An irregularly shaped cold shield suitable for cryogenic refrigerators

Abstract

The application belongs to the technical field of mechanical manufacturing, and discloses a special-shaped cold screen suitable for a low-temperature refrigerator, which comprises an outer cover, a filter is arranged on the top of the outer cover, a cold head is arranged in the inner cavity of the outer cover, a special-shaped cold screen body and a sensor chip are fixedly installed on the top surface of the cold head, a vacuum cover is arranged at the lower end of the outer cover, an air extraction interface is arranged at the lower end of the vacuum cover, and a flange and a lead ring are fixedly installed in sequence at the upper end of the outer wall of the outer cover. Through cooperation of the cold head, the sensor chip and other structures, the special-shaped cold screen is directly fixed on the cold head of the low-temperature refrigerator, part of cold energy is conducted to the special-shaped cold screen through heat transfer, the temperature of the special-shaped cold screen is reduced, the signal interference of thermal radiation on the sensor chip is reduced, the black body on the inner surface of the shell absorbs stray radiation energy reflected from the surface of the sensor chip, and the influence of stray radiation energy on the signal of the sensor chip is reduced.

Description

Technical Field

[0001] This invention belongs to the field of mechanical manufacturing technology, specifically a non-circular cold shield suitable for cryogenic refrigeration machines. Background Technology

[0002] Sensor chips that undergo photoelectric reactions under irradiation require a special working environment. The cold head of the refrigerator cools the sensor chip, while the Dewar assembly provides a vacuum environment and the electrical connections needed for signal transmission. Therefore, the performance of the sensor chip is determined by its own performance, the matching design of the Dewar structure, and the cooling temperature. The manufacturing process of sensor chips is complex, and improvements to their performance are increasingly limited. However, with relatively stable cooling temperatures, it is necessary to explore the optimization and improvement potential of the Dewar assembly. The Dewar assembly consists of a window, a shell, a lead ring, and a cold shield. The cold shield is mounted on the cold head, and the sensor chip is placed inside. An opening at the top allows irradiated energy to enter. The cold shield provides a stable cold environment for the sensor chip and is also a crucial component for eliminating stray radiation within the Dewar assembly. Due to the special function and structural variability of the cold shield, improvements and optimizations to it will greatly enhance the insulation and shielding performance of the Dewar.

[0003] When developing and designing a new type of sensor chip, it is necessary to manufacture a matching Dewar assembly to provide the corresponding low temperature and vacuum environment. However, the Dewar assembly used in actual engineering is a complex and expensive special device. In order to facilitate continuous correction and adjustment during the early stage of sensor chip development, it is necessary to manufacture a Dewar assembly that can disassemble and replace the sensor chip in a timely manner, so as to reduce manufacturing costs, shorten the experimental testing cycle of the sensor chip, and improve the development efficiency of the sensor chip.

[0004] The commonly used Dewar structure is too complex and is generally used for packaging pre-shaped Dewar components. The simplified Dewar component removes the central core and the elastic cold chain used to transfer cold energy, integrating the sensor chip, the refrigerator and the Dewar component into one unit. The sensor chip is directly mounted on the cold head of the refrigerator with low-temperature adhesive, and the cold shield is also fixed to the cold head with screws. The structure of the cold shield is constrained by the cold head of the refrigerator, the Dewar component and the sensor chip. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention provides an irregularly shaped cold shield suitable for cryogenic refrigerators.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an irregularly shaped cold shield suitable for cryogenic refrigerators, comprising an outer cover, a filter provided on the top of the outer cover, a cold head provided in the inner cavity of the outer cover, an irregularly shaped cold shield body and a sensor chip fixedly mounted on the top surface of the cold head, a vacuum cover provided at the lower end of the outer side of the outer cover, an air extraction port provided at the lower end of the vacuum cover, and a flange and a lead ring fixedly mounted sequentially on the upper end of the outer wall of the outer cover.

[0007] Preferably, the surface of the cold head is provided with a support foot, which is connected to the cold head through screw holes, and the side of the support foot is arc-shaped.

[0008] Preferably, the sensor chip is fixedly connected to the top of the cold head, and the cold head is in the shape of a "T".

[0009] Preferably, there are two legs, and a housing is fixedly installed between the two legs. The top surface of the housing is provided with a top cover, and the side of the housing is provided with a side opening.

[0010] Preferably, the inner cavity of the housing is provided with an inner surface, the outer side of the housing is provided with an outer surface, and the inner surface is directly manufactured by wire cutting.

