Optical lens

Abstract

The application provides an optical lens, which comprises seven lenses arranged along an optical axis from an object side to an imaging surface in sequence, wherein the first lens has a negative focal length, and the image side of the first lens is concave; the second lens has a negative focal length, the object side of the second lens is concave, and the image side of the second lens is convex; the third lens has a positive focal length; a diaphragm; the fourth lens has a positive focal length, and the object side and the image side of the fourth lens are both convex; the fifth lens has a positive focal length, and the object side and the image side of the fifth lens are both convex; the sixth lens has a negative focal length, and the object side of the sixth lens is concave; the seventh lens has a negative focal length, the object side of the seventh lens is concave, and the image side of the seventh lens is convex; and the maximum field of view FOV and the aperture value FNO of the optical lens satisfy 40°<FOV / FNO<55°. The optical lens provided by the application improves the resolving power of the optical lens, reduces aberration, and improves the imaging quality of the optical lens through reasonable configuration of the surface shape of each lens and reasonable matching of the focal length.

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 continuous improvement of people's requirements for driving experience, vehicle application type optical lenses are used more and more in intelligent driving, and vehicle optical lenses are constantly improving in the automobile industry.

[0003] Advanced Driver Assistance System (ADAS) plays an important role in intelligent driving, which collects environmental information through various lenses and sensors to ensure the safety of drivers. In addition to the requirements of light, thin, small shape and high pixel, high resolution of the existing ADAS system surround view lens, the optical lens is required to be able to clearly image under low illumination conditions, so it is necessary to develop an optical lens with good imaging effect. SUMMARY

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

[0005] The present application provides an optical lens, which has seven lenses in sequence from the object side to the imaging surface along the optical axis:

[0006] The first lens with negative focal power, the image side is concave;

[0007] The second lens with negative focal power, the object side is concave, and the image side is convex;

[0008] The third lens with positive focal power;

[0009] The diaphragm;

[0010] The fourth lens with positive focal power, the object side and the image side are both convex;

[0011] The fifth lens with positive focal power, the object side and the image side are both convex;

[0012] The sixth lens with negative focal power, the object side is concave;

[0013] The seventh lens with negative focal power, the object side is concave, and the image side is convex;

[0014] The maximum field of view FOV and the aperture value FNO of the optical lens satisfy: 40°<FOV / FNO<55°.

[0015] Further preferably, the total optical length TTL and the effective focal length f of the optical lens satisfy: 6.0<TTL / f<8.0.

[0016] Further preferably, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view angle satisfy: 4.0 < TTL / IH < 5.0.

[0017] Further preferably, the real image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD satisfy: 2.5 < IH / EPD < 3.5.

[0018] Further preferably, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view angle satisfy: 1.4 < IH / f < 1.6.

[0019] Further preferably, the maximum field of view angle FOV of the optical lens, the real image height IH corresponding to the maximum field of view angle, and the light passing aperture D1 of the first lens object side satisfy: 1.5 < D1 / IH / tan(FOV / 2) < 1.8.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.5 < f1 / f < -1.5.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 4.5 < f3 / f < 7.0.

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.6 < f4 / f < 2.0.

[0023] Further preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.6 < f6 / f < -1.0.

[0024] The optical lens provided by the present application improves the resolving power of the optical lens, reduces aberration, and improves the imaging quality of the optical lens by reasonable configuration of each lens surface and reasonable matching of optical power. BRIEF DESCRIPTION OF DRAWINGS

[0025] 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:

[0026] Figure 1 FIG. 1 is a structure diagram of an optical lens according to an embodiment of the present application.

[0027] Figure 2 FIG. 2 is a field curvature curve of the optical lens according to the embodiment of the present application.

[0028] Figure 3 FIG. 3 is an MTF curve of the optical lens according to the embodiment of the present application.

[0029] Figure 4 Axial aberration curve of the optical lens in Embodiment 1 of the present application.

[0030] Figure 5 Vignetting curve of the optical lens in Embodiment 1 of the present application.

