Athermalization wide-spectrum low-distortion wide-angle lens

Abstract

The invention discloses an athermalization wide-spectrum low-distortion wide-angle lens, and belongs to the technical field of imaging lenses. Comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, an aperture diaphragm, a seventh lens, an eighth lens, a ninth lens, a tenth lens and an eleventh lens which are sequentially arranged from an object side to an image side. Wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens form a front lens group, and the seventh lens, the eighth lens, the ninth lens, the tenth lens and the eleventh lens form a rear lens group. The aperture diaphragm is located on the front focal plane of the rear lens group, all the lenses are not glued, and the second lens and the fifth lens adopt single-face aspheric surfaces. Through reasonable distribution of the focal power of the light from the first lens to the eleventh lens, the design requirements of large view field, high resolution, wide spectrum, clear imaging in a wide temperature range and low distortion are met, and the application requirements of different fields can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, and in particular to an athermal, wide-band, low-distortion wide-angle lens. Background Art

[0002] Wide-angle lenses have the characteristics of short focal length and large field of view, which realize functions that ordinary imaging lenses cannot achieve. They are widely used in aviation, aerospace and other fields. Wide-angle lenses are large aberration systems. In order to correct aberrations, wide-angle lenses often use high refractive index materials or small curvature radius structures. This design is often sensitive to temperature. When the external ambient temperature changes, the position of the image plane will change, resulting in a decrease in imaging clarity. In addition, due to the sharp increase in aberrations caused by the increase in field of view, the difficulty of distortion correction is particularly great. Usually, aspheric balance distortion and astigmatism are introduced at a position far away from the field of view aperture.

[0003] For example, a wide-angle lens disclosed in the Chinese patent application number CN111812826A includes the first lens to the sixth lens arranged in sequence from the object side to the image side, wherein the first lens and the fourth lens are both glass lenses, and the remaining lenses are all plastic aspherical surfaces, which can ensure the imaging requirements of stable optical properties at low temperatures of -40°C and high temperatures of 85°C. However, the edge field of view distortion is about 100%, and the distortion value is large, which greatly increases the difficulty of geometric calibration and correction. Moreover, the working band of traditional wide-angle lenses is generally visible light, and the spectral range is narrow, which is difficult to apply to the detection needs of complex feature targets. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide an athermalized wide-band low-distortion wide-angle lens that can achieve large field of view, high resolution, wide spectrum, low distortion, and clear imaging design requirements under a wide temperature range.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] An athermal, wide-band, low-distortion wide-angle lens, which includes a front lens group, a rear lens group, and an aperture stop in sequence from the object side to the imaging surface along the optical axis, wherein the front lens group includes:

[0007] The first lens has a negative optical power, the object side surface of which is convex, the image side surface of which is concave, and the absolute value of the optical power is 0.003≤≤0.01;

[0008] The second lens with negative optical power has a convex object side surface and a concave image side surface, and the absolute value of the optical power is 0.01≤≤0.03;

[0009] The third lens with negative optical power has a flat object side surface and a concave image side surface, and the absolute value of the optical power is 0.005≤≤0.02;

[0010] The fourth lens element has negative power, both the object side surface and the image side surface are concave, and the absolute value of the power is 0.01≤≤0.03;

[0011] A fifth lens having positive refractive power, whose object side surface is concave, whose image side surface is convex, and whose absolute value of refractive power is 0.005≤≤0.015;

[0012] The sixth lens element has positive refractive power, both the object side surface and the image side surface are convex, and the absolute value of the refractive power is 0.005≤≤0.015;

[0013] The rear lens group comprises:

[0014] The seventh lens element with negative refractive power has a concave object side surface and a convex image side surface, and an absolute value of the refractive power of 0.005≤≤0.01;

[0015] The eighth lens with negative optical power has a convex surface on both the object side and the image side, and the absolute value of the optical power is 0.04≤≤0.08;

[0016] The ninth lens with negative optical power has a concave surface on both the object side and the image side, and an absolute value of the optical power of 0.06≤≤0.10;

[0017] The tenth lens with negative optical power has a convex surface on both the object side and the image side, and the absolute value of the optical power is 0.01≤≤0.04;

[0018] The eleventh lens with negative refractive power has a convex surface on both the object side and the image side, and the absolute value of the refractive power is 0.02≤≤0.05;

[0019] The aperture stop is located between the sixth lens and the seventh lens, and the aperture stop is close to the seventh lens;

[0020] The first to eleventh lenses are separated from each other.

