A wide-spectrum pyrometric long-wave infrared characteristic measurement lens

Abstract

This invention relates to the field of optical lens technology, and particularly to a wide-spectrum thermally ablated long-wave infrared characteristic measurement lens, comprising: an electromagnetic shielding window, a filter, a lens group, a detector protective glass, a detector filter, and a focal plane arranged sequentially along the optical axis from the object side to the image side; the lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object side to the image side; the first lens is an even-order aspherical negative lens; the second lens is an even-order aspherical positive lens; the third lens is a plano-concave even-order aspherical negative lens; and the fourth lens is a plano-convex even-order aspherical positive lens. This lens combines a wide spectral band, a large thermally ablated range, and electromagnetic shielding function, exhibiting excellent environmental adaptability and meeting the high-quality imaging requirements of different space environments. It can be applied to acquire wide-spectrum infrared characteristic data of targets in space environments.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and in particular to a wide-spectrum pyrometric long-wave infrared characteristic measurement lens. Background Technology

[0002] Due to the influence of the atmospheric window (8μm–14μm in long-wave infrared), the spectral response range of commonly used cooled long-wave infrared detectors is 7.7μm–9.5μm or 7.7μm–10.3μm, while that of uncooled long-wave infrared detectors is 8μm–14μm. To obtain richer characteristic data of the target, it is necessary to broaden the spectral response band of the detector; however, ordinary infrared optical lenses are not suitable for broadband imaging. Furthermore, ordinary lenses generally only consider ground environmental conditions and can only achieve high-quality imaging in ground environments, failing to meet the requirements of high-quality imaging and broadband characteristic observation and measurement in space environments.

[0003] Therefore, there is an urgent need to provide a long-wave infrared characteristic measurement lens that can be applied to the observation and measurement of the wide spectrum characteristics of the space environment. Summary of the Invention

[0004] To address one or more technical problems in the prior art, this invention provides a wide-band pyrometric long-wave infrared characteristic measurement lens. This lens combines a wide spectral band, a large pyrometric range, and electromagnetic shielding, exhibiting excellent environmental adaptability. It can meet the high-quality imaging requirements of different space environments and can be applied to acquire wide-spectrum infrared characteristic data of targets in space environments. This solves the problem that existing ordinary long-wave infrared optical lenses have a narrow spectral range and cannot be applied to the observation and measurement of wide-spectrum characteristics in space environments.

[0005] To achieve the above objectives, the present invention provides a broadband thermally ablated long-wave infrared characteristic measurement lens, comprising: an electromagnetic shielding window, a filter, a lens group, a detector protective glass, a detector filter, and a focal plane arranged sequentially along the optical axis from the object side to the image side;

[0006] The lens group comprises a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object side to the image side; the first lens is an even-order aspherical negative lens; the second lens is an even-order aspherical positive lens; the third lens is a plano-concave even-order aspherical negative lens; and the fourth lens is a plano-convex even-order aspherical positive lens; the lens group satisfies the following relationship:

[0007] BF / f = 1.679

[0008] f1 / f = -0.95

[0009] f² / f = 1.58

[0010] f3 / f = -5.36

[0011] f4 / f = 1.06

[0012] n1=n2=4, n3=2.21, n4=2.78

[0013] d1 / f = 0.375

[0014] d² / f = 0.733

[0015] d3 / f = 0.1

[0016] Where BF is the back focal length of the lens, f is the total focal length of the lens, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, n3 is the refractive index of the third lens, n4 is the refractive index of the fourth lens, d1 is the air gap between the first and second lenses, d2 is the air gap between the second and third lenses, and d3 is the air gap between the third and fourth lenses.

[0017] In one possible design, the working wavelength of the broadband anechoic long-wave infrared characteristic measurement lens is 6μm to 12μm, the field of view is φ40°, the focal length is 24mm, the F number is 2, the distortion is less than 3%, the anechoic temperature range is -40℃ to 60℃, and the cold aperture is matched 100%.

[0018] In one possible design, the side of the electromagnetic shielding window closest to the image is coated with a metal mesh; the outer ring of the metal mesh is coated with a metal ring; preferably, the diameter of the electromagnetic shielding window is 43 mm; the diameter of the metal mesh is 40 mm; and the width of the metal ring is 1.5 mm.

