Optical lens

Abstract

The application provides an optical lens, which comprises six lenses arranged along an optical axis from an object side to an imaging surface in sequence, wherein the first lens has a negative focal power, the object side of the first lens is a convex surface, and the image side of the first lens is a concave surface; the second lens has a positive focal power, the object side of the second lens is a convex surface; the third lens has a positive focal power, the object side of the third lens is a concave surface, and the image side of the third lens is a convex surface; the fourth lens has a negative focal power, the object side of the fourth lens is a convex surface, and the image side of the fourth lens is a concave surface; the fifth lens has a positive focal power, the object side and the image side of the fifth lens are both convex surfaces; the sixth lens has a negative focal power, the object side of the sixth lens is a convex surface, and the image side of the sixth lens is a concave surface; and the object side curvature radius R5 of the third lens and the image side curvature radius R6 of the third lens satisfy 2.2<(R5+R6) / (R5-R6)<3.8. 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 type of each lens and reasonable matching of the focal power.

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 increasing demand for driving experience, vehicle-mounted application optical lenses are increasingly used in intelligent driving, and vehicle-mounted optical lenses are playing an increasingly important role in the automotive industry.

[0003] The camera of the vehicle-mounted DMS system belongs to the imaging camera and is mainly used in the cabin. Its main functions include driver fatigue detection, face recognition and other functions. The existing lens of the DMS system requires not only that the optical lens is thin, has a small front aperture and has high pixel and high resolution, but also that the optical lens can 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 six lenses in total, and the lenses are arranged in order along the optical axis from the object side to the imaging surface as follows:

[0006] The first lens has negative focal power, the object side surface is convex, and the image side surface is concave;

[0007] The second lens has positive focal power, and the object side surface is convex;

[0008] The third lens has positive focal power, the object side surface is concave, and the image side surface is convex;

[0009] The fourth lens has negative focal power, the object side surface is convex, and the image side surface is concave;

[0010] The fifth lens has positive focal power, and both the object side surface and the image side surface are convex;

[0011] The sixth lens has negative focal power, the object side surface is convex, and the image side surface is concave;

[0012] The object side surface curvature radius R5 and the image side surface curvature radius R6 of the third lens satisfy: 2.2<(R5+R6) / (R5-R6)<3.8.

[0013] Further preferably, the object side surface sag Sag3 and the object side surface half aperture radius d3 of the second lens satisfy: 0.1<Sag3 / d3<0.2.

[0014] It is further preferred that the sag height Sag6 of the image side surface of the second lens and the image side half aperture radius d6 satisfy: 0.05 < Sag4 / d4 < 0.15.

[0015] It is further preferred that the total optical length TTL of the optical lens and the central thickness CT3 of the third lens along the optical axis satisfy: 0.1 < CT3 / TTL < 0.25.

[0016] It is further preferred that the total optical length TTL of the optical lens and the effective focal length f satisfy: 4.5 < TTL / f < 5.5.

[0017] It is further preferred that the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view FOV satisfy: 0.4 < (IH / 2) / (f*tan(FOV / 2)) < 0.7.

[0018] It is further preferred that the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view FOV satisfy: 2.0 < IH / f < 2.5.

[0019] It is further preferred that the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.5 < f1 / f < -1.2.

[0020] It is further preferred that the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 4.0 < f2 / f < 10.0.

[0021] It is further preferred that the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2.0 < f3 / f < 3.0.

[0022] The optical lens provided by the present application can effectively limit the length of the lens, is conducive to the miniaturization of the optical lens, and improves the resolving power of the optical lens, reduces aberration, and improves the imaging quality of the optical lens by reasonable configuration of the surface shape of each lens and reasonable matching of the focal power. BRIEF DESCRIPTION OF DRAWINGS

[0023] 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:

[0024] Figure 1 FIG. 1 is a structure diagram of an optical lens according to an embodiment of the present application.

[0025] Figure 2 FIG. 2 is a field curvature curve of the optical lens according to the embodiment of the present application.

[0026] Figure 3 FIG. 3 is an F-Tanθ distortion curve of the optical lens according to the embodiment of the present application.

