CN212007546U - Coupling structure of infrared Dewar assembly window and low-temperature optical system - Google Patents
Coupling structure of infrared Dewar assembly window and low-temperature optical system Download PDFInfo
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- CN212007546U CN212007546U CN202020223085.0U CN202020223085U CN212007546U CN 212007546 U CN212007546 U CN 212007546U CN 202020223085 U CN202020223085 U CN 202020223085U CN 212007546 U CN212007546 U CN 212007546U
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Abstract
The patent discloses a coupling structure of infrared dewar subassembly window and low temperature optical system. The coupling structure of the infrared Dewar component window and the low-temperature optical system comprises a window cap inner container, a heat insulation corrugated pipe, a window mounting plate, an infrared window, a low-temperature optical system mounting frame and a heat coupling layer. The method introduces a method for realizing the low-temperature window of the infrared Dewar component into the low-temperature optical system of the infrared remote sensing instrument, realizes the coupling of the Dewar window and the low-temperature optical system through a novel coupling structure, and utilizes the cold energy of the low-temperature optical system to refrigerate and cool the Dewar window, thereby finally realizing the purpose of reducing the influence of the spontaneous radiation of the window on the background noise of the system. Meanwhile, the flexible heat insulation corrugated pipe structure added in the structure can effectively inhibit the conduction of cold energy of the low-temperature optical system to the Dewar direction and avoid the problem of installation over-positioning between the optical registration installation of the Dewar component and the thermal coupling installation of the window.
Description
Technical Field
The patent relates to an infrared detector Dewar component technology and a low-temperature optical technology, in particular to a coupling structure of an infrared Dewar component window and a low-temperature optical system for reducing background radiation of a detector and an implementation method.
Background
The refrigeration type infrared detector assembly is widely applied to the field of aerospace infrared, and the detection performance of the infrared sensor is an important technical index of the high-spatial-resolution infrared remote sensing instrument. With the wavelength expansion to long wave and the improvement of detection sensitivity, the infrared detector must work at a deep low temperature. In order to realize the detection of longer wave bands and weaker signals, an infrared remote sensing instrument generally needs to reduce the background noise of a system by reducing the characteristic level of the infrared radiation of the infrared remote sensing instrument, so that the signal-to-noise ratio of the instrument is improved, and the detection performance of the external remote sensing instrument is finally improved. In the development of infrared remote sensing instruments, particularly in the design of long-wave and very-long-wave infrared remote sensing instruments, because the infrared radiation characteristic signal of a detected target is weak, the background noise of the target is generally reduced by a low-temperature optical system, so that the weak infrared signal is detected. The spontaneous radiation of the object temperature is suppressed by refrigerating and cooling all parts in the optical system of the remote sensing instrument, so that the system has low background noise.
The dewar is used as a packaging form of the infrared detector, and the dewar provides mechanical protection and vacuum environment for the detector while providing optical, mechanical, electrical, thermal and other interfaces for the detector. In order to ensure the structural strength of the dewar, the dewar is generally made of metal materials. The infrared window of the dewar is hermetically welded on the dewar shell, and the working temperature of the infrared window is generally normal temperature or near room temperature. When the dewar assembly encapsulating the infrared detector is installed into the cryogenic optical system, the spontaneous emission of the room temperature operating dewar window will have an adverse effect on the cryogenic optical system background noise. In a low-temperature optical system, the influence of the spontaneous radiation of the optical window on the Dewar on the background noise of the infrared remote sensing instrument can be solved by a method of keeping the temperature of the Dewar optical window consistent with the working temperature of the low-temperature optical system. The most effective method is to thermally couple the Dewar window part with the cold optical system, and cool the window by the cold optical system to make the temperature of the window consistent with that of the cold optical system.