[0019] In one possible design, both sides of the electromagnetic shielding window are coated with antireflective films; the electromagnetic shielding window has an average spectral transmittance of ≥86% in the 6μm~12μm band and an electric field radiation shielding effectiveness of ≥30dB in the 30MHz~1.5GHz band.

[0020] In one possible design, the first lens has a spherical surface on the object side and an even-order aspherical surface on the image side.

[0021] The second lens has an even-order aspherical surface on the object side and a spherical surface on the image side.

[0022] The third lens has a planar surface on the object side and an even-order aspherical surface on the image side; and / or

[0023] The fourth lens has a plane on the object side and an even-order aspherical surface on the image side.

[0024] In one possible design, the radius of curvature of the first lens near the object side is 38.678 mm, and the radius of curvature of the lens near the image side is 23.304 mm.

[0025] The radius of curvature of the second lens on the object side is 63.381 mm, and the radius of curvature of the lens on the image side is 137.128 mm.

[0026] The radius of curvature of the third lens on the image-side surface is 155.83 mm; and / or

[0027] The radius of curvature of the fourth lens on the image side is -45.354 mm.

[0028] In one possible design, the aspherical surfaces of the first lens (image side), the second lens (object side), the third lens (image side), and the fourth lens (image side) conform to the following formula:

[0029] Where Z is the sag, c is the surface curvature, r is the radial distance from a point on the lens to the optical axis, k is the conic coefficient, and a2, a4, a6, and a8 are all aspherical coefficients.

[0030] In one possible design, the image-side surface of the first lens satisfies: a2 = 0, a4 = -2.372E. -6 a6 = -1.631E -8 a8 = 6.877E -11 ;

[0031] The second lens, on the object side, satisfies: a2 = 0, a4 = -2.453E -6 a6 = -1.168E -8 a8 = 2.063E -11 ;

[0032] The third lens, on the image-side surface, satisfies: a2 = 0, a4 = -3.249E. -6 a6 = -2.884E -8 a8 = 9.496E -11 ; and / or

[0033] The fourth lens, on the image side, satisfies: a2 = 0, a4 = 3.283E. -6 a6 = 1.372E -8 a8 = -4.716E -11 .

[0034] In one possible design, the thickness of the first lens is 3mm;

[0035] The thickness of the second lens is 3.3 mm;

[0036] The thickness of the third lens is 6.8 mm; and / or

[0037] The thickness of the fourth lens is 4.7 mm.

[0038] In one possible design, the first lens is made of germanium single crystal;

[0039] The material of the second lens is zinc sulfide;

[0040] The third lens is made of germanium single crystal;

[0041] The fourth lens is made of chalcogenide glass;

[0042] The detector's protective glass is made of germanium crystal; and / or

[0043] The detector filter is made of germanium crystal.

[0044] Compared with the prior art, the present invention has at least the following beneficial effects:

[0045] This invention achieves a wide spectral range and a large thermal aberration range by coordinating the parameters of each lens in the lens group (surface shape, focal length, refractive index, etc.) and the air gap between each lens. It has excellent environmental adaptability and can meet the high-quality imaging requirements of different space environments. It can be applied to acquire broadband infrared characteristic data of targets in space environments, solving the problem that existing ordinary long-wave infrared optical lenses have a narrow spectral range and cannot be used for the observation and measurement of broadband characteristics in space environments. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is the optical path diagram of the broadband thermally reduced long-wave infrared characteristic measurement lens provided by the present invention;

[0048] Figure 2 This is the field curvature and distortion diagram of the wide-spectrum pyrometric difference long-wave infrared characteristic measurement lens of the present invention under normal temperature and pressure;

[0049] Figure 3 This is the MTF curve of the wide-band pyrometric difference long-wave infrared characteristic measurement lens of the present invention under normal temperature and pressure;

[0050] Figure 4This is the MTF curve of the wide-band pyrometric difference long-wave infrared characteristic measurement lens of the present invention at -40℃ and normal pressure;

[0051] Figure 5 This is the MTF curve of the wide-band pyrometric difference long-wave infrared characteristic measurement lens of the present invention at 60℃ and normal pressure;

[0052] Figure 6 This is the MTF curve of the wide-band pyrometric difference long-wave infrared characteristic measurement lens of the present invention under normal temperature and pressure;

[0053] Figure 7 This is the MTF curve of the wide-band pyrometric difference long-wave infrared characteristic measurement lens of the present invention under vacuum at -40℃;

[0054] Figure 8 This is the MTF curve of the wide-spectrum pyrometric difference long-wave infrared characteristic measurement lens of the present invention under vacuum at 60℃.

