Long-wave infrared spectral imaging lens

Abstract

The present invention relates to the field of optical lenses, and provides a long-wave infrared spectral imaging lens for long-wave infrared spectral imaging. From the object plane to the image plane, it sequentially includes a diaphragm, a first meniscus lens, a second meniscus lens, a third meniscus lens, a fourth meniscus lens, a fifth meniscus lens, a Dewar window, and an integrated filter, which are coaxially arranged; the first meniscus lens is a positive lens, the second meniscus lens is a negative lens, the third meniscus lens is a positive lens, the fourth meniscus lens is a positive lens, and the fifth meniscus lens is a negative lens; the side of the first meniscus lens close to the object plane is an even aspherical surface, and the side of the fourth meniscus lens close to the object plane is an even aspherical surface. To solve the defect that the long-wave infrared lens in the related technology performs poorly in radiation calibration, which will affect the imaging quality. The solution of this application can facilitate blackbody calibration and achieve better matching with the front-end system, meet the requirements of high-precision calibration, and thus improve the imaging quality.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and in particular, to a long-wave infrared spectral imaging lens. Background Art

[0002] 8 - 14μm is the atmospheric window of long-wave infrared, and it is also the band where the thermal radiation energy of normal-temperature objects is concentrated. Long-wave infrared has strong penetration ability, and its penetration depth is much deeper than that of medium-wave infrared and short-wave infrared. It can observe ground objects under weather conditions such as clouds, haze, rain, and snow. In terms of applications, infrared long-wave lenses can be used in fields such as all-weather surveillance, space remote sensing detection, fire monitoring, and infrared astronomy.

[0003] With the development of long-wave infrared detectors, the accuracy requirements for detection targets are also getting higher and higher. The accuracy of radiation correction and radiometric calibration directly affects the quality of images. Common methods include laboratory calibration, on-aircraft / on-satellite calibration, and field calibration, etc. However, the long-wave infrared lenses in related technologies perform poorly in radiometric calibration, which will in turn affect the imaging quality. Summary of the Invention

[0004] The present invention provides a long-wave infrared spectral imaging lens to solve the defect that the long-wave infrared lenses in related technologies perform poorly in radiometric calibration, which will in turn affect the imaging quality. The solution of the present application can facilitate blackbody calibration and achieve better matching with the front-end system, meeting the high-precision calibration requirements. And by restricting the light, a real exit pupil is formed at the Dewar window, achieving an approximate 100% cold stop match.

[0005] The present invention provides a long-wave infrared spectral imaging lens for long-wave infrared spectral imaging. From the object plane to the image plane, it sequentially includes a diaphragm, a first meniscus lens, a second meniscus lens, a third meniscus lens, a fourth meniscus lens, a fifth meniscus lens, a Dewar window, and an integrated filter, which are coaxially arranged;

[0006] The first meniscus lens is a positive lens, the second meniscus lens is a negative lens, the third meniscus lens is a positive lens, the fourth meniscus lens is a positive lens, and the fifth meniscus lens is a negative lens;

[0007] The side of the first meniscus lens close to the object plane is an even aspheric surface, the side of the fourth meniscus lens close to the object plane is an even aspheric surface, and the second meniscus lens, the third meniscus lens, and the fifth meniscus lens are all spherical mirrors.

[0008] According to the long-wave infrared spectral imaging lens provided by the present invention, the central thickness d1 of the first meniscus lens satisfies 14 mm ≤ d1 ≤ 18 mm;

[0009] The central thickness d2 of the second meniscus lens satisfies 5 mm ≤ d2 ≤ 10 mm;

[0010] The central thickness d3 of the third meniscus lens satisfies 5 mm ≤ d3 ≤ 10 mm;

[0011] The central thickness d4 of the fourth meniscus lens satisfies 4 mm ≤ d4 ≤ 8 mm;

[0012] The central thickness d5 of the fifth meniscus lens satisfies 5 mm ≤ d5 ≤ 10 mm.

