Optical lens

Abstract

The application provides an optical lens, which comprises eight lenses in sequence along an optical axis from an object side to an imaging surface, and the eight lenses comprise: a first lens with positive refractive power, the object side of the first lens is a convex surface, and the image side of the first lens is a concave surface; a second lens with positive refractive power, the image side of the second lens is a convex surface; a third lens with negative refractive power, the object side of the third lens is a convex surface near the optical axis, and the image side of the third lens is a concave surface; a fourth lens with refractive power, the object side of the fourth lens is a convex surface; a fifth lens with positive refractive power; a sixth lens with positive refractive power, the image side of the sixth lens is a convex surface; a seventh lens with positive refractive power, the image side of the seventh lens is a convex surface; and an eighth lens with negative refractive power, the object side of the eighth lens is a concave surface, and the image side of the eighth lens is a concave surface near the optical axis. The optical lens provided by the application can improve the imaging quality of the optical lens, reduce aberration, and improve the imaging quality of the optical lens.

Description

TECHNICAL FIELD

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

[0002] With the development of security technology in recent years, the target size requirement of monitoring lenses is getting larger and larger. It is well known that the larger the sensor target size is, the better the photosensitive performance is, and the better the imaging effect is. However, most of the large target lenses on the market currently have the problems of large distortion and poor imaging effect in a relatively dark environment. SUMMARY

[0003] In view of the above problems, the present application aims to provide an optical lens with the advantages of excellent imaging quality.

[0004] The technical scheme adopted by the present application is as follows:

[0005] An optical lens, which comprises eight lenses in total, and sequentially comprises, along the optical axis from the object side to the imaging surface:

[0006] a first 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;

[0007] a second lens with positive refractive power, the image side surface of which is a convex surface;

[0008] a third lens with negative refractive 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;

[0009] a fourth lens with refractive power, the object side surface of which is a convex surface;

[0010] a fifth lens with positive refractive power;

[0011] a sixth lens with positive refractive power, the image side surface of which is a convex surface;

[0012] a seventh lens with positive refractive power, the image side surface of which is a convex surface;

[0013] an eighth lens with negative refractive power, the object side surface of which is a concave surface, and the image side surface of which is a concave surface near the optical axis;

[0014] wherein the real image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 9.5mm<IH / Fno<11mm.

[0015] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.2<f1 / f<1.8; and the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.5<f1 / f2<1.

[0016] It is further preferred that the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.3 < f2 / f < 2.5; the image-side surface curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: -1.5 < R4 / f < -0.6.

[0017] It is further preferred that the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.8 < f3 / f < -1; the object-side surface curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: 2.8 < R5 / f < 4.5.

[0018] It is further preferred that the object-side surface curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.2 < R7 / f < 2; the image-side surface curvature radius R4 of the second lens and the object-side surface curvature radius R5 of the third lens satisfy: -0.35 < R4 / R5 < -0.2.

[0019] It is further preferred that the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.2 < f5 / f < 8.

[0020] It is further preferred that the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 2.2 < f6 / f < 3.5; the image-side surface curvature radius R12 of the sixth lens and the effective focal length f of the optical lens satisfy: -3.5 < R12 / f < -1.3.

[0021] It is further preferred that the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.2 < f7 / f < 2; the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -0.6 < f8 / f < -0.35.

[0022] It is further preferred that the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 1.1 < f1234 / f < 1.8.

[0023] It is further preferred that the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -4 < f7 / f8 < -3; the center thickness CT7 of the seventh lens and the center thickness CT8 of the eighth lens satisfy: 0.33 < CT7 / CT8 < 0.8.

[0024] 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 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 a large image surface, a large aperture, small distortion, high definition and the like. BRIEF DESCRIPTION OF DRAWINGS

[0025] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

[0026] Figure 1 It is a structural schematic diagram of the optical lens in embodiment 1 of the application.

[0027] Figure 2 It is an astigmatism curve diagram of the optical lens in embodiment 1 of the application.

