JP2002008538A - Manufacturing method of cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cathode ray tube capable of improving an electron emission property by the quantitative control of inner gas atmosphere during aging process. SOLUTION: In the manufacturing method of the cathode ray tube, by releasing at least one kind of specific gas of either Ar gas, N2 gas, or H2 gas from a part in a bulb, before aging process 22 in the cathode ray tube, the pressure of the specific gas in the cathode ray tube at the aging process 22 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube used for a computer display, a television receiver, and the like, and more particularly to a manufacturing method for improving the electron emission characteristics of the cathode.

[0002]

2. Description of the Related Art Generally, in order for a cathode ray tube to have a long life (can be used for a long period of time), it is important that the cathode emits a large amount of electrons and that the cathode is hardly deteriorated. In order to guarantee the electron emission characteristics of such a cathode over a long period of time, it is recognized that the gas atmosphere in the tube during the cathode ray tube manufacturing process is important in addition to the characteristics of the cathode itself obtained by the material and forming conditions. Have been.

[0003]

However, conventionally,
The optimum gas atmosphere in the tube for obtaining good electron emission characteristics and the means for obtaining the optimum gas atmosphere have not been specifically known.

In the aging step performed for activating the cathode after the exhausting step of the cathode ray tube, CH ₄ and oxidizing gas are present in the cathode ray tube, and these gases contaminate the emitter surface of the cathode, so that emission is caused. Tends to decrease. When the emission is reduced as described above, there is a problem that excellent electron emission characteristics cannot be obtained.

The present invention has been made in view of the above problems, and provides a method of manufacturing a cathode ray tube capable of improving electron emission characteristics by quantitatively controlling a gas atmosphere in a tube during an aging process. Is what you do.

[0006]

In order to solve the above problems, in the method of manufacturing a cathode ray tube according to the present invention, at least one of Ar gas, N ₂ gas and H ₂ gas is placed in the cathode ray tube before the aging step. The gas pressure of the specific gas in the cathode ray tube in the aging step is controlled by discharging the specific gas from the tube components.

[0007] By doing so, it is possible to realize a cathode ray tube having a small emission reduction and excellent electron emission characteristics.

In the method for manufacturing a cathode ray tube according to the present invention,
The specific gas is Ar gas, and the Ar gas pressure in the cathode ray tube in the aging step is 2.0 × 10 ⁻⁵ to 2.0 × 10 ⁻⁵ .
2.0 a × 10 ^-2 Pa, or, the specific gas is N ₂ gas, the aging N ₂ gas pressure in the cathode ray tube in step 5.0 × 10 ^-5 ~2.0 × 10 ^{- Two}
It is preferably Pa.

In this manner, these specific gases are ionized during the aging step, and collide with the low voltage cathode emitter, thereby cleaning the emitter surface.

Further, according to the method for manufacturing a cathode ray tube of the present invention,
The specific gas is H ₂ gas, and the H ₂ gas pressure in the cathode ray tube in the aging step is 2.0 × 10 ⁻⁵ to
It is preferably 2.0 × 10 ⁻² Pa.

By doing so, the electron emitting substance is reduced and activated.

Further, in the method of manufacturing a cathode ray tube according to the present invention, it is preferable that the tube component is a getter device, and the specific gas is released by a getter flash.

With this configuration, it is possible to easily realize a configuration for releasing the specific gas in the pipe.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

A cathode ray tube shown as an example in FIG. 2 has a panel 2 having a fluorescent screen 1 formed on the inner surface and an electron gun 4 on a neck 3.
An envelope is formed from a funnel 5 that houses therein a plurality of electrodes (although it is shown in a simplified diagram here, a plurality of electrodes are actually arranged). A shadow mask 6 is supported by the frame 7 so as to face the phosphor screen 1.
Is hooked on the inner wall of the panel 2 by a spring 8 and a panel pin 9. Further, as other main parts, a magnetic shield 10 for shielding a magnetic field, a contact spring 11 for electrical conduction between the shadow mask 6 and the conductive film on the inner wall of the funnel 5, and a coating of a getter material are formed in the tube. There is a getter device 12 or the like for performing the operation.

In such a cathode ray tube, electrons emitted from the cathode portion 4a of the electron gun 4 are focused by the electric field lens effect of the electron gun 4 to form an electron beam 13, and the electron beam 13
An image signal is placed on the panel 2 and projected onto a predetermined position on the phosphor screen 1 while being deflected by the action of the deflection yoke 14, thereby displaying an image on the panel 2.

Here, the cathode section is provided with three cathodes corresponding to each of the three electron beams. As shown in FIG. 3 as an example, these cathodes are formed by adhering an emitter 16 made of an electron-emitting substance such as an alkaline earth metal on a substrate 15.
The structure is such that electrons are emitted from the emitter 16 by being heated by the heater 18 in the cylindrical body 17 below.

The present invention has a feature in the manufacturing method after the electron gun is sealed in the funnel for the purpose of improving the electron emission characteristics from the emitter. Hereinafter, the manufacturing method will be described in detail.