[0011] Preferably, the top cover is made of thin-walled stainless steel plate, and a light-transmitting hole is provided in the middle of the top cover, and the light-transmitting hole is circular.

[0012] Preferably, the vacuum hood and the air extraction port are connected, and a movable plug is provided at the end of the air extraction port away from the vacuum hood.

[0013] Preferably, the length of the top cover is the same as the length of the top of the inner surface of the housing, and the top cover and the housing are on the same horizontal plane.

[0014] Preferably, a protrusion is provided at the upper end of the inner cavity of the outer cover, and the surface of the protrusion is smooth, and the filter is disposed on the top surface of the protrusion.

[0015] Preferably, the inner cavity of the lead ring is provided with rubber blocks, and several of them are arranged in a ring at equal intervals.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] This invention, through the combination of a cold head and a sensor chip, allows an irregularly shaped cold screen to be directly fixed to the cold head of a cryogenic refrigerator. This enables some of the cooling energy to be transferred to the irregularly shaped cold screen through heat transfer, greatly reducing the temperature of the cold screen itself and minimizing the signal interference of thermal radiation on the sensor chip.

[0018] This invention, through the coordination of the inner surface of the housing and the sensor chip, etc., after the interior of the irregularly shaped cold screen is blackened, the black body on the inner surface of the housing absorbs the stray radiation energy reflected from the surface of the sensor chip, thereby reducing the impact of stray radiation energy on the sensor chip signal.

[0019] This invention polishes and grinds the outer surface of the irregularly shaped cold screen by setting up structures such as the outer surface of the shell, forming a mirror-like reflective effect and reducing the loss of cold energy inside the cold screen caused by the heat radiation inside the Dewar. Attached Figure Description

[0020] Figure 1 This is a frontal cross-sectional view of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure at the light-transmitting hole of the present invention;

[0023] Figure 4 This is a schematic diagram of the inner surface structure of the housing of the present invention.

[0024] In the diagram: 1. Filter; 2. Outer cover; 3. Irregularly shaped cold shield body; 4. Flange; 5. Lead ring; 6. Sensor chip; 7. Cold head; 8. Vacuum cover; 9. Evacuation port; 10. Top cover; 11. Housing; 12. Light transmission hole; 13. Inner surface of housing; 14. Outer surface of housing; 15. Support leg; 16. Screw hole; 17. Side opening. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figures 1 to 4 As shown, the present invention provides an irregularly shaped cold shield suitable for cryogenic refrigerators, including an outer cover 2, a filter 1 on the top of the outer cover 2, a cold head 7 in the inner cavity of the outer cover 2, an irregularly shaped cold shield body 3 and a sensor chip 6 fixedly installed on the top surface of the cold head 7, a vacuum cover 8 at the lower end of the outer side of the outer cover 2, an air extraction port 9 at the lower end of the vacuum cover 8, and a flange 4 and a lead ring 5 fixedly installed sequentially on the upper end of the outer wall of the outer cover 2.

[0027] The above scheme is adopted as follows: Through the design of the irregularly shaped cold screen body 3 and the sensor chip 6, the sensor chip 6 is installed inside the irregularly shaped cold screen body 3. The external wiring of the sensor chip 6 is connected to the lead ring 5 located between the flange 4 and the vacuum chamber 8 through the side opening 17 of the irregularly shaped cold screen. Light shines on the sensor chip 6 through the filter 1 and the light-transmitting hole 12 at the top of the irregularly shaped cold screen. The sensor chip 6 is fixed to the cold head 7 with low-temperature adhesive. The Dewar assembly seals the irregularly shaped cold screen body 3, the sensor chip 6 and the cold head 7 in a vacuum environment. The upper part of the Dewar assembly is a detachable outer cover 2. The filter 1 is fixed to the surface of the outer cover 2 with low-temperature adhesive. The flange 4, the lead ring 5 and the vacuum chamber 8 are all welded.

[0028] like Figure 1 , Figure 2 As shown, the surface of the cold head 7 is provided with a support foot 15, which is connected to the cold head 7 through a screw hole 16. The side of the support foot 15 is arc-shaped. The sensor chip 6 is fixedly connected to the top of the cold head 7, and the cold head 7 is in the shape of a "T".

