Split infrared detector assembly

Abstract

The split infrared detector assembly comprises a split pulse tube refrigerator compressor, a gas reservoir, a refrigerator cold finger part and a Dewar; the infrared detector is assembled on the Dewar cold head, and the refrigerating machine cold finger component is formed by welding a refrigerating machine cold finger and a refrigerating machine cold table. The refrigerator cold finger is used as the Dewar cold finger, and the Dewar cold head is directly packaged on the refrigerator cold finger part, so that the coupling process of the Dewar and the refrigerator is avoided, constraint terms in the structural design of the refrigerator cold table are reduced, the heat transfer area of the top of the refrigerator cold table is effectively increased, and the temperature reaching time of an infrared detector is shortened; the assembly structure is free of coupling heat leakage, the refrigerating capacity requirement and the refrigerating power requirement of the refrigerating machine are effectively reduced, and the cost of the infrared detector assembly based on the split pulse tube refrigerating machine is reduced.

Description

Technical Field

[0001] The present application relates to the field of infrared detection technology, and in particular to a split-type infrared detector assembly. Background Art

[0002] With the rapid development of infrared detection technology, infrared detectors are widely used in many fields. Due to its compact structure, stable operation, low vibration, low electromagnetic interference, long life, high reliability and other advantages, the application of split pulse tube refrigerators in infrared detector components is also gradually increasing.

[0003] The common assembly process of the infrared detector dewar and the split pulse tube refrigerator is the dewar plug-in coupling. After the refrigerator and the detector dewar are assembled separately, the cold finger of the split pulse tube refrigerator is inserted into the dewar cold finger. The top surface of the refrigerator cold table and the bottom surface of the dewar cold table are tightly fitted with the help of thermal grease or couplers to transfer cold. After multiple detector power-offs or refrigerator startups and shutdowns, the thermal grease between the dewar and the refrigerator may be irreversibly displaced after deformation, resulting in failure of the plug-in coupling and the inability of the infrared detector to reach the temperature. When coupling is performed using a coupler, the coupler will apply a certain amount of pressure to the bottom of the dewar cold table and the top surface of the refrigerator cold finger. In order to reduce the negative impact of the coupler's pressure on the imaging of the infrared detector, the cold head structure is usually designed for stress unloading, resulting in a complex dewar cold head structure.

[0004] There are multiple parts such as thermal grease or couplers, Dewar cold stage, etc. between the infrared detector chip and the cold finger and cold stage of the refrigerator. There are many heat conduction interfaces and large conduction thermal resistance. When plug-in coupling is used, there is conduction heat leakage in the thin walls of the cold finger and Dewar cold finger of the refrigerator, and the coupling heat leakage is large. When the split pulse tube refrigerator adopts the plug-in coupling design, the cooling capacity of the refrigerator is high and the infrared detector takes a long time to reach temperature.

[0005] In the assembly structure of the rotary Stirling refrigerator and the dewar, the dewar and the refrigerator share the same cold finger. The assembly process is to complete the infrared detector dewar assembly first, and then insert the refrigerator regenerator into the dewar cold finger for coupling. The overall step is to assemble the refrigerator on the basis of the infrared detector dewar structure. Since the refrigerator cold finger of the split pulse tube refrigerator is connected to the compressor and the gas reservoir through an inertia tube, the inertia tube material is copper, and the assembly process is brazing. The temperature required for the brazing process is higher than the tolerance temperature of the infrared detector. Therefore, the split pulse tube refrigerator cannot refer to the assembly process of the rotary Stirling refrigerator for dewar coupling.

[0006] The common assembly process of infrared detector dewar and split pulse tube refrigerator is dewar plug-in coupling. This coupling structure has the risk of coupling failure after multiple detector power-off or refrigerator startup and shutdown. When a coupler is used, the force on the cold head is increased, which can easily cause the cold head to fall off or detector imaging abnormalities. There are multiple parts and contact surfaces such as thermal grease and dewar cold table between the infrared detector chip and the refrigerator cold table. The conduction thermal resistance is large and the infrared detector takes a long time to cool down. There is coupling heat leakage between the cold finger of the refrigerator and the dewar coupling part, and the net demand for cooling capacity of the refrigerator is large. Summary of the invention

[0007] The purpose of the present application is to provide a split-type infrared detector assembly to enhance the reliability of the infrared detector assembly.

