Optical lens

Abstract

The invention provides an optical lens, which comprises eight lenses from an object side to an imaging surface along an optical axis: 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, 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 third lens has positive focal power; the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface; the object side surface of the sixth lens is a concave surface, and the image side surface of the sixth lens is a concave surface; the seventh lens has positive focal power, and the object side surface of the seventh lens is a convex surface; the object side surface of the eighth lens is a concave surface, and the image side surface of the eighth lens is a convex surface. According to the optical lens provided by the invention, through specific surface shape matching and reasonable focal power distribution, the lens has one or more advantages of an ultra-wide angle, a large image plane, a 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] As people's requirements for driving experience continue to increase, automotive optical lenses are increasingly used in intelligent driving, and the status of automotive optical lenses in the automotive-related industries continues to improve.

[0003] Advanced Driver Assistance Systems (ADAS) play a crucial role in intelligent driving. They use various lenses and sensors to collect environmental information to ensure driver safety. Existing ADAS systems require not only a thin, compact form factor with high pixel count and resolution, but also the ability to produce clear images in low-light conditions. Therefore, developing an optical lens with excellent imaging performance is crucial. 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:

[0006] An optical lens, comprising eight lenses, including the following elements along the optical axis from the object side to the imaging surface:

[0007] The first lens has a negative optical power, its object-side surface is convex and its image-side surface is concave;

[0008] a second lens having negative optical power, wherein the object-side surface and the image-side surface are concave;

[0009] a third lens having positive optical power;

[0010] a fourth lens element having positive refractive power, whose object-side surface is convex and whose image-side surface is convex;

[0011] a fifth lens element having positive refractive power, whose object-side surface and image-side surface are convex;

[0012] a sixth lens element having negative optical power, whose object-side surface and image-side surface are concave;

[0013] a seventh lens element having positive optical power and a convex object-side surface;

[0014] an eighth lens element having positive refractive power, whose object-side surface is concave and whose image-side surface is convex;

[0015] Among them, the curvature radius R7 of the object side surface of the fourth lens and the curvature radius R8 of the image side surface of the fourth lens satisfy: -0.7 < (R7 + R8) / (R7 - R8) < -0.3; the curvature radius R15 of the object side surface of the eighth lens and the curvature radius R16 of the image side surface of the eighth lens satisfy: 0.4 < (R15 - R16) / (R15 + R16) < 0.7.

[0016] Further preferably, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 7 < TTL / f < 8.5; the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 3 < TTL / IH < 3.5.

[0017] Further preferably, the maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 80° < FOV / Fno < 100°; the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.6 < IH / EPD < 4.5.

[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: 2.2 < IH / f < 2.6; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.89 < BFL / f < 0.92.

[0019] Further preferably, the clear aperture d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 0.44 < d1 / (IH / 2) / tan(FOV / 2) < 0.57; 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: -1.2 < f123 / f45678 < -0.6.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.8 < f1 / f < -1.9; the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 3.2 < f3 / f < 10.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.1 < f2 / f < -1.9; 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) < 0.2.

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.8 < f4 / f < 2.85; the radius of curvature R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3 < R7 / f < 2.3; the radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -7.5 < R8 / f < -3.6.

[0023] Further preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.3 < f5 / f < 2.2; the radius of curvature R9 of the object side surface of the fifth lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: -0.2 < (R9 + R10) / (R9 - R10) < 0.2.

[0024] Further preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 13 < f8 / f < 19; 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: -55 < R15 / f < -26; 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: -11 < R16 / f < -8.

[0025] The optical lens provided by the present invention adopts 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, enabling the lens to have one or more advantages such as ultra-wide angle, large image plane, 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 the F-Tan(Theta) distortion curve of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 3 is the MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 4 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0031] Figure 5: This is the F-Tan (Theta) distortion curve of the optical lens in Example 2 of the present invention.

