Athermal wide-angle lens with low distortion and wide spectrum

Abstract

The application discloses a kind of heat-difference wide spectrum low-distortion wide-angle lenses, belong to imaging lens technical field.It includes from object side to image side sequentially arranged first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, aperture diaphragm, seventh lens, eighth lens, ninth lens, tenth lens, eleventh lens.First lens, second lens, third lens, fourth lens, fifth lens, sixth lens constitute front lens group, seventh lens, eighth lens, ninth lens, tenth lens, eleventh lens constitute rear lens group.Aperture diaphragm is located at the front focal plane of rear lens group, there is no cementation between all lenses, second lens and fifth lens adopt single face aspheric surface.The application realizes the design requirement of big field of view, high resolution, wide spectrum, can clearly image in wide temperature range, low distortion by the reasonable distribution of the light power of first lens to eleventh lens, can satisfy the application demand of different fields.

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, with their short focal length and wide field of view, enable functions that ordinary imaging lenses cannot achieve, and are widely used in fields such as aviation and aerospace. Wide-angle lenses are systems with large aberrations. To correct for these aberrations, they often use high-refractive-index materials or structures with small radii of curvature. This design is often sensitive to temperature. When the ambient temperature changes, the position of the image plane will shift, resulting in a decrease in image clarity. Furthermore, the increase in field of view leads to a sharp increase in aberrations, especially distortion correction, which is extremely difficult. Aspherical surfaces are often introduced at locations far from the field stop to balance distortion and astigmatism.

[0003] For example, Chinese patent application number CN111812826A discloses a wide-angle lens comprising first through sixth lenses arranged sequentially from object to image. The first and fourth lenses are glass, while the remaining lenses are plastic aspherical surfaces. This lens maintains stable optical properties at temperatures ranging from -40°C to 85°C. However, the peripheral field of view distortion is approximately 100%, a significant amount that significantly increases the difficulty of geometric calibration and correction. Furthermore, conventional wide-angle lenses typically operate in the visible light band, which has a narrow spectral range and is difficult to apply to the detection of complex 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-spectrum, low-distortion wide-angle lens that can achieve the design requirements of large field of view, high resolution, wide spectrum, low distortion, and clear imaging over 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 comprises, in order from the object side to the imaging plane along the optical axis, a front lens group, a rear lens group, and an aperture stop, wherein the front lens group comprises:

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

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

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

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

[0011] The fifth lens element has positive refractive power, its object-side surface is concave, its image-side surface is convex, and its absolute value of refractive power is 0.005 ≤ ≤ 0.015;

[0012] a sixth lens element having positive refractive power, both the object-side surface and the image-side surface of the lens element being convex, and an absolute value of the refractive power being 0.005 ≤ ≤ 0.015;

[0013] The rear lens group includes:

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

[0015] An eighth lens element having negative optical power, both the object-side surface and the image-side surface of the lens element having a convex surface, and an absolute value of the optical power of the lens element being 0.04 ≤ ≤ 0.08;

[0016] The ninth lens element has negative optical power, both the object side surface and the image side surface are concave, and the absolute value of the optical power is 0.06≤≤0.10;

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

[0018] An eleventh lens having negative refractive power, both the object-side surface and the image-side surface of the lens are convex, 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 element is 1.75≤n≤1.85, and the dispersion range is 30≤ν≤40; the refractive index range of the eighth lens element is 1.40≤n≤1.50, and the dispersion range is 85≤ν≤95; the refractive index range of the ninth lens element is 1.80≤n≤1.85, and the dispersion range is 35≤ν≤50; the refractive index range of the tenth lens element is 1.40≤n≤1.50, and the dispersion range is 85≤ν≤95; the refractive index range of the eleventh lens element 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 profiles of the second lens and the fifth lens satisfy the equation:

[0028]

[0029] Among them, z is the aspheric surface height, 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 μm.

[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 application are single-sided aspheric surfaces, the correction of aberrations such as distortion is realized, compared with the double-sided aspheric surfaces in the prior art, the processing cost is reduced, and the surface tolerance of the aspheric surface is less than 2um, the surface tolerance is relatively loose. Therefore, the aspheric surface in the application meets the current aspheric surface processing technology, and the engineering realizability is strong;

[0034] (3) the application does not use cemented lenses in the light path, avoiding the risk of falling off of the cemented layer;

[0035] (4) the application uses multiple glass materials to match the athermalization material, considering the relatively harsh factors of the space environment relative to the ground environment, and can realize passive athermalization and clear imaging in a wide temperature range; through the mutual matching of different materials, the lens ensures high imaging quality in a wide temperature range of-40℃ to 60℃;

[0036] (5) the application uses two pieces of low-dispersion low-refractive-index material to correct the lateral chromatic aberration of the lens, meeting the design requirements of a wide spectral range. BRIEF DESCRIPTION OF DRAWINGS

[0037] The application will be further described below with reference to the drawings.

