Semiconductor refrigerator and Dewar assembly

Abstract

The invention provides a semiconductor refrigerator and a Dewar assembly, and relates to the technical field of refrigeration infrared detectors, the semiconductor refrigerator comprises a cold end and a hot end, the cold end and the hot end are connected through a PN junction, and one side, away from the hot end, of the cold end is provided with at least one layer of solidified water vapor structure; the water vapor curing structure comprises a plurality of trapezoidal grooves extending towards the interior of the cold end, and a protrusion is formed between every two adjacent trapezoidal grooves. The beneficial effects are that water vapor can be induced to be solidified in advance at the installation position of the semiconductor cooler in the Dewar, and solidified water is trapped in the solidified water vapor structure and is prevented from escaping in the operation vibration process of the infrared detector, so that chip imaging is prevented from being interfered; the semiconductor refrigerator can work independently and conduct refrigeration in advance according to requirements, cooling capacity is provided independently, and the heat load of the chip refrigerator is reduced. In the getter activation process, heat can be prevented from being conducted to the chip through the ceramic lead ring and the supporting rod, and chip over-temperature failure is effectively avoided.

Description

Technical Field

[0001] The invention relates to the technical field of refrigerated infrared detectors, in particular to a semiconductor refrigerator and a Dewar assembly. Background Art

[0002] Refrigerated infrared detectors are widely used in precision-guided weapon systems, infrared thermal imaging, airborne infrared optoelectronic equipment, optoelectronic reconnaissance equipment, and other fields, and have become the mainstream of the market. In order to ensure the stability of the low-temperature working temperature of infrared detectors, it is necessary to ensure that they have long-term stable refrigeration performance. Based on this, the vacuum inside the dewar should be maintained at a constant level, and the vacuum life of the dewar has become a key indicator of infrared detectors.

[0003] During the packaging process, the infrared detector ensures the vacuum life by cleaning, baking, degassing and exhausting the components. After packaging, the getter inside the dewar continuously absorbs the gas released from the inner surface to ensure the vacuum life. In the design and use of the dewar, water vapor is one of the main reasons for the failure of the vacuum inside the dewar. Among them, the glue used to bond the components will release water vapor; hydrogen elements are precipitated inside the metal and combined with the surface oxygen elements to form water vapor. Water vapor will enhance the thermal convection between the inside and the outer shell of the dewar, causing the cooling rate of the cold head to slow down and the chip startup time to increase.

[0004] Conventional infrared detectors only have one cooling device and only cool a specific area. The presence of a large amount of water vapor may even condense into frost in the cooling area, reducing the imaging quality of the chip. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a semiconductor refrigerator, comprising a cold end and a hot end, wherein the cold end and the hot end are connected via a PN junction, and a side of the cold end away from the hot end is provided with at least one layer of solidified water vapor structure;

[0006] The solidified water vapor structure includes a plurality of trapezoidal grooves extending toward the interior of the cold end, and a protrusion is formed between two adjacent trapezoidal grooves.

[0007] Preferably, the upper bottom of the trapezoidal groove serves as the opening of the trapezoidal groove and is formed by laser rotary cutting and etching.

[0008] Preferably, the lower bottom of the trapezoidal groove serves as the opening of the trapezoidal groove, which is formed by etching the trapezoidal groove with the upper bottom as the opening on a ceramic substrate, and then turning the ceramic substrate and fixing it to the side of the cold end away from the hot end.

[0009] Preferably, the cold end and the hot end are arranged in a ring shape from inside to outside.

[0010] Preferably, the cold end and the hot end are made of hydrophilic insulating ceramics.

[0011] The present invention also provides a Dewar assembly, comprising the above-mentioned semiconductor refrigerator, including:

[0012] A main cylinder, wherein a cold head and a getter are arranged inside the main cylinder, the semiconductor refrigerator is circumferentially welded to the main cylinder and is located between the cold head and the getter, and the cold end is connected to the inside of the main cylinder;

[0013] A support rod, one end of which is connected to the cold end of the semiconductor refrigerator, and the other end of which is connected to the cold head.

[0014] Preferably, there are one or more semiconductor refrigerators.

[0015] Preferably, the support rod is made of metal material.

[0016] The present invention also provides a Dewar assembly, including the above-mentioned semiconductor refrigerator, including a window frame, a copper tube welded on the window frame, the semiconductor refrigerator is circumferentially welded to the window frame, the copper tube passes through the semiconductor refrigerator, and the cold end of the semiconductor refrigerator is connected to the inside of the window frame and faces the cold head.

