Optical lens

Abstract

The application provides an optical lens which is composed of eight lenses and sequentially comprises, along an optical axis from an object side to an imaging surface, a first lens with negative focal power, the object side of which is a convex surface and the image side of which is a concave surface; a second lens with negative focal power, the object side of which is a convex surface and the image side of which is a concave surface; a third lens with positive focal power, the object side of which is a convex surface and the image side of which is a concave surface; a fourth lens with negative focal power, the object side of which is a convex surface and the image side of which is a concave surface; a fifth lens with positive focal power, the object side of which is a convex surface and the image side of which is a convex surface near the optical axis; a sixth lens with negative focal power, the image side of which is a concave surface; a seventh lens with positive focal power, the object side of which is a convex surface and the image side of which is a convex surface; and an eighth lens with negative focal power, the object side of which is a concave surface. The optical lens provided by the application has one or more advantages such as a large field of view, a large aperture, high imaging quality and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of imaging lenses, in particular to an optical lens. BACKGROUND

[0002] The law enforcement instrument is mainly used for digital recording of the scene in the law enforcement process, such as video shooting, photographing, audio recording, etc., so as to provide effective scene image data after the event. In the process of on-site law enforcement, law enforcement personnel need to record a larger range and clear image, however, the lens of the law enforcement instrument on the market either records unclear images or has too small a field of view and cannot record too many pictures.

[0003] Therefore, how to make the lens of the law enforcement instrument meet high imaging quality is a problem to be solved at present. SUMMARY

[0004] In view of the above problems, the purpose of the present application is to provide an optical lens, which has the advantages of excellent imaging quality.

[0005] The technical scheme adopted by the present application is:

[0006] An optical lens is composed of eight lenses, characterized in that, along the optical axis from the object side to the imaging surface, it comprises in sequence:

[0007] A first lens with negative focal power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface;

[0008] A second lens with negative focal power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface;

[0009] A third lens with positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface;

[0010] A fourth lens with negative focal power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface;

[0011] A fifth lens with positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface near the optical axis;

[0012] A sixth lens with negative focal power, the image side surface of which is a concave surface;

[0013] A seventh lens with positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface;

[0014] An eighth lens with negative focal power, the object side surface of which is a concave surface;

[0015] Wherein, the object side surface curvature radius R3 of the second lens and the image side surface curvature radius R4 of the second lens satisfy: 0.2 < (R3-R4) / (R3+R4) < 0.8, the object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: -1 < (R5-R6) / (R5+R6) < -0.2.

[0016] Further preferably, the total track length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.5 < TTL / f < 7.5; the total track length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.4 < TTL / IH < 3.6.

[0017] Further preferably, the maximum field angle FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 45° < FOV / FNO < 95°; 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: 3.4 < IH / EPD < 5.

[0018] Further preferably, 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: 1.7 < IH / f < 2.5; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.3 < BFL / f < 1.7.

[0019] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.7 < f1 / f < -1.1, the effective focal length f of the optical lens and the object side surface curvature radius R1 of the first lens satisfy: 7 < R1 / f < 88, the effective focal length f of the optical lens and the image side surface curvature radius R2 of the first lens satisfy: 0.8 < R2 / f < 1.3.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -23 < f2 / f < -4.3, the effective focal length f of the optical lens and the object side surface curvature radius R3 of the second lens satisfy: 6.2 < R3 / f < 21, the effective focal length f of the optical lens and the image side surface curvature radius R4 of the second lens satisfy: 2.5 < R4 / f < 4.9.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2.9 < f3 / f < 5.3, the effective focal length f of the optical lens and the object side surface curvature radius R5 of the third lens satisfy: 1.3 < R5 / f < 2.3, the effective focal length f of the optical lens and the image side surface curvature radius R6 of the third lens satisfy: 2.6 < R6 / f < 500.

[0022] It is further preferred that the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.7 < f6 / f < -1.2, and the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 0.8 < f7 / f < 1.1.

[0023] It is further preferred that the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -5.7 < f8 / f < -3, and the combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -1.7 < f123 / f45678 < -0.9.

[0024] It is further preferred that the object side surface curvature radius R1 of the first lens and the image side surface curvature radius R2 of the first lens satisfy: 0.7 < (R1-R2) / (R1+R2) < 1, and the object side surface curvature radius R13 of the seventh lens and the image side surface curvature radius R14 of the seventh lens satisfy: -0.5 < (R13+R14) / (R13-R14) < -0.1.