[0038] Figure 1 is a structure schematic diagram of an athermalization wide spectral range low-distortion wide-angle lens of the application;

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

[0040] Figure 3 is a modulation transfer function (MTF) curve of the first embodiment of the application at-40℃;

[0041] Figure 4 is a modulation transfer function (MTF) curve of the first embodiment of the application at 0℃;

[0042] Figure 5 is a modulation transfer function (MTF) curve of the first embodiment of the application at 20℃;

[0043] Figure 6 is a modulation transfer function (MTF) curve of the first embodiment of the application at 60℃;

[0044] Figure 7 is a relative distortion curve of the first embodiment of the application;

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

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

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

[0048] Figure 11 2 is a modulation transfer function (MTF) curve of the second embodiment of the present invention at 20°C;

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

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

[0051] Figure 14 This is the 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 clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making any creative efforts shall fall 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. The wide-angle lens includes 11 lenses, two of which are aspherical and the rest are spherical. It adopts a reverse 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. 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, with a convex object-side surface and a concave image-side surface. 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, with a convex object-side surface and a concave image-side surface. 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. Its object-side surface is flat and its image-side surface is concave. The absolute value of the optical 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 biconcave lens with negative optical power. Both the object-side surface and the image-side surface are concave. The absolute value of the optical power is 0.01≤≤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 element 15 is a meniscus lens with positive power. Its object-side surface is concave and its image-side surface is convex. The absolute value of the optical power is 0.005≤≤0.015. The refractive index range of the fifth lens element 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, with both the object-side surface and the image-side surface being convex. 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 element 21 is a meniscus lens with negative power. Its object-side surface is concave and its image-side surface is convex. The absolute value of the optical power is 0.005≤≤0.01. The refractive index range of the seventh lens element 21 is 1.75≤n≤1.85, and the dispersion range is 30≤ν≤40.

[0063] The eighth lens 22 is a biconvex lens with negative optical power. Both the object-side surface and the image-side surface are convex. The absolute value of the optical power is 0.04≤≤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 element 23 is a biconcave lens with negative optical power. 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 element 23 is 1.80≤n≤1.85, and the dispersion range is 35≤ν≤50.

[0065] The tenth lens 24 is a biconvex lens with negative optical power, with both the object side surface and the image side surface being convex. The absolute value of the optical power is 0.01≤≤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 biconvex lens with negative optical power, with both the object-side surface and the image-side surface being convex. 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 the following relationship: 4 ≤ f / EPD. The back focus distance (BFL) and total optical length (TTL) of the athermal, wide-spectrum, low-distortion wide-angle lens provided by the present invention satisfy the following relationship: 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 the following relationship: 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 height, 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] Example 1

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

[0073] In this embodiment, the second lens 12 preferably has an absolute value of optical power of 0.023. In this embodiment, the second lens 12 is preferably made of N-SK2 glass material, which has 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, which has a refractive index of 1.80 and a dispersion of 34.97.

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

[0078] In this embodiment, the seventh lens element 21 preferably has an absolute value of optical power of 0.007. In this embodiment, the seventh lens element 21 is preferably made of H-ZLAF66 glass material, which has 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, which has 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, which has 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, which has 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, which has 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 wide-spectrum low-distortion wide-angle lens provided in this embodiment has an effective focal length of f=7 mm, a full field of view angle of 122°, an operating band of 440-910 nm, an aperture number, that is, a ratio of the effective focal length f to the entrance pupil diameter EPD of 4.5, a total optical length of 350 mm, a clear aperture of the first lens (11) of 205 mm, 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 design requirements such as a large field of view, athermalization, low distortion, and high resolution.

[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 temperatures of -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 The figure shows that at a spatial frequency of 25l p / mm, the MTF of all fields of view is greater than 0.60 under different temperature conditions. Compared with the standard temperature of 20°C, the drop in MTF at different temperatures does not exceed 0.1, indicating that the lens can produce clear images across the entire image plane and has good athermal performance.

[0087] like Figure 7 FIG. 1 shows the distortion curve of the athermal, wide-spectrum, low-distortion wide-angle lens provided in this embodiment. The horizontal axis represents relative distortion, and the vertical axis represents field of view. Figure 7 It is shown in FIG. 1 that the relative distortion DI ST of the athermal, wide-spectrum, low-distortion wide-angle lens provided by this embodiment is less than 2% in all fields of view.

[0088] like Figure 8 FIG. 1 shows a 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 FIG. 1 that the lateral chromatic aberration of the athermal, wide-spectrum, low-distortion wide-angle lens provided in this embodiment is less than 6 μm, and the lateral chromatic aberration is well corrected.

[0089] Example 2

[0090] The first lens 11 of the embodiment preferably has an absolute value of 0.0056 of the optical power. The first lens 11 of the embodiment preferably has a glass material of the S IL I CA type, which has a refractive index of 1.46 and a dispersion of 67.82.

[0091] The second lens 12 of the embodiment preferably has an absolute value of 0.025 of the optical power. The second lens 12 of the embodiment preferably has a glass material of the N-SK4 type, which has a refractive index of 1.61 and a dispersion of 58.63.