[0031] Figure 6 Structure diagram of the optical lens in Embodiment 2 of the present application.

[0032] Figure 7 Curvature of field curve of the optical lens in Embodiment 2 of the present application.

[0033] Figure 8 MTF curve of the optical lens in Embodiment 2 of the present application.

[0034] Figure 9 Axial aberration curve of the optical lens in Embodiment 2 of the present application.

[0035] Figure 10 Vignetting curve of the optical lens in Embodiment 2 of the present application.

[0036] Figure 11 Structure diagram of the optical lens in Embodiment 3 of the present application.

[0037] Figure 12 Curvature of field curve of the optical lens in Embodiment 3 of the present application.

[0038] Figure 13 MTF curve of the optical lens in Embodiment 3 of the present application.

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

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

[0041] Figure 16 Structure diagram of the optical lens in Embodiment 4 of the present application.

[0042] Figure 17 Curvature of field curve of the optical lens in Embodiment 4 of the present application.

[0043] Figure 18 MTF curve of the optical lens in Embodiment 4 of the present application.

[0044] Figure 19 Axial aberration curve of the optical lens in Embodiment 4 of the present application.

[0045] Figure 20A curve of the lateral chromatic aberration of the optical lens in Embodiment 4 of the present application.

[0046] Figure 21 A structure diagram of the optical lens in Embodiment 5 of the present application.

[0047] Figure 22 A curve of the field curvature of the optical lens in Embodiment 5 of the present application.

[0048] Figure 23 A curve of the MTF of the optical lens in Embodiment 5 of the present application.

[0049] Figure 24 A curve of the axial aberration of the optical lens in Embodiment 5 of the present application.

[0050] Figure 25 A curve of the lateral chromatic aberration of the optical lens in Embodiment 5 of the present application.

[0051] Figure 26 A structure diagram of the optical lens in Embodiment 6 of the present application.

[0052] Figure 27 A curve of the field curvature of the optical lens in Embodiment 6 of the present application.

[0053] Figure 28 A curve of the MTF of the optical lens in Embodiment 6 of the present application.

[0054] Figure 29 A curve of the axial aberration of the optical lens in Embodiment 6 of the present application.

[0055] Figure 30 A curve of the lateral chromatic aberration of the optical lens in Embodiment 6 of the present application.

[0056] The following detailed description will further describe the present application with reference to the above-mentioned drawings. DETAILED DESCRIPTION

[0057] 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 understood that the detailed description is merely descriptive of embodiments of the present application and is not intended to limit the scope of the present application in any way. 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.

[0058] It should be noted that the expressions first, second, third, etc. in the present specification are merely 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.

[0059] In the drawings, the thickness, size, and shape of the lenses have been exaggerated slightly for ease of explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0060] In this document, the paraxial region refers to a region near the optical axis. If the 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 the 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 imaging surface is referred to as the image side surface of the lens.

[0061] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, mean that something is included, but do not exclude the presence of one or more additional features, elements, components, and / or combinations thereof. In addition, when describing the embodiments of the present application, the use of "may" means that one or more embodiments of the present application. Also, the word "exemplary" is intended to mean an example or an illustration.

[0062] 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 also be understood that the terms 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.

[0063] 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 conjunction with the embodiments.

[0064] The optical lens according to the embodiments of the present application sequentially comprises, from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a filter, and a protective glass.

[0065] In some embodiments, the first lens can have negative focal power, the image side surface of which is concave; the second lens can have negative focal power, the object side surface of which is concave and the image side surface of which is convex; the third lens can have positive focal power; the fourth lens can have positive focal power, both the object side surface and the image side surface of which are convex; the fifth lens can have positive focal power, both the object side surface and the image side surface of which are convex; and the sixth lens can have negative focal power, the object side surface of which is concave; and the seventh lens can have negative focal power, the object side surface of which is concave and the image side surface of which is convex.