[0025] Compared with the prior art, the optical lens provided by the application adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved, so that the lens has one or more advantages of large field of view, large aperture, high imaging quality and the like. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the following drawings, in which:

[0027] Figure 1 FIG. 1 is a structural schematic diagram of an optical lens according to an embodiment of the present application.

[0028] Figure 2 FIG. 2 is an F-Tan(Theta) distortion curve diagram of the optical lens according to the embodiment of the present application.

[0029] Figure 3 FIG. 3 is an axial aberration curve diagram of the optical lens according to the embodiment of the present application.

[0030] Figure 4 FIG. 4 is a curve diagram of the optical lens according to the embodiment of the present application.

[0031] Figure 5 FIG. 5 is an MTF curve diagram of the optical lens according to the embodiment of the present application.

[0032] Figure 6 FIG. 6 is a relative luminance curve diagram of the optical lens according to the embodiment of the present application.

[0033] Figure 7 Structure diagram of optical lens in embodiment 2 of the present application.

[0034] Figure 8 F-Tan(Theta) distortion curve diagram of optical lens in embodiment 2 of the present application.

[0035] Figure 9 Axial aberration curve diagram of optical lens in embodiment 2 of the present application.

[0036] Figure 10 Axial aberration curve diagram of optical lens in embodiment 2 of the present application.

[0037] Figure 11 MTF curve diagram of optical lens in embodiment 2 of the present application.

[0038] Figure 12 Relative luminance curve diagram of optical lens in embodiment 2 of the present application.

[0039] Figure 13 Structure diagram of optical lens in embodiment 3 of the present application.

[0040] Figure 14 F-Tan(Theta) distortion curve diagram of optical lens in embodiment 3 of the present application.

[0041] Figure 15 Axial aberration curve diagram of optical lens in embodiment 3 of the present application.

[0042] Figure 16 Axial aberration curve diagram of optical lens in embodiment 3 of the present application.

[0043] Figure 17 MTF curve diagram of optical lens in embodiment 3 of the present application.

[0044] Figure 18 Relative luminance curve diagram of optical lens in embodiment 3 of the present application.

[0045] Figure 19 Structure diagram of optical lens in embodiment 4 of the present application.

[0046] Figure 20 F-Tan(Theta) distortion curve diagram of optical lens in embodiment 4 of the present application.

[0047] Figure 21 Axial aberration curve diagram of optical lens in embodiment 4 of the present application.

[0048] Figure 22 Axial aberration curve diagram of optical lens in embodiment 4 of the present application.

[0049] Figure 23 MTF curve graph of the optical lens in Embodiment 4 of the present application.

[0050] Figure 24 Relative luminance curve graph of the optical lens in Embodiment 4 of the present application.

[0051] The following detailed description will further describe the present application with reference to the above-mentioned drawings. DETAILED DESCRIPTION

[0052] For a better understanding of the present application, various aspects of the present application will be described in more detail below with reference to the accompanying drawings. It is to be noted that these detailed descriptions are only descriptions of embodiments of the present application and are not intended in any way to limit the scope of the present application. Throughout the specification, like reference numerals refer to like elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0053] It should be noted that, in the present specification, the expressions first, second, third and the like are used only to distinguish one feature from another feature, and do not indicate any limitation on the features. Thus, the first lens discussed below can also be referred to as the second lens or the third lens without departing from the teachings of the present application.

[0054] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0055] In this context, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the image plane is referred to as the image side surface of the lens.

[0056] It should also be understood that the use of the terms "including", "including having", "having", "containing", and / or "containing having" when used in this specification intends that existence of stated features, elements and / or components but does not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. In addition, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the term "exemplary" is intended to mean an example or an illustration.

[0057] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0058] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0059] The optical lens provided by the embodiments of the present application is composed of eight lenses, which are sequentially arranged along the optical axis from the object side to the imaging surface as 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.

[0060] In some embodiments, the first lens can have a negative focal power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface. The second lens can have a negative focal power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface. The third lens can have a positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface. The fourth lens can have a negative focal power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface. The fifth lens can have a positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface at the near optical axis. The sixth lens can have a negative focal power, the object side surface of which can be a convex surface or a concave surface, and the image side surface of which is a concave surface. The seventh lens can have a positive focal power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface. The eighth lens can have a negative focal power, the object side surface of which is a concave surface, and the image side surface of which can be a convex surface or a concave surface at the near optical axis.

