JPH09257581A - Infrared detector - Google Patents

Abstract

(57) Abstract: In an infrared detection device that uses an infrared detection element cooled to about 30 to 80K, the cooler is downsized by reducing the heat load in the cooling part. Further, by increasing the rigidity of the cylinder, the image quality and reliability of the infrared detection device are improved. A second cylinder (20) cooled to about 30 to 80K is added to the inside of the first cylinder (8). A ceramic wiring board 40 is arranged between the first cylinder 8 and the cooling unit 6 to perform wiring inside and outside the cylinder. Further, the cylinder 8 and the filter 9 are made of materials having a linear expansion coefficient close to each other, and the two are bonded by adhesion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared detecting device for cooling an infrared detecting element to about 30K-80K.

[0002]

2. Description of the Related Art FIG. 6 is a cross-sectional view showing a conventional infrared detecting device, in which 1 is a base made of stainless steel, 2
Is an outer cylinder 3 made of, for example, stainless steel fixed to the base 1.
Is a window made of, for example, silicon or germanium, which transmits infrared rays held in the outer cylinder 2, 4 is a first inner cylinder made of, for example, a titanium alloy fixed to the base 1, and 5 is a smaller diameter than the first inner cylinder 4. For example, a second inner cylinder made of a titanium alloy, 6 is a disk made of, for example, copper between the first inner cylinder 4 and the second inner cylinder 5, and 1 to 6 are hermetically bonded to each other. 7 is an infrared detecting element held by the second inner cylinder 5, 8 is a disk 6
A first cylinder 9 made of, for example, Kovar, mounted on top of the filter, 9 is attached to the first cylinder 8 and is a filter for transmitting only infrared rays of a selected wavelength, 10 is a filter 9
A plate made of, for example, aluminum for fixing the device, 11 is a fixing screw, 12 is an exhaust pipe, 13 is an infrared detection element 7 at about 30 to 80K, and the disk 6 is at about 80 to 130.
It is a cooling rod of a cooler for cooling to K. Reference numeral 14 is a wiring for extracting an electric signal from the infrared detection element 7 to the outside of the dewar, 15 is an internal terminal insulated from the first cylinder 8, 16 is an external terminal insulated from the outer cylinder 2, and connected to the wiring 14. Has been done. Reference numeral 17 denotes Dewar. 18 is the first
It is a film having a high emissivity, such as black chrome plating, formed on the inner surface of the cylinder 8.

Next, the operation will be described. In general, an infrared detection element that receives infrared rays needs to be cooled to about 30 to 80K in order to reduce noise due to heat. Although liquid nitrogen or a cooler is used for cooling, it is necessary to reduce (insulate) heat for cooling the infrared detection element from the ambient temperature side as much as possible for efficient cooling. Therefore, as shown in FIG. 6, the infrared detecting element 7 is first attached to the tips of the elongated cylinders 4 and 5 to reduce the invasion of heat due to conduction from the base 1 exposed to the ambient temperature. In addition, in order to eliminate heat transfer due to convection, the infrared detection element 7 includes the base 1 and the outer cylinder 2
It is inside the container sealed by the window 3, the inner cylinders 4, 5 and the disk 6, and the inside is evacuated by the exhaust pipe 12 and kept in vacuum. The cooling rod 13 of the cooler is inserted into the inner cylinders 4 and 5, and the infrared detection element 7 is placed at about 30-80K from the bottom surface.
In addition, the first cylinder 8 and the filter 9 are cooled to about 80 to 130K via the disk 6. The first cylinder 8 absorbs unnecessary infrared rays from the outside of the Dewar by the film having a high emissivity formed on the inner surface, and is cooled to about 80 to 130K, so that the unnecessary unnecessary infrared rays are generated. Hold down. The filter 9 transmits only infrared rays having a sensitive wavelength to the infrared detection element 7 and reflects unnecessary infrared rays, and at the same time, the filter 8
Cooled to 0 to 130K, it suppresses the generation of unnecessary infrared rays.