[0021] As a further solution of the present invention: the refractive index range of the first lens is 1.40≤n≤1.50, and the dispersion range is 60≤ν≤80; the refractive index range of the second lens is 1.60≤n≤1.70, and the dispersion range is 50≤ν≤65; the refractive index range of the third lens is 1.60≤n≤1.70, and the dispersion range is 50≤ν≤65; the refractive index range of the fourth lens is 1.75≤n≤1.85, and the dispersion range is 30≤ν≤40; the refractive index range of the fifth lens is 1.70≤n≤1.80, and the dispersion range is 45≤ν≤55; the refractive index range of the sixth lens is 1.70≤n≤1.80, and the dispersion range is 45≤ν≤55.

[0022] As a further solution of the present invention: the refractive index range of the seventh lens is 1.75≤n≤1.85, and the dispersion range is 30≤ν≤40; the refractive index range of the eighth lens is 1.40≤n≤1.50, and the dispersion range is 85≤ν≤95; the refractive index range of the ninth lens is 1.80≤n≤1.85, and the dispersion range is 35≤ν≤50; the refractive index range of the tenth lens is 1.40≤n≤1.50, and the dispersion range is 85≤ν≤95; the refractive index range of the eleventh lens is 1.60≤n≤1.70, and the dispersion range is 55≤ν≤65.

[0023] As a further solution of the present invention: the effective focal length f of the wide-angle lens and the entrance pupil diameter EPD of the wide-angle lens satisfy: 4≤f / EPD.

[0024] As a further solution of the present invention: the back focus BFL of the wide-angle lens and the total optical length TTL of the wide-angle lens satisfy: 0.07≤BFL / TTL≤0.10.

[0025] As a further solution of the present invention: the relative distortion DI ST of the wide-angle lens satisfies: DI ST≤2%.

[0026] As a further solution of the present invention: the image-side surface of the second lens and the image-side surface of the fifth lens are both aspherical surfaces.

[0027] As a further solution of the present invention: the aspheric surface shapes of the second lens and the fifth lens satisfy the equation:

[0028]

[0029] Among them, z is the aspheric surface sag, c is the aspheric surface vertex curvature, y is the aperture, k is the cone coefficient, A4 is the 4th aspheric surface coefficient, A6 is the 6th aspheric surface coefficient, A8 is the 8th aspheric surface coefficient, A 10 is the 10th-order aspheric coefficient.

[0030] As a further solution of the present invention: the aspheric surface tolerances of the second lens and the fifth lens are both less than 2 um.

[0031] Beneficial effects of the present invention:

[0032] (1) The present invention achieves the design requirements of large field of view, high resolution, wide spectrum, clear imaging in a wide temperature range, and low distortion through the reasonable distribution of the optical power of the first lens to the eleventh lens, and can meet the application requirements of different fields;

[0033] (2) The second lens and the fifth lens in the present invention both use a single-sided aspheric surface, which achieves the correction of distortion and other aberrations. Compared with the double-sided aspheric surface in the prior art, the processing cost is reduced, and the surface shape tolerance of the aspheric surface is less than 2um, which is relatively loose. Therefore, the aspheric surface in the present invention meets the current aspheric surface processing technology and has strong engineering feasibility;

[0034] (3) There is no cemented lens in the optical path of the present invention, thus avoiding the risk of the cementing layer falling off;

[0035] (4) The present invention adopts a variety of glass materials for athermal material matching, taking into account the fact that the space environment is relatively harsh compared to the ground environment, and can achieve passive athermalization and clear imaging in a wide temperature range; by matching different materials, the lens can ensure high imaging quality in a wide temperature range of -40°C to 60°C;

[0036] (5) The present invention uses two pieces of low-dispersion and low-refractive-index materials to correct the lateral chromatic aberration of the lens and meet the design requirements of a wide spectral band. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be further described below in conjunction with the accompanying drawings.

