invention.

[0042] Figure 27 4 is an axial aberration curve diagram of the optical lens in Example 5 of the present invention.

[0043] Figure 28 Graph showing vertical axis chromatic aberration of the optical lens in Example 5 of the present invention.

[0044] Figure 29 This is the MTF curve of the optical lens in Example 5 of the present invention.

[0045] Figure 30 This is a relative illumination curve diagram of the optical lens in Example 5 of the present invention.

[0046] Figure 31 Schematic diagram of the structure of the optical lens in Example 6 of the present invention.

[0047] Figure 32 FIG. 4 is a graph showing the F-Tan (Theta) distortion curve of the optical lens in Example 6 of the present invention.

[0048] Figure 33 Graph showing the axial aberration of the optical lens in Example 6 of the present invention.

[0049] Figure 34 Graph showing vertical axis chromatic aberration of the optical lens in Example 6 of the present invention.

[0050] Figure 35 This is the MTF curve of the optical lens in Example 6 of the present invention.

[0051] Figure 36This is a relative illumination curve diagram of the optical lens in Example 6 of the present invention.

[0052] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0053] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of embodiments of the present application and are not intended to limit the scope of the present 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.

[0054] It should be noted that in this specification, the terms "first," "second," "third," etc., are used solely to distinguish one feature from another and do not limit the features. Thus, the first lens discussed below could also be referred to as the second lens or the third lens without departing from the teachings of the present invention.

[0055] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0056] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, 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.

[0057] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application." And, the term "exemplary" is intended to refer to an example or illustration.

[0058] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0059] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0060] The optical lens provided in an embodiment of the present invention is composed of eight lenses, which are, along the optical axis from the object side to the imaging surface, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens.

[0061] In some embodiments, the first lens may have negative optical power, with its object-side surface being convex and its image-side surface being concave. The second lens may have negative optical power, with its object-side surface being concave and its image-side surface being concave. The third lens may have positive optical power, with its object-side surface being convex and its image-side surface being convex. The fourth lens may have negative optical power, with its object-side surface being convex and its image-side surface being concave. The fifth lens may have positive optical power, with its object-side surface being concave or convex, and its image-side surface being concave or convex. The sixth lens may have negative optical power, with its object-side surface being convex and its image-side surface being concave. The seventh lens may have positive optical power, with its object-side surface being convex and its image-side surface being convex. The eighth lens may have negative optical power, with its object-side surface being convex at the near optical axis and its image-side surface being concave at the near optical axis.

[0062] In some embodiments, the optical lens may further include an aperture, which may be located between the third lens and the fourth lens. It is understood that the aperture may be used to limit the amount of light entering to change the brightness of the image.

[0063] 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 to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0064] In some embodiments, the sixth lens and the seventh lens can be glued together to form a cemented 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. In some embodiments, the combined focal length f67 of the sixth lens and the seventh 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: 0.7 < f67 / f45678 < 2.1; the combined focal length f67 of the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 2.4 < f67 / f < 9.5. Satisfying the above ranges can further correct the chromatic aberration of the optical lens and reduce the eccentricity sensitivity of the optical lens. More specifically, 0.79 < f67 / f45678 < 1.9; 2.61 < f67 / f < 8.71.

[0065] In some embodiments, the radius of curvature R5 of the object side of the third lens and the radius of curvature R6 of the image side of the third lens satisfy: 0 < (R5 + R6) / (R5 - R6) < 0.4, and the radius of curvature R11 of the object side of the sixth lens and the radius of curvature R12 of the image side of the sixth lens satisfy: 0.6 < (R11 - R12) / (R11 + R12) < 1. Satisfying the above ranges can correct the aberration of the optical lens, ensure the smooth light path passing through the third and sixth lenses, reduce the tolerance sensitivity of the optical lens, and facilitate the smooth entry of light into the rear lens. More specifically, 0.03 < (R5 + R6) / (R5 - R6) < 0.34, 0.69 < (R11 - R12) / (R11 + R12) < 0.99.

[0066] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6 < TTL / f < 9; 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: 2.3 < TTL / IH < 3.6. Satisfying the above ranges, by reasonably controlling the overall length, focal length and image height of the optical lens, it helps the optical lens to achieve the balance of the overall length and volume, and is conducive to improving the structural stability of the optical lens. More specifically, 6.67 < TTL / f < 8.23, 2.54 < TTL / IH < 3.29.

