JPH09320493A - Vacuum air-tight container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum air-tight container which can retain high vacuum degree even if baking process is carried out by housing a first getter having a normal temperature operational region and a second getter having the temperature at the time of baking as the operational region. SOLUTION: A rectangular getter box 4 in which a first getter 7-1 and a second getter 7-2 are housed is fixed in a first substrate 2 by a seal member 8 and a housing space of a display part constituted of the substrate 2 and a second substrate 3 and a box 4 are mutually communicated through a through hole 6 formed in a through hole piece 9. The getter 7-1 made of a Ba-Al alloy exhibits sufficient getter function at a normal temperature and decreased by half at the time of baking at about 200-250 deg.C. A stored gas in the container is therefore adsorbed by the getter 7-2 such as a Ceto getter at the time of baking and by the getter 7-1 when the temperature becomes a normal temperature and consequently, high vacuum degree of the inside of the vacuum container 1 can be retained for a long duration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum airtight container that holds a vacuum inside.

[0002]

2. Description of the Related Art Conventionally, there is known a fluorescent display device comprising a field emission cathode known as a planar cold cathode and an anode on which a phosphor for collecting electrons emitted from the field emission cathode is attached. Have been. In this fluorescent display device, the cathode and the anode are arranged at a very small distance from each other, but since the space therebetween is a space, the cathode and the anode are housed in a vacuum-tight container. By the way, when the cathode and the anode are operating, the minute gas stored inside is released, which pollutes the inside and reduces the degree of vacuum. A getter that keeps the material clean and vacuum is generally provided in the vacuum airtight container.

[0003]

As a material for a getter provided in a vacuum airtight container, an evaporation type getter using a Ba-Al alloy as a getter material is usually used.
This Ba-Al alloy is housed in a ring-shaped metal member and sealed in a vacuum airtight container, and the ring-shaped portion is induction-heated from the outside by a high frequency.
The Al alloy is evaporated and deposited on the inner wall surface of the vacuum airtight container. This vapor-deposited film is called a getter mirror because it looks like a mirror. By the way, in the fluorescent display tube, after the getter material is evaporated, in order to activate the getter, the fluorescent display tube is put in an oven at 200 ° C. or higher to perform a baking process. At this time, the gas occluded in the tube is released, and this occluded gas must be adsorbed by a getter to further increase the degree of vacuum in the tube.

However, the Ba--Al alloy has a temperature of 200.degree.
At temperatures in between, the cleaning action is somewhat increased, but gas is released from the barium film, or barium reacts with the glass and changes. Further, if the temperature is 200 ° C. or higher, recrystallization will occur, so that the saturated adsorption amount of the getter mirror will decrease even if the temperature is returned to room temperature. Therefore, it is difficult to maintain a sufficiently high vacuum inside the vacuum hermetic container.

Therefore, an object of the present invention is to provide a vacuum airtight container provided with a getter capable of maintaining a high vacuum inside even if a baking process is performed.

[0006]

In order to achieve the above object, the vacuum airtight container of the present invention has a first getter made of a getter material which operates at room temperature as an operating region, and a temperature during baking within the operating region. The second getter made of the getter material is said to be housed inside. As a result, the stored gas in the tube can be adsorbed by the second getter operating at this temperature during baking, so that the saturated adsorption amount of the first getter can have a margin when the temperature is returned to room temperature. Therefore, the degree of vacuum in the tube can be maintained at a sufficiently high vacuum.

According to the present invention, in the vacuum airtight container, the first getter is an evaporation getter containing at least Ba, or the second getter is Z.
The non-evaporable getter contains at least any one of r, Ti, Ta, Th, and Cb, and the second getter is a porous substance containing at least C. Furthermore, the second getter may be an evaporation getter containing at least Mg.

[0008]

1 and 2 show an example of the configuration of an embodiment of a vacuum airtight container of the present invention. FIG. 1 is a top view when a vacuum airtight container is applied to a fluorescent display tube, and FIG. 2 is a sectional view taken along the line AA. FIG.
As shown in FIG. 2 and FIG.
The second substrate 3 and the second substrate 3 are arranged so as to face each other with a minute gap, and a seal member 8 seals between them. The first substrate 2 and the second substrate 3 are, for example, glass substrates,
A planar field emission cathode group is formed on the first substrate 2, and an anode on which a phosphor is adhered is formed on the second substrate 3. The first substrate 2 and the second substrate are fixed by a seal member 8 with a distance of about 200 μm to 500 μm.