[0066] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value FNO satisfy: 40° < FOV / FNO < 55°. Satisfying the above range is conducive to expanding the field of view of the optical lens and increasing the aperture of the optical lens, which is conducive to the optical lens to obtain more scene information, meets the needs of large-range detection, and the implementation of the large-aperture feature is conducive to improving the problem that the relative luminance of the edge field of view decreases rapidly, thereby also being conducive to obtaining more scene information.

[0067] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f satisfy: 6.0 < TTL / f < 8.0. Satisfying the above requirement ensures sufficient space to adjust the lens structure and optimizes the imaging effect.

[0068] In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view satisfy: 4.0 < TTL / IH < 5.0. Satisfying the above range can effectively balance the demand for a large image surface and lens size of the optical lens.

[0069] In some embodiments, the real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD satisfy: 2.5 < IH / EPD < 3.5. Satisfying the above range can increase the width of the light beam entering the optical lens, so that the brightness of the optical lens at the image surface is improved to avoid dark corners.

[0070] In some embodiments, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view satisfy: 1.4 < IH / f < 1.6. Satisfying the above range can realize high-pixel characteristics and improve the imaging quality of the optical lens.

[0071] In some embodiments, the maximum field of view FOV of the optical lens and the real image height IH corresponding to the maximum field of view and the clear aperture D1 of the object side surface of the first lens satisfy: 1.5 < D1 / IH / tan(FOV / 2) < 1.8. Satisfying the above range can ensure the balance between the size of the optical lens and the large field of view and large image surface.

[0072] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV, and the real image height IH corresponding to the maximum field of view FOV satisfy: 0.7 < (IH / 2) / (f*tan(FOV / 2)) < 0.8. Satisfying the above requirement indicates that the optical distortion of the optical lens is well controlled, and the resolution of the optical lens is improved.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.5 < f1 / f < -1.5. Satisfying the above requirement can make the first lens have appropriate negative refractive power, which is beneficial to reducing the incident light angle and thus reducing the correction difficulty of various aberrations of the optical lens.

[0074] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -16.0 < f2 / f < -8.0. Satisfying the above requirement can make the second lens have appropriate negative refractive power, which can share the negative refractive power of the front end of the optical lens, thereby avoiding excessive light deflection caused by the excessive concentration of the refractive power of the first lens, and reducing the difficulty of chromatic aberration correction of the optical lens.

[0075] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 4.5 < f3 / f < 7.0. Satisfying the above requirement can make the third lens have appropriate positive refractive power, which converges light rays while reducing the light deflection angle, smoothly transitions the light path, balances various aberrations generated by the optical lens, and improves the imaging quality of the optical lens.

[0076] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.6 < f4 / f < 2.0. Satisfying the above requirement can make the fourth lens have appropriate positive refractive power, which converges light rays while reducing the light deflection angle, smoothly transitions the light path, balances various aberrations generated by the optical lens, and improves the imaging quality of the optical lens.

[0077] 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 < 1.9. Satisfying the above requirement can make the fifth lens have appropriate positive refractive power, which converges light rays while reducing the light deflection angle, smoothly transitions the light path, balances various aberrations generated by the optical lens, and improves the imaging quality of the optical lens.

[0078] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.6 < f6 / f < -1.0. Satisfying the above requirement can make the sixth lens have appropriate negative refractive power, which can increase the imaging area of the optical lens; and can also optimize the chromatic aberration of the optical lens and improve the imaging quality of the optical lens.

[0079] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -10.0 < f7 / f < -3.0. Satisfying the above range, the seventh lens can have appropriate negative refractive power, and the imaging area of the optical lens can be increased.

[0080] In some embodiments, the Abbe number Vd of at least one of the fifth lens and the sixth lens satisfies: Vd > 80, and the Abbe number Vd5 of the fifth lens and the Abbe number Vd6 of the sixth lens satisfy: Vd5-Vd6 > 60. Satisfying the above range, the confocal of visible light and infrared light can be achieved.

[0081] In some embodiments, the fifth lens and the sixth lens can be cemented to form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens. In addition, the assembly sensitivity of the optical lens can be reduced, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0082] In some embodiments, the second lens, the fourth lens, and the seventh lens can all adopt the surface type of an aspherical lens to improve the resolution quality.