[0008] To this end, an embodiment of the present application provides a split infrared detector assembly, including: a refrigerator cold finger component and a dewar, wherein the refrigerator cold finger component and the dewar are connected; a dewar cold head is provided in the dewar, the dewar includes the dewar cold head, the dewar cold head includes an infrared detector, a cold aperture, and an electrical frame, providing an optical, mechanical, and electrical environment for the low-temperature operation of the infrared detector; the refrigerator cold finger component is welded by a refrigerator cold table and a refrigerator cold finger, and the dewar cold head and the split pulse tube refrigerator share the refrigerator cold finger component.

[0009] In a possible implementation, the material of the refrigerator cold stage includes: one of iron-nickel alloy, iron-cobalt-nickel alloy, molybdenum-copper alloy, sapphire, aluminum oxide, aluminum nitride, and silicon carbide.

[0010] In a possible implementation, the shape of the assembly surface between the refrigerator and the Dewar cold head includes one of a circular shape, a rectangular shape, and a special shape.

[0011] In a possible implementation, the dewar further includes: a dewar shell and a refrigerator flange, and the dewar shell and the refrigerator flange are welded or sealed with a rubber ring.

[0012] In a possible implementation, the Dewar further includes: a lead ring or an electrical plug-in, which is welded or bonded to the Dewar housing.

[0013] In a possible implementation, the split infrared detector assembly further includes a window seat component, and the window seat component is welded or sealed on the Dewar by a rubber ring.

[0014] In a possible implementation, the split infrared detector assembly further includes an infrared detector, and the infrared detector is packaged on the Dewar cold head.

[0015] The present application also provides a method for installing a split-type infrared detector assembly, the method comprising: directly packaging a Dewar cold head where the infrared detector is located on a cold finger component of a refrigerator.

[0016] According to the embodiment of the present application, a split infrared detector assembly is provided, including: a refrigerator cold finger component, a dewar, and a split pulse tube refrigerator cold finger component is connected to the dewar; a dewar cold head is arranged in the dewar, the dewar cold head includes an infrared detector and a cold diaphragm, and the refrigerator cold finger component is welded by a refrigerator cold table and a refrigerator cold finger. Since the dewar cold head and the refrigerator share the refrigerator cold finger component, and the assembly process is mostly brazing welding, there are fewer design constraints on the refrigerator cold table. The area, shape and structure of the refrigerator cold table can be changed according to actual needs, which can effectively increase the heat transfer area and shorten the infrared detector to temperature time; the bonding area is increased, the mechanical connection structure is diversified, and the bonding force of the dewar cold head is effectively enhanced, avoiding the risk of coupling failure after multiple detector power-off or refrigerator power-on and power-off when the assembly process of the infrared detector dewar and the split pulse tube refrigerator is a dewar plug-in coupling. Compared with the coupler, this assembly structure does not apply force to the infrared detector, the cold head is subjected to less force, and there is no problem of cold head falling off or abnormal detector imaging. Compared with the plug-in coupling, the assembly structure of the present application simplifies the interface between the refrigerator and the infrared detector, and does not have multiple parts and contact surfaces such as thermal grease and Dewar cold stage, so the conduction thermal resistance is effectively reduced and the cooling time of the infrared detector is shortened. There is no coupling interface between the cold finger component of the refrigerator and the Dewar, and the coupling heat leakage is small, which effectively reduces the demand for the cooling capacity of the refrigerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In addition, in the drawings, the same components are marked with the same reference numerals, and the drawings are not drawn according to the actual scale.

[0018] Figure 1 A schematic structural diagram of a split-type infrared detector assembly provided in an embodiment of the present application is shown.

[0019] Description of reference numerals:

[0020] 1. Split pulse tube refrigerator compressor and gas reservoir; 2. Dewar; 3. Dewar cold head; 4. Refrigerator cold table; 5. Refrigerator cold finger; 6. Dewar shell; 7. Refrigerator flange; 8. Lead ring; 9. Window seat component. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0022] Figure 1 A schematic structural diagram of a split-type infrared detector assembly provided in an embodiment of the present application is shown.