[0061] In some embodiments, the optical lens can further include a stop, which can be located between the third lens and the fourth lens. It can be understood that the stop can be used to limit the amount of light to change the brightness of the imaging.

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

[0063] In some embodiments, the sixth lens and the seventh lens can be cemented to form a cemented lens, which can effectively correct chromatic aberration of the optical lens, reduce the sensitivity of the optical lens to decentration, balance aberration of the optical lens, and improve the imaging quality of the optical lens; and can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens. In some embodiments, the combined focal length f67 of the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 1.7 < f67 / f < 2.6. Satisfying the above range can further correct chromatic aberration of the optical lens and reduce the sensitivity of the optical lens to decentration. Further, 1.84 < f67 / f < 2.39.

[0064] In some embodiments, the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: 0.2 < (R3-R4) / (R3+R4) < 0.8, and the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -1 < (R5-R6) / (R5+R6) < -0.2. Satisfying the above range can correct aberration of the optical lens, ensure smooth light ray trend through the second lens and the third lens, reduce the tolerance sensitivity of the optical lens, and facilitate smooth light ray into the rear end lens. Further, 0.21 < (R3-R4) / (R3+R4) < 0.74, and -1 < (R5-R6) / (R5+R6) < -0.3.

[0065] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.5 < TTL / f < 7.5; and 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: 2.4 < TTL / IH < 3.6. Satisfying the above range helps to balance the total length and volume of the optical lens by reasonably controlling the total length, focal length, and image height of the optical lens, which is conducive to improving the structural stability of the optical lens. Further, 5.91 < TTL / f < 6.95, and 2.6 < TTL / IH < 3.31.

[0066] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 45° < FOV / FNO < 95°; the real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.4 < IH / EPD < 5. Satisfying the above ranges helps to realize the large field of view and large aperture characteristics of the optical lens, which is beneficial to increase the light quantity and improve the relative luminance. Further, 49° < FOV / FNO < 89°, 3.6 < IH / EPD < 4.55.

[0067] In some embodiments, the real image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 1.7 < IH / f < 2.5; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.3 < BFL / f < 1.7. Satisfying the above ranges can reasonably control the image height, focal length and back focal length of the optical lens, and under the condition that the focal length is fixed, the optical lens can improve the characteristics of large target surface and long back focal length. The characteristics of large target surface help to improve the imaging quality of the optical lens, and the characteristics of long back focal length can meet the arrangement requirements of the rear-end chip and reduce the assembly and processing difficulty. Further, 1.84 < IH / f < 2.28, 1.42 < BFL / f < 1.58.

[0068] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.7 < f1 / f < -1.1, the effective focal length f of the optical lens and the object side surface curvature radius R1 of the first lens satisfy: 7 < R1 / f < 88, and the effective focal length f of the optical lens and the image side surface curvature radius R2 of the first lens satisfy: 0.8 < R2 / f < 1.3. Satisfying the above ranges makes the first lens have appropriate negative refractive power and reasonable surface type matching, which helps to collect as much light as possible into the optical lens to obtain more picture information, and can control the trend of edge large-angle light, thereby improving the imaging quality of the optical lens. Further, -1.55 < f1 / f < -1.18, 7.43 < R1 / f < 80.04, 0.9 < R2 / f < 1.15.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -23 < f2 / f < -4.3, the effective focal length f of the optical lens and the object-side surface curvature radius R3 of the second lens satisfy: 6.2 < R3 / f < 21, and the effective focal length f of the optical lens and the image-side surface curvature radius R4 of the second lens satisfy: 2.5 < R4 / f < 4.9. Satisfying the above ranges makes the second lens have a suitable negative focal power and a reasonable surface shape, which helps the divergent light rays enter the rear lenses smoothly and makes the light rays have a smooth trend. Further, -21.31 < f2 / f < -4.7, 6.91 < R3 / f < 19.52, and 2.78 < R4 / f < 4.44.