[0083] In order to make the system have better optical performance, multiple aspherical lenses are used in the lens, and each aspherical surface shape of the optical lens satisfies the following equation:

[0084]

[0085] 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, B, C, D, E, F are the second-order, fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients, respectively.

[0086] 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 preferred embodiments of the application, but the embodiments of the 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 application should be regarded as equivalent replacement methods, and are included in the protection scope of the application.

[0087] Embodiment 1

[0088] Please refer to Figure 1 ​Fig. 1 is a structural schematic diagram of an optical lens provided in Embodiment 1 of the present application, which comprises, along an optical axis from an object side to an imaging plane, a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1 and a protective glass G2.

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

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

[0091] The third lens L3 has a positive focal power, and its object side S5 and its image side S6 are both convex surfaces.

[0092] The stop ST.

[0093] The fourth lens L4 has a positive focal power, and its object side S7 and its image side S8 are both convex surfaces.

[0094] The fifth lens L5 has a positive focal power, and its object side S9 and its image side S10 are both convex surfaces.

[0095] The sixth lens L6 has a negative focal power, and its object side S10 and its image side S11 are both concave surfaces.

[0096] The fifth lens L5 and the sixth lens L6 form a cemented lens group, and the cemented surface S10 is between the image side of the fifth lens L5 and the object side of the sixth lens L6.

[0097] The seventh lens L7 has a negative focal power, and its object side S12 is a concave surface and its image side S13 is a convex surface.

[0098] The object side S14 and the image side S15 of the filter G1 are both flat surfaces.

[0099] The object side S16 and the image side S17 of the protective glass G2 are both flat surfaces.

[0100] The imaging plane S18 is a flat surface.

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

[0102] Table 1-1

[0103]

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

[0105] Table 1-2

[0106]

[0107] In the present embodiment, the field curvature curve, the MTF curve, the axial aberration curve and the lateral chromatic aberration curve of the optical lens are shown in FIGS. 1-4, respectively. Figure 2 、 Figure 3 、 Figure 4 、 Figure 5

[0108] Figure 2 The field curvature curve of Example 1 is shown, which represents the curvature of light rays of different wavelengths 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 field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.03 mm, which shows that the optical lens can well correct the field curvature.

[0109] Figure 3 The MTF (Modulation Transfer Function) curve of Example 1 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 the present embodiment is above 0.35 in the full field of view, and in the range of 0-160 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 ability in low and high frequency conditions.

[0110] Figure 4 The axial aberration curve of Example 1 is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: μm), 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 -10 μm~20 μm, which shows that the optical lens can well correct the axial aberration.

[0111] Figure 5 The lateral chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the lateral 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 figure, the lateral chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2 μm~4.5 μm, which shows that the optical lens can very well correct the chromatic aberration of the edge field of view and the second spectrum of the entire image surface.

[0112] Example 2

[0113] Please refer to Figure 6 ​Figure 1 shows a structural schematic diagram of an optical lens provided in Embodiment 1 of the present application, which comprises, along an optical axis from an object side to an imaging surface, a first lens L1, a second lens L2, a third lens L3, a diaphragm ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1 and a protective glass G2.

[0114] The first lens L1 has a negative focal power, and its object side S1 is a convex surface and its image side S2 is a concave surface.

[0115] The second lens L2 has a negative focal power, and its object side S3 is a concave surface and its image side S4 is a convex surface.

[0116] The third lens L3 has a positive focal power, and its object side S5 is a convex surface and its image side S6 is a concave surface.

[0117] The diaphragm ST.

[0118] The fourth lens L4 has a positive focal power, and its object side S7 and its image side S8 are both convex surfaces.

[0119] The fifth lens L5 has a positive focal power, and its object side S9 and its image side S10 are both convex surfaces.

[0120] The sixth lens L6 has a negative focal power, and its object side S10 and its image side S11 are both concave surfaces.

[0121] The fifth lens L5 and the sixth lens L6 form a cemented lens group, and the cemented surface S10 is formed by the image side of the fifth lens L5 and the object side of the sixth lens L6.