[0038] Figure 1 It is a schematic diagram of the structure of an athermal wide-band low-distortion wide-angle lens of the present invention;

[0039] Figure 2 It is a schematic diagram of the structure of the rear lens group of the present invention;

[0040] Figure 3 is a modulation transfer function (MTF) curve of the first embodiment of the present invention at -40°C;

[0041] Figure 4 is a modulation transfer function (MTF) curve of the first embodiment of the present invention at 0°C;

[0042] Figure 5 is a modulation transfer function (MTF) curve of the first embodiment of the present invention at 20°C;

[0043] Figure 6 is a modulation transfer function (MTF) curve of the first embodiment of the present invention at 60° C.;

[0044] Figure 7 is the relative distortion curve of the first embodiment of the present invention;

[0045] Figure 8 is a lateral chromatic aberration curve of the first embodiment of the present invention;

[0046] Fig. 9is a modulation transfer function (MTF) curve of the second embodiment of the present invention at -40°C;

[0047] Fig.10 is a modulation transfer function (MTF) curve of the second embodiment of the present invention at 0°C;

[0048] Fig.11 is a modulation transfer function (MTF) curve of the second embodiment of the present invention at 20°C;

[0049] Fig.12 is a modulation transfer function (MTF) curve of the second embodiment of the present invention at 60°C;

[0050] Fig.13 is the relative distortion curve of the second embodiment of the present invention;

[0051] Fig.14 is a lateral chromatic aberration curve of the second embodiment of the present invention.

[0052] In the figure: 1, front lens group; 11, first lens; 12, second lens; 13, third lens; 14, fourth lens; 15, fifth lens; 16, sixth lens; 2, rear lens group; 21, seventh lens; 22, eighth lens; 23, ninth lens; 24, tenth lens; 25, eleventh lens; 3, aperture stop. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] See also Figure 1-14 As shown, the present invention provides an athermal wide-band low-distortion wide-angle lens, which includes 11 lenses, 2 of which are aspherical and the rest are spherical, and adopts an anti-telephoto structure with a reasonable distribution of negative and positive optical powers.

[0055] Specifically, it includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a sixth lens 16, an aperture stop 3, a seventh lens 21, an eighth lens 22, a ninth lens 23, a tenth lens 24, and an eleventh lens 25, which are coaxially arranged in sequence along the incident direction. Among them, the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, and the sixth lens 16 constitute a front lens group 1, the seventh lens 21, the eighth lens 22, the ninth lens 23, the tenth lens 24, and the eleventh lens 25 constitute a rear lens group 2, and the aperture stop 3 is located near the front focal plane of the rear lens group 2.

[0056] The first lens 11 is a meniscus lens with negative optical power, whose object side surface is convex and image side surface is concave, and the absolute value of the optical power is 0.003≤≤0.01. The refractive index range of the first lens 11 is 1.40≤n≤1.50, and the dispersion range is 60≤ν≤80.

[0057] The second lens 12 is a meniscus lens with negative optical power, whose object side surface is convex and image side surface is concave, and the absolute value of the optical power is 0.01≤≤0.03. The refractive index range of the second lens 12 is 1.60≤n≤1.70, and the dispersion range is 50≤ν≤65.

[0058] The third lens 13 is a plano-concave lens with negative power, whose object side surface is a plane and image side surface is a concave surface. The absolute value of the power is 0.005≤≤0.02. The refractive index range of the third lens 13 is 1.60≤n≤1.70, and the dispersion range is 50≤ν≤65.

[0059] The fourth lens 14 is a double concave lens with negative optical power, whose object side surface and image side surface are both concave, 0.01≤optical power absolute value≤0.03, the refractive index range of the fourth lens 14 is 1.75≤n≤1.85, and the dispersion range is 30≤ν≤40.

[0060] The fifth lens 15 is a meniscus lens with positive power, with a concave object side surface and a convex image side surface. The absolute value of the power is 0.005≤≤0.015. The refractive index range of the fifth lens 15 is 1.70≤n≤1.80, and the dispersion range is 45≤ν≤55.

[0061] The sixth lens 16 is a biconvex lens with positive power, whose object side surface and image side surface are both convex, and the absolute value of the optical power is 0.005≤≤0.015. The refractive index range of the sixth lens 16 is 1.70≤n≤1.80, and the dispersion range is 45≤ν≤55.

[0062] The seventh lens 21 is a meniscus lens with negative power, with a concave object side surface and a convex image side surface. The absolute value of the power is 0.005≤≤0.01, the refractive index range of the seventh lens 21 is 1.75≤n≤1.85, and the dispersion range is 30≤ν≤40.

[0063] The eighth lens 22 is a double convex lens with negative optical power, whose object side surface and image side surface are both convex, 0.04≤optical power absolute value≤0.08, the refractive index range of the eighth lens 22 is 1.40≤n≤1.50, and the dispersion range is 85≤ν≤95.

