JP3467913B2 - Low temperature device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna using a cooling device, a communication device such as a detector, an infrared spectroscopic analyzer (IR).
Analysis), microwave spectroscopic analyzers and other scientific equipment, computer equipment, recording equipment, and other information equipment.

[0002]

2. Description of the Related Art Recently, as communication equipments, scientific equipments, information equipments, etc. have been improved in performance, it has been considered to use devices which play an important role in improving the performance in a low temperature environment. This is because, as is well known, not only can a superconducting device having extremely excellent performance be used, but also a semiconductor device can be made to have low noise, high speed, and high integration by making a low temperature environment.

Cooling devices for maintaining a low temperature environment can be roughly classified into two types, an open cycle type and a closed cycle type. The open cycle type functions as a so-called cryogen cooling, liquid refrigerant cooling using liquid nitrogen or liquid helium, solid refrigerant cooling using latent heat of sublimation such as solid argon or methane, and a low temperature sink such as outer space to function passively. There is radiant cooling. These are mainly used for cooling large devices such as supercomputers, linear motor cars, and electric energy storage devices.

The closed cycle type includes a Stirling cycle (ST) and a Gifford McMahon cycle (G
M), Bilmeier cycle (VM), Joule-Thomson cycle (JT), Brayton cycle (BR), pulse tube cycle and the like. These are mainly used in relatively small industrial and scientific equipment such as vacuum pumps (cryopumps) used in vapor deposition machines and sputtering equipment, cold traps, infrared image sensor cooling, and laser cooling.

In recent years, the latter closed cycle type, which has few restrictions on the place of use and can easily change the cooling temperature, has been receiving attention. As shown in FIG. 7, the structure of the cooling device apparatus using the normally closed cycle type is such that the device 8 is fixed and cooled on the cooling stage 1 cooled by the refrigerant, and the periphery thereof is insulated by a vacuum chamber (insulation chamber) 12 for heat insulation. It has a structure that covers it. Stainless steel is mainly used as the material of the vacuum chamber. Although abbreviated symbols are used in FIG. 7, a diffusion pump 17, a rotary pump 18 or a cryopump, a turbo molecular pump, etc. for drawing a vacuum are provided in the vacuum chamber.

[0006]

However, the low temperature device apparatus using the conventional closed cycle cooling apparatus has the following problems.

(1) Since a diffusion pump, a rotary pump, a cryopump, a turbo molecular pump and the like are provided side by side, downsizing is difficult.

(2) Since the structure is complicated, it requires specialist maintenance. For example, even if the device failed, it was returned to the manufacturer together with the refrigerator and repaired.

(3) Since the device and the refrigerator are not integrated and separated from each other, the user cannot freely select and install the required device.

If there are many restrictions as in (4) and (3), the refrigerator cannot produce the quantity, and if the quantity does not come out, the price is high. By the way, the price of a small cooling device is as high as 1 million yen or more even if it is the cheapest at present. However, it is said that less than 100,000 yen is possible if the quantity increases. These points have been a major obstacle to the spread of low-temperature device equipment to consumer equipment.

The present invention solves the above-mentioned problems and provides a low-temperature device which is small in size, easy to maintain, has a freely selectable device, and can be applied to consumer equipment at low cost. It is what

[0012]

To achieve the above object, according to the Invention The engagement groove or engagement with the periphery of the Oite cooling stage in the low-temperature device unit consisting of the present invention cryogenic device apparatus using the closed-cycle cooling system A closed-cycle cooling device that has a joint portion and holds the cylinder peripheral portion excluding the cooling stage in a vacuum;
It has an engaging portion or the engaging groove has a portion partially formed of a good thermal conductive material for connecting the cooling stage and thermally, and de <br/> devices periphery of the device apparatus held in vacuum Two you
Includes knit, said it made fitted to the device unit and the closed cycle cooling system, it is the device unit is capable of repeatedly detachable in the closed cycle cooling system, the engagement except where to thermally bonded material cross section of the engaging portion or the engaging groove is meander, that the thickness is 0.2mm or less, in the thermally bonded to the surface of the device unit or the closed cycle cooling system, in-Ga alloy It is characterized in that a film is formed. It is desirable to form the In and In-Ga alloy films on the device device side. further,
The low temperature device apparatus according to the present invention is a closed cycle type cooling device.
The low temperature device using the
The atmosphere around the device is nitrogen or an inert gas atmosphere.
That is, the pressure of the atmosphere around the device is 10
It is characterized in that it is ^-3 to 10 ^-4 Torr.