[0013] For the long-wave infrared spectral imaging lens provided by the present invention, the distance p1 from the object-side of the first meniscus lens to the aperture stop satisfies 50 mm ≤ p1 ≤ 70 mm;

[0014] The distance p2 from the object-side of the second meniscus lens to the image-side of the first meniscus lens satisfies 20 mm ≤ p2 ≤ 30 mm;

[0015] The distance p3 from the object-side of the third meniscus lens to the image-side of the second meniscus lens satisfies 30 mm ≤ p3 ≤ 40 mm;

[0016] The distance p4 from the object-side of the fourth meniscus lens to the image-side of the third meniscus lens satisfies 80 mm ≤ p4 ≤ 90 mm;

[0017] The distance p5 from the object-side of the fifth meniscus lens to the image-side of the fourth meniscus lens satisfies 2 mm ≤ p5 ≤ 7 mm;

[0018] The distance p6 from the object-side of the Dewar to the image-side of the fifth meniscus lens satisfies 2 mm ≤ p5 ≤ 10 mm;

[0019] The distance p7 from the object-side of the integrated filter to the image-side of the Dewar window satisfies 30 mm ≤ p5 ≤ 40 mm;

[0020] The distance p8 from the image plane to the image-side of the Dewar window satisfies 0 mm ≤ p5 ≤ 1 mm;

[0021] For the long-wave infrared spectral imaging lens provided by the present invention, the radius of curvature R1 of the object-side of the first meniscus lens satisfies 80 mm ≤ R1 ≤ 90 mm;

[0022] The radius of curvature R2 of the image-side of the first meniscus lens satisfies 150 mm ≤ R2 ≤ 160 mm;

[0023] The radius of curvature R3 of the object-side of the second meniscus lens satisfies 24 mm ≤ R3 ≤ 27 mm;

[0024] The radius of curvature R4 of the image-side of the second meniscus lens satisfies 15 mm ≤ R4 ≤ 20 mm;

[0025] The radius of curvature R5 on the object surface side of the third meniscus lens satisfies -60 mm ≤ R5 ≤ -50 mm;

[0026] The radius of curvature R6 on the image surface side of the third meniscus lens satisfies -50 mm ≤ R6 ≤ -40 mm;

[0027] The radius of curvature R7 on the object surface side of the fourth meniscus lens satisfies 50 mm ≤ R7 ≤ 60 mm;

[0028] The radius of curvature R8 on the image surface side of the fourth meniscus lens satisfies 90 mm ≤ R8 ≤ 100 mm;

[0029] The radius of curvature R9 on the object surface side of the fifth meniscus lens satisfies -160 mm ≤ R9 ≤ -150 mm;

[0030] The radius of curvature R10 on the image surface side of the fifth meniscus lens satisfies -135 mm ≤ R10 ≤ -130 mm.

[0031] For the long-wave infrared spectral imaging lens provided by the present invention, the aspheric surface shapes on the object surface side of the first meniscus lens and on the object surface side of the fourth meniscus lens conform to the following formula:

[0032]

[0033] where Z is the sag height, c is the curvature, r is the radial distance from a certain point on the lens to the optical axis, k is the conic coefficient, a 4 、a 6 and a 8 are all aspheric coefficients.

[0034] For the long-wave infrared spectral imaging lens provided by the present invention, the object surface side of the first meniscus lens satisfies:

[0035] a4 = 7.26E -8 , a6 = 4.36E -12 , a8 = 5.75E -15 , k = -1.37.

[0036] For the long-wave infrared spectral imaging lens provided by the present invention, the object surface side of the fourth meniscus lens satisfies:

[0037] a4 = 6.30E -6 , a6 = -5.80E -9 , a8 = 3.87E -12 , k = -8.71.