[0092] The third lens 13 of the embodiment preferably has an absolute value of 0.014 of the optical power. The third lens 13 of the embodiment preferably has a glass material of the N-SK4 type, which has a refractive index of 1.61 and a dispersion of 58.63.

[0093] The fourth lens 14 of the embodiment preferably has an absolute value of 0.021 of the optical power. The fourth lens 14 of the embodiment preferably has a glass material of the H-ZLAF53B type, which has a refractive index of 1.84 and a dispersion of 37.23.

[0094] The fifth lens 15 of the embodiment preferably has an absolute value of 0.013 of the optical power. The fifth lens 15 of the embodiment preferably has a glass material of the H-LAF53 type, which has a refractive index of 1.74 and a dispersion of 49.24.

[0095] The sixth lens 16 of the embodiment preferably has an absolute value of 0.013 of the optical power. The sixth lens 16 of the embodiment preferably has a glass material of the H-LAF53 type, which has a refractive index of 1.74 and a dispersion of 49.24.

[0096] The seventh lens 21 of the embodiment preferably has an absolute value of 0.009 of the optical power. The seventh lens 21 of the embodiment preferably has a glass material of the H-ZLAF53B type, which has a refractive index of 1.84 and a dispersion of 37.23.

[0097] The eighth lens 22 of the embodiment preferably has an absolute value of 0.078 of the optical power. The eighth lens 22 of the embodiment preferably has a glass material of the CAF2 type, which has a refractive index of 1.44 and a dispersion of 95.00.

[0098] The ninth lens 23 of the embodiment preferably has an absolute value of 0.098 of the optical power. The ninth lens 23 of the embodiment preferably has a glass material of the N-LASF41 type, which has a refractive index of 1.84 and a dispersion of 43.13.

[0099] The tenth lens 24 of the embodiment preferably has an absolute value of 0.032 of the optical power. The tenth lens 24 of the embodiment preferably has a glass material of the CAF2 type, which has 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, which has 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 this embodiment is f=5mm, the full field of view angle is 118°, the operating 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 distance 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 this embodiment can meet design requirements such as large field of view, athermal difference, low distortion, and high resolution.

[0104] Such as Figures 9-12 Shown are modulation transfer function (MTF) curves for the athermalized, wide-spectrum, low-distortion wide-angle lens of this embodiment at temperatures of -40°C, 0°C, 20°C, and 60°C. The abscissa represents spatial frequency in line pairs per millimeter (lp / mm), while the ordinate represents the MTF value. The graph shows that at a spatial frequency of 35 lp / mm, the MTF is greater than 0.60 across all fields of view at different temperatures. Compared to the standard temperature of 20°C, the MTF decreases by no more than 0.1 at different temperatures, demonstrating that the lens produces clear images across the entire image plane and exhibits excellent athermal performance.

[0105] like Figure 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 for all fields of view is less than 2%.

[0106] like Figure 14 FIG. 1 shows a 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 14 It is shown in FIG. 1 that the lateral chromatic aberration of the athermal, wide-spectrum, low-distortion wide-angle lens provided by this embodiment is less than 5 μm, and the lateral chromatic aberration is well corrected.

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

[0108] The above detailed description of the preferred embodiments of the present invention should not 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 patent of the present invention.

Claims

1. An athermal, wide-band, low-distortion, wide-angle lens, characterized by: The optical system comprises 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) comprises: A first lens (11) with negative optical power, wherein the object side surface is convex, the 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, wherein the object side surface is convex, the image side surface is concave, and the absolute value of the optical power is 0.01≤≤0.03; a third lens (13) having negative optical power, wherein the object side surface is a flat surface, the image side surface is a concave surface, and the absolute value of the optical power is 0.005≤≤0.02; a fourth lens (14) having negative optical power, wherein both the object side surface and the image side surface are concave, and the absolute value of the optical power is 0.01≤≤0.03; a fifth lens (15) having positive refractive power, wherein the object side surface is concave, the image side surface is convex, and the absolute value of the refractive power is 0.005≤≤0.015; a sixth lens (16) having positive refractive power, wherein 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; The rear lens group (2) comprises: a seventh lens (21) having negative optical power, wherein the object side surface is concave, the image side surface is convex, and the absolute value of the optical power is 0.005≤≤0.01; An eighth lens (22) having positive refractive power, wherein both the object side surface and the image side surface are convex, and the absolute value of the refractive power is 0.04≤≤0.08; A ninth lens (23) having negative optical power, wherein both the object side surface and the image side surface are concave, and the absolute value of the optical power is 0.06≤≤0.10; A tenth lens (24) having positive optical power, wherein both the object side surface and the image side surface are convex, and the absolute value of the optical power is 0.01≤≤0.04; an eleventh lens (25) having positive refractive power, wherein both the object side surface and the image side surface are 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; The wide-angle lens has a total of eleven lenses.

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 the following: 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 height, 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 μm.

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