[0013]

EXAMPLES The present invention will be described in detail below with reference to examples.

The basic configuration of the low temperature device apparatus according to the present invention comprises a closed cycle cooling apparatus unit and a device apparatus unit.

The head portion of the closed cycle cooling device unit is shown in FIG. The closed-cycle type cooling system employs the most efficient and miniaturized Stirling cycle among closed-cycle cooling systems, and among them, the smallest cooling system that can cool below the liquid nitrogen temperature is used. First, a cylindrical outer frame A4 is set so as to cover the peripheral portion of the cylinder 2 of the closed-cycle cooling device while leaving the cooling stage 1. The outer frame A4 is made of stainless steel having a poor thermal conductivity, and the outer peripheral portion has a thickness of 1 mm, but the upper portion has a thickness of 0.02 to 0.
The cross-sectional shape is a meandering shape 6 at 2 mm. Next, the upper portion of the cylinder 2 and the outer frame A4 are welded to each other to form an engagement groove 5 on the outside by the cooling stage 1 and the outer frame 4, and an insulating chamber A7 on the inside by the cylinder 2, the flange 3 and the outer frame A4. Then 10 ^@ 5 Tor After degassing baked adiabatic chamber A7
The vacuum is evacuated to a pressure not higher than r, and the lower portion of the outer frame A4 and the flange 3 of the closed cycle cooling device are welded to hermetically maintain the heat insulating chamber A7 in a high vacuum state. Here, the reason why the thickness of the upper portion of the outer frame A4 was thinned to 0.02 to 0.2 mm and the cross-sectional shape was made into a meandering shape 6 to lengthen the heat conduction path was that the outer frame A4 was directed from the outer periphery toward the cooling stage 1. This is to suppress heat conduction as much as possible. Further, the reason why the cross-sectional shape is the meandering shape 6 is to reduce the strength by reducing the thickness of the outer frame A4 in order to suppress heat conduction, but there is also the purpose of supplementing it. As described above, the closed cycle cooling device unit 14 is obtained.

Next, the device unit is shown in FIG.
Basically, HEMT (high electron m)
device 8, such as a high-speed semiconductor device typified by an accessibility transistor, a superconducting device typified by a Josephson device, an intermediate body 9 thermally connected to the device 8, an engaging portion 1 that fits into the engaging groove 5.
0, an outer frame B11, and a heat insulating room B12. First, an engaging portion 10 having a meander-shaped cross section similar to that of the closed-cycle cooling device unit 14 is joined to an intermediate body 9 made of oxygen-free copper which is a good heat conductive material, and then mechanically fixed to the intermediate body 9. And I
The device 8 is bonded and fixed with a low melting point alloy such as an n-Ga alloy. Heat transfer coefficient κ (WK ^-1
m ^-2 ) is described in J. Appl. Phys. 27 (1956) 3
18 described in R. According to Berman's study, the pressure applied to the contact point is proportional to P as shown by κ = αP (α is a proportionality constant). That is, to improve the thermal conductivity κ, the pressure P
Need to be higher. However, since the device generally has no strength, increasing the pressure P causes breakage and performance deterioration.
By fixing the solids with a low melting point alloy having good thermal conductivity as in the embodiment, the heat transfer coefficient κ can be improved without applying a large pressure P. Next, the intermediate body 9 to which the devices 8 and the like are joined and the outer frame B11 are put in a vacuum chamber 1
0 ^-5 in a vacuum chamber was evacuated to a Torr or more pressure introducing dry nitrogen or inert gas 10 ^-3 to 10
^-4 Set pressure to Torr. Further, in this vacuum state, the engaging portion 1
0 and the outer frame B11 are joined, and the heat insulating chamber B12 is hermetically held in a vacuum state. The dry gas is introduced here in order to prevent deterioration of the device characteristics due to the release of H ₂ O, CO _{2 and the} like adsorbed on the surface such as the inside of the device 8 and the outer frame B11 and the inside with time. Especially, the oxide superconducting material which is the topic now is H
It is an indispensable step because it is easily deteriorated by ₂ O and CO ₂ . Further, it is necessary to properly use the material of the outer frame B11 according to the purpose of the low temperature device device. In particular, when electromagnetic waves such as radio waves and infrared rays are detected, the outer frame B11 is formed of a material such as quartz glass or soda glass that transmits electromagnetic waves instead of metal. In that case, a metal film such as Al or Ag or a dielectric multilayer film is formed at a predetermined position on the inner surface of the outer frame B11 in order to block noise and unnecessary electromagnetic waves. As a result, 13 device units are obtained.

