An optical lens

Abstract

The application discloses an optical lens, which is arranged in sequence along an optical axis from an object side to an image side, and comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens; the first lens is a negative spherical lens; the second lens is a meniscus-shaped aspherical lens with the image side as the concave side; the third lens is a meniscus-shaped aspherical lens with the object side as the concave side; the fourth lens is a positive aspherical lens; the fifth lens is a positive aspherical lens; the sixth lens is a negative aspherical lens; and the seventh lens is a positive aspherical lens; the sixth lens and the seventh lens form a cemented lens, so that the field angle of the optical lens is greater than 110°, and the aperture F# satisfies 0.8<F#<1.2.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of optical imaging technology, and in particular to an optical lens. Background Art

[0002] With the increasing development of security monitoring systems, the requirements for security lenses are becoming increasingly higher, mainly reflected in higher image quality, larger field of view, and larger aperture. Currently, existing ultra-large aperture lenses often have a small field of view. However, in the field of security monitoring, a larger field of view means a wider monitoring range. Therefore, it is necessary to develop an optical lens that can meet the current narrow field of view. Summary of the Invention

[0003] The present invention provides an optical lens to achieve support for ultra-large aperture (0.8 <F#<1.2)的同时,视场角可大于110°。

[0004] To achieve the above object, the present invention provides an optical lens, comprising:

[0005] A first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens are arranged in sequence from the object side to the image side along the optical axis;

[0006] Specifically, the first lens is a spherical lens with negative optical power, the second lens is an aspheric lens with a meniscus shape curved toward the image plane, the third lens is an aspheric lens with a meniscus shape curved toward the object plane, the fourth lens is an aspheric lens with positive optical power, the fifth lens is an aspheric lens with positive optical power, the sixth lens is an aspheric lens with negative optical power, and the seventh lens is an aspheric lens with positive optical power, wherein the sixth lens and the seventh lens constitute a cemented lens.

[0007] Optionally, the first lens is made of glass, the second lens is made of plastic, the third lens is made of plastic, the fourth lens is made of glass, the fifth lens is made of plastic, the sixth lens is made of plastic, and the seventh lens is made of plastic.

[0008] Optionally, a surface of the lens adjacent to the object plane is called the object side surface, and a surface of the lens adjacent to the image plane is called the image side surface;

[0009] The object-side surface of the first lens is convex, and the image-side surface is concave; the object-side surface of the second lens is convex, and the image-side surface is concave; the object-side surface of the third lens is concave, and the image-side surface is convex; the object-side surface of the fourth lens is convex, and the image-side surface is convex; the object-side surface of the fifth lens is convex, and the image-side surface is convex; the object-side surface of the sixth lens is concave, and the image-side surface is concave; the object-side surface of the seventh lens is convex, and the image-side surface is convex.

[0010] Optionally, the first lens and the optical lens satisfy the following relationship: 1.5<|f1 / f|<4.0, wherein f1 is the focal length of the first lens, and f is the focal length of the optical system of the optical lens.

[0011] Optionally, the second lens and the optical lens satisfy the following relationship: |f2 / f|>5, wherein f2 is the focal length of the second lens, and f is the focal length of the optical system of the optical lens.

[0012] Optionally, the second lens satisfies 0.9<|ET2 / CT2|<2.0, wherein ET2 is the thickness of the edge of the second lens along the axial direction, and CT2 is the thickness of the center of the second lens along the axial direction.

[0013] Optionally, the third lens and the optical lens satisfy the following relationship: |f3 / f|>5, wherein f3 is the focal length of the third lens, and f is the optical system focal length of the optical lens.

[0014] Optionally, the fourth lens and the optical lens satisfy the following relationship: 1.5<|f4 / f|<4, wherein f4 is the focal length of the fourth lens, and f is the focal length of the optical system of the optical lens; the refractive index of the fourth lens satisfies nd4>1.6.

[0015] Optionally, the fifth lens and the optical lens satisfy the following relationship: 1.5<|f5 / f|<4, wherein f5 is the focal length of the fifth lens, and f is the focal length of the optical system of the optical lens.

[0016] Optionally, the sixth lens, the seventh lens, and the optical lens satisfy the following relationship: 0.8<|f6 / f|<3, 1<|f7 / f|<4, wherein f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f is the focal length of the optical system of the optical lens;

[0017] The Abbe number of the sixth lens and the Abbe number of the seventh lens satisfy |vd6-vd7|>30.