[0122] The seventh lens L7 has a negative focal power, and its object side S12 is a concave surface and its image side S13 is a convex surface.

[0123] The object side S14 and the image side S15 of the filter G1 are both flat surfaces.

[0124] The object side S16 and the image side S17 of the protective glass G2 are both flat surfaces.

[0125] The imaging surface S18 is a flat surface.

[0126] The related parameters of the lenses in the optical lens in Embodiment 2 are shown in Table 2-1.

[0127] Table 2-1

[0128]

[0129] The surface type parameters of the aspherical lenses in the optical lens in Embodiment 2 are shown in Table 2-2.

[0130] Table 2-2

[0131]

[0132] In the present embodiment, the field curvature curve, MTF curve, axial aberration curve and transverse chromatic aberration curve of the optical lens are shown in FIGS. 1-4, respectively. Figure 7 、 Figure 8 、 Figure 9 、 Figure 10

[0133] Figure 7 The field curvature curve of Example 2 is shown, which represents the curvature of light rays of different wavelengths on the meridional image surface and 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 field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.02 mm, which indicates that the optical lens can well correct the field curvature.

[0134] Figure 8 The MTF (Modulation Transfer Function) curve of Example 2 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 the present embodiment is above 0.4 within the full field of view, and within the range of 0-160 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 ability in both low frequency and high frequency cases.

[0135] Figure 9 The axial aberration curve of Example 2 is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: μm), 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 -10 μm~20 μm, which indicates that the optical lens can well correct the axial aberration.

[0136] Figure 10 The transverse chromatic aberration curve of Example 2 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, 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 figure, the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -1 μm~4 μm, which indicates that the optical lens can very well correct the chromatic aberration of the edge field of view and the second spectrum of the entire image surface.

[0137] Example 3

[0138] Please refer to Figure 11 ​Figure 3 shows a structural schematic diagram of an optical lens provided in Embodiment 3 of the present application, which comprises, along an optical axis from an object side to an imaging surface, a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1 and a protective glass G2.

[0139] The first lens L1 has a negative focal power, and its object side S1 is a convex surface and its image side S2 is a concave surface.

[0140] The second lens L2 has a negative focal power, and its object side S3 is a concave surface and its image side S4 is a convex surface.

[0141] The third lens L3 has a positive focal power, and its object side S5 and its image side S6 are both convex surfaces.

[0142] The stop ST.

[0143] The fourth lens L4 has a positive focal power, and its object side S7 and its image side S8 are both convex surfaces.

[0144] The fifth lens L5 has a positive focal power, and its object side S9 and its image side S10 are both convex surfaces.

[0145] The sixth lens L6 has a negative focal power, and its object side S10 and its image side S11 are both concave surfaces.

[0146] The fifth lens L5 and the sixth lens L6 form a cemented lens group, and the cemented surface S10 is formed by the image side of the fifth lens L5 and the object side of the sixth lens L6.

[0147] The seventh lens L7 has a negative focal power, and its object side S12 is a concave surface and its image side S13 is a convex surface.

[0148] The object side S14 and the image side S15 of the filter G1 are both flat surfaces.

[0149] The object side S16 and the image side S17 of the protective glass G2 are both flat surfaces.

[0150] The imaging surface S18 is a flat surface.

[0151] The related parameters of the lenses in the optical lens in Embodiment 3 are shown in Table 3-1.

[0152] Table 3-1

[0153]

[0154] The surface type parameters of the aspheric lenses in the optical lens in Embodiment 3 are shown in Table 3-2.

[0155] Table 3-2

[0156]

[0157] In the present embodiment, the field curvature curve, the MTF curve, the axial aberration curve and the lateral chromatic aberration curve of the optical lens are shown in FIGS. 1-4, respectively. Figure 12 、 Figure 13 、 Figure 14 、 Figure 15

[0158] Figure 12 The field curvature curve of Example 3 is shown, which represents the curvature of light rays of different wavelengths 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 field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.02 mm, which shows that the optical lens can well correct the field curvature.

