Optical lens

Abstract

This invention provides an optical lens comprising eight lenses of optical power, arranged sequentially along the optical axis from the object side to the image plane: a first lens with negative optical power, its object side being convex and its image side being concave; a second lens with negative optical power, its object side being convex and its image side being concave; a third lens with negative optical power, its object side being convex near the optical axis and its image side being concave; a fourth lens with positive optical power; a fifth lens with positive optical power, its object side being convex and its image side being convex; a sixth lens with positive optical power; a seventh lens with negative optical power; and an eighth lens with positive optical power, its object side being convex and its image side being convex. The optical lens provided by this invention has one or more advantages, such as short focal length, large field of view, and high image quality.

Description

Technical Field

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

[0002] Fisheye lenses offer ultra-wide-angle shooting capabilities, capturing a wider range of scenes and satisfying the need for shooting large-scale scenarios. Therefore, they are widely used in action cameras, drones, panoramic surveillance, and other video recording applications. However, existing fisheye lens devices still have several shortcomings, such as the increased field of view leading to difficulties in aberration correction and decreased image quality; and their long and bulky size. Therefore, there is a need to develop an optical lens with one or more advantages, including a large field of view, high image quality, and small size, to better meet market demands. Summary of the Invention

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

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

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

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

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

[0008] The third lens with negative optical power has a convex object-side surface near the optical axis and a concave image-side surface.

[0009] A fourth lens with positive optical power;

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

[0011] A sixth lens with positive optical power;

[0012] A seventh lens with negative optical power;

[0013] The eighth lens with positive optical power has a convex object-side surface and a convex image-side surface.

[0014] Among them, the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: 0 < (R5 - R6) / (R5 + R6) < 0.9; 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: -1 < (R15 + R16) / (R15 - R16) < -0.1.

[0015] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 18 < TTL / f < 31; 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: 6 < TTL / IH < 15.

[0016] Further preferably, the maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 85° < FOV / Fno < 120°; the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4 < IH / EPD < 7.8.

[0017] Further preferably, the true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2 < IH / f < 3.5; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.6 < BFL / f < 3.4.

[0018] Further preferably, the total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 18 < 180°×TTL / (IH / 2) / (FOV / 2) < 45; the half clear aperture d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: -8.5 < d1 / (IH / 2) / Tan(FOV / 2) < -2.3.

[0019] Further preferably, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -6.3 < f2 / f < -3.1; the curvature radius R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: 10 < R3 / f < 100; the curvature radius R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: 2.3 < R4 / f < 4.

[0020] More preferably, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy -300 < f3 / f < -6.5; the radius of curvature R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy 4 < R5 / f < 69; the radius of curvature R6 of the image side surface of the third lens and the effective focal length f of the optical lens satisfy 2.3 < R6 / f < 7.5.

[0021] More preferably, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy 3 < f5 / f < 7; the radius of curvature R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy 4 < R9 / f < 12; the radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy -7.5 < R10 / f < -2.5.

[0022] More preferably, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy 4 < f8 / f < 39; the radius of curvature R15 of the object side surface of the eighth lens and the effective focal length f of the optical lens satisfy 2.5 < R15 / f < 39; the radius of curvature R16 of the image side surface of the eighth lens and the effective focal length f of the optical lens satisfy -90 < R16 / f < -14.

[0023] More preferably, the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the effective focal length f of the optical lens satisfy -45 < f1234 / f < -3.1; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy 2.4 < f5678 / f < 4.3.

[0024] 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 aberrations, and enhance the imaging quality of the optical lens, enabling the lens to have one or more advantages such as short focal length, large field angle, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, where:

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

[0027] Figure 2 is a MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0029] Figure 4 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0030] Figure 5 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0031] Figure 6 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0032] Figure 7 This is a schematic diagram of the optical lens structure in Embodiment 4 of the present invention.

[0033] Figure 8 This is the MTF curve of the optical lens in Embodiment 4 of the present invention.

[0034] Figure 9 This is a schematic diagram of the optical lens structure in Embodiment 5 of the present invention.

[0035] Figure 10 This is the MTF curve of the optical lens in Embodiment 5 of the present invention.

[0036] Figure 11 This is a schematic diagram of the optical lens in Embodiment 6 of the present invention.

[0037] Figure 12 This is the MTF curve of the optical lens in Embodiment 6 of the present invention.

[0038] Figure 13 This is a schematic diagram of the optical lens in Embodiment 7 of the present invention.

