A fixed-focus lens

Abstract

An embodiment of the present invention discloses a fixed-focus lens. The fixed-focus lens includes: a first lens with a negative optical power, a second lens with a negative optical power, a third lens with a positive optical power, a diaphragm, a fourth lens with a positive optical power, a fifth lens with a positive optical power, a sixth lens with a negative optical power, a seventh lens with a positive optical power, an eighth lens with a positive optical power or a negative optical power, and a ninth lens with a positive optical power or a negative optical power, which are arranged in sequence along the optical axis from the object side to the image side; the fifth lens, the sixth lens, and the seventh lens are three-piece cemented lenses; the second lens is an aspherical lens. The fixed-focus lens provided by the embodiment of the present invention can achieve the effects of a large aperture, a large target surface, and high pixels.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of optical imaging, and in particular, to a fixed-focus lens. Background Art

[0002] With the progress of technology and the development of 5G, higher requirements are put forward for the performance of lenses in all aspects in all walks of life, such as resolution, high and low temperature confocal, and low-light photography. Generally, a camera can only obtain high-pixel pictures in places with good lighting conditions, while in low-light conditions, an infrared fill light or other auxiliary light sources need to be added, which will cause various light pollutions and result in a great loss of the photographing effect. Summary of the Invention

[0003] The embodiments of the present invention provide a fixed-focus lens which does not require a fill light under low-light conditions and can ensure the effect of a large image plane and a large aperture with high quality.

[0004] The embodiments of the present invention provide a fixed-focus lens, which includes: a first lens with a negative optical power, a second lens with a negative optical power, a third lens with a positive optical power, a diaphragm, a fourth lens with a positive optical power, a fifth lens with a positive optical power, a sixth lens with a negative optical power, a seventh lens with a positive optical power, an eighth lens with a positive or negative optical power, and a ninth lens with a positive or negative optical power, which are arranged in sequence from the object side to the image side along the optical axis;

[0005] The fifth lens, the sixth lens, and the seventh lens are three-piece cemented lenses; the second lens is an aspherical lens.

[0006] Optionally, the object side surface of the first lens is convex, and the image side surface of the first lens is concave; the object side surface of the second lens is concave, and the image side surface of the second lens is convex; the object side surface of the third lens is convex, and the image side surface of the third lens is convex or concave; the object side surface of the fourth lens is convex or concave, and the image side surface of the fourth lens is concave or convex; the object side surface of the fifth lens is convex, and the image side surface of the fifth lens is concave; the object side surface of the sixth lens is concave, and the image side surface of the sixth lens is concave; the object side surface of the seventh lens is convex, and the image side surface of the seventh lens is convex; the object side surface of the eighth lens is convex or concave, and the image side surface of the eighth lens is convex or concave; the object side surface of the ninth lens is convex or concave, and the image side surface of the ninth lens is convex or concave.

[0007] Optionally, the first lens, the third lens, the fifth lens, the sixth lens, and the seventh lens are all glass spherical lenses;

[0008] The second lens, the eighth lens, and the ninth lens are all plastic aspherical lenses;

[0009] The fourth lens is a glass spherical lens or a plastic aspherical lens.

[0010] Optionally, the optical power of the first lens and the optical power of the fixed-focus lens satisfy

[0011] where is the optical power of the fixed-focus lens, is the optical power of the first lens.

[0012] Optionally, the optical power of the first lens and the thickness of the first lens satisfy

[0013] where is the optical power of the first lens, and D1 is the thickness of the first lens;

[0014] and the refractive index Nd1 of the first lens satisfies Nd1 > 1.7.

[0015] Optionally, the optical power of the second lens and the optical power of the fixed-focus lens satisfy

[0016] where is the optical power of the fixed-focus lens, is the optical power of the second lens.

[0017] Optionally, the refractive index Nd2 of the second lens satisfies 1.5 ≤ Nd2 ≤ 1.7.

[0018] Optionally, the third lens is a glass spherical lens or a plastic aspherical lens, and the fourth lens is a glass spherical lens or a plastic aspherical lens;

[0019] and the optical power of the third lens and the optical power of the fourth lens satisfy:

[0020] where is the optical power of the third lens, is the optical power of the fourth lens.