Next, the closed cycle cooling device unit 14 and the device device unit 13 produced are fitted together as shown in FIG. 3 to obtain a low temperature device device. The fitting is performed by a screw method in which the surface irregularities formed by forming the engagement groove 5 and the engagement portion 10 in a meander shape are formed in a screw shape. The fitting state is shown in FIG. The closer the contact surface is, the more the heat transfer from the outer peripheral portion to the cooling stage 1 can be suppressed. In addition to the structure shown in FIG. 4A, the cross-sectional shape shown in FIG. Further, when a soft metal film such as In or In—Ga alloy is formed on the contact surface of the intermediate 9 with the cooling stage 1, the adhesion is improved, and the heat transfer efficiency from the cooling stage 1 to the intermediate 9 or the device 8 is increased. Will get better. More preferably, the low melting point metal is melted and bonded as described in the bonding of the device 8 and the intermediate 9. In that case, a metal such as In-Ga, which can be melted with a dryer, is preferable on the assumption that the user removes it, especially at home.

The ultimate temperature of the device 8 part of the obtained low temperature device and the temperature variation at 80K were measured.
The results are shown in Table 1 together with the conventional example. As the gas injected into the heat insulating chamber B12, He having poor heat insulating property (in other words, having good heat conductivity) is used, and the pressure is 8 × 10 ⁻³ Torr.

[0019]

[Table 1]

As can be seen from Table 1, although the cooling capacity is slightly inferior to that of the conventional example, the smallest closed-cycle cooling device for the oxide superconducting device (cooling capacity is a refrigerant) Since the cooling capacity is reduced when the size is reduced because it is proportional to the amount of He), and He, which has the worst adiabatic property as the injection gas, is sufficient. If the pressure in the heat insulating chamber B12 is in the range of 10 ⁻² Torr or more, the cooling capacity will be significantly reduced, so that it will be 10 ⁻³ Tor.
It is preferably rr or less. The material into which N ₂ or other inert gas is injected has a lower thermal conductivity than He and has a better heat insulating property, so that the temperature is lower than the ultimate temperature shown in Table 1 and there is little variation.

Next, instead of the device 8 of the intermediate 9,
The SrTiO ₃ substrate on which the oxide superconducting thin wire made of YBa ₂ Cu ₃ O _7-x having a width is formed is fixed and the device unit 13 is set to 1
The change in the critical temperature of the oxide superconducting thin wire was examined by putting 1500 H in a 20 ° C. constant temperature bath. The results are shown in Table 2 together with a comparative example in which no gas is injected into the heat insulation chamber B12 and a comparative example using another gas.
It was shown to.

[0022]

[Table 2]

As can be seen from Table 2, by injecting nitrogen or an inert gas into the heat insulating chamber B12, lowering of the critical temperature, that is, deterioration is suppressed. This is because by injecting a gas that does not affect the oxide superconductor, the adhesion of H ₂ O or the like to the oxide superconducting thin wire is suppressed. Degradation due to H ₂ O is considered to be decomposition according to Eq. (1) when explained using a Y-based superconductor.

2Ba ₂ YCu ₃ O ₇ + 6H ₂ O → 3Ba (OH) 2 + Y ₂ BaCuO ₅ + 5CuO + 2O ₂ (1) When CO 2 is added to this, a carbon-containing compound such as BaCO ₃ is generated and the deterioration further progresses. Conceivable. By the way, many decomposition products in the air contain carbon-containing compounds.

Although the cost is increased, such a gas injection is not necessary when baking for a long time to remove problematic H ₂ O and the like. Further, it is preferable that the gas is not liquefied at the use temperature. For example, Ar and Kr are liquefied at the critical temperatures shown in Table 2, but it is effective because device devices such as storefronts and inventory storage are not always in a cooled state.

