JPH06139941A - Aging method of cathode ray tube - Google Patents

Abstract

(57) [Summary] [Object] To provide a method for aging a cathode ray tube capable of reliably preventing deterioration of a cathode image under a low exhaust temperature without using special equipment. [Structure] After the getter flash step, only the heater energization of the cathode 8 of the electron gun is performed for 50 minutes until the vacuum degree in the cathode ray tube becomes 9 × 10 ⁻⁶ Torr or less, and then the heater energization and the current activation are performed for 20 minutes. Do for a minute.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aging method in a cathode ray tube manufacturing process.

[0002]

2. Description of the Related Art In recent years, in order to improve the production efficiency of cathode ray tubes,
The vacuum exhaust treatment temperature is being lowered. That is, the maximum exhaust temperature that was conventionally 320 ° C to 360 ° C is 2
By setting the temperature to 50 ° C to 280 ° C, the index can be shortened by 25% to 30% and the energy cost can be reduced. On the other hand, in order to simplify the exhaust furnace process and stabilize the cathode characteristics, do not perform gun firing and cathode decomposition activity in the exhaust furnace, and perform gun firing and decomposition activity after the vacuum sealing and getter flash steps. Has also been done. In the manufacturing process of such a cathode ray tube, aging is performed by energizing the heater of the cathode of the electron gun and activating the current.

[0003]

However, the cathode ray tube manufactured under such conditions has a large amount of residual gas for a few hours immediately after the getter is blown in the getter flash step, so that the cathode is not used in the subsequent aging step. There is a problem that the characteristics, particularly the cathode image (beam spot image when the fluorescent surface is irradiated with the beam) are deteriorated. That is, when the exhaust temperature is low, the amount of water remaining in the pipe after exhaust increases, so that the amount of methane gas (CH ₄ ) generated by the reaction with the barium getter increases. Also, during gun firing and decomposition activity, a large amount of carbon dioxide, hydrogen, and water are released from the electron gun and cathode,
Methane gas is easily generated by the reaction with the getter film. These reactions proceed according to the following well-known reactions to produce methane.

First-order reaction: 3Ba + 2CO → 2BaO + BaC ₂ 5Ba + 2CO ₂ → 4BaO + BaC ₂ Ba + H ₂ O → BaO + 2 (H) Second-order reaction: BaC ₂ + H ₂ O → BaO + 2 (CH) 2 (CH) +6 (H) → 2CH ₄

The methane gas thus generated and remaining in the tube is decomposed mainly during thermal activation due to heater energization in the aging process, and as shown in FIG. 6, during cathode current activation, that is, along with heater energization. A predetermined voltage (for example, V _C = 0V, V ₁ = 10V, V ₂ =) is applied to the cathode 10 and the first and second grids G ₁ and G _2.
When 200 V) is applied, ion bombardment of carbon ions (C ⁺ ) occurs on the surface of the cathode 10, causing deterioration of emission.

In order to prevent this ion bombardment, the following method has been conventionally performed. 1) Ion collect method (see FIG. 7) A voltage for current activation is applied to the first and second grids G ₁ and G ₂ , and a few tens of minus to several third grids are applied.
A method of applying a voltage of several hundreds of V and pulling the generated positive ions to the third grid G ₃ side. 2) Raster aging Before current activation in the aging process, a high voltage of 10 kV to 20 kV, which is close to the normal operating conditions of a cathode ray tube, is applied, and methane gas is decomposed by a high-energy electron beam for a short time (several tens of seconds) to a getter. How to absorb.

However, in the above method 1), the first
Carbon ions generated and present in the vicinity of the grid G ₁ cannot be adsorbed on the third grid G ₃ , so that ion bombardment cannot be completely prevented. Therefore, when the amount of methane gas remaining in the tube is small, the damage to the cathode surface is small, but the emission deterioration occurs as the amount of methane gas increases. On the other hand, the method of 2) above is very effective because methane gas can be removed in a short time, but the electron beam impinges on the fluorescent surface, so that surface burning failure occurs. Therefore, the aging pallet (hanger), which has conventionally been composed only of a mount for a socket and a cathode ray tube, must be equipped with a deflection yoke for preventing surface burning and also equipped with equipment for supplying a deflection power source and a high voltage power source. In addition, there are many problems in terms of equipment, which requires a considerably large amount of equipment investment, and is also troublesome in maintenance.