[0064] The ninth lens 23 is a double concave lens with negative optical power, wherein both the object side surface and the image side surface are concave, the absolute value of the optical power is 0.06≤≤0.10, the refractive index range of the ninth lens 23 is 1.80≤n≤1.85, and the dispersion range is 35≤ν≤50.

[0065] The tenth lens 24 is a double convex lens with negative optical power, whose object side surface and image side surface are both convex, 0.01≤optical power absolute value≤0.04, the refractive index range of the tenth lens 24 is 1.40≤n≤1.50, and the dispersion range is 85≤ν≤95.

[0066] The eleventh lens 25 is a double convex lens with negative optical power, wherein both the object side surface and the image side surface are convex, and the absolute value of the optical power is 0.02≤≤0.05. The refractive index range of the eleventh lens 25 is 1.60≤n≤1.70, and the dispersion range is 55≤ν≤65.

[0067] It should be noted that the effective focal length f and entrance pupil diameter EPD of the athermal wide-spectrum low-distortion wide-angle lens provided by the present invention satisfy: 4≤f / EPD. The back focus BFL and total optical length TTL of the athermal wide-spectrum low-distortion wide-angle lens provided by the present invention satisfy: 0.07≤BFL / TTL≤0.10. The relative distortion DI ST of the athermal wide-spectrum low-distortion wide-angle lens provided by the present invention satisfies: DI ST≤2%. .

[0068] It is worth noting that the image side surface of the second lens 12 and the image side surface of the fifth lens 15 are both aspherical surfaces, and the aspherical surface shapes satisfy the equation:

[0069]

[0070] Among them, z is the aspheric surface sag, c is the aspheric surface vertex curvature, y is the aperture, k is the cone coefficient, A4 is the 4th aspheric surface coefficient, A6 is the 6th aspheric surface coefficient, A8 is the 8th aspheric surface coefficient, A 10 is the 10th-order aspheric coefficient.

[0071] Embodiment 1

[0072] In this embodiment, the absolute value of the optical power of the first lens 11 is preferably 0.0075. In this embodiment, the first lens 11 is preferably made of SILIC A glass material, with a refractive index of 1.46 and a dispersion of 67.82.

[0073] In this embodiment, the absolute value of the optical power of the second lens 12 is preferably 0.023. In this embodiment, the second lens 12 is preferably made of N-SK2 glass material, with a refractive index of 1.61 and a dispersion of 56.65.

[0074] In this embodiment, the third lens 13 preferably has an absolute value of optical power of 0.01. In this embodiment, the third lens 13 is preferably made of N-SK2 glass material, with a refractive index of 1.61 and a dispersion of 56.65.

[0075] In this embodiment, the fourth lens 14 preferably has an absolute value of optical power of 0.015. In this embodiment, the fourth lens 14 is preferably made of H-ZLAF66 glass material, with a refractive index of 1.80 and a dispersion of 34.97.

[0076] In this embodiment, the fifth lens 15 preferably has an absolute value of optical power of 0.009. In this embodiment, the fifth lens 15 is preferably made of H-LAF53 glass material, with a refractive index of 1.74 and a dispersion of 49.24.

[0077] In this embodiment, the sixth lens 16 preferably has an absolute value of optical power of 0.009. In this embodiment, the sixth lens 16 is preferably made of H-LAF53 glass material, with a refractive index of 1.74 and a dispersion of 49.24.

[0078] In this embodiment, the seventh lens 21 preferably has an absolute value of optical power of 0.007. In this embodiment, the seventh lens 21 is preferably made of H-ZLAF66 glass material, with a refractive index of 1.80 and a dispersion of 34.97.

[0079] In this embodiment, the eighth lens 22 preferably has an absolute value of optical power of 0.058. In this embodiment, the eighth lens 22 is preferably made of N-FK58 glass material, with a refractive index of 1.46 and a dispersion of 90.90.

[0080] In this embodiment, the ninth lens 23 preferably has an absolute value of optical power of 0.085. In this embodiment, the ninth lens 23 is preferably made of N-LASF41 glass material, with a refractive index of 1.84 and a dispersion of 43.13.

[0081] In this embodiment, the tenth lens 24 preferably has an absolute value of optical power of 0.023. In this embodiment, the tenth lens 24 is preferably made of N-FK58 glass material, with a refractive index of 1.46 and a dispersion of 90.90.

