Optical lens

Abstract

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

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

[0006] An optical lens is composed of eight lenses, which include, along the optical axis from the object side to the imaging surface:

[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;

[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 convex 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 concave surface, and the image side surface of which is a convex surface;

[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 convex surface near the optical axis, and the image side surface of which is a concave surface near the optical axis;

[0015] The radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 0.3 < (R7-R8) / (R7+R8) < 0.6; the radius of curvature R9 of the object side surface of the fifth lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: 0.8 < (R9-R10) / (R9+R10) < 1.

[0016] Further preferably, the total track length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6 < TTL / f < 7; 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: 2.3 < TTL / IH < 2.9.

[0017] Further preferably, the maximum field angle FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 65° < FOV / FNO < 85°; 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: 4.5 < IH / EPD < 5.5.

[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: 2.2 < IH / f < 2.9; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.6 < BFL / f < 1.

[0019] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2 < f1 / f < -1.2; the effective focal length f of the optical lens and the radius of curvature R1 of the object side surface of the first lens satisfy: 2.7 < R1 / f < 6.5; the effective focal length f of the optical lens and the radius of curvature R2 of the image side surface of the first lens satisfy: 0.8 < R2 / f < 1.2.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -13 < f4 / f < -2; the effective focal length f of the optical lens and the radius of curvature R7 of the object side surface of the fourth lens satisfy: 3 < R7 / f < 9; the effective focal length f of the optical lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 0.9 < R8 / f < 3.9.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.5 < f5 / f < 2.4; the effective focal length f of the optical lens and the radius of curvature R9 of the object side surface of the fifth lens satisfy: -90 < R9 / f < -12; the effective focal length f of the optical lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: -1.4 < R10 / f < -0.9.

[0022] Further preferably, an effective focal length f of the optical lens and a focal length f7 of the seventh lens satisfy: 1 < f7 / f < 1.4; the effective focal length f of the optical lens and a radius of curvature R13 on the object side of the seventh lens satisfy: 0.9 < R13 / f < 1.2; the effective focal length f of the optical lens and a radius of curvature R14 on the image side of the seventh lens satisfy: -4 < R14 / f < -2.

[0023] Further preferably, an effective focal length f of the optical lens and a focal length f8 of the eighth lens satisfy: -11 < f8 / f < -3.5; the effective focal length f of the optical lens and a radius of curvature R15 on the object side of the eighth lens satisfy: 4 < R15 / f < 25.5; the effective focal length f of the optical lens and a radius of curvature R16 on the image side of the eighth lens satisfy: 1.4 < R16 / f < 3.6.

[0024] Further preferably, 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: 0.3 < f123 / f45678 < 1.4; a half radius of light passing d1 on the object side of the first lens and a half radius of light passing d16 on the image side of the eighth lens satisfy: 1.1 < d1 / d16 < 2.3.

[0025] Compared with the prior art, the optical lens provided by the present application adopts eight lenses with specific focal lengths, and through specific surface shape matching and reasonable focal length 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, etc. 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 MTF curve of the optical lens in embodiment 1 of the present application.

[0032] Figure 6 Relative illuminance curve of the optical lens in embodiment 1 of the present application.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0050] Figure 24 Axial aberration curve 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 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 is to 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 the sake 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 the present specification, 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 exclude 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 can be a concave surface or a convex surface, and the image side surface of which can be a concave surface or a convex 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 convex 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 concave surface, and the image side surface of which is a convex surface. The sixth lens can have a negative focal power, the object side surface of which can be a concave surface or a convex 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 convex surface at the near optical axis, and the image side surface of which is a concave surface at the near optical axis.

[0061] In some embodiments, the optical lens can further include a diaphragm, which can be located between the third lens and the fourth lens. It can be understood that the diaphragm 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 together 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. In addition, the cemented lens can 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.

