Optical lens

Abstract

The application provides an optical lens, which comprises three lenses in sequence along an optical axis from an object side to an imaging surface, and the three lenses comprise: a first lens with negative optical power, wherein an object side surface of the first lens is a concave surface, and an image side surface of the first lens is a concave surface; a second lens with positive optical power, wherein an object side surface of the second lens is a convex surface, and an image side surface of the second lens is a convex surface; and a third lens with positive optical power, wherein an object side surface of the third lens is a convex surface, and an image side surface of the third lens is a concave surface; wherein a real image height IH corresponding to a maximum field angle of the optical lens and an effective focal length f of the optical lens satisfy: 0.9<IH / f<1.35. The optical lens provided by the application has one or more advantages such as long focal length, large aperture, large refractive index of lens material, etc.

Description

TECHNICAL FIELD

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

[0002] Traditional vehicle-mounted vision relies on visible light cameras, and the performance of the visible light cameras decreases sharply in low-visibility environments such as night, fog, and dust, which cannot meet the driving safety requirements. With the advancement of automobile intelligence, the demand for all-weather environmental perception of automatic driving and advanced auxiliary driving is highlighted, and therefore, infrared optical lenses with high resolution and dense pixels are increasingly favored by people. Although there are many types of current vehicle-mounted infrared lenses, most of them have the following problems: large number of lenses, large volume, low resolution, and small aperture. SUMMARY

[0003] In view of the above problems, the purpose of the present application is 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 has three lenses, includes, along the optical axis from the object side to the imaging surface, in order:

[0006] a first lens with negative focal power, the object side surface of which is a concave surface, and the image side surface of which is a concave surface;

[0007] a second 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;

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

[0009] wherein the real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 0.9<IH / f<1.35.

[0010] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.2<TTL / f<3; 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<TTL / IH<2.7.

[0011] Further preferably, the real image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.85<(IH / 2) / (f x Tan(FOV / 2))<0.95; and the combined focal length f12 of the first lens and the second lens and the focal length f3 of the third lens satisfy: 0<f12 / f3<2.

[0012] It is further preferred that the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 45°<FOV / Fno<70°; and the real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1<IH / EPD<1.6.

[0013] It is further preferred that the half light passing radius d1 of the object side surface of the first lens, the real image height IH corresponding to the maximum field of view of the optical lens, and the maximum field of view FOV of the optical lens satisfy: 1.1<d1 / (IH / 2) / Tan(FOV / 2)<1.9; and the half light passing radius d1 of the object side surface of the first lens and the half light passing radius d6 of the image side surface of the third lens satisfy: 0.9<d1 / d6<1.1.

[0014] It is further preferred that the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.1<f1 / f<-0.6; the object side surface curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: -24<R1 / f<-2.5; and the image side surface curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: 1.6<R2 / f<2.1.

[0015] It is further preferred that the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.5<f2 / f<1; the object side surface curvature radius R3 of the second lens and the effective focal length f of the optical lens satisfy: 3<R3 / f<4.2; and the image side surface curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: -2.4<R4 / f<-1.1.

[0016] It is further preferred that the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.6<f3 / f<19; the object side surface curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: 1.1<R5 / f<2.6; and the image side surface curvature radius R6 of the third lens and the effective focal length f of the optical lens satisfy: 1.1<R6 / f<2.4.

[0017] It is further preferred that the object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: -0.2<(R5-R6) / (R5+R6)<0.2; the object side surface curvature radius R1 of the first lens and the image side surface curvature radius R2 of the first lens satisfy: 0<(R1+R2) / (R1-R2)<1; and the object side surface curvature radius R3 of the second lens and the image side surface curvature radius R4 of the second lens satisfy: 0.1<(R3+R4) / (R3-R4)<0.6.

[0018] Further preferably, a sagittal half-aperture radius of the object side of the first lens Sag1 and a half-aperture radius of the object side of the first lens d1 satisfy: -0.18 < Sag1 / d1 < -0.09; a sagittal half-aperture radius of the image side of the third lens Sag6 and a half-aperture radius of the image side of the third lens d6 satisfy: 0.18 < Sag6 / d6 < 0.24.

