JPH10242313A - Vacuum vessel for housing photoelectric element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the position accuracy of an infrared detector element in a photoelectric conversion element-housing vacuum vessel. SOLUTION: The vessel comprises a case 41, an infrared detector element assembly fitted to the top of an inner tube 41a of the case 41, an outer tube 42 covering the inner tube 41a to form a vacuum space 44 between the tubes 41a, 42. The case 41 is made by forming a preform by a lathe, so that its base 41c is concentric to the inner tube 41a having a wall thin but nearly keeping its strength. The vessel 40 is mounted such that the base 41c is fitted in a recessed mount 61 of a probing apparatus 60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum container containing a photoelectric conversion element, and more particularly, to a vacuum container containing a photoelectric conversion element which is mounted in an apparatus main body, in which an infrared detecting element requiring cooling is accommodated in a vacuum atmosphere. About. As one of devices for observing the earth, there is a search device mounted on an aircraft or the like and detecting infrared rays emitted from the earth. This search device uses an infrared detecting element. Here, the infrared detecting element is used after being cooled to an extremely low temperature, which is the temperature of liquid nitrogen, in order to suppress a dark current that becomes noise. In order to prevent dew condensation from occurring when cooled to extremely low temperatures, and to enhance the heat insulating effect, the area around the infrared detecting element needs to be evacuated.

As shown in FIG. 8, the above exploration apparatus 10 includes an exploration apparatus main body 14 provided with a cooling device 13 and an infrared detection element housing vacuum container 12 housing an infrared detection element 11 in a vacuum atmosphere. It is a configuration that is attached to and assembled. The cooling device 13 uses, for example, the principle of the reverse Stirling cycle, and the like.
, An expander 16 and a cooling head 17. The exploration device 10 activates the compressor 15 to operate the cooling device 13 and the infrared detection element 1
1 is cooled to a very low temperature.

[0003] In recent years, the number of pixels of the infrared detecting element has been increasing in order to increase the precision of the search. When the number of pixels of the infrared detecting element increases, the size of a region corresponding to one pixel on the infrared detecting element decreases, and therefore, it is necessary to determine the position of the infrared detecting element in the search device with higher accuracy. This requires a configuration in which the position of the infrared detection element with respect to the search device is more accurately determined when the vacuum container containing the infrared detection element is attached to the main body of the search device when the vacuum container containing the infrared detection element is attached. .

It is also required that the infrared detecting element can be efficiently cooled to a very low temperature.

[0005]

2. Description of the Related Art A conventional vacuum vessel 20 containing an infrared detecting element.
9, an inner cylinder 21 into which a cooling head is inserted, an outer cylinder 22 welded to the inner cylinder 21 to cover the inner cylinder 21, and an infrared detecting element attached to the top of the inner cylinder 21. 23 and a cold shield 24 that covers the infrared detecting element 23, and has a vacuum space 25 between the inner cylinder 21 and the outer cylinder 22.

The outer cylinder 22 has a window 26. The inner cylinder 21
As shown in FIG. 10, a glass tube 30, a head 31 fixed to the top surface of the tube 30, a joint 32 fitted and fixed to the lower end of the tube 30, and a joint with the joint 32 And a getter case 34 fitted and welded to the base 33. A getter 36 is provided in the getter case 34 and absorbs the gas generated in the vacuum chamber 20 containing the infrared detecting element.

[0007] The vacuum vessel 20 containing the infrared detecting element is shown in FIG.
As shown in the figure, the getter case 34 is fitted to the concave mounting portion 14a of the search device main body 14 and welded. The cooling head 17 is inserted into the inner cylinder 21, and the top of the cooling head 17 is in thermal communication with the head 31. Here, the reason why the cylinder 30 is made of glass is that the thermal conductivity of the glass is small. That is, it is possible to efficiently cool the infrared detecting element 23 in a normal temperature state to an extremely low temperature. The thickness t1 of the cylinder 30 is about 1 mm in consideration of strength.