[0064] In some embodiments, the curvature radius R7 of the object side surface of the fourth lens and the curvature radius R8 of the image side surface of the fourth lens satisfy: 0.3<(R7-R8) / (R7+R8)<0.6; and the curvature radius R9 of the object side surface of the fifth lens and the curvature radius R10 of the image side surface of the fifth lens satisfy: 0.8<(R9-R10) / (R9+R10)<1. Satisfying the above ranges can correct the aberration of the optical lens, ensure smooth light ray trend through the fourth and fifth lenses, reduce the tolerance sensitivity of the optical lens, and facilitate smooth light ray entry. More specifically, 0.39<(R7-R8) / (R7+R8)<0.55; and 0.85<(R9-R10) / (R9+R10)<0.98.

[0065] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6<TTL / f<7; 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: 2.3<TTL / IH<2.9. Satisfying the above ranges can help the optical lens achieve a balance between the total length and the volume by reasonably controlling the total length, the focal length, and the image height of the optical lens, and facilitate improving the structural stability of the optical lens. More specifically, 6.5<TTL / f<6.76; and 2.54<TTL / IH<2.66.

[0066] In some embodiments, the maximum field angle FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 65°<FOV / FNO<85°; 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: 4.5<IH / EPD<5.5. Satisfying the above ranges can help achieve the characteristics of large field angle and large aperture of the optical lens, and facilitate increasing the light flux and improving the relative luminance. More specifically, 69.72°<FOV / FNO<80.1°; and 4.91<IH / EPD<5.26.

[0067] In some embodiments, a real image height IH corresponding to a maximum field of view angle of the optical lens satisfies: 2.2 < IH / f < 2.9, and a back focal length BFL of the optical lens satisfies: 0.6 < BFL / f < 1. 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 have the characteristics of large target surface and long back focal length. The characteristic of large target surface helps to improve the imaging quality of the optical lens, and the characteristic of long back focal length can meet the arrangement requirements of the rear-end chip and reduce the assembly and processing difficulty. More specifically, 2.45 < IH / f < 2.64, and 0.67 < BFL / f < 0.91.

[0068] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2 < f1 / f < -1.2, the effective focal length f of the optical lens and the object side surface radius of curvature R1 of the first lens satisfy: 2.7 < R1 / f < 6.5, and the effective focal length f of the optical lens and the image side surface radius of curvature R2 of the first lens satisfy: 0.8 < R2 / f < 1.2. Satisfying the above ranges makes the first lens have a suitable negative refractive power and a reasonable surface shape, which helps to collect as much light as possible into the optical lens to obtain more picture information, and can control the trend of the edge large-angle light to improve the imaging quality of the optical lens. More specifically, -1.89 < f1 / f < -1.38, 2.96 < R1 / f < 5.97, and 0.9 < R2 / f < 1.11.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -13 < f4 / f < -2, the effective focal length f of the optical lens and the object side surface radius of curvature R7 of the fourth lens satisfy: 3 < R7 / f < 9, and the effective focal length f of the optical lens and the image side surface radius of curvature R8 of the fourth lens satisfy: 0.9 < R8 / f < 3.9. Satisfying the above ranges can reasonably control the focal length ratio and surface shape of the fourth lens, which helps to collect light emitted by the front-end lens and smoothly enter the rear lenses, and is conducive to improving the resolving power of the optical lens. More specifically, -11.82 < f4 / f < -2.28, 3.32 < R7 / f < 8.38, and 1.01 < R8 / f < 3.6.

