JP2001195976A - Getter device for electron tube and method of the same, and electron tube using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a getter device for electron tube, in which the quality and reliability of the electron tube are improved by using a getter device which substantially controls an ion shock to a large-sized electron tube or CDT using, for example, an impregnation type cathode. SOLUTION: This getter device is a getter device for electron tube having getter material including a Ba-Al alloy powder and an Ni powder filled in a metallic getter vessel. The getter material has partial pressures of argon and nitrogen of 10-5 Pa or below in a gas released during getter flashing. Also, the partial pressure of a carbon-containing gas in the gas released during getter flashing is set up at 10-3 Pa or below. After filling into the metallic getter vessel, the getter material is previously subjected to high-frequency induction heating in vacuo for 30 seconds or shorter at a temperature of 700 to 800 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention relates to an electron tube getter device used for T (electron tube for color display) and the like, a method of manufacturing the same, and an electron tube using the same.

2. Description of the Related Art Recently, for example, in the field of consumer televisions, large-sized televisions of about 32 inches to 37 inches have become widespread. In a large electron tube used for such a large television, an electron tube for a color display (CDT), and the like, high definition and high resolution are being promoted in order to satisfy high quality. For this reason, electron tubes (cathode ray tubes) used for large televisions, CDTs and the like are required to have high performance, and one of them is to increase the removal rate of gas components in the electron tubes.

[0002] A getter device is generally used to remove unnecessary oxidizing gas and the like remaining in an electron tube after exhaust. The getter device is obtained by filling a getter container made of a mixed powder of a Ba-Al alloy powder and a Ni powder in a metal getter container made of stainless steel or the like. It is arranged at a predetermined position. Then, Ba is applied by external heating such as high-frequency induction heating.
Is vaporized (getter flash) to form a getter film of Ba on the inner wall of the tube.

In recent electronic tubes for large televisions and CDTs as described above, an impregnated cathode having a high current density has been used in place of an oxide cathode in order to increase the resolution. ing. But,
The impregnated cathode is vulnerable to ion bombardment, so there was no problem when using an oxide cathode. Ar and N ₂ in the air component emitted during getter flash and methane generated during flash have an adverse effect. Is becoming apparent.

In a conventional getter device, usually, after a getter material is filled in a getter container, the getter material is heated to 350 to 520 ° C. in a vacuum.
By heating to about the temperature, the removal process of the gas component from the getter material is performed. However, high-quality electronic tubes and CDs for large televisions using impregnated cathodes
For T, etc., the conventional gas component removal treatment process is not enough. To reduce the ion bombardment by gas, it is necessary to take a long time to carry out an electronic tube for large TV or C
Although DT and the like are manufactured, the suppression of ion bombardment on the impregnated cathode is not perfect, and a small amount of ion bombardment causes a phenomenon such that electron emission partially stops.

[0005]

As described above, impregnated cathodes have come to be used in large electron tubes, CDTs, etc., which have recently been required to have high quality. In order to reduce the ion bombardment on such an impregnated cathode, conventionally, measures such as prolonging the process have been taken, but since the suppression of ion bombardment is not perfect,
The getter device itself is required to reduce ion impact.

SUMMARY OF THE INVENTION The present invention has been made to address such a problem, and has, for example, a getter device for an electron tube which is capable of essentially suppressing ion bombardment of a large electron tube or a CDT using an impregnated cathode. It is an object of the present invention to provide an electron tube with improved quality and reliability by using such a getter device and a method for manufacturing the same.

[0007]

According to a first aspect of the present invention, there is provided a getter device for an electron tube, comprising: a getter container made of metal; and a Ba-Al alloy powder and a Ni powder filled in the getter container. Wherein the getter material has a partial pressure of 10 ⁻⁵ of argon and nitrogen in the gas released at the time of getter flash.
It is characterized by being less than Pa.

In the getter device for an electron tube according to the present invention, the getter material has a partial pressure of 10 ^-3 Pa or less of a carbon-containing gas component in a gas released at the time of the getter flash. It is characterized by having.