[0021] Optionally, the Abbe numbers of the fifth lens, the sixth lens, and the seventh lens satisfy respectively: Vd5 - Vd6 > 20, Vd7 - Vd6 > 20;

[0022] where Vd5 is the Abbe number of the fifth lens, Vd6 is the Abbe number of the sixth lens, and Vd7 is the Abbe number of the seventh lens.

[0023] Optionally, the thickness of the eighth lens, the thickness of the ninth lens, and the optical power of the fixed-focus lens satisfy

[0024] Among them, D8 is the thickness of the eighth lens, and D9 is the thickness of the ninth lens. is the optical power of the fixed-focus lens.

[0025] The fixed-focus lens provided by the embodiment of the present invention is provided with a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power, a diaphragm, a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with positive or negative optical power, and a ninth lens with positive or negative optical power, which are arranged in sequence from the object side to the image side along the optical axis; among them, the second lens is an aspherical lens, which can correct the field curvature brought by a large image plane, and the fifth, sixth, and seventh lenses form a triplet lens group, which can correct the chromatic aberration brought by a large aperture, realizing a fixed-focus lens with a large image plane and a large aperture; at the same time, it has a large target surface and high pixels, and can match the largest 1 / 1.1-inch ultra-large target surface sensor chip, and can meet up to 12 million pixels. Description of the Drawings

[0026] Figure 1 is a schematic structural diagram of a fixed-focus lens provided by an embodiment of the present invention;

[0027] Figure 2 is Figure 1 the axial aberration curve of the fixed-focus lens shown;

[0028] Figure 3 is Figure 1 the field curvature curve of the fixed-focus lens shown;

[0029] Figure 4 is Figure 1 the distortion curve of the fixed-focus lens shown;

[0030] Figure 5 is Figure 1 the chromatic aberration curve of the fixed-focus lens shown;

[0031] Figure 6 is a schematic structural diagram of another fixed-focus lens provided by an embodiment of the present invention;

[0032] Figure 7 is Figure 6 the axial aberration curve of the fixed-focus lens shown;

[0033] Figure 8 is Figure 6 the field curvature curve of the fixed-focus lens shown;

[0034] Figure 9 is Figure 6The distortion curve of the fixed-focus lens shown;

[0035] Figure 10 is Figure 6 The chromatic aberration curve of the fixed-focus lens shown;

[0036] Figure 11 is a schematic structural diagram of another fixed-focus lens provided by an embodiment of the present invention;

[0037] Figure 12 is Figure 11 The axial aberration curve of the fixed-focus lens shown;

[0038] Figure 13 is Figure 11 The field curvature curve of the fixed-focus lens shown;

[0039] Figure 14 is Figure 11 The distortion curve of the fixed-focus lens shown;

[0040] Figure 15 is Figure 11 The chromatic aberration curve of the fixed-focus lens shown. Detailed implementation manners

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention rather than all structures are shown in the accompanying drawings.

[0042] Figure 1 is a schematic structural diagram of a fixed-focus lens provided by an embodiment of the present invention. As Figure 1 shown, the fixed-focus lens provided by the embodiment of the present invention includes: a first lens 11 with a negative optical power, a second lens 12 with a negative optical power, a third lens 13 with a positive optical power, a diaphragm 20, a fourth lens 14 with a positive optical power, a fifth lens 15 with a positive optical power, a sixth lens 16 with a negative optical power, a seventh lens 17 with a positive optical power, an eighth lens 18 with a positive or negative optical power, and a ninth lens 19 with a positive or negative optical power, which are arranged in sequence from the object side to the image side along the optical axis; the fifth lens 15, the sixth lens 16, and the seventh lens 17 are three-piece cemented lenses; the second lens 12 is an aspherical lens.

[0043] Among them, the optical power is equal to the difference between the converging degree of the image-side light beam and the converging degree of the object-side light beam, which characterizes the ability of the optical system to deflect light rays. The greater the absolute value of the optical power, the stronger the bending ability of the light rays; the smaller the absolute value of the optical power, the weaker the bending ability of the light rays. When the optical power is positive, the refraction of the light rays is convergent; when the optical power is negative, the refraction of the light rays is divergent. The optical power can be used to characterize a certain refracting surface of a lens (i.e., a surface of the lens), can be used to characterize a certain lens, or can be used to characterize a system formed by multiple lenses (i.e., a lens group). In this embodiment, each lens can be fixed in a lens barrel ( Figure 1 not shown), and by reasonably distributing the optical power of the lenses, the imaging effect of the optical lens is good, where the optical power is the reciprocal of the focal length.