[0070] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2.9 < f3 / f < 5.3, the effective focal length f of the optical lens and the object-side surface curvature radius R5 of the third lens satisfy: 1.3 < R5 / f < 2.3, and the effective focal length f of the optical lens and the image-side surface curvature radius R6 of the third lens satisfy: 2.6 < R6 / f < 500. Satisfying the above ranges makes the third lens have a suitable positive focal power and a reasonable surface shape, which helps the light rays converge and the lens shape be gentle, thereby reducing the volume and cost.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.7 < f6 / f < -1.2, and the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 0.8 < f7 / f < 1.1. Satisfying the above ranges makes the sixth lens and the seventh lens have a suitable focal length ratio, which helps reasonably control the light deflection and makes the overall structure of the optical lens more compact. Further, -1.62 < f6 / f < -1.3, and 0.9 < f7 / f < 0.96.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -5.7 < f8 / f < -3, and the combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -1.7 < f123 / f45678 < -0.9. By satisfying the above ranges, by reasonably controlling the focal length ratio of the eighth lens and the focal length distribution of the optical lens as a whole, the light ray to the image plane is smoothly controlled, a large target surface characteristic is obtained, and the optical lens is ensured to have high resolving power on the basis of eliminating ghost images, thereby improving the imaging quality of the optical lens. Further, -5.21 < f8 / f < -3.26, and -1.53 < f123 / f45678 < -0.98.

[0073] In some embodiments, the object side surface curvature radius R1 of the first lens and the image side surface curvature radius R2 of the first lens satisfy: 0.7 < (R1-R2) / (R1+R2) < 1, and the object side surface curvature radius R13 of the seventh lens and the image side surface curvature radius R14 of the seventh lens satisfy: -0.5 < (R13+R14) / (R13-R14) < -0.1. By satisfying the above ranges, by reasonably controlling the surface shape of the first lens and the seventh lens, the light ray entering the front end of the optical lens is smoothly controlled, and the light ray entering the eighth lens is smoothly controlled, the difficulty of aberration correction of other lenses in the optical lens is reduced, and the tolerance sensitivity of the optical lens as a whole is reduced. Further, 0.77 < (R1-R2) / (R1+R2) < 0.98, and -0.41 < (R13+R14) / (R13-R14) < -0.19.

[0074] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -6.3 < f4 / f < -2.1, the effective focal length f of the optical lens and the object side surface curvature radius R7 of the fourth lens satisfy: 1.7 < R7 / f < 2.4, and the effective focal length f of the optical lens and the image side surface curvature radius R8 of the fourth lens satisfy: 0.7 < R8 / f < 1.4. By satisfying the above ranges, by reasonably controlling the focal length ratio of the fourth lens and the surface shape matching, the light ray emitted through the front end lens is collected, and the collected light ray smoothly enters the rear lenses, and the resolving power of the optical lens is improved. Further, -5.87 < f4 / f < -2.31, 1.85 < R7 / f < 2.19, and 0.72 < R8 / f < 1.26.

[0075] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1 < f5 / f < 1.4, the effective focal length f of the optical lens and the radius of curvature R9 on the object side of the fifth lens satisfy: 0.8 < R9 / f < 1.3, and the effective focal length f of the optical lens and the radius of curvature R10 on the image side of the fifth lens satisfy: -20 < R10 / f < -9. By satisfying the above ranges, the proportion of the focal length of the fifth lens and the surface type are reasonably controlled, which helps to smooth the light ray trend of the front end lens, corrects the aberration generated by the front end lens, and improves the imaging quality. Further, 1.12 < f5 / f < 1.32, 0.81 < R9 / f < 1.19, and -18.65 < R10 / f < -9.53.

[0076] In some embodiments, the optical lens satisfies the condition: 2.3mm < f < 3.1mm, 1.1mm < EPD < 1.6mm, 13.5mm < TTL < 19mm, 1.8 < FNO < 2.2, 18° < CRA < 24°, 3.3mm < BFL < 4.5mm, 90° < FOV < 190°, and 5mm < IH < 6mm; wherein f represents the effective focal length of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, FNO represents the aperture value of the optical lens, CRA represents the angle of incidence of the chief ray at the maximum image height of the optical lens, BFL represents the back focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, and IH represents the real image height corresponding to the maximum field of view angle of the optical lens. By satisfying the above conditions, it is shown that the optical lens provided by the embodiments of the present application at least has the characteristics of large field of view angle, large aperture, high imaging quality, etc. More specifically, 2.55mm < f < 2.87mm, 1.27mm < EPD < 1.44mm, 15.13mm < TTL < 17.8mm, 1.9 < FNO < 2.1, 19.95° < CRA < 21.79°, 3.64mm < BFL < 4.13mm, 99° < FOV < 177°, and 5.27mm < IH < 5.81mm.