[0038] For the long-wave infrared spectral imaging lens provided by the present invention, the focal length f1 of the first meniscus lens satisfies 58 mm ≤ f1 ≤ 59 mm;

[0039] The focal length f2 of the second meniscus lens satisfies -80 mm ≤ f2 ≤ -79 mm;

[0040] The focal length f3 of the third meniscus lens satisfies 53 mm ≤ f3 ≤ 54 mm;

[0041] The focal length f4 of the fourth meniscus lens satisfies 38 mm ≤ f4 ≤ 39 mm;

[0042] The focal length f5 of the fifth meniscus lens satisfies -4109 mm ≤ f5 ≤ -4108 mm.

[0043] For the long-wave infrared spectral imaging lens provided by the present invention, the materials of the first meniscus lens, the third meniscus lens, and the fourth meniscus lens are germanium;

[0044] The materials of the second meniscus lens and the fifth meniscus lens are zinc sulfide;

[0045] For the long-wave infrared spectral imaging lens provided by the present invention, the integrated filter is a multi-channel integrated filter, which is used in combination with the spectral TDI technology to obtain a high-sensitivity spectral image.

[0046] The materials of the Dewar window and the integrated filter are germanium.

[0047] In the long-wave infrared spectral imaging lens provided by the present invention, the aperture stop can be set on the side of the lens closest to the object plane. Since the aperture stop has functions such as restricting the light beam and adjusting the light intensity, during the blackbody calibration process, the blackbody light entering the system can be more precisely controlled, thereby achieving high-precision radiation measurement calibration. On the other hand, in the solution of the present application, various lenses provided are set as meniscus lenses, which can significantly reduce spherical aberration and improve imaging quality. At the same time, through the combination of positive lenses and negative lenses, the incident light is transformed by convergence and divergence, so that the lens can have a better effect on converging or diverging the light beam, which can better improve the optical performance of the infrared spectral imaging lens, effectively reduce the aberration of the image, and further improve the imaging quality. In addition, by controlling the incident angle of the light, a real exit pupil is formed at the Dewar window, approximately achieving 100% matching of the cold aperture stop. Description of the Drawings

[0048] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0049] Figure 1It is a schematic diagram of the optical path of the long-wave infrared spectral imaging lens provided by an embodiment of the present invention;

[0050] Figure 2 It is a schematic diagram of the modulation transfer function of the long-wave infrared spectral imaging lens provided by an embodiment of the present invention;

[0051] Figure 3 It is a schematic diagram of the spot diagram of the long-wave infrared spectral imaging lens provided by an embodiment of the present invention;

[0052] Figure 4 It is a schematic diagram of the field curvature of the long-wave infrared spectral imaging lens provided by an embodiment of the present invention;

[0053] Figure 5 It is a schematic diagram of the distortion of the long-wave infrared spectral imaging lens provided by an embodiment of the present invention.

[0054] Wherein:

[0055] 1 - diaphragm; 2 - first meniscus lens; 3 - second meniscus lens; 4 - third meniscus lens;

[0056] 5 - fourth meniscus lens; 6 - fifth meniscus lens; 7 - Dewar window; 8 - integrated filter. Detailed implementation manners

[0057] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0058] Figure 1 It is a schematic diagram of the optical path of the long-wave infrared spectral imaging lens provided by an embodiment of the present invention.

[0059] As Figure 1 shown, this embodiment provides a long-wave infrared spectral imaging lens for long-wave infrared spectral imaging, which sequentially includes a diaphragm 1, a first meniscus lens 2, a second meniscus lens 3, a third meniscus lens 4, a fourth meniscus lens 5, a fifth meniscus lens 6, a Dewar window 7, and an integrated filter 8 arranged coaxially from the object plane to the image plane;

[0060] The first meniscus lens is a positive lens, the second meniscus lens is a negative lens, the third meniscus lens is a positive lens, the fourth meniscus lens is a positive lens, the fifth meniscus lens is a negative lens, and the Dewar window is a plano-convex lens;

[0061] The side of the first meniscus lens close to the object surface is an even aspherical surface, the side of the fourth meniscus lens close to the object surface is an even aspherical surface, and the second meniscus lens, the third meniscus lens, and the fifth meniscus lens are all spherical mirrors.

