Optical lens

Abstract

The invention provides an optical lens, which comprises eight lenses with focal power and sequentially comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with positive focal power, a fifth lens with negative focal power and a sixth lens with negative focal power from an object side to an imaging surface along an optical axis, the object side surface of the second lens is a convex surface; the third lens has negative focal power, and the image side surface of the third lens is a concave surface; the object side surface of the fourth lens is a concave 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 object side surface of the seventh lens is a concave surface, and the image side surface of the seventh lens is a concave surface; and the eighth lens has negative focal power. The optical lens provided by the invention has one or more advantages of long focus, 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] With the booming development of assisted driving and autonomous driving technologies, in-vehicle cameras play a crucial role. There are various types of in-vehicle cameras, including interior, rear, front, side, and surround view cameras. Each has unique functions and serves different application scenarios. For example, a forward-looking wide-angle camera is primarily used to accurately identify close-range objects, providing critical information for driving in urban road conditions and low-speed driving scenarios.

[0003] Forward-facing cameras are a core component of ADAS (Advanced Driver Assistance Systems). They not only measure distance but also accurately identify objects and clearly discern road markings. This requires extremely complex visual algorithms and a high technical barrier to entry. To fully leverage the performance of forward-facing cameras, developing an optical lens with superior imaging quality is imperative. Only by doing so can they ensure stable and efficient operation in complex driving environments, laying a solid foundation for the further development of autonomous driving technology. 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, comprising eight lenses having optical power, including the following elements in order from the object side to the imaging plane along the optical axis: The first lens has a negative optical power, its object-side surface is concave, and its image-side surface is convex; a second lens having positive optical power and a convex object-side surface; a third lens element having negative optical power and a concave image-side surface; a fourth lens element having positive refractive power, whose object-side surface is concave and whose image-side surface is convex; a fifth lens element having positive refractive power, whose object-side surface and image-side surface are convex; a sixth lens element having negative optical power, whose object-side surface and image-side surface are concave; a seventh lens element having negative optical power, whose object-side surface and image-side surface are concave; an eighth lens having negative optical power; The combined focal length f12 of the first lens and the second lens and the combined focal length f345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy the following conditions: -0.85 <f12 / f345678<0。

[0006] More preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.5 < TTL / f < 1.8; 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: 2.6 < TTL / IH < 3.2.

[0007] More 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: 0.5 < IH / f < 0.6; the semi-aperture d1 of the light passing through 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: 3.8 < d1 / (IH / 2) / Tan(FOV / 2) < 4.5.

[0008] More preferably, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.9 < f1 / f < -1.2; the curvature radius R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -0.5 < R1 / f < -0.2; the curvature radius R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: -0.75 < R2 / f < -0.3.

[0009] More preferably, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.5 < f2 / f < 0.9; the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -3 < f3 / f < -0.8.

[0010] More preferably, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3 < f4 / f < 2.3; the curvature radius R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -5 < R7 / f < -3.2; the curvature radius R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -1 < R8 / f < -0.6.

[0011] More preferably, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -3.2 < f7 / f < -1.3; the curvature radius R13 of the object side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -5.5 < R13 / f < -1.6; the curvature radius R14 of the image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: 1.8 < R14 / f < 4.3.

[0012] Further preferably, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 0.6 < f12 / f < 1.6; the combined focal length f345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: -180 < f345678 / f < -0.8.

[0013] Further preferably, the combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: 1.2 < f56 / f < 8; the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.25 < f5 / f6 < -0.65; the fifth lens and the sixth lens are glued together to form a glued lens.

[0014] Further preferably, the combined focal length f12 of the first lens and the second lens and the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: 0.6 < f12 / f1234 < 1.25; the combined focal length f56 of the fifth lens and the sixth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -7 < f56 / f5678 < -0.3.

[0015] The optical lens provided by the present invention uses eight lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power distributions, it can improve the imaging quality of the optical lens, reduce aberration, improve the imaging quality of the optical lens, and enable the lens to have one or more advantages such as long focal length, 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 easy to understand from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

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

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

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

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

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

[0022] Figure 7 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

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

[0024] Figure 9 Schematic diagram of the structure of the optical lens in Example 5 of the present invention.

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

[0026] Figure 11 Schematic diagram of the structure of the optical lens in Example 6 of the present invention.

[0027] Figure 12 This is the MTF curve of the optical lens in Example 6 of the present invention.