[0039] Figure 14 This is the MTF curve of the optical lens in Embodiment 7 of the present invention.

[0040] Figure 15 This is a schematic diagram of the optical lens in Embodiment 8 of the present invention.

[0041] Figure 16 This is the MTF curve of the optical lens in Embodiment 8 of the present invention.

[0042] Figure 17 This is a schematic diagram of the optical lens structure in Embodiment 9 of the present invention.

[0043] Figure 18 This is the MTF curve of the optical lens in Embodiment 9 of the present invention.

[0044] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0045] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0046] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0047] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0048] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0049] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0050] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] The optical lens provided in this embodiment of the invention includes eight lenses with optical power, which are arranged sequentially from the object side to the imaging plane along the optical axis as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

[0053] In some embodiments, the first lens may have negative optical power, its object-side surface may be convex, and its image-side surface may be concave. The second lens may have negative optical power, its object-side surface may be convex, and its image-side surface may be concave. The third lens may have negative optical power, its object-side surface may be convex near the optical axis, and its image-side surface may be concave. The fourth lens may have positive optical power, its object-side surface may be convex or concave, and its image-side surface may be convex or concave. The fifth lens may have positive optical power, its object-side surface may be convex, and its image-side surface may be convex. The sixth lens may have positive optical power, its object-side surface may be convex or concave, and its image-side surface may be convex or concave. The seventh lens may have negative optical power, its object-side surface may be concave or convex, and its image-side surface may be concave or convex. The eighth lens may have positive optical power, its object-side surface may be convex, and its image-side surface may be convex.

[0054] In some embodiments, the optical lens may also include an aperture stop, which may be located between the fourth and fifth lenses. It is understood that the aperture stop is used to limit the amount of light entering the lens, thereby altering the brightness of the image.

[0055] In some embodiments, the optical lens may further include a filter disposed along the optical axis between the eighth lens and the imaging plane. The filter is used to filter out interfering light and prevent it from reaching the imaging plane of the optical lens and affecting normal imaging.

[0056] In some embodiments, the sixth and seventh lenses can be cemented together to form a cemented lens, which can effectively correct chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberrations of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0057] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 0 < (R5 - R6) / (R5 + R6) < 0.9; 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: -1 < (R15 + R16) / (R15 - R16) < -0.1. Satisfying the above ranges is beneficial to adjusting the light path and endowing the optical lens with the characteristic of a large field angle. More specifically: 0.06 < (R5 - R6) / (R5 + R6) < 0.84; -0.95 < (R15 + R16) / (R15 - R16) < -0.19.

[0058] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 18 < TTL / f < 31; 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: 6 < TTL / IH < 15. Satisfying the above ranges can effectively limit the length of the lens and is beneficial to the miniaturization of the optical lens. More specifically: 18.58 < TTL / f < 29.9; 6.14 < TTL / IH < 13.73.

[0059] In some embodiments, the maximum field angle FOV of the optical lens and the f-number Fno of the optical lens satisfy: 85° < FOV / Fno < 120°; the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4 < IH / EPD < 7.8. Satisfying the above ranges can reasonably limit the ratio of the field angle to the f-number, which is beneficial to increasing the light input of the lens and enabling the lens to achieve high-definition imaging in a dim environment. At the same time, reasonably limiting the ratio of the image height to the entrance pupil diameter is beneficial to increasing the light throughput and making the brightness of the peripheral field and the central field more uniform. More specifically: 91.66° < FOV / Fno < 110.1°; 4.38 < IH / EPD < 7.11.

[0060] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2 < IH / f < 3.5; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.6 < BFL / f < 3.4. Satisfying the above ranges can achieve a larger field angle and ensure a large depth of field. At the same time, limiting the optical lens to have an appropriate back focus is convenient for reasonably arranging the positions of each lens and reducing the processing and assembly difficulty. More specifically: 2.11 < IH / f < 3.24; 1.7 < BFL / f < 3.17.

[0061] In some embodiments, the total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 18 < 180°×TTL / (IH / 2) / (FOV / 2) < 45; the half clear aperture d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: -8.5 < d1 / (IH / 2) / Tan(FOV / 2) < -2.3. Meeting the above ranges is beneficial to balancing the relationship among the total length, image height, and field angle of the optical lens. At the same time, it can reasonably arrange the overall geometric shape of the optical lens and improve its structural stability. More specifically: 18.43 < 180°×TTL / (IH / 2) / (FOV / 2) < 44.92; -7.92 < d1 / (IH / 2) / Tan(FOV / 2) < -2.55.