[0019] The optical lens provided by the application adopts three 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 such as long focal length, large aperture, and large refractive index of lens material. BRIEF DESCRIPTION OF DRAWINGS

[0020] 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:

[0021] Figure 1 FIG. 1 is a structural schematic diagram of an optical lens according to an embodiment of the present application.

[0022] Figure 2 FIG. 2 is an F-Tan(Theta) distortion curve diagram of the optical lens according to the embodiment of the present application.

[0023] Figure 3 FIG. 3 is an axial aberration curve diagram of the optical lens according to the embodiment of the present application.

[0024] Figure 4 FIG. 4 is an MTF curve diagram of the optical lens according to the embodiment of the present application.

[0025] Figure 5 FIG. 5 is a through-focus MTF curve diagram of the optical lens according to the embodiment of the present application.

[0026] Figure 6 FIG. 6 is a relative illumination curve diagram of the optical lens according to the embodiment of the present application.

[0027] Figure 7 FIG. 7 is a structural schematic diagram of an optical lens according to another embodiment of the present application.

[0028] Figure 8 FIG. 8 is an F-Tan(Theta) distortion curve diagram of the optical lens according to the embodiment of the present application.

[0029] Figure 9 FIG. 9 is an axial aberration curve diagram of the optical lens according to the embodiment of the present application.

[0030] Figure 10 FIG. 10 is an MTF curve diagram of the optical lens according to the embodiment of the present application.

[0031] Figure 11 Focal curve of MTF for the optical lens in embodiment 2 of the present application.

[0032] Figure 12 Relative illuminance curve for the optical lens in embodiment 2 of the present application.

[0033] Figure 13 Structure diagram of the optical lens in embodiment 3 of the present application.

[0034] Figure 14 F-Tan(Theta) distortion curve for the optical lens in embodiment 3 of the present application.

[0035] Figure 15 Axial aberration curve for the optical lens in embodiment 3 of the present application.

[0036] Figure 16 MTF curve for the optical lens in embodiment 3 of the present application.

[0037] Figure 17 Focal curve of MTF for the optical lens in embodiment 3 of the present application.

[0038] Figure 18 Relative illuminance curve for the optical lens in embodiment 3 of the present application.

[0039] Figure 19 Structure diagram of the optical lens in embodiment 4 of the present application.

[0040] Figure 20 F-Tan(Theta) distortion curve for the optical lens in embodiment 4 of the present application.

[0041] Figure 21 Axial aberration curve for the optical lens in embodiment 4 of the present application.

[0042] Figure 22 MTF curve for the optical lens in embodiment 4 of the present application.

[0043] Figure 23 Focal curve of MTF for the optical lens in embodiment 4 of the present application.

[0044] Figure 24 Relative illuminance curve for the optical lens in embodiment 4 of the present application.

[0045] The following detailed description will further describe the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0046] For a better understanding of the present application, various aspects of the present application will be presented in more detail by referring to the attached drawings. It should be understood that these detailed descriptions are merely descriptive of the embodiments of the present application and are not intended in any way to limit the scope of the present application. Throughout the specification, like drawing reference numerals refer to like elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0047] It should be noted that the expressions first, second, third and the like in this specification are used only to distinguish one feature from another feature, and do not indicate any limitation of the features. Thus, the first lens discussed below can also be referred to as a second lens or a third lens without departing from the teachings of the present application.

[0048] 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 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 to scale.

[0049] In this 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.

[0050] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, specify 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. Furthermore, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the word "exemplary" is intended to mean an example or an illustration.

[0051] 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 should 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.

[0052] It should be noted that the embodiments and features of the embodiments in the present application 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.

[0053] The optical lens provided by the embodiment of the present application comprises three lenses, which are sequentially arranged along the optical axis from the object side to the imaging surface as the first lens, the second lens and the third lens.

[0054] In some embodiments, the first lens can have a negative focal power, the object side surface thereof can be a concave surface, and the image side surface thereof can be a concave surface. The second lens can have a positive focal power, the object side surface thereof can be a convex surface, and the image side surface thereof can be a convex surface. The third lens can have a positive focal power, the object side surface thereof can be a convex surface, and the image side surface thereof can be a concave surface.