[0032] Figure 6 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0033] Figure 7 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0034] Figure 8 : This is the F-Tan (Theta) distortion curve of the optical lens in Example 3 of the present invention.

[0035] Figure 9 This is the MTF curve of the optical lens in Example 3 of the present invention.

[0036] Figure 10 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

[0037] Figure 11 : This is the F-Tan (Theta) distortion curve of the optical lens in Example 4 of the present invention.

[0038] Figure 12 This is the MTF curve of the optical lens in Example 4 of the present invention.

[0039] Figure 13 Schematic diagram of the structure of the optical lens in Example 5 of the present invention.

[0040] Figure 14 : This is the F-Tan (Theta) distortion curve of the optical lens in Example 5 of the present invention.

[0041] Figure 15 This is the MTF curve of the optical lens in Example 5 of the present invention.

[0042] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] The optical lens provided by the embodiment of the present invention comprises eight lenses, which are arranged in order from the object side to the imaging surface along the optical axis: 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.

[0051] 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 concave or convex, and its image-side surface being concave or convex. The fourth lens may have positive optical power, with its object-side surface being convex and its image-side surface being convex. The fifth lens may have positive optical power, with its object-side surface being convex and its image-side surface being convex. The sixth lens may have negative optical power, with its object-side surface being concave 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 concave or convex. The eighth lens may have positive optical power, with its object-side surface being concave and its image-side surface being convex.

[0052] In some embodiments, the optical lens may further include an aperture, which may be located between the third and fourth lens elements. It is understood that the aperture is used to limit the amount of light entering, thereby changing the brightness of the image. When the aperture is located between the third and fourth lens elements, it facilitates correction of aperture aberrations.

[0053] In some embodiments, the optical lens may further include a filter and a protective glass. The filter and protective glass may be positioned sequentially along the optical axis between the eighth lens and the imaging plane. The filter is used to filter out interfering light, preventing it from reaching the imaging plane of the optical lens and affecting normal imaging. The protective glass protects the optical lens, preventing damage to the photosensitive chip that could affect the lens's imaging performance.

[0054] In some embodiments, the fifth lens, the sixth lens, and the seventh lens may be cemented together to form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the decentration 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 difficulty of the processing technology of the optical lens and improving the assembly yield of the optical lens.

[0055] In some embodiments, the object-side curvature radius R7 of the fourth lens element and the image-side curvature radius R8 of the fourth lens element satisfy the following range: -0.7 < (R7 + R8) / (R7 - R8) < -0.3. Meeting this range facilitates focusing light while correcting field curvature and distortion of the optical lens, thereby improving the imaging quality of the optical lens. More specifically, -0.65 < (R7 + R8) / (R7 - R8) < -0.36.

[0056] In some embodiments, the radius of curvature R15 of the object side surface of the eighth lens and the radius of curvature R16 of the image side surface of the eighth lens satisfy: 0.4 < (R15 - R16) / (R15 + R16) < 0.7. Meeting the above range is beneficial to suppressing the angle of the marginal field of view incident on the imaging surface, effectively transmitting more light beams to the imaging surface, and at the same time being able to balance the field curvature and spherical aberration of the optical lens, improving the imaging quality of the optical lens. More specifically, 0.47 < (R15 - R16) / (R15 + R16) < 0.69.

[0057] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 7 < TTL / f < 8.5. Meeting the above range can effectively limit the length of the lens, which is beneficial to the miniaturization of the optical lens. More specifically, 7.77 < TTL / f < 8.07.

[0058] In some embodiments, the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3 < TTL / IH < 3.5. Meeting the above range ensures that, under the condition of the same overall length of the lens, it has a larger image surface, can match a larger-sized imaging chip to achieve high-definition imaging, and better realizes the balance of the small overall length and the large image surface of the lens. More specifically, 3.19 < TTL / IH < 3.33. <​​​​​​​​​In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.89 < BFL / f < 0.92. Meeting the above range limits the optical lens to have an appropriate back focus, facilitating the reasonable arrangement of the positions of each lens and reducing the processing and assembly difficulty at the same time.