[0027] Figure 4 MTF curve of the optical lens in Embodiment 1 of the present application.

[0028] Figure 5 Relative illuminance curve of the optical lens in Embodiment 1 of the present application.

[0029] Figure 6 Axial aberration curve of the optical lens in Embodiment 1 of the present application.

[0030] Figure 7 Vignetting curve of the optical lens in Embodiment 1 of the present application.

[0031] Figure 8 Structure diagram of the optical lens in Embodiment 2 of the present application.

[0032] Figure 9 Curvature of field curve of the optical lens in Embodiment 2 of the present application.

[0033] Figure 10 F-Tanθ distortion curve of the optical lens in Embodiment 2 of the present application.

[0034] Figure 11 MTF curve of the optical lens in Embodiment 2 of the present application.

[0035] Figure 12 Relative illuminance curve of the optical lens in Embodiment 2 of the present application.

[0036] Figure 13 Axial aberration curve of the optical lens in Embodiment 2 of the present application.

[0037] Figure 14 Vignetting curve of the optical lens in Embodiment 2 of the present application.

[0038] Figure 15 Structure diagram of the optical lens in Embodiment 3 of the present application.

[0039] Figure 16 Curvature of field curve of the optical lens in Embodiment 3 of the present application.

[0040] Figure 17 F-Tanθ distortion curve of the optical lens in Embodiment 3 of the present application.

[0041] Figure 18 MTF curve of the optical lens in Embodiment 3 of the present application.

[0042] Figure 19 Relative illuminance curve of the optical lens in Embodiment 3 of the present application.

[0043] Figure 20 Axial chromatic aberration curve of the optical lens in Embodiment 3 of the present application.

[0044] Figure 21 Axial chromatic aberration curve of the optical lens in Embodiment 3 of the present application.

[0045] Figure 22 Structure diagram of the optical lens in Embodiment 4 of the present application.

[0046] Figure 23 Field curvature curve of the optical lens in Embodiment 4 of the present application.

[0047] Figure 24 F-Tanθ distortion curve of the optical lens in Embodiment 4 of the present application.

[0048] Figure 25 MTF curve of the optical lens in Embodiment 4 of the present application.

[0049] Figure 26 Relative luminance curve of the optical lens in Embodiment 4 of the present application.

[0050] Figure 27 Axial chromatic aberration curve of the optical lens in Embodiment 4 of the present application.

[0051] Figure 28 Axial chromatic aberration curve of the optical lens in Embodiment 4 of the present application.

[0052] The following detailed description will further describe the present application with reference to the above-mentioned drawings. DETAILED DESCRIPTION

[0053] 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.

[0054] It should be noted that, in the present specification, the expressions first, second, third and the like 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.

[0055] 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 strictly to scale.

[0056] 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 defined, it means that the lens surface is at least convex in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is at least concave in the paraxial region. The surface of each lens closest to the object is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0057] It should also be understood that the words "comprise", "comprising", "has", "having", "include", "including" and / or "contains", "containing", 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. In addition, when expressions such as "at least one of" appear after a list of one or more items, it modifies the entire list of items and does not modify the individual items in the list. In addition, when describing embodiments of the present application, "may" means "one or more embodiments of the present application". Furthermore, the word "exemplary" is intended to mean an example or an illustration.

[0058] 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.

[0059] 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 drawings and in conjunction with the embodiments.

[0060] The optical lens according to the embodiments of the present application comprises, in order 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, and a filter.

[0061] In some embodiments, the first lens can have a negative focal power, which is conducive to reducing the angle of incidence of the incident light, thereby effectively sharing the large field of view on the object side. The object side surface of the first lens is convex, and the image side surface is concave, which is conducive to collecting as much edge field of view light as possible into the rear optical lens, thereby realizing large-angle light collection.

[0062] In some embodiments, the second lens can have positive refractive power, which is conducive to converging light rays while reducing the deflection angle of the light rays, so that the light rays transition smoothly. The object side of the second lens is convex, which balances various aberrations generated by the optical lens and improves the imaging quality of the optical lens.