Two main problems exist in the refrigeration and cooling of a Dewar window by a low-temperature optical system of an infrared remote sensing instrument. The first problem is the influence of the dewar after the dewar window is thermally coupled with the low temperature optical system on the cooling of the low temperature optical system: the direct refrigeration and temperature reduction of the Dewar window through the low-temperature optical system can lead the cold quantity of the low-temperature optical system to be inevitably conducted to the room temperature Dewar direction through the metal shell of the Dewar. Because the Dewar shell is made of metal materials, the heat conduction resistance is small, the cold energy of the cold optical system is conducted to the Dewar, the cold energy is lost, the low-temperature optical system cannot be cooled normally, and the cold optical system cannot reach the expected working temperature. Therefore, it is required to suppress the loss of the cooling energy from the low-temperature optical system to the dewar as much as possible. The second problem is the over-positioning problem of the registration installation of the Dewar inner detector and the optical system and the thermal coupling installation of the Dewar window and the cold optical system: in the process of installing the Dewar and the cryogenic optical system, the Dewar component firstly needs to complete the optical registration installation operation with the optical path of the system, and the position relation between the Dewar and the optical path after the operation is completed does not change. If the window and the cold optical system are thermally coupled and mounted on the Dewar, the Dewar shell with the rigid structure inevitably has over-positioning influence on the optical registration mounting during the thermal coupling and mounting. In summary, in order to reduce the influence of the dewar window spontaneous radiation of the infrared detector in the low-temperature optical system on the background noise of the infrared remote sensing instrument, a coupling structure of the infrared dewar assembly window and the low-temperature optical system and an implementation method thereof are urgently needed.
Disclosure of Invention
The purpose of this patent is to provide an infrared dewar subassembly window and low temperature optical system's coupled structure, through increase flexible bellows structure in the dewar structure in this patent, can effectively restrain the conduction of low temperature optical system cold volume to the dewar and avoid the excessive location problem in dewar and the installation of low temperature optical system.
The structure of this patent is shown in figure 1, which includes: the window cap comprises a window cap inner container 1, a heat insulation corrugated pipe 2, a window mounting plate 3, an infrared window 4, a low-temperature optical system mounting frame 5 and a heat coupling layer 6.
The coupling structure of the infrared Dewar component window and the low-temperature optical system is shown in figure 1, a heat insulation corrugated pipe 2 is arranged outside a window cap liner 1, a corrugated pipe welding edge 2-2 at one end of the heat insulation corrugated pipe 2 is connected with a liner corrugated pipe welding edge 1-2 in a welding mode, and a corrugated pipe welding edge 2-2 at the other end of the heat insulation corrugated pipe is connected with a mounting plate welding edge 3-3 in a welding mode; the infrared window 4 is welded in a window mounting step 3-2 of the window mounting plate 3; the thermal coupling layer 6 is arranged between the window mounting plate 3 and the low-temperature optical system mounting frame 5.
The window cap liner 1 is a kovar liner, a titanium alloy liner or a stainless steel liner, is cylindrical and is prepared in a machining mode, the bottom of the window cap liner is a liner dewar welding edge 1-1, the diameter of the liner dewar welding edge is consistent with that of an adaptive dewar, the size of a liner corrugated pipe welding edge 1-2 above the liner dewar welding edge 1-1 is consistent with that of a corrugated pipe welding edge 2-2, and the top of the window cap liner is a liner supporting surface 1-3.
As shown in fig. 2, the heat insulation corrugated pipe 2 is made of stainless steel or titanium alloy with poor heat conductivity, and is cylindrical, the heat insulation corrugated pipe 2 is in clearance fit with the liner supporting surface 1-3, and the two ends of the heat insulation corrugated pipe are corrugated pipe welding edges 2-2.
The window mounting plate 3 is made of kovar, stainless steel or titanium alloy metal materials, the size of a mounting plate welding edge 3-3 on the outer side of the bottom surface of the window mounting plate is consistent with that of a corrugated pipe welding edge 2-2, a window mounting step 3-2 is arranged in the center of the front surface of the window mounting plate, and mounting plate mounting holes 3-1 are circumferentially arranged.