[0055] Reference numerals: 1-Electromagnetic shielding window, 2-Filter, 3-Lens group, 31-First lens, 32-Second lens, 33-Third lens, 34-Fourth lens, 4-Detector protective glass, 5-Detector filter, 6-Focal plane. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0057] like Figure 1 As shown, in order to achieve the above objectives, the present invention provides a wide-band pyrometric long-wave infrared characteristic measurement lens, comprising: an electromagnetic shielding window 1, a filter 2, a lens group 3, a detector protective glass 4, a detector filter 5, and a focal plane 6 arranged sequentially along the optical axis from the object side to the image side.

[0058] The lens group comprises a first lens 31, a second lens 32, a third lens 33, and a fourth lens 34 arranged sequentially along the optical axis from the object side to the image side; the first lens 31 is an even-order aspherical negative lens; the second lens 32 is an even-order aspherical positive lens; the third lens 33 is a plano-concave even-order aspherical negative lens; and the fourth lens 34 is a plano-convex even-order aspherical positive lens; the lens group 3 satisfies the following relationship:

[0059] BF / f = 1.679

[0060] f1 / f=-0.95, f2 / f=1.58, f3 / f=-5.36, f4 / f=1.06

[0061] n1=n2=4, n3=2.21, n4=2.78

[0062] d1 / f=0.375, d2 / f=0.733, d3 / f=0.1

[0063] Where BF is the back focal length of the lens, f is the total focal length of the lens, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, n3 is the refractive index of the third lens, n4 is the refractive index of the fourth lens, d1 is the air gap between the first and second lenses, d2 is the air gap between the second and third lenses, and d3 is the air gap between the third and fourth lenses.

[0064] This invention achieves a wide spectral range and a large thermal aberration range by coordinating the parameters of each lens in the lens group (surface shape, focal length, refractive index, etc.) and the air gap between each lens. It has excellent environmental adaptability and can meet the high-quality imaging requirements of different space environments. It can be applied to acquire broadband infrared characteristic data of targets in space environments, solving the problem that existing ordinary long-wave infrared optical lenses have a narrow spectral range and cannot be used for the observation and measurement of broadband characteristics in space environments.

[0065] In some preferred embodiments, the broadband thermally adiabatic long-wave infrared characteristic measurement lens operates in the wavelength range of 6μm to 12μm, has a field of view of φ40°, a focal length of 24mm, an F-number of 2, distortion of less than 3%, an anechoic temperature range of -40℃ to 60℃, and 100% cold stop matching. It should be noted that φ40° refers to a field of view with a conic angle of 40°.

[0066] In some preferred embodiments, the side of the electromagnetic shielding window 1 closest to the image is coated with a metal mesh; the outer ring of the metal mesh is coated with a metal ring; preferably, the diameter of the electromagnetic shielding window 1 is 43 mm; the diameter of the metal mesh is 40 mm; and the width of the metal ring is 1.5 mm.

[0067] The electromagnetic shielding window of this invention uses zinc sulfide as a substrate, and then a metal mesh is plated on the surface of the zinc sulfide substrate. The electromagnetic shielding function is achieved by plating the metal mesh on the surface of the zinc sulfide substrate. Then, an anti-reflection film is plated on both sides of the electromagnetic shielding window with the metal mesh to increase the light transmittance.

[0068] In some preferred embodiments, both sides of the electromagnetic shielding window 1 are coated with an antireflective film; the electromagnetic shielding window has an average spectral transmittance of ≥86% in the 6μm to 12μm band and an electric field radiation shielding effectiveness of ≥30dB in the 30MHz to 1.5GHz band.

[0069] In some preferred embodiments, the filter 2 can be for the 6μm to 12μm band, or different smaller bands can be selected in the 6μm to 12μm band. The filter films corresponding to different bands are installed on the filter wheel to achieve multi-band selection.

[0070] In some preferred embodiments, the side of the first lens closest to the object side is a spherical surface, and the side closest to the image side is an even-order aspherical surface.

[0071] In some preferred embodiments, the second lens 32 has an even-order aspherical surface on the object side and a spherical surface on the image side.

[0072] In some preferred embodiments, the third lens 33 has a planar surface on the object side and an even-order aspherical surface on the image side.

[0073] In some preferred embodiments, the fourth lens 34 has a planar surface on the object side and an even-order aspherical surface on the image side.