[0018] According to an embodiment of the present invention, an optical lens is provided by arranging a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in sequence from the object side to the image side along the optical axis; wherein the first lens is a spherical lens with negative optical power, the second lens is an aspherical lens with a meniscus shape curved toward the image plane, the third lens is an aspherical lens with a meniscus shape curved toward the object plane, the fourth lens is an aspherical lens with positive optical power, the fifth lens is an aspherical lens with positive optical power, the sixth lens is an aspherical lens with negative optical power, and the seventh lens is an aspherical lens with positive optical power, wherein the sixth lens and the seventh lens constitute a cemented lens, so that the field of view angle of the optical lens is greater than 110°, the aperture F satisfies, 0.8 <F#<1.2。 BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 1 is a schematic structural diagram of an optical lens according to an embodiment of the present invention;

[0020] Figure 2 is an axial aberration diagram of the optical lens according to an embodiment of the present invention;

[0021] Figure 3 This is a field curvature diagram of the optical lens of an embodiment of the present invention in a wavelength band of 486nm;

[0022] Figure 4 This is a field curvature diagram of the optical lens of an embodiment of the present invention in a wavelength band of 588nm;

[0023] Figure 5 This is a field curvature diagram of the optical lens of an embodiment of the present invention in a wavelength band of 656nm;

[0024] Figure 6 is an optical distortion diagram of the optical lens according to an embodiment of the present invention;

[0025] Figure 7 1 is a schematic structural diagram of an optical lens according to an embodiment of the present invention;

[0026] Figure 8 is an axial aberration diagram of an optical lens according to an embodiment of the present invention;

[0027] Figure 9 This is a field curvature diagram of an optical lens according to an embodiment of the present invention in a wavelength band of 486 nm;

[0028] Figure 10 This is a field curvature diagram of an optical lens according to an embodiment of the present invention in a wavelength band of 588 nm;

[0029] Figure 11 This is a field curvature diagram of an optical lens according to an embodiment of the present invention in a wavelength band of 656 nm;

[0030] Figure 12is an optical distortion diagram of the optical lens of one embodiment of the present application;

[0031] Figure 13 is a structural diagram of the optical lens of another embodiment of the present application;

[0032] Figure 14 is an axial aberration diagram of the optical lens of another embodiment of the present application;

[0033] Figure 15 is a field curvature diagram of the optical lens of another embodiment of the present application at a wavelength of 486 nm;

[0034] Figure 16 is a field curvature diagram of the optical lens of another embodiment of the present application at a wavelength of 588 nm;

[0035] Figure 17 is a field curvature diagram of the optical lens of another embodiment of the present application at a wavelength of 656 nm;

[0036] Figure 18 is an optical distortion diagram of the optical lens of another embodiment of the present application. DETAILED DESCRIPTION

[0037] The present application will be further described below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures.

[0038] Figure 1 is a structural diagram of the optical lens of an embodiment of the present application. As shown in Figure 1 , the optical lens comprises:

[0039] a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6 and a seventh lens 7 arranged in sequence along the optical axis from the object side to the image side;

[0040] Among them, the first lens 1 is a negative spherical lens, the second lens 2 is a meniscus-shaped non-spherical lens curved toward the image side, the third lens 3 is a meniscus-shaped non-spherical lens curved toward the object side, the fourth lens 4 is a positive non-spherical lens, the fifth lens 5 is a positive non-spherical lens, the sixth lens 6 is a negative non-spherical lens, and the seventh lens 7 is a positive non-spherical lens, wherein the sixth lens 6 and the seventh lens 7 constitute a cemented lens.

[0041] It can be understood that the optical power is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam, and it characterizes the ability of the optical system to deflect light. The larger the absolute value of the optical power, the stronger the ability to bend light, and the smaller the absolute value of the optical power, the weaker the ability to bend light. When the optical power is a positive number, the refraction of light is convergent; when the optical power is a negative number, the refraction of light is divergent. The optical power can be applied to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be applied to characterize a certain lens, and can also be applied to characterize a system formed by multiple lenses (i.e., a lens group). In this embodiment, each lens can be fixed to a lens barrel ( Figure 1 (not shown in the figure), by reasonably allocating the optical power of the lens, the imaging effect of the large aperture fixed focus lens is better, where the optical power is the reciprocal of the focal length.

[0042] It should be noted that the optical power of the second lens 2 and the third lens 3 is not limited. In other words, the center thickness and edge thickness of the second lens 2 and the third lens 3 can be set according to actual conditions, as long as the curvature of the image side and the object side is guaranteed.

[0043] Optionally, the first lens 1 may be made of glass, the second lens 2 may be made of plastic, the third lens 3 may be made of plastic, the fourth lens 4 may be made of glass, the fifth lens 5 may be made of plastic, the sixth lens 6 may be made of plastic, and the seventh lens 7 may be made of plastic.

[0044] Optionally, the surface of the lens adjacent to the object plane is the object side surface, and the surface of the lens adjacent to the image plane is the image side surface;

[0045] The object-side surface of the first lens 1 is convex, and the image-side surface is concave; the object-side surface of the second lens 2 is convex, and the image-side surface is concave; the object-side surface of the third lens 3 is concave, and the image-side surface is convex; the object-side surface of the fourth lens 4 is convex, and the image-side surface is convex; the object-side surface of the fifth lens 5 is convex, and the image-side surface is convex; the object-side surface of the sixth lens 6 is concave, and the image-side surface is concave; the object-side surface of the seventh lens 7 is convex, and the image-side surface is convex.