[0028] Figure 13 Schematic diagram of the structure of the optical lens in Example 7 of the present invention.

[0029] Figure 14 This is the MTF curve of the optical lens in Example 7 of the present invention.

[0030] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] The optical lens provided by an embodiment of the present invention includes eight lenses with optical power, which are, along the optical axis from the object side to the imaging surface, 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.

[0039] In some embodiments, the first lens may have a negative optical power, its object side may be concave, and its image side may be convex. The second lens may have a positive optical power, its object side may be convex, and its image side may be convex or concave. The third lens may have a negative optical power, its object side may be concave or convex, and its image side may be concave. The fourth lens may have a positive optical power, its object side may be concave, and its image side may be convex. The fifth lens may have a positive optical power, its object side may be convex, and its image side may be convex. The sixth lens may have a negative optical power, its object side may be concave, and its image side may be concave. The seventh lens may have a negative optical power, its object side may be concave, and its image side may be concave. The eighth lens may have a negative optical power, its object side may be concave or convex, and its image side may be convex or concave.

[0040] In some embodiments, the optical lens may further include an aperture, and the aperture may be located between the first lens and the second lens. It can be understood that the aperture is used to limit the amount of incident light to change the brightness of the imaging.

[0041] In some embodiments, the optical lens may further include a filter and a protective glass, which are sequentially arranged along the optical axis between the eighth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging. The protective glass plays a role in protecting the optical lens, preventing the photosensitive chip from being damaged, and can improve the anti-impact and scratch-resistant capabilities of the optical lens, while having almost no impact on the imaging quality of the optical lens.

[0042] In some embodiments, the fifth lens and the sixth lens may 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.

[0043] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy: -0.85 < f12 / f345678 < 0. Meeting the above range helps to correct the system chromatic aberration and improve the imaging performance. More specifically: -0.8 < f12 / f345678 < 0.

[0044] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.5 < TTL / f < 1.8; 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: 2.6 < TTL / IH < 3.2. Meeting the above ranges is beneficial to achieving the balance of a small volume and a large image plane of the optical lens, making the lens have a smaller total length. More specifically: 1.6 < TTL / f < 1.79; 2.8 < TTL / IH < 3.14.

[0045] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 0.5 < IH / f < 0.6; the clear aperture radius d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 3.8 < d1 / (IH / 2) / Tan(FOV / 2) < 4.5. Meeting the above ranges, controlling the image height and focal length of the optical lens within a reasonable range, helps the optical lens to have the characteristic of a large image plane and improve the imaging quality. At the same time, it can reasonably arrange the overall geometric shape of the optical lens and improve its structural stability. More specifically: 0.56 < IH / f < 0.59; 3.87 < d1 / (IH / 2) / Tan(FOV / 2) < 4.5.

[0046] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.9 < f1 / f < -1.2; the curvature radius R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: -0.5 < R1 / f < -0.2; the curvature radius R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: -0.75 < R2 / f < -0.3. Meeting the above ranges, reasonably limiting the proportion of the optical power of the first lens and its surface shape, can collect the light at the large field of view to a greater extent, make the light enter the rear optical system, increase the light flux and at the same time increase the field angle. More specifically: -1.75 < f1 / f < -1.29; -0.45 < R1 / f < -0.24; -0.69 < R2 / f < -0.37.

[0047] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.5 < f2 / f < 0.9; the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -3 < f3 / f < -0.8. Meeting the above ranges can effectively balance the aberration of the lens and improve the imaging quality. More specifically: 0.56 < f2 / f < 0.85; -2.85 < f3 / f < -0.85.

[0048] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3 < f4 / f < 2.3; 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: -5 < R7 / f < -3.2; 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: -1 < R8 / f < -0.6. Meeting the above ranges, by reasonably defining the proportion of the optical power of the fourth lens and its surface shape, spherical aberration can be optimized to achieve high-quality imaging. More specifically: 1.42 < f4 / f < 2.09; -4.55 < R7 / f < -3.53; -0.94 < R8 / f < -0.69.

[0049] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -3.2 < f7 / f < -1.3; the radius of curvature R13 of the object side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -5.5 < R13 / f < -1.6; the radius of curvature R14 of the image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: 1.8 < R14 / f < 4.3. Meeting the above ranges, by reasonably defining the proportion of the optical power of the seventh lens and its surface shape, the aberration generated at the front end of the lens can be effectively corrected, improving the imaging quality of the lens. More specifically: -2.92 < f7 / f < -1.43; -5.05 < R13 / f < -1.69; 1.91 < R14 / f < 4.