[0074] In some preferred embodiments, the radius of curvature of the first lens 31 near the object side is 38.678 mm, and the radius of curvature of the lens near the image side is 23.304 mm.

[0075] In some preferred embodiments, the radius of curvature of the second lens 32 near the object side is 63.381 mm, and the radius of curvature of the second lens near the image side is 137.128 mm.

[0076] In some preferred embodiments, the radius of curvature of the third lens 33 on the image side is 155.83 mm.

[0077] In some preferred embodiments, the radius of curvature of the fourth lens 34 on the image side is -45.354 mm.

[0078] In some preferred embodiments, the aspherical surfaces of the first lens 31 (image side), the second lens 32 (object side), the third lens 33 (image side), and the fourth lens 34 (image side) conform to the following formula:

[0079] Where Z is the sag, c is the surface curvature, r is the radial distance from a point on the lens to the optical axis, k is the conic coefficient, and a2, a4, a6, and a8 are all aspherical coefficients.

[0080] In some preferred embodiments, the side of the first lens 31 closest to the image side satisfies: a 2＝0 a4 = -2.372E -6 a6 = -1.631E -8 a8 = 6.877E -11 .

[0081] In some preferred embodiments, the side of the second lens 32 closest to the object side satisfies: a 2＝0 a4 = -2.453E -6 a6 = -1.168E -8 a8 = 2.063E -11 .

[0082] In some preferred embodiments, the third lens 33 near the image side satisfies: a 2＝0 a4 = -3.249E -6 a6 = -2.884E -8 a8 = 9.496E -11 .

[0083] The fourth lens 34, on the image side, satisfies: a 2＝0， a4 = 3.283E -6 a6 = 1.372E -8 a8 = -4.716E -11 .

[0084] In some preferred embodiments, the thickness of the first lens 31 is 3 mm.

[0085] In some preferred embodiments, the thickness of the second lens 32 is 3.3 mm.

[0086] In some preferred embodiments, the thickness of the third lens 33 is 6.8 mm.

[0087] In some preferred embodiments, the thickness of the fourth lens 34 is 4.7 mm.

[0088] In some preferred embodiments, the first lens 31 is made of germanium single crystal.

[0089] In some preferred embodiments, the material of the second lens 32 is zinc sulfide.

[0090] In some preferred embodiments, the third lens 33 is made of germanium single crystal.

[0091] In some preferred embodiments, the fourth lens 34 is made of chalcogenide glass, preferably Xinhua Optoelectronics chalcogenide glass IRG206.

[0092] In some preferred embodiments, the focal length of the first lens 31 is -22.8 mm.

[0093] In some preferred embodiments, the focal length of the second lens 32 is 37.92 mm.

[0094] In some preferred embodiments, the focal length of the third lens 33 is -128.64 mm.

[0095] In some preferred embodiments, the focal length of the fourth lens 34 is 25.44 mm.

[0096] In some preferred embodiments, the detector protective glass 4 is a germanium crystal, and the thickness of the detector protective glass is preferably 2.5 mm.

[0097] In some preferred embodiments, the detector filter 5 is a germanium crystal, and the thickness of the detector filter is preferably 0.3 mm.

[0098] In a specific embodiment of the present invention, a broadband thermally ablated long-wave infrared characteristic measurement lens includes: an electromagnetic shielding window 1, a filter 2, a lens group 3, a detector protective glass 4, a detector filter 5, and a focal plane 6 arranged sequentially along the optical axis from the object side to the image side.

[0099] The electromagnetic shielding window 1 (with zinc sulfide as the base and an aperture of 43 mm) has a metal mesh (40 mm in diameter) on the side closest to the image; the outer ring of the metal mesh is coated with a metal ring (1.5 mm wide); both sides of the electromagnetic shielding window are coated with an anti-reflection film; the electromagnetic shielding window 1 has an average spectral transmittance of ≥86% in the 6 μm to 12 μm band and an electric field radiation shielding effectiveness of ≥30 dB in the 30 MHz to 1.5 GHz band.

[0100] The lens group 3 includes a first lens 31 (a germanium single crystal aspherical negative lens with a thickness of 3 mm), a second lens 32 (a zinc sulfide even-order aspherical positive lens with a thickness of 3.3 mm), a third lens 33 (a germanium single crystal plano-concave even-order aspherical negative lens with a thickness of 6.8 mm) and a fourth lens 34 (a chalcogenide glass plano-convex even-order aspherical positive lens with a thickness of 4.7 mm) arranged sequentially along the optical axis from the object side to the image side.