The first substrate 2 and the second substrate 3 are arranged so as to face each other with a slight shift in the longitudinal direction, and the first substrate 2 is formed slightly larger than the second substrate 3 as shown in the drawing. , Their three sides project outward from the second substrate 3. The second substrate 3 projects on the remaining one side. A rectangular getter box 4 accommodating the first getter 7-1 and the second getter 7-2 inside is fixed on the first substrate 2 by a seal member 8 so as to cover the protruding portion of the second substrate 3. Has been done. Further, a communication hole 6 is formed between the projecting second substrate 3 and the getter box 4, and a rectangular communication hole piece 9 is fixed to the side surface of the first substrate 2. The hole piece 9 is further fixed between the second substrate 3 and the getter box 4 by the seal member 8. The communication hole 6 formed in the communication hole piece 9 is a hole for communicating the space in which the display portion formed by the first substrate 2 and the second substrate 3 is housed with the inside of the getter box 4. .

An exhaust pipe 5 is welded to the upper surface of the getter box 4, and a hole which connects the exhaust pipe 5 and the inside of the getter box 4 is formed in the upper surface of the getter box 4. In addition, the first getter 7 is provided in the getter box 4.
-1 and the second getter 7-2 are stored, but the first
The getter 7-1 is B housed in a ring-shaped metal member.
It is an evaporation type getter using an a-Al alloy as a getter material. Then, the Ba-Al alloy is heated and evaporated by induction heating of the ring-shaped portion from the outside by high frequency, and is deposited on the inner wall surface of the getter box 4. This vapor-deposited film is called a getter mirror because it looks like a mirror.

The getter mirror is formed by positioning the first substrate 2 on which the field emission cathode is formed and the second substrate 3 on which the anode coated with the phosphor is formed and sealing member 8. The vacuum airtight container 1 is formed by sealing with the above, and while the gas is discharged, the inside of the vacuum airtight container 1 is evacuated to seal the exhaust pipe 5, and then the first getter 7-1 is evaporated to obtain a getter mirror. Is formed. After forming the getter mirror, the vacuum airtight container 1 is placed in a furnace and a baking process is performed to activate the getter. The baking temperature is about 200 ° C. to 250 ° C., but the gas stored in the vacuum airtight container 1 and released at this time is adsorbed by the second getter 7-2.

The second getter 7-2 is a Zr-based non-evaporable getter, a Ceto (80% Th, 20% Al-Ce alloy) getter, a getter composed of a porous material layer such as carborundum, and a Mg-based evaporative getter. Any of these can be used, and it has a sufficient getter ability even at the time of baking at about 200 ° C to 250 ° C. Moreover, as described above, the first getter 7 made of a Ba—Al alloy is used.
-1 has a sufficient getter ability at room temperature, but its ability is halved during baking. Therefore, in the present invention, as described above, the gas absorbed by the second getter 7-2 is adsorbed by the second getter 7-2, and the gas is absorbed by the first getter 7-1 when the temperature is returned to room temperature. It is designed to absorb the gas that is being generated. Therefore, the inside of the vacuum airtight container 1 can be maintained in a high vacuum for a long period of time. In addition, B
It seems that it is sufficient to increase the amount of the first getter 7-1 made of a-Al alloy, but the first getter 7-1 made of Ba-Al alloy is used.
When the amount of the getter 7-1 is increased, a large amount of gas is generated during the evaporation, which may contaminate the inside of the vacuum airtight container 1. Therefore, the first getter 7-1 made of a Ba—Al alloy is used.
The amount of can not be increased.

Next, the structure of a modified example of the vacuum hermetic container of the present invention is shown in FIG. In the modification shown in FIG. 3, two getter boxes are provided as shown in the drawing, and different getters are housed in the respective getter boxes. In FIG. 3, similar to the vacuum airtight container 1 shown in FIG. 1, the vacuum airtight container 1 includes a first substrate 2 and a second substrate 3.
Are arranged so as to face each other with a minute gap therebetween, and the space between them is sealed by a seal member. First substrate 2 and second
The substrate 3 is made of, for example, a glass substrate, a flat field emission cathode group is formed on the first substrate 2, and an anode coated with a phosphor is formed on the second substrate 3. The first substrate 2 and the second substrate are about 200 μm to 5 μm.
It is fixed by a seal member 8 at a distance of 00 μm.