[0044] In this embodiment, by reasonably distributing the optical power ratios of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, the seventh lens 17, the eighth lens 18, and the ninth lens 19, and at the same time by setting the second lens 12 as an aspherical lens, the field curvature caused by a large image plane can be corrected, and the fifth lens 15, the sixth lens 16, and the seventh lens 17 form a triple cemented lens group, which can correct the chromatic aberration caused by a large aperture and increase the field of view angle, so that the fixed-focus lens provided by the embodiment of the present invention can be used in combination with a day-night full-color camera, and has the characteristics of a large aperture (for example, FNO.≤1.11), a large target surface, and high pixels, and can match a sensor chip with a maximum size of 1 / 1.1 inches at most, and can meet 12 million pixels at most.

[0045] In addition, an aperture 20 is provided between the third lens 13 and the fourth lens 14, which can improve the imaging quality. It should be noted that the present application does not specifically limit the position of the aperture, and those skilled in the art can set the position of the aperture according to the actual situation.

[0046] At the same time, since the fifth lens 15, the sixth lens 16, and the seventh lens 17 form a triple cemented lens group, the volume of the fixed-focus lens can be further reduced, realizing the miniaturization of the fixed-focus lens.

[0047] Optionally, continue to refer to Figure 1, the object side of the first lens 11 is convex, and the image side of the first lens 11 is concave; the object side of the second lens 12 is concave, and the image side of the second lens 12 is convex; the object side of the third lens 13 is convex, and the image side of the third lens 13 is convex or concave; the object side of the fourth lens 14 is convex or concave, and the image side of the fourth lens 14 is concave or convex; the object side of the fifth lens 15 is convex, and the image side of the fifth lens 15 is concave; the object side of the sixth lens 16 is concave, and the image side of the sixth lens 16 is concave; the object side of the seventh lens 17 is convex, and the image side of the seventh lens 17 is convex; the object side of the eighth lens 18 is convex or concave, and the image side of the eighth lens 18 is convex or concave; the object side of the ninth lens 19 is convex or concave, and the image side of the ninth lens 19 is convex or concave.

[0048] Optionally, the first lens 11, the third lens 13, the fifth lens 15, the sixth lens 16 and the seventh lens 17 are all glass spherical lenses; the second lens 12, the eighth lens 18 and the ninth lens 19 are all plastic aspherical lenses; the fourth lens 14 is a glass spherical or plastic aspherical lens.

[0049] The fixed-focus lens provided by the embodiment of the present invention adopts a combination of glass lenses and plastic lenses. Such a setting can reduce costs and improve performance, and can meet the use conditions of -40°C to 80°C, that is, reduce costs while improving the performance of the lens.

[0050] Optionally, the optical power of the first lens 11 and the optical power of the fixed-focus lens satisfy wherein, is the optical power of the fixed-focus lens, is the optical power of the first lens. That is, the incident aperture of the light is compressed by the first lens 11 to reduce aberration.

[0051] Optionally, the optical power of the first lens 11 and the thickness of the first lens 11 satisfy wherein, is the optical power of the first lens, D1 is the thickness of the first lens; and the refractive index Nd1 of the first lens 11 satisfies Nd1 > 1.7. The advantage of such a setting is that the incident aperture of the light can be further compressed and the aberration can be further reduced.

[0052] Optionally, the optical power of the second lens 12 and the optical power of the fixed-focus lens satisfy wherein, is the optical power of the fixed-focus lens, is the optical power of the second lens. That is, the field curvature can be corrected by the second lens 12.

[0053] Optionally, the refractive index Nd2 of the second lens 12 satisfies 1.5 ≤ Nd2 ≤ 1.7. The advantage of such a setting is that the field curvature can be further corrected.