According to another aspect of the present invention, there is provided a getter device for a metal tube, a getter container made of metal, and a getter container filled in the getter container and containing a Ba-Al alloy powder and a Ni powder. In the getter device for an electron tube, the getter material is subjected to high-frequency induction heating in a vacuum at a temperature of 700 to 800 ° C. for 30 seconds or less.

Further, according to a fourth aspect of the present invention, there is provided a method of manufacturing a getter device for an electron tube, comprising the steps of: filling a getter material containing a Ba-Al alloy powder and a Ni powder into a getter container; Subjecting the getter material filled in the getter container to high-frequency induction heating in a vacuum at a temperature of 700 to 800 ° C. for 30 seconds or less.

According to a seventh aspect of the present invention, there is provided an electron tube including the above-described getter device for an electron tube according to the present invention. As described in claim 8, the electron tube of the present invention is particularly effective for a cathode ray tube for a large television and a cathode ray tube for a color display.

According to the getter device for an electron tube of the present invention, the amount of unnecessary gas components in the gas released from the getter material at the time of getter flush, that is, by subjecting the getter material to high-frequency heating for a short time as a gas releasing step, that is, The amount of argon and nitrogen, and the amount of carbon-containing gas components are greatly reduced. According to such a getter device, it is possible to perform a getter flush satisfactorily without substantially adversely affecting the impregnated cathode in the same process time as the conventional oxide cathode. That is, it is possible to prevent poor electron emission of the impregnated cathode due to ion bombardment. Accordingly, the quality and reliability of a cathode ray tube for a large television or a color display having an impregnated cathode can be greatly improved.

[0013]

Embodiments of the present invention will be described below.

FIG. 1 is a sectional view showing a getter device for an electron tube according to an embodiment of the present invention. A getter device 1 shown in FIG. 1 is configured by filling a getter material 3 in a getter container 2 having an open end and an annular inner wall. The getter container 2 is made of, for example, a metal member such as stainless steel, and the getter material 3 is pressurized and filled in the getter container 2 by a press device or the like.

The getter material 3 contains, for example, 40 to 60% by mass of B
A mixed powder of a-Al alloy powder and 60 to 40% by mass of Ni powder is used. Also, if necessary, getter material 3
Nitride powder such as iron nitride powder of 2.0% by mass or less
0.2% by mass or less of boron oxide powder or the like may be added.

As the Ba-Al alloy powder in the getter material 3, for example, a BaAl ₄ alloy is used. Ba-
In order to reduce the amount of unnecessary emission gas at the time of getter flash, it is necessary to use an Al alloy powder having a low content of impurity elements which are gas components such as carbon, oxygen, and air components (nitrogen, argon, etc.). preferable. Specifically, it is preferable to use a Ba-Al alloy powder having a total content of these impurity gas component elements of 0.2% by mass or less. The individual contents of carbon, oxygen, and air components (nitrogen, argon, etc.) are 0.02% by mass or less for carbon and 0.1% for oxygen.
It is preferable that the content be 15% by mass or less and the air component be 0.01% by mass or less. The average particle diameter of the Ba-Al alloy powder is 150 μm in order to improve the reactivity.
The following is preferred.

On the other hand, the Ni powder in the getter material 3 is preferably subjected to, for example, a high-temperature reduction treatment in order to reduce the amount of released gas. The high-temperature reduction treatment applied to the Ni powder is preferably performed in a reducing atmosphere such as an H ₂ atmosphere at a temperature of 400 to 600 ° C. for 2 to 4 hours. According to such a high-temperature reduction treatment,
The amount of the impurity gas component in the Ni powder can be efficiently reduced. In particular, the amount of carbon that causes the formation of carbon compounds (carbon-containing gas components) such as CO, CO ₂ , and CH ₄ can be sufficiently reduced.

