A dual-band detector with a common dewar structure

Abstract

The present invention discloses a dual-band detector common dewar structure, the dewar includes a window, an upper cavity, a cold shield, a spectroscope, a spectroscope frame, fixing screws, a band one module, a band two module, a flexible cable, a connector, a cold platform, a lower cavity, a column shell and a cold finger. Two detector modules are respectively installed on the cold platform, the spectroscope is glued to the spectroscope frame, the frame after gluing is fixed on the cold platform by screws, and the cold shield is connected to the cold platform; the window is airtightly connected to the upper cavity, the lower cavity is airtightly connected to the column shell and the cold finger, the upper and lower cavities form a vacuum dewar, and the electrical signal is led out through a flexible cable connected to the detector. In this structure, the spectroscope is installed in the dewar, which greatly reduces its own radiation and improves the imaging effect of the detector. The structure is compact and low in cost, and is suitable for the compact integration of low-background dual-band large-scale focal plane detectors.

Description

Technical Field

[0001] The invention belongs to the field of low-temperature packaging of detectors, in particular to a Dewar structure suitable for packaging low-background dual-band detectors. Background Art

[0002] Refrigerated infrared detector components are widely used in aerospace and remote sensing imaging. Sufficient information is obtained by observing the same target with multi-band detectors. Usually, light is divided into different bands by the front optical system through a spectrometer, and then incident on the dewar packaged with detectors of different bands for imaging. There are two main problems. First, the spectrometer is in front of the dewar. Due to the limited resources of the entire system and the high temperature of the spectrometer, it will introduce its own radiation. Especially in low background conditions, the radiation of the target itself is already very weak. The front optical system's own radiation is mixed with the information of the observed target, which greatly affects the imaging efficiency and imaging effect. Second, detectors of different bands are packaged in different dewars, and each dewar needs to integrate a refrigerator, which not only increases the cost of the entire system, but also increases the weight and size of the system. In order to meet the requirements of low cost, high resolution, and high integration, it can be achieved by packaging two detector modules of different bands together with the spectrometer in a low-temperature dewar. Summary of the invention

[0003] The present invention aims to provide a dual-band detector common dewar structure, which can be used for compact integration of multiple detectors of different bands, and is particularly suitable for low-temperature and deep-cryogenic packaging and occasions with high requirements for detector imaging.

[0004] A dual-band detector common dewar structure includes a window, an upper cavity, a cold screen, a spectroscope, a spectroscope frame, fixing screws, a band one module, a band two module, a flexible cable, a connector, a cold platform, a lower cavity, a column shell and a cold finger. The cold platform is a three-fold plate structure, and the band one module and the band two module are respectively installed on the upper surface of both sides of the cold platform by epoxy glue or screw connection; the upper surface of the cold platform is flat, and the lower surface is polished to reduce the surface emissivity. The angle between the module installation planes on both sides is 90°±1°, and the selected material is kovar or molybdenum material with low expansion and high thermal conductivity. The band one module and the band two module are detectors of different bands; one end of the flexible cable is connected to the band one module and the band two module, and the other end is connected to the connector that is airtightly connected to the lower cavity; the spectroscope is glued to the spectroscope frame, and the fixing screw passes through the through hole on the spectroscope frame. The hole is installed on the threaded hole on the upper surface of the middle folding plate of the cold platform; the cold screen is connected to the cold screen mounting hole on the upper surface of the cold platform by fixing screws, the outer surface of the cold screen 3 is polished or plated with a high reflectivity coating to reduce the surface emissivity, and the inner surface is plated with a low reflectivity coating to absorb stray light; the cold end of the cold finger is connected to the lower surface of the middle folding plate of the cold platform by screwing, and the hot end is airtightly welded to the column shell; the window is airtightly welded to the lens barrel of the upper cavity; the lower cavity is airtightly connected to the column shell and the upper cavity respectively, and the inner surfaces of the upper cavity, the lower cavity and the column shell are polished or plated with a high reflectivity coating to reduce the surface emissivity.

[0005] A multi-band detector common dewar structure of the present invention has the following three characteristics: first, the structure is compact, and one dewar is used to package two detector modules of different bands, which saves space and cost compared with one detector module being packaged by one dewar; second, the structure installs the spectroscope inside the dewar, and a large amount of cold is directly provided to the spectroscope by the cold platform. Compared with being placed outside the dewar, the spectroscope will obtain an extremely low temperature, reducing the radiation of the spectroscope itself, and improving the imaging efficiency and imaging effect of the detector; third, the cold platform adopts a material with high thermal conductivity and low expansion rate, which matches the thermal expansion coefficient of the detector, and can reduce the thermal stress of the detector module while providing sufficient cold for the detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 A dual-band detector shared dewar structure.

[0007] Figure 2 A cross-sectional view of the common dewar structure of a dual-band detector.

[0008] Figure 3 Schematic diagram of the beam splitter frame, where (1) is a front view of the beam splitter frame and (2) is a top view of the beam splitter frame.