The infrared window 4 is made of zinc sulfide, germanium or sapphire infrared light-transmitting material.
The low-temperature optical system mounting frame 5 is made of aluminum alloy or copper high-heat-conductivity metal materials and is of a plate-shaped structure, mounting frame screw holes 5-1 are formed in the periphery of the low-temperature optical system mounting frame 5, a mounting frame light through hole 5-2 is formed in the middle of the low-temperature optical system mounting frame 5, and a low-temperature optical mounting surface 5-3 is arranged on the bottom surface of the low-temperature optical system mounting frame and is matched with.
The material of the thermal coupling layer 6 is a high-thermal-conductivity soft metal sheet such as indium, aluminum and copper.
The realization method of the coupling structure of the infrared Dewar component window and the low-temperature optical system comprises the following steps:
1. the infrared window 4 is arranged in the mounting step 3-2 of the cover plate window, and airtight mounting is realized through a glue joint or filler welding mode.
2. And (3) performing airtight welding on the corrugated pipe welding edge 2-2 and the liner corrugated pipe welding edge 1-2 by using welding modes such as laser welding, argon arc welding, electron beam welding and the like.
3. And (3) carrying out airtight welding on the welding edge 3-3 of the mounting plate and the welding edge 2-2 of the corrugated pipe at the other end by using welding modes such as laser welding, argon arc welding, electron beam welding and the like.
4. And (3) welding the welding edge 1-1 of the inner container Dewar with the Dewar in an airtight manner by using welding modes such as laser welding, argon arc welding and the like, and finishing the preparation of the Dewar component. During the dewar vacuum pumping process, the window mounting plate 3 is pressed on the liner supporting surface 1-3 by the atmospheric pressure.
5. The low-temperature optical mounting surface 5-3 of the low-temperature optical system mounting frame 5 and the low-temperature optical system can be fixed with the low-temperature optical system in an integrated processing, welding and screw mounting mode. After the infrared detector dewar and the whole machine complete the optical registration operation, the clearance fit between the low-temperature optical system mounting frame 5 and the window mounting plate 3 is ensured.
6. The thermal coupling layer 6 is clamped between the low-temperature optical system mounting frame 5 and the window mounting plate 3, the thermal coupling layer 6 is required not to shield a system light path when the clamping is noticed, the mounting plate mounting hole 3-1 and the low-temperature optical system mounting frame 5-1 are aligned and fixed through a screw, and finally the window mounting plate 3 is clamped with the thermal coupling layer 6 and is installed on the low-temperature optical system mounting frame 5 in an extruding mode. The liner supporting surface 1-3 in the dewar is not in mechanical contact with the window mounting plate 3 after the thermal coupling installation.
The advantage of this patent is:
1. the structure is reliable, and the operation is convenient;
2. the method can effectively inhibit the conduction of cold energy of the low-temperature optical system to the Dewar;
3. the problem of the installation over-positioning of optical registration installation and thermal coupling installation can be effectively solved.
Drawings
FIG. 1 is a schematic view of a low heat leakage mounting structure for a low temperature optical Dewar window;
in the figure:
1-inner container of window cap;
2-heat insulation corrugated pipe;
3-window mounting plate;
4-infrared window;
5-a low temperature optical system mounting rack;
5-1-mounting rack screw hole;
5-2-a mounting rack light through hole;
5-3-low temperature optical mounting surface;
6-thermal coupling layer;
FIG. 2 is a schematic view of the structure of the inner container of the window cap;
in the figure:
1-welding the edge of the liner dewar;
1-2-welding edges of the liner corrugated pipe;
1-3-liner supporting surface;
FIG. 3 is a schematic view of an insulating bellows;
in the figure:
2-bellows welding edge;
2-1-bellows;
FIG. 4 is a schematic view of a window mounting plate;
in the figure:
3-1-mounting plate mounting holes;
3-2, mounting a step on the window;
3-installing the welding edge of the plate;
3-4-liner guide step;
Detailed Description
The following detailed description is made with reference to the accompanying drawings, and a schematic diagram of a coupling structure of an infrared dewar assembly window and a cryogenic optical system in the patent is shown in fig. 1, an infrared long-wave detector is sealed in the dewar, wherein a working temperature of the detector is 60K, a working temperature of the dewar shell is 280K, and a working temperature of the cryogenic optical system is 150K, and a specific implementation method of the patent is as follows:
the window cap liner 1 is made of kovar and is cylindrical, and is prepared in a machining mode, the wall thickness of the cylinder is 1mm, the diameter of a Dewar welding edge 1-1 of the bottom liner is 40mm, the diameter of a liner corrugated pipe welding edge 1-2 is 54mm, the outer diameter of a liner supporting surface 1-3 is 38mm, and the length from the liner corrugated pipe welding edge 1-2 to the liner supporting surface 1-3 is 40 mm.