[0082] In this embodiment, the eleventh lens 25 preferably has an absolute value of optical power of 0.032. In this embodiment, the eleventh lens 25 is preferably made of N-SK2 glass material, with a refractive index of 1.61 and a dispersion of 56.65.

[0083] In this embodiment, the two aspheric coefficients are as follows:

[0084] element k A4 A6 A8 A10 Second lens -1.00 0 0 0 0 Fifth lens -0.92 0 0 0 0

[0085] The athermal difference wide spectrum low distortion wide angle lens provided in this embodiment has an effective focal length of f=7mm, a full field of view angle of 122°, an operating band of 440-910nm, an aperture number, i.e., a ratio of the effective focal length f to the entrance pupil diameter EPD of 4.5, a total optical length of 350mm, a clear aperture of the first lens (11) of 205mm, and an incident angle CRA of the chief rays of all fields of view on the image plane of no more than 2°, thereby achieving a large field of view and image telecentricity, and an edge field of view image plane illumination of better than 85%. The imaging lens of this embodiment can meet the design requirements of large field of view, athermal difference, low distortion, high resolution, etc.

[0086] like Figure 3-Figure 6 The figure shows the modulation transfer function (MTF) curves of the athermal wide spectrum low distortion wide angle lens provided in this embodiment at -40°C, 0°C, 20°C and 60°C respectively. Figure 3-Figure 6 The horizontal axis represents the spatial frequency in line pairs per millimeter (lp / mm), and the vertical axis represents the MTF value. Figure 3-Figure 6 It is shown in the figure that at a spatial frequency of 25l p / mm, the MTF of all fields of view under different temperatures is greater than 0.60. Compared with the standard temperature of 20°C, the decrease of MTF under different temperatures does not exceed 0.1, indicating that the lens can form a clear image on the entire image plane and has good athermal performance.

[0087] like Figure 7 The figure shows the distortion curve of the athermal wide-spectrum low-distortion wide-angle lens provided in this embodiment, where the abscissa represents relative distortion and the ordinate represents field of view. Figure 7 It is shown in the figure that the relative distortion DI ST of all fields of view of the athermal, wide spectrum, low distortion wide-angle lens provided by this embodiment is less than 2%.

[0088] like Figure 8 The figure shows the lateral chromatic aberration curve of the athermal wide-spectrum low-distortion wide-angle lens provided in this embodiment. In the figure, the abscissa represents the lateral chromatic aberration, and the ordinate represents the normalized field of view. Figure 8 It is shown in the figure that the lateral chromatic aberration of the athermal, wide-spectrum, low-distortion wide-angle lens provided in this embodiment is less than 6 um, and the lateral chromatic aberration is well corrected.

[0089] Embodiment 2

[0090] In this embodiment, the absolute value of the optical power of the first lens 11 is preferably 0.0056. In this embodiment, the first lens 11 is preferably made of SILIC A glass material, with a refractive index of 1.46 and a dispersion of 67.82.

[0091] In this embodiment, the absolute value of the optical power of the second lens 12 is preferably 0.025. In this embodiment, the second lens 12 is preferably made of N-SK4 glass material, with a refractive index of 1.61 and a dispersion of 58.63.

[0092] In this embodiment, the third lens 13 preferably has an absolute value of optical power of 0.014. In this embodiment, the third lens 13 is preferably made of N-SK4 glass material, with a refractive index of 1.61 and a dispersion of 58.63.

[0093] In this embodiment, the fourth lens 14 preferably has an absolute value of optical power of 0.021. In this embodiment, the fourth lens 14 is preferably made of H-ZLAF53B glass material, with a refractive index of 1.84 and a dispersion of 37.23.

[0094] In this embodiment, the fifth lens 15 preferably has an absolute value of optical power of 0.013. In this embodiment, the fifth lens 15 is preferably made of H-LAF53 glass material, with a refractive index of 1.74 and a dispersion of 49.24.

[0095] In this embodiment, the sixth lens 16 preferably has an absolute value of optical power of 0.013. In this embodiment, the sixth lens 16 is preferably made of H-LAF53 glass material, with a refractive index of 1.74 and a dispersion of 49.24.

[0096] In this embodiment, the seventh lens 21 preferably has an absolute value of optical power of 0.009. In this embodiment, the seventh lens 21 is preferably made of H-ZLAF53B glass material, with a refractive index of 1.84 and a dispersion of 37.23.