[0062] In the solution of this embodiment, an imaging optical path is formed by using five meniscus lenses. A meniscus lens refers to a lens with one convex outer surface and one concave inner surface. The meniscus lens can greatly reduce spherical aberration, and can obtain a smaller focal point and fewer aberrations than other types of lenses, so as to improve the imaging quality.

[0063] In practical applications, the Dewar window is equivalent to a cold stop when in use, which can limit the light beam, control the entry of light, and control the imaging range.

[0064] In addition, it should be noted that the diaphragm in the related art is generally placed behind the lens to better block the light outside the field of view from entering the system, thereby making the imaging quality better. However, in this way, the light before entering the system is not constrained, so it is not conducive to blackbody calibration, and the calibration effect will not be good enough. From this perspective, the final imaging effect will also be not good. In the solution of this embodiment, the position of the diaphragm is adjusted from behind the lens to in front of all the lenses, that is, when performing blackbody calibration, the light will first be restricted by the diaphragm, and high-precision radiation measurement calibration can be achieved. However, at the same time, due to the change in the position of the diaphragm, the lens cannot converge the light better. Based on this, in the solution of this embodiment, by controlling the type of lenses and the arrangement of positive and negative lenses in the original optical path, the lens can maintain or even improve the light converging effect from this perspective, and form a real exit pupil at the Dewar window. Furthermore, the imaging effect can be improved as a whole.

[0065] In an exemplary embodiment, the integrated filter is a multi-channel integrated filter, which is used in conjunction with the spectral TDI technology to obtain a high-sensitivity spectral image.

[0066] A filter is an optical element used to select light of a specific wavelength band. It can selectively transmit or reflect light of a specific wavelength through its optical properties. When light passes through the filter, due to the different refractive indices or propagation speeds of light of different wavelengths in the material, they will be separated into different spectral components, so as to achieve precise control and processing of light and perform spectral imaging. The integrated filter in this application is a multi-channel integrated filter, which is used in conjunction with the spectral TDI technology to obtain a high-sensitivity spectral image.

[0067] In an exemplary embodiment, the central thickness d1 of the first meniscus lens satisfies 14 mm ≤ d1 ≤ 18 mm;

[0068] The central thickness d2 of the second meniscus lens satisfies 5 mm ≤ d2 ≤ 10 mm;

[0069] The central thickness d3 of the third meniscus lens satisfies 5 mm ≤ d3 ≤ 10 mm;

[0070] The central thickness d4 of the fourth meniscus lens satisfies 4 mm ≤ d4 ≤ 8 mm;

[0071] The central thickness d5 of the fifth meniscus lens satisfies 5 mm ≤ d5 ≤ 10 mm.

[0072] Among them, the central thickness d1 of the first meniscus lens is preferably 16 mm; the central thickness d2 of the second meniscus lens is preferably 8 mm; the central thickness d3 of the third meniscus lens is preferably 8 mm; the central thickness d4 of the fourth meniscus lens is preferably 6 mm; the central thickness d5 of the fifth meniscus lens is preferably 8 mm.

[0073] In practical applications, the central thickness of the lens refers to the central thickness of the material at the central part of the lens, and measures the central thickness at the highest or lowest point of the two surfaces of the lens. In practical applications, by controlling the central thickness of the five lenses, the optical path length of the light passing through the lens can be accurately controlled. On the one hand, the optical path length here can affect the converging or diverging effect of the lens on the light, and on the other hand, it will also affect the energy loss of the light when propagating in the lens. Therefore, in this embodiment, by controlling the central thickness of the three lenses within a certain range, the relationship between the control effect of the lens on the light and the energy loss of the light can be balanced, so as to achieve the highest control effect with as little energy loss as possible.