[0009] Figure 4Schematic diagram of the cold platform, where (1) is the front view of the cold platform and (2) is the top view of the cold platform.

[0010] 1 window, 2 upper cavity, 3 cold screen, 4 spectroscope, 5 spectroscope frame, 6 fixing screws, 7 band 1 module, 8 band 2 module, 9 flexible cable, 10 connector, 11 cold platform, 12 lower cavity, 13 column shell, 14 cold finger, 5-1 through hole, 11-1 threaded hole, 11-2 mounting hole DETAILED DESCRIPTION

[0011] A dual-band detector common dewar structure includes a window 1, an upper cavity 2, a cold shield 3, a spectroscope 4, a spectroscope frame 5, a fixing screw 6, a band one module 7, a band two module 8, a flexible cable 9, a connector 10, a cold platform 11, a lower cavity 12, a column shell 13 and a cold finger 14. The cold platform 11 is a three-fold plate structure, and the band one module 7 and the band two module 8 are respectively installed on the upper surfaces of both sides of the cold platform 11 by epoxy glue or screw connection; the upper surface of the cold platform 11 is flat, and the lower surface is polished to reduce the surface emissivity. The angle between the module installation planes on both sides is 90°±1°, and the selected material is a low-expansion and high-thermal-conductivity Kovar or molybdenum material. The band one module 7 and the band two module 8 are detectors of different bands. One end of the flexible cable 9 is connected to the band one module 7 and the band two module 8, and the other end is connected to the connector 10 connected to the lower cavity 12 in an airtight manner. The beam splitter 4 is bonded to the beam splitter frame 5 by epoxy glue. The beam splitter 4 is a semi-transparent and semi-reflective mirror. The size and shape of the beam splitter frame 5 that wraps the beam splitter match the size and shape of the beam splitter 4. The M3 fixing screw 6 passes through the through hole 5-1 on the beam splitter frame 5 and is installed on the threaded hole 11-1 on the upper surface of the middle folding plate of the cold platform 11. The torque of the fixing screw 6 is 20cN*M. The cold screen 3 is connected to the cold screen mounting hole 11-2 on the upper surface of the cold platform 11 by fixing screws. The outer surface of the cold screen 3 is polished or plated with a high reflectivity coating to reduce Low surface emissivity, the inner surface is coated with a low reflectivity coating to absorb stray light, the shape and size of the cold screen 3 match the cold platform, and the cold screen mounting surface is also a three-fold plate structure; the cold end of the cold finger 14 is connected to the lower surface of the middle folded plate of the cold platform 11 by screwing, and the hot end is air-tightly welded to the column shell 13; the window 1 is air-tightly welded to the lens barrel of the upper cavity 2; the lower cavity 12 is air-tightly connected to the column shell 13 and the upper cavity 2 respectively, and the inner surfaces of the upper cavity 2, the lower cavity 12, and the column shell 13 are polished or plated with a high reflectivity coating to reduce the surface emissivity.

Claims

1. A dual-band detector common dewar structure, comprising a window (1), an upper cavity (2), a cold shield (3), a spectroscope (4), a spectroscope frame (5), fixing screws (6), a band one module (7), a band two module (8), a flexible cable (9), a connector (10), a cold platform (11), a lower cavity (12), a column shell (13) and a cold finger (14), characterized in that: The cold platform (11) is a three-fold plate structure, and the band one module (7) and the band two module (8) are respectively installed on the upper surface of both sides of the cold platform (11) by epoxy glue or screw connection; one end of the flexible cable (9) is connected to the band one module (7) and the band two module (8), and the other end is connected to the connector (10) which is airtightly connected to the lower cavity (12); the spectroscope (4) is glued to the spectroscope frame (5), and the fixing screws (6) pass through the through holes (5-1) on the spectroscope frame (5) and are installed in The threaded hole (11-1) on the upper surface of the middle folding plate of the cold platform (11); the cold screen (3) is connected to the cold screen mounting hole (11-2) on the upper surface of the cold platform (11) by means of fixing screws; the cold end of the cold finger (14) is connected to the lower surface of the middle folding plate of the cold platform (11) by means of screw connection, and the hot end is airtightly welded to the column shell (13); the window (1) is airtightly welded to the lens barrel of the upper cavity (2); the lower cavity (12) is airtightly connected to the column shell (13) and the upper cavity (2) respectively; The upper surface of the cold platform (11) is flat, the lower surface is polished, the angle between the module installation planes on both sides is 90°±1°, and the material of the cold platform is Kovar or molybdenum.

2. The dual-band detector common dewar structure according to claim 1, characterized in that: The band one module (7) and the band two module (8) are detectors of different bands.

3. The dual-band detector common dewar structure according to claim 1 is characterized in that The outer surface of the cold shield (3) is polished or plated with a high reflectivity coating, and the inner surface is plated with a low reflectivity coating.

4. The dual-band detector shared dewar structure according to claim 1, characterized in that The inner surfaces of the upper cavity (2), the lower cavity (12), and the column shell (13) are all polished or plated with a coating having a high reflectivity.

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