The amount of the impurity gas component in the Ni powder is 0.1 mass
% Or less, and particularly preferably the carbon content is 0.02% by mass or less. The average particle diameter of the Ni powder is preferably 35 μm or less in consideration of the mixing property with the Ba—Al alloy powder. However, if the particle size of the Ni powder is too small, the scattered Ba particles may become coarse and the uniformity of the getter film may be impaired. Therefore, the average particle size of the Ni powder is preferably 10 μm or more.

Further, the getter material 3 may be used by granulating at least a part of the Ba-Al alloy powder and Ni powder in order to uniformly generate the reaction. In such a case, the relatively fine powder in the Ba-Al alloy powder and N 2
It is preferable to use granulated i powder.

The above-mentioned Ba-Al alloy powder and Ni
When the getter material 3 containing the powder is filled in the getter container 2, the partial pressure of argon and nitrogen in the gas released at the time of getter flush, that is, the partial pressure of the air component becomes 10%.
^-5 Pa or less. Further, the carbon-containing gas component in the gas released during the getter flash, that is, CO,
10 ^{-3 for the} partial pressure of carbon compounds such as CO ₂ and CH ₄
Pa or less.

In order to satisfy the amount of gas component (partial pressure of gas component) released at the time of getter flash,
In the present invention, after the getter material 3 containing the Ba-Al alloy powder and the Ni powder is filled in the getter container 2, the getter material 3 is subjected to 700 to 800 ° C. in a vacuum as a gas discharging step.
Perform high-frequency induction heating at a temperature of 30 seconds or less. According to the high-frequency induction heating, since the getter material 3 is directly heated, unnecessary gas components contained in the getter material 3, that is, air components such as argon (Ar) and nitrogen (N ₂ ) are sufficiently removed. It can be removed. In addition, CO and CO ₂
Carbon oxides such as, and hydrocarbons such as CH ₄ can be similarly sufficiently removed.

The temperature during high-frequency induction heating is in the range of 700 to 800 ° C. as described above. As shown in FIG. 2, if the temperature during the high-frequency induction heating is lower than 700 ° C., it is not possible to sufficiently remove unnecessary gas components from the getter material 3 in a short time. On the other hand, if the temperature at the time of high-frequency induction heating exceeds 800 ° C., getter flash may occur, and the performance of the getter material 3 will be reduced.

The high-frequency induction heating time is 30 seconds or less. As shown in FIG. 3, when the high-frequency induction heating time exceeds 30 seconds, getter flash may occur. The high-frequency induction heating time is more preferably in the range of 10 to 15 seconds. With such high-frequency induction heating for a short time, the getter material 3 can be used without deteriorating the original performance of the getter material 3.
Unnecessary gas components can be sufficiently removed from the gas.

As described above, the degassing step in the present invention is a step of high-frequency induction heating of the getter material 3 in such a short time that no getter flash occurs. In a conventional vacuum
In the heat treatment (vacuum heat treatment) at a temperature of about 350 to 520 ° C., the entire getter material 3 is heated to a predetermined temperature, kept at that temperature for a certain period of time, and then gradually cooled. In addition to being sufficient, there is a possibility that the gas component released in the cooling step may be re-adsorbed. On the other hand, according to the high-frequency induction heating according to the present invention, the getter material 3 can be directly heated to a high temperature in a short time, so that the gas release property can be sufficiently improved and the released gas can be increased. Re-adsorption of components can be prevented.

Therefore, according to the degassing process of the present invention,
The amount of unnecessary gas components released from the getter material 3 at the time of getter flash can be greatly reduced. Specifically, the partial pressures of argon and nitrogen in the gas released from the getter material 3 at the time of getter flash are adjusted with good reproducibility to 10 ^-5.
Pa or less. Further, the carbon-containing gas component in the gas released at the time of getter flash can be reduced to 10 ⁻³ Pa or less with good reproducibility.

