JPH01250026A - Infrared detecting device - Google Patents

Abstract

PURPOSE:To prevent a Dewar which incorporates an infrared detecting element from breaking by fixing the Dewar to the expander of a refrigerator which cools the infrared detecting element across an elastic body. CONSTITUTION:The elastic body 13 is interposed between the Dewar 2 and expander 6, so this elastic body 13 deforms by vibrations from the expander 6 to absorb the vibration energy of the expander 6. The elastic body 13 reduces the vibrations transmitted to the Dewar 2 and cuts them off. Consequently, the Dewar 2 is prevented from breaking owing to the vibrations that the expander 6 generates.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides HgCd, which is mounted on, for example, a guided flying vehicle or an infrared imaging device, and which is cooled to an extremely low temperature.
This invention relates to an infrared detection device using an infrared detection element such as Te or InS.

[Conventional technology]

Figure 4 shows a conventional infrared detection device (Utility Model No. 61-7
(Refer to No. 6326), this device is roughly composed of a dual unit 2 containing an infrared sensing element 1, and a refrigerator 3 for cooling the infrared sensing element 1 to an extremely low temperature, for example, 77°C.

As the refrigerator 3, one that utilizes a refrigeration cycle such as a Stirling cycle or a Gifford McMahon cycle is often used. The refrigerator 3 is composed of a compressor 4, an expander 6, and a connecting pipe 5 that connects both 4 and 6. The expander 6 is provided with an elongated cylindrical projection called a cold finger 7. The structure is such that freezing occurs from the tip of the cold finger 7.

The Dua 2 has a double-walled structure consisting of an outer shell 8 and an inner shell 9. The infrared detection element 1 is attached to the tip of the inner shell 9, and the outer shell 8 transmits infrared rays. A window 10 is provided.

A space 11 between the outer shell 8 and the inner shell 9 is kept in a vacuum to prevent heat from entering the infrared sensing element 1 and the tip of the cold finger 7 from the outside. On the surfaces (inner surfaces) of the outer shell 8 and the inner shell 9 on the space 11 side, a vapor deposited film or a plating film of a substance with a low radiation index, such as aluminum or a, is formed, and both shells 8, 9 are made of a material with low thermal conductivity, such as glass.

12 is a thermal interface attached to the tip of the cold finger 7, which absorbs dimensional changes due to the difference in thermal expansion coefficient between the cold finger 7, which is generally made of metal, and the inner shell 9, which is generally made of glass. It is for the purpose of This thermal interface 12 is made of a material that is elastic and has high thermal conductivity, such as laminated copper foil, and its tip is always in close contact with the bottom surface of the inner shell 9.

Next, the operation will be explained.

When the refrigerator 3 starts operating and begins to generate refrigeration at the tip of the cold finger 7, the infrared detecting element 1 receives heat from the refrigerator 3 via the thermal interface 12, and its temperature drops to 77. When the temperature drops to around 10
It begins to detect infrared rays that penetrate more and more.

On the other hand, in the Dua 2, the space 11 between the outer shell 8 and the inner shell 9 is kept in a vacuum, and the inner surfaces of the outer shell 8 and the inner shell 9 are provided with a vapor-deposited film or a plating film with a low radiation rate. In addition, since the inner and outer shells 8.9 are made of materials with low thermal conductivity, these reduce heat intrusion from the outside through convection, radiation, and conduction, and the refrigerator 3.
reduce the load on

(Problem to be Solved by the Invention) In the conventional infrared detection device as described above, the outer shell 8 and the inner shell 9 of the Duure 2 are made of glass, which is a material with low thermal conductivity, and the Duure 2 and the inner shell 9 are made of glass, which is a material with low thermal conductivity. Since the expander 6 is firmly fixed with adhesive or bolts,
The vibrations generated by the expander 6 cause cracks to occur in the outer shell 8 and inner shell 9, reducing the degree of vacuum in the space 11.
There were problems such as a decline in the functionality of Dua 2 itself.

This invention was made in order to solve the problem of the conventional interlayer point, and an elastic body is interposed between the dure 2 and the expander 6, and the vibration generated from the expander 6 is absorbed by the elastic body. The purpose of this invention is to eliminate damage to the dual 2 and provide a highly reliable infrared detection device.

[Means to solve the problem]

The infrared detection device according to the present invention has a structure in which a dual unit containing an infrared detection element is fixed via an elastic body to an expander of a refrigerator that cools the infrared detection element.

[Effect]

Since the duure is fixed to the expander via the elastic body, vibrations of the expander are absorbed and blocked by the elastic body, and almost no vibrations are transmitted to the duure. therefore,
According to this invention, it is possible to prevent damage to the duer due to vibration of the expander.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

In the figure, 1 to 12 indicate the same parts as in FIG. Reference numeral 13 denotes an elastic body such as rubber or sponge installed between the duure 2 and the inflator 6.
It is fixed to the expander 6 via.

With this configuration, when the compressor 4 starts operating, a pressure change occurs in the working gas sealed inside, and this pressure change drives the expander 6 through the connecting pipe 5. Then, a piston (not shown) in the expander 6
Freezing begins to occur at the tip of the cold finger 7 due to the reciprocating motion of the cold finger 7. At this time, an inertial unbalanced force is generated in the expander 6 due to the reciprocating movement of the piston, and this is transmitted to the dual 2 as vibration.

However, since the elastic body 13 is interposed between the dure 2 and the expander 6, this elastic body 13 is deformed by the vibration from the expander 6 and absorbs the vibration energy of the expander 6. The elastic body 13 reduces and blocks the vibrations transmitted to the dure 2 in this way.

Figure 2 shows the vibration transmissibility T (during 2 shooting/
This is a graph schematically showing vibrations of the expander 6, and the vibration blocking effect increases as the frequency f increases.

As described above, in this embodiment, the vibrations from the expander 6 can be effectively absorbed and blocked by the elastic body 13, and the transmission of vibrations to the dua 2 can be reduced, so that the vibrations generated by the expander 6 can be reduced. Damage to the dua 2 due to vibration can be prevented.

Therefore, the reliability of the infrared detection device is significantly improved.

In addition, in the above embodiment, the elastic body 1 such as rubber or sponge
3 is used to isolate the vibration of the expander 6, but as shown in FIG. The vibration of the expander 6 can be blocked, and the same effect as in the above embodiment can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, since an elastic body that absorbs vibration is interposed between the expander and the dure, damage to the duer due to the vibration of the expander is eliminated, and a highly reliable infrared detection device is obtained. be able to.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an infrared detection device according to an embodiment of the present invention, FIG. 2 is a graph showing the vibration isolation effect of the elastic body in FIG. 1, and FIG. 3 is an infrared detection device according to another embodiment of the invention. FIG. 4 is a block diagram showing a conventional infrared detection device. 1 is an infrared detection element, 2 is a dual unit, 3 is a refrigerator, 4 is a compressor, 5 is a connecting pipe, 6 is an expander, 7 is a cold finger, 8 is an outer shell, 9 is an inner shell, 10 is a window, 11 is a space, 12 is a thermal interface, 13 is an elastic body,
14 is a metal bellows. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Figure 1 7: Cold Fi〉Power゛- 8 Two external systems Ciel 9: Inner monk Figure 2 Fitting comparison f @Figure 3 Figure 4

Claims (1)

[Claims] An infrared detection device characterized in that a dua containing an infrared detection element is fixed via an elastic body to an expander of a refrigerator that cools the infrared detection element.