[0070] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.5 < f5 / f < 2.4; the effective focal length f of the optical lens and the radius of curvature R9 on the object side of the fifth lens satisfy: -90 < R9 / f < -12; 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: -1.4 < R10 / f < -0.9. Satisfying the above ranges, by reasonably controlling the focal length proportion and the surface shape of the fifth lens, the light ray trend of the front end lens is gently controlled, the aberration generated by the front end lens is corrected, and the imaging quality is improved. More specifically, 1.63 < f5 / f < 2.19; -85.55 < R9 / f < -13.13; and -1.19 < R10 / f < -1.01.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1 < f7 / f < 1.4; the effective focal length f of the optical lens and the radius of curvature R13 on the object side of the seventh lens satisfy: 0.9 < R13 / f < 1.2; and the effective focal length f of the optical lens and the radius of curvature R14 on the image side of the seventh lens satisfy: -4 < R14 / f < -2. Satisfying the above ranges, by reasonably setting the focal length and the surface shape of the seventh lens, the chromatic aberration of the system can be better corrected in cooperation with the sixth lens, and the overall imaging quality is improved. More specifically, 1.04 < f7 / f < 1.23; 0.95 < R13 / f < 1.1; and -3.62 < R14 / f < -2.19.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -11 < f8 / f < -3.5; the effective focal length f of the optical lens and the radius of curvature R15 on the object side of the eighth lens satisfy: 4 < R15 / f < 25.5; and the effective focal length f of the optical lens and the radius of curvature R16 on the image side of the eighth lens satisfy: 1.4 < R16 / f < 3.6. Satisfying the above ranges, by reasonably controlling the focal length proportion and the surface shape of the eighth lens, the light ray trend to the image plane is controlled to be stable, the characteristics of a large target surface are obtained, and the optical lens is ensured to have a high resolving power on the basis of eliminating ghost images, and the imaging quality of the optical lens is improved. More specifically, -10.74 < f8 / f < -3.79; 4.4 < R15 / f < 23.24; and 1.53 < R16 / f < 3.27.

[0073] In some embodiments, 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: 0.3 < f123 / f45678 < 1.4; the combined focal length f123 of the first lens, the second lens and the third lens and an effective focal length f of the optical lens satisfy: 1.4 < f123 / f < 3.5; the combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 2.4 < f45678 / f < 4.3. Satisfying the above ranges, by reasonably setting the positive refractive power of the front lens group and the rear lens group, the distortion and the astigmatism generated by the front lens and the rear lens of the optical lens are balanced, and the imaging quality of the optical lens is improved. More specifically, 0.38 < f123 / f45678 < 1.26; 1.53 < f123 / f < 3.26; 2.6 < f45678 / f < 3.98.

[0074] In some embodiments, an object side half aperture diameter d1 of the first lens and an image side half aperture diameter d16 of the eighth lens satisfy: 1.1 < d1 / d16 < 2.3. Satisfying the above range, by controlling the aperture ratio of the front lens and the rear lens, the light ray trend is limited within a reasonable range, and the imaging surface illuminance is uniform. More specifically, 1.19 < d1 / d16 < 2.14.

[0075] In some embodiments, an effective focal length f of the optical lens, a maximum field of view FOV of the optical lens and a real image height IH corresponding to the maximum field of view of the optical lens satisfy: 50° < f x FOV / IH < 65°. Satisfying the above range, by reasonably limiting the relationship among the focal length, the field of view and the image height of the optical lens, the balance between the large field of view and the large target surface imaging of the optical lens is achieved. More specifically, 53.3° < f x FOV / IH < 63.47°.

[0076] In some embodiments, an object side half aperture diameter d1 of the first lens, a real image height IH of the optical lens and a maximum field of view FOV of the optical lens satisfy: 0.2 < d1 / (IH / 2) / tan(FOV / 2) < 0.6. Satisfying the above range, the optical lens has a large field of view and a large image surface while the front aperture is small. More specifically, 0.2 < d1 / (IH / 2) / tan(FOV / 2) < 0.56.

[0077] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -50 < f2 / f < -1.5. Satisfying the above range makes the second lens have a proper negative focal length, which helps to make the divergent light rays smoothly enter the lenses in the rear end, and meanwhile makes the light rays trend smoothly. More specifically, -47.61 < f2 / f < -1.62.

[0078] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1 < f3 / f < 2.6. Satisfying the above range makes the third lens have a proper positive focal length, which helps to converge the light rays, and the lens shape is gentle, which is beneficial to reduce the volume and reduce the cost. More specifically, 1.13 < f3 / f < 2.45.

[0079] 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 < -0.8. Satisfying the above range, by reasonably setting the focal length 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 is improved. More specifically, -1.54 < f6 / f < -0.85.