[0067] In some embodiments, the maximum field of view angle FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 65° < FOV / FNO < 90°; the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4.1 < IH / EPD < 5.8. Meeting the above ranges helps to achieve the characteristics of a large field of view angle and a large aperture of the optical lens, is beneficial to increasing the light passing amount, and improving the relative illuminance. More specifically, 69.72° < FOV / FNO < 83.34°, 4.51 < IH / EPD < 5.29.

[0068] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.3 < IH / f < 2.9; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.7 < BFL / f < 1.1. 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, 2.5 < IH / f < 2.65, 0.75 < BFL / f < 0.98.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2 < f1 / f < -1.4, the effective focal length f of the optical lens and the object-side curvature radius R1 of the first lens satisfy: 2.7 < R1 / f < 6, 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 < 1.3; the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: 0.4 < (R1 - R2) / (R1 + R2) < 0.7. Meeting the above ranges enables the first lens to have an appropriate negative optical power and a reasonable surface type combination, helps to collect as much light with a large field of view angle as possible into the optical lens, obtain more picture information, and can control the trend of the large-angle light at the edge, improving the imaging quality of the optical lens. More specifically, -1.88 < f1 / f < -1.56, 2.96 < R1 / f < 5.52, 0.98 < R2 / f < 1.14; 0.49 < (R1 - R2) / (R1 + R2) < 0.67.

[0070] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.1 < f3 / f < 1.4. The effective focal length f of the optical lens and the object-side curvature radius R5 of the third lens satisfy: 1.4 < R5 / f < 2.6. The effective focal length f of the optical lens and the image-side curvature radius R6 of the third lens satisfy: -1.5 < R6 / f < -1.1. Meeting the above ranges makes the third lens have an appropriate positive optical power and surface shape, which helps to converge light, and the lens shape is gentle, which is beneficial to reducing the volume and cost. More specifically, 1.2 < f3 / f < 1.32, 1.49 < R5 / f < 2.4, -1.39 < R6 / f < -1.19.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.7 < f6 / f < -1.2. The effective focal length f of the optical lens and the object-side curvature radius R11 of the sixth lens satisfy: 5.4 < R11 / f < 90. The effective focal length f of the optical lens and the image-side curvature radius R12 of the sixth lens satisfy: 0.9 < R12 / f < 1.2. Meeting the above ranges can effectively improve the aberration of the edge field of view and enhance the overall imaging quality of the optical lens by reasonably setting the focal length and surface shape of the sixth lens. More specifically, -1.6 < f6 / f < -1.2 ; 5.98 < R11 / f < 82.92 ; 0.97 < R12 / 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: -10.5 < f8 / f < -4.1. The effective focal length f of the optical lens and the object-side curvature radius R15 of the eighth lens satisfy: 2.7 < R15 / f < 90. The effective focal length f of the optical lens and the image-side curvature radius R16 of the eighth lens satisfy: 1.3 < R16 / f < 4.9. Meeting the above ranges helps to control the light 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 by reasonably controlling the focal length ratio and surface shape of the eighth lens. More specifically, -9.85 < f8 / f < -4.54 ; 3.02 < R15 / f < 82.33 ; 1.43 < R16 / f < 4.48.

[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: 1.1 < f123 / f < 2.8; 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: 2.7 < f45678 / f < 6.9; 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: 0.15 < f123 / f45678 < 0.9. Meeting the above ranges is conducive to balancing the distortion and astigmatism generated by the front and rear end lenses of the optical lens and improving the imaging quality of the optical lens by reasonably setting the positive refractive power of the lens groups before and after the aperture. More specifically, 1.2 < f123 / f < 2.61; 3.05 < f45678 / f < 6.25; 0.18 < f123 / f45678 < 0.83.

[0074] In some embodiments, the effective focal length f of the optical lens, the maximum field angle FOV of the optical lens, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 50° < f × FOV / IH < 65°. Meeting the above range is conducive to achieving the balance between the large field angle and large target surface imaging of the optical lens by reasonably restricting the relationship between the focal length, field angle, and image height of the optical lens. More specifically, 53.3° < f × FOV / IH < 60.73°.

[0075] In some embodiments, the clear aperture semi-diameter 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: 0.2 < d1 / (IH / 2) / tan(FOV / 2) < 0.6. Meeting the above range can have a small front port diameter while meeting the requirements of the optical lens having a large field angle and a large image surface. More specifically, 0.25 < d1 / (IH / 2) / tan(FOV / 2) < 0.58.