[0063] In some embodiments, the third lens can have positive refractive power, which is conducive to further converging light rays while reducing the deflection angle of the light rays, so that the light rays transition smoothly. The object side of the third lens is concave, and the image side is convex, which can reduce the influence of spherical aberration and astigmatism generated by the third lens itself on the optical lens, and improve the imaging quality of the optical lens.

[0064] In some embodiments, the fourth lens can have negative refractive power, and the object side thereof is convex, and the image side thereof is concave, which is conducive to balancing various aberrations generated by the optical lens and improving the imaging quality of the optical lens.

[0065] In some embodiments, the fifth lens can have positive refractive power, which is conducive to improving the light converging ability of the optical lens. The object side and the image side of the fifth lens are both convex, which can reduce the spherical aberration and coma generated by the fifth lens itself, and improve the imaging quality of the optical lens.

[0066] In some embodiments, the sixth lens can have negative refractive power, which is conducive to increasing the imaging area of the optical lens and improving the imaging quality of the optical lens. The object side of the sixth lens is convex, and the image side thereof is concave, which can optimize the chromatic aberration of the optical lens and improve the imaging quality of the optical lens.

[0067] In some embodiments, the object side curvature radius R5 and the image side curvature radius R6 of the third lens satisfy: 2.2<(R5+R6) / (R5-R6)<3.8. By adjusting the curvature radii of the object side and the image side of the third lens, the deflection degree of the light rays passing through the lens can be moderated, the influence of the aberration generated by the third lens on the optical lens can be reduced, and the imaging quality of the optical lens can be improved.

[0068] In some embodiments, the object side sag Sag3 and the object side half-diameter of the second lens d3 satisfy: 0.1<Sag3 / d3<0.2. The image side sag Sag6 and the image side half-diameter of the second lens d6 satisfy: 0.05<Sag4 / d4<0.15. By adjusting the surface shape of the edge region of the object side and the image side of the second lens, the off-axis aberration in the optical lens can be corrected, and the imaging quality of the optical lens can be improved.

[0069] In some embodiments, the optical total length TTL of the optical lens and the central thickness CT3 of the third lens along the optical axis satisfy: 0.1 < CT3 / TTL < 0.25. By setting the proportion of the thickness of the third lens in the optical total length to satisfy the above range, the difficulty of lens aberration optimization is reduced, thereby improving the imaging quality of the lens.

[0070] In some embodiments, the optical total length TTL of the optical lens and the effective focal length f satisfy: 4.5 < TTL / f < 5.5. By satisfying the above range, the length of the lens can be effectively limited to achieve miniaturization of the optical lens.

[0071] In some embodiments, the effective focal length f of the optical lens and the maximum field of view FOV and the real image height IH corresponding to the maximum field of view satisfy: 0.4 < (IH / 2) / (f*tan(FOV / 2)) < 0.7. By satisfying the above range, a balance between the size of the field of view and the size of the F-Tanθ distortion of the optical lens is achieved, thereby improving the imaging quality of the optical lens.

[0072] 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: 2.0 < IH / f < 2.5. By satisfying the above range, a balance between the size of the field of view and the size of the F-Tanθ distortion of the optical lens is achieved, thereby improving the imaging quality of the optical lens.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.5 < f1 / f < -1.2. By satisfying the above range, the first lens can have a smaller negative focal power, which is beneficial to increasing the field of view of the optical lens, while making the refraction angle of the incident light change more gently, avoiding excessive refraction changes that produce too much aberration, and improving the imaging quality 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: 4.0 < f2 / f < 10.0. By satisfying the above range, the second lens can have an appropriate positive focal power, which is beneficial to the convergence of light, allowing the divergent light entering the system from the front to smoothly enter the rear optical system, making the light trend more gentle, optimizing the aberration, and improving the resolution.