[0008]

Since the inner cylinder 21 has a structure in which a plurality of parts are combined, the accumulated dimensional deviation of the combination part of each part becomes the deviation of the head 31 from the getter case 34. . The combination part of the parts is between the cylinder 30 and the head 31, the cylinder 30 and the joint 3
2 and between the joint 32 and the base 33 and between the base 33 and the getter case 34, and it is difficult to reduce the amount of deviation of the head 31 from the getter case 34. For this reason, there is a limit in improving the positional accuracy and parallelism of the infrared detecting element 23 with respect to the searching device 35 when the vacuum container 20 containing the infrared detecting element is attached to the searching device main body 14. For this reason, when an infrared detecting element having a large number of pixels is used, it is difficult to mount the infrared detecting element with good accuracy according to the number of pixels, and as a result, the image quality of the obtained image is reduced. There was fear. In addition, after the vacuum vessel 20 containing the infrared detecting element is attached to the exploration apparatus main body 14, a troublesome work of adjusting the position is required, and the assembling of the exploration apparatus 35 is troublesome.

Further, as the number of pixels increases, the size of the infrared detecting element increases.
You need to use When the diameter of the cylinder 30 is increased, the volume of the cylinder 30 increases, and the heat capacity of the cylinder 30 increases. Therefore, it takes a long time to cool the infrared detecting element 23 in a normal temperature state to a very low temperature, and It takes time to start the operation, and the power consumption increases.

[0010] Therefore, an object of the present invention is to provide a vacuum container for housing a photoelectric conversion element which solves the above-mentioned problems.

[0011]

According to the first aspect of the present invention, there is provided an inner cylinder, an outer cylinder covering the inner cylinder, and a photoelectric conversion element requiring cooling attached to a top of the inner cylinder. A vacuum space between the inner cylinder and the outer cylinder in which the photoelectric conversion element is disposed, and in a photoelectric conversion element housing vacuum container attached to the apparatus main body, the material is cut and cut out. It has a formed inner cylinder part and a base part integrally, and has a photoelectric conversion element mounting part to which a photoelectric conversion element assembly having the photoelectric conversion element is fitted and mounted at the top of the inner cylinder part. The inner cylinder portion has a container body having a thickness small enough to maintain strength; the photoelectric conversion element assembly is fitted and mounted on the photoelectric conversion element mounting portion; A container, wherein the base portion of the container body is fitted to the device body, Is obtained by a structure mounted to the body.

According to a second aspect of the present invention, there is provided a flexible cable having a structure in which a wiring pattern made of a copper thin film is adhered on a base made of a synthetic resin having flexibility without using an adhesive. In order to take out, a wiring is provided in the vacuum space.

[0013]

FIG. 1 shows a vacuum container 40 containing an infrared detecting element according to an embodiment of the present invention. The vacuum vessel 40 containing the infrared detecting element has a vessel main body 41, an outer cylinder 42, and a wiring board 43 shown in FIG.
2 has a vacuum space 44 therebetween. In a vacuum space 44, an infrared detecting element 45 as a photoelectric conversion element is provided.
, Flexible cable 46 and cold shield 4
7 and a getter 48.

The container main body 41 is formed by lathe-cutting a Kovar material as will be described later, and includes an inner cylindrical portion 41a and a concave infrared detecting element mounting portion at the top of the inner cylindrical portion 41a. 41b, a substantially cylindrical base portion 41c extending outward from the lower end side of the inner cylindrical portion 41a, a substantially cylindrical getter case portion 41d connected to the base portion 41c and located above the base portion 41c. Is integrated. The infrared detecting element mounting portion 41b has a circular concave shape.

The container body 41 is formed by lathing a Kovar material as described later, and is formed by cutting. The center 01 of the infrared detecting element mounting portion 41b and the center 02 of the base portion 41c are Center line CL1 of container body 41
It is located with high accuracy. Also, the parallelism between the surface S1 of the infrared detecting element mounting portion 41b and the surface S2 at the lower end of the base portion 41c has good accuracy.

The thickness t1 of the inner cylindrical portion 41a is a minimum thickness necessary for the container main body 41 to maintain a predetermined mechanical strength, for example, 0.1 mm. Since the material is metal, the container body 41 has a predetermined mechanical strength even if the thickness t1 is 0.1 mm. As shown in FIG. 3, the infrared detecting element 45 is previously assembled in the form of an infrared detecting element assembly 50. The infrared detecting element 45 is a bump 51 made of In.
By flip-chip bonding on a sapphire substrate 52. The substrate 52 is made of an adhesive sheet 53 made of In.
Thus, it is adhered on a mount base 54 made of Kovar. The mount base 54 has a columnar convex portion 54a on the lower surface corresponding to the concave infrared detecting element mounting portion 41b. An alignment mark (not shown) is formed on the mount base 54 with reference to the projection 54a, and an alignment mark (not shown) is also formed on the sapphire substrate 52. The substrate 52 and the mounting table 54 are bonded by using a jig utilizing enlarged projection so that the positioning mark of the sapphire substrate 51 and the positioning mark of the mounting table 54 are aligned. Therefore, the mounting table 5
The center 03 of the projection 54a and the center 04 of the infrared detecting element 45 are accurately located on the center line CL2 of the mount table 54.