[0055] In some embodiments, the optical lens can further comprise a diaphragm, which can be located between the second lens and the third lens. It can be understood that the diaphragm is used to limit the amount of light to change the brightness of the imaging. When the diaphragm is located between the second lens and the third lens, the correction of the diaphragm aberration is facilitated.

[0056] In some embodiments, 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: 0.9<IH / f<1.35. Satisfying the above range is helpful to realize a large image surface and improve the imaging quality of the optical lens. More specifically: 1.01<IH / f<1.24.

[0057] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.2<TTL / f<3; 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<TTL / IH<2.7. Satisfying the above range can effectively limit the length of the lens, which is conducive to the optical lens having both miniaturization characteristics and long focal characteristics. At the same time, it is also conducive to realizing large image surface imaging while shortening the total optical length, achieving the balance between miniaturization and large image surface. More specifically: 2.45<TTL / f<2.77; 2.23<TTL / IH<2.51.

[0058] In some embodiments, the real image height IH corresponding to the maximum field of view angle of the optical lens, the effective focal length f of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.85 < (IH / 2) / (f x Tan(FOV / 2)) < 0.95; the combined focal length f12 of the first lens and the second lens and the focal length f3 of the third lens satisfy: 0 < f12 / f3 < 2. Satisfying the above range can control the optical lens to have smaller distortion and improve the imaging quality. Meanwhile, the power of the lens groups before and after the stop of the optical lens is within a suitable range, which can reduce the difficulty of aberration correction of the lens. More specifically: 0.87 < (IH / 2) / (f x Tan(FOV / 2)) < 0.93; 0.06 < f12 / f3 < 1.83.

[0059] In some embodiments, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 45° < FOV / Fno < 70°; the real image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1 < IH / EPD < 1.6. Satisfying the above range can reasonably limit the ratio of the field of view angle to the aperture value, so as to collect light rays of a large angle and obtain good imaging quality. Meanwhile, reasonably limiting the ratio of the image height to the entrance pupil diameter can increase the width of the light ray bundle entering the optical lens, improve the relative luminance, and avoid dark corners. More specifically: 50.42° < FOV / Fno < 64.1°; 1.09 < IH / EPD < 1.48.

[0060] In some embodiments, the half light passing diameter d1 of the object side of the first lens, the real image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 1.1 < d1 / (IH / 2) / Tan(FOV / 2) < 1.9; the half light passing diameter d1 of the object side of the first lens and the half light passing diameter d6 of the image side of the third lens satisfy: 0.9 < d1 / d6 < 1.1. Satisfying the above range can reasonably arrange the overall geometry of the optical lens and improve its structural stability. Meanwhile, reasonably matching the aperture ratio of the first lens and the third lens facilitates structural design. More specifically: 1.18 < d1 / (IH / 2) / Tan(FOV / 2) < 1.74; 0.93 < d1 / d6 < 1.04.

[0061] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.1 < f1 / f < -0.6; the object-side surface curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: -24 < R1 / f < -2.5; and the image-side surface curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: 1.6 < R2 / f < 2.1. Satisfying the above ranges, the proportion of the refractive power of the first lens and the surface shape thereof are reasonably limited, which can slow down the deflection degree of the incident light, help more light enter the optical system in a larger range, and be beneficial to expand the field of view of the lens. More specifically, -1.07 < f1 / f < -0.65; -22.23 < R1 / f < -2.81; and 1.71 < R2 / f < 1.96.

[0062] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.5 < f2 / f < 1; the object-side surface curvature radius R3 of the second lens and the effective focal length f of the optical lens satisfy: 3 < R3 / f < 4.2; and the image-side surface curvature radius R4 of the second lens and the effective focal length f of the optical lens satisfy: -2.4 < R4 / f < -1.1. Satisfying the above ranges, the proportion of the refractive power of the second lens and the surface shape thereof are reasonably limited, which can effectively correct the aberration of the optical lens and improve the imaging quality. More specifically, 0.57 < f2 / f < 0.91; 3.25 < R3 / f < 3.91; and -2.22 < R4 / f < -1.23.