[0028] Figure 3 It is an F-Tan(Theta) distortion curve diagram of the optical lens in embodiment 1 of the application.

[0029] Figure 4 It is an axial aberration curve diagram of the optical lens in embodiment 1 of the application.

[0030] Figure 5 It is a curve diagram of the optical lens in embodiment 1 of the application. Axial chromatic aberration.

[0031] Figure 6 It is a structural schematic diagram of the optical lens in embodiment 2 of the application.

[0032] Figure 7 It is an astigmatism curve diagram of the optical lens in embodiment 2 of the application.

[0033] Figure 8 It is an F-Tan(Theta) distortion curve diagram of the optical lens in embodiment 2 of the application.

[0034] Figure 9 It is an axial aberration curve diagram of the optical lens in embodiment 2 of the application.

[0035] Figure 10 It is a curve diagram of the optical lens in embodiment 2 of the application. Axial chromatic aberration.

[0036] Figure 11 It is a structural schematic diagram of the optical lens in embodiment 3 of the application.

[0037] Figure 12 It is an astigmatism curve diagram of the optical lens in embodiment 3 of the application.

[0038] Figure 13F-Tan (Theta) distortion curve graph of the optical lens in Embodiment 3 of the present application.

[0039] Figure 14 Axial aberration curve graph of the optical lens in Embodiment 3 of the present application.

[0040] Figure 15 Vignetting curve graph of the optical lens in Embodiment 3 of the present application.

[0041] The following detailed description will further describe the present application with reference to the above-mentioned drawings. DETAILED DESCRIPTION

[0042] 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.

[0043] It should be noted that the expressions first, second, third, etc. in the present specification are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, 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.

[0044] 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 surface or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical surface or aspherical surface is not limited to the shape of the spherical surface or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn strictly to scale.

[0045] 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.

[0046] It should also be understood that the use of the terms "have", "has", "having", "include", "includes" or "including" when used in this specification, specifies the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. In addition, when referring to a list of items, the use of "at least one of" indicates that an item falling within any one or more of the listed items is contemplated. Furthermore, the use of "may" when describing embodiments of the present application indicates that one or more embodiments of the present application are contemplated, and the use of "example" is intended to indicate an example or an illustration rather than a preference or requirement. It should also be understood that the use of the terms "about" and "substantially" when used in this specification, indicate that the value of a numerical parameter is within a range of acceptable values that one of ordinary skill in the art would consider to be the value of the numerical parameter ±10% or ±5% of the stated value.

[0047] 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.

[0048] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other, if there is no conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0049] The optical lens provided by the embodiments of the present application comprises 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.

[0050] In some embodiments, the first 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 second lens can have a positive 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 convex surface. The third lens can have a 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. The fourth lens can have a positive focal power or a negative focal power, the object side surface of which is a convex surface, and the image side surface of which can be a concave surface or a convex surface. The fifth lens can have a positive 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 sixth lens can have a positive 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 convex surface. The seventh lens can have a positive 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 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 is a concave surface near the optical axis.

[0051] In some embodiments, the optical lens can further comprise a diaphragm, which can be located between the object side and the first lens. It can be understood that the diaphragm is used to limit the amount of light entering, so as to change the brightness of the imaging.

[0052] 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.

[0053] In some embodiments, the real image height IH corresponding to the maximum field of view angle of the optical lens and the aperture value Fno of the optical lens satisfy: 9.5mm<IH / Fno<11mm. Satisfying the above condition can make the lens have a larger aperture while having a larger imaging target surface, ensuring that the lens has a larger light flux in a darker environment, thereby improving the picture quality of the lens in different environments.

[0054] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.2<f1 / f<1.8. Satisfying the above condition can make the first lens have a larger positive refractive power, improve the edge field of view light collection capability, and facilitate the realization of large wide-angle imaging of the lens.

[0055] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.5<f1 / f2<1. Satisfying the above condition, the first and second lenses both provide positive refractive power, and by reasonably matching the spacing relationship of the first and second lenses, the light can be further converged by mutual cooperation, which is conducive to the further convergence of incident light and better realizes the balance of large wide-angle and large aperture of the lens.