[0080] In some embodiments, the optical lens satisfies the condition: 2.2mm < f < 3mm, 1.2mm < EPD < 1.5mm, 16mm < TTL < 19mm, 1.8 < FNO < 2.2, 14° < CRA < 17°, 1.8mm < BFL < 2.3mm, 130° < FOV < 170°, 6mm < IH < 7mm; 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 chief ray angle of incidence 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. Satisfying the above conditions indicates 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, 2.45mm < f < 2.78mm, 1.22mm < EPD < 1.39mm, 16.43mm < TTL < 18.01mm, 1.9 < FNO < 2.1, 14.4° < CRA < 16.58°, 1.88mm < BFL < 2.23mm, 139.45° < FOV < 160.1°, 6.39mm < IH < 6.81mm.

[0081] 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 due to the low dispersion characteristic 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.

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

[0083] In various embodiments of the present application, when the lens is an aspherical lens, the shape of each aspherical surface of the optical lens satisfies the following equation:

[0084]

[0085] 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.

[0086] 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, and any changes, substitutions, combinations or simplifications made without departing from the innovative points of the present application should be regarded as equivalent replacement methods, and are included in the protection scope of the present application.

[0087] Embodiment 1

[0088] 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 the first lens L1, the second lens L2, the third lens L3, the diaphragm ST, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8 and the filter G1 along the optical axis from the object side to the imaging surface.

[0089] The first lens L1 has negative focal power, the object side S1 is a convex surface, and the image side S2 is a concave surface.

[0090] The second lens L2 has negative focal power, the object side S3 is a convex surface, and the image side S4 is a concave surface.

[0091] The third lens L3 has positive focal power, the object side S5 is a convex surface, and the image side S6 is a convex surface.

[0092] The fourth lens L4 has negative focal power, the object side S7 is a convex surface, and the image side S8 is a concave surface.

[0093] The fifth lens L5 has positive focal power, the object side S9 is a concave surface, and the image side S10 is a convex surface.

[0094] The sixth lens L6 has negative focal power, the object side S11 is a convex surface, and the image side is a concave surface.

[0095] The seventh lens L7 has positive focal power, the object side is a convex surface, and the image side S13 is a convex surface.

[0096] The sixth lens L6 and the seventh lens L7 form a cemented lens group with positive focal power, i.e., the cemented surface of the image side of the sixth lens L6 and the object side of the seventh lens L7 is S13.

[0097] The eighth lens L8 has negative focal power, the object side S14 is a convex surface near the optical axis, and the image side S15 is a concave surface near the optical axis.

[0098] The object side S16 and the image side S17 of the filter G1 are both flat surfaces.

[0099] The imaging surface S18 is a flat surface.

[0100] The first lens L1, the second lens L2, the sixth lens L6, and the seventh lens L7 are all glass spherical lenses, the fifth lens L5 is a glass aspherical lens, and the third lens L3, the fourth lens L4, and the eighth lens L8 are all plastic aspherical lenses.

[0101] The related parameters of the lenses in the optical lens 100 in Example 1 are shown in Table 1-1.

[0102] Table 1-1

[0103]

[0104] The surface type parameters of the aspherical lenses of the optical lens 100 in Example 1 are shown in Table 1-2.

[0105] Table 1-2

[0106] Face number K B C D E F G H S5 8.60E-01 2.09E-03 -3.21E-03 2.07E-03 -7.48E-04 2.97E-04 -1.10E-04 1.16E-05 S6 -1.77E+01 -2.01E-02 1.30E-02 -9.59E-03 5.43E-03 -1.88E-03 2.97E-04 -1.51E-05 S7 -1.03E+02 5.25E-03 -1.05E-02 5.25E-03 -9.58E-04 -4.24E-04 1.39E-04 -2.28E-05 S8 -1.42E+01 -7.92E-03 8.41E-04 -2.65E-04 1.69E-04 8.55E-05 5.47E-06 -1.03E-05 S9 3.85E+02 -2.77E-02 2.19E-03 -1.59E-03 1.70E-06 2.93E-04 0.00E+00 0.00E+00 S10 -2.78E-01 -5.23E-03 -3.09E-04 -3.25E-04 5.24E-05 -8.65E-06 0.00E+00 0.00E+00 S14 -1.58E+02 -1.31E-02 1.01E-03 -9.50E-06 -1.20E-06 -7.05E-07 4.08E-10 7.72E-09 S15 -1.26E+01 -9.74E-03 3.77E-04 2.17E-05 -2.66E-06 -5.97E-07 6.78E-08 -1.27E-09

[0107] Figure 2 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, the change of the distortion value is relatively stable with the increase of the field angle, which shows that the optical lens 100 can correct the distortion well.