[0054] Optionally, the third lens 13 is a glass spherical lens or a plastic aspherical lens, and the fourth lens 14 is a glass spherical lens or a plastic aspherical lens; and the optical power of the third lens 13 and the optical power of the fourth lens 14 satisfy: Wherein, is the optical power of the third lens, is the optical power of the fourth lens. With such a setting, spherical aberration can be corrected. Optionally, the refractive index Nd3 of the third lens 13 can be set to be greater than the refractive index Nd4 of the fourth lens 14 to further correct spherical aberration.

[0055] Optionally, the Abbe numbers of the fifth lens 15, the sixth lens 16, and the seventh lens 17 respectively satisfy: Vd5 - Vd6 > 20, Vd7 - Vd6 > 20; where Vd5 is the Abbe number of the fifth lens, Vd6 is the Abbe number of the sixth lens, and Vd7 is the Abbe number of the seventh lens. In this way, the ability to correct chromatic aberration can be improved to a certain extent, and thus the imaging quality of the fixed-focus lens can be improved.

[0056] Optionally, the thickness of the eighth lens 18, the thickness of the ninth lens 19, and the optical power of the fixed-focus lens satisfy Where D8 is the thickness of the eighth lens, D9 is the thickness of the ninth lens, is the optical power of the fixed-focus lens.

[0057] By setting the eighth lens 18 and the ninth lens 19 as plastic aspherical lenses, and the thickness D8 of the eighth lens 18, the thickness D9 of the ninth lens 19, and the optical power of the fixed-focus lens satisfy spherical aberration can be corrected and the lens aperture can be increased in design for high and low temperatures.

[0058] Next, specific examples will be combined to further describe the fixed-focus lens provided by the embodiments of the present invention. It should be noted that the following examples do not limit the present application.

[0059] Exemplarily: Continuing to refer to Figure 1 , in this embodiment, Figure 1 in the fixed-focus lens shown, the radius of curvature, the center thickness (i.e., the distance between the center points of adjacent mirror surfaces), the refractive index, and the K value of each lens along the optical axis from the object side to the image side satisfy the conditions listed in Table 1:

[0060] Table 1 is a set of design values of the fixed-focus lens:

[0061] Surf Radius of Curvature (mm) Thickness (mm) Refractive Index K Value S1 14.22 5.01 2.00 S2 8.17 5.40 0.12 S3 -7.27 4.33 1.64 -3.52 S4 -14.50 1.66 -11.13 S5 28.87 3.00 1.95 S6 -100.03 0.45 STO PL 1.54 S8 14766.71 3.00 1.52 S9 -22.88 0.07 S10 13.27 4.02 1.70 S11 -21.95 0.94 1.75 S12 9.11 8.45 1.50 S13 -28.69 0.10 S14 -20.58 2.00 1.66 -101.71 S15 -13.72 0.05 -8.70 S16 9.56 2.73 1.54 -14.44 S17 7.49 4.6 -7.27 S18 PL 0.80 1.52 S19 PL 1.25

[0062] The surface numbers in Table 1 are numbered according to the surface order of each lens, where "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and so on; "STO" represents the aperture of the lens; the radius of curvature represents the degree of curvature of the lens surface, a positive value represents that the surface bends towards the image plane side, and a negative value represents that the surface bends towards the object plane side, where "PL" represents that the surface is a plane 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 ability of the material between the current surface and the next surface to deflect light, and a space represents that the current position is air and the refractive index is 1; the K value represents the numerical value of the best-fitting conic coefficient of the aspherical surface.

[0063] The aspherical conic coefficient can be defined by the following aspherical formula, but is not limited to the following representation:

[0064]

[0065] Where z is the axial sagittal height of the aspherical surface in the Z direction; r is the height of the aspherical surface; c is the curvature of the fitting spherical surface, numerically the reciprocal of the radius of curvature; k is the fitting conic coefficient; A - F are the coefficients of the 4th, 6th, 8th, 10th, 12th, and 14th order terms of the aspherical polynomial.