[0056] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.3<f2 / f<2.5; and the image side surface curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: -1.5<R4 / f<-0.6. Satisfying the above conditions can make the second lens have appropriate positive refractive power, which is conducive to smooth transition of light path, improves the imaging quality of the optical lens, and at the same time can reduce the system sensitivity and improve the manufacturing yield.

[0057] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.8<f3 / f<-1; and the object side surface curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: 2.8<R5 / f<4.5. Satisfying the above conditions can make the third lens have a larger negative refractive power, which can greatly diverge the incident light, thereby effectively improving the height of the light entering the imaging surface and better realizing large target surface imaging of the lens.

[0058] In some embodiments, the object-side surface radius of curvature R7 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.2 < R7 / f < 2. By satisfying the above condition, the incident light rays can be smoothly transitioned by reasonably setting the object-side surface radius of curvature of the fourth lens, the difficulty of correcting the edge field distortion is reduced, and the overall imaging quality is improved.

[0059] In some embodiments, the image-side surface radius of curvature R4 of the second lens and the object-side surface radius of curvature R5 of the third lens satisfy: -0.35 < R4 / R5 < -0.2. By satisfying the above condition, the light rays passing through the second lens are properly diverged by reasonably setting the radii of curvature of the adjacent surfaces of the second and third lenses, the light ray trend is smoothly transitioned, and the imaging quality of the optical lens is improved.

[0060] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.2 < f5 / f < 8. By satisfying the above condition, the light rays of the central field are diverged to a certain extent, and the exit angle of the light rays of the edge field is reduced by the curvature of the edge field, and the relative luminance of the edge field is improved.

[0061] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 2.2 < f6 / f < 3.5. By satisfying the above condition, the field curvature and distortion of the optical lens are corrected, and the imaging quality of the optical lens is improved.

[0062] In some embodiments, the image-side surface radius of curvature R12 of the sixth lens and the effective focal length f of the optical lens satisfy: -3.5 < R12 / f < -1.3. By satisfying the above condition, the light rays are better converged, the distance of the light rays reaching the next lens is shortened, and the total length of the optical lens is reduced.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.2 < f7 / f < 2. By satisfying the above condition, the astigmatism and the field curvature of the optical lens are balanced, and the imaging quality of the optical lens is improved.

[0064] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -0.6 < f8 / f < -0.35. By satisfying the above condition, the incident light rays are further diverged, the peripheral light rays and the central light rays are turned up to a higher imaging position, the large target surface imaging of the lens is better achieved, and the imaging quality is improved.

[0065] In some embodiments, the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 1.1 < f1234 / f < 1.8. Satisfying the above condition is conducive to the convergence of light rays, smoothly enters the rear optical system for the light rays entering the front end of the system, makes the overall light path more gentle, and optimizes the aberration to improve the resolution.

[0066] In some embodiments, the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -4 < f7 / f8 < -3; the central thickness CT7 of the seventh lens and the central thickness CT8 of the eighth lens satisfy: 0.33 < CT7 / CT8 < 0.8. Satisfying the above condition, by reasonably setting the focal length and central thickness relationship of the seventh and eighth lenses, the lens has good machinability while being conducive to a certain degree of divergence of the light rays in the central field of view, and the edge field of view of the eighth lens is combined to reduce the exit angle of the edge field of view light, improve the relative luminance of the edge field of view.

[0067] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.1 < BFL / f < 0.15; the back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0.08 < BFL / TTL < 0.12. Satisfying the above condition can make the lens have a suitable back focal length, ensure the compatibility of the lens and the body while making the structure of the lens more compact.

[0068] In some embodiments, 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: 0.62 < TTL / IH < 0.7. Satisfying the above condition can better realize the miniaturization of the lens while ensuring that the lens has a larger image surface and can match a larger size imaging chip to realize high-definition imaging.