[0063] In some embodiments, the clear aperture d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.44 < d1 / (IH / 2) / tan(FOV / 2) < 0.57. Meeting the above range can have a small front aperture while meeting the requirements of the optical lens having a large field angle and a large image plane.

[0064] In some embodiments, 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: -1.2 < f123 / f45678 < -0.6. Meeting the above range, by reasonably setting the relationship between the lens groups before and after the aperture stop, it is beneficial to balance various aberrations generated by the lens groups and improve the overall imaging quality. More specifically, -1.12 < f123 / f45678 < -0.68.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.8 < f1 / f < -1.9. Meeting the above range, by setting the first lens to have a negative refractive power, it is beneficial for the first lens to receive light at a larger angle and collect as much light as possible into the rear optical system, increasing the light flux while achieving a large field of view. More specifically, -2.61 < f1 / f < -2.13.

[0066] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 3.2 < f3 / f < 10. Meeting the above range limits the third lens to have an appropriate positive optical power, which has the effect of converging light rays, depressing the height of peripheral light rays, and is beneficial for reducing the aperture of the rear lens. More specifically, 3.57 < f3 / f < 9.22.

[0067] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.1 < f2 / f < -1.9; 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) < 0.2; the radius of curvature R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: -3.1 < R3 / f < -1.9; the radius of curvature R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: 1.7 < R4 / f < 9.6. Meeting the above ranges enables the second lens to have a negative optical power and a double concave surface shape, which has the effect of diverging light rays. At the same field angle, the light rays exiting from the image side surface of the first lens are further diverged, and the central rays and marginal rays of each field can be dispersed, allowing the rear optical system to have a larger light receiving surface to receive the light rays exiting from the image side surface of the second lens, achieving a larger light input, and being beneficial to increasing the relative illumination. More specifically, -2.91 < f2 / f < -2.07; -0.63 < (R3 + R4) / (R3 - R4) < 0.18; -2.85 < R3 / f < -2.07; 1.86 < R4 / f < 8.87.

[0068] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.8 < f4 / f < 2.85; the radius of curvature R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3 < R7 / f < 2.3; the radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -7.5 < R8 / f < -3.6. Meeting the above ranges, the fourth lens has a positive optical power and a double convex surface shape, which can further focus the light rays, adjust the angle of the principal ray, optimize the imaging quality, and correct the remaining aberrations (such as distortion, chromatic aberration, etc.), reducing the distortion of the wide-angle lens. More specifically, 1.99 < f4 / f < 2.63; 1.49 < R7 / f < 2.09; -6.92 < R8 / f < -4.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.3 < f5 / f < 2.2; the curvature radius R9 of the object side surface of the fifth lens and the curvature radius R10 of the image side surface of the fifth lens satisfy: -0.2 < (R9 + R10) / (R9 - R10) < 0.2; the curvature radius R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 1.3 < R9 / f < 2.2; the curvature radius R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -2.4 < R10 / f < -1.4. Satisfying the above ranges is beneficial to the convergence of light rays, sharing the positive optical power of the third lens and the fourth lens, avoiding excessive light ray deflection, and better achieving high-quality imaging of the lens. More specifically, 1.39 < f5 / f < 1.98; -0.16 < (R9 + R10) / (R9 - R10) < 0.11; 1.48 < R9 / f < 1.97; -2.19 < R10 / f < -1.51.