[0075] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2.0 < f3 / f < 3.0. By satisfying the above range, the third lens can have an appropriate positive focal power, which can reduce the influence of the spherical aberration and astigmatism generated by the third lens itself on the optical lens, thereby improving 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: -1.7 < f4 / f < -1.2. Satisfying the above range can make the fourth lens have appropriate negative refractive power, which is conducive to balancing various aberrations generated by the optical lens and improving 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: 0.8 < f5 / f < 1.0. Satisfying the above range can make the fifth lens have appropriate positive refractive power, which can reduce the spherical aberration and coma generated by the fifth lens itself, and improve 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: -14.5 < f6 / f < -6.0. Satisfying the above range can make the sixth lens have appropriate negative refractive power, which is conducive to increasing the imaging area of the optical lens, and can optimize the chromatic aberration of the optical lens and improve the imaging quality of the optical lens.

[0079] In some embodiments, the maximum field of view FOV of the optical lens satisfies: 115° < FOV < 145°. Satisfying the above range can realize that the optical lens has a large field of view.

[0080] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value FNO satisfy: 50° < FOV / FNO < 75°. 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, meet the demand of large range detection, and the realization of large aperture characteristics is conducive to improving the problem that the relative luminance of the edge field of view decreases rapidly, thereby also conducive to obtaining more scene information.

[0081] 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: 2.0 < TTL / IH < 2.5. Satisfying the above range can effectively balance the demand of the image height of the optical lens and miniaturization.

[0082] 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: 4.0 < IH / EPD < 5.0. 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 plane is improved to avoid dark corners.

[0083] 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 FOV and the clear aperture D1 of the object side surface of the first lens satisfy: 0.3 < D1 / IH / tan(FOV / 2) < 0.7. Satisfying the above range can guarantee the balance between the size of the optical lens and the field of view and the image plane.

[0084] In some embodiments, the fourth lens and the fifth lens can be glued to form a glued 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; and can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0085] In order to make the system have better optical performance, a plurality of aspheric lenses are used in the lens, and each aspheric surface shape of the optical lens satisfies the following equation:

[0086]

[0087] 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 and F are the second-order, fourth-order, sixth-order, eighth-order, tenth-order and twelfth-order curved surface coefficients respectively.

[0088] The application will be further described in the following embodiments. In each embodiment, the thickness, the radius of curvature and the material selection of each lens in the optical lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are only the preferred embodiments of the application, but the embodiments of the application are not limited to the following embodiments, 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.

[0089] Embodiment 1

[0090] Please refer to Figure 1 , which is a structural schematic diagram of the optical lens provided in the embodiment 1 of the application, and the optical lens includes, along the optical axis from the object side to the imaging plane, 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 and a filter G1.

[0091] The first lens L1 has a negative focal power, the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface;

[0092] The second lens L2 has a positive focal power, and the object side surface S3 and the image side surface S4 are both convex surfaces;

[0093] The third lens L3 has positive refractive power, the object side S5 is a concave surface, and the image side S6 is a convex surface;

[0094] The stop ST;

[0095] The fourth lens L4 has negative refractive power, the object side S7 is a convex surface, and the image side S8 is a concave surface;

[0096] The fifth lens L5 has positive refractive power, the object side S8 and the image side S9 are both convex surfaces;

[0097] The fourth lens L4 and the fifth lens L5 form a cemented lens group, that is, the cemented surface of the image side of the fourth lens L4 and the object side of the fifth lens L5 is S8;

[0098] The sixth lens L6 has negative refractive power, the object side S10 is a convex surface, and the image side S11 is a concave surface;

[0099] The object side S12 and the image side S13 of the filter G1 are both flat surfaces;

[0100] The imaging surface S14 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 lens of the optical lens in Embodiment 1 are shown in Table 1-2.

[0105] Table 1-2

[0106] Face number K A B C D E F S1 3.77E+00 0.00E+00 4.90E-03 -5.92E-04 -2.49E-05 4.94E-06 -1.41E-07 S2 -5.69E-01 0.00E+00 8.73E-03 2.63E-03 -7.56E-04 4.70E-04 -9.86E-05 S3 -7.39E+01 0.00E+00 5.96E-03 2.19E-04 2.95E-03 -3.84E-04 -1.40E-04 S4 -6.44E+01 0.00E+00 1.43E-03 9.03E-03 -4.74E-04 6.36E-04 -2.78E-04 S7 1.15E+01 0.00E+00 -3.95E-02 5.22E-02 -6.36E-02 3.47E-02 -7.98E-03 S8 -4.21E+00 0.00E+00 8.68E-02 -4.99E-02 2.02E-02 -5.13E-03 6.02E-04 S9 7.71E-02 0.00E+00 -1.47E-02 9.65E-03 -3.12E-03 6.03E-04 -4.90E-05 S10 -3.85E+00 0.00E+00 -5.83E-02 2.64E-03 4.69E-04 -4.78E-05 -5.55E-06 S11 -1.67E+00 0.00E+00 -7.30E-02 1.32E-02 -1.69E-03 1.17E-04 -3.92E-06