[0066] Table 2 shows a design value of the aspherical coefficients in the fixed-focus lens:

[0067] A4 A6 A8 A10 A12 A14 S3 -5.40797E-04 2.00270E-05 -4.95875E-07 7.84382E-09 -5.33012E-11 0.00000E+00 S4 -1.82601E-04 9.87239E-06 -2.07542E-07 2.84138E-09 -1.57276E-11 0.00000E+00 S14 5.50674E-04 -8.90280E-06 4.61992E-08 1.73935E-10 -6.32110E-11 2.84448E-13 S15 4.38013E-04 -4.42015E-06 -1.97224E-07 8.63421E-11 2.51308E-11 -1.41158E-13 S16 -7.02572E-04 1.87462E-06 -9.15029E-08 -3.63303E-09 1.75534E-10 -1.08488E-12 S17 -6.44488E-04 8.91692E-06 -5.71557E-08 1.43485E-09 7.50325E-12 -5.36410E-14

[0068] Among them, Figure 2 is Figure 1 the axial aberration curve of the fixed-focus lens shown, Figure 3 is Figure 1 the field curvature curve of the fixed-focus lens shown, Figure 4 is Figure 1 the distortion curve of the fixed-focus lens shown, Figure 5 is Figure 1 the chromatic aberration curve of the fixed-focus lens shown. From Figure 2 , Figure 3 , Figure 4 and Figure 5 it can be seen that the fixed-focus lens provided in this embodiment has small axial aberration, small field curvature, small distortion, and small chromatic aberration, high resolution, and maintains good imaging quality at the full working distance.

[0069] Exemplarily, Figure 6 is the structural schematic diagram of another fixed-focus lens provided by an embodiment of the present invention. As shown in Figure 6 , in this embodiment, Figure 6The curvature radii, central thicknesses (i.e., the distances between the central points of adjacent mirror surfaces), refractive indices, and K values of the respective lenses along the optical axis from the object side to the image side in the shown lens satisfy the conditions listed in Table 3:

[0070] Table 3 shows another set of design values for the fixed-focus lens:

[0071] Surf Radius of Curvature (mm) Thickness (mm) Refractive Index K Value S1 14.20 5.29 2.00 S2 8.03 5.40 S3 -7.23 4.13 1.64 -3.85 S4 -15.69 1.49 -15.71 S5 29.22 3.00 1.95 S6 -123.08 0.45 STO PL 1.54 S8 -170.23 3.00 1.64 -100.00 S9 -21.83 0.07 -1.33 S10 13.43 3.93 1.70 S11 -23.14 0.94 1.85 S12 8.01 6.39 1.62 S13 -23.56 0.10 S14 -19.83 3.00 1.66 -44.96 S15 -17.52 0.05 -6.57 S16 11.75 3.14 1.54 -13.07 S17 9.84 4.34 -7.26 S18 PL 0.80 1.52 S19 PL 1.25

[0072] The surface numbers in Table 3 are numbered according to the surface order of each lens. Among them, "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and so on; "STO" represents the aperture stop of the lens; the curvature radius represents the degree of curvature of the lens surface. A positive value indicates that the surface bends towards the image side, and a negative value indicates that the surface bends towards the object side. Among them, "PL" represents that the surface is a plane and the curvature radius is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and a space represents that the current position is air and the refractive index is 1; the K value represents the numerical value of the best-fit conic coefficient of the aspherical surface.

[0073] The aspherical conic coefficient can be defined by the following aspherical formula, but is not limited to the following representation:

[0074]

[0075] Among them, z is the axial sagittal height of the aspherical surface in the Z direction; r is the height of the aspherical surface; c is the curvature of the fitted spherical surface, which is numerically the reciprocal of the curvature radius; k is the fitted conic coefficient; A - F are the coefficients of the 4th, 6th, 8th, 10th, 12th, and 14th order terms of the aspherical polynomial.

[0076] Table 4 shows a set of design values for the aspherical coefficients in the fixed-focus lens:

[0077] A4 A6 A8 A10 A12 A14 S3 -5.00481E-04 2.12385E-05 -4.89365E-07 7.50339E-09 -5.40334E-11 0.00000E+00 S4 -1.11307E-04 1.09901E-05 -2.02722E-07 2.89741E-09 -1.87565E-11 0.00000E+00 S8 1.39834E-05 3.68068E-07 1.54330E-09 -6.62541E-11 3.36102E-12 0.00000E+00 S9 1.59520E-05 4.20321E-08 2.66276E-09 8.30723E-11 -3.71457E-13 0.00000E+00 S14 4.81170E-04 -9.55049E-06 6.79065E-08 3.59778E-10 -6.88488E-11 6.89079E-13 S15 3.91433E-04 -6.38302E-06 -2.21475E-07 6.75593E-10 4.83386E-11 -2.42974E-13 S16 -8.21711E-04 -3.52816E-07 -7.29460E-08 -2.60970E-09 1.86427E-10 -1.54397E-12 S17 -7.74776E-04 1.31524E-05 6.01485E-10 8.15424E-10 8.62122E-12 2.40001E-13