[0076] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.8 < f2 / f < -1.5, the effective focal length f of the optical lens and the curvature radius R3 of the object side of the second lens satisfy: -5.7 < R3 / f < -2.8, and the effective focal length f of the optical lens and the curvature radius R4 of the image side of the second lens satisfy: 2.3 < R4 / f < 26. Meeting the above ranges enables the second lens to have an appropriate negative optical power and a reasonable surface type combination, which helps the divergent light enter the subsequent lenses smoothly and keeps the light trend stable. More specifically, -3.48 < f2 / f < -1.69, -5.2 < R3 / f < -3.04, 2.48 < R4 / f < 24.72.

[0077] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -3 < f4 / f < -1.8, and the effective focal length f of the optical lens and the object-side curvature radius R7 of the fourth lens satisfy: 2.5 < R7 / f < 5.2; the effective focal length f of the optical lens and the image-side curvature radius R8 of the fourth lens satisfy: 0.9 < R8 / f < 1.4. Meeting the above ranges helps to collect the light emitted from the front lens by reasonably controlling the focal length ratio and surface shape of the fourth lens, enables the collected light to smoothly enter the subsequent lenses, and is conducive to improving the resolution ability of the optical lens. More specifically, -2.84 < f4 / f < -2; 2.73 < R7 / f < 4.78; 0.99 < R8 / f < 1.23.

[0078] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.8 < f5 / f < 2.7. Meeting the above range helps to smooth the light trend of the front lens, correct the aberration generated by the front lens, and improve the imaging quality by reasonably controlling the focal length ratio of the fifth lens. More specifically, 1.82 < f5 / f < 2.51.

[0079] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1 < f7 / f < 1.4; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: 0.9 < R13 / f < 1.2; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: -12.7 < R14 / f < -2.1. Meeting the above ranges can better correct the chromatic aberration of the system in cooperation with the sixth lens and improve the overall imaging quality by reasonably setting the focal length and surface shape of the seventh lens. More specifically, 1.08 < f7 / f < 1.31; 0.97 < R13 / f < 1.13; -11.63 < R14 / f < -2.37.

[0080] In some embodiments, the optical lens satisfies the conditional formula: 2.2 mm < f < 2.7 mm, 1.1 mm < EPD < 1.5 mm, 16 mm < TTL < 21 mm, 1.6 < FNO < 2.2, 12° < CRA < 17°, 1.7 mm < BFL < 2.5 mm, 130° < FOV < 170°, 6 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 angle of the optical lens, and IH represents the true image height corresponding to the maximum field angle of the optical lens. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least the characteristics of a large field angle, a large aperture, and high imaging quality. More specifically, 2.42 mm < f < 2.47 mm, 1.2 mm < EPD < 1.36 mm, 16.43 mm < TTL < 20.1 mm, 1.7 < FNO < 2.1, 12.96° < CRA < 15.96°, 1.84 mm < BFL < 2.37 mm, 139.45° < FOV < 160.1°, 6.09 mm < IH < 6.47 mm.

[0081] 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. Additionally, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected due to the low dispersion characteristic of the glass itself. The first lens, second lens, fifth lens, sixth lens, and seventh lens in the optical lens provided by the present invention adopt glass lenses, and the third lens, fourth lens, and eighth lens adopt plastic lenses.

[0082] In some embodiments, the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving the miniaturization of the lens. More specifically, the third lens, fourth lens, fifth lens, and eighth lens of the present invention adopt aspherical lenses, and the first lens, second lens, sixth lens, and seventh lens adopt spherical lenses.

[0083] In each embodiment of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equation: ; Where z is the distance between the surface and the vertex in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the surface vertex, K is the quadratic surface coefficient, and B, C, D, E, F, G, and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients, respectively.

[0084] The present invention is further illustrated below with reference to several embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens vary; for details, please refer to the parameter tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the present invention is not limited thereto. Any other changes, substitutions, combinations, or simplifications that do not deviate from the novelties of the present invention shall be considered equivalent replacements and are included within the scope of protection of the present invention.

[0085] Example 1 See also Figure 1 , shown is a schematic structural diagram of the optical lens 100 provided in Example 1 of the present invention, which includes, along the optical axis from the object side to the imaging surface, 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.