Infrared rays 1 incident on the Dewar through the window 3
9 is imaged by the infrared detecting element 7 and converted into an electric signal, is output from the external terminal 16 to the external signal processing device through the wiring 14 and the inner end portion 15, and is displayed as image information.

[0005]

Since the conventional infrared detecting device is constructed as described above, the cooler simultaneously cools the infrared detecting element to about 30K to 80K and the cylinder and the filter to about 80K to 130K. Needed and requires a large cooling capacity. The size and mass of the cooler increase in order to increase the cooling capacity, which is an obstacle to downsizing the infrared camera.

Further, the internal terminal 15 attached to the first cylinder 8 cannot cope with the increase in the number of wirings accompanying the increase in the number of pixels of the infrared detecting element 7, which causes a decrease in the rigidity of the cylinder itself. The structure in which the filter 9 is fixed by the screw 11 also increases the weight of the tip of the cylinder, which is a factor of lowering the rigidity of the cylinder. If the rigidity of the cylinder is low, vibrations from the outside will cause deflection of the cylindrical opening and interference with other parts,
This is an obstacle to improving the image quality and reliability of the infrared detection device.

The present invention has been made to solve the above problems, and an object thereof is to reduce the size, image quality and reliability of an infrared detection device.

[0008]

The infrared detector according to the first aspect of the invention has an opening on the filter side, is mounted on the infrared detecting element, and has the same temperature as that of the tip of the second inner cylinder. It comprised a second cylinder to be cooled.

The infrared detector according to the second invention is the first infrared detector.
A film having a low emissivity was formed on the inner and outer surfaces of the cylinder.

The infrared detector according to the third aspect of the invention is the second aspect of the invention.
A low emissivity film was formed on the outer surface of the cylinder and a high emissivity film was formed on the inner surface.

An infrared detector according to a fourth aspect of the present invention comprises a ceramic multilayer wiring board between the disk and the first cylinder.

An infrared detecting device according to a fifth aspect of the present invention is the first aspect.
Molybdenum was used as the material of the cylinder and germanium was used as the material of the filter, and both were bonded by adhesion.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. First Embodiment FIG. 1 is a sectional view of an infrared detection device showing a first embodiment of the present invention. In FIG. 1, 1 to 17 are exactly the same as the conventional device. 20 has an opening on the side of the filter and is mounted on the infrared detection element 7,
It is a second cylinder made of, for example, a titanium alloy that is cooled to substantially the same temperature as the tip portion of the second inner cylinder. The unnecessary infrared ray 21 emitted from the first cylinder 8 is blocked by the second cylinder 20 and does not reach the infrared detection element 7. Therefore, in order to suppress generation of unnecessary infrared rays from the first cylinder 8 to the infrared detection element, it is not necessary to cool the first cylinder 8 to a low temperature of about 80 to 130K, and to about 130 to 170K. It is enough. Therefore, the cooling capacity required for the cooler 13 is reduced.

Embodiment 2 FIG. Embodiment 2 FIG. 2 is a partial cross-sectional view of a dewar showing Embodiment 2 of the present invention.
Films 30 and 31 having low emissivity, such as gold plating and nickel plating, are formed on the inner and outer surfaces of the cylinder 8. Unwanted infrared rays 32 incident from the outside of Dewar
Is reflected on the inner surface of the first cylinder 8 but the second cylinder 2
It is blocked by 0 and does not reach the infrared detection element 7. Therefore, it is not necessary to provide a film having a high emissivity on the inner surface of the first cylinder 8 in order to suppress reflection of unnecessary infrared rays on the inner surface of the first cylinder 8. By providing the inner surface of the first cylinder 8 with a film having a low emissivity, the infrared rays emitted from the first cylinder 8 are reduced, and the second cylinder 20 is reduced.
The energy absorbed by the heat is reduced. Also, the first
By providing a film having a low emissivity on the outer surface of the cylinder 8, the infrared rays absorbed by the first cylinder 8 are reduced and the energy absorbed as heat is reduced. As a result, the heat load on the cooler 13 is reduced, and the infrared detecting element 7 can be cooled to a predetermined temperature even if the cooling capacity of the cooler 13 is small.