[0063] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.6 < f3 / f < 19; the object-side surface curvature radius R5 of the third lens and the effective focal length f of the optical lens satisfy: 1.1 < R5 / f < 2.6; and the image-side surface curvature radius R6 of the third lens and the effective focal length f of the optical lens satisfy: 1.1 < R6 / f < 2.4. Satisfying the above ranges, the proportion of the refractive power of the third lens and the surface shape thereof are reasonably limited, which is beneficial to improve the relative luminance of the optical lens. More specifically, 1.73 < f3 / f < 17.76; 1.25 < R5 / f < 2.42; and 1.22 < R6 / f < 2.26.

[0064] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -0.2 < (R5-R6) / (R5+R6) < 0.2; the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R2 of the image side surface of the first lens satisfy: 0 < (R1+R2) / (R1-R2) < 1; and the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: 0.1 < (R3+R4) / (R3-R4) < 0.6. Satisfying the above ranges can make the light rays more stable, correct coma and field curvature, improve the flatness of imaging, and improve the imaging quality of the optical lens. More specifically, -0.07 < (R5-R6) / (R5+R6) < 0.04; 0.17 < (R1+R2) / (R1-R2) < 0.87; and 0.27 < (R3+R4) / (R3-R4) < 0.46.

[0065] In some embodiments, the sagittal height Sag1 of the half light passing diameter of the object side surface of the first lens and the half light passing diameter d1 of the object side surface of the first lens satisfy: -0.18 < Sag1 / d1 < -0.09; and the sagittal height Sag6 of the half light passing diameter of the image side surface of the third lens and the half light passing diameter d6 of the image side surface of the third lens satisfy: 0.18 < Sag6 / d6 < 0.24. Satisfying the above ranges helps to control the trend of the edge field of view light rays and highlight the details of the central field of view of the optical lens.

[0066] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.35 < BFL / f < 0.65. Satisfying the above range limits the optical lens to have a suitable back focus, which facilitates reasonable arrangement of the positions of the lenses and reduces the difficulty of processing and assembly.

[0067] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 50° < f x FOV / IH < 60°. Satisfying the above range reasonably limits the relationship between the focal length, the field of view, and the image height of the optical lens, so that the optical lens has good optical performance and can capture details of the subject well. More specifically, 56.82° < f x FOV / IH < 57.97°.

[0068] In some embodiments, the sum ΣCT of the central thicknesses of the first lens to the third lens along the optical axis and the total optical length TTL of the optical lens satisfy: 0.57 < ΣCT / TTL < 0.64. Satisfying the above range controls the total optical length of the optical lens and the sum of the central thicknesses of the lenses within a reasonable range, which helps to achieve high-pixel characteristics and improve the imaging quality of the optical lens.

[0069] In some embodiments, the sum of the central thicknesses of the first lens to the third lens along the optical axis ΣCT and the effective focal length f of the optical lens satisfy: 1.49 < ΣCT / f < 1.68. By satisfying the above range, the effective focal length of the optical lens and the sum of the central thicknesses of the lenses are controlled within a reasonable range, so that the lens can be more compact.

[0070] In some embodiments, the real image height IH corresponding to the maximum field of view angle of the optical lens and the back focal length BFL of the optical lens satisfy: 1.8 < IH / BFL < 3.3. By satisfying the above range, the optical system has a longer back focus, and the distribution of the lenses in the optical lens in space can be reasonably allocated to achieve high pixels. More specifically: 1.89 < IH / BFL < 3.06.

[0071] In some embodiments, the total optical length TTL of the optical lens and the aperture value Fno of the optical lens satisfy: 18 mm < TTL / Fno < 27 mm. By satisfying the above range, the optical lens is limited to have a large aperture. More specifically: 19.21 mm < TTL / Fno < 24.64 mm.