[0101] The lens group satisfies the following relationship:

[0102] BF / f = 1.679

[0103] f1 / f=-0.95, f2 / f=1.58, f3 / f=-5.36, f4 / f=1.06

[0104] n1=n2=4, n3=2.21, n4=2.78

[0105] d1 / f=0.375, d2 / f=0.733, d3 / f=0.1

[0106] Where BF is the back focal length of the lens, f is the total focal length of the lens, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, n3 is the refractive index of the third lens, n4 is the refractive index of the fourth lens, d1 is the air gap between the first and second lenses, d2 is the air gap between the second and third lenses, and d3 is the air gap between the third and fourth lenses.

[0107] The first lens 31 has a spherical surface (radius of curvature of 38.678 mm) on the object side and an even-order aspherical surface (radius of curvature of 23.304 mm) on the image side; the second lens 32 has an even-order aspherical surface (radius of curvature of 63.381 mm) on the object side and a spherical surface (radius of curvature of 137.128 mm) on the image side; the third lens 33 has a plane (radius of curvature of ∞) on the object side and an even-order aspherical surface (radius of curvature of 155.83 mm) on the image side; the fourth lens 34 has a plane (radius of curvature of ∞) on the object side and an even-order aspherical surface (radius of curvature of -45.354 mm) on the image side.

[0108] The aspherical surfaces of the first lens 31 (image side), the second lens 32 (object side), the third lens 33 (image side), and the fourth lens 34 (image side) conform to the following formula: Where Z is the sag, c is the surface curvature, r is the radial distance from a point on the lens to the optical axis, k is the conic coefficient, and a2, a4, a6, and a8 are aspherical coefficients. The image-side surface of the first lens satisfies: a 2＝0 a4 = -2.372E -6 a6 = -1.631E -8 a8 = 6.877E -11 The second lens, on the object side, satisfies: a 2＝0 a4 = -2.453E -6 a6 = -1.168E -8 a8 = 2.063E -11 The third lens, on the image side, satisfies: a 2＝0 a4 = -3.249E -6 a6 = -2.884E -8 a8 = 9.496E -11 The fourth lens, on the image side, satisfies: a 2＝0 a4 = 3.283E -6a6 = 1.372E -8 a8 = -4.716E -11 .

[0109] The detector protective glass 4 is a germanium crystal with a thickness of 2.5 mm, the detector filter 5 is a germanium crystal with a thickness of 0.3 mm, and the focal plane 6 is the photosensitive surface of the detector, used to receive infrared radiation signals.

[0110] The working wavelength of this wide-band thermally adiabatic long-wave infrared characteristic measurement lens is 6μm~12μm, with a field of view of φ40°, a focal length of 24mm, an F number of 2, distortion of less than 3%, an anechoic temperature range of -40℃~60℃, and 100% cold aperture matching.

[0111] Depend on Figure 2 It can be seen that the distortion of the broadband pyrometric long-wave infrared characteristic measurement lens provided in this embodiment of the invention is small (less than 3%). Figure 3-8 It can be seen that under normal temperature and pressure, -40℃, 60℃ normal pressure, normal temperature vacuum, -40℃ vacuum, and 60℃ vacuum conditions, the MTF curve of this lens is close to the diffraction-limited curve, indicating that the lens can achieve thermalization under normal pressure and vacuum conditions of -40~60℃, and can meet the high-quality imaging requirements under normal pressure and vacuum conditions of -40~60℃. Therefore, the broadband thermally differential long-wave infrared characteristic measurement lens provided by this invention has good environmental adaptability and can meet the high-quality imaging requirements under different environmental conditions.

[0112] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A broadband pyrometric long-wave infrared characteristic measurement lens, characterized in that, include: The electromagnetic shielding window, filter, lens group, detector protective glass, detector filter and focal plane are arranged sequentially along the optical axis from the object side to the image side; The lens group consists of a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object side to the image side; the first lens is an even-order aspherical negative lens; the second lens is an even-order aspherical positive lens; the third lens is a plano-concave even-order aspherical negative lens; and the fourth lens is a plano-convex even-order aspherical positive lens; the lens group satisfies the following relationship: in, BF The rear focal length of the lens. f The total focal length of the lens. f 1 represents the focal length of the first lens. f 2 represents the focal length of the second lens. f 3 represents the focal length of the third lens. f 4 represents the focal length of the fourth lens. n 1 represents the refractive index of the first lens. n 2 represents the refractive index of the second lens. n 3 represents the refractive index of the third lens. n 4 represents the refractive index of the fourth lens. d 1 represents the air gap distance between the first lens and the second lens. d 2 represents the air gap distance between the second and third lenses. d 3 represents the air gap distance between the third and fourth lenses.