[0108] Figure 3 Axial aberration curve of the optical lens 100 in this 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 offset of the axial aberration is controlled within-0.04mm-0.02mm, which shows that the optical lens 100 can correct the axial aberration well.

[0109] Figure 4 Vignetting curve of the optical lens 100 in this 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 vignetting value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. As can be seen from the figure, the vignetting of the longest wavelength and the shortest wavelength is controlled within 0-4μm, which shows that the optical lens 100 can correct the color difference well.

[0110] Figure 5 Modulation transfer function (MTF) curve of the optical lens 100 in this embodiment is shown, which represents the imaging modulation degree of the lens at 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 this embodiment is above 0.35 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, which has good imaging quality and good detail resolution ability in both low and high frequency cases.

[0111] Figure 6 Relative illumination curve of the optical lens 100 in this embodiment is shown, which represents the relative illumination 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 illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 90% at the maximum half field angle, which shows that the optical lens has good relative illumination.

[0112] Embodiment 2

[0113] Please refer to Figure 7, as shown is a structural schematic view of the optical lens 200 provided in the embodiment 2 of the present application, compared with the embodiment 1, the main difference lies in that the object side S3 of the second lens L2 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0114] The related parameters of each lens in the optical lens 200 in the embodiment 2 are shown in Table 2-1.

[0115] Table 2-1

[0116]

[0117]

[0118] The surface type parameters of the aspheric lens of the optical lens 200 in the embodiment 2 are shown in Table 2-2.

[0119] Table 2-2

[0120] Face number K B C D E F G H S5 7.74E-01 -5.07E-05 7.20E-04 8.62E-04 -8.73E-04 3.81E-04 -7.25E-05 6.60E-06 S6 -1.24E+01 -7.91E-03 8.29E-03 -7.14E-03 4.67E-03 -1.93E-03 4.90E-04 -5.63E-05 S7 -6.30E+00 8.46E-03 -1.59E-02 4.11E-03 -3.62E-04 -2.74E-04 1.26E-04 -2.51E-05 S8 -6.31E+00 -5.80E-03 9.00E-04 -3.31E-04 1.22E-05 2.66E-05 2.00E-06 -1.19E-06 S9 1.15E+04 -5.96E-03 1.38E-03 1.36E-04 1.90E-05 -6.93E-07 0.00E+00 0.00E+00 S10 -5.72E-01 -3.43E-03 -4.27E-04 4.98E-05 -2.68E-05 4.78E-06 0.00E+00 0.00E+00 S14 -1.19E+02 -1.90E-02 3.27E-04 2.43E-05 -1.61E-06 -1.04E-06 -6.29E-09 2.00E-09 S15 -9.57E+00 -1.33E-02 1.96E-04 1.54E-05 -2.53E-06 -4.13E-07 7.00E-08 -3.42E-09

[0121] 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 luminance diagram of the optical lens 200 are respectively shown in Figure 8 to Figure 12

[0122] It can be seen from Figure 8 that the change of the distortion value is relatively stable with the increase of the field angle, which indicates that the optical lens 200 can correct the distortion well.

[0123] It can be seen from Figure 9 that the shift amount of the axial aberration is controlled within-0.02mm-0.02mm, which indicates that the optical lens 200 can correct the axial aberration well.

[0124] It can be seen from Figure 10 that the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within-1um-4um, which indicates that the optical lens 200 can correct the chromatic aberration well.

[0125] It can be seen from Figure 11 that the MTF value of the present embodiment is above 0.48 in 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 good imaging quality and good detail resolution ability in the low frequency and high frequency cases.

[0126] It can be seen from Figure 12 that the relative luminance value of the optical lens is still greater than 70% at the maximum half field angle, which indicates that the optical lens 200 has good relative luminance.