[0017] The present invention also provides a Dewar assembly, comprising the semiconductor refrigerator described above, wherein the semiconductor refrigerator comprises at least one first refrigerator and at least one second refrigerator;

[0018] The first refrigerator is welded on the main cylinder and is located between the cold head and the getter, and the cold end of the first refrigerator is connected to the interior of the main cylinder;

[0019] The second refrigerator is welded to the window frame, and the cold end of the second refrigerator is connected to the inside of the window frame and faces the cold head.

[0020] The above technical solution has the following advantages or beneficial effects:

[0021] 1) It can induce water vapor to solidify in advance at the installation position of the semiconductor cooler inside the Dewar, and trap the solidified water inside the solidified water vapor structure to prevent it from escaping during the operation and vibration of the infrared detector, thereby preventing the chip imaging from being disturbed;

[0022] 2) The semiconductor refrigerator can work independently and perform cooling in advance according to demand, independently provide cooling capacity, and reduce the heat load of the chip refrigerator;

[0023] 3) During the activation process of the getter, it can prevent heat from being transmitted to the chip through the ceramic lead ring and the support rod, effectively preventing the chip from overheating and failing. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of a semiconductor refrigerator in a preferred embodiment of the present invention;

[0025] Figure 2 This is a schematic structural diagram of a preferred embodiment of the present invention, in which the upper base of the trapezoidal groove serves as the opening of the trapezoidal groove;

[0026] Figure 3 This is a schematic diagram of a preparation process flow when the lower bottom of the trapezoidal groove is used as the opening of the trapezoidal groove in a preferred embodiment of the present invention;

[0027] Figure 4 It is a schematic diagram of a structure including an incomplete trapezoidal groove in a preferred embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the process of solidifying water vapor in a solidifying water vapor structure in a preferred embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of cold end etching in a preferred embodiment of the present invention;

[0030] Figures 7 to 9 It is a structural schematic diagram of the Dewar assembly in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The present invention is not limited to this embodiment, and other embodiments may also fall within the scope of the present invention as long as they conform to the gist of the present invention.

[0032] In a preferred embodiment of the present invention, based on the above problems existing in the prior art, a semiconductor refrigerator is provided. Figures 1 to 3 As shown, it includes a cold end 1 and a hot end 2, the cold end 1 and the hot end 2 are connected via a PN junction 3, and a side of the cold end 1 facing away from the hot end 2 is provided with at least one layer of solidified water vapor structure;

[0033] The solidified water vapor structure comprises a plurality of trapezoidal grooves 11 extending toward the inside of the cold end 1 , and a protrusion 12 is formed between two adjacent trapezoidal grooves 11 .

[0034] Specifically, in this embodiment, the cold end 1 and the hot end 2 are made of hydrophilic insulating ceramics. The hydrophilic insulating ceramics are selected as the cold end 1 and the hot end 2 in order to more efficiently capture the water vapor in the vacuum chamber. In the actual preparation process, the above-mentioned solidified water vapor structure can be obtained by etching under the protection of helium by femtosecond laser, and the ceramic is ultrasonically cleaned after etching, and then the semiconductor refrigerator of the present invention is preferably welded and sealed together with the metal components of the Dewar assembly by brazing, where the metal components include but are not limited to the main cylinder and the window frame. After the welding and sealing is completed, the cold end 1 faces the inside of the Dewar, and the hot end 2 faces the outside of the Dewar.

[0035] The cold end 1 and the hot end 2 are arranged in a ring shape from the inside to the outside, so as to facilitate the shape of the metal component of the Dewar assembly, and at the same time, can provide circumferential refrigeration energy to the inside of the Dewar to improve the refrigeration effect.

[0036] Furthermore, the femtosecond laser etching process is a two-dimensional scanning process, wherein Figure 6 As shown, the X-axis rotates the annular semiconductor refrigerator by driving the rotating shaft 4, and the Y-axis swings back and forth through the scanning galvanometer 5 to achieve the etching of the above-mentioned solidified water vapor structure.

[0037] Furthermore, if Figure 2 As shown, the solidified water vapor structure is designed to be staggered with trapezoidal grooves 11 and corresponding protrusions 12, which can increase the surface area of ​​the cold end 1, accelerate the condensation of water vapor, and have a higher energy barrier, which can trap the condensed frost 6 therein. In other words, the condensed frost 6 needs to consume more energy to escape from the trapezoidal grooves 11. Based on this, when the semiconductor refrigerator of the present invention is installed on the Dewar assembly, a large amount of water vapor can be condensed during the chip cooling process, and the surface of the semiconductor refrigerator can independently provide cooling capacity, reducing the thermal load of the chip refrigerator. Specifically, Figure 5 As shown, after the semiconductor refrigerator is turned on, the cold end 1 can be cooled to about -50°C, and the water vapor molecules originally inside the Dewar begin to condense on the surface of the cold end 1 of the semiconductor refrigerator. During the condensation process, the water vapor molecules in the internal space of the Dewar gradually decrease until the surface of the cold end 1 is saturated with the condensation of water molecules.