As described above, in the getter device 1 of the present invention, the amount of air components (such as the amount of argon and the amount of nitrogen) released from the getter material 3 at the time of getter flush,
Ar, N ₂ , CO, C, which adversely affect the amount of carbon-containing gas components such as O, CO ₂ and CH ₄ generated during getter flash, in other words, impregnated cathodes and the like.
The release amount of O ₂ , CH _4, etc. is sufficiently reduced in advance.
Therefore, by using the getter device 1 having such a getter material 3, the getter flush can be satisfactorily performed without adversely affecting the impregnated cathode in the same process time as the conventional oxide cathode. It becomes possible.

That is, the ion bombardment of the impregnated cathode with Ar, N ₂ , CO, CO ₂ , CH _4, etc. caused by getter flash can be essentially suppressed. Therefore, it is possible to prevent the occurrence of electron emission failure due to the ion bombardment of the impregnated cathode. As described above, by using the getter device of the present invention, the quality and reliability of a cathode ray tube for a large television or a cathode ray tube for a color display (CDT) having an impregnated cathode can be shortened. Can be enhanced.

The electron tube of the present invention is provided with the getter device 1 of the present invention as described above, and is particularly effective for a color cathode ray tube having an impregnated cathode. Specifically, for example, it is effective for a color cathode ray tube for a large television of 30 inches or more, a CDT, or the like.
Here, when used for a large electron tube, for example, the scattering amount of Ba is 300 to 350 mg and the filling amount of the getter material 3 is 1300 to 1500.
A getter device such as mg is preferred.

[0029]

Next, specific examples of the present invention will be described.

Example 1 1100 mg of a getter material containing 46.5% by mass of Ba-Al alloy powder, 52.5% by mass of Ni powder and 1.0% by mass of iron nitride powder was placed on one end of an outer diameter of 20 mm, an inner diameter of 8.5 mm and a height of 2.5 mm. Was opened and the getter container 2 made of stainless steel and having an annular inner wall shown in FIG. 1 was filled at a predetermined density using a press device.

Among the above getter materials, Ba-Al alloy powder having an average particle diameter of 100 μm is used.
The powder used had an average particle diameter of 20 μm. And after the getter material 3 containing such Ba-Al alloy powder and Ni powder is filled in the getter container 2 made of stainless steel,
By high frequency induction heating of frequency 250kHz, getter material 3
Degassing was performed in a vacuum of 10 ^-2 Pa at 700 ° C for 10 seconds.

The getter device thus obtained was mounted in a color cathode ray tube having a 17-inch CDT impregnated cathode and heated externally by a high frequency generator to perform getter flash. At this time, the total heating time was set to be constant at 30 seconds, and the amount of Ba scattered was measured. As a result, 230 mg of Ba scattered at a flash start time of 10 seconds could be realized.

Further, the partial pressure of Ar, the partial pressure of N ₂ , CO and C
The partial pressure of O _{2 and} the partial pressure of CH ₄ were determined by measuring the partial pressure of each gas component in the color cathode ray tube. As a result, the partial pressure of Ar was 2 × 10 ⁻⁶ Pa, and the partial pressure of N ₂ was 8 × 10 ⁻⁶ P
a, the partial pressures of CO and CO ₂ were 3 × 10 ⁻⁷ Pa, and the partial pressure of CH ₄ was 1.5 × 10 ⁻⁴ Pa.

When the electron emission characteristics of a color cathode ray tube using such a low gas emission getter device were examined, it was confirmed that electron emission defects due to ion bombardment were not observed, and the electron emission characteristics were excellent. Was. Further, the color cathode ray tube was subjected to a life test (6000 hours), and the characteristics thereof were examined. As a result, it was confirmed that the color cathode ray tubes had sufficiently good characteristics even after the life test.

Examples 2 to 5 and Comparative Example 1 In Example 1 described above, the conditions for degassing by high-frequency induction heating after filling the getter material into a stainless getter container were changed to the conditions shown in Table 1. , A getter device was manufactured in the same manner as in Example 1. Each of these getter devices was mounted in a color cathode ray tube, and a getter flash was performed in the same manner as in Example 1. Table 1 shows the partial pressure of Ar, the partial pressure of N _{2, the} partial pressures of CO and CO ₂ , and the partial pressure of CH ₄ in the gas released from the getter material at the time of getter flushing.