On the surface of the concave infrared detecting element mounting portion 41b, for example, silicone rubber or araldite of a mold 6-1140 manufactured by Dow Corning Co., Ltd. is applied to form a silicone rubber film 55. The convex portion 53a is fitted to the concave infrared detecting element mounting portion 41b and bonded with a silicone rubber film (or an araldite film) 55, so that the infrared detecting element assembly 50 is attached to the infrared detecting element mounting portion 41b.
It is attached to. Thereby, the infrared detecting element 45
Are attached to the infrared detecting element attaching portion 41b.

The fitting accuracy between the convex portion 53a and the concave infrared detecting element mounting portion 41b is high. Therefore, the center 04 of the infrared detecting element 45 is accurately located on the center line CL1 of the container main body 41 in a state where the infrared detecting element 45 is mounted on the infrared detecting element mounting portion 41b. Here, silicone rubber and araldite, which are adhesives, are applied sufficiently thin, and the film thickness is negligible (about 1 μm).

The vacuum vessel 40 containing the infrared detecting element is shown in FIG.
As shown in the figure, the base portion 41c is fitted to and fitted to the concave mounting portion 61 of the search device main body 60. Therefore,
The fitting accuracy between the base portion 41c and the mounting portion 61 is high.
Therefore, the vacuum chamber 40 containing the infrared detecting element is attached to the mounting portion 6.
The center 04 of the infrared detecting element 45 is accurately located on the center line CL3 of the search device main body 60 in a state where the infrared detecting element 45 is fitted and mounted on the main body 1. Also, the surface S3 of the infrared detecting element 45
The parallelism of the mounting portion 61 with respect to the surface S4 also has good accuracy. Therefore, subsequent position adjustment is unnecessary. Therefore, the assembling work of the search device 63 can be performed efficiently.

The cooling head 17 is connected to the inner cylindrical portion 41.
a, and the top of the cooling head 17 is thermally conductive with the lower surface of the infrared detecting element mounting portion 41b. The search device 63 operates the cooling device 13, that is,
The compressor 15 is started to operate the expander 16, the cooling head 17 is cooled according to the principle of the reverse Stirling cycle, and the infrared detecting element 11 is operated in a state where it is cooled to an extremely low temperature.

The thickness t1 of the inner cylindrical portion 41a is 0.1
mm, and the thickness t2 (1 m
m), which is as thin as one tenth. Therefore, the thermal conductivity of Kovar is 1.3 × 10 ⁻¹ W / cm · deg, which is about 18 times higher than the thermal conductivity of glass of 7.2 × 10 ⁻³ W / cm · deg. The resistance to heat conduction along the cylindrical portion 41a is sufficiently high. Therefore, cooling of the infrared detecting element is performed efficiently and with low power consumption.

Further, the size of the infrared detecting element 45 has become larger than before due to an increase in the number of pixels, and accordingly, the diameter D1 of the inner cylindrical portion 41a has become larger than before. However, since the thickness t1 of the inner cylinder portion 41a is as thin as 0.1 mm, even if the diameter D1 increases, the heat capacity of the inner cylinder portion 41a does not increase so much. This also allows the infrared detecting element to be cooled efficiently and with low power consumption.

Further, the container body 41 is composed of one part as shown in FIG.
Are replaced with a plurality of components as shown in FIG. 5, and the vacuum vessel 40 for housing the infrared detecting element is configured with a smaller number of components compared to the related art. Next, the configuration of a portion other than the above-described configuration in the vacuum chamber 40 that contains the infrared detecting element will be described.

The wiring board 43 is made of ceramic and fixed to the upper surface of the getter case portion 41d of the container body 41 by brazing. 65 is a brazing part. The outer cylinder 42 is
The inner tubular portion 41a is covered and welded to the wiring board 43. 6
Reference numeral 6 denotes a weld. The outer cylinder 42 has a window 67. A cold shield 47 is provided to cover the infrared detecting element 45.