[0038] In a preferred embodiment of the present invention, the upper bottom of the trapezoidal groove 11 is used as the opening of the trapezoidal groove 11 and is formed by laser rotary cutting. It can be understood that Figure 2 As shown, the solidified water vapor structure can be multi-layered and is not limited to Figure 2 The four layers shown can be obtained by laser etching layer by layer. The more layers there are, the better the condensation and solidification effect of water vapor.

[0039] In another preferred embodiment of the present invention, Figure 3As shown in FIG. 1 , the bottom of the trapezoidal groove 11 is used as the opening of the trapezoidal groove 11. It can be seen that the structure includes the barb 14 so that it cannot be obtained by direct laser etching. Based on this, the present invention is as follows Figure 3 As shown in (a), a trapezoidal groove 11 with an opening at the top bottom is etched on the ceramic substrate 13, and then Figure 3 (b) The ceramic substrate 13 is turned, and finally Figure 3 (c) is fixed to the side of the cold end 1 away from the hot end 2. The fixing methods here include but are not limited to bonding and brazing. It can be understood that Figure 3 As shown, the solidified water vapor structure can also be multi-layered and is not limited to Figure 3 In the actual preparation process, due to factors such as the different thicknesses of the selected ceramic substrate 13 and the different heights of the trapezoidal grooves 11, the last layer of trapezoidal grooves 11 etched may not be complete. Figure 4 shown.

[0040] The present invention also provides a Dewar assembly, comprising the above-mentioned semiconductor refrigerator, such as Figure 7 and Figure 8 As shown, including:

[0041] A main cylinder 100, a cold head 101 and a getter 102 are arranged inside the main cylinder 100, a semiconductor refrigerator is circumferentially welded on the main cylinder 100 and is located between the cold head 101 and the getter 102, and a cold end 1 is connected to the inside of the main cylinder 100;

[0042] A support rod 103 , one end of which is connected to the cold end 1 of the semiconductor refrigerator, and the other end of which is connected to the cold head 101 .

[0043] Specifically, in this embodiment, the above-mentioned Dewar assembly is a support rod direct-connected Dewar assembly, and the semiconductor refrigerator is preferably directly brazed to the main cylinder 100, and the end of the support rod 103 connected to the main cylinder 100 is instead bonded to the cold end 1. In this case, considering that the original ceramic support rod has good hardness, it is prone to brittle fracture during impact, especially when low-temperature cooling is used, the support rod 103 can be made of a metal material with better toughness instead of the original ceramic material.

[0044] In a preferred embodiment of the present invention, the semiconductor refrigerator is one or more, such as Figure 8 As shown, it is a two-stage refrigeration Dewar assembly, but it is not limited to two semiconductor refrigerators, and it can be multiple to form a multi-stage refrigeration Dewar assembly. It is only necessary to make the position of each semiconductor refrigerator between the cold head 101 and the getter 102. At the same time, the cold end 1 of the uppermost semiconductor refrigerator is connected to one end of the support rod 103. Among them, multiple semiconductor refrigerators are welded to the main cylinder 100 to provide coldness to the inside of the Dewar.

[0045] Since the packaging of the Dewar is not completed during the activation of the getter, and the temperature of the getter during activation can reach 600°C-1000°C, if a semiconductor refrigerator is not provided, the getter will transfer the heat generated during activation to the chip through the main tube and the support rod through thermal radiation and heat conduction, causing the chip to fail due to over-temperature. In the present invention, by providing a semiconductor refrigerator, it can work independently of the existing refrigeration device of the Dewar assembly. Based on this, the semiconductor refrigerator can be controlled to work first when the getter is activated, so that the semiconductor refrigerator close to the getter can play a role in blocking the heat conduction during activation, thereby enabling the semiconductor refrigerator close to the cold head to provide cooling to the chip under a higher temperature condition.

[0046] The present invention also provides a Dewar assembly, comprising the above-mentioned semiconductor refrigerator, such as Fig. 9 As shown, it includes a window frame 104 , a copper tube 105 is welded on the window frame 104 , a semiconductor refrigerator is circumferentially welded on the window frame 104 , the copper tube 105 passes through the semiconductor refrigerator, and the cold end 1 of the semiconductor refrigerator is connected to the inside of the window frame 104 and faces the cold head 101 .

[0047] Specifically, in this embodiment, when the semiconductor cooler is installed on the window frame 104, it is preferred to avoid the vent hole of the cold screen (through which the cold head is evacuated), and the installation position is not otherwise limited. The copper tube 105 can be welded to the window frame 104 together with the semiconductor cooler, or the semiconductor cooler can be welded first, and then a hole is opened in the semiconductor cooler to provide an installation space for the copper tube 105, which is not limited here.