[0050] In some embodiments, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 0.6 < f12 / f < 1.6; the combined focal length f^345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: -180 < f^345678 / f < -0.8. Meeting the above ranges can reduce the difficulty of aberration correction of the lens and improve the imaging quality of the optical lens. More specifically: 0.68 < f12 / f < 1.47; -173.34 < f^345678 / f < -0.87.

[0051] In some embodiments, the combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: 1.2 < f56 / f < 8; the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.25 < f5 / f6 < -0.65; the fifth lens and the sixth lens are glued together to form a cemented lens. Meeting the above ranges can reduce the assembly sensitivity of the optical lens, thereby reducing the processing technology difficulty of the optical lens and improving the assembly yield. More specifically: 1.33 < f56 / f < 7.8; -1.16 < f5 / f6 < -0.69.

[0052] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens satisfy: 0.6 < f12 / f1234 < 1.25; the combined focal length f56 of the fifth lens and the sixth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy: -7 < f56 / f5678 < -0.3. Meeting the above ranges is beneficial to improving the field curvature, enabling all details of the entire picture to fall on the same focal plane. More specifically: 0.63 < f12 / f1234 < 1.16; -6.8 < f56 / f5678 < -0.31.

[0053] In some embodiments, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 18° < FOV / Fno < 19°. Meeting the above range and reasonably limiting the ratio of the field of view angle to the aperture value can collect light at large angles and obtain good imaging quality. More specifically: 18.3° < FOV / Fno < 18.4°.

[0054] In some embodiments, 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: 0.9 < IH / EPD < 1. Meeting the above range and reasonably limiting the ratio of the image height to the entrance pupil diameter is beneficial to increasing the light transmission amount, making the brightness of the peripheral field of view and the central field of view more uniform. More specifically: 0.96 < IH / EPD < 0.99.

[0055] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.15 < BFL / f < 0.28. 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.

[0056] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 0.4 < f5 / f < 0.6; the curvature radius R9 of the object side of the fifth lens and the effective focal length f of the optical lens satisfy: 0.6 < R9 / f < 1.5; the curvature radius R10 of the image side of the fifth lens and the effective focal length f of the optical lens satisfy: -0.55 < R10 / f < -0.35. Meeting the above ranges and reasonably limiting the light power ratio and surface shape of the fifth lens helps to smooth the light trend of the front-end lens, correct the aberration generated by the front-end lens, and improve the imaging quality. More specifically: 0.45 < f5 / f < 0.59; 0.62 < R9 / f < 1.45; -0.52 < R10 / f < -0.4. [[ID=..>

[0057] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -0.8 < f6 / f < -0.4. By satisfying the above range and reasonably limiting the proportion of the optical power of the sixth lens, the aberration of the marginal field of view can be effectively improved, and the overall imaging quality of the optical lens can be enhanced. More specifically: -0.78 < f6 / f < -0.42.

[0058] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -5.4 < f8 / f < -1. By satisfying the above range and reasonably limiting the proportion of the optical power of the eighth lens, spherical aberration and coma can be optimized, which is beneficial to high-resolution imaging. More specifically: -4.95 < f8 / f < -1.09.

[0059] In some embodiments, the curvature radius R1 of the object side surface of the first lens and the curvature radius R2 of the image side surface of the first lens satisfy: -0.3 < (R1 - R2) / (R1 + R2) < -0.1; 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: 0.5 < (R7 - R8) / (R7 + R8) < 0.8; the curvature radius R13 of the object side surface of the seventh lens and the curvature radius R14 of the image side surface of the seventh lens satisfy: |(R13 + R14) / (R13 - R14)| < 0.5. By satisfying the above range, the aberration of the optical lens can be corrected, and the light path passing through the first, fourth, and seventh lenses can be ensured to be stable, reducing the tolerance sensitivity of the optical lens. More specifically: -0.24 < (R1 - R2) / (R1 + R2) < -0.18; 0.58 < (R7 - R8) / (R7 + R8) < 0.7; -0.17 < (R13 + R14) / (R13 - R14) < 0.45.