[0062] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -6.3 < f2 / f < -3.1; 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: 10 < R3 / f < 100; 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: 2.3 < R4 / f < 4. Meeting the above ranges and reasonably limiting the proportion of the optical power of the second lens and its surface shape can further diverge light and increase the field angle of the imaging system. More specifically: -5.92 < f2 / f < -3.4; 10.42 < R3 / f < 91.38; 2.48 < R4 / f < 3.88.

[0063] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -300 < f3 / f < -6.5; the radius of curvature R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy: 4 < R5 / f < 69; the radius of curvature R6 of the image side surface of the third lens and the effective focal length f of the optical lens satisfy: 2.3 < R6 / f < 7.5. Meeting the above ranges and reasonably limiting the proportion of the optical power of the third lens and its surface shape is beneficial to adjusting the light path of the light from the first lens and the second lens, making the marginal light continue to diverge after passing through the third lens, and correcting the marginal field aberration. More specifically: -292.43 < f3 / f < -7.01; 4.16 < R5 / f < 62.44; 2.56 < R6 / f < 7.01.

[0064] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 3 < f5 / f < 7; the radius of curvature R9 of the object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 4 < R9 / f < 12; the radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -7.5 < R10 / f < -2.5. Meeting the above ranges reasonably limits the proportion of the optical power and the surface shape of the fifth lens. In cooperation with the fourth lens, it further restricts the light ray trend and balances the aberration. More specifically: 3.12 < f5 / f < 6.77; 4.12 < R9 / f < 11.08; -7.02 < R10 / f < -2.66.

[0065] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 4 < f8 / f < 39; the radius of curvature R15 of the object side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 2.5 < R15 / f < 39; the radius of curvature R16 of the image side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -90 < R16 / f < -14. Meeting the above ranges reasonably limits the proportion of the optical power and the surface shape of the eighth lens, which is beneficial to reducing the eccentricity sensitivity of the optical lens and improving the imaging resolution. More specifically: 4.33 < f8 / f < 35.66; 2.6 < R15 / f < 36.1; -84.91 < R16 / f < -15.49.

[0066] In some embodiments, the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: -45 < f1234 / f < -3.1; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 2.4 < f5678 / f < 4.3. Meeting the above ranges, respectively limiting the proportion of the optical power of the front diaphragm lens group and the proportion of the optical power of the rear diaphragm lens group is beneficial to correcting the chromatic aberration and field curvature of the optical system, reducing the sensitivity, and reducing the lens forming difficulty. More specifically: -41.51 < f1234 / f < -3.4; 2.66 < f5678 / f < 3.97.

[0067] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -29 < f1 / f < -7. Meeting the above range reasonably limits the proportion of the optical power of the first lens, can collect the light rays at the large field of view to a large extent, make the light rays enter the rear optical system, and increase the light flux while increasing the field angle. More specifically: -26.61 < f1 / f < -7.69.

[0068] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 5 < f4 / f < 14. By satisfying the above range and reasonably limiting the proportion of the optical power of the fourth lens, the light can be converged and the aberration problem caused by the first three negative focal length lenses can be corrected. More specifically: 5.26 < f4 / f < 13.24.

[0069] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 1.6 < f6 / f < 15. By satisfying the above range and reasonably limiting the proportion of the optical power of the sixth lens, the aberration of the edge field of view can be effectively improved, and the overall imaging quality of the optical lens can be enhanced. More specifically: 1.78 < f6 / f < 14.74.

[0070] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -4.5 < f7 / f < -1.5. By satisfying the above range and reasonably limiting the proportion of the optical power of the seventh lens, the aberration generated at the front end of the lens can be effectively corrected, and the imaging quality of the lens can be improved. More specifically: -4.1 < f7 / f < -1.63.

[0071] In some embodiments, the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -13.5 < f1234 / f5678 < -0.9. By satisfying the above range and reasonably limiting the focal length relationship between the lens groups before and after the aperture stop, it helps the smooth transition of light, expands the field angle of the optical lens, and improves the imaging quality of the optical lens. More specifically: -12.54 < f12{34} / f5678 < -1.02.

[0072] In some embodiments, the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: 0.4 < (R1 - R2) / (R1 + R2) < 0.7. By satisfying the above range, the aberration of the optical lens can be corrected, and the tolerance sensitivity of the optical lens can be reduced. More specifically: 0.45 < (R1 - R2) / (R1 + R2) < 0.67.