[0159] Figure 13 The MTF (Modulation Transfer Function) curve of Example 3 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 the present embodiment is above 0.4 in the full field of view, and in the range of 0-160 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 ability in low and high frequency conditions.

[0160] Figure 14 The axial aberration curve of Example 3 is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: μm), 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 -10 μm~15 μm, which shows that the optical lens can well correct the axial aberration.

[0161] Figure 15 The lateral chromatic aberration curve of Example 3 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the lateral 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 figure, the lateral chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2 μm~6 μm, which shows that the optical lens can very well correct the chromatic aberration of the edge field of view and the second spectrum of the entire image surface.

[0162] Example 4

[0163] Please refer to Figure 16 ​Figure 4 shows a structural schematic diagram of an optical lens provided in Embodiment 4 of the present application, which comprises, along an optical axis from an object side to an imaging surface, a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1 and a protective glass G2.

[0164] The first lens L1 has a negative focal power, and its object side S1 is a convex surface and its image side S2 is a concave surface.

[0165] The second lens L2 has a negative focal power, and its object side S3 is a concave surface and its image side S4 is a convex surface.

[0166] The third lens L3 has a positive focal power, and its object side S5 is a concave surface and its image side S6 is a convex surface.

[0167] The stop ST.

[0168] The fourth lens L4 has a positive focal power, and its object side S7 and its image side S8 are both convex surfaces.

[0169] The fifth lens L5 has a positive focal power, and its object side S9 and its image side S10 are both convex surfaces.

[0170] The sixth lens L6 has a negative focal power, and its object side S10 and its image side S11 are both concave surfaces.

[0171] The fifth lens L5 and the sixth lens L6 form a cemented lens group, and the cemented surface S10 is formed by the image side of the fifth lens L5 and the object side of the sixth lens L6.

[0172] The seventh lens L7 has a negative focal power, and its object side S12 is a concave surface and its image side S13 is a convex surface.

[0173] The object side S14 and the image side S15 of the filter G1 are both flat surfaces.

[0174] The object side S16 and the image side S17 of the protective glass G2 are both flat surfaces.

[0175] The imaging surface S18 is a flat surface.

[0176] The related parameters of the lenses in the optical lens in Embodiment 4 are shown in Table 4-1.

[0177] Table 4-1

[0178]

[0179] The surface type parameters of the aspherical lenses in the optical lens in Embodiment 4 are shown in Table 4-2.

[0180] Table 4-2

[0181]

[0182] In the present embodiment, the field curvature curve, the MTF curve, the axial aberration curve and the lateral chromatic aberration curve of the optical lens are shown in FIGS. 1-4, respectively. Figure 17 、 Figure 18 、 Figure 19 、 Figure 20

[0183] Figure 17 The field curvature curve of Example 4 is shown, which represents the curvature of light rays of different wavelengths 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 field curvature of the meridional image surface and the sagittal image surface is controlled within ±0.02 mm, which shows that the optical lens can well correct the field curvature.

[0184] Figure 18 The MTF (Modulation Transfer Function) curve of Example 4 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 the present embodiment is above 0.45 within the full field of view, and within the range of 0-160 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 ability in both low frequency and high frequency cases.

[0185] Figure 19 The axial aberration curve of Example 4 is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: μm), 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 -10 μm~15 μm, which shows that the optical lens can well correct the axial aberration.

[0186] Figure 20 The lateral chromatic aberration curve of Example 4 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the lateral 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 figure, the lateral chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2 μm~6 μm, which shows that the optical lens can very well correct the chromatic aberration of the edge field of view and the second spectrum of the entire image surface.

[0187] Example 5

[0188] Please refer to Figure 21 ​Figure 5 shows a structural schematic diagram of an optical lens provided in Embodiment 5 of the present application, which comprises, along an optical axis from an object side to an imaging plane, a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1 and a protective glass G2.