[0077] In some embodiments, the lens material in the optical lens provided by the present application can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. When the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristics of the glass itself. In the optical lens provided by the present application, the first lens, the second lens, the fifth lens, the sixth lens and the seventh lens are glass lenses, and the third lens, the fourth lens and the eighth lens are plastic lenses.

[0078] 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 a spherical lens or an aspherical lens. Compared with a spherical structure, an aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving the miniaturization of the lens. More specifically, the third lens, the fourth lens, the fifth lens and the eighth lens of the present application adopt an aspherical lens, and the first lens, the second lens, the sixth lens and the seventh lens adopt a spherical lens.

[0079] In various embodiments of the present application, when the lens adopts an aspherical lens, the shape of each aspherical surface of the optical lens satisfies the following equation:

[0080] ;

[0081] wherein z is the distance of the curved surface from the vertex of the curved surface in the direction of the optical axis, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the quadratic surface coefficient, and B, C, D, E, F, G and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order and sixteenth-order surface coefficients, respectively.

[0082] The present application will be further described in the following embodiments. In various embodiments, the thickness, the radius of curvature and the material selection of each lens in the optical lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present application, but the embodiments of the present application are not limited to the following embodiments only, and any changes, substitutions, combinations or simplifications made without departing from the innovative points of the present application should be regarded as equivalent replacement modes, and are included in the protection scope of the present application.

[0083] Embodiment 1

[0084] Please refer to Figure 1 , which is a structural schematic diagram of the optical lens 100 provided in the embodiment 1 of the present application. The optical lens sequentially includes a first lens L1, a second lens L2, a third lens L3, a diaphragm ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G1 along the optical axis from the object side to the imaging surface.

[0085] The first lens L1 has a negative focal power, the object side surface S1 thereof is a convex surface, and the image side surface S2 thereof is a concave surface.

[0086] The second lens L2 has a negative focal power, the object side surface S3 thereof is a convex surface, and the image side surface S4 thereof is a concave surface.

[0087] The third lens L3 has a positive focal power, the object side surface S5 thereof is a convex surface, and the image side surface S6 thereof is a concave surface.

[0088] The fourth lens L4 has negative focal power, the object side S7 is convex, and the image side S8 is concave;

[0089] The fifth lens L5 has positive focal power, the object side S9 is convex, and the image side S10 is convex at the near optical axis;

[0090] The sixth lens L6 has negative focal power, the object side S11 is concave, and the image side is concave;

[0091] The seventh lens L7 has positive focal power, the object side is convex, and the image side S13 is convex;

[0092] The sixth lens L6 and the seventh lens L7 form a cemented lens group with positive focal power, that is, the cemented surface S12 of the image side of the sixth lens L6 and the object side of the seventh lens L7;

[0093] The eighth lens L8 has negative focal power, the object side S14 is concave, and the image side S15 is concave at the near optical axis.

[0094] The object side S16 and the image side S17 of the filter G1 are both flat;

[0095] The imaging surface S18 is flat.

[0096] The first lens L1, the second lens L2, the sixth lens L6, and the seventh lens L7 all use glass spherical lenses, the fifth lens L5 uses a glass aspherical lens, and the third lens L3, the fourth lens L4, and the eighth lens L8 all use plastic aspherical lenses.

[0097] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0098] Table 1-1

[0099]

[0100] The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0101] Table 1-2

[0102]

[0103] Figure 2 The F-Tan(Theta) distortion curve of the optical lens 100 in this embodiment is shown, which represents the distortion of different field angles on the imaging surface. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, as the half field angle increases, the change of the distortion value is relatively stable, which indicates that the optical lens 100 can better correct the distortion.

[0104] Figure 3 The axial aberration curve of the optical lens 100 in the embodiment is shown, which represents the axial aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the shift of the axial aberration is controlled within-0.06mm~0.08mm, which shows that the optical lens 100 can better correct the axial aberration.