[0023] like Figure 1 As shown, an embodiment of the present application provides a split infrared detector assembly, including: a split pulse tube refrigerator compressor and a gas reservoir 1, a dewar 2, the split pulse tube refrigerator compressor and the gas reservoir 1 and the refrigerator cold finger component are connected by a pipeline; a dewar cold head 3 is arranged in the dewar 2, the dewar cold head 3 includes a refrigerator cold table 4 and a refrigerator cold finger 5, the refrigerator and the dewar 2 share the refrigerator cold finger component, the refrigerator cold table 4 and the refrigerator cold finger 5 are welded, the dewar cold head 3 and the split pulse tube refrigerator share the refrigerator cold finger component, that is, the dewar cold head is assembled on the refrigerator cold finger component, wherein the split pulse tube refrigerator is referred to as a refrigerator in the text, the refrigerator is composed of a refrigerator cold finger component and a gas reservoir compressor, the former and the latter are connected by a connecting pipe and an inertia crown, and are separated in physical space, so it is called a split refrigerator.

[0024] In the present application, since the Dewar cold head 3 is directly assembled on the refrigerator cold table 4, the structural design constraints of the refrigerator cold table 4 are relatively few, and the area, shape, and structure of the refrigerator cold table 4 can be changed according to actual needs, which effectively increases the heat transfer area on the top of the refrigerator cold table 4, shortens the infrared detector's temperature-up time, and enhances the adhesion of the Dewar cold head 3.

[0025] In some examples, structures such as reinforcing ribs, screw holes, pin holes, and stress unloading grooves are designed on the top of the refrigerator cold stage 4 to increase the structural functionality of the refrigerator cold stage 4.

[0026] In some examples, the material used for the refrigerator cold stage 4 is a material with low linear expansion coefficient and high thermal conductivity, such as ceramic material, metal material and other non-metallic materials. Specifically, the material of the refrigerator cold stage 4 includes: one of 4J29, 4J36, TC4, iron-nickel alloy, iron-cobalt-nickel alloy, molybdenum-copper alloy, sapphire, aluminum oxide, aluminum nitride, and silicon carbide, thereby reducing the low-temperature deformation of the refrigerator cold stage 4 and optimizing the low-temperature performance of the infrared detector.

[0027] It can be understood that the refrigerator cold stage 4 in the present application does not use common materials with high thermal conductivity and high linear expansion coefficient, such as copper.

[0028] In some examples, the shape of the assembly surface of the refrigerator table 4 and the Dewar cold head 3 includes a circular, rectangular, or special-shaped shape, and the refrigerator cold table 4 can be provided with reinforcing ribs, screw holes, pin holes, stress unloading grooves, and other structures.

[0029] In some examples, such as Figure 1 As shown, the Dewar 2 further includes: a Dewar shell 6 and a refrigerator flange 7, and the Dewar shell 6 and the refrigerator flange 7 are welded together, thereby achieving a stable connection between the Dewar shell 6 and the refrigerator flange 7.

[0030] In some examples, such as Figure 1 As shown, the dewar 2 also includes: a lead ring 8, which is welded to the dewar housing 6. In this application, the lead ring 8, which is an electrical lead-out component, is laser welded to the dewar housing 6, thereby achieving a stable connection between the lead ring 8 and the dewar housing 6.

[0031] In a possible implementation, the split infrared detector assembly further includes a window seat component 9 , and the window seat component 9 is welded on the Dewar 2 .

[0032] In a possible implementation, the split infrared detector Dewar cold head 3 further includes an infrared detector, and the infrared detector is bonded to the refrigerator cold stage 4 .

[0033] It can be understood that the present application uses a fixture to make the refrigerator cold finger 5 vertically upward to provide operating space for the infrared detector assembly and the welding of the metal parts of the Dewar 2. The fixture includes but is not limited to metal fixtures, automatic or semi-automatic translation stages or rotating stages, etc.

[0034] In order to ensure a clear assembly interface between the refrigerator and the infrared detector Dewar assembly, the infrared detector assembly coupling is performed after the split pulse tube refrigerator is assembled, similar to the plug-in coupling.

[0035] When encapsulating the infrared detector, a special fixture is used to fix the split pulse tube refrigerator on the assembly table. After the cold table is leveled by the leveling fixture, an optical microscope such as a tool microscope is used to assist in the assembly of the infrared detector to ensure assembly accuracy. The infrared detector is encapsulated in the Dewar assembly using rubber ring compression sealing or laser welding.

[0036] The present application also proposes a method for installing a split infrared detector assembly, which is as follows:

[0037] The Dewar cold head where the infrared detector is located is directly encapsulated on the cold finger component of the refrigerator. First, the cold finger 5 of the refrigerator and the cold stage 4 of the refrigerator are brazed and welded. The subsequent assembly process is the same as that of a conventional split refrigerator to complete the refrigerator manufacturing.