The heat insulation corrugated pipe 2 is made of stainless steel, is cylindrical, has the wall thickness of 0.1mm, and has the inner diameter of 41mm, the diameter of the two end faces of the heat insulation corrugated pipe 2, namely the corrugated pipe welding edges 2-2, of 54mm and the length of the corrugated pipe of 42 mm.
The window mounting plate 3 material be kovar, thickness 5mm, mounting panel welding limit 3-3 diameter be 54mm, window installation step 3-2 diameter 33mm, dark 3.5mm, mounting panel mounting hole 3-1 has been arranged around the window mounting plate 3, the aperture is 4.5mm, and quantity is 6, 6 hole evenly distributed are on the circle of diameter 60 mm.
The infrared window 4 is made of germanium, has the diameter of 32mm and the thickness of 3mm, and meets the requirement of infrared long-wave optical light transmission.
The low-temperature optical system mounting rack 5 is made of aluminum alloy, threaded holes of the mounting rack threaded holes 5-1 are M4, the number of the threaded holes is 6, the 6 threaded holes are uniformly distributed on a circle with the diameter of 60mm, the diameter of the mounting rack light through hole 5-2 in the middle of the low-temperature optical system mounting rack 5 is 35mm, and the low-temperature optical mounting surface 5-3 is provided with 2 through holes with the diameter of 4.5 mm.
The thermal coupling layer 6 is made of indium sheet with the thickness of 0.2 mm.
The implementation process of the implementation method of the infrared Dewar component low-temperature window is as follows:
1. and installing the infrared window 4 into the cover plate window installation step 3-2, and carrying out airtight welding in a low-temperature brazing mode.
2. The corrugated pipe 2 is nested and installed on the window cap liner 1, and the corrugated pipe welding edge 2-2 and the liner corrugated pipe welding edge 1-2 are subjected to airtight welding by laser welding.
3. And carrying out airtight welding on the corrugated pipe welding edge 2-2 at the other end and the mounting plate welding edge 3-3 of the window mounting plate 3 by using laser welding.
4. Carrying out airtight welding on the liner dewar welding edge 1-1 and a dewar by using laser welding, and finishing the preparation of the infrared dewar assembly; in the process of vacuumizing in Dewar preparation, the window mounting plate 3 is pressed on the liner supporting surface 1-3 by atmospheric pressure, the window cap liner 1 realizes supporting and fixing of the window mounting plate 3,
5. and (3) carrying out optical registration installation on the infrared detector Dewar and the low-temperature optical system, and then installing and fixing a low-temperature optical installation surface 5-3 of the low-temperature optical system installation rack 5 and the low-temperature optical system through screws, wherein after the installation is finished, the gap between the low-temperature optical system installation rack 5 and the window installation board 3 is 1.2 mm.
6. A thermal coupling layer 6 with the thickness of 0.2mm is padded between the low-temperature optical system mounting frame 5 and the window mounting plate 3, when the thermal coupling layer 6 is noticed to be padded, a system light path cannot be shielded, and the window mounting plate 3 is padded with the thermal coupling layer 6 in a clamping manner and is mounted on the low-temperature optical system mounting frame 5 in a squeezing manner through screws; after the thermal coupling installation, the liner supporting surface 1-3 in the Dewar forms a distance of about 1mm with the window mounting plate 3, and the liner supporting surface 1-3 is not in mechanical contact with the window mounting plate 3.