[0060] In some embodiments, the optical lens satisfies the following conditional expressions: 20 mm < f < 22 mm; 30° < FOV < 32°; 12 mm < EPD < 13 mm; 33 mm < TTL < 38 mm; 1.5 < Fno < 1.9; 12 mm < IH < 12.5 mm; 21° < CRA < 26°; 3 mm < BFL < 6 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the overall optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the principal ray incident angle at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. Meeting the above ranges, the optical lens has at least one or more advantages such as long focal length, large aperture, and high imaging quality. More specifically: 20.93 mm < f < 21.29 mm; 31.1° < FOV < 31.3°; 12.31 mm < EPD < 12.53 mm; 33.9 mm < TTL < 37.87 mm; 1.65 < Fno < 1.75; 12 mm < IH < 12.2 mm; 21.21° < CRA < 25.1°; 3.26 mm < BFL < 5.71 mm.

[0061] 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 by the low dispersion characteristic of the glass itself. The optical lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0062] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving miniaturization of the lens. More specifically, the first lens, the second lens, and the eighth lens of the present invention adopt aspherical lenses, and the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens adopt spherical lenses.

[0063] 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, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients, respectively.

[0064] 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.

[0065] 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. The optical lens 100 includes, along the optical axis from the object side to the imaging surface, a first lens L1, an aperture ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter G1, and a protective glass G2.

[0066] The first lens L1 has negative refractive power, its object-side surface S1 is concave, and its image-side surface S2 is convex; The second lens L2 has positive refractive power, its object-side surface S3 is convex, and its image-side surface S4 is convex; The third lens L3 has negative refractive power, its object-side surface S5 is concave, and its image-side surface S6 is concave; The fourth lens L4 has positive refractive power, its object-side surface S7 is concave, and its image-side surface S8 is convex; The fifth lens L5 has positive refractive power, its object-side surface S9 is convex, and its image-side surface is convex; The sixth lens L6 has negative refractive power, its object-side surface is concave, and its image-side surface S11 is concave; The fifth lens L5 and the sixth lens L6 form a cemented lens group. That is, the cemented surface between the image-side surface of the fifth lens L5 and the object-side surface of the sixth lens L6 is S10. The seventh lens L7 has negative refractive power, its object-side surface S12 is concave, and its image-side surface S13 is concave; The eighth lens L8 has negative refractive power, its object-side surface S14 is concave, and its image-side surface S15 is convex; The object-side surface S16 and the image-side surface S17 of the filter G1 are both flat surfaces; The object side surface S18 and the image side surface S19 of the protective glass G2 are both flat surfaces; The imaging surface S20 is a plane.

[0067] The first lens L1, the second lens L2, and the eighth lens L8 are glass aspherical lenses, and the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are glass spherical lenses.

[0068] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0069] Table 1-1 The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0070] Table 1-2 In this embodiment, the MTF curve of the optical lens 100 is as follows: Figure 2 shown.

[0071] Figure 2 The MTF (Modulation Transfer Function) curve for Example 1 is shown. It represents 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 example is consistently above 0.5 across the entire field of view. Within the range of 0 to 160 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.

[0072] Example 2 See also Figure 3 , 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 S15 of the eighth lens L8 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0073] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0074] Table 2-1 The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0075] Table 2-2 In this embodiment, the MTF curve of the optical lens 200 is as follows: Figure 4 As shown. Figure 4 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 160 lp / mm, 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.

[0076] Example 3 See also Figure 5 , 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 mainly differs in that: the object-side surface S14 of the eighth lens L8 is convex, and the image-side surface S15 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0077] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0078] Table 3-1 The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0079] Table 3-2 In this embodiment, the MTF curve of the optical lens 300 is as follows: Figure 6 As shown. Figure 6 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 160 lp / mm, 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.

[0080] Example 4 See also Figure 7 , 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 S4 of the second lens L2 is concave; the object-side surface S14 of the eighth lens L8 is convex, and the image-side surface S15 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0081] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0082] Table 4-1 The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0083] Table 4-2 In this embodiment, the MTF curve of the optical lens 400 is as follows: Figure 8 As shown. Figure 8 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 160 lp / mm, 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.

[0084] Example 5 See also Figure 9 , 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 convex; the image-side surface S15 of the eighth lens L8 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0085] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0086] Table 5-1 The surface parameters of the aspheric lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0087] Table 5-2 In this embodiment, the MTF curve of the optical lens 500 is as follows: Figure 10 As shown. Figure 10 As can be seen, the MTF value of this embodiment is above 0.5 throughout the entire field of view. In the range of 0 to 160 lp / mm, 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.