[0107] In this embodiment, the field curvature curve, the F-Tanθ distortion curve, the MTF curve, the relative illumination curve, the axial aberration curve, and the transverse chromatic aberration curve of the optical lens are shown in FIGS. Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 .

[0108] Figure 2 The field curvature curve of Embodiment 1 is shown, which represents the curvature degree 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-0.12mm-0.03mm, which shows that the optical lens can well correct the field curvature.

[0109] Figure 3 The F-Tanθ distortion curve of Example 1 is shown, which represents the F-Tanθ distortion of light rays of different wavelengths at different image heights on the imaging plane. The horizontal axis represents the F-Tanθ distortion (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within -40%~0, and the image compression in the edge angle region is relatively gentle, effectively improving the clarity of the expanded image.

[0110] Figure 4 The MTF (Modulation Transfer Function) curve of Example 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. As can be seen from the figure, the MTF value of the present embodiment is above 0.3 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 field of view, and has good imaging quality and good detail resolution ability in both low and high frequency cases.

[0111] Figure 5 The relative illumination curve of Example 1 is shown, which represents the relative illumination value of different field angles on the imaging plane. The horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 70% at the maximum half field angle, indicating that the optical lens has good relative illumination.

[0112] Figure 6 The axial aberration curve of Example 1 is shown, which represents the axial aberration of each wavelength on the optical axis at the imaging plane. 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 -40μm~20μm, indicating that the optical lens can better correct the axial aberration.

[0113] Figure 7 The sagittal chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength at different image heights on the imaging plane relative to the central wavelength (0.55μm). The horizontal axis represents the sagittal 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 sagittal chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2μm~8μm, indicating that the optical lens can very well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0114] Example 2

[0115] Please refer to Figure 8Figure 2 shows a structural schematic diagram of an optical lens provided in Embodiment 2 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 and a filter G1.

[0116] 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.

[0117] The second lens L2 has a positive focal power, and its object side S3 is a convex surface and its image side S4 is a concave surface.

[0118] 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.

[0119] The stop ST.

[0120] The fourth lens L4 has a negative focal power, and its object side S7 is a convex surface and its image side S8 is a concave surface.

[0121] The fifth lens L5 has a positive focal power, and its object side S8 and its image side S9 are both convex surfaces.

[0122] The fourth lens L4 and the fifth lens L5 form a cemented lens group, and the cemented surface S8 is between the image side of the fourth lens L4 and the object side of the fifth lens L5.

[0123] The sixth lens L6 has a negative focal power, and its object side S10 is a convex surface and its image side S11 is a concave surface.

[0124] The object side S12 and the image side S13 of the filter G1 are both flat surfaces.

[0125] The imaging surface S14 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 aspheric lenses in the optical lens in Embodiment 2 are shown in Table 2-2.

[0130] Table 2-2

[0131] Face number K A B C D E F S1 1.19E+00 0.00E+00 4.41E-03 -6.19E-04 -2.45E-05 5.21E-06 -1.54E-07 S2 -5.72E-01 0.00E+00 8.95E-03 2.35E-03 -6.55E-04 4.87E-04 -1.17E-04 S3 -9.28E+01 0.00E+00 5.79E-03 6.92E-06 2.91E-03 -3.68E-04 -1.37E-04 S4 -9.42E+01 0.00E+00 3.34E-04 8.71E-03 -6.20E-04 6.05E-04 -2.46E-04 S7 1.16E+01 0.00E+00 -4.03E-02 5.17E-02 -6.35E-02 3.48E-02 -8.05E-03 S8 -4.45E+00 0.00E+00 8.57E-02 -5.00E-02 2.01E-02 -5.17E-03 6.13E-04 S9 1.50E-01 0.00E+00 -1.53E-02 9.58E-03 -3.12E-03 6.03E-04 -4.82E-05 S10 -3.90E+00 0.00E+00 -5.76E-02 2.86E-03 4.80E-04 -4.71E-05 -4.65E-06 S11 -1.64E+00 0.00E+00 -7.32E-02 1.32E-02 -1.67E-03 1.19E-04 -4.12E-06