[0086] The first lens L1 has negative refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave; The second lens L2 has negative refractive power, its object-side surface S3 is concave, and its image-side surface S4 is concave; The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is convex; The fourth lens L4 has negative refractive power, its object-side surface S7 is convex, and its image-side surface S8 is concave; The fifth lens L5 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is concave; The sixth lens L6 has negative refractive power, its object-side surface S11 is convex, and its image-side surface is concave; The seventh lens L7 has positive refractive power, its object-side surface is convex, and its image-side surface S13 is convex; The sixth lens L6 and the seventh lens L7 form a cemented lens group with positive refractive power. That is, the cemented surface between the image-side surface of the sixth lens L6 and the object-side surface of the seventh lens L7 is S13. The eighth lens L8 has negative refractive power, an object-side surface S14 thereof is convex at the near optical axis, and an image-side surface S15 thereof is concave at the near optical axis.

[0087] The object-side surface S16 and the image-side surface S17 of the filter G1 are both flat surfaces; The imaging surface S18 is a plane.

[0088] 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.

[0089] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0090] Table 1-1 The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0091] Table 1-2 Figure 2 The following figure shows the F-Tan (Theta) distortion curve of the optical lens 100 in this embodiment, which represents the distortion at different field angles on the imaging plane. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the distortion value changes relatively steadily with increasing field angle, indicating that the optical lens 100 is capable of effectively correcting distortion.

[0092] Figure 3 The following graph shows the axial aberration 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 graph, the offset of the axial aberration is controlled within a range of -0.05mm to 0.02mm, indicating that the optical lens 100 is able to effectively correct the axial aberration.

[0093] Figure 4 A graph showing the vertical chromatic aberration of the optical lens 100 in this embodiment shows the chromatic aberration of each wavelength relative to the central wavelength (0.555 μm) at different image heights on the imaging plane. The horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view angle. As can be seen from the graph, the vertical chromatic aberration for the longest and shortest wavelengths is controlled within a range of -1 μm to 4 μm, indicating that the optical lens 100 is capable of effectively correcting chromatic aberration.

[0094] Figure 5A modulation transfer function (MTF) graph of the optical lens 100 in this embodiment is shown. It represents the degree of lens imaging modulation at different spatial frequencies across various fields of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF value of this embodiment is consistently above 0.38 across the entire field of view, with a smooth and uniform decrease from the center to the edges of the field of view. This demonstrates excellent imaging quality and detail resolution at both low and high frequencies.

[0095] Figure 6 The relative illumination curve of the optical lens 100 in this embodiment is shown. It represents the relative illumination values ​​at different field angles on the imaging plane. The horizontal axis represents the half field angle (unit: degrees), and the vertical axis represents the relative illumination (unit: %). As can be seen from the graph, the relative illumination value of the optical lens is still greater than 80% at the maximum half field angle, indicating that the optical lens has good relative illumination.

[0096] Example 2 See also Figure 7 , shown is a schematic structural diagram of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, this embodiment has the following main differences: the object-side surface S9 of the fifth lens L5 is concave; the image-side surface S10 of the fifth lens L5 is convex; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0097] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0098] Table 2-1 The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0099] Table 2-2 In this embodiment, the F-Tan (Theta) distortion curve, the axial aberration curve, the vertical chromatic aberration curve, the MTF curve, and the relative illumination diagram of the optical lens 200 are shown as follows: Figures 8 to 12 shown.

[0100] from Figure 8 It can be seen from the figure that as the field of view angle increases, the distortion value changes more steadily, indicating that the optical lens 200 can correct the distortion well.

[0101] from Figure 9 It can be seen from the figure that the offset of the axial aberration is controlled within -0.2mm~0.05mm, which shows that the optical lens 200 can correct the axial aberration well.

[0102] from Figure 10 It can be seen from the figure that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -1μm~3μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0103] from Figure 11 As can be seen, the MTF value of this embodiment is above 0.38 throughout the entire field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, achieving good imaging quality and detail resolution in both low-frequency and high-frequency conditions.

[0104] from Figure 12 It can be seen from the figure that the relative illumination value of the optical lens is still greater than 70% at the maximum half field of view angle, indicating that the optical lens 200 has good relative illumination.

[0105] Example 3 See also Figure 13 , shown is a schematic structural diagram of an optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image-side surface S10 of the fifth lens L5 is a convex surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0106] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0107] Table 3-1 The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0108] Table 3-2 In this embodiment, the F-Tan (Theta) distortion curve, the axial aberration curve, the vertical chromatic aberration curve, the MTF curve, and the relative illumination diagram of the optical lens 300 are shown as follows: Figures 14 to 18 shown.