[0048] Furthermore, the infrared detector needs to wait until the cold head is cooled to the working temperature before it can start to effectively detect infrared light, and the cold head cooling efficiency is mainly affected by the cooling efficiency of the refrigeration device, the heat conduction of the support rod, the cold head-shell thermal convection intensity, and the cold head-shell thermal radiation. Among them, installing the semiconductor refrigerator on the window frame 104 can effectively reduce the cold head-shell thermal radiation, and then reduce the thermal radiation of the window frame to achieve non-contact cooling of the cold head. The semiconductor refrigerator here can work first, or it can work simultaneously with the existing refrigeration device of the Dewar assembly. Working first can protect the chip when it is not turned on and activated, and better achieve the effect of solidifying water vapor.

[0049] The present invention also provides a Dewar assembly, comprising the semiconductor refrigerator described above, wherein the semiconductor refrigerator comprises at least one first refrigerator and at least one second refrigerator;

[0050] The first refrigerator is welded on the main cylinder 100 and is located between the cold head 101 and the getter 102, and the cold end 1 of the first refrigerator is connected to the inside of the main cylinder 100;

[0051] The second refrigerator is welded to the window frame 104 , and the cold end 1 of the second refrigerator is connected to the inside of the window frame 104 and faces the cold head 101 .

[0052] Specifically, Figure 7 and Fig. 9 Combine or Figure 8 and Fig. 9 The combination can obtain the integrated refrigeration Dewar assembly in this embodiment, which is not shown separately. The first refrigerator can be controlled to work before the infrared detector is turned on according to needs, so as to realize chip protection when it is activated when it is not turned on, and the second refrigerator can be controlled to work when the infrared detector is turned on, so as to realize the rapid and efficient refrigeration of the chip after it is turned on.

[0053] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of this specification and illustrations should be included in the protection scope of the present invention.

Claims

1. A semiconductor refrigerator, characterized in that: It comprises a cold end and a hot end, wherein the cold end and the hot end are connected via a PN junction, and a side of the cold end facing away from the hot end is provided with at least one layer of solidified water vapor structure; The solidified water vapor structure includes a plurality of trapezoidal grooves extending toward the interior of the cold end, and a protrusion is formed between two adjacent trapezoidal grooves.

2. The semiconductor refrigerator according to claim 1, characterized in that: The upper bottom of the trapezoidal groove serves as the opening of the trapezoidal groove and is formed by laser rotary cutting and etching.

3. The semiconductor refrigerator according to claim 1, characterized in that: The lower bottom of the trapezoidal groove serves as the opening of the trapezoidal groove. The trapezoidal groove with the upper bottom as the opening is obtained by etching on a ceramic substrate, and then the ceramic substrate is turned and fixed to the side of the cold end away from the hot end.

4. The semiconductor refrigerator according to claim 1, characterized in that: The cold end and the hot end are arranged in a ring shape from inside to outside.

5. The semiconductor refrigerator according to claim 1, characterized in that: The cold end and the hot end are made of hydrophilic insulating ceramics.

6. A Dewar assembly, characterized in that: A semiconductor refrigerator according to any one of claims 1 to 5, comprising: A main cylinder, wherein a cold head and a getter are arranged inside the main cylinder, the semiconductor refrigerator is circumferentially welded to the main cylinder and is located between the cold head and the getter, and the cold end is connected to the inside of the main cylinder; A support rod, one end of which is connected to the cold end of the semiconductor refrigerator, and the other end of which is connected to the cold head.

7. The Dewar assembly according to claim 6, characterized in that: The number of the semiconductor refrigerator is one or more.

8. The Dewar assembly according to claim 6, characterized in that: The support rod is made of metal material.

9. A Dewar assembly, characterized in that: It comprises a semiconductor refrigerator as described in any one of claims 1 to 5, including a window frame, a copper tube is welded on the window frame, the semiconductor refrigerator is circumferentially welded to the window frame, the copper tube passes through the semiconductor refrigerator, and the cold end of the semiconductor refrigerator is connected to the inside of the window frame and faces the cold head.

10. A Dewar assembly, characterized in that: A semiconductor refrigerator comprising the semiconductor refrigerator as claimed in any one of claims 1 to 5, wherein the semiconductor refrigerator comprises at least one first refrigerator and at least one second refrigerator; The first refrigerator is welded on the main cylinder and is located between the cold head and the getter, and the cold end of the first refrigerator is connected to the interior of the main cylinder; The second refrigerator is welded to the window frame, and the cold end of the second refrigerator is connected to the inside of the window frame and faces the cold head.

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