[0132] In this embodiment, the field curvature curve, the F-Tanθ distortion curve, the MTF curve, the relative illumination curve, the axial aberration curve and the transverse chromatic aberration curve of the optical lens are respectively as shown in Figure 9 、 Figure 10、 Figure 11 、 Figure 12 、 Figure 13 、 Figure 14 as shown.

[0133] Figure 9 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 -0.15mm~ -0.03mm, which shows that the optical lens can well correct the field curvature.

[0134] Figure 10 The F-Tanθ distortion curve of Example 2 is shown, which represents the F-Tanθ distortion of light rays of different wavelengths at different image heights on the imaging surface, the horizontal axis represents the F-Tanθ distortion (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within -60%~0, the image compression in the edge angle region is relatively flat, and the clarity of the expanded image is effectively improved.

[0135] Figure 11 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 0.3 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 low frequency and high frequency conditions.

[0136] Figure 12 The relative illumination curve of Example 2 is shown, which represents the relative illumination value of different field angles on the imaging surface, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 70% at the maximum half field angle, which shows that the optical lens has good relative illumination.

[0137] Figure 13 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 -50μm~30μm, which shows that the optical lens can well correct the axial aberration.

[0138] Figure 14The vertical color aberration curve of embodiment 2 is shown, which represents the color aberration of each wavelength at different image heights on the imaging surface relative to the central wavelength (0.55 μm), the horizontal axis represents the vertical color 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 vertical color aberration of the longest wavelength and the shortest wavelength is controlled within -2 μm ~ 10 μm, which shows that the optical lens can well correct the color aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0139] Embodiment 3

[0140] Please refer to Figure 15 , which is a structural schematic diagram of the optical lens provided in embodiment 3 of the present application. Compared with embodiment 2, the main difference of the present embodiment is that the optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.

[0141] The related parameters of each lens in the optical lens in embodiment 3 are shown in Table 3-1.

[0142] Table 3-1

[0143]

[0144] The surface type parameters of the aspherical lens of the optical lens in embodiment 3 are shown in Table 3-2.

[0145] Table 3-2

[0146]

[0147]

[0148] In the present embodiment, the field curvature curve, F-Tanθ distortion curve, MTF curve, relative luminance curve, axial aberration curve, and vertical color aberration curve of the optical lens are shown in Figure 16 , Figure 17 , Figure 18 , Figure 19 , Figure 20 , Figure 21 , respectively.

[0149] Figure 16 The field curvature curve of embodiment 3 is shown, which represents the bending degree 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 -0.12 mm ~ -0.06 mm, which shows that the optical lens can well correct the field curvature.

[0150] Figure 17The F-Tanθ distortion curve of the embodiment 3 is shown, which represents the F-Tanθ distortion of light rays of different wavelengths at different image heights on the imaging plane, the horizontal axis represents the F-Tanθ distortion (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within-50%~0, the image compression in the edge angle region is relatively gentle, and the clarity of the expanded image is effectively improved.

[0151] Figure 18 The MTF (Modulation Transfer Function) curve of the embodiment 3 is shown, which represents the lens imaging modulation degree of different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the embodiment is above 0.3 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 field of view, and has good imaging quality and good detail resolution ability in the case of low frequency and high frequency.

[0152] Figure 19 The relative illumination curve of the embodiment 3 is shown, which represents the relative illumination value of different field angles on the imaging plane, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 70% at the maximum half field angle, which indicates that the optical lens has good relative illumination.