[0070] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 13 < f8 / f < 19; the curvature radius R15 of the object side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -55 < R15 / f < -26; the curvature radius R16 of the image side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -11 < R16 / f < -8. Satisfying the above ranges, setting the eighth lens to have a positive refractive power and a suitable surface shape is beneficial to the convergence of light rays, making the light ray trend transition smoothly to the rear, reducing the height of the light rays incident on the rear, slowing down the upward trend of the light rays, avoiding the light energy loss caused by the excessive main light ray angle of the large field of view light rays when reaching the imaging surface, being beneficial to improving the illuminance of the edge field of view, and being beneficial to achieving a short optical total length. More specifically, 14.13 < f8 / f < 17.76; -53.05 < R15 / f < -29.07; -10.11 < R16 / f < -8.78.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1 < f6 / f < -0.7. Satisfying the above ranges makes the light rays in the edge field of view show an upward trend, which is beneficial to the image points on the imaging surface moving away from the optical axis, so as to be beneficial to achieving the effect of matching with a large chip, obtaining a larger picture, effectively eliminating aberration, and improving the resolution ability of the optical lens. More specifically, -0.96 < f6 / f < -0.73.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.2 < f7 / f < 2.3. Meeting the above range is beneficial for light convergence, enabling the light path to smoothly transition to the rear, reducing the height of the light incident on the rear, slowing down the upward trend of the light, avoiding light energy loss caused by an excessive chief ray angle of the large field of view light when reaching the imaging surface, facilitating the improvement of the illuminance of the edge field of view, and being conducive to achieving a short overall optical length. More specifically, 1.36 < f7 / f < 2.09.

[0073] In some embodiments, the optical lens satisfies the following conditional expressions: 5 mm < f < 6 mm; 3 mm < EPD < 3.8 mm; 40 mm < TTL < 50 mm; 1.5 < Fno < 1.8; 16° < CRA < 22°; 5 mm < BFL < 5.2 mm; 140° < FOV < 160°; 13 mm < IH < 14 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the overall optical length of the optical lens, Fno represents the aperture value of the optical lens, CRA represents the chief ray angle of incidence of the optical lens, 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 range, the optical lens has at least one or more advantages such as ultra-wide angle, large target surface, and large aperture. More specifically, 5.6 mm < f < 5.67 mm; 3.3 mm < EPD < 3.49 mm; 43.83 mm < TTL < 45.21 mm; 1.6 < Fno < 1.71; 16.68° < CRA < 21.46°; 5.07 mm < BFL < 5.09 mm; 143.9° < FOV < 150.3°; 13.6 mm < IH < 13.71 mm.

[0074] 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, due to the low dispersion characteristic of the glass itself, the geometric chromatic aberration of the optical system can be effectively corrected. The optical lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0075] In some embodiments, the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses may be spherical or aspherical lenses. Compared to spherical lenses, aspherical structures can effectively reduce aberrations in the optical system, thereby reducing the number and size of lenses and achieving better miniaturization. More specifically, the fourth and eighth lenses of the present invention are aspherical lenses, while the first, second, third, fifth, sixth, and seventh lenses are spherical lenses.

[0076] In various embodiments of the present invention, when the lens is an aspheric lens, the shapes of the aspheric surfaces of the optical lens satisfy the following equations:

[0077]

[0078] 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, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients, respectively.

[0079] 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.

[0080] Example 1

[0081] See also Figure 1 , shown is a schematic structural diagram of the optical lens 100 provided in Example 1 of the present invention. The optical lens 100 includes, in order from the object side to the imaging surface along the optical axis: 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, a filter G1, and a protective glass G2.

[0082] The first lens L1 has negative refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave;

[0083] The second lens L2 has negative refractive power, its object-side surface S3 is concave, and its image-side surface S4 is concave;

[0084] The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is convex;

[0085] The fourth lens L4 has positive refractive power, its object-side surface S7 is convex, and its image-side surface S8 is convex;

[0086] The fifth lens L5 has positive refractive power, its object-side surface S9 is convex, and its image-side surface is convex;

[0087] The sixth lens L6 has negative optical power, and its object-side surface and image-side surface are concave.