[0189] The first lens L1 has a negative focal power, and both the object side S1 and the image side S2 thereof are concave;

[0190] The second lens L2 has a negative focal power, and the object side S3 thereof is concave, and the image side S4 thereof is convex;

[0191] The third lens L3 has a positive focal power, and the object side S5 thereof is convex, and the image side S6 thereof is concave;

[0192] The stop ST;

[0193] The fourth lens L4 has a positive focal power, and both the object side S7 and the image side S8 thereof are convex;

[0194] The fifth lens L5 has a positive focal power, and both the object side S9 and the image side S10 thereof are convex;

[0195] The sixth lens L6 has a negative focal power, and both the object side S10 and the image side S11 thereof are concave;

[0196] The fifth lens L5 and the sixth lens L6 constitute a cemented lens group, and the cemented surface S10 is between the image side of the fifth lens L5 and the object side of the sixth lens L6;

[0197] The seventh lens L7 has a negative focal power, and the object side S12 thereof is concave, and the image side S13 thereof is convex;

[0198] Both the object side S14 and the image side S15 of the filter G1 are flat;

[0199] Both the object side S16 and the image side S17 of the protective glass G2 are flat;

[0200] The imaging plane S18 is flat.

[0201] The related parameters of the lenses in the optical lens in Embodiment 5 are shown in Table 5-1.

[0202] Table 5-1

[0203]

[0204] The surface type parameters of the aspheric lenses in the optical lens in Embodiment 5 are shown in Table 5-2.

[0205] Table 5-2

[0206]

[0207] In the present embodiment, the field curvature curve, the MTF curve, the axial aberration curve and the lateral chromatic aberration curve of the optical lens are shown in FIGS. 1-4, respectively. Figure 22 、 Figure 23 、 Figure 24 、 Figure 25

[0208] Figure 22 The field curvature curve of Example 5 is shown, which represents the curvature of light rays of different wavelengths 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 field curvature of the meridional image surface and the sagittal image surface is controlled within -0.03 mm~0.02 mm, which shows that the optical lens can well correct the field curvature.

[0209] Figure 23 The MTF (Modulation Transfer Function) curve of Example 5 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 the present embodiment is above 0.45 within the full field of view, and within the range of 0~160 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 ability in both low frequency and high frequency cases.

[0210] Figure 24 The axial aberration curve of Example 5 is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: μm), 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 -10 μm~20 μm, which shows that the optical lens can well correct the axial aberration.

[0211] Figure 25 The lateral chromatic aberration curve of Example 5 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the lateral 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 figure, the lateral chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2 μm~6 μm, which shows that the optical lens can very well correct the chromatic aberration of the edge field of view and the second spectrum of the entire image surface.

[0212] Example 6

[0213] Please refer to Figure 26 ​Figure 6 shows a structural schematic diagram of an optical lens provided in Embodiment 6 of the present application, which comprises, along an optical axis from an object side to an imaging surface, a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1 and a protective glass G2.

[0214] The first lens L1 has a negative focal power, and its object side S1 is a convex surface, and its image side S2 is a concave surface.

[0215] The second lens L2 has a negative focal power, and its object side S3 is a concave surface, and its image side S4 is a convex surface.

[0216] The third lens L3 has a positive focal power, and its object side S5 is a convex surface, and its image side S6 is a concave surface.

[0217] The stop ST.

[0218] The fourth lens L4 has a positive focal power, and its object side S7 and its image side S8 are both convex surfaces.

[0219] The fifth lens L5 has a positive focal power, and its object side S9 and its image side S10 are both convex surfaces.

[0220] The sixth lens L6 has a negative focal power, and its object side S10 is a concave surface, and its image side S11 is a convex surface.

[0221] The fifth lens L5 and the sixth lens L6 form a cemented lens group, and the cemented surface S10 is between the image side of the fifth lens L5 and the object side of the sixth lens L6.

[0222] The seventh lens L7 has a negative focal power, and its object side S12 is a concave surface, and its image side S13 is a convex surface.

[0223] The object side S14 and the image side S15 of the filter G1 are both flat surfaces.