In this embodiment, the concave portion, that is, the engaging groove is provided on the closed cycle cooling device unit 14 side, but even if it is provided on the device device unit 13 side as shown in FIG. 5, the shape of the engaging groove is as shown in FIG. It does not matter if it is cylindrical. In the case of a cylindrical shape, as can be seen from the figure, it is more preferable because the heat penetration path from the outer peripheral portion to the meandering portion can be lengthened and the heat insulating property is further improved. Further, although the Stirling cycle is used as the closed cycle cooling device, the effect is the same even if other closed cycle cooling devices such as Gifford McMahon cycle, JT cycle, pulse tube cooling device are used, and there is no problem.

[0027]

Since the present invention is constructed as described above, it has the following effects.

It is composed of a device unit having a device peripheral portion kept in vacuum and a closed cycle cooling device unit having a cylinder peripheral portion kept in vacuum. The fitting unit of the device unit and the closed cycle cooling device unit is shaped like a meander. By lengthening the heat penetration path and making it meandering to have strength to keep the wall thickness as thin as possible, it is possible to remove the device unit and the cooling unit, and when a failure occurs the user can replace the failed part. It's easy now. Further, it has become possible to freely select, for example, a semiconductor device HEMT or a superconducting device Josephson device in accordance with a required characteristic or purpose by using a common cooling device. Such ease of maintenance and improvement in the degree of freedom of application enable the widespread use of high-performance low-temperature device devices in homes. In addition, increased demand leads to lower prices for closed-cycle cooling systems, and lower prices lead to increased demand, leading to a good cycle.

[Brief description of drawings]

FIG. 1 is a partial vertical cross-sectional view of a closed cycle device unit of a low temperature device device according to a first embodiment of the present invention.

FIG. 2 is a partial vertical cross-sectional view of the device unit of the low-temperature device device according to the first embodiment of the present invention.

FIG. 3 is a partial vertical sectional view of a low temperature device device according to a first embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a fitting portion of the low temperature device device according to the first embodiment of the present invention.

FIG. 5 is a partial vertical cross-sectional view of a low-temperature device device according to a second embodiment of the present invention.

FIG. 6 is a partial vertical cross-sectional view of a low temperature device device according to a third embodiment of the present invention.

FIG. 7 is a partial vertical cross-sectional view of a conventional low temperature device device.

[Explanation of symbols]

1 ... Cooling stage 2 ... Cylinder 3 ... Flange 4 ... Outer frame A 5: Engagement groove 6 ... Men-under shape 7 ... Insulation room A 8 ・ ・ ・ Device 9 ... Intermediate 10 ... Engagement part 11 ... Outer frame B 12 ... Insulation room B 13 ... Device unit 14 ... Closed cycle cooling device unit 15 ... Lead wire 16 ... Connector 17 ... Diffusion pump 18 ... Rotary pump

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Tatsuya Shimoda Inventor Tatsuya Shimoda, 3-5 Yamato, Suwa City, Nagano Seiko Epson Corporation (56) Reference JP-A-3-131726 (JP, A) JP-A 8-200864 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25B 9/00 G01J 5/02 H01L 23/34

Claims (6)

(57) [Claims] 1. A closed holding has a engagement groove or engagement portion on the peripheral portion of the Oite cooling stage to a low temperature device apparatus using the closed-cycle cooling system, and a cylinder peripheral portion excluding the cooling stage vacuum A cycle cooling device and a device device having an engaging portion or an engaging groove having a portion which is partly made of a good heat conductive material and thermally connected to the cooling stage, and which holds the device peripheral portion in vacuum . comprises units, cryogenic devices apparatus characterized by comprising fitted from the device <br/> chair device and the closed cycle cooling system. 2. The low temperature device device according to claim 1, wherein the device device is repeatedly attachable to and detachable from the closed cycle cooling device. Wherein the engagement portion or the engagement groove of the material cross-section except where thermally bonding a meander, of claim 1, wherein the thickness thereof is 0.2mm or less Low temperature device equipment. Wherein said device unit or the In thermally bonded to the surface of the closed cycle cooling system, cold device according to claim 1, wherein the forming the In-Ga alloy layer. 5. The device in the device device
Features a nitrogen or inert gas atmosphere around the perimeter
The low-temperature device device according to claim 1. 6. The pressure of the atmosphere around the device is 10
^-3 to 10 ^-4 Torr.
5. The low temperature device device according to 5.