[0046] Optionally, the first lens 1 and the optical lens satisfy the following relationship: 1.5 < |f1 / f| < 4.0, where f1 is the focal length of the first lens 1 and f is the focal length of the optical system of the optical lens. The first lens 1 functions to collect light, and its negative focal power is suitable for lenses with a relatively large field of view. Furthermore, the first lens 1 is a spherical glass lens with excellent physical and chemical properties and greater adaptability to the environment.

[0047] Optionally, the second lens 2 and the optical lens satisfy the following relationship: |f2 / f|>5, where f2 is the focal length of the second lens 2, and f is the optical system focal length of the optical lens.

[0048] Optionally, the second lens 2 satisfies 0.9<|ET2 / CT2|<2.0, where ET2 is the thickness of the edge of the second lens 2 along the axial direction, and CT2 is the thickness of the center of the second lens 2 along the axial direction.

[0049] The second lens element 2 is mainly used to correct on-axis aberrations. The second lens element 2 satisfies 0.9<|ET2 / CT2|<2.0, ensuring that the second lens element 2 has good manufacturability.

[0050] Optionally, the third lens 3 and the optical lens satisfy the following relationship: |f3 / f|>5, where f3 is the focal length of the third lens 3, and f is the optical system focal length of the optical lens.

[0051] The third lens 3 is mainly used to correct off-axis aberrations.

[0052] Optionally, the fourth lens 4 and the optical lens satisfy the following relationship: 1.5<|f4 / f|<4, where f4 is the focal length of the fourth lens 4 and f is the focal length of the optical system of the optical lens; the refractive index of the fourth lens 4 satisfies nd4>1.6.

[0053] The position of the fourth lens element 4 is advantageous for correcting spherical aberration and coma, and a focal length within this range helps to control the size of the lens and ensure a large aperture.

[0054] Optionally, the fifth lens 5 and the optical lens satisfy the following relationship: 1.5<|f5 / f|<4, where f5 is the focal length of the fifth lens 5, and f is the focal length of the optical system of the optical lens.

[0055] The fifth lens 5 is mainly used to further correct off-axis aberrations.

[0056] Optionally, the sixth lens 6, the seventh lens 7 and the optical lens satisfy the following relationship: 0.8<|f6 / f|<3, 1<|f7 / f|<4, where f6 is the focal length of the sixth lens 6, f7 is the focal length of the seventh lens 7, and f is the focal length of the optical system of the optical lens;

[0057] The Abbe number of the sixth lens 6 and the Abbe number of the seventh lens 7 satisfy |vd6-vd7|>30. The sixth lens 6 and the seventh lens 7 can be cemented together to better correct chromatic aberration.

[0058] It should be noted that the aperture of the optical lens is F, 0.8 <F<1.2;视场角大于110°,像高0.85<ImgH / EFL<1.35,其中ImgH表示镜头半像高,EFL表示镜头焦距。

[0059] In an exemplary embodiment, the sum of the distances ΣT between any two adjacent lenses on the optical axis from the first lens 1 to the seventh lens 7, the distance TD from the object side surface of the first lens 1 to the image side surface of the seventh lens 7 on the optical axis, and the distance BFL from the image side surface of the seventh lens 7 to the image plane on the optical axis satisfy the conditional expression: 0.8 <BFL*ΣT / TD<2。通过满足此条件式,有利于合理分配轴上空间,在降低光学系统总体长度与提高成像品质之间取得良好的平衡。

[0060] The optical lens proposed by the present invention is described below with reference to specific embodiments.

[0061] Example 1

[0062] like Figure 1 As shown, the optical lens includes:

[0063] A first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, and a seventh lens 7 are arranged in sequence along the optical axis from the object side to the image side;

[0064] Among them, the first lens 1 is a spherical lens with negative optical power, the second lens 2 is an aspheric lens with a meniscus shape curved toward the image plane, the third lens 3 is an aspheric lens with a meniscus shape curved toward the object plane, the fourth lens 4 is an aspheric lens with positive optical power, the fifth lens 5 is an aspheric lens with positive optical power, the sixth lens 6 is an aspheric lens with negative optical power, and the seventh lens 7 is an aspheric lens with positive optical power, wherein the sixth lens 6 and the seventh lens 7 form a cemented lens. The object-side surface of the first lens 1 is convex, and the image-side surface is concave; the object-side surface of the second lens 2 is convex, and the image-side surface is concave; the object-side surface of the third lens 3 is concave, and the image-side surface is convex; the object-side surface of the fourth lens 4 is convex, and the image-side surface is convex; the object-side surface of the fifth lens 5 is convex, and the image-side surface is convex; the object-side surface of the sixth lens 6 is concave, and the image-side surface is concave; the object-side surface of the seventh lens 7 is convex, and the image-side surface is convex.

[0065] The refractive power of the second lens 2 is negative, and the refractive power of the third lens 3 is negative.

[0066] By configuring the fourth lens element (4) as a glass aspheric lens, its refractive index is increased, thereby increasing the degree of light bending, thereby shortening the overall optical length of the large-aperture fixed-focus lens. Furthermore, by rationally configuring the second, third, fifth, sixth, and seventh lenses as plastic aspheric lenses, and the first lens element (1) as a glass spherical lens, optical system performance is ensured while effectively controlling costs. The uniform shape and thickness of each lens element fully guarantee its processability.