[0224] The object side S16 and the image side S17 of the protective glass G2 are both flat surfaces.

[0225] The imaging surface S18 is a flat surface.

[0226] The related parameters of the lenses in the optical lens in Embodiment 6 are shown in Table 6-1.

[0227] Table 6-1

[0228]

[0229] The surface type parameters of the aspheric lenses in the optical lens in Embodiment 6 are shown in Table 6-2.

[0230] Table 6-2

[0231]

[0232] In the present embodiment, the field curvature curve, the MTF curve, the axial aberration curve and the lateral chromatic aberration curve of the optical lens are shown in FIGS. 1-4, respectively. Figure 27 、 Figure 28 、 Figure 29 、 Figure 30

[0233] Figure 27 The field curvature curve of Example 6 is shown, which represents the curvature of light rays of different wavelengths 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 field curvature of the meridional image surface and the sagittal image surface is controlled within -0.02mm~0.03mm, which shows that the optical lens can well correct the field curvature.

[0234] Figure 28 The MTF (Modulation Transfer Function) curve of Example 6 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 the present embodiment is above 0.5 within the full field of view, and within the range of 0~160lp / 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 ability in both low frequency and high frequency cases.

[0235] Figure 29 The axial aberration curve of Example 6 is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: μm), 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 -10μm~20μm, which shows that the optical lens can well correct the axial aberration.

[0236] Figure 30 The lateral chromatic aberration curve of Example 6 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55μm) at different image heights on the imaging surface, the horizontal axis represents the lateral 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 figure, the lateral chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -1μm~4μm, which shows that the optical lens can very well correct the chromatic aberration of the edge field of view and the second spectrum of the entire image surface.

[0237] Please refer to Table 7, which is the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, the total optical length TTL, the aperture value FNO, the real image height IH and the maximum field of view FOV of the optical lens, and the numerical values corresponding to each conditional expression in each embodiment.

[0238] ​Table 7

[0239]

[0240] In summary of the above embodiments, the optical lens provided by the present application has infrared confocal function, meets the clarity requirement of daytime and nighttime imaging, improves the resolving power of the optical lens, reduces aberration, and improves the imaging quality of the optical lens through reasonable configuration of each lens surface and reasonable matching of optical power.

[0241] In the description of the present specification, the description referring to 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.

[0242] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An optical lens, in total seven pieces of lenses, characterized in that, In order from the object side to the imaging plane along the optical axis, there are in sequence: a first lens with negative refractive power, whose image side surface is a concave surface; a second lens with negative refractive power, whose object side surface is a concave surface and whose image side surface is a convex surface; a third lens with positive refractive power; a diaphragm; a fourth lens with positive refractive power, whose object side surface and image side surface are both convex surfaces; a fifth lens with positive refractive power, whose object side surface and image side surface are both convex surfaces; a sixth lens with negative refractive power, whose object side surface is a concave surface; a seventh lens with negative refractive power, whose object side surface is a concave surface and whose image side surface is a convex surface; The maximum field of view FOV of the optical lens and the aperture value FNO satisfy: 40°<FOV / FNO<55°. The effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view satisfy: 1.4<IH / f<1.

6.

2. The optical lens of claim 1, wherein, The total optical length TTL of the optical lens and the effective focal length f satisfy: 6.0<TTL / f<8.

0.

3. The optical lens of claim 1, wherein, The total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view satisfy: 4.0<TTL / IH<5.

0.

4. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field of view and the entrance pupil diameter EPD of the optical lens satisfy: 2.5<IH / EPD<3.

5.

5. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -10.0<f7 / f<-3.

0.

6. The optical lens of claim 1, wherein, The maximum field of view FOV of the optical lens, the real image height IH corresponding to the maximum field of view, and the clear aperture D1 of the object side surface of the first lens satisfy: 1.5<D1 / IH / tan(FOV / 2)<1.

8.

7. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.5<f1 / f<-1.

5.

8. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 4.5<f3 / f<7.

0.

9. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.6<f4 / f<2.

0.

10. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.6<f6 / f<-1.0.

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