[0105] Figure 4 The curve of the optical lens 100 in the embodiment is shown, which represents the color difference of each wavelength at different image heights on the imaging surface relative to the central wavelength (0.555μm), the horizontal axis represents the color difference value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the figure, the vertical color difference of the longest wavelength and the shortest wavelength is controlled within-1μm~4μm, which shows that the optical lens 100 can better correct the color difference.

[0106] Figure 5 The modulation transfer function (MTF) curve of the optical lens 100 in the embodiment is shown, which represents the lens imaging modulation degree of different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the embodiment is above 0.4 in the full field of view, and the MTF curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in low and high frequency conditions.

[0107] Figure 6 The relative luminance curve of the optical lens 100 in the embodiment is shown, which represents the relative luminance value of different field angles on the imaging surface, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative luminance (unit: %). As can be seen from the figure, the relative luminance value of the optical lens is still greater than 75% at the maximum half field angle, which shows that the optical lens has good relative luminance.

[0108] Embodiment 2

[0109] Please refer to Figure 7 , which is a structural schematic diagram of the optical lens 200 provided in the embodiment 2 of the present application. Compared with the embodiment 1, the main difference is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0110] The related parameters of each lens in the optical lens 200 in the embodiment 2 are shown in Table 2-1.

[0111] Table 2-1

[0112]

[0113] The surface profile parameters of the aspherical lens of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0114] Table 2-2

[0115]

[0116] In the present embodiment, the F-Tan(Theta) distortion curve, the axial aberration curve, the transverse chromatic aberration curve, the MTF curve, and the relative illumination diagram of the optical lens 200 are respectively shown in Figures 8 to 12 .

[0117] As can be seen from Figure 8 , the change of the distortion value is relatively stable with the increase of the half field angle, which indicates that the optical lens 200 can better correct the distortion.

[0118] As can be seen from Figure 9 , the shift of the axial aberration is controlled within-0.06mm~0.08mm, which indicates that the optical lens 200 can better correct the axial aberration.

[0119] As can be seen from Figure 10 , the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within-1μm~4μm, which indicates that the optical lens 200 can better correct the chromatic aberration.

[0120] As can be seen from Figure 11 , the MTF value of the present embodiment is all above 0.4 within the full field of view, and the MTF curve is uniformly and smoothly decreased from the center to the edge of the field of view, which has better imaging quality and better detail resolution ability in the case of low frequency and high frequency.

[0121] As can be seen from Figure 12 , the relative illumination value of the optical lens is still greater than 75% at the maximum half field angle, which indicates that the optical lens has better relative illumination.

[0122] Embodiment 3

[0123] Please refer to Figure 13 , which is a structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present application, and the main difference between the present embodiment and Embodiment 1 is that the optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.

[0124] The related parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0125] Table 3-1

[0126]

[0127] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0128] Table 3-2

[0129]

[0130] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination diagram of the optical lens 300 are respectively as follows: Figures 14 to 18 As shown.

[0131] from Figure 14 As can be seen, the distortion value changes relatively smoothly as the half field of view increases, indicating that the optical lens 300 can correct distortion well.

[0132] from Figure 15 As can be seen, the axial aberration offset is controlled within -0.04mm to 0.06mm, indicating that the optical lens 300 can correct axial aberration well.

[0133] from Figure 16 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -1μm to 5μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0134] from Figure 17 As can be seen, the MTF value of this embodiment is above 0.35 throughout the entire field of view. The MTF curve decreases smoothly and evenly from the center to the edge of the field of view, demonstrating good imaging quality and good detail resolution in both low and high frequency conditions.

[0135] from Figure 18 As can be seen, the relative illumination value of the optical lens is still greater than 70% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0136] Example 4

[0137] Please see Figure 19 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 object side surface S11 of the sixth lens L6 is convex, the image side surface S15 of the eighth lens L8 is convex, and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0138] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0139] Table 4-1

[0140]

[0141] The surface profile parameters of the aspherical lens of the optical lens 400 in Embodiment 4 are shown in Table 4-2.