[0067] A stop 8 is further provided between the third lens 3 and the fourth lens 4 .

[0068] Furthermore, the focal lengths of the first lens 1 to the seventh lens 7 satisfy the following conditions:

[0069] Table 1

[0070] f1＝-9.5 |f1 / f|=2.9 f2＝-60.1 |f2 / f|=18.2 f3＝-17.8 |f3 / f|=5.3 f4＝6.67 |f4 / f|=2.0 f5＝9.9 |f5 / f|=3.0 f6＝-4.9 |f6 / f|=1.5 f7＝4.7 |f7 / f|=1.4

[0071] Among them, f1 represents the focal length of the first lens 1, f2 represents the focal length of the second lens 2, f3 represents the focal length of the third lens 3, f4 represents the focal length of the fourth lens 4, f5 represents the focal length of the fifth lens 5, f6 represents the focal length of the sixth lens 6, f7 represents the focal length of the seventh lens 7, and f represents the focal length of the optical lens.

[0072] Table 2: Design values ​​of an optical lens (f=3.3mm, aperture F#=1.0):

[0073]

[0074]

[0075] The surface numbers in Table 2 are numbered according to the order of the surfaces of each lens, where "S1" represents the front surface of the first lens 1, "S2" represents the back surface of the first lens 1, and so on; the radius of curvature represents the degree of curvature of the lens surface, with a positive value indicating that the surface is curved toward the image plane, and a negative value indicating that the surface is curved toward the object plane, where "PL" represents that the surface is flat and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the light deflection ability of the material between the current surface and the next surface, and a blank space represents that the current position is air with a refractive index of 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface, and a blank space represents that the current position is air; the K value represents the numerical value of the best-fit conic coefficient of the aspheric surface.

[0076] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0077]

[0078] Among them, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the curvature radius; k is the fitting cone coefficient; AF is the 4th, 6th, 8th, 10th, 12th, and 14th order of the aspheric polynomial.

[0079] Table 3 A design value of each aspheric parameter in the optical lens

[0080] Surface number A B C D E F S3 -2.04E-03 -4.11E-04 -2.76E-05 8.99E-07 2.82E-07 -1.41E-08 S4 2.56E-03 -4.57E-04 -2.04E-04 3.20E-05 -1.47E-06 -8.76E-09 S5 -1.02E-02 -2.89E-05 4.90E-05 -1.14E-05 3.28E-06 -3.75E-07 S6 9.71E-04 -2.03E-04 -1.11E-05 6.90E-06 -6.26E-07 9.23E-09 S8 1.22E-03 -8.50E-05 1.12E-05 -6.22E-07 -5.90E-09 4.70E-10 S9 1.05E-03 -6.23E-05 7.71E-06 -2.22E-07 -1.57E-08 4.81E-10 S10 3.37E-03 -2.15E-04 1.27E-06 1.09E-06 -9.47E-08 2.99E-09 S11 -8.39E-04 1.23E-04 1.28E-05 -9.06E-07 -9.55E-08 6.61E-09 S12 -2.23E-03 1.24E-04 1.84E-05 -1.19E-06 -1.29E-07 6.58E-09 S13 2.32E-03 -6.30E-04 1.01E-04 3.18E-06 -5.02E-07 -1.86E-08 S14 -6.95E-03 8.00E-04 5.90E-06 -5.19E-06 3.33E-08 1.90E-08

[0081] Wherein, -2.04E-03 represents the coefficient A of the surface No. S3 is -2.04*10 -3 .

[0082] Figure 2 is the axial aberration diagram of the optical lens of the embodiment of the present application. The horizontal coordinate represents the distance between the light and the focal point of the optical axis to the image plane, in mm; the vertical coordinate represents the maximum entrance pupil radius normalization, without unit; the offset variation of three wavelengths with the entrance pupil position is distinguished by the solid and dashed lines, wherein the three wavelengths of the light are 0.486 μm, 0.587 μm and 0.656 μm, respectively, and the three wavelengths are distinguished by the solid line, the dashed line and the dotted line, respectively. Figure 2 It can be seen that the optical lens provided by the embodiment effectively controls the chromatic aberration on the axis of spherical aberration, secondary spectrum and other aberrations from the light with a wavelength of 486 nm to the light with a wavelength of 656 nm.

[0083] Figure 3 is the field curvature diagram of the optical lens of the embodiment of the present application at a wavelength of 486 nm; Figure 4 is the field curvature diagram of the optical lens of the embodiment of the present application at a wavelength of 588 nm; Figure 5 is the field curvature diagram of the optical lens of the embodiment of the present application at a wavelength of 656 nm; wherein the horizontal coordinate represents the size of the field curvature, in mm; the vertical coordinate represents the normalized image height, without unit; wherein T represents the meridian, and S represents the arc loss. Figures 3 to 5 It can be seen that the optical lens provided by the embodiment is effectively controlled on the field curvature from the light with a wavelength of 486 nm to the light with a wavelength of 656 nm.