[0109] from Figure 14 It can be seen from the figure that as the field of view angle increases, the distortion value changes more steadily, indicating that the optical lens 300 can correct the distortion well.

[0110] from Figure 15 It can be seen from the figure that the offset of the axial aberration is controlled within -0.02 mm to 0.02 mm, indicating that the optical lens 300 can correct the axial aberration well.

[0111] from Figure 16It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within 0~3μm, indicating that the optical lens 300 can correct the chromatic aberration well.

[0112] from Figure 17 As can be seen from the figure, the MTF value of this embodiment is above 0.4 throughout the entire field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, achieving good imaging quality and detail resolution in both low-frequency and high-frequency conditions.

[0113] from Figure 18 It can be seen that the relative illumination value of the optical lens is still greater than 70% at the maximum half field of view angle, indicating that the optical lens has good relative illumination.

[0114] Example 4 See also Figure 19 , shown is a schematic structural diagram of an optical lens 400 provided in Example 4 of the present invention. Compared with Example 1, this embodiment mainly differs in that: the image-side surface S10 of the fifth lens L5 is a convex surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0115] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0116] Table 4-1 The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0117] Table 4-2 In this embodiment, the F-Tan (Theta) distortion curve, the axial aberration curve, the vertical chromatic aberration curve, the MTF curve, and the relative illumination diagram of the optical lens 400 are shown as follows: Figures 20 to 24 shown.

[0118] from Figure 20 It can be seen from the figure that as the field of view angle increases, the distortion value changes more steadily, indicating that the optical lens 400 can correct the distortion well.

[0119] from Figure 21 It can be seen that the offset of the axial aberration is controlled within -0.02mm~0.02mm, indicating that the optical lens 400 can correct the axial aberration well.

[0120] from Figure 22 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within 0~3μm, indicating that the optical lens 400 can correct chromatic aberration well.

[0121] from Figure 23 As can be seen, the MTF value of this embodiment is above 0.45 throughout the entire field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, achieving good imaging quality and detail resolution in both low-frequency and high-frequency conditions.

[0122] from Figure 24 It can be seen that the relative illumination value of the optical lens is still greater than 70% at the maximum half field of view angle, indicating that the optical lens has good relative illumination.

[0123] Example 5 See also Figure 25 , shown is a schematic structural diagram of an optical lens 500 provided in Example 5 of the present invention. Compared with Example 1, this embodiment mainly differs in that: the image-side surface S10 of the fifth lens L5 is a convex surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0124] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0125] Table 5-1 The surface parameters of the aspheric lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0126] Table 5-2 In this embodiment, the F-Tan (Theta) distortion curve, the axial aberration curve, the vertical chromatic aberration curve, the MTF curve, and the relative illumination diagram of the optical lens 500 are shown as follows: Figures 26 to 30 shown.

[0127] from Figure 26 It can be seen from the figure that as the field of view angle increases, the distortion value changes more steadily, indicating that the optical lens 500 can correct the distortion well.

[0128] from Figure 27 It can be seen that the offset of the axial aberration is controlled within -0.02mm~0.02mm, indicating that the optical lens 500 can correct the axial aberration well.

[0129] from Figure 28 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within 0~3μm, indicating that the optical lens 500 can correct chromatic aberration well.

[0130] from Figure 29As can be seen from the figure, the MTF value of this embodiment is above 0.5 throughout the entire field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, achieving good imaging quality and detail resolution in both low-frequency and high-frequency conditions.

[0131] from Figure 30 It can be seen that 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.

[0132] Example 6 See also Figure 31 , shown is a schematic structural diagram of an optical lens 600 provided in Example 6 of the present invention. Compared with Example 1, this embodiment mainly differs in that: the image-side surface S10 of the fifth lens L5 is a convex surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0133] The relevant parameters of each lens in the optical lens 600 in Example 6 are shown in Table 6-1.

[0134] Table 6-1 The surface parameters of the aspheric lens of the optical lens 600 in Example 6 are shown in Table 6-2.

[0135] Table 6-2 In this embodiment, the F-Tan (Theta) distortion curve, the axial aberration curve, the vertical chromatic aberration curve, the MTF curve, and the relative illumination diagram of the optical lens 600 are shown as follows: Figures 32 to 36 shown.