[0127] ​Embodiment 3

[0128] Please refer to Figure 13 , which is a structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present application. Compared with Embodiment 1, the main difference is that the object side S3 of the second lens L2 is a concave surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0129] The related parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0130] Table 3-1

[0131]

[0132] The surface type parameters of the aspherical lens of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0133] Table 3-2

[0134]

[0135]

[0136] In this embodiment, the F-Tan(Theta) distortion curve, the axial aberration curve, the transverse chromatic aberration curve, the MTF curve, and the relative luminance diagram of the optical lens 300 are shown in Figure 14 to Figure 18 , respectively.

[0137] As can be seen from Figure 14 , the change of the distortion value is relatively stable with the increase of the field angle, which indicates that the optical lens 300 can correct the distortion well.

[0138] As can be seen from Figure 15 , the shift amount of the axial aberration is controlled within-0.2mm-0.05mm, which indicates that the optical lens 300 can correct the axial aberration well.

[0139] As can be seen from Figure 16 , the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within-1μm-3μm, which indicates that the optical lens 300 can correct the chromatic aberration well.

[0140] As can be seen from Figure 17 , the MTF value of this embodiment is above 0.38 in 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 good imaging quality and good detail resolution ability in the low frequency and high frequency cases.

[0141] As can be seen from Figure 18It can be seen from the figure that the relative illumination value of the optical lens is still greater than 70% at the maximum half field angle, which indicates that the optical lens has a good relative illumination.

[0142] Embodiment 4

[0143] Referring to Figure 19 , a structure diagram of an optical lens 400 provided in Embodiment 4 of the present application is shown. Compared with Embodiment 1, the main difference is that the sixth lens L6 and the seventh lens L7 form a cemented lens group with negative focal power; the object side S3 of the second lens L2 is a concave surface; the image side S4 of the second lens L2 is a convex surface; the object side S11 of the sixth lens L6 is a concave surface; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0144] The related parameters of each lens in the optical lens 400 in Embodiment 4 are shown in Table 4-1.

[0145] Table 4-1

[0146]

[0147]

[0148] The surface type parameters of the aspherical lens of the optical lens 400 in Embodiment 4 are shown in Table 4-2.

[0149] Table 4-2

[0150] Face number K B C D E F G H S5 -4.11E+00 4.05E-03 -2.15E-03 2.67E-03 -1.34E-03 4.84E-04 -6.91E-05 3.96E-06 S6 1.10E+02 1.21E-02 -1.75E-02 1.66E-02 -2.43E-03 -4.36E-03 2.68E-03 -4.59E-04 S7 -9.32E+02 -7.44E-03 -1.04E-02 5.56E-03 -1.17E-03 -2.92E-04 1.43E-04 -4.57E-05 S8 -2.11E+01 -3.34E-02 -4.38E-03 -5.60E-05 -1.28E-05 5.77E-05 -1.14E-05 -2.46E-06 S9 8.61E+02 -2.88E-02 -4.18E-03 -1.35E-03 2.16E-04 1.96E-04 0.00E+00 0.00E+00 S10 -2.62E-03 -8.09E-03 -9.57E-04 -4.03E-04 6.72E-05 1.42E-05 0.00E+00 0.00E+00 S14 4.07E+01 -1.00E-02 9.07E-06 -5.75E-05 2.77E-05 -7.80E-06 9.22E-07 -4.21E-08 S15 2.09E+00 -1.07E-02 -7.18E-07 1.07E-05 -6.26E-07 -1.86E-07 2.44E-08 -8.98E-10

[0151] In this 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 400 are shown in Figure 20 to Figure 24 , respectively.

[0152] It can be seen from Figure 20 that the change of the distortion value is relatively stable with the increase of the field angle, which indicates that the optical lens 400 can correct the distortion well.

[0153] It can be seen from Figure 21 that the shift amount of the axial aberration is controlled within-0.04mm-0.04mm, which indicates that the optical lens 400 can correct the axial aberration well.

[0154] It can be seen from Figure 22 that the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within-1μm-3μm, which indicates that the optical lens 400 can correct the chromatic aberration well.