[0038] Then, the lead ring 8 of the electrical lead-out part is laser welded to the Dewar housing 6, and the joint between the Dewar housing 6 and the refrigerator flange 7 is welded. The cold finger 5 of the refrigerator is laid flat upwards by the fixing fixture, and the cold head parts of the infrared detector are assembled in sequence with the help of a microscope. The electrical leads are welded using a deep cavity welding machine, and the remaining cold head parts are assembled. Finally, the window seat part 9 is welded, and the fixing fixture is removed to complete the assembly exhaust.

[0039] In the present application, the infrared detector is directly mounted on the cold finger 5 of the refrigerator, and there is no coupling interface between the Dewar 2 and the refrigerator, which reduces coupling heat leakage and reduces the cooling demand of the split infrared detector assembly on the refrigerator. In addition, the infrared detector is directly mounted on the refrigerator cold stage 4, which reduces the interfaces such as the Dewar 2 cold stage and the coupling medium, reduces the conduction thermal resistance, and shortens the time for the assembly to reach temperature. In addition, the present application directly couples the infrared detector cold head component to the refrigerator cold stage 4, avoiding plug-in coupling and improving the reliability of the assembly. The assembly process provided in the present application avoids applying force to the bottom of the Dewar cold head 3 when coupling the Dewar 2 with the refrigerator, improves the reliability of the cold head structure, does not require stress unloading and other designs, and does not have a negative impact on the imaging of the infrared detector.

[0040] It should be noted that the embodiments represented by "one embodiment", "an embodiment", "an exemplary embodiment", "some embodiments", etc. mentioned in the specification may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when describing specific features, structures or characteristics in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such features, structures or characteristics in conjunction with other embodiments that are explicitly or not explicitly described.

[0041] It should be easily understood that “on,” “above,” and “over” in the present disclosure should be interpreted in the broadest manner, so that “on” not only means “directly on something,” but also includes the meaning of “on something” with intervening features or layers therebetween, and “above” or “over” not only includes the meaning of “above” or “over,” but also may include the meaning of “above” or “over something” with no intervening features or layers therebetween (i.e., directly on something).

[0042] In addition, spatially relative terms, such as "below," "below," "beneath," "above," "above," etc., may be used herein for ease of description to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. The device may have other orientations (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein may likewise be interpreted accordingly.

[0043] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A split infrared detector assembly, characterized in that: include: A refrigerator cold finger component and a dewar, wherein the refrigerator cold finger component is connected to the dewar; The dewar comprises a dewar cold head, which comprises an infrared detector, a cold aperture, and an electrical frame, and provides an optical, mechanical, and electrical environment for the infrared detector to work at low temperature; The refrigerator cold finger component is formed by welding the refrigerator cold stage and the refrigerator cold finger, and the Dewar cold head and the split pulse tube refrigerator share the refrigerator cold finger component.

2. The split infrared detector assembly according to claim 1, characterized in that: The material of the refrigerator cold stage includes: one of iron-nickel alloy, iron-cobalt-nickel alloy, molybdenum-copper alloy, sapphire, aluminum oxide, aluminum nitride, and silicon carbide.

3. The split infrared detector assembly according to claim 1, characterized in that: The shapes of the assembly surfaces of the refrigerator and the Dewar cold head include circular, rectangular and special shapes.

4. The split infrared detector assembly according to claim 1, characterized in that: The dewar further comprises: a dewar shell and a refrigerator flange, and the dewar shell and the refrigerator flange are connected by welding or rubber ring sealing.

5. The split infrared detector assembly according to claim 4, characterized in that: The dewar further comprises: a lead ring or an electrical plug-in, and the lead ring or the electrical plug-in is welded on the dewar housing.

6. The split infrared detector assembly according to claim 5, characterized in that: The split infrared detector also includes a window seat component, and the window seat component is connected to the Dewar in the form of welding or rubber ring sealing.

7. The split infrared detector assembly according to claim 1, characterized in that: The infrared detector is packaged above the cold finger component of the refrigerator.

8. A method for installing a split infrared detector assembly, characterized in that: The method comprises: directly packaging a Dewar cold head where the infrared detector is located on a cold finger component of a refrigerator.

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