Embodiment 3 FIG. 3 is a partial cross-sectional view of a dewar showing Embodiment 3 of the present invention.
A film 33 having a low emissivity such as gold plating or nickel plating is formed on the outer surface of the cylinder 20, and a film 34 having a high emissivity such as black chrome plating is formed on the inner surface. By providing a film having a low emissivity on the outer surface of the second cylinder 20, infrared rays absorbed by the second cylinder 20 are reduced, and energy absorbed as heat is reduced. As a result, the heat load on the cooler 13 is reduced, and the infrared detecting element 7 can be cooled to a predetermined temperature even if the cooling capacity of the cooler 13 is small. In addition, the second cylinder 20
By providing a high emissivity film on the inner surface of
Unwanted infrared rays 35 from the outside of the Dewar can be absorbed and reflection can be suppressed, and unnecessary infrared rays do not reach the infrared detection element 7. Thereby, a high quality infrared image can be obtained.

Embodiment 4 4 is a sectional view of a dewar showing Embodiment 4 of the present invention, in which 40 is a ceramic multilayer wiring board arranged between the disk 6 and the first cylinder 8, and 41a and 41b are ceramic wiring boards 40. The pins are provided above and electrically connected through the internal wiring of the ceramic wiring board 40. A ceramic can form a vacuum container by brazing with a metal, and it is easy to form a multilayer and a complicated wiring can be formed inside. An electric signal from the infrared detecting element passes from the wiring 14 to the pin 41a, is taken out to the outside through the internal wiring of the ceramic multilayer wiring board, the pin 41b, and the external terminal 16. The ceramic wiring board is fixed to the disk 6 by screwing, bonding or the like. Therefore, it is not necessary to form holes in the first cylinder 8 for arranging the internal terminals, and the rigidity of the cylinder can be improved.

Embodiment 5 5 is a cross-sectional view of a Dewar showing Embodiment 5 of the present invention. In the figure, molybdenum is used as the material of the first cylinder 8 and germanium is used as the material of the filter 9, and both are bonded by adhesion. . The average linear expansion coefficient from room temperature to 80K is germanium 35.5.
× 10 ^-7 (1 / K), Molybdenum 28 × 10 ^-7 (1 /
K), which is very close. Excessive stress does not occur at the joint even during cooling, so that the joint can be achieved by adhesion. Since metals having a low expansion coefficient other than molybdenum have low thermal conductivity, the temperature difference between both ends of the first cylinder 8 becomes large and the filter cannot be cooled (example of thermal conductivity Invar:
11.6 W / mK, Kovar: 10 W / mK). The thermal conductivity of molybdenum is 200 W / mK, and the first cylinder 8
The temperature difference between both ends is small. Therefore, the combination of the above materials makes it possible to join them by adhesion, so that the plate for fixing the filter and the fixing screw are unnecessary, and the first cylinder 8 can be made lighter and its rigidity can be improved. .

[0018]

According to the first aspect of the present invention, since the second cylinder, which is cooled to substantially the same temperature as the tip of the second inner cylinder, is provided, the first cylinder is cooled to a low temperature of about 80 to 130K. Cooling to about 130-170K is sufficient. As a result, the infrared detecting device using the present invention has a smaller cooling capacity of the cooler than the conventional one, and consumes less power than the conventional infrared detecting device, and at the same time is small in size and small in mass.

Further, according to the second invention, since the film having a low emissivity is provided on the inner surface of the first cylinder, the infrared rays radiated from the first cylinder are reduced, and the second cylinder is reduced. The energy absorbed by the cylinder as heat is reduced. Therefore, about 30 ~
The heat load in the low temperature part of 80K becomes small. Further, since the film having a low emissivity is provided on the outer surface of the first cylinder, the infrared rays absorbed by the first cylinder are reduced and the energy absorbed as heat is reduced. Therefore, about 80-130
The heat load in the low temperature part of K becomes small. From the above, the infrared detecting device using the present invention has a smaller cooling capacity of the cooler than the conventional one, and consumes less power than the conventional infrared detecting device, and at the same time, can be small in size and small in mass.