[0074] In an exemplary embodiment, the distance p1 from the side of the first meniscus lens close to the object surface to the diaphragm satisfies 50 mm ≤ p1 ≤ 70 mm;

[0075] The distance p2 from the side of the second meniscus lens close to the object surface to the side of the first meniscus lens close to the image surface satisfies 20 mm ≤ p2 ≤ 30 mm;

[0076] The distance p3 from the side of the third meniscus lens close to the object surface to the side of the second meniscus lens close to the image surface satisfies 30 mm ≤ p3 ≤ 40 mm;

[0077] The distance p4 from the side of the fourth meniscus lens close to the object surface to the side of the third meniscus lens close to the image surface satisfies 80 mm ≤ p4 ≤ 90 mm;

[0078] The distance p5 from the side of the fifth meniscus lens close to the object surface to the side of the fourth meniscus lens close to the image surface satisfies 2 mm ≤ p5 ≤ 7 mm;

[0079] The distance p6 between the side of the Dewar near the object surface and the side of the fifth meniscus lens near the image surface satisfies 2 mm ≤ p5 ≤ 10 mm;

[0080] The distance p7 between the side of the integrated filter near the object surface and the side of the Dewar window near the image surface satisfies 30 mm ≤ p5 ≤ 40 mm;

[0081] The distance p8 between the image surface and the side of the Dewar window near the image surface satisfies 0 mm ≤ p5 ≤ 1 mm.

[0082] In implementation, the distances in this embodiment refer to vertical distances. In the solution of this embodiment, by controlling the vertical distances between the lenses, it can be ensured that the lenses exert the converging or diverging effects to the greatest extent, and problems such as excessive convergence, excessive divergence, insufficient convergence, or insufficient divergence can be avoided.

[0083] In an exemplary embodiment, the radius of curvature R1 of the side of the first meniscus lens near the object surface satisfies 80 mm ≤ R1 ≤ 90 mm;

[0084] The radius of curvature R2 of the side of the first meniscus lens near the image surface satisfies 150 mm ≤ R2 ≤ 160 mm;

[0085] The radius of curvature R3 of the side of the second meniscus lens near the object surface satisfies 24 mm ≤ R3 ≤ 27 mm;

[0086] The radius of curvature R4 of the side of the second meniscus lens near the image surface satisfies 15 mm ≤ R4 ≤ 20 mm;

[0087] The radius of curvature R5 of the side of the third meniscus lens near the object surface satisfies -60 mm ≤ R5 ≤ -50 mm;

[0088] The radius of curvature R6 of the side of the third meniscus lens near the image surface satisfies -50 mm ≤ R6 ≤ -40 mm;

[0089] The radius of curvature R7 of the side of the fourth meniscus lens near the object surface satisfies 50 mm ≤ R7 ≤ 60 mm;

[0090] The radius of curvature R8 of the side of the fourth meniscus lens near the image surface satisfies 90 mm ≤ R8 ≤ 100 mm;

[0091] The radius of curvature R9 of the side of the fifth meniscus lens near the object surface satisfies -160 mm ≤ R9 ≤ -150 mm;

[0092] The radius of curvature R10 of the side of the fifth meniscus lens near the image surface satisfies -135 mm ≤ R10 ≤ -130 mm;

[0093] Both the Dewar window and the integrated filter are planar.

[0094] In this embodiment, the radius of curvature of each surface of several lenses can also be defined. The radius of curvature is a quantity that describes the degree of curve bending change at a certain point on the curve. In this embodiment, while controlling the central thickness of the lens, the edge central thickness of the lens can also be controlled by defining the radius of curvature of the lens. On the one hand, the relationship between the control effect of the lens on the light passing through the edge and the energy loss of the light can be balanced. On the other hand, the radius of curvature can also control the aberration of the lens, and the obtained infrared lens can have a large image field with low distortion, thereby improving the imaging quality.

[0095] In an exemplary embodiment, the aspherical surface shapes on the object surface side of the first meniscus lens and the object surface side of the fourth meniscus lens conform to the following formula:

[0096]

[0097] where Z is the sagittal height, c is the curvature, r is the radial distance from a certain point on the lens to the optical axis, k is the conic coefficient, a 4 、a 6 and a 8 are all aspherical coefficients.