The present invention has been made in view of the above points of the conventional example, and an object thereof is to provide a cathode ray which can surely prevent deterioration of the cathode image under a low exhaust temperature without using special equipment. It is to provide a method of aging a tube.

[0009]

According to the present invention, for example, as shown in FIG. 1 or 4, the degree of vacuum in the cathode ray tube is 9 × 1.
The heater 8 is only energized to the cathode 8 of the electron gun until it becomes 0 ^-6 Torr or less, and then current activation is performed.

[0010]

In the present invention having such a structure, the residual gas in the tube is decomposed by energizing the heater, and the current activation is performed after the vacuum degree in the tube reaches a sufficiently high value of 9 × 10 ⁻⁶ Torr or less. From the cathode during current activation
The number of carbon ions hitting the surface is greatly reduced.

[0011]

Embodiments of the aging method for a cathode ray tube according to the present invention will be described below with reference to the drawings.

FIG. 2 shows an example of a cathode ray tube to which the present invention is applied. In the figure, a tube body 3 is composed of a panel 1 and a funnel 2 each made of glass.
A fluorescent screen 1 a is formed on the inner surface of the panel 1. Further, a plurality of panel pins 4 are provided on the skirt portion 1b of the panel 1, and a color selecting mechanism 6 is supported on these panel pins 4 by a spring 5. The panel 1 and the funnel 2 are fixed to each other by a frit sealing process. A cylindrical neck portion 2a is fixed to the funnel 2, and an electron gun 7 having a plurality of grids is sealed in the neck portion 2a. The cathode 8 of the electron gun 7 is provided with a heater 9 described later.

Next, the aging method of this embodiment will be described. Generally, the aging process is performed at the final stage of the manufacturing process of the cathode ray tube, and in the case of this embodiment as well, various known processes, that is, the assembly of the funnel, the panel and the electron gun, the frit sealing, the electron gun sealing, and the exhaust are performed. , Getter flash, reinforcing treatment, coating of exterior carbon, and knocking.

The aging process, as shown in FIG.
It includes a step of energizing the heater 9 provided in the cathode 8 (heater energization) and a step of applying a predetermined voltage to the first grid G ₁ and the second grid G ₂ (current activation). In the current activation of this embodiment, for example, the cathode 8 is grounded (V _C = 0V) as in the prior art, while the predetermined voltage (V ₁ = + 10) is applied to the first and second grids G ₁ and G _2.
V, V ₂ = + 200 V) is applied.

When the heater is energized, the gas remaining in the tube body 3 is decomposed and absorbed by the getter film formed on the inner surface of the tube body 3. In this case, it was found that the methane gas was also decomposed when the heater energization was increased from the conventional 6.3 V to about 10 V. On the other hand, due to current activation, the cathode 8
Electrons e ⁻ are emitted from the cathode and the cathode surface is activated.

FIG. 1B shows a schedule of the aging method of this embodiment. As shown in the figure, in the case of the present embodiment, the current activation is started 50 minutes after the heater energization is started, and the heater energization and the current activation are activated 20 minutes later, that is, 70 minutes after the heater energization is started. finish.
Here, the reason why the current activation is started 50 minutes after the start of energization of the heater is as follows.

That is, the present inventors have conducted many tests on the relationship between the degree of vacuum in the tube 3 and the cathode characteristics at the start of current activation, and as a result, as shown in FIG. It was found that when the degree of vacuum at 9 is less than 9 × 10 ⁻⁶ Torr, the cathode 8 is not deteriorated by ion bombardment. In this case, regarding the good or bad of the cathode characteristic, the slumping characteristic (the characteristic showing the current value after 10 seconds with respect to the initial current when the electron beam is extracted from the cathode by applying a constant voltage) is 92% or less, or Cathode quality (one obtained by evaluating the current obtained from the cathode after aging with a preset reference current as 1) having 1.0 or less is regarded as a defect,
Others were good.