The flexible cable 46 is connected to the inner cylinder 41
The wiring is provided between the top of the line a and the wiring board 43. The output of the infrared detecting element 45 passes through the flexible cable 46 and the pattern of the wiring board 43, and passes through a terminal 6 outside the vacuum space 44.
7 The structure of the flexible cable 46 will be described later. A getter 48 is provided in the getter case portion 41d, and the getter 48 absorbs gas generated in the vacuum chamber 40 containing the infrared detecting element.

The reason why the substrate 52 is made of sapphire is that the coefficient of thermal expansion of sapphire is close to the coefficient of thermal expansion of silicon as the material of the infrared detecting element 45. The reason why the mount base 54 and the container body 41 are made of Kovar is as follows.
This is because the thermal expansion coefficient of Kovar is close to the thermal expansion coefficient of sapphire, which is the material of the substrate 52, the price is reasonable, and the cutting process is possible.

Next, the processing of the container body 41 will be described. The container main body 41 is manufactured by chucking the Kovar round bar material 70 of FIG. 4A using a precision lathe and processing it to the end without removing the chucking on the way without removing the chucking. . The material 70 is a getter case portion 41
It is a cylinder processed to the same diameter as the outer diameter of d with high precision.

First, as shown in FIG.
Cut out the outside of 1a. Next, as shown in FIG. 4C, the inside of the inner cylindrical portion 41a is cut out. At this time, as for the thickness of the inner cylinder 41a, a minimum thickness (for example, 1 mm) having a strength enough to normally process the infrared detecting element mounting portion 41b at the tip of the inner cylinder 41a is left. Next, FIG.
As shown in (D), the tip of the inner cylinder portion 41a is cut,
An infrared detecting element mounting portion 41b is formed.

Next, as shown in FIG. 4E, the getter case portion 41d is cut out, and subsequently, the base portion 41c is cut out. In this state, the center of the cut-out infrared sensing element mounting portion 41b and the center of the cut-out base portion 41c are accurately positioned. Finally, FIG.
As shown in the figure, the outer peripheral surface of the inner cylindrical portion 41a is polished, and the thickness of the inner cylindrical portion 41a is gradually reduced to 0.1 mm. Thus, the container body 41 is completed.

Here, the accuracy of the surface of the inner cylindrical portion 41a does not matter. This is because even if the outer peripheral surface of the inner cylindrical portion 41a is polished, the accuracy of the center of the cut-out infrared detecting element mounting portion 41b and the center of the cut-out base portion 41c is not affected. 5 (A) to 5 (C) show a procedure of assembling the vacuum vessel 40 containing the infrared detecting element.

First, as shown in FIG. 5A, the getter 48 is placed in the getter case 41d, and the wiring board 43 is fixed to the container body 41 by brazing on the upper surface of the getter case 41d. Next, as shown in FIG. 5B, the infrared detecting element assembly 50 is attached to the infrared detecting element mounting portion 41b, and the flexible cable 46 is stretched.

Next, as shown in FIG.
2 is fixed to the wiring board 43 by welding so as to cover the inner cylindrical portion 41a. Finally, the air in the internal space is evacuated to complete the vacuum vessel 40 containing the infrared detecting element. Next, the flexible cable 46 will be described. The flexible cable 46 has a structure in which the inner cylindrical portion 41a is made of metal and the inner cylindrical portion 41a is made of metal.
This is provided because a wiring pattern cannot be formed on the peripheral surface of a. Here, the flexible cable 46
Is a structure in consideration of wiring in the vacuum space 44.

As shown in FIG. 6, the flexible cable 46 has a 7 μm thick copper thin film wiring pattern 81 on one side of a 30 μm thick polyimide base 80.
Each wiring pattern 81 is attached without an adhesive.
It is configured to be covered with the u thin film 82. There is no cover that covers the wiring pattern of a normal flexible cable.
Therefore, the flexible cable 46 does not generate gas.

The upper end of the flexible cable 46 is made of an adhesive (trade name: Castor, model E-1520 / RT).
7) It is adhered to the top of the inner cylinder portion 41a by 85. The amount of adhesive is kept to a minimum and gas generation is suppressed. Here, the vibration is not a problem because the flexible cable 46 has a small mass.