[0069] In some embodiments, the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -0.7 < f1234 / f5678 < 0.01. Satisfying the above condition, by reasonably setting the focal length relationship of the front and rear lens groups, it is helpful for the smooth transition of light rays, expands the field angle of the optical imaging lens, reduces the difficulty of correcting distortion and chromatic aberration of the rear lens, and improves the image quality of the optical lens.

[0070] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis and the total optical length TTL of the optical lens satisfy: 0.55 < ∑CT / TTL < 0.65. Satisfying the above condition can effectively compress the total length of the optical lens, and is conducive to the structural design and production process of the optical lens.

[0071] In some embodiments, the optical lens satisfies the condition formula: 8mm < f < 9mm, 80° < FOV < 90°, 10.5mm < TTL < 11.5mm, 1.5 < Fno < 1.7, 15.5mm < IH < 17.5mm; wherein f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value 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 condition indicates that the lens has a large field of view angle, can realize a wide range of shooting range, has a large aperture value, can realize high-definition imaging even in a dark environment, has a large target surface, can match an imaging chip with a large target surface to realize high-definition imaging, and the increase of the target surface can make the pixel distribution more sparse, effectively reduce noise points in a dark environment, have a wider dynamic range, and retain more imaging details in the dark part, thereby presenting a clearer shooting effect.

[0072] 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. The optical lens provided by the present application can adopt a full-plastic lens structure, which not only has excellent imaging performance, but also has a compact structure, and can better realize the balance between miniaturization and high image quality of the lens.

[0073] 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 realizing the miniaturization of the lens. More specifically, 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 all adopt an aspherical lens, which can effectively reduce the aberration of the optical lens, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens.

[0074] In various embodiments of the present application, when the lens adopts an aspherical lens, the surface shape of the aspherical lens satisfies the following equation:

[0075] ;

[0076] wherein z is the distance of the curved surface to 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, A 2iAspherical surface type coefficient of the 2i-th order.

[0077] The application will be further described in the following embodiments. In each embodiment, 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 the preferred embodiments of the application, but the embodiments of the application are not limited to the following embodiments only, any changes, substitutions, combinations or simplifications made without departing from the innovative points of the application should be regarded as equivalent replacement modes, and are included in the protection scope of the application.

[0078] Embodiment 1

[0079] Please refer to Figure 1 , which is a structural schematic diagram of the optical lens 100 provided in the embodiment 1 of the application. The optical lens includes, along the optical axis from the object side to the imaging surface S19, a diaphragm ST, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G1.

[0080] The first lens L1 has positive refractive power, the object side S1 is a convex surface, and the image side S2 is a concave surface;

[0081] The second lens L2 has positive refractive power, the object side S3 is a convex surface, and the image side S4 is a convex surface;

[0082] The third lens L3 has negative refractive power, the object side S5 is a convex surface at the near optical axis, and the image side S6 is a concave surface;

[0083] The fourth lens L4 has positive refractive power, the object side S7 is a convex surface, and the image side S8 is a concave surface;

[0084] The fifth lens L5 has positive refractive power, the object side S9 is a convex surface, and the image side S10 is a concave surface at the near optical axis;

[0085] The sixth lens L6 has positive refractive power, the object side S11 is a convex surface at the near optical axis, and the image side S12 is a convex surface;

[0086] The seventh lens L7 has positive refractive power, the object side S13 is a concave surface, and the image side S14 is a convex surface;

[0087] The eighth lens L8 has negative refractive power, the object side S15 is a concave surface, and the image side S16 is a concave surface at the near optical axis;

[0088] The object side S17 and the image side S18 of the filter G1 are both flat surfaces;

[0089] The imaging surface S19 is a flat surface.

[0090] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are plastic aspherical lenses.

[0091] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0092] Table 1-1

[0093]

[0094] The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0095] Table 1-2

[0096]

[0097] In this embodiment, the astigmatism curve, the F-Tan(Theta) distortion curve, the axial aberration curve, and the lateral chromatic aberration curve of the optical lens 100 are shown in FIGS. 1-1, 1-2, 1-3, and 1-4, respectively. Figure 2 、 Figure 3 、 Figure 4 、 Figure 5

[0098] Figure 2 FIG. 1-1 shows the astigmatism curve of the optical lens 100 in this embodiment, which represents the astigmatism of the light rays on the meridional image surface and the sagittal image surface, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the astigmatism of the meridional image surface and the sagittal image surface is controlled within ±0.15 mm, which shows that the optical lens 100 can correct the astigmatism well.