On the other hand, as shown in FIG. 4, the degree of vacuum in the tube body 3 of the cathode ray tube which has undergone the evacuation and getter flash steps increases with the passage of time due to decomposition of residual gas by energizing the heater (1 hour). Is about 1 digit or more), but in that case, the lower the exhaust temperature, the higher the degree of vacuum. As can be seen from the figure, even when the exhaust temperature is as low as 270 ° C., a vacuum degree of 9 × 10 ⁻⁶ Torr or less can be obtained if the heater is energized for at least 50 minutes. Therefore, 50 after starting energizing the heater
If the current activation is started at the time when a minute has passed, the deterioration of the cathode 8 due to ion bombardment can be prevented. Further, at the time of starting the current activation, the cathode 8 is turned on by energizing the heater.
Has recovered to a certain degree, so the time for current activation is 2
It turned out that about 0 minutes is sufficient.

Comparative Example As a comparative example, the same cathode ray tube as in the example was used, and as shown in FIG. 5, aging was performed according to a schedule in which current activation was started about 10 minutes after the heater was energized. This is a conventional aging method. In this case, it is estimated from FIG. 4 that the degree of vacuum becomes 9 × 10 ⁻⁶ Torr or less at the start of current activation when the exhaust temperature is 340 ° C. or higher. In fact, in this comparative example, the exhaust temperature can be lowered to around 300 ° C. However, when the cathode 8 of the electron gun of the cathode ray tube which was exhausted at the temperature of 300 ° C. was examined, the current activation was started. After 20 minutes, it was revealed that ion bombardment occurred in the cathode 8 and the emission was deteriorated.

During the period from 30 minutes after the start of energization of the heater to 50 minutes at the end of the current activation, the cathode 8 has been recovered to some extent by the energization of the heater, so that 3
Exhaust up to 00 ° C was possible.

As is clear from the above results, according to this embodiment, it is sufficient to shift the time point at which the current activation starts from the heater energization start to the later time without changing the total aging time. Excellent cathode characteristics were obtained, and low temperature exhaust at 300 ° C or lower was possible. Further, in the conventional method, when the exhaust temperature was 340 ° C. or lower, the cathode 8 was damaged during the aging, but according to the present embodiment, the damage of the cathode 8 can be completely avoided, and the initial characteristics It can be expected that both life characteristics will be improved.

The present invention is not limited to the above embodiments, but can be implemented in various modes. That is,
Within the scope of the present invention, various values such as the voltage applied to the heater and the grid, the start timing of the current activation, and the continuous time thereof can be set. Moreover, the present invention is applicable to all cathode ray tubes.

[0023]

As described above, according to the present invention, the degree of vacuum in the tube is raised to 9 × 10 ⁻⁶ Torr or less by energizing the heater of the cathode of the electron gun, and then the current activation is performed. It is possible to surely prevent the deterioration of the cathode image without using special equipment. Further, according to the present invention, the exhaust treatment temperature can be lowered without making a major facility modification, and as a result, the production efficiency of the cathode ray tube can be improved.

[Brief description of drawings]

1A is an explanatory view showing an embodiment of an aging method for a cathode ray tube according to the present invention. FIG. B is a graph showing an aging schedule of the example.

FIG. 2 is a sectional view showing an example of a cathode ray tube to which the present invention is applied.

FIG. 3 is a graph showing cathode characteristics after aging.

FIG. 4 is a graph showing the relationship between the heater energization time and the degree of vacuum in the tube.

FIG. 5 is a graph showing an aging schedule of a comparative example.

FIG. 6 is an explanatory diagram showing a conventional aging method.

FIG. 7 is an explanatory diagram showing an ion collect method.

[Explanation of symbols]

7 Electron gun 8 Cathode 9 Heater G ₁ 1st grid G ₂ 2nd grid

Claims (1)

[Claims] 1. The degree of vacuum in the cathode ray tube is 9 × 10 ⁻⁶ T.
A method for aging a cathode ray tube, which comprises only energizing a heater of a cathode of an electron gun until it becomes equal to or lower than orr, and then performing current activation.