[0153] Figure 20 The axial aberration curve of the embodiment 3 is shown, which represents the axial aberration of each wavelength on the optical axis at the imaging plane, 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-45 μm~40 μm, which indicates that the optical lens can better correct the axial aberration.

[0154] Figure 21 The sagittal chromatic aberration curve of the embodiment 3 is shown, which represents the chromatic aberration of each wavelength at different image heights on the imaging plane relative to the center wavelength (0.55 μm), the horizontal axis represents the sagittal chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field angle. As can be seen from the figure, the sagittal chromatic aberration of the longest wavelength and the shortest wavelength is controlled within-2 μm~10 μm, which indicates that the optical lens can very well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0155] Embodiment 4

[0156] Please refer to Figure 22 , which is a structural schematic diagram of the optical lens provided in the embodiment 4 of the present application. Compared with the embodiment 2, the main difference of the embodiment is that the curvature radius, lens thickness and other optical parameters of each lens surface are different.

[0157] The related parameters of each lens in the optical lens in embodiment 4 are shown in table 4-1.

[0158] Table 4-1

[0159]

[0160] The surface type parameters of the aspherical lens of the optical lens in embodiment 4 are shown in table 4-2.

[0161] Table 4-2

[0162]

[0163]

[0164] In this embodiment, the field curvature curve, F-Tanθ distortion curve, MTF curve, relative illumination curve, axial aberration curve and transverse chromatic aberration curve of the optical lens are shown in FIGS. Figure 23 、 Figure 24 、 Figure 25 、 Figure 26 、 Figure 27 、 Figure 28

[0165] Figure 23 The field curvature curve of embodiment 4 is shown, which represents the curvature degree 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: °). It can be seen from the figure that the field curvature of the meridional image surface and the sagittal image surface is controlled within -0.12mm~ -0.06mm, which shows that the optical lens can well correct the field curvature.

[0166] Figure 24 The F-Tanθ distortion curve of embodiment 4 is shown, which represents the F-Tanθ distortion of light rays of different wavelengths on the imaging surface at different image heights, the horizontal axis represents the F-Tanθ distortion (unit: %), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the F-Tanθ distortion of the optical lens is controlled within -40%~0, the image compression in the edge angle region is relatively flat, and the clarity of the expanded image is effectively improved.

[0167] Figure 25 ​The MTF (Modulation Transfer Function) curve of the optical lens of embodiment 4 is shown, which represents the modulation degree of lens imaging of different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the embodiment is above 0.3 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 capability in the case of low frequency and high frequency.

[0168] Figure 26 The relative illumination curve of embodiment 4 is shown, which represents the relative illumination value of different field angles on the imaging surface, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 70% at the maximum half field angle, which indicates that the optical lens has good relative illumination.

[0169] Figure 27 The axial aberration curve of embodiment 4 is shown, which represents the axial aberration of the optical axis at the imaging surface at each wavelength, 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-50 μm-40 μm, which indicates that the optical lens can better correct the axial aberration.

[0170] Figure 28 The axial aberration curve of embodiment 4 is shown, which represents the axial aberration of the optical axis at the imaging surface at each wavelength, 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-50 μm-40 μm, which indicates that the optical lens can better correct the axial aberration.

[0171] Please refer to Table 5, the optical properties corresponding to each of the above embodiments, including the effective focal length f, the total optical length TTL, the aperture value FNO, the real image height IH and the maximum field of view FOV of the optical lens, and the numerical value corresponding to each conditional expression in each embodiment.