[0097] In this embodiment, the eighth lens 22 preferably has an absolute value of optical power of 0.078. In this embodiment, the eighth lens 22 is preferably made of CAF2 glass material, with a refractive index of 1.44 and a dispersion of 95.00.

[0098] In this embodiment, the ninth lens 23 preferably has an absolute value of optical power of 0.098. In this embodiment, the ninth lens 23 is preferably made of N-LASF41 glass material, with a refractive index of 1.84 and a dispersion of 43.13.

[0099] In this embodiment, the tenth lens 24 preferably has an absolute value of optical power of 0.032. In this embodiment, the tenth lens 24 is preferably made of CAF2 glass material, with a refractive index of 1.44 and a dispersion of 95.00.

[0100] In this embodiment, the eleventh lens 25 preferably has an absolute value of optical power of 0.045. In this embodiment, the eleventh lens 25 is preferably made of N-SK4 glass material, with a refractive index of 1.61 and a dispersion of 58.63.

[0101] In this embodiment, the two aspheric coefficients are as follows:

[0102] element k A4 A6 A8 A10 Second lens -1.00 0 0 0 0 Fifth lens -0.92 0 0 0 0

[0103] The effective focal length of the athermal difference wide spectrum low distortion wide-angle lens of the present embodiment is f=5mm, the full field of view angle is 118°, the working band is 400-865nm, the aperture number, that is, the ratio of the effective focal length f to the entrance pupil diameter ENPD is 4.2, the total optical length is 264mm, the ratio of the back focus BFL to the total optical length TTL of the imaging lens is 0.076, and the incident angle CRA of the main light of all fields of view on the image plane is not greater than 1°, achieving a large field of view and image telecentricity, and the edge field of view image plane illumination is better than 90%. The lens of the present embodiment can meet the design requirements of large field of view, athermal difference, low distortion, high resolution, etc.

[0104] like Figure 9-12 The figure shows the modulation transfer function (MTF) curves of the athermal wide spectrum low distortion wide angle lens of this embodiment at -40°C, 0°C, 20°C and 60°C. The horizontal axis in the figure represents the spatial frequency in line pairs per millimeter (lp / mm), and the vertical axis represents the MTF value. The figure shows that at a spatial frequency of 35l p / mm, the MTF of all fields of view under different temperatures is greater than 0.60. Compared with the standard temperature of 20°C, the decrease of MTF under different temperatures does not exceed 0.1, indicating that the lens can form a clear image on the entire image plane and has good athermal performance.

[0105] like Fig.13 The distortion curve of the athermal wide-spectrum low-distortion wide-angle lens of this embodiment is shown, with the horizontal axis representing relative distortion and the vertical axis representing field of view. The figure shows that the relative distortion DI ST of all fields of view is less than 2%.

[0106] like Fig.14 The figure shows the lateral chromatic aberration curve of the athermal wide-spectrum low-distortion wide-angle lens provided in this embodiment. In the figure, the abscissa represents the lateral chromatic aberration, and the ordinate represents the normalized field of view. Fig.14 It is shown in the figure that the lateral chromatic aberration of the athermal, wide-spectrum, low-distortion wide-angle lens provided in this embodiment is less than 5um, and the lateral chromatic aberration is well corrected.

[0107] In summary, the present invention provides an athermal, wide-band, low-distortion wide-angle lens, which achieves the design requirements of large field of view, high resolution, wide spectrum, clear imaging in a wide temperature range, and low distortion, and can meet the application requirements of different fields.