[0099] Figure 3 FIG. 1-2 shows the F-Tan(Theta) distortion curve of the optical lens 100 in this embodiment, 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 distortion value is controlled within ±2.5%, which shows that the optical lens 100 can correct the distortion well.

[0100] Figure 4 FIG. 1-3 shows the axial aberration curve of the optical lens 100 in this embodiment, 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 ±0.1 mm, which shows that the optical lens 100 can correct the axial aberration well.

[0101] ​Figure 5 A curve graph of the transverse chromatic aberration of the optical lens 100 in the embodiment is shown, which represents the chromatic aberration of each wavelength at different image heights on the imaging surface relative to the central wavelength (0.555 μm), the horizontal axis represents the transverse chromatic aberration 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 graph, the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, which indicates that the optical lens 100 can better correct chromatic aberration.

[0102] Embodiment 2

[0103] Referring to Figure 6 , a structure schematic diagram of the optical lens 200 provided in the embodiment 2 of the present application is shown, and the main difference between the embodiment and the embodiment 1 is that: the object side S3 of the second lens L2 is concave at the near optical axis; the image side S8 of the fourth lens L4 is convex; the object side S9 of the fifth lens L5 is concave; the image side S10 of the fifth lens L5 is convex; the object side S11 of the sixth lens L6 is concave; the object side S13 of the seventh lens L7 is convex at the near optical axis; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0104] The related parameters of each lens in the optical lens 200 in the embodiment 2 are shown in Table 2-1.

[0105] Table 2-1

[0106]

[0107] The surface type parameters of the aspheric lens of the optical lens 200 in the embodiment 2 are shown in Table 2-2.

[0108] Table 2-2

[0109]

[0110] In the embodiment, the astigmatism curve graph, the F-Tan(Theta) distortion curve graph, the axial aberration curve graph, and the transverse chromatic aberration curve graph of the optical lens 200 are shown in Figure 7 , Figure 8 , Figure 9 , Figure 10 respectively.

[0111] As can be seen from Figure 7 , the astigmatism of the meridional image surface and the sagittal image surface is controlled within ±0.15 mm, which indicates that the optical lens 200 can better correct astigmatism.

[0112] As can be seen from Figure 8 , the distortion value is controlled within ±3%, which indicates that the optical lens 200 can better correct distortion.

[0113] It can be seen from Figure 9 that the axial aberration offset is controlled within ±0.1mm, which indicates that the optical lens 200 can better correct the axial aberration.

[0114] It can be seen from Figure 10 that the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2μm, which indicates that the optical lens 200 can better correct the chromatic aberration.

[0115] Embodiment 3

[0116] Please refer to Figure 11 , which is a structural schematic diagram of the optical lens 300 provided in the embodiment 3 of the present application. Compared with the embodiment 1, the main difference is that the fourth lens L4 has a negative focal power; the object side S3 of the second lens L2 is concave at the near optical axis; the object side S11 of the sixth lens L6 is concave; and the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0117] The related parameters of each lens in the optical lens 300 in the embodiment 3 are shown in Table 3-1.

[0118] Table 3-1

[0119]

[0120] The surface type parameters of the aspheric lens of the optical lens 300 in the embodiment 3 are shown in Table 3-2.

[0121] Table 3-2

[0122]

[0123] In this embodiment, the astigmatism curve, the F-Tan(Theta) distortion curve, the axial aberration curve and the transverse chromatic aberration curve of the optical lens 300 are shown in Figure 12 , Figure 13 , Figure 14 , Figure 15 respectively.

[0124] It can be seen from Figure 12 that the astigmatism of the meridional image surface and the sagittal image surface is controlled within ±0.1mm, which indicates that the optical lens 300 can better correct the astigmatism.