[0084] Figure 6 is the optical distortion diagram of the optical lens of the embodiment of the present application. The horizontal coordinate represents the size of the distortion, in %; the vertical coordinate represents the normalized image height, without unit; and Figure 6 It can be seen that the optical distortion of the optical lens provided by the embodiment is less than 58% for the light with a wavelength of 587 nm.

[0085] Embodiment Two

[0086] As shown in Figure 7 , the optical lens comprises:

[0087] a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a sixth lens 16 and a seventh lens 17 arranged in sequence along the optical axis from the object side to the image side;

[0088] The first lens 11 is a spherical lens with negative optical power, the second lens 12 is an aspheric lens with a meniscus shape curved toward the image plane, the third lens 13 is an aspheric lens with a meniscus shape curved toward the object plane, the fourth lens 14 is an aspheric lens with positive optical power, the fifth lens 15 is an aspheric lens with positive optical power, the sixth lens 16 is an aspheric lens with negative optical power, and the seventh lens 17 is an aspheric lens with positive optical power. The sixth lens 16 and the seventh lens 17 form a cemented lens. The object-side surface of the first lens 11 is convex and the image-side surface is concave; the object-side surface of the second lens 12 is convex and the image-side surface is concave; the object-side surface of the third lens 13 is concave and the image-side surface is convex; the object-side surface of the fourth lens 14 is convex and the image-side surface is convex; the object-side surface of the fifth lens 15 is convex and the image-side surface is convex; the object-side surface of the sixth lens 16 is concave and the image-side surface is concave; and the object-side surface of the seventh lens 17 is convex and the image-side surface is convex.

[0089] The refractive power of the second lens 12 is positive, and the refractive power of the third lens 13 is negative.

[0090] By configuring the fourth lens 14 as a glass aspheric lens, its refractive index is increased, thereby increasing the degree of light bending, thereby shortening the overall optical length of the large-aperture fixed-focus lens. Furthermore, by rationally configuring the second, third, fifth, sixth, and seventh lenses as plastic aspheric lenses, and the first lens 11 as a glass spherical lens, optical system performance is ensured while effectively controlling costs. The uniform shape and thickness of each lens ensures full processability.

[0091] A stop 18 is further provided between the third lens 13 and the fourth lens 14 .

[0092] Furthermore, the focal lengths of the first lens 11 to the seventh lens 17 satisfy the following conditions:

[0093] Table 4

[0094] f1＝-8.24 |f1 / f|=2.1 f2＝121 |f2 / f|=30.3 f3＝-37.2 |f3 / f|=9.3 f4＝8.14 |f4 / f|=2.0 f5＝12.8 |f5 / f|=3.2 f6＝-5.15 |f6 / f|=1.3 f7＝5.35 |f7 / f|=1.3

[0095] Among them, f1 represents the focal length of the first lens 11, f2 represents the focal length of the second lens 12, f3 represents the focal length of the third lens 13, f4 represents the focal length of the fourth lens 14, f5 represents the focal length of the fifth lens 15, f6 represents the focal length of the sixth lens 16, f7 represents the focal length of the seventh lens 17, and f represents the focal length of the optical lens.

[0096] Table 5: Design values ​​of an optical lens (f = 4.0 mm, aperture F# = 1.15)

[0097] Surface number Face shape Radius of curvature thickness Refractive index Abbe number K value S1 spherical surface 30.60 0.97 1.59 68.6 S2 spherical surface 4.17 0.97 S3 Aspheric 2.84 1.45 1.54 55.7 -0.76 S4 Aspheric 2.44 3.88 -1.17 S5 Aspheric -4.39 1.45 1.64 23.9 -3.94 S6 Aspheric -6.08 0.61 -2.15 aperture flat unlimited 0.00 S8 Aspheric 19.77 3.03 1.81 40.7 16.76 S9 Aspheric -9.14 0.61 -5.87 S10 Aspheric 12.48 3.03 1.54 55.7 4.17 S11 Aspheric -13.91 0.24 -13.82 S12 Aspheric -27.51 1.21 1.66 20.3 -5.00 S13 Aspheric 3.97 3.64 1.54 55.7 -4.32 S14 Aspheric -6.99 4.27 -11.97

[0098] The surface numbers in Table 5 are numbered according to the order of the surfaces of each lens, where "S1" represents the front surface of the first lens 11, "S2" represents the back surface of the first lens 11, and so on; the radius of curvature represents the degree of curvature of the lens surface, a positive value represents that the surface is curved toward the image plane, and a negative value represents that the surface is curved toward the object plane, where "PL" represents that the surface is flat and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the light deflection ability of the material between the current surface and the next surface, and a blank space represents that the current position is air with a refractive index of 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface, and a blank space represents that the current position is air; the K value represents the numerical value of the best-fit conic coefficient of the aspheric surface.

[0099] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0100]

[0101] Among them, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the curvature radius; k is the fitting cone coefficient; AF is the 4th, 6th, 8th, 10th, 12th, and 14th order of the aspheric polynomial.