[0142] Table 4-2

[0143]

[0144] In this embodiment, the F-Tan(Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination diagram of the optical lens 400 are shown in FIGS. 4-1 to 4-5, respectively. Figures 20 to 24

[0145] As can be seen from FIG. 4-1, the change of the distortion value is relatively stable as the half field angle increases, indicating that the optical lens 400 can better correct the distortion. Figure 20

[0146] As can be seen from FIG. 4-2, the shift of the axial aberration is controlled within -0.1mm~0.06mm, indicating that the optical lens 400 can better correct the axial aberration. Figure 21

[0147] As can be seen from FIG. 4-3, the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2μm~4μm, indicating that the optical lens 400 can better correct the chromatic aberration. Figure 22

[0148] As can be seen from FIG. 4-4, the MTF value of this embodiment is above 0.3 within the full field of view, and the MTF curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in the case of low frequency and high frequency. Figure 23

[0149] As can be seen from FIG. 4-5, the relative illumination value of the optical lens is still greater than 75% at the maximum half field angle, indicating that the optical lens has good relative illumination. Figure 24

[0150] Please refer to Table 5, the optical properties corresponding to each of the above embodiments, including the effective focal length f, the total optical length TTL, the aperture value FNO, the real image height IH corresponding to the maximum field of view, the chief ray angle of incidence CRA at the maximum image height, the maximum field of view FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0151] Table 5

[0152]

[0153] ​​​​​​In summary, the optical lens provided by the present application adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens is improved, the aberration is reduced, and the imaging quality of the optical lens is improved, so that the lens has one or more advantages of large field of view, large aperture, high imaging quality, and the like.

[0154] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0155] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An optical lens consisting of eight pieces of lenses, characterized in that, In order from the object side to the imaging plane along the optical axis, the optical lens comprises in sequence: 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 positive refractive power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; a fourth 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 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 at the near optical axis; a sixth lens with negative refractive power, the image side surface of which is a concave surface; a seventh 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; an eighth lens with negative refractive power, the object side surface of which is a concave surface; wherein the object side surface curvature radius R3 of the second lens and the image side surface curvature radius R4 of the second lens satisfy: 0.2<(R3-R4) / (R3+R4)<0.8, and the object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: -1<(R5-R6) / (R5+R6)<-0.

2.

2. The optical lens of claim 1, wherein, The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.5<TTL / f<7.5; and 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: 2.4<TTL / IH<3.

6.

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: 45°<FOV / FNO<95°; and 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: 3.4<IH / EPD<5.

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: 1.7<IH / f<2.5; and the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.3<BFL / f<1.

7.

5. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.7<f1 / f<-1.1, the effective focal length f of the optical lens and the object side surface curvature radius R1 of the first lens satisfy: 7<R1 / f<88, and the effective focal length f of the optical lens and the image side surface curvature radius R2 of the first lens satisfy: 0.8<R2 / f<1.

3.

6. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -23<f2 / f<-4.3, the effective focal length f of the optical lens and the object side surface curvature radius R3 of the second lens satisfy: 6.2<R3 / f<21, and the effective focal length f of the optical lens and the image side surface curvature radius R4 of the second lens satisfy: 2.5<R4 / f<4.

9.

7. The optical lens of claim 1, wherein, An effective focal length f of the optical lens and a focal length f3 of the third lens satisfy: 2.9 < f3 / f < 5.3, the effective focal length f of the optical lens and a curvature radius R5 of an object side surface of the third lens satisfy: 1.3 < R5 / f < 2.3, and the effective focal length f of the optical lens and a curvature radius R6 of an image side surface of the third lens satisfy: 2.6 < R6 / f < 500.

8. The optical lens of claim 1, wherein, An effective focal length f of the optical lens and a focal length f6 of the sixth lens satisfy: -1.7 < f6 / f < -1.2, and the effective focal length f of the optical lens and a focal length f7 of the seventh lens satisfy: 0.8 < f7 / f < 1.

1.

9. The optical lens of claim 1, wherein, An effective focal length f of the optical lens and a focal length f8 of the eighth lens satisfy: -5.7 < f8 / f < -3, and a combined focal length f123 of the first lens, the second lens and the third lens and a combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -1.7 < f123 / f45678 < -0.

9.

10. The optical lens of claim 1, wherein, A curvature radius R1 of an object side surface of the first lens and a curvature radius R2 of an image side surface of the first lens satisfy: 0.7 < (R1-R2) / (R1+R2) < 1, and a curvature radius R13 of an object side surface of the seventh lens and a curvature radius R14 of an image side surface of the seventh lens satisfy: -0.5 < (R13+R14) / (R13-R14) < -0.1.

Images