[0108] The above is a detailed description of the preferred embodiments of the present invention, which cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. An athermal wide-band low-distortion wide-angle lens, characterized by: The optical system includes a front lens group (1), a rear lens group (2) and an aperture stop (3) in sequence from the object side to the imaging surface along the optical axis. The front lens group (1) includes: A first lens (11) with negative optical power, whose object side surface is convex, image side surface is concave, and the absolute value of the optical power is 0.003≤≤0.01; A second lens (12) with negative optical power, whose object side surface is convex, image side surface is concave, and the absolute value of the optical power is 0.01≤≤0.03; A third lens (13) with negative power, whose object side surface is a flat surface, image side surface is a concave surface, and the absolute value of the power is 0.005≤≤0.02; A fourth lens (14) with negative refractive power, whose object side surface and image side surface are both concave, and the absolute value of the refractive power is 0.01≤≤0.03; a fifth lens (15) having positive refractive power, whose object side surface is concave, whose image side surface is convex, and whose absolute value of refractive power is 0.005≤≤0.015; A sixth lens (16) with positive refractive power, whose object side surface and image side surface are both convex, and the absolute value of the refractive power is 0.005≤≤0.015; The rear lens group (2) comprises: A seventh lens (21) with negative refractive power, whose object side surface is concave, image side surface is convex, and the absolute value of the refractive power is 0.005≤≤0.01; An eighth lens (22) with negative optical power, whose object side surface and image side surface are both convex, and the absolute value of the optical power is 0.04≤≤0.08; A ninth lens (23) having negative refractive power, wherein both the object side surface and the image side surface are concave, and the absolute value of the refractive power is 0.06≤≤0.10; A tenth lens (24) with negative optical power, whose object side surface and image side surface are both convex, and the absolute value of the optical power is 0.01≤≤0.04; An eleventh lens (25) with negative refractive power, whose object side surface and image side surface are both convex, and the absolute value of the refractive power is 0.02≤≤0.05; The aperture stop (3) is located between the sixth lens (16) and the seventh lens (21), and the aperture stop (3) is close to the seventh lens (21); The first lens (11) to the eleventh lens (25) are separated from each other.

2. The athermal wide-band low-distortion wide-angle lens according to claim 1, characterized in that: The refractive index range of the first lens (11) is 1.40≤n≤1.50, and the dispersion range is 60≤ν≤80; the refractive index range of the second lens (12) is 1.60≤n≤1.70, and the dispersion range is 50≤ν≤65; the refractive index range of the third lens (13) is 1.60≤n≤1.70, and the dispersion range is 50≤ν≤65; the refractive index range of the fourth lens (14) is 1.75≤n≤1.85, and the dispersion range is 30≤ν≤40; the refractive index range of the fifth lens (15) is 1.70≤n≤1.80, and the dispersion range is 45≤ν≤55; the refractive index range of the sixth lens (16) is 1.70≤n≤1.80, and the dispersion range is 45≤ν≤55.

3. The athermal wide-band low-distortion wide-angle lens according to claim 2, characterized in that: The refractive index range of the seventh lens (21) is 1.75≤n≤1.85, and the dispersion range is 30≤ν≤40; the refractive index range of the eighth lens (22) is 1.40≤n≤1.50, and the dispersion range is 85≤ν≤95; the refractive index range of the ninth lens (23) is 1.80≤n≤1.85, and the dispersion range is 35≤ν≤50; the refractive index range of the tenth lens (24) is 1.40≤n≤1.50, and the dispersion range is 85≤ν≤95; the refractive index range of the eleventh lens (25) is 1.60≤n≤1.70, and the dispersion range is 55≤ν≤65.

4. The athermal wide-band low-distortion wide-angle lens according to claim 1, characterized in that: The effective focal length f of the wide-angle lens and the entrance pupil diameter EPD of the wide-angle lens satisfy: 4≤f / EPD.

5. The athermal wide-band low-distortion wide-angle lens according to claim 1, characterized in that: The back focus BFL of the wide-angle lens and the total optical length TTL of the wide-angle lens satisfy: 0.07≤BFL / TTL≤0.

10.

6. The athermal wide-band low-distortion wide-angle lens according to claim 1, characterized in that: The relative distortion DI ST of the wide-angle lens satisfies: DI ST≤2%.

7. The athermal wide-band low-distortion wide-angle lens according to claim 1, characterized in that: The image-side surface of the second lens (12) and the image-side surface of the fifth lens (15) are both aspherical surfaces.

8. The athermal wide-band low-distortion wide-angle lens according to claim 7, characterized in that: The aspheric surface shapes of the second lens (12) and the fifth lens (15) satisfy the equation: Among them, z is the aspheric surface sag, c is the aspheric surface vertex curvature, y is the aperture, k is the cone coefficient, A4 is the 4th aspheric surface coefficient, A6 is the 6th aspheric surface coefficient, A8 is the 8th aspheric surface coefficient, A 10 is the 10th-order aspheric coefficient.

9. The athermal wide-band low-distortion wide-angle lens according to claim 8, characterized in that: The aspheric surface tolerances of the second lens (12) and the fifth lens (15) are both less than 2 um.

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