[0078] Among them, Figure 7 is Figure 6 the axial aberration curve of the shown fixed-focus lens, Figure 8 is Figure 6 the field curvature curve of the shown fixed-focus lens, Figure 9 is Figure 6 the distortion curve of the shown fixed-focus lens, Figure 10 is Figure 6 the chromatic aberration curve of the shown fixed-focus lens. From Figure 7 , Figure 8 , Figure 9 and Figure 10It can be seen that the fixed-focus lens provided in this embodiment has small axial aberration, small field curvature, small distortion, small chromatic aberration, and high resolution, and maintains good imaging quality throughout the entire working distance.

[0079] Exemplarily, Figure 11 is a schematic structural diagram of another fixed-focus lens provided by an embodiment of the present invention. As Figure 11 shown, in this embodiment, Figure 11 for the optical lens shown, the radius of curvature, central thickness (i.e., the distance between the center points of adjacent mirror surfaces), refractive index, and K value of each lens along the optical axis from the object side to the image side satisfy the conditions listed in Table 5:

[0080] Table 5 is a set of design values for the fixed-focus lens:

[0081] Surf Radius of Curvature (mm) Thickness (mm) Refractive Index K Value S1 14.60 5.94 2.00 S2 7.98 5.40 S3 -7.79 4.14 1.64 -4.16 S4 -16.32 1.45 -16.91 S5 28.14 3.00 1.95 S6 -111.39 0.45 STO PL 1.54 S8 -45.74 3.00 1.64 -100.00 S9 -20.76 0.07 -9.04 S10 14.02 5.25 1.70 S11 -12.29 0.94 1.85 S12 7.34 4.10 1.62 S13 -36.74 0.10 S14 33.00 3.00 1.66 -24.71 S15 -29.08 0.05 8.36 S16 23.23 5.00 1.54 1.27 S17 10.01 3.00 -0.33 S18 PL 0.80 1.52 S19 PL 1.57

[0082] The surface numbers in Table 5 are numbered according to the surface order of each lens. Among them, "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and so on; "STO" represents the aperture stop of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value indicates that the surface bends towards the image side, and a negative value indicates that the surface bends towards the object side. Among them, "PL" represents that the surface is a plane 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 ability of the material between the current surface and the next surface to deflect light, and a space represents that the current position is air and the refractive index is 1; the K value represents the numerical value of the best-fit conic coefficient of the aspherical surface.

[0083] The aspherical conic coefficient can be defined by the following aspherical formula, but is not limited to the following representation:

[0084]

[0085]

[0086] Table 6 is a set of design values for the aspherical coefficients of the fixed-focus lens:

[0087] A4 A6 A8 A10 A12 A14 S3 -5.30555E-04 2.01159E-05 -4.91092E-07 8.68953E-09 -6.89591E-11 0.00000E+00 S4 -7.16557E-05 1.13725E-05 -1.97136E-07 2.66702E-09 1.56475E-12 0.00000E+00 S8 1.24022E-04 1.79952E-06 9.46488E-10 -3.70662E-10 1.49743E-11 0.00000E+00 S9 6.52120E-05 -3.47127E-07 1.40263E-08 3.39676E-10 4.62271E-12 0.00000E+00 S14 5.06858E-04 -1.03154E-05 6.14071E-08 5.46400E-10 -7.35402E-11 2.05302E-13 S15 1.72842E-04 -7.29999E-06 -1.65155E-07 1.98589E-09 5.26365E-11 -1.16269E-12 S16 -6.62192E-04 1.92590E-06 -7.82909E-08 -2.74654E-09 1.83175E-10 -1.54759E-12 S17 -4.41066E-04 1.45499E-05 -4.29123E-08 -2.50477E-09 1.55985E-10 -1.89024E-12

[0088] Figure 12 Among them, Figure 11 is Figure 13 the axial aberration curve of the fixed-focus lens shown, Figure 11 is Figure 14 the field curvature curve of the fixed-focus lens shown, Figure 11 ​​The distortion curve of the fixed-focus lens shown Figure 15 is Figure 11 the chromatic aberration curve of the fixed-focus lens shown. From Figure 12 , Figure 13 , Figure 14 and Figure 15 it can be seen that the fixed-focus lens provided in this embodiment has small axial aberration, small field curvature, small distortion and small chromatic aberration, high resolution, and maintains good imaging quality at the full working distance.