2. The broadband pyrometric long-wave infrared characteristic measurement lens according to claim 1, characterized in that, The wide-spectrum calorimetric long-wave infrared characteristic measurement lens operates in the band of 6μm~12μm, has a field of view of φ40°, a focal length of 24mm, an F number of 2, distortion of less than 3%, an anechoic temperature range of -40℃~60℃, and 100% cold aperture matching.

3. The broadband pyrometric long-wave infrared characteristic measurement lens according to claim 1, characterized in that, The electromagnetic shielding window has a metal mesh plated on the side closest to the image; the outer ring of the metal mesh plated with a metal ring; the diameter of the electromagnetic shielding window is 43mm; the diameter of the metal mesh is 40mm; and the width of the metal ring is 1.5mm.

4. The broadband pyrometric long-wave infrared characteristic measurement lens according to claim 1, characterized in that, Both sides of the electromagnetic shielding window are coated with antireflective film; the electromagnetic shielding window has an average spectral transmittance of ≥86% in the 6μm~12μm band and an electric field radiation shielding effectiveness of ≥30dB in the 30MHz~1.5GHz band.

5. The broadband pyrometric long-wave infrared characteristic measurement lens according to claim 1, characterized in that, The first lens has a spherical surface on the object side and an even-order aspherical surface on the image side; and / or The second lens has an even-order aspherical surface on the object side and a spherical surface on the image side; and / or The third lens has a planar surface on the object side and an even-order aspherical surface on the image side; and / or The fourth lens has a plane on the object side and an even-order aspherical surface on the image side.

6. The broadband pyrometric long-wave infrared characteristic measurement lens according to claim 5, characterized in that, The radius of curvature of the first lens near the object side is 38.678 mm, and the radius of curvature of the lens near the image side is 23.304 mm; and / or The second lens has a radius of curvature of 63.381 mm on the object side and a radius of curvature of 137.128 mm on the image side; and / or The radius of curvature of the third lens on the image side is 155.83 mm; and / or The radius of curvature of the fourth lens on the image side is -45.354 mm.

7. The broadband pyrometric long-wave infrared characteristic measurement lens according to claim 5, characterized in that, The aspherical surfaces of the first lens (image side), the second lens (object side), the third lens (image side), and the fourth lens (image side) conform to the following formula: Where Z is the height of the arrow. c For surface curvature, r It is the radial distance from a point on the lens to the optical axis. k The conic coefficient, a 2. a 4. a 6. a All 8 are aspherical coefficients.

8. The broadband pyrometric long-wave infrared characteristic measurement lens according to claim 7, characterized in that, The image-side surface of the first lens satisfies: a2=0, a4=-2.372E -6 a6 = -1.631E -8 a8 = 6.877E -11 ; and / or The second lens, on the object side, satisfies: a2=0, a4=-2.453E. -6 a6 = -1.168E -8 a8 = 2.063E -11 ; and / or The third lens, on the image-side surface, satisfies: a2=0, a4=-3.249E. -6 a6 = -2.884E -8 a8 = 9.496E -11 ; and / or The fourth lens, on the image-side surface, satisfies: a2=0, a4=3.283E. -6 a6 = 1.372E -8 a8 = -4.716E -11 .

9. The broadband pyrometric long-wave infrared characteristic measurement lens according to claim 1, characterized in that, The thickness of the first lens is 3 mm; and / or The thickness of the second lens is 3.3 mm; and / or The thickness of the third lens is 6.8 mm; and / or The thickness of the fourth lens is 4.7 mm.

10. The broadband pyrometric long-wave infrared characteristic measurement lens according to claim 1, characterized in that, The first lens is made of germanium single crystal; and / or The material of the second lens is zinc sulfide; and / or The third lens is made of germanium single crystal; and / or The fourth lens is made of chalcogenide glass; and / or The detector's protective glass is made of germanium crystal; and / or The material of the detector filter is germanium crystal.

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