[0088] The seventh lens L7 has positive refractive power, its object-side surface is convex, and its image-side surface S12 is concave;

[0089] The fifth lens L5, 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 fifth lens L5 and the object-side surface of the sixth lens L7 is S10, and the cemented surface between the image-side surface of the sixth lens L6 and the object-side surface of the seventh lens L7 is S11.

[0090] The eighth lens L8 has positive refractive power, its object-side surface S13 is concave, and its image-side surface S14 is convex;

[0091] The object-side surface S15 and the image-side surface S16 of the filter G1 are both flat surfaces;

[0092] The object side surface S17 and the image side surface S18 of the protective glass G2 are both flat surfaces;

[0093] The imaging surface S19 is a plane.

[0094] The fourth lens L4 and the eighth lens L8 are glass aspherical lenses; the first lens L1, the second lens L2, the third lens L3, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are glass spherical lenses.

[0095] Table 1 shows the parameters of the lenses in the optical lens 100 in Example 1.

[0096] Table 1

[0097]

[0098] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0099] Table 1-2

[0100] Face number K B C D E F S7 -1.86E+00 2.50E-04 9.65E-07 5.75E-08 -4.10E-09 1.23E-10 S8 1.14E+01 1.98E-04 -1.00E-06 2.45E-07 -1.04E-08 2.24E-10 S13 -2.00E+02 -1.34E-03 -1.63E-05 -7.27E-07 -1.72E-08 3.66E-10 S14 -4.73E+01 -7.53E-04 -1.42E-06 4.09E-08 1.26E-09 -2.60E-12

[0101] Figure 2The F-Tan (Theta) distortion curve for Example 1 shows the distortion of light of different wavelengths at different image heights on the imaging surface. 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 of the optical lens 100 is controlled within a range of -60% to 0%, and the image compression in the edge angle area is relatively smooth, effectively improving the clarity of the expanded image.

[0102] Figure 3 The MTF (Modulation Transfer Function) curve for Example 1 is shown, representing the degree of lens imaging modulation at different spatial frequencies across the field of view. The horizontal axis represents spatial frequency (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. Within the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating excellent imaging quality and detail resolution at both low and high frequencies.

[0103] Example 2

[0104] See also Figure 4 , 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 mainly differs in that: the image-side surface S14 of the seventh lens L7 is a convex surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0105] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0106] Table 2-1

[0107]

[0108] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0109] Table 2-2

[0110] Face number K B C D E F S7 -1.31E+00 1.55E-04 4.09E-08 2.16E-07 -1.03E-08 2.40E-10 S8 -2.81E+00 4.42E-05 -2.53E-07 2.28E-07 -1.16E-08 2.87E-10 S13 2.00E+02 -9.30E-04 -8.52E-06 -5.35E-07 1.57E-08 -5.79E-10 S14 -2.00E+02 -8.32E-04 3.99E-06 -1.68E-07 4.07E-09 -5.15E-11

[0111] from Figure 5 It can be seen from the figure that the distortion of the optical lens 200 is controlled within a range of -65% to 0, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the expanded image.

[0112] from Figure 6 It can be seen that the MTF value of this embodiment is above 0.3 in the entire field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0113] Example 3

[0114] See also Figure 7 , shown is a schematic structural diagram of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main differences between this embodiment and Example 1 are: the image-side surface S6 of the third lens L3 is convex; 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 300 in Example 3 are shown in Table 3-1.

[0116] Table 3-1

[0117]

[0118] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0119] Table 3-2

[0120]

[0121]

[0122] from Figure 8 It can be seen from the figure that the distortion of the optical lens 300 is controlled within -60% to 0, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the expanded image.

[0123] from Figure 9 It can be seen that the MTF value of this embodiment is above 0.28 in the entire field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0124] Example 4

[0125] See also Figure 10 , 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 object-side surface S5 of the third lens L3 is a concave surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0126] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0127] Table 4-1

[0128]

[0129] The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0130] Table 4-2

[0131]

[0132]

[0133] from Figure 11 It can be seen from the figure that the distortion of the optical lens 400 is controlled within a range of -70% to 0, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the expanded image.