[0089] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A fixed-focus lens, characterized in that, Including: A first lens with a negative focal power, a second lens with a negative focal power, a third lens with a positive focal power, a diaphragm, a fourth lens with a positive focal power, a fifth lens with a positive focal power, a sixth lens with a negative focal power, a seventh lens with a positive focal power, an eighth lens with a positive or negative focal power, and a ninth lens with a positive or negative focal power, which are arranged in sequence from the object side to the image side along the optical axis; The fifth lens, the sixth lens, and the seventh lens are three-piece cemented lenses; the second lens is an aspherical lens; The object side surface of the first lens is convex, and the image side surface of the first lens is concave; the object side surface of the second lens is concave, and the image side surface of the second lens is convex; the object side surface of the third lens is convex, and the image side surface of the third lens is convex or concave; the object side surface of the fourth lens is convex or concave, and the image side surface of the fourth lens is concave or convex; the object side surface of the fifth lens is convex, and the image side surface of the fifth lens is concave; the object side surface of the sixth lens is concave, and the image side surface of the sixth lens is concave; the object side surface of the seventh lens is convex, and the image side surface of the seventh lens is convex; the object side surface of the eighth lens is convex or concave, and the image side surface of the eighth lens is convex or concave; the object side surface of the ninth lens is convex or concave, and the image side surface of the ninth lens is convex or concave; The first lens, the third lens, the fifth lens, the sixth lens, and the seventh lens are all glass spherical lenses; The second lens, the eighth lens, and the ninth lens are all plastic aspherical lenses; The fourth lens is a glass spherical lens or a plastic aspherical lens.

2. The fixed-focus lens according to claim 1, wherein The focal power of the first lens and the focal power of the fixed-focus lens satisfy 0.5 ≤ |φ / φ1| ≤ 5; Wherein, φ is the focal power of the fixed-focus lens, and φ1 is the focal power of the first lens.

3. The fixed-focus lens according to claim 1, wherein The focal power of the first lens and the thickness of the first lens satisfy -1 ≤ D1*φ1; Wherein, φ1 is the focal power of the first lens, and D1 is the thickness of the first lens. And the refractive index Nd1 of the first lens satisfies Nd1 > 1.

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4. The fixed-focus lens according to claim 1, wherein The focal power of the second lens and the focal power of the fixed-focus lens satisfy 0.5 ≤ |φ / φ2|; Wherein, φ is the focal power of the fixed-focus lens, and φ2 is the focal power of the second lens.

5. The fixed-focus lens according to claim 1, wherein The refractive index Nd2 of the second lens satisfies 1.5 ≤ Nd2 ≤ 1.

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6. The fixed-focus lens according to claim 1, wherein, The third lens is a glass spherical lens or a plastic aspherical lens, and the fourth lens is a glass spherical lens or a plastic aspherical lens; And the focal power of the third lens and the focal power of the fourth lens satisfy: 0.1 ≤ |φ4 / φ3| ≤ 10; Wherein, φ3 is the focal power of the third lens, and φ4 is the focal power of the fourth lens.

7. The fixed-focus lens according to claim 1, characterized in that, The Abbe numbers of the fifth lens, the sixth lens, and the seventh lens respectively satisfy: Vd5 - Vd6 > 20, Vd7 - Vd6 > 20; Wherein, Vd5 is the Abbe number of the fifth lens, Vd6 is the Abbe number of the sixth lens, and Vd7 is the Abbe number of the seventh lens.

8. The fixed-focus lens according to claim 1, characterized in that, The thickness of the eighth lens, the thickness of the ninth lens, and the optical power of the fixed-focus lens satisfy 0.2 < |(D8 + D9) * φ| < 2; where D8 is the thickness of the eighth lens, D9 is the thickness of the ninth lens, and φ is the optical power of the fixed-focus lens.

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