FIG. 1 partially shows an example of a flow chart of a cathode ray tube manufacturing process. First, after all other in-tube components except the electron gun are assembled, in a sealing step 19, the electron gun is sealed in the neck of the funnel. Then, the exhaust in step 20, fitted with a vacuum exhaust system to the neck portion rearwardly, to release the adsorbed gas to the funnel inner wall and the like causes discharge the air in the tube, the tube high vacuum (1 × 10 ^-2 ~1 × 10 ^-3P
a)) and close the capillary. Thereafter, in a getter flash step 21, a getter material containing Ba is scattered from the getter device into the tube to adsorb the gas remaining in the tube, and a getter film is formed in the tube. Thereafter, the cathode is activated in an aging step 22, and the heater insulation characteristics are stabilized in a raster aging step 23.

Among the above processes, in the embodiment of the present invention, at a stage before the aging process, a specific gas is discharged from the inner tube of the cathode ray tube to control the gas pressure in the aging process. .

For example, Ar gas is previously contained in the getter material to be scattered in the getter flash step which is a step before the aging step, so that the Ar gas is released from the getter device before the aging step. A in advance for getter material
As a method of including the r gas, for example, a getter device may be manufactured in a desired Ar gas atmosphere and used. Here, in the aging step after the getter flash step, the Ar gas pressure is 2.0 × 10 ⁻⁵ to 2.0 × 10 ^−5.
The Ar gas atmosphere at the time of manufacturing the getter device is set to ⁻² Pa.

Alternatively, in the above manufacturing process, the getter material scattered in the getter flash step may contain N ₂ gas in advance. By doing this,
Before the aging step, N ₂ gas is released from the getter device. As a method of including N ₂ gas in the getter material in advance,
For example, a getter device may be manufactured by mixing iron nitride into a getter material and used. In this case, the N ₂ gas pressure is 5.0 × 10 ⁻⁵ in the aging step immediately after.
The amount of iron nitride is adjusted so as to be 2.0 × 10 ⁻² Pa.

As described above, by using a getter material containing Ar gas or N ₂ gas in advance in the getter flash step before the aging step, the Ar gas or N ₂ gas in the aging step can be controlled. Thereby, during the aging step or the raster aging step, the gas molecules are positively ionized by electrons emitted from the cathode in the tube, and a phenomenon called ion bombardment in which the ionized gas molecules collide with the low voltage side appears. . Due to this ion bombardment, ionized gas molecules collide with the emitter surface of the cathode on the low voltage side, and as a result, the emitter surface is cleaned. This cleans the cathode surface which is liable to be contaminated with CH ₄ and oxidizing gas during the aging step, so that activation is promoted and a decrease in emission immediately after aging is suppressed.

Further, in the getter flash step in the manufacturing process of FIG.
_Two gases may be released. For example, this can be realized by attaching a hydrogen storage alloy such as titanium to the getter device. By doing so, the temperature is increased in the getter flash step, so that the H ₂ gas is released from the hydrogen storage alloy. In this case, the amount of the hydrogen storage alloy or the like is adjusted so that the H ₂ gas pressure becomes 2.0 × 10 ^{−5 to} 2.0 × 10 ⁻² Pa in the subsequent aging step.

By releasing H ₂ gas in the getter flash step, the following chemical reaction occurs during aging.

H ₂ + BaO → H ₂ O + Ba By this reaction, in addition to free Ba from the electron-emitting substance due to normal thermocurrent activation, Ba generated by reduction of the electron-emitting substance is present. There is an effect of activating the radiating material layer, and a decrease in emission can be suppressed as compared with the related art.

As described above, these Ar atoms released into the tube before the aging step and acting in the aging step are used.
The gas, N ₂ gas, and H ₂ gas have a residue or a surplus remaining in the pipe even after the aging step, and these unnecessary and surplus portions after the aging must be eliminated. Here, the N ₂ gas and the H ₂ gas are adsorbed on the getter film as active gases during the life, so that there is no problem. On the other hand, the inert gas of Ar is ionized and injected into the low-pressure side and the high-pressure side, so that it decreases with time, but its degree is not so large, and becomes a high value as a residue. In order to minimize the inert gas of Ar, in the manufacturing process of FIG. 1, a process called an ion aging process for increasing the degree of vacuum in the tube by ionizing Ar and adsorbing it on a specific electrode is called a raster aging process. It is desirable to incorporate it later.

In this embodiment, as a method of releasing a specific gas before the aging step, an Ar gas or N ₂ gas is applied to the getter material in order to release the gas from the getter device in the getter flash step before the aging step. An example has been shown in which a getter device is provided with a hydrogen storage alloy in order to contain gas in advance or to release H ₂ gas. By doing so, it is possible to easily release gas by using the high temperature state at the time of getter flash as it is,
This can be achieved simply by providing the getter device with simple gas releasing means. However, the method is not limited to this, and as another method, a high-temperature step for releasing a gas before the aging step may be separately provided in addition to the getter flash step, or as a pipe part for releasing a gas. A special part other than the getter device may be newly provided in the pipe.