[0155] It can be seen from Figure 23It can be seen from the above that the MTF value of the optical lens of the embodiment is greater than 0.4 in 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, and the optical lens has good imaging quality and good detail resolution capability in the case of low frequency and high frequency.

[0156] From Figure 24 It can be seen from the above that the relative illumination value of the optical lens is still greater than 80% at the maximum half field of view, which indicates that the optical lens has good relative illumination.

[0157] Referring to Table 5, the optical properties corresponding to the above embodiments are shown, 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 of the optical lens, and the numerical value corresponding to each conditional expression in each embodiment.

[0158] Table 5

[0159]

[0160]

[0161] 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 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 such as large field of view, large aperture, high imaging quality, etc.

[0162] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction 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.

[0163] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the present patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. An optical lens, comprising eight lenses, characterized in that, It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with negative optical power, whose object side is convex and whose image side is concave; A second lens with negative optical power; A third lens with positive optical power, whose object side is convex and whose image side is convex; A fourth lens with negative optical power, whose object side is convex and whose image side is concave; A fifth lens with positive optical power, whose object side is concave and whose image side is convex; A sixth lens with negative optical power, whose image side is concave; A seventh lens with positive optical power, whose object side is convex and whose image side is convex; An eighth lens with negative optical power, whose object side is convex near the optical axis and whose image side is concave near the optical axis; Wherein, the curvature radius R7 of the object side of the fourth lens and the curvature radius R8 of the image side of the fourth lens satisfy: 0.3 < (R7 - R8) / (R7 + R8) < 0.6; the curvature radius R9 of the object side of the fifth lens and the curvature radius R10 of the image side of the fifth lens satisfy: 0.8 < (R9 - R10) / (R9 + R10) < 1.

2. The optical lens according to claim 1, characterized in that, The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6 < TTL / f < 7; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 2.3 < TTL / IH < 2.

9.

3. The optical lens according to claim 1, characterized in that, The maximum field angle FOV of the optical lens and the f-number FNO of the optical lens satisfy: 65° < FOV / FNO < 85°; 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: 4.5 < IH / EPD < 5.

5.

4. The optical lens according to claim 1, characterized in that, The true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 2.2 < IH / f < 2.9; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.6 < BFL / f < 1.

5. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2 < f1 / f < -1.2; the effective focal length f of the optical lens and the curvature radius R1 of the object side of the first lens satisfy: 2.7 < R1 / f < 6.5; the effective focal length f of the optical lens and the curvature radius R2 of the image side of the first lens satisfy: 0.8 < R2 / f < 1.

2.

6. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -13 < f4 / f < -2; the effective focal length f of the optical lens and the curvature radius R7 of the object side of the fourth lens satisfy: 3 < R7 / f < 9; the effective focal length f of the optical lens and the curvature radius R8 of the image side of the fourth lens satisfy: 0.9 < R8 / f < 3.

9.

7. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.5 < f5 / f < 2.4; the effective focal length f of the optical lens and the object-side curvature radius R9 of the fifth lens satisfy: -90 < R9 / f < -12; the effective focal length f of the optical lens and the image-side curvature radius R10 of the fifth lens satisfy: -1.4 < R10 / f < -0.

9.

8. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1 < f7 / f < 1.4; the effective focal length f of the optical lens and the object-side curvature radius R13 of the seventh lens satisfy: 0.9 < R13 / f < 1.2; the effective focal length f of the optical lens and the image-side curvature radius R14 of the seventh lens satisfy: -4 < R14 / f < -2.

9. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -11 < f8 / f < -3.5; the effective focal length f of the optical lens and the object-side curvature radius R15 of the eighth lens satisfy: 4 < R15 / f < 25.5; the effective focal length f of the optical lens and the image-side curvature radius R16 of the eighth lens satisfy: 1.4 < R16 / f < 3.

6.

10. The optical lens according to claim 1, characterized in that, The combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 0.3 < f123 / f45678 < 1.4; the object-side clear aperture semi-diameter d1 of the first lens and the image-side clear aperture semi-diameter d16 of the eighth lens satisfy: 1.1 < d1 / d16 < 2.3.

Images