[0029] The above solution is adopted as follows: Through the cooperation of the cold head 7 and the support leg 15, the irregularly shaped cold screen is fixed to the end face of the cold head 7 by screws passing through the screw holes 16 on the support leg 15, thereby fixing the support leg 15. The arc design of the support leg 15 makes the support leg 15 more aesthetically pleasing when viewed. Through the design of the sensor chip 6 and the cold head 7, the sensor chip 6 is fixedly connected to the top of the cold head 7 and located in the inner cavity of the irregularly shaped cold screen body 3, thereby fixing the sensor chip 6 and preventing the sensor chip 6 from shaking during the use of the irregularly shaped screen, which could lead to damage to the device. The "T"-shaped design of the cold head 7 can better fix and install the sensor chip 6 and the irregularly shaped cold screen body 3, increasing the installation area on the top surface of the cold head 7.

[0030] like Figure 2 , Figure 4 As shown, there are two legs 15, and a housing 11 is fixedly installed between the two legs 15. A top cover 10 is provided on the top surface of the housing 11. A side opening 17 is provided on the side of the housing 11. An inner surface 13 is provided in the inner cavity of the housing 11. An outer surface 14 is provided on the outer side of the housing 11. The inner surface 13 is made directly by wire cutting.

[0031] The above solution is adopted: Through the design of the support legs 15 and the housing 11, the housing 11 is fixedly installed using two support legs 15. The irregularly shaped cold screen is assembled and welded from the pre-made upper cover 10 and the housing 11. The upper cover 10 is made of a thin-walled stainless steel plate of approximately 0.2mm. First, the four sides of the upper cover 10 are smoothed so that the upper end face of the upper cover 10 is on the same plane as the upper end face of the housing 11. Then, a laser welding machine is used to align the connection lines of the upper cover 10 and the housing 11 for laser welding, making them integrated. After welding, the weld seam is smoothed using tools. The housing 11 has a square structure with a wall thickness of approximately 0.2mm. The two support legs 15 are located on the bottom surface, symmetrically arranged on both sides, with two screw holes 16 for fixing. The remaining... The lower ends of the two sides are removed to create two rectangular side openings 17. The irregularly shaped cold screen body 3 is assembled and welded using the prepared top cover 10 and shell 11. Through the design of the inner surface 13 and outer surface 14 of the shell, the irregularly shaped cold screen welded together is blackened using special equipment, so that the inner surface 13 and outer surface 14 of the irregularly shaped shell become approximately black bodies. Then, without damaging the black body of the inner surface 13 of the shell, the outer surface, including the perimeter of the shell 11 and the upper end of the top cover 10, is polished until the outer surface 14 of the irregularly shaped cold screen reaches a near-mirror finish. The inner surface 13 of the shell is directly made by wire cutting, which achieves the goal of reducing the structural deformation of the irregularly shaped cold screen while ensuring thin walls.

[0032] like Figure 2 , Figure 3 and Figure 4 As shown, the upper cover 10 is made of thin-walled stainless steel plate. A light-transmitting hole 12 is provided in the middle of the upper cover 10, and the light-transmitting hole 12 is circular. The length of the upper cover 10 is the same as the length of the top of the inner surface 13 of the shell, and the upper cover 10 and the shell 11 are on the same horizontal plane.

[0033] The above-mentioned design, through the design of the top cover 10 and the light-transmitting hole 12, allows the thin-walled stainless steel to be relatively lightweight, facilitating transportation and installation. It also possesses excellent corrosion resistance, resisting the erosion of various chemical media, and performs exceptionally well in humid and acidic / alkaline environments, extending its service life. The thin-walled stainless steel still maintains high strength and rigidity, capable of withstanding significant loads and resisting deformation. Furthermore, it exhibits good high-temperature resistance, maintaining good stability in high-temperature environments. The circular design of the light-transmitting hole 12 ensures more uniform light transmission, and the uniform edge of the circular hole contributes to superior mechanical properties, reducing the likelihood of light scattering. Stress concentration or deformation in materials, circular holes are usually simple and symmetrical in design, which can enhance the aesthetics of the overall appearance. By matching the top cover 10 and the inner surface 13 of the housing, the top surface of the top cover 10 and the top of the inner surface 13 of the housing have the same length value, so that the top cover 10 can be installed. Then, the four sides of the top cover 10 are smoothed and inserted into the inner surface 13 of the housing 11, so that the upper end face of the top cover 10 and the upper end face of the housing 11 are on the same plane. Then, a laser welding machine is used to align the connection line of the top cover 10 and the housing 11 and perform laser welding to make the two join together. After the welding is completed, the weld seam is smoothed with tools.