Next, the effect of the present invention will be described with reference to experimental results.

FIG. 4 shows the change in the initial emission rate with respect to the change in the gas pressure for the cathode manufactured by controlling the gas pressure in the aging step. Curve 24
Represents the Ar gas pressure, curve 25 represents the N ₂ gas pressure, and curve 26 represents the emission at the start of operation of the cathode manufactured at each gas pressure of 1 when the H ₂ gas pressure was varied.
It shows the emission rate after 5 minutes when 00% is set.

If the Ar gas pressure or the N ₂ gas pressure is too high, the emission is greatly reduced due to the damage of the emitter by the gas before the bombarding cleaning action appears. On the other hand, if the H ₂ gas pressure is too high, the pressure of H ₂ O generated in the reduction reaction will be too high, contaminating the cathode surface and reducing the emission. If the Ar gas pressure, N ₂ gas pressure, or H ₂ gas pressure is too low, the effect of preventing contamination of the emitter surface by CH ₄ or oxidizing gas is not sufficiently exhibited. This also causes the emission to decrease.

In the aging step, A in the cathode ray tube is
r gas pressure is 2.0 × 10 ^{−5 to} 2.0 × 10 ⁻² Pa, or N ₂ gas pressure is 5.0 × 10 ^{−5 to} 2.0 × 10 ⁻² P
a or the H ₂ gas pressure is 2.0 × 10 ^{−5 to} 2.0 × 1
It is desirable to set the pressure to 0 ^-2 Pa. By doing so, it is possible to realize a cathode ray tube which has little emission reduction and excellent electron emission characteristics.

The three types of gases are Ar gas,
By releasing any one of N ₂ gas and H ₂ gas into the pipe before the aging step, an effect of suppressing a decrease in emission is exerted. However, either Ar gas or N ₂ gas which causes an ion bombardment phenomenon, and Ba H ₂ with reducing action
A higher effect can be obtained by releasing the two types of gas together with the gas into the tube before the aging step.

FIG. 5 shows the results of an accelerated life test of a cathode ray tube. The curve 27 in the figure shows the Ar gas pressure, the curve 28 shows the N ₂ gas pressure, the curve 29 shows the H ₂ gas pressure,
In the aging step, the emission rate at the time of starting the life test of the cathode ray tube manufactured at 1.0 × 10 ⁻³ Pa is set to 100%, and the emission rate with time is shown. This shows the emission rate over time when the emission at the start of the life test is 100% for a conventional cathode ray tube that does not emit any special gas. The conventional cathode ray tube has insufficient activation in the early stage after the start of the life test, activates after about 100 hours, and a peak of emission appears, and thereafter, the emission rate sharply decreases. On the other hand, a cathode ray tube in which a specific gas is discharged into the tube before aging and the gas pressure in the aging process is controlled, the emission gradually decreases from the initial stage, so that the emission decrease after a long time has passed is small, It becomes a cathode ray tube with a long life.

[0035]

As described above, by controlling the gas pressure in the aging process by releasing a specific gas into the tube before the aging process as in the present invention, the gas can be obtained by activation in the conventional aging process. The electron emission characteristics can be further improved, and a cathode ray tube having good electron emission characteristics for a long period can be manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram showing a partial example of a process flow in a method of manufacturing a cathode ray tube according to the present invention.

FIG. 2 is a partial sectional view showing an example of a cathode ray tube.

FIG. 3 is a partial cross-sectional view showing an example of a cathode.

FIG. 4 is a diagram showing a relationship between a gas pressure and an initial emission rate in an aging step.

FIG. 5 is a diagram comparing the emission rates of a cathode ray tube obtained by the manufacturing method of the present invention and a conventional cathode ray tube in a life test.

[Explanation of symbols]

 22 Aging process

Claims (5)

[Claims] In the method of manufacturing a cathode ray tube, at least one specific gas of Ar gas, N ₂ gas, and H ₂ gas is released from components inside the tube in the cathode ray tube before the aging step, so that the aging step is performed. A method for manufacturing a cathode ray tube, comprising controlling a gas pressure of the specific gas in the cathode ray tube. 2. The cathode ray according to claim 1, wherein the specific gas is Ar gas, and an Ar gas pressure in the cathode ray tube in the aging step is 2.0 × 10 ^{−5 to} 2.0 × 10 ⁻² Pa. Pipe manufacturing method. 3. The method according to claim 1, wherein the specific gas is N ₂ gas, and the N ₂ gas pressure in the cathode ray tube in the aging step is 5.0 × 10 ^{−5 to} 2.0 × 10 ⁻² Pa. Method for manufacturing a cathode ray tube. 4. The method according to claim 1, wherein the specific gas is H ₂ gas, and a pressure of H ₂ gas in the cathode ray tube in the aging step is 2.0 × 10 ^{−5 to} 2.0 × 10 ⁻² Pa. Method for manufacturing a cathode ray tube. 5. The pipe part is a getter device, and the specific gas is released by a getter flash.
5. The method for manufacturing a cathode ray tube according to any one of items 1 to 4.