[0136] from Figure 32 It can be seen from the figure that as the field of view angle increases, the distortion value changes more steadily, indicating that the optical lens 600 can correct the distortion well.

[0137] from Figure 33 It can be seen that the offset of the axial aberration is controlled within -0.02mm~0.02mm, indicating that the optical lens 600 can correct the axial aberration well.

[0138] from Figure 34 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within 0~3μm, indicating that the optical lens 600 can correct chromatic aberration well.

[0139] from Figure 35As can be seen from the figure, the MTF value of this embodiment is above 0.4 throughout the entire field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, achieving good imaging quality and detail resolution in both low-frequency and high-frequency conditions.

[0140] from Figure 36 It can be seen that the relative illumination value of the optical lens is still greater than 70% at the maximum half field of view angle, indicating that the optical lens has good relative illumination.

[0141] Please refer to Table 7-1 and Table 7-2, which show the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value FNO, the real image height IH corresponding to the maximum field of view angle, the main ray incident angle CRA at the maximum image height, the maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0142] Table 7-1 Table 7-2 In summary, the optical lens provided by the present invention uses eight lenses with specific optical powers. Through the combination of specific surface shapes and reasonable optical power distribution, it is possible to improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, so that the lens has one or more advantages such as a large field of view, a large aperture, and high imaging quality.

[0143] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations 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 any one or more embodiments or examples.

[0144] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An optical lens, consisting of eight lenses, characterized in that: It successively includes from the object side to the imaging surface along the optical axis: A first lens with a negative optical power, whose object side is 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 concave; A third lens with a positive optical power, whose object side is convex and whose image side is convex; A fourth lens with a negative optical power, whose object side is convex and whose image side is concave; A fifth lens with a positive optical power; A sixth lens with a negative optical power, whose object side is convex and whose image side is concave; A seventh lens with a positive optical power, whose object side is convex and whose image side is convex; 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 R5 of the object side of the third lens and the curvature radius R6 of the image side of the third lens satisfy: 0 < (R5 + R6) / (R5 - R6) < 0.4, and the curvature radius R11 of the object side of the sixth lens and the curvature radius R12 of the image side of the sixth lens satisfy: 0.6 < (R11 - R12) / (R11 + R12) < 1.

2. The optical lens according to claim 1, wherein: The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6 < TTL / f < 9; 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: 2.3 < TTL / IH < 3.

6.

3. The optical lens according to claim 1, wherein: The maximum field angle FOV of the optical lens and the f-number FNO of the optical lens satisfy: 65° < FOV / FNO < 90°; 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: 4.1 < IH / EPD < 5.

8.

4. The optical lens according to claim 1, wherein: 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: 2.3 < IH / f < 2.9; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.7 < BFL / f < 1.

1.

5. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2 < f1 / f < -1.4, the effective focal length f of the optical lens and the curvature radius R1 of the object side of the first lens satisfy: 2.7 < R1 / f < 6, 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 < 1.3, and the curvature radius R1 of the object side of the first lens and the curvature radius R2 of the image side of the first lens satisfy: 0.4 < (R1 - R2) / (R1 + R2) < 0.

7.

6. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.1 < f3 / f < 1.4, the effective focal length f of the optical lens and the curvature radius R5 of the object side of the third lens satisfy: 1.4 < R5 / f < 2.6, and the effective focal length f of the optical lens and the curvature radius R6 of the image side of the third lens satisfy: -1.5 < R6 / f < -1.

1.

7. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.7 < f6 / f < -1.2, and the effective focal length f of the optical lens and the object-side curvature radius R11 of the sixth lens satisfy: 5.4 < R11 / f < 90; the effective focal length f of the optical lens and the image-side curvature radius R12 of the sixth lens satisfy: 0.9 < R12 / f < 1.

2.

8. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -10.5 < f8 / f < -4.1; the effective focal length f of the optical lens and the object-side curvature radius R15 of the eighth lens satisfy: 2.7 < R15 / f < 90; the effective focal length f of the optical lens and the image-side curvature radius R16 of the eighth lens satisfy: 1.3 < R16 / f < 4.

9.

9. The optical lens according to claim 1, wherein: 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: 1.1 < f123 / f < 2.8; 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: 2.7 < f45678 / f < 6.

9.

10. The optical lens according to claim 1, wherein: 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: 0.15 < f123 / f45678 < 0.9; the combined focal length f67 of the sixth lens and the seventh 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: 0.7 < f67 / f45678 < 2.1.

Images