Further, as Comparative Example 1 with the present invention, a gas discharging step after filling a getter material into a stainless getter container is performed at 450 ° C. × 120 minutes using a normal vacuum heat treatment furnace. Except for the above, a getter device was manufactured in the same manner as in Example 1. This getter device was also mounted in a color cathode ray tube and a getter flash was performed in the same manner as in Example 1. The partial pressure of Ar in the gas released at this time, N
Table 1 also shows the ₂ partial pressures, the partial pressures of CO and CO ₂ , and the partial pressure of CH ₄ .

[0037]

[Table 1]

As is evident from Table 1, each of the getter devices according to Examples 2 to 5 has a significantly smaller amount of unnecessary gas components emitted during getter flush than the getter device of Comparative Example 1. And Example 2 shown in Table 1
When the electron emission characteristics of the color cathode ray tubes of Comparative Examples 1 to 5 and Comparative Example 1 were examined, electron emission defects due to ion bombardment were not observed in Examples 2 to 5, whereas in Comparative Example 1, partial electron emission was not observed. Poor release was observed. As described above, according to the present invention, the quality and reliability of the electron tube can be significantly improved.

[0039]

As described above, the getter device for an electron tube according to the present invention greatly reduces the amount of unnecessary gas components in the gas released from the getter material at the time of getter flash. Therefore, by using such a getter device, for example, a large electron tube or C
This makes it possible to essentially suppress ion impact on DT and the like, and greatly contributes to improvement in the quality and reliability of the electron tube.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a configuration of an embodiment of an electron tube getter device of the present invention.

FIG. 2 is a diagram illustrating a relationship between a heating temperature and a gas release amount when high-frequency induction heating is performed on a getter material filled in a getter container.

FIG. 3 is a diagram showing a relationship between a heating time and a flash Ba amount when high frequency induction heating is performed on a getter material filled in a getter container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Getter device for electron tubes 2 ... Getter container 3 ... Getter material for electron tubes

Claims (8)

[Claims] 1. A getter device for an electron tube comprising: a getter container made of metal; and a getter material filled in the getter container and containing a Ba—Al alloy powder and a Ni powder, wherein the getter material is a getter flash. A getter device for an electron tube, wherein a partial pressure of argon and nitrogen in a gas released at a time is 10 ⁻⁵ Pa or less. 2. The getter device for an electron tube according to claim 1, wherein the getter material has a partial pressure of a carbon-containing gas component in a gas released at the time of the getter flash of 10 ⁻³ Pa or less. Electron tube getter device. 3. A getter device for an electron tube, comprising: a getter container made of metal; and a getter material filled in the getter container and containing a Ba-Al alloy powder and a Ni powder. Inside at a temperature of 700 ~ 800 ℃ 30
A getter device for an electron tube, wherein high-frequency induction heating for less than a second is performed. 4. A step of filling a getter material containing a Ba-Al alloy powder and a Ni powder into a getter container;
Performing a high-frequency induction heating at a temperature of 700 to 800 ° C. in a vacuum for 30 seconds or less in a vacuum. 5. The method of manufacturing a getter device for an electron tube according to claim 4, wherein the high-frequency induction heating is performed on the getter material for 10 to 30 seconds. . 6. The method of manufacturing a getter device for an electron tube according to claim 4, wherein the high-frequency induction heating step comprises the steps of:
_{2. A} method of manufacturing a getter device for an electron tube, comprising a step of removing each gas component of CO, CO ₂ and CH ₄ . 7. An electron tube comprising the electron tube getter device according to claim 1. Description: 8. The electron tube according to claim 7, wherein the electron tube is a cathode ray tube for a large television or a cathode ray tube for a color display.