JPH06131978A - Manufacture of cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent the damage to a cathode and provide a good cathode characteristic without using a special facility and without increasing the exhaust temperature by dispensing with current activation during the aging process. CONSTITUTION:The heater of a cathode 8 is heated only by excitation during the aging process of the cathode 8, and no current activation is performed. During exhaust or electron gun sealing/getter flash processes after the disassembly/activation of the cathode 8, the cleaning of the surface of the cathode 8 is not required if the surface of the cathode 8 is not re-polluted by the residual gas in a tube. No current activation is required when an electron beam is squeezed and fed to a fluorescent screen from the through hole of an electron gun electrode like in a cathode-ray tube. Aging is performed only by heater excitation with no current activation, and the damage to the cathode 8 is prevented and a good cathode characteristic can be obtained without increasing the exhaust temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cathode ray tube, and more particularly to a method for aging a cathode ray tube using a flittable getter.

[0002]

2. Description of the Related Art In recent years, fritable getters have been used especially in high definition tubes in order to improve the reliability and accuracy of cathode ray tubes. Such a fritable getter was developed as an alternative to the antenna getter attached to the conventional electron gun, and is used after the frit sealing process after pre-installing it on a funnel or a color selection mechanism. Since it is expected to improve the electron gun off-axis, it is widely used in cathode ray tubes.

[0003]

However, when the cathode ray tube using the fritable getter is subjected to exhaust treatment at a temperature of about 320 ° C. as in the case of using a normal antenna getter, the characteristics of the cathode are deteriorated. The problem arises. That is, in the cathode ray tube using the fritable getter, carbon dioxide gas or water is adsorbed to the fritable getter during the frit sealing process,
When the exhaust temperature is around 320 ° C., these carbon dioxide gas and the like remain in the getter, and a large amount of hydrocarbons are generated in the subsequent getter flash process. The generated gas cannot be easily decomposed only by energizing the heater in the subsequent aging process, and the residual gas damages the cathode during the current activation in the aging process. The heater is energized by energizing only the cathode heater without applying a voltage to the grid, for example, BaO → Ba +
This is because the reaction of 1 / 2O ₂ is caused, and the current activation mainly applies an electric potential to the first grid and the second grid to cause the beam from the cathode to collide with the first and second grids to cause degassing. It is a thing. In order to solve the above-mentioned problems, the exhaust temperature is raised to 340 ° C. or higher, or so-called raster aging before aging (high voltage 10 close to normal operating conditions before current activation of aging).
A method of applying KV to about 20 KV, decomposing methane gas with a high-energy electron beam in a short time (several tens of seconds) and absorbing it by a getter