[0073] In some embodiments, the object-side curvature radius R3 of the second lens and the image-side curvature radius R4 of the second lens satisfy: 0.55 < (R3 - R4) / (R3 + R4) < 1. By satisfying the above range, the light can be further diverged, and the field angle of the imaging system can be increased. More specifically: 0.6 < (R3 - R4) / (R3 + R4) < 0.94.

[0074] In some embodiments, the optical lens satisfies the following conditional expressions: 0.5 mm < f < 0.85 mm; 210° < FOV < 250°; 0.2 mm < EPD < 0.45 mm; 14 mm < TTL < 19 mm; 1.9 < Fno < 2.5; 1.1 mm < IH < 2.7 mm; 10° < CRA < 23°; 1.3 mm < BFL < 2.7 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the 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 short focal length, large field of view angle, and high imaging quality. More specifically: 0.54 mm < f < 0.81 mm; 219° < FOV < 241°; 0.24 mm < EPD < 0.41 mm; 14.88 mm < TTL < 18.01 mm; 1.99 < Fno < 2.41; 1.18 mm < IH < 2.59 mm; 10.26° < CRA < 22.64°; 1.36 mm < BFL < 2.54 mm.

[0075] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The first lens, second lens, fourth lens, sixth lens, seventh lens, and eighth lens in the optical lens provided by the present invention can adopt glass materials, and the third lens and fifth lens can adopt plastic materials. Adopting a glass-plastic hybrid structure can effectively reduce costs, correct aberrations, reduce the volume, improve the thermal stability performance, and provide an optical lens product with higher cost performance.

[0076] In some embodiments, the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the first lens, second lens, fourth lens, sixth lens, seventh lens, and eighth lens of the present invention adopt spherical lenses, and the third lens and fifth lens adopt aspherical lenses.

[0077] 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 equations:

[0078] ;

[0079] Where z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the quadratic surface coefficient, and B, C, D, E, F, G, and H are the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth order surface coefficients, respectively.

[0080] The present invention will be further described below with reference to several embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different; for specific differences, please refer to the parameter tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

[0081] Example 1

[0082] Please see Figure 1 The diagram shows a schematic of the structure of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 includes, along the optical axis from the object side to the imaging plane, the following components in sequence: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0083] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0084] The second lens L2 has negative optical power, its object side S3 is convex, and its image side S4 is concave.

[0085] The third lens L3 has negative optical power, its object side S5 is convex near the optical axis, and its image side S6 is concave.

[0086] The fourth lens L4 has positive optical power, its object side S7 is convex, and its image side S8 is convex.

[0087] The fifth lens L5 has positive optical power, its object side S9 is convex, and its image side S10 is convex.

[0088] The sixth lens L6 has positive optical power, its object-side surface S11 is convex, and its image-side surface is convex.

[0089] The seventh lens L7 has negative optical power, its object side is concave, and its image side S13 is concave.

[0090] The sixth lens L6 and the seventh lens L7 form a cemented lens group, that is, the cementing surface of the image side of the sixth lens L6 and the object side of the seventh lens L7 is S12.

[0091] The eighth lens L8 has positive optical power, its object side S14 is convex, and its image side S15 is convex.

[0092] The object-side surface S16 and the image-side surface S17 of filter G1 are both planar.

[0093] The imaging plane S18 is a plane.

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

[0095] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0096] Table 1-1

[0097]

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

[0099] Table 1-2

[0100]

[0101] In this embodiment, the MTF curve of the optical lens 100 is as follows: Figure 2 As shown.

[0102] Figure 2 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in various fields of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents MTF value. As can be seen from the figure, the MTF value of this example is above 0.4 throughout the entire field of view. Within the range of 0–160 lp / mm, the MTF curve decreases smoothly and uniformly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies.