[0098] In an exemplary embodiment, the object surface side of the first meniscus lens satisfies:

[0099] a4 = 7.26E -8 , a6 = 4.36E -12 , a8 = 5.75E -15 , k = -1.37.

[0100] In an exemplary embodiment, the object surface side of the fourth meniscus lens satisfies:

[0101] a4 = 6.30E -6 , a6 = -5.80E -9 , a8 = 3.87E -12 , k = -8.71.

[0102] In an exemplary embodiment, the focal length f1 of the first meniscus lens satisfies 58 mm ≤ f1 ≤ 59 mm;

[0103] The focal length f2 of the second meniscus lens satisfies -80 mm ≤ f2 ≤ -79 mm;

[0104] The focal length f3 of the third meniscus lens satisfies 53 mm ≤ f3 ≤ 54 mm;

[0105] The focal length f4 of the fourth meniscus lens satisfies 38 mm ≤ f4 ≤ 39 mm;

[0106] The focal length f5 of the fifth meniscus lens satisfies -4109 mm ≤ f5 ≤ -4108 mm.

[0107] In practical applications, the focal length f1 of the first meniscus lens can be 58.705 mm; the focal length f2 of the second meniscus lens can be -79.806 mm; the focal length f3 of the third meniscus lens can be 53.943 mm; the focal length f4 of the fourth meniscus lens can be 38.883 mm; the focal length f5 of the fifth meniscus lens can be -4108.4 mm.

[0108] In an exemplary embodiment, the materials of the first meniscus lens, the third meniscus lens, and the fourth meniscus lens are germanium;

[0109] the materials of the second meniscus lens and the fifth meniscus lens are zinc sulfide;

[0110] The materials of the Dewar window and the integrated filter are germanium.

[0111] In practical applications, germanium and zinc sulfide have a high refractive index, which gives these two materials significant advantages and greater flexibility in optical design. Using germanium and zinc sulfide as the lens-making materials can make the prepared lens have a higher refractive index. On the one hand, it can reduce the distortion degree of the lens, and on the other hand, it can also reduce the sensitivity of the lens, making the performance of the lens more stable.

[0112] Table 1 below exemplifies the parameters such as the radius of curvature, thickness, and material of each optical device in the long-wave infrared spectral imaging lens provided by the solution of the present application.

[0113] Table 1

[0114]

[0115]

[0116] Among them, surface 1 in Table 1 above can be used to represent the aperture stop, surface 2 can be used to represent the object-side of the first meniscus lens, and surface 3 can be used to represent the image-side of the first meniscus lens; surface 4 can be used to represent the object-side of the second meniscus lens, surface 5 can be used to represent the image-side of the second meniscus lens; surface 6 can be used to represent the object-side of the third meniscus lens, surface 7 can be used to represent the image-side of the third meniscus lens; surface 8 can be used to represent the object-side of the fourth meniscus lens, surface 9 can be used to represent the image-side of the fourth meniscus lens; surface 10 can be used to represent the object-side of the fifth meniscus lens, surface 11 can be used to represent the image-side of the fifth meniscus lens; surface 12 can be used to represent the object-side of the Dewar window, surface 13 can be used to represent the image-side of the Dewar window; surface 14 can be used to represent the object-side of the filter, and surface 15 can be used to represent the image-side of the filter.

[0117] Correspondingly, the thickness of surface 1 can represent the thickness of the aperture stop; the thickness of surface 2 can represent the thickness of the first meniscus lens, and the thickness of surface 3 can represent the vertical distance from the image-side of the first meniscus lens to the object-side of the second meniscus lens; the thickness of surface 4 can represent the thickness of the second meniscus lens, and the thickness of surface 5 can represent the vertical distance from the image-side of the second meniscus lens to the object-side of the third meniscus lens; the thickness of surface 6 can represent the thickness of the third meniscus lens, and the thickness of surface 7 can represent the vertical distance from the image-side of the third meniscus lens to the object-side of the fourth meniscus lens; the thickness of surface 8 can represent the thickness of the fourth meniscus lens, and the thickness of surface 9 can represent the vertical distance from the image-side of the fourth meniscus lens to the object-side of the fifth meniscus lens; the thickness of surface 10 can represent the thickness of the fifth meniscus lens, and the thickness of surface 11 can represent the vertical distance from the image-side of the fifth meniscus lens to the object-side of the Dewar window meniscus lens; the thickness of surface 12 can represent the thickness of the Dewar window, and the thickness of surface 13 can represent the vertical distance from the image-side of the Dewar window to the object-side of the filter; the thickness of surface 14 can represent the thickness of the filter, and the thickness of surface 15 can represent the vertical distance from the image-side of the filter to the image plane.