[0102] Table 6 A design value of each aspheric parameter in the optical lens

[0103] Surface number A B C D E F S3 -1.49E-03 4.78E-06 -2.06E-05 1.56E-07 8.28E-08 -3.32E-09 S4 6.12E-04 -3.65E-04 -3.30E-05 5.84E-06 -3.85E-07 9.35E-09 S5 -5.04E-03 1.54E-04 1.30E-05 -3.40E-06 4.81E-07 -3.99E-08 S6 9.88E-04 -6.88E-06 3.25E-06 1.03E-06 -1.77E-07 5.05E-09 S8 1.09E-03 -1.86E-05 3.84E-06 -1.14E-07 -5.82E-09 1.96E-10 S9 5.86E-04 -6.39E-06 3.95E-06 6.20E-08 3.24E-09 -2.80E-10 S10 1.72E-03 -7.37E-05 9.10E-07 2.08E-07 -1.28E-08 3.20E-10 S11 -6.61E-04 -2.63E-05 3.77E-07 -1.84E-07 -5.43E-09 1.12E-09 S12 -1.96E-03 4.91E-05 2.18E-06 -4.44E-07 -2.20E-08 2.21E-09 S13 1.70E-03 -1.52E-04 2.37E-05 -1.57E-07 -9.25E-08 2.91E-09 S14 -2.83E-03 2.45E-04 -2.75E-06 -6.61E-07 4.09E-08 -5.23E-10

[0104] Among them, -1.49E-03 means that the coefficient A of the surface number S3 is -1.49*10 -3 .

[0105] Figure 8 This is an axial aberration diagram of an optical lens according to an embodiment of the present invention. The horizontal coordinate represents the distance from the light ray and the optical axis focus to the image plane, in mm; the vertical coordinate represents the normalized maximum entrance pupil radius, without units; the three wavelengths are distinguished by the virtual and real lines as they change with the entrance pupil position. The three wavelengths of light are 0.486μm, 0.587μm, and 0.656μm, respectively. Figure 6 It can be seen that, in the optical lens provided in this embodiment, aberrations such as chromatic aberration and secondary spectrum on the spherical aberration axis are effectively controlled from light with a wavelength of 486 nm to light with a wavelength of 656 nm.

[0106] Figure 9 This is a field curvature diagram of the optical lens of an embodiment of the present invention in a wavelength band of 486nm; Figure 10 This is a field curvature diagram of the optical lens of an embodiment of the present invention in a wavelength band of 588nm; Figure 11This is a field curvature diagram of the optical lens of an embodiment of the present invention in the wavelength band of 656nm; wherein the horizontal coordinate represents the magnitude of the field curvature, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; wherein T represents the meridian, and S represents the arc loss; Figures 9 to 11 It can be seen that the optical lens provided in this embodiment is effectively controlled in terms of field curvature from light with a wavelength of 486 nm to light with a wavelength of 656 nm.

[0107] Figure 12 This is an optical distortion diagram of an optical lens according to an embodiment of the present invention. The horizontal coordinate represents the magnitude of the distortion, in %; the vertical coordinate represents the normalized image height, without unit; Figure 12 It can be seen that the optical distortion of the optical lens provided in this embodiment for light with a wavelength of 587 nm is less than 44%.

[0108] Example 3

[0109] like Figure 13 As shown, the optical lens includes:

[0110] A first lens 21, a second lens 22, a third lens 23, a fourth lens 24, a fifth lens 25, a sixth lens 26 and a seventh lens 27 are arranged in sequence from the object side to the image side along the optical axis;

[0111] The first lens 21 is a spherical lens with negative optical power, the second lens 22 is an aspheric lens with a meniscus shape curved toward the image plane, the third lens 23 is an aspheric lens with a meniscus shape curved toward the object plane, the fourth lens 24 is an aspheric lens with positive optical power, the fifth lens 25 is an aspheric lens with positive optical power, the sixth lens 26 is an aspheric lens with negative optical power, and the seventh lens 27 is an aspheric lens with positive optical power. The sixth lens 26 and the seventh lens 27 form a cemented lens. The object-side surface of the first lens 21 is convex and the image-side surface is concave; the object-side surface of the second lens 22 is convex and the image-side surface is concave; the object-side surface of the third lens 23 is concave and the image-side surface is convex; the object-side surface of the fourth lens 24 is convex and the image-side surface is convex; the object-side surface of the fifth lens 25 is convex and the image-side surface is convex; the object-side surface of the sixth lens 26 is concave and the image-side surface is concave; and the object-side surface of the seventh lens 27 is convex and the image-side surface is convex.

[0112] The optical power of the second lens 22 is positive, and the optical power of the third lens 23 is negative.

[0113] By setting the fourth lens 24 as a glass aspheric lens, the refractive index of the fourth lens 24 is increased, and the bending degree of the light is increased, so that the total length of the large aperture focusing lens is shortened. By reasonably setting the second, third, fifth, sixth and seventh lenses as plastic aspheric lenses, and the first lens 21 as a glass spherical lens, the performance of the optical system is ensured, and the cost is effectively controlled. The thickness of each lens shape is uniform, which fully ensures the lens processing property.