[0103] Example 2

[0104] Please see Figure 3 The figure shows a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The main difference between this embodiment and Embodiment 1 is that the image side surface S8 of the fourth lens L4 is concave; the optical parameters such as the radius of curvature and lens thickness of each lens surface 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 profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0109] Table 2-2

[0110]

[0111] In this embodiment, the MTF curve of the optical lens 200 is as follows: Figure 4 As shown. From Figure 4 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 smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0112] Example 3

[0113] Please see Figure 5 The figure shows a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side S7 of the fourth lens L4 is concave, the image side S13 of the seventh lens L7 is convex, and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0114] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0115] Table 3-1

[0116]

[0117] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0118] Table 3-2

[0119]

[0120] In this embodiment, the MTF curve of the optical lens 300 is as follows: Figure 6 As shown. From Figure 6As can be seen, the MTF value of this embodiment is above 0.7 throughout the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0121] Example 4

[0122] Please see Figure 7 The figure shows a schematic diagram of the structure of the optical lens 400 provided in Embodiment 4 of the present invention. The main difference between this embodiment and Embodiment 1 is that the image-side surface S8 of the fourth lens L4 is concave and the image-side surface S13 of the seventh lens L7 is convex. The optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0123] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0124] Table 4-1

[0125]

[0126] The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0127] Table 4-2

[0128]

[0129] In this embodiment, the MTF curve of the optical lens 400 is as follows: Figure 8 As shown. From Figure 8 As can be seen, the MTF value of this embodiment is above 0.6 throughout the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0130] Example 5

[0131] Please see Figure 9 The figure shown is a schematic diagram of the structure of the optical lens 500 provided in Embodiment 5 of the present invention. The main difference between this embodiment and Embodiment 1 is that the image side surface S12 of the sixth lens L6 is concave and the object side surface S12 of the seventh lens L7 is convex. The optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0132] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0133] Table 5-1

[0134]

[0135] The surface profile parameters of the aspherical lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0136] Table 5-2

[0137]

[0138] In this embodiment, the MTF curve of the optical lens 500 is as follows: Figure 10 As shown. From 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 smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0139] Example 6

[0140] Please see Figure 11 The figure shows a schematic diagram of the structure of the optical lens 600 provided in Embodiment 6 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object-side surface S7 of the fourth lens L4 is concave; the object-side surface S11 of the sixth lens L6 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0141] The relevant parameters of each lens in the optical lens 600 in Example 6 are shown in Table 6-1.

[0142] Table 6-1

[0143]

[0144] The surface profile parameters of the aspherical lens of the optical lens 600 in Example 6 are shown in Table 6-2.

[0145] Table 6-2

[0146]

[0147] In this embodiment, the MTF curve of the optical lens 600 is as follows: Figure 12 As shown. From Figure 12 As can be seen, the MTF value of this embodiment is above 0.6 throughout the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0148] Example 7

[0149] Please see Figure 13The figure shown is a schematic diagram of the structure of the optical lens 700 provided in Embodiment 7 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S11 of the sixth lens L6 is concave; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0150] The relevant parameters of each lens in the optical lens 700 in Example 7 are shown in Table 7-1.

[0151] Table 7-1

[0152]

[0153] The surface profile parameters of the aspherical lens of the optical lens 700 in Example 7 are shown in Table 7-2.

[0154] Table 7-2

[0155]

[0156] In this embodiment, the MTF curve of the optical lens 700 is as follows: Figure 14 As shown. From Figure 14 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 smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0157] Example 8

[0158] Please see Figure 15 The figure shown is a schematic diagram of the structure of the optical lens 800 provided in Embodiment 8 of the present invention. The main difference between this embodiment and Embodiment 1 is that the image side S8 of the fourth lens L4 is concave; the object side S11 of the sixth lens L6 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0159] The relevant parameters of each lens in the optical lens 800 in Example 8 are shown in Table 8-1.

[0160] Table 8-1

[0161]

[0162] The surface profile parameters of the aspherical lens of the optical lens 800 in Example 8 are shown in Table 8-2.

[0163] Table 8-2

[0164]

[0165] In this embodiment, the MTF curve of the optical lens 800 is as follows: Figure 16 As shown. From Figure 16 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 smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0166] Example 9

[0167] Please see Figure 17 The figure shown is a schematic diagram of the structure of the optical lens 900 provided in Embodiment 9 of the present invention. The main difference between this embodiment and Embodiment 1 is that: the image-side surface S8 of the fourth lens L4 is concave; the image-side surface S12 of the sixth lens L6 is concave; the object-side surface S12 of the seventh lens L7 is convex; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0168] The relevant parameters of each lens in the optical lens 900 in Example 9 are shown in Table 9-1.

[0169] Table 9-1

[0170]

[0171] The surface profile parameters of the aspherical lens of the optical lens 900 in Example 9 are shown in Table 9-2.