[0118] In an exemplary embodiment, the long-wave infrared spectral imaging lens provided by the present application can be applied to a telescope, and the obtained telescope can operate in the long-wave infrared band of 8.0 μm to 12.5 μm, with a focal length of 60, an F-number of 2, a full field of view of 20°, and a distortion of less than 1%.

[0119] Figure 2 It is a schematic diagram of the curve of the modulation transfer function of the long-wave infrared spectral imaging lens provided by the embodiment of the present invention.

[0120] Figure 3 It is a schematic diagram of the spot diagram of the long-wave infrared spectral imaging lens provided by the embodiment of the present invention.

[0121] Figure 4 It is a schematic diagram of the field curvature of the long-wave infrared spectral imaging lens provided by the embodiment of the present invention.

[0122] Figure 5 It is a schematic diagram of the distortion of the long-wave infrared spectral imaging lens provided by the embodiment of the present invention.

[0123] As Figures 2 - 5 shown, the long-wave infrared spectral imaging lens disclosed in the present application can adopt a 640×512 detector, with a pixel center distance of 30μm. At the Nyquist frequency of 17lp / mm, the MTF of the full field of view is greater than 0.5, and the optical transfer function is close to the diffraction limit; the radius of the blur spot of the long-wave infrared spectral imaging lens is less than one pixel, less than 11.43μm; the system distortion is less than 1%, and the imaging quality is high.

[0124] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative labor.

[0125] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods of each embodiment or some parts of the embodiments.

[0126] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. Long-wave infrared spectral imaging lens, characterized in that: Used for long-wave infrared spectral imaging, from the object plane to the image plane, it includes an aperture arranged on the same optical axis, a first meniscus lens, a second meniscus lens, a third meniscus lens, a fourth meniscus lens and a fifth meniscus lens, a Dewar window, and an integrated filter; The first meniscus lens is a positive lens, the second meniscus lens is a negative lens, the third meniscus lens is a positive lens, the fourth meniscus lens is a positive lens, and the fifth meniscus lens is a negative lens; The side of the first meniscus lens close to the object plane is an even-order aspheric surface, the side of the fourth meniscus lens close to the object plane is an even-order aspheric surface, and the second meniscus lens, the third meniscus lens and the fifth meniscus lens are all spherical lenses; The center thickness d1 of the first meniscus lens satisfies 14 mm≤d1≤18 mm; The center thickness d2 of the second meniscus lens satisfies 5 mm≤d2≤10 mm; The central thickness d3 of the third meniscus lens satisfies 5 mm≤d3≤10 mm; The center thickness d4 of the fourth meniscus lens satisfies 4 mm≤d4≤8 mm; The central thickness d5 of the fifth meniscus lens satisfies 5 mm≤d5≤10 mm.