[0172] Table 5

[0173] Parameter and conditional expression Example 1 Example 2 Example 3 Example 4 f (mm) 2.67 2.54 2.81 2.85 FOV (°) 120.00 140.00 130.00 120.00 TTL (mm) 12.76 12.82 13.73 14.42 FNO 2.00 2.00 2.10 2.10 IH (mm) 5.98 5.90 5.92 5.92 EPD (mm) 1.33 1.27 1.34 1.36 CRA (°) 25.33 25.16 22.18 22.96 TTL / f 4.78 5.06 4.88 5.07 TTL / IH 2.13 2.17 2.32 2.44 (IH / 2) / (f x tan(FOV / 2)) 0.65 0.42 0.49 0.60 FOV / FNO (°) 60.00 70.00 61.90 57.14 IH / EPD 4.49 4.65 4.41 4.36 IH / f 2.24 2.33 2.10 2.08 (FOV / 2) / CRA 2.37 2.78 2.93 2.61 FOV*f / IH 53.49 60.16 61.85 57.74 TTL / IH / FOV 0.07 0.06 0.07 0.08 [D1 / IH / tan(FOV / 2)] 0.54 0.35 0.49 0.61 [f1 / f] -1.34 -1.35 -1.35 -1.35 [f2 / f] 4.47 5.52 9.82 7.51 [f3 / f] 2.56 2.62 2.39 2.40 [CAT] f4 / f -1.40 -1.55 -1.48 -1.43 f5 / f 0.88 0.95 0.88 0.88 f6 / f -6.43 -7.42 -13.97 -10.63 (R5+R6) / (R5-R6) 3.61 3.54 2.42 2.41 [Sag3 / d3] 0.13 0.12 0.18 0.16 [Sag4 / d4] 0.08 0.08 0.10 0.12 CT3 / TTL 0.19 0.19 0.17 0.18

[0174] In summary of the above embodiments, the optical lens provided by the present application can effectively limit the length of the lens, which is conducive to the miniaturization of the optical lens, and through the reasonable configuration of each lens surface and the reasonable matching of the optical power, the resolving power of the optical lens is improved, the aberration is reduced, and the imaging quality of the optical lens is improved.

[0175] 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 expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0176] The above-described embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but cannot be understood as a limitation on the patent scope of the present application. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, 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, six pieces of lenses in total, 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 object side surface is a convex surface and whose image side surface is a concave surface; a second lens with positive refractive power, whose object side surface is a convex surface; a third lens with positive refractive power, whose object side surface is a concave surface and whose image side surface is a convex surface; a fourth lens with negative refractive power, whose object side surface is a convex surface and whose image side surface is a concave surface; 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 convex surface and whose image side surface is a concave surface; a radius of curvature R5 of the object side surface of the third lens and a radius of curvature R6 of the image side surface of the third lens satisfy: 2.2<(R5+R6) / (R5-R6)<3.8; an overall optical length TTL of the optical lens and a central thickness CT3 of the third lens along the optical axis satisfy: 0.17≤CT3 / TTL<0.25; an effective focal length f of the optical lens and a focal length f3 of the third lens satisfy: 2.0<f3 / f<3.

0.

2. The optical lens of claim 1, wherein, an object side surface sag height Sag3 of the second lens and an object side surface half-diameter of the light passing radius d3 satisfy: 0.1<Sag3 / d3<0.

2.

3. The optical lens of claim 1, wherein, an image side surface sag height Sag6 of the second lens and an image side surface half-diameter of the light passing radius d6 satisfy: 0.05<Sag4 / d4<0.

15.

4. The optical lens of claim 1, wherein, an overall optical length TTL of the optical lens and a real image height IH corresponding to the maximum field of view angle satisfy: 2.0<TTL / IH<2.

5.

5. The optical lens of claim 1, wherein, an overall optical length TTL of the optical lens and an effective focal length f satisfy: 4.5<TTL / f<5.

5.

6. The optical lens of claim 1, wherein, an effective focal length f of the optical lens, a maximum field of view angle FOV, and a real image height IH corresponding to the maximum field of view angle satisfy: 0.4<(IH / 2) / (f×tan(FOV / 2))<0.

7.

7. The optical lens of claim 1, wherein, an effective focal length f of the optical lens and a real image height IH corresponding to the maximum field of view angle satisfy: 2.0<IH / f<2.

5.

8. The optical lens of claim 1, wherein, an effective focal length f of the optical lens and a focal length f1 of the first lens satisfy: -1.5<f1 / f<-1.

2.

9. The optical lens of claim 1, wherein, an effective focal length f of the optical lens and a focal length f2 of the second lens satisfy: 4.0<f2 / f<10.

0.

10. The optical lens of claim 1, wherein, an effective focal length f of the optical lens and a focal length f5 of the fifth lens satisfy: 0.8<f5 / f<1.0.

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