Further, the first substrate 2 and the second substrate 3 are arranged so as to face each other with a slight shift in the diagonal direction, and as shown in the figure, the first substrate 2 and the second substrate 3 are formed to have substantially the same size. Therefore, the two sides of each of the two protrude from the mutual substrates to the outside. Then, a rectangular getter box 4A for accommodating the first getter 7-1 therein and a second getter 7-2 inside so as to cover the protruding portion of the second substrate 3.
A getter box 4B having a rectangular shape that accommodates is fixed on the first substrate 2 by a seal member. Further, rectangular communication hole pieces in which communication holes 6A and 6B are formed between the protruding second substrate 3 and getter boxes 4A and 4B are the same as those shown in FIG. The communication hole piece is further fixed between the second substrate 3 and the getter boxes 4A, 4B by a seal member. The communication holes 6A and 6B formed in the communication hole pieces are for communicating the space in which the display portion formed by the first substrate 2 and the second substrate 3 is housed with the inside of the getter boxes 4A and 4B. It is a hole.

Exhaust pipes 5A and 5B are welded to the upper surfaces of the getter boxes 4A and 4B, and holes for communicating the exhaust pipes 5A and 5B with the inside of the getter boxes 4A and 4B are formed in the upper surfaces of the getter boxes 4A and 4B. Has been done. A first getter 7-1 is housed in the getter box 4A, and the first getter 7-1 is an evaporation type getter using a Ba-Al alloy housed in a ring-shaped metal member as a getter material. Has been done. Then, the ring-shaped portion is induction-heated from the outside by a high frequency, so that B
The a-Al alloy is heated and evaporated, and the getter box 4
It is vapor-deposited on the inner wall surface of A. Further, the second getter 7-2 is stored in the getter box 4B,
The getter 7-2 is a Zr-based non-evaporable getter, Ceto (8
Any of a 0% Th, 20% Al-Ce alloy) getter, a getter made of a porous material layer such as carborundum, and a Mg-based evaporation getter can be used, and the temperature is about 200 ° C.
It has a sufficient getter ability even during baking at 250 ° C.

Therefore, also in the modified example, the gas stored in the tube is adsorbed by the second getter 7-2 housed in the getter box 4B at the time of baking, and inside the getter box 4A when the temperature is returned to room temperature. The getter mirror of the first getter 7-1 formed on the wall surface of the above is adapted to adsorb the gas stored in the tube. Therefore, the inside of the vacuum airtight container 1 can be maintained in a high vacuum for a long period of time. In the modified example, the second
Even if the getter 7-2 is an evaporation type getter, since both getters are arranged independently, the getter mirrors of both getters do not overlap. Therefore, each getter can be efficiently operated. Further, even if the getter stored in the getter box 4A is the second getter 7-2, the getter stored in the getter box 4B is the first getter 7-2.
It may be -1.

[0017]

Since the present invention is constructed as described above, since the second getter which operates sufficiently at this temperature can adsorb the stored gas in the tube during baking, the first getter when the temperature is returned to room temperature. It is possible to give a margin to the saturated adsorption amount of the getter. Therefore, the degree of vacuum in the tube can be maintained at a sufficiently high vacuum for a long period of time.

[Brief description of drawings]

FIG. 1 is a top view showing a configuration of an embodiment of a vacuum hermetic container of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of an embodiment of a vacuum hermetic container of the present invention.

FIG. 3 is a top view showing a configuration of a modified example of the embodiment of the vacuum hermetic container of the present invention.

[Explanation of symbols]

 1 Vacuum Airtight Container 2 1st Substrate 3 2nd Substrate 4, 4A, 4B Getter Box 5, 5A, 5B Exhaust Pipe 6, 6A, 6B Communication Hole 7-1, 7-2 Getter 8 Sealing Member 9 Communication Hole Piece

Claims (5)

[Claims] 1. A first getter made of a getter material that operates at room temperature as an operating region, and a second getter made of a getter material that has a baking temperature within the operating region are housed inside. A vacuum airtight container characterized in that 2. The vacuum hermetic container according to claim 1, wherein the first getter is an evaporation getter containing at least Ba. 3. The second getter is Zr, Ti, T
3. A non-evaporable getter containing at least any of a, Th, and Cb.
The vacuum-tight container described. 4. The vacuum hermetic container according to claim 1 or 2, wherein the second getter is made of a porous material containing at least C. 5. The vacuum hermetic container according to claim 1 or 2, wherein the second getter is an evaporation getter containing at least Mg.