[0072] In some embodiments, the optical lens satisfies the following conditional expressions: 8 mm < f < 10 mm; 55° < FOV < 75°; 7 mm < EPD < 9.5 mm; 20 mm < TTL < 26 mm; 0.9 < Fno < 1.3; 9 mm < IH < 12 mm; 27° < CRA < 30°; 3 mm < BFL < 6 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the real image height corresponding to the maximum field of view angle of the optical lens, CRA represents the chief ray incidence angle at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. By satisfying the above range, the optical lens has at least one or more advantages such as long focal length, large aperture, and large refractive index of lens material. More specifically: 8.92 mm < f < 9.12 mm; 57.9° < FOV < 70.1°; 7.58 mm < EPD < 8.94 mm; 22.09 mm < TTL < 25 mm; 0.99 < Fno < 1.21; 9.18 mm < IH < 11.18 mm; 27.99° < CRA < 28.57°; 3.22 mm < BFL < 5.88 mm.

[0073] 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 low dispersion characteristic of the glass can effectively correct the geometric chromatic aberration of the optical system. More specifically, the optical lens provided by the present application can adopt a full-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0074] In some embodiments, the first lens, the second lens, and the third lens can adopt a spherical lens or an aspherical lens. 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 first lens, the second lens, and the third lens in the present application can all adopt an aspherical lens.

[0075] In various embodiments of the present application, when the lens adopts an aspherical lens, the shape of each aspherical surface of the optical lens satisfies the following equation:

[0076] ;

[0077] 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, and F are the second-order, fourth-order, sixth-order, eighth-order, and tenth-order surface coefficients, respectively.

[0078] The present application will be further described in the following embodiments. In various embodiments, the thickness, the radius of curvature, and the material selection of each lens in the optical lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present application, but the embodiments of the present application are not limited to the following embodiments only, and any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present application should be regarded as equivalent replacement methods, and are included in the protection scope of the present application.

[0079] Embodiment 1

[0080] 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 100 includes, in order from the object side to the imaging surface along the optical axis, a first lens L1, a second lens L2, a diaphragm ST, and a third lens L3.

[0081] The first lens L1 has a negative focal power, the object side surface S1 thereof is a concave surface, and the image side surface S2 thereof is a concave surface.

[0082] The second lens L2 has a positive focal power, the object side surface S3 thereof is a convex surface, and the image side surface S4 thereof is a convex surface.

[0083] The third lens L3 has positive refractive power, the object side S5 is a convex surface, and the image side S6 is a concave surface.

[0084] The imaging surface S7 is a plane.

[0085] The first lens L1, the second lens L2, and the third lens L3 are all glass aspherical lenses.

[0086] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0087] Table 1-1

[0088]

[0089] The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0090] Table 1-2

[0091]

[0092] In this embodiment, the F-Tan(Theta) distortion curve, the axial aberration curve, the MTF curve, the defocus MTF curve, and the relative illumination curve of the optical lens 100 are shown in FIGS. 1-1, 1-2, 1-3, 1-4, and 1-5, respectively. Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6

[0093] Figure 2 FIG. 1-1 shows the F-Tan(Theta) distortion curve of Embodiment 1, which represents the F-Tan(Theta) distortion at different image heights 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 of the optical lens is controlled within -12%~0%, which indicates that the optical lens 100 can well correct the distortion in the infrared waveband.

[0094] Figure 3 FIG. 1-2 shows the axial aberration curve of Embodiment 1, 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 -0.02mm~0.01mm, which indicates that the optical lens 100 can well correct the axial aberration.

[0095] Figure 4 ​The MTF (Modulation Transfer Function) curve of the optical lens 100 of the embodiment 1 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies in each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF value of the embodiment is above 0.2 in the full field of view, and in the range of 0-30 lp / mm, the MTF curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in the case of low frequency and high frequency.

[0096] Figure 5 The defocus MTF (Modulation Transfer Function) curve of the optical lens 100 of the embodiment 1 is shown, which represents the imaging modulation degree of the lens at different focus shifts in each field of view, the horizontal axis represents the focus shift (unit: mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF values of each field of view are small in the case of the same focus shift. And the same focus shift, the meridian and sagittal curves of the same field of view are close, which shows that the astigmatism of the optical lens 100 is small.

[0097] Figure 6 The relative luminance curve of the optical lens 100 of the embodiment 1 is shown, which represents the relative luminance value of the imaging surface at different field angles, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative luminance (unit: %). It can be seen from the figure that the relative luminance value of the optical lens is still greater than 65% at the maximum half field angle, which shows that the optical lens 100 has good relative luminance in the infrared waveband.