[0125] It can be seen from Figure 13 that the distortion value is controlled within ±2.5%, which indicates that the optical lens 300 can better correct the distortion.

[0126] It can be seen from Figure 14 that the axial aberration offset is controlled within ±0.1mm, which indicates that the optical lens 300 can better correct the axial aberration.

[0127] As can be seen from Figure 15 The maximum and minimum axial chromatic aberrations are controlled within ±2 μm, which indicates that the optical lens 300 can correct chromatic aberration well.

[0128] Table 4 shows the optical characteristics of the above-mentioned embodiments, including the effective focal length f, the total track 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.

[0129] Table 4

[0130]

[0131] In summary, the optical lens provided by the present application has at least the following advantages:

[0132] (1) By means of specific surface shape setting and reasonable power distribution, a large field of view is achieved, and a large range of shooting range can be realized; at the same time, a large aperture value is achieved, and high-definition imaging can be realized even in a dark environment.

[0133] (2) The lens has a large target surface, which can match a large target imaging chip to realize high-definition imaging, and the increase of the target surface can make the pixel distribution more sparse, effectively reduce the noise points in a dark environment, and have a wider dynamic range, so that more imaging details can be retained in the dark part, thereby presenting a clearer shooting effect; at the same time, the overall aberration of the optical lens can be corrected reasonably, so that the optical lens has small distortion and high definition, and the imaging quality of the optical lens is improved.

[0134] 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 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.

[0135] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the present application. 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 all within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. An optical lens, eight pieces of lenses in total, characterized in that, It successively includes from the object side to the imaging plane along the optical axis: A first lens with positive optical power, whose object side is convex and whose image side is concave; A second lens with positive optical power, whose image side is convex; A third lens with negative optical power, whose object side is convex near the optical axis and whose image side is concave; A fourth lens with optical power, whose object side is convex; A fifth lens with positive optical power; A sixth lens with positive optical power, whose image side is convex; A seventh lens with positive optical power, whose image side is convex; An eighth lens with negative optical power, whose object side is concave and whose image side is concave near the optical axis; Wherein, the true image height IH corresponding to the maximum field angle of the optical lens and the F - number Fno of the optical lens satisfy: 9.5mm < IH / Fno < 11mm; The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.2 < f1 / f < 1.8; The focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.5 < f1 / f2 < 1; The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: - 1.8 < f3 / f < - 1.

2. The optical lens of claim 1, wherein, The overall length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.62 < TTL / IH < 0.

7.

3. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.3 < f2 / f < 2.5; The radius of curvature R4 of the image side of the second lens and the effective focal length f of the optical lens satisfy: - 1.5 < R4 / f < - 0.

6.

4. The optical lens according to claim 1, characterized in that, The radius of curvature R5 of the object side of the third lens and the effective focal length f of the optical lens satisfy: 2.8 < R5 / f < 4.

5.

5. The optical lens according to claim 1, characterized in that, The radius of curvature R7 of the object side of the fourth lens and the effective focal length f of the optical lens satisfy: 1.2 < R7 / f < 2; The radius of curvature R4 of the image side of the second lens and the radius of curvature R5 of the object side of the third lens satisfy: - 0.35 < R4 / R5 < - 0.

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 f5 of the fifth lens satisfy: 1.2 < f5 / f < 8.

7. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 2.2 < f6 / f < 3.5; The radius of curvature R12 of the image side of the sixth lens and the effective focal length f of the optical lens satisfy: - 3.5 < R12 / f < - 1.

3.

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: 1.2 < f7 / f < 2; The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: - 0.6 < f8 / f < - 0.

35.

9. The optical lens according to claim 1, characterized in that, The combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 1.1 < f1234 / f < 1.

8.

10. The optical lens according to claim 1, characterized in that, The focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -4 < f7 / f8 < -3; the central thickness CT7 of the seventh lens and the central thickness CT8 of the eighth lens satisfy: 0.33 < CT7 / CT8 < 0.8.

Images