[0034] like Figure 1 , Figure 4 As shown, the vacuum hood 8 and the air extraction port 9 are connected. The end of the air extraction port 9 away from the vacuum hood 8 is provided with a movable plug. The upper end of the inner cavity of the outer cover 2 is provided with a protrusion, and the surface of the protrusion is smooth. The filter 1 is provided on the top surface of the protrusion. The inner cavity of the lead ring 5 is provided with rubber blocks, and several of them are arranged in a ring at equal intervals.

[0035] The above scheme employs the following design: The vacuum chamber 8 and the extraction port 9 are connected, allowing for better vacuuming. The movable plug design of the extraction port 9 ensures that after vacuuming, the port is blocked to prevent air from re-entering. The outer cover 2 and the filter 1 work together; the upper protrusion of the outer cover 2 facilitates the installation of the filter 1, making it more stable. The top surface of the filter 1 and the outer cover 2 are at the same horizontal level. The smooth surface of the protrusion reduces friction with the filter 1, preventing damage. The inner surface 13 of the housing and the... The design of the lead ring 5, with the inner surface 13 and outer surface 14 of the housing approximating a blackbody, helps to provide a stable and uniform radiation source, facilitating high-precision measurement and calibration. It can effectively block or isolate the influence of other heat sources, keeping the environment stable and reducing unnecessary radiation interference. At the same time, it can effectively disperse or absorb heat in the equipment, improving the working efficiency of the cooling system. The design of the lead ring 5 rubber block increases the friction with the external wiring of the sensor chip 6, thereby achieving the effect of fixing the wire. The multiple design makes it less likely for the connecting wires to tangle when there are many wires.

[0036] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A profiled cold screen suitable for use in a cryogenic refrigerator comprising an outer shell (2) characterised in that: The top of the cover (2) is provided with a filter (1), the inner cavity of the cover (2) is provided with a cold head (7), the top surface of the cold head (7) is fixedly installed with a special-shaped cold screen body (3) and a sensor chip (6), the lower end of the outer side of the cover (2) is provided with a vacuum cover (8), the lower end of the vacuum cover (8) is provided with a gas extraction interface (9), the upper end of the outer wall of the cover (2) is sequentially fixedly installed with a flange (4) and a lead ring (5), the surface of the cold head (7) is provided with a supporting leg (15), the supporting leg (15) is connected with the cold head (7) through a screw hole (16), and the side edge of the supporting leg (15) is arc-shaped.

2. A profiled cold screen for a cryogenic refrigerator according to claim 1, characterized in that: The sensor chip (6) is fixedly connected with the top of the cold head (7), and the cold head (7) is in the shape of "T".

3. A profiled cold screen for a cryogenic refrigerator according to claim 1, characterized in that: The supporting leg (15) is provided with two, and the two supporting legs (15) are fixedly installed with a shell (11) therebetween, the top surface of the shell (11) is provided with an upper cover (10), and the side surface of the shell (11) is provided with a side opening (17).

4. A profiled cold screen for a cryogenic refrigerator according to claim 3, characterized in that: The inner cavity of the shell (11) is provided with a shell inner surface (13), the outer side of the shell (11) is provided with a shell outer surface (14), and the shell inner surface (13) is directly made of wire cutting.

5. A profiled cold screen for a cryogenic refrigerator according to claim 3, characterized in that: The upper cover (10) is made of a thin-walled stainless steel plate, the middle part of the upper cover (10) is provided with a light transmission hole (12), and the light transmission hole (12) is circular.

6. A profiled cold screen for a cryogenic refrigerator according to claim 1, characterized in that: The vacuum cover (8) and the gas extraction interface (9) are communicated, and the end, away from the vacuum cover (8), of the gas extraction interface (9) is provided with a movable plug.

7. A profiled cold screen for a cryogenic refrigerator according to claim 4, characterized in that: The length value of the upper cover (10) is the same as that of the top of the shell inner surface (13), and the upper cover (10) and the shell (11) are in the same horizontal plane.

8. A profiled cold screen for a cryogenic refrigerator according to claim 1, characterized in that: The upper end of the inner cavity of the cover (2) is provided with a protruding block, and the surface of the protruding block is smooth, and the filter (1) is arranged on the top surface of the protruding block.

9. A shaped cold screen for a cryogenic refrigerator according to claim 1, characterized in that: The inner cavity of the lead ring (5) is provided with a rubber block, and a plurality of rubber blocks are arranged at equal intervals in a ring shape.

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