[0172] Table 9-2

[0173]

[0174] In this embodiment, the MTF curve of the optical lens 900 is as follows: Figure 18 As shown. From Figure 18 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 smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0175] Please refer to Tables 10-1 and 10-2 for the optical characteristics corresponding to the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, principal ray incident angle CRA at maximum image height, true image height IH corresponding to maximum field of view, maximum field of view FOV, entrance pupil diameter EPD, back focal length BFL, and the values ​​corresponding to each conditional expression in each embodiment.

[0176] Table 10-1

[0177]

[0178] Table 10-2

[0179]

[0180] In summary, the optical lens provided by the present invention employs eight lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as short focal length, large field of view, and high imaging quality.

[0181] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0182] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An optical lens, eight pieces of lenses with optical power, characterized in that, In order from the object side to the imaging plane along the optical axis, successively comprise: a first lens with negative refractive power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; a second lens with negative refractive power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; a third lens with negative refractive power, the object side surface of which is a convex surface at the near optical axis, and the image side surface of which is a concave surface; a fourth lens with positive refractive power; a fifth lens with positive refractive power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; a sixth lens with positive refractive power; a seventh lens with negative refractive power; an eighth lens with positive refractive power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; wherein the object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: 0 < (R5-R6) / (R5+R6) < 0.9; the object side surface curvature radius R15 of the eighth lens and the image side surface curvature radius R16 of the eighth lens satisfy: -1 < (R15+R16) / (R15-R16) < -0.1; the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 18 < TTL / f < 31; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 6 < TTL / IH < 15.

2. The optical lens of claim 1, wherein, The object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: 0.06 < (R5-R6) / (R5+R6) < 0.84; the object side surface curvature radius R15 of the eighth lens and the image side surface curvature radius R16 of the eighth lens satisfy: -0.95 < (R15+R16) / (R15-R16) < -0.19; the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 18.58 < TTL / f < 29.9; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 6.14 < TTL / IH < 13.

73.

3. The optical lens of claim 1, wherein, The maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 85° < FOV / Fno < 120°; the real image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4 < IH / EPD < 7.

8.

4. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2 < IH / f < 3.5; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.6 < BFL / f < 3.

4.

5. The optical lens of claim 1, wherein, An optical total length TTL of the optical lens, a real image height IH corresponding to a maximum field of view angle of the optical lens, and a maximum field of view angle FOV of the optical lens satisfy: 18 < 180° x TTL / (IH / 2) / (FOV / 2) < 45; a half light passing radius d1 of an object side surface of the first lens, the real image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: -8.5 < d1 / (IH / 2) / Tan(FOV / 2) < -2.

3.

6. The optical lens of claim 1, wherein, A focal length f2 of the second lens and an effective focal length f of the optical lens satisfy: -6.3 < f2 / f < -3.1; a radius of curvature R3 of an object side surface of the second lens and the effective focal length f of the optical lens satisfy: 10 < R3 / f < 100; a radius of curvature R4 of an image side surface of the second lens and the effective focal length f of the optical lens satisfy: 2.3 < R4 / f < 4.

7. The optical lens of claim 1, wherein, A focal length f3 of the third lens and an effective focal length f of the optical lens satisfy: -300 < f3 / f < -6.5; a radius of curvature R5 of an object side surface of the third lens and the effective focal length f of the optical lens satisfy: 4 < R5 / f < 69; a radius of curvature R6 of an image side surface of the third lens and the effective focal length f of the optical lens satisfy: 2.3 < R6 / f < 7.

5.

8. The optical lens of claim 1, wherein, A focal length f5 of the fifth lens and an effective focal length f of the optical lens satisfy: 3 < f5 / f < 7; a radius of curvature R9 of an object side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 4 < R9 / f < 12; a radius of curvature R10 of an image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -7.5 < R10 / f < -2.

5.

9. The optical lens of claim 1, wherein, A focal length f8 of the eighth lens and an effective focal length f of the optical lens satisfy: 4 < f8 / f < 39; a radius of curvature R15 of an object side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 2.5 < R15 / f < 39; a radius of curvature R16 of an image side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -90 < R16 / f < -14.

10. The optical lens of claim 1, wherein, A combined focal length f1234 of the first lens, the second lens, the third lens, and the fourth lens and an effective focal length f of the optical lens satisfy: -45 < f1234 / f < -3.1; a combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens, and the eighth lens and the effective focal length f of the optical lens satisfy: 2.4 < f5678 / f < 4.3.

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