[0098] Embodiment 2

[0099] Please refer to Figure 7 , which is a structural schematic diagram of the optical lens 200 provided in the embodiment 2 of the present application. Compared with the embodiment 1, the main difference is that the optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.

[0100] The related parameters of each lens in the optical lens 200 in the embodiment 2 are shown in Table 2-1.

[0101] Table 2-1

[0102]

[0103] The surface type parameters of the aspherical lens of the optical lens 200 in the embodiment 2 are shown in Table 2-2.

[0104] Table 2-2

[0105]

[0106] In this embodiment, the F-Tan(Theta) distortion curve, the axial aberration curve, the MTF curve, the defocus MTF curve and the relative luminance curve of the optical lens 200 are shown inFigure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 As shown.

[0107] from Figure 8 As can be seen, the distortion of the optical lens is controlled within -15% to 0%, indicating that the optical lens 200 can effectively correct distortion in the infrared band.

[0108] from Figure 9 As can be seen, the axial aberration offset is controlled within ±0.02mm, indicating that the optical lens 200 can effectively correct axial aberration.

[0109] from Figure 10 As can be seen, the MTF value of this embodiment is above 0.2 throughout the entire field of view. In the range of 0~30 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0110] from Figure 11 As can be seen, under the same focal shift, the MTF values ​​of each field of view are relatively similar. Furthermore, for the same focal shift, the meridional and sagittal curves of the same field of view are close, indicating that the optical lens 200 has low astigmatism.

[0111] from Figure 12 As can be seen, the relative illumination value of the optical lens is still greater than 60% at the maximum half field of view, indicating that the optical lens 200 has good relative illumination in the infrared band.

[0112] Example 3

[0113] Please see Figure 13 The figure shown is a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

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

[0115] Table 3-1

[0116]

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

[0118] Table 3-2

[0119]

[0120] In the present embodiment, the F-Tan(Theta) distortion curve, the axial aberration curve, the MTF curve, the defocus MTF curve and the relative illumination curve of the optical lens 300 are shown in FIGS. Figure 14 、 Figure 15 、 Figure 16 、 Figure 17 、 Figure 18

[0121] As can be seen from Figure 14 , the distortion of the optical lens is controlled within-12%~0%, which indicates that the optical lens 300 can well correct the distortion in the infrared waveband.

[0122] As can be seen from Figure 15 , the shift of the axial aberration is controlled within ±0.01mm, which indicates that the optical lens 300 can well correct the axial aberration.

[0123] As can be seen from Figure 16 , the MTF value of the present embodiment is above 0.2 in the full field of view, and in the range of 0~30lp / mm, the MTF curve is uniformly and smoothly decreased from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in the case of low frequency and high frequency.

[0124] As can be seen from Figure 17 , in the case of the same focus shift, the MTF values of each field of view have small differences, and the meridian and sagittal curves of the same field of view are close in the case of the same focus shift, which indicates that the astigmatism of the optical lens 300 is small.

[0125] As can be seen from Figure 18 , the relative illumination value of the optical lens is still greater than 70% at the maximum half field of view, which indicates that the optical lens 300 has good relative illumination in the infrared waveband.

[0126] Embodiment 4

[0127] Please refer to Figure 19 , which is a structural schematic diagram of the optical lens 400 provided in the embodiment 4 of the present application, and the main difference between the present embodiment and the embodiment 1 is that the optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.

[0128] The related parameters of each lens in the optical lens 400 in the embodiment 4 are shown in Table 4-1.

[0129] Table 4-1

[0130]

[0131] The surface type parameters of the aspherical lens of the optical lens 400 in the embodiment 4 are shown in Table 4-2.​

[0132] Table 4-2

[0133]

[0134] In the present embodiment, the F-Tan (Theta) distortion curve, the axial aberration curve, the MTF curve, the defocus MTF curve, and the relative illumination curve of the optical lens 400 are shown in FIGS. 4-1 to 4-5, respectively. Figure 20 、 Figure 21 、 Figure 22 、 Figure 23 、 Figure 24

[0135] As can be seen from FIG. 4-1, the distortion of the optical lens is controlled within -8%~0%, which indicates that the optical lens 400 can well correct the distortion in the infrared waveband. Figure 20 As can be seen from FIG. 4-2, the shift of the axial aberration is controlled within -0.01mm~0.02mm, which indicates that the optical lens 400 can well correct the axial aberration.