[0134] from Figure 12 It can be seen that the MTF value of this embodiment is above 0.3 in the entire field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0135] Example 5

[0136] See also Figure 13 , 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 object-side surface S5 of the third lens L3 is concave; the image-side surface S14 of the seventh lens L7 is convex; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0137] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0138] Table 5-1

[0139]

[0140] The surface parameters of the aspheric lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0141] Table 5-2

[0142] Face number K B C D E F S7 -5.62E-01 1.04E-04 3.02E-06 2.48E-08 7.79E-11 5.41E-11 S8 6.38E+00 2.37E-04 2.26E-06 2.57E-07 -1.15E-08 3.65E-10 S13 -2.00E+02 -9.05E-04 -1.13E-05 -2.62E-08 -1.22E-08 2.36E-10 S14 6.13E+01 -6.02E-04 -2.09E-06 7.10E-08 -9.44E-10 1.24E-11

[0143] from Figure 14 It can be seen from the figure that the distortion of the optical lens 500 is controlled within -70% to 0, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the expanded image.

[0144] from Figure 15 It can be seen that the MTF value of this embodiment is above 0.28 in the entire field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0145] Please refer to Table 6, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, real image height IH corresponding to the maximum field of view angle, maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0146] Table 6

[0147]

[0148]

[0149] 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 ultra-wide angle, large image surface, large aperture, and high imaging quality.

[0150] 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.

[0151] 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, 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 concave; A third lens with a positive optical power; A fourth lens with a positive optical power, whose object side is convex and whose image side is convex; A fifth lens with a positive optical power, whose object side is convex and whose image side is convex; A sixth lens with a negative optical power, whose object side is concave and whose image side is concave; A seventh lens with a positive optical power, whose object side is convex; An eighth lens with a positive optical power, whose object side is concave and whose image side is convex; Wherein, the curvature radius R7 of the object side of the fourth lens and the curvature radius R8 of the image side of the fourth lens satisfy: -0.7 < (R7 + R8) / (R7 - R8) < -0.3; the curvature radius R15 of the object side of the eighth lens and the curvature radius R16 of the image side of the eighth lens satisfy: 0.4 < (R15 - R16) / (R15 + R16) < 0.

7.

2. The optical lens according to claim 1, wherein: The overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 7 < TTL / f < 8.5; the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 3 < TTL / IH < 3.

5.

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: 80° < FOV / Fno < 100°; the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.6 < IH / EPD < 4.

5.

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: 2.2 < IH / f < 2.6; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.89 < BFL / f < 0.

92.

5. The optical lens according to claim 1, wherein: The clear 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: 0.44 < d1 / (IH / 2) / tan(FOV / 2) < 0.57; 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: -1.2 < f123 / f45678 < -0.

6.

6. 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: -2.8 < f1 / f < -1.9; the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 3.2 < f3 / f < 10.

7. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.1 < f2 / f < -1.9; 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.

2.

8. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.8 < f4 / f < 2.85; the curvature radius R7 of the object side of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3 < R7 / f < 2.3; the curvature radius R8 of the image side of the fourth lens and the effective focal length f of the optical lens satisfy: -7.5 < R8 / f < -3.

6.

9. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.3 < f5 / f < 2.2; the curvature radius R9 of the object side of the fifth lens and the curvature radius R10 of the image side of the fifth lens satisfy: -0.2 < (R9 + R10) / (R9 - R10) < 0.

2.

10. 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: 13 < f8 / f < 19; the curvature radius R15 of the object side of the eighth lens and the effective focal length f of the optical lens satisfy: -55 < R15 / f < -26; the curvature radius R16 of the image side of the eighth lens and the effective focal length f of the optical lens satisfy: -11 < R16 / f < -8.

Images