According to the third invention, since the outer surface of the second cylinder is provided with the film having a low emissivity, the infrared rays absorbed by the second cylinder are reduced and absorbed as heat. Energy is reduced. Therefore, the heat load in the low temperature part of about 30 to 80K is small. As a result, the infrared detection device using the present invention has a lower cooling efficiency of the cooler than the conventional one, and consumes less power than the conventional infrared detection device, and at the same time, can be small in size and small in mass. Further, since the film having a high emissivity is provided on the inner surface of the second cylinder, unnecessary infrared rays from the outside of the Dewar can be absorbed and the reflection can be suppressed. Does not reach Thereby, the infrared detection device using the present invention,
A high quality infrared image can be obtained.

According to the fourth invention, the ceramic multilayer wiring board is provided between the disk and the first cylinder.
It is not necessary to perform hole processing or the like on the cylinder to arrange the internal terminals, and the rigidity of the first cylinder can be improved. Therefore, even when external vibration is applied, it is difficult to cause the runout of the opening of the first cylinder and the interference with other parts.
The image quality and reliability of the infrared detection device can be improved.

According to the fifth invention, molybdenum is used as the material of the first cylinder and germanium is used as the material of the filter, and both are bonded by adhesion, so that the plate for fixing the filter and the fixing screw are It is unnecessary, and the first cylinder is lightened and the rigidity can be improved. Therefore, even when external vibration is applied, it is difficult to cause the runout of the opening of the first cylinder and the interference with other parts.
The image quality and reliability of the infrared detection device can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of an infrared detection device according to the present invention.

FIG. 2 is a diagram showing a second embodiment of an infrared detecting device according to the present invention.

FIG. 3 is a diagram showing Embodiment 3 of the infrared detection device according to the present invention.

FIG. 4 is a diagram showing Embodiment 4 of the infrared detection device according to the present invention.

FIG. 5 is a diagram showing Embodiment 5 of the infrared detection device according to the present invention.

FIG. 6 is a diagram showing a configuration of a conventional infrared detection device.

[Explanation of symbols]

1 unit, 2 outer cylinder, 3 windows, 4 first inner cylinder, 5 2nd
Inner cylinder, 6 disc, 7 infrared detecting element, 8 first cylinder, 9 filter, 10 plate, 11 fixing screw, 12 exhaust pipe, 13 cooler cooling rod, 14 wiring, 15 internal terminal, 16 external terminal, 17 Dewa,
18 High emissivity film, 19 Infrared ray, 20 Second cylinder, 21 Infrared ray, 30 Low emissivity film, 31
Low emissivity film, 32 infrared rays, 33 Low emissivity film, 34 High emissivity film, 35 Infrared ray, 40 Ceramic wiring board, 41 pins.

Claims (5)

[Claims] 1. A window for transmitting infrared rays, an outer cylinder sealed and joined to the window at an end thereof, a stand sealed and joined to the other end of the outer cylinder, and the stand. Of the first inner cylinder sealed and joined at the end to the hole in the center of the disk, the disk sealed and joined to the other end of the first inner cylinder, and the other of the disks A vacuum container composed of a second inner cylinder sealed and bonded to the surface, an infrared detection element provided at the tip of the second inner cylinder, and the window side attached to the disk A first cylinder having an opening on the infrared detecting element and having a filter bonded to the opening, and a second cylinder having an opening on the side of the filter. An infrared detector comprising: a cylinder. 2. A film having a low emissivity is provided on the inner and outer surfaces of the first cylinder.
Infrared detector described. 3. The infrared detecting device according to claim 1, wherein a film having a low emissivity is provided on an outer surface of the second cylinder, and a film having a high emissivity is provided on an inner surface of the second cylinder. 4. The infrared detection device according to claim 1, further comprising a ceramic multilayer wiring board provided between the disk and the first cylinder. 5. The material of the first cylinder is molybdenum,
The infrared detector according to claim 1, wherein germanium is used as a material of the filter.