[0136] Figure 21 As can be seen from FIG. 4-3, the MTF value of the present embodiment is above 0.3 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 in the range of 0~30lp / mm, which indicates that the optical lens 400 has good imaging quality and good detail resolution ability in the low frequency and high frequency cases.

[0137] As can be seen from FIG. 4-4, the MTF values of the various fields of view are less different under the same defocus amount, and the meridian and sagittal curves of the same field of view are close under the same defocus amount, which indicates that the optical lens 400 has small astigmatism. Figure 22 As can be seen from FIG. 4-5, the relative illumination value of the optical lens is still greater than 70% at the maximum half field of view, which indicates that the optical lens 400 has good relative illumination in the infrared waveband.

[0138] Figure 23 Please refer to Table 5-1 and Table 5-2, which are the optical properties corresponding to the above embodiments, including the effective focal length f, the total track length TTL, the aperture value Fno, the chief ray angle of maximum image height CRA, the real image height IH corresponding to the maximum field of view, the maximum field of view FOV, the entrance pupil diameter EPD, the back focal length BFL of the optical lens, and the numerical values corresponding to each conditional expression in each embodiment.

[0139] Table 5-1 Figure 24

[0140]

[0141] Table 5-1

[0142] ​​​​​

[0143] Table 5-2

[0144]

[0145] In summary of the above embodiments, the optical lens provided by the present application adopts three 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 long focal length, large aperture, high refractive index of lens material, etc.

[0146] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0147] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for those skilled in the art, 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 patent of the present application should be subject to the appended claims.

Claims

1. An optical lens, three pieces of lenses in total, characterized in that, In order from the object side to the imaging surface along the optical axis, comprises: a first lens with negative focal length, the object side surface is concave, the image side surface is concave; a second lens with positive focal length, the object side surface is convex, the image side surface is convex; a third lens with positive focal length, the object side surface is convex, the image side surface is concave; Wherein, the real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 0.9 < IH / f < 1.35; the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.2 < TTL / f < 3; 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 < TTL / IH < 2.

7.

2. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.01 < IH / f < 1.24; the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.45 < TTL / f < 2.77; 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: 2.23 < TTL / IH < 2.

51.

3. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens and the maximum field angle FOV of the optical lens satisfy: 0.85 < (IH / 2) / (f*Tan(FOV / 2)) < 0.95; the combined focal length f12 of the first lens and the second lens and the focal length f3 of the third lens satisfy: 0 < f12 / f3 < 2.

4. The optical lens of claim 1, wherein, The maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 45° < FOV / Fno < 70°; 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: 1 < IH / EPD < 1.

6.

5. The optical lens of claim 1, wherein, The half light entrance radius d1 of the object side surface of the first lens, the real image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 1.1 < d1 / (IH / 2) / Tan(FOV / 2) < 1.9; the half light entrance radius d1 of the object side surface of the first lens and the half light entrance radius d6 of the image side surface of the third lens satisfy: 0.9 < d1 / d6 < 1.

1.

6. The optical lens of claim 1, wherein, The focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -1.1 < f1 / f < -0.6; the object side surface curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: -24 < R1 / f < -2.5; the image side surface curvature radius R2 of the first lens and the effective focal length f of the optical lens satisfy: 1.6 < R2 / f < 2.

1.

7. The optical lens of claim 1, wherein, The focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 0.5 8. The optical lens of claim 1, wherein, The focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.6 9. The optical lens of claim 1, wherein, The object side curvature radius R5 of the third lens and the image side curvature radius R6 of the third lens satisfy: -0.2 10. The optical lens of claim 1, wherein, The object side sagittal height Sag1 of the first lens and the object side half aperture radius d1 of the first lens satisfy: -0.18 The image side sagittal height Sag6 of the third lens and the image side half aperture radius d6 of the third lens satisfy: 0.18

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