2. The long-wave infrared spectrum imaging lens according to claim 1, characterized in that: The distance p1 between the side of the first meniscus lens close to the object plane and the aperture satisfies 50 mm≤p1≤70 mm; A distance p2 between a side of the second meniscus lens close to the object plane and a side of the first meniscus lens close to the image plane satisfies 20 mm ≤ p2 ≤ 30 mm; A distance p3 between a side of the third meniscus lens close to the object plane and a side of the second meniscus lens close to the image plane satisfies 30 mm≤p3≤40 mm; A distance p4 between a side of the fourth meniscus lens close to the object plane and a side of the third meniscus lens close to the image plane satisfies 80 mm≤p4≤90 mm; A distance p5 between a side of the fifth meniscus lens close to the object plane and a side of the fourth meniscus lens close to the image plane satisfies 2 mm ≤ p5 ≤ 7 mm; The distance p6 between the side of the Dewar close to the object plane and the side of the fifth meniscus lens close to the image plane satisfies 2 mm≤p5≤10 mm; The distance p7 of the Dewar window close to the image plane from the side of the integrated filter close to the object plane satisfies 30 mm≤p5≤40 mm; The distance p8 between the image plane and the side of the Dewar window close to the image plane satisfies 0 mm≤p5≤1 mm.

3. The long-wave infrared spectral imaging lens according to claim 1, characterized in that: The curvature radius R1 of the first meniscus lens on the side close to the object plane satisfies 80 mm ≤ R1 ≤ 90 mm; The curvature radius R2 of the first meniscus lens on the side close to the image plane satisfies 150 mm≤R2≤160 mm; The curvature radius R3 of the second meniscus lens on the side close to the object plane satisfies 24 mm ≤ R3 ≤ 27 mm; The curvature radius R4 of the second meniscus lens on the side close to the image plane satisfies 15 mm ≤ R4 ≤ 20 mm; The radius of curvature R5 of the third meniscus lens on the side close to the object plane satisfies -60 mm ≤ R5 ≤ -50 mm; The radius of curvature R6 of the third meniscus lens on the side close to the image plane satisfies -50 mm ≤ R6 ≤ -40 mm; The radius of curvature R7 of the fourth meniscus lens on the side close to the object plane satisfies 50 mm ≤ R7 ≤ 60 mm; The curvature radius R8 of the fourth meniscus lens on the side close to the image plane satisfies 90 mm≤R8≤100 mm; The curvature radius R9 of the fifth meniscus lens on the side close to the object plane satisfies -160 mm ≤ R9 ≤ -150 mm; The curvature radius R10 of the fifth meniscus lens on the side close to the image plane satisfies -135 mm≤R10≤-130 mm.

4. The long-wave infrared spectrum imaging lens according to claim 1, characterized in that: The aspheric surface shapes of the first meniscus lens on the side close to the object surface and the fourth meniscus lens on the side close to the object surface conform to the following formula: Where Z is the vector height, c is the curvature, r is the radial distance from a point on the lens to the optical axis, k is the cone coefficient, and a4, a6 and a8 are all aspherical coefficients.

5. The long-wave infrared spectrum imaging lens according to claim 4, characterized in that: The side of the first meniscus lens close to the object plane satisfies: a4=7.26E -8 ,a6=4.36E -12 ,a8=5.75E -15 ,k=-1.

37.

6. The long-wave infrared spectrum imaging lens according to claim 4, characterized in that: The side of the fourth meniscus lens close to the object plane satisfies: a4=6.30E -6 ,a6=-5.80E -9 ,a8=3.87E -12 , k=-8.

71.

7. The long-wave infrared spectrum imaging lens according to claim 1, characterized in that: The focal length f1 of the first meniscus lens satisfies 58 mm≤f1≤59 mm; The focal length f2 of the second meniscus lens satisfies -80 mm ≤ f2 ≤ -79 mm; The focal length f3 of the third meniscus lens satisfies 53 mm≤f3≤54 mm; The focal length f4 of the fourth meniscus lens satisfies 38 mm≤f4≤39 mm; The focal length f5 of the fifth meniscus lens satisfies -4109 mm≤f5≤-4108 mm.

8. The long-wave infrared spectrum imaging lens according to claim 1, characterized in that: The material of the first meniscus lens, the third meniscus lens and the fourth meniscus lens is germanium; The second meniscus lens and the fifth meniscus lens are made of zinc sulfide.

9. The long-wave infrared spectrum imaging lens according to claim 1, characterized in that: The integrated filter is a multi-channel integrated filter, which cooperates with the spectral TDI technology to obtain a high-sensitivity spectral image.

Images