[0114] In addition, a diaphragm 28 is arranged between the third lens 23 and the fourth lens 24.

[0115] Further, the focal lengths of the first lens 21 to the seventh lens 27 satisfy the following conditions:

[0116] Table 7

[0117]

[0118]

[0119] Wherein, f1 represents the focal length of the first lens 21, f2 represents the focal length of the second lens 22, f3 represents the focal length of the third lens 23, f4 represents the focal length of the fourth lens 24, f5 represents the focal length of the fifth lens 25, f6 represents the focal length of the sixth lens 26, f7 represents the focal length of the seventh lens 27, and f represents the focal length of the optical lens.

[0120] Table 8 Design values of an optical lens (f = 2.8 mm, aperture F# = 1.2)

[0121] Surface number Face shape Radius of curvature thickness Refractive index Abbe number K value S1 spherical surface 22.03 0.68 1.59 68.6 S2 spherical surface 2.99 0.57 S3 Aspheric 1.95 1.02 1.54 55.7 -0.88 S4 Aspheric 1.61 2.65 -1.04 S5 Aspheric -3.34 1.02 1.64 23.9 -3.84 S6 Aspheric -3.32 0.42 -2.20 aperture flat PL 0.00 S8 Aspheric 17.73 2.12 1.81 40.7 31.37 S9 Aspheric -9.61 0.42 5 S10 Aspheric 8.45 2.12 1.54 55.7 3.27 S11 Aspheric -6.88 0.17 -40.42 S12 Aspheric -11.09 0.85 1.66 20.3 -5.00 S13 Aspheric 2.54 2.55 1.54 55.7 -10.41 S14 Aspheric -3.57 3.06 -6.85

[0122] The surface numbers in Table 8 are numbered according to the surface order of each lens, wherein "S1" represents the front surface of the first lens 21, "S2" represents the rear surface of the first lens 21, and so on; the radius of curvature represents the bending degree of the lens surface, the positive value represents that the surface bends to the image side, and the negative value represents that the surface bends to the object side, wherein "PL" represents that the surface is a plane, and the radius of curvature is infinite; the thickness represents the center axis distance from the current surface to the next surface; the refractive index represents the deflection ability of the material between the current surface and the next surface; the space represents that the current position is air, and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface, and the space represents that the current position is air; the K value represents the numerical value of the best fitting conic coefficient of the aspheric surface.

[0123] The aspheric conic coefficient can be defined by the following aspheric formula, but is not limited to the following representation method:

[0124]

[0125] Among them, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the curvature radius; k is the fitting cone coefficient; AF is the 4th, 6th, 8th, 10th, 12th, and 14th order of the aspheric polynomial.

[0126] Table 9 A design value of each aspheric parameter in the optical lens

[0127] Surface number A B C D E F S3 -3.92E-03 -2.85E-04 -4.04E-04 4.53E-06 6.16E-06 -3.61E-07 S4 -2.85E-03 -3.50E-03 -6.28E-04 2.12E-04 -1.26E-05 1.06E-07 S5 -4.33E-03 2.91E-03 3.61E-04 -1.38E-04 1.48E-05 -6.74E-07 S6 7.46E-03 1.35E-03 1.94E-04 2.23E-05 -1.28E-05 7.19E-07 S8 4.87E-03 -7.90E-05 4.36E-05 -3.80E-06 -3.55E-07 2.58E-08 S9 1.12E-03 1.70E-04 4.08E-05 -9.86E-09 3.17E-07 -2.25E-08 S10 5.20E-03 -4.89E-04 8.35E-06 5.94E-06 -4.95E-07 2.83E-08 S11 -3.52E-03 -3.45E-04 -3.46E-06 -5.12E-06 4.35E-09 1.34E-07 S12 -6.90E-03 2.20E-04 1.05E-05 -1.26E-05 -1.24E-06 2.47E-07 S13 5.35E-03 -2.34E-03 9.04E-04 -9.49E-05 -7.97E-07 2.11E-07 S14 -8.96E-03 1.39E-03 -9.78E-06 -1.96E-05 1.90E-06 -1.22E-08

[0128] Among them, -3.92E-03 means that the coefficient A of the surface number S3 is -3.92*10 -3 .

[0129] Figure 14 This is an axial aberration diagram of an optical lens according to another embodiment of the present invention. The horizontal coordinate represents the distance from the light ray and the optical axis focus to the image plane, in mm; the vertical coordinate represents the normalized maximum entrance pupil radius, without units; the three wavelengths are distinguished by the virtual and real lines as they change with the entrance pupil position. The three wavelengths of light are 0.486μm, 0.587μm, and 0.656μm, respectively. Figure 14 It can be seen that, in the optical lens provided in this embodiment, aberrations such as chromatic aberration and secondary spectrum on the spherical aberration axis are effectively controlled from light with a wavelength of 486 nm to light with a wavelength of 656 nm.