Further, instead of the material 70 shown in FIG. 4A, a material 90 shown in FIG. 7 may be used. The material 90 has a structure including an outer peripheral portion 91 made of Kovar and a central portion 92 made of Inconel or stainless steel. When this material 90 is used, the inner cylinder part of the completed container body is made of Inconel or stainless steel, and the getter case part and the base part are made of Kovar. Inconel or stainless steel has higher rigidity than Kovar, and is therefore advantageous in reducing the thickness of the inner cylinder.

The material 90 may be formed by press-fitting an Inconel or stainless steel cylinder into a Kovar cylinder, or by combining a Kovar cylinder with an Inconel or stainless steel cylinder inserted therein. It is manufactured by attaching. In addition, the element accommodated in the vacuum container is not limited to the infrared detection element, and may be any photoelectric conversion element that requires cooling.

[0037]

As described above, according to the first aspect of the present invention, the container body integrally has the inner cylinder portion formed by cutting and shaving a material and the base portion, Since the photoelectric conversion element assembly having the photoelectric conversion element assembly having the photoelectric conversion element is fitted and mounted on the top of the part, the photoelectric conversion element mounting part is mounted on the photoelectric conversion element mounting part with respect to the base part. Position accuracy can be improved, so that position adjustment after fitting and mounting the vacuum vessel to the apparatus body can be eliminated.

Further, since the inner cylindrical portion has a thickness small enough to maintain the strength, the thermal resistance is high, so that the photoelectric conversion element can be efficiently cooled. According to the second aspect of the present invention, the flexible cable has a structure in which a wiring pattern made of a copper thin film is adhered on a base made of a synthetic resin having flexibility without using an adhesive. Without
Therefore, it is possible to prevent the degree of vacuum in the vacuum space from deteriorating.

[Brief description of the drawings]

FIG. 1 is a view showing a vacuum container accommodating an infrared detecting element according to an embodiment of the present invention.

FIG. 2 is a view showing a container main body in FIG.

FIG. 3 is an enlarged view showing a mounting portion of the infrared detecting element in FIG. 1;

FIG. 4 is a view for explaining the production of the container main body of FIG. 2;

FIG. 5 is a view for explaining the assembly of the vacuum vessel containing the infrared detecting element shown in FIG. 1;

FIG. 6 is a sectional view of a flexible cable in FIG.

FIG. 7 is a view showing a modification of the material shown in FIG.

FIG. 8 is a diagram showing a configuration of a general search device.

FIG. 9 is a view showing a conventional vacuum vessel containing an infrared detecting element.

FIG. 10 is a view showing a structure of an inner cylinder in FIG. 9;

[Explanation of symbols]

 Reference Signs List 40 Vacuum container containing infrared detecting element 41 Container main body 41a Inner cylinder part 41b Concave infrared detecting element mounting part 41c Base part 41d Getter case part 42 Outer cylinder 43 Wiring board 44 Vacuum space 45 Infrared detecting element 46 Flexible cable 47 Cold shield 48 Getter REFERENCE SIGNS LIST 50 Infrared detecting element assembly 51 In-made bump 52 Sapphire substrate 53 In-made adhesive sheet 54 Mount table 54 a Convex part 60 Searching device main body 61 Recessed mounting portion 62 Searching device

Claims (2)

[Claims] An inner cylinder, an outer cylinder covering the inner cylinder, and a photoelectric conversion element requiring cooling attached to a top of the inner cylinder, wherein the photoelectric conversion element is provided. A vacuum chamber having a vacuum space between the inner cylinder and the outer cylinder, wherein the inner cylinder portion and the base portion formed by cutting and shaving a material are provided. A photoelectric conversion element mounting portion to which a photoelectric conversion element assembly having the photoelectric conversion element is fitted and mounted on the top of the inner cylindrical portion, and the inner cylindrical portion has strength enough to maintain strength. A container body having a small thickness, wherein the photoelectric conversion element assembly is fitted and attached to the photoelectric conversion element mounting portion, and the photoelectric conversion element housing vacuum container is provided with the base portion of the container body. A configuration in which the device is fitted to the device main body and fitted to the device main body. A vacuum container containing a photoelectric conversion element. 2. A flexible cable having a structure in which a wiring pattern made of a copper thin film is applied on a base made of a synthetic resin having flexibility without using an adhesive, in order to extract the output of the photoelectric conversion element, 2. The vacuum container for accommodating a photoelectric conversion element according to claim 1, wherein the vacuum container is configured to be wired and provided in the vacuum space.