Claims (7)
1. The utility model provides an infrared dewar subassembly window and low temperature optical system's coupled structure, includes window cap inner bag (1), thermal-insulated bellows (2), window mounting panel (3), infrared window (4), low temperature optical system mounting bracket (5), thermal coupling layer (6), its characterized in that:
the outer part of the inner container (1) of the window cap is provided with a heat insulation corrugated pipe (2), the heat insulation corrugated pipe (2) is in clearance fit with the inner container supporting surface (1-3), a corrugated pipe welding edge (2-2) at one end of the window cap is connected with the inner container corrugated pipe welding edge (1-2) in a welding way, and a corrugated pipe welding edge (2-2) at the other end of the window cap is connected with an installation plate welding edge (3-3) in a welding way; the infrared window (4) is welded in a window mounting step (3-2) of the window mounting plate (3); and a heat coupling layer (6) is arranged between the window mounting plate (3) and the low-temperature optical system mounting rack (5).
2. The structure of claim 1, wherein the infrared dewar assembly window and cryogenic optical system coupling structure comprises: the window cap liner (1) is a kovar liner, a titanium alloy liner or a stainless steel liner, is cylindrical, has a liner dewar welding edge (1-1) at the bottom and has a diameter consistent with that of an adaptive dewar, and is provided with a liner corrugated pipe welding edge (1-2) above the liner dewar welding edge (1-1) and a liner supporting surface (1-3) at the top, and the size of the liner corrugated pipe welding edge (1-2) is consistent with that of the corrugated pipe welding edge (2-2).
3. The structure of claim 1, wherein the infrared dewar assembly window and cryogenic optical system coupling structure comprises: the heat insulation corrugated pipe (2) is made of stainless steel or titanium alloy, is cylindrical, and is provided with corrugated pipe welding edges (2-2) at two ends.
4. The structure of claim 1, wherein the infrared dewar assembly window and cryogenic optical system coupling structure comprises: the window mounting plate (3) is made of kovar, stainless steel or titanium alloy, the size of a mounting plate welding edge (3-3) on the outer side of the bottom surface of the window mounting plate is consistent with that of a corrugated pipe welding edge (2-2), a window mounting step (3-2) is arranged in the center of the front surface of the window mounting plate, and mounting plate mounting holes (3-1) are circumferentially arranged.
5. The structure of claim 1, wherein the infrared dewar assembly window and cryogenic optical system coupling structure comprises: the infrared window (4) is made of zinc sulfide, germanium or sapphire infrared light-transmitting material.
6. The structure of claim 1, wherein the infrared dewar assembly window and cryogenic optical system coupling structure comprises: the low-temperature optical system mounting rack (5) is made of aluminum alloy or copper and is of a plate-shaped structure, mounting rack screw holes (5-1) are formed in the periphery of the low-temperature optical system mounting rack (5), a mounting rack light through hole (5-2) is formed in the middle of the low-temperature optical system mounting rack (5), and the bottom surface of the low-temperature optical system mounting rack is a low-temperature optical mounting surface (5-3) and the mounting structure of the low-.
7. The structure of claim 1, wherein the infrared dewar assembly window and cryogenic optical system coupling structure comprises: the material of the thermal coupling layer (6) is indium, aluminum and copper metal sheets.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020223085.0U CN212007546U (en) | 2020-02-28 | 2020-02-28 | Coupling structure of infrared Dewar assembly window and low-temperature optical system |
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|---|---|---|---|
| CN202020223085.0U CN212007546U (en) | 2020-02-28 | 2020-02-28 | Coupling structure of infrared Dewar assembly window and low-temperature optical system |
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| CN212007546U true CN212007546U (en) | 2020-11-24 |
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