[0130] Figure 15 This is a field curvature diagram of the optical lens of an embodiment of the present invention in a wavelength band of 486nm; Figure 16 This is a field curvature diagram of the optical lens of an embodiment of the present invention in a wavelength band of 588nm; Figure 17 This is a field curvature diagram of the optical lens of an embodiment of the present invention in the wavelength band of 656nm; wherein the horizontal coordinate represents the magnitude of the field curvature, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; wherein T represents the meridian, and S represents the arc loss; Figures 15 to 17 It can be seen that the optical lens provided in this embodiment is effectively controlled in terms of field curvature from light with a wavelength of 486 nm to light with a wavelength of 656 nm.

[0131] Figure 18 This is an optical distortion diagram of another embodiment of the present invention. The horizontal coordinate represents the magnitude of the distortion, in %; the vertical coordinate represents the normalized image height, without unit; Figure 18 It can be seen that the optical distortion of the optical lens provided in this embodiment is less than 58% for light with a wavelength of 587 nm.

[0132] In summary, according to the optical lens proposed by the present invention, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens are arranged in sequence along the optical axis from the object side to the image side; wherein the first lens is a spherical lens with negative optical power, the second lens is an aspherical lens with a meniscus shape curved toward the image plane, the third lens is an aspherical lens with a meniscus shape curved toward the object plane, the fourth lens is an aspherical lens with positive optical power, the fifth lens is an aspherical lens with positive optical power, the sixth lens is an aspherical lens with negative optical power, and the seventh lens is an aspherical lens with positive optical power, wherein the sixth lens and the seventh lens constitute a cemented lens, so that the field of view of the optical lens is greater than 110°, the aperture F# satisfies, 0.8 <F#<1.2。

[0133] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. An optical lens, characterized in that: include: A first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens are arranged in sequence from the object side to the image side along the optical axis; The first lens is a spherical lens with negative optical power, the second lens is an aspheric lens with a meniscus shape curved toward the image plane, the third lens is an aspheric lens with a meniscus shape curved toward the object plane, the fourth lens is an aspheric lens with positive optical power, the fifth lens is an aspheric lens with positive optical power, the sixth lens is an aspheric lens with negative optical power, and the seventh lens is an aspheric lens with positive optical power, wherein the sixth lens and the seventh lens form a cemented lens; The sixth lens, the seventh lens, and the optical lens satisfy the following relationship: 0.8<|f6 / f|<3, 1<|f7 / f|<4, wherein f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f is the focal length of the optical system of the optical lens; The refractive index of the fourth lens satisfies nd4>1.6; The aperture F of the optical lens satisfies 0.8 <F<1.2。 2. The optical lens according to claim 1, wherein: The first lens is made of glass, the second lens is made of plastic, the third lens is made of plastic, the fourth lens is made of glass, the fifth lens is made of plastic, the sixth lens is made of plastic, and the seventh lens is made of plastic.

3. The optical lens according to claim 1, wherein: The surface of the lens adjacent to the object plane is the object side surface, and the surface of the lens adjacent to the image plane is the image side surface; The object-side surface of the first lens is convex, and the image-side surface is concave; the object-side surface of the second lens is convex, and the image-side surface is concave; the object-side surface of the third lens is concave, and the image-side surface is convex; the object-side surface of the fourth lens is convex, and the image-side surface is convex; the object-side surface of the fifth lens is convex, and the image-side surface is convex; the object-side surface of the sixth lens is concave, and the image-side surface is concave; the object-side surface of the seventh lens is convex, and the image-side surface is convex.

4. The optical lens according to any one of claims 1 to 3, wherein: The first lens and the optical lens satisfy the following relationship: 1.5<|f1 / f|<4.0, wherein f1 is the focal length of the first lens, and f is the focal length of the optical system of the optical lens.

5. The optical lens according to any one of claims 1 to 3, wherein: The second lens and the optical lens satisfy the following relationship: |f2 / f|>5, wherein f2 is the focal length of the second lens, and f is the focal length of the optical system of the optical lens.

6. The optical lens according to any one of claims 1 to 3, wherein: The second lens satisfies 0.9<|ET2 / CT2|<2.0, wherein ET2 is the thickness of the edge of the second lens along the axial direction, and CT2 is the thickness of the center of the second lens along the axial direction.

7. The optical lens according to any one of claims 1 to 3, wherein: The third lens and the optical lens satisfy the following relationship: |f3 / f|>5, wherein f3 is the focal length of the third lens, and f is the focal length of the optical system of the optical lens.

8. The optical lens according to any one of claims 1 to 3, wherein: The fourth lens and the optical lens satisfy the following relationship: 1.5<|f4 / f|<4, wherein f4 is the focal length of the fourth lens, and f is the focal length of the optical system of the optical lens.

9. The optical lens according to any one of claims 1 to 3, wherein: The fifth lens and the optical lens satisfy the following relationship: 1.5<|f5 / f|<4, wherein f5 is the focal length of the fifth lens, and f is the focal length of the optical system of the optical lens.

10. The optical lens according to any one of claims 1 to 3, characterized in that: The Abbe number of the sixth lens and the Abbe number of the seventh lens satisfy |vd6-vd7|>30.

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