[0088] Example 6 See also Figure 11 , 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 object-side surface S5 of the third lens L3 is convex; the object-side surface S14 of the eighth lens L8 is convex, and the image-side surface S15 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0089] The relevant parameters of each lens in the optical lens 600 in Example 6 are shown in Table 6-1.

[0090] Table 6-1 The surface parameters of the aspheric lens of the optical lens 600 in Example 6 are shown in Table 6-2.

[0091] Table 6-2 In this embodiment, the MTF curve of the optical lens 600 is as follows: Figure 12 As shown. Figure 12 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 160 lp / mm, 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.

[0092] Example 7 See also Figure 13 , shown is a schematic structural diagram of an optical lens 700 provided in Example 7 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image-side surface S4 of the second lens element L2 is concave; the object-side surface S5 of the third lens element L3 is convex; the image-side surface S15 of the eighth lens element L8 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0093] The relevant parameters of each lens in the optical lens 700 in Example 7 are shown in Table 7-1.

[0094] Table 7-1 The surface parameters of the aspheric lens of the optical lens 700 in Example 7 are shown in Table 7-2.

[0095] Table 7-2 In this embodiment, the MTF curve of the optical lens 700 is as follows: Figure 14 As shown. Figure 14 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 160 lp / mm, 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.

[0096] Please refer to Table 8-1 and Table 8-2, which show the optical characteristics corresponding to the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, chief ray incidence angle CRA at maximum image height, real image height IH corresponding to maximum field of view angle, maximum field of view angle FOV, entrance pupil diameter EPD, back focal length BFL of the optical lens, and the numerical value corresponding to each conditional expression in each embodiment.

[0097] Table 8-1 Table 8-2 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 long focus, large aperture, and high imaging quality.

[0098] 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.

[0099] 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 having optical power, 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 concave and whose image side is convex; A second lens with a positive optical power, whose object side is convex; A third lens with a negative optical power, whose image side is concave; A fourth lens with a positive optical power, whose object side is concave 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 negative optical power, whose object side is concave and whose image side is concave; An eighth lens with a negative optical power; Wherein, the combined focal length f12 of the first lens and the second lens and the combined focal length f345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -$0.85 \lt f12 / f345678 \lt 0$.

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: $1.5 \lt TTL / f \lt 1.8$; 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: $2.6 \lt TTL / IH \lt 3.2$.

3. 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: $0.5 \lt IH / f \lt 0.6$; 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: $3.8 \lt d1 / (IH / 2) / Tan(FOV / 2) \lt 4.5$.

4. The optical lens according to claim 1, wherein: The focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -$1.9 \lt f1 / f \lt -1.2$; the curvature radius R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: -$0.5 \lt R1 / f \lt -0.2$; the curvature radius R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: -$(-0.75 \lt R2 / f \lt -0.3$.

5. The optical lens according to claim 1, wherein: The focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: $0.5 \lt f2 / f \lt 0.9$; the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -$3 \lt f3 / f \lt -0.8$.

6. The optical lens according to claim 1, wherein: The focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: $1.3 \lt f4 / f \lt 2.3$; the curvature radius R7 of the object side of the fourth lens and the effective focal length f of the optical lens satisfy: -$5 \lt R7 / f \lt -3.2$; the curvature radius R8 of the image side of the fourth lens and the effective focal length f of the optical lens satisfy: -$1 \lt R8 / f \lt -0.6$.

7. The optical lens according to claim 1, wherein: The focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -3.2 < f7 / f < -1.3; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -5.5 < R13 / f < -1.6; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.8 < R14 / f < 4.

3.

8. The optical lens according to claim 1, wherein: The combined focal length f12 of the first lens and the second lens and the effective focal length f of the optical lens satisfy: 0.6 < f12 / f < 1.6; the combined focal length f345678 of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: -180 < f345678 / f < -0.

8.

9. The optical lens according to claim 1, wherein: The combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: 1.2 < f56 / f < 8; the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.25 < f5 / f6 < -0.

65.

10. The optical lens according to claim 1, wherein: The combined focal length f12 of the first lens and the second lens and the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: 0.6 < f12 / f1234 < 1.25; the combined focal length f56 of the fifth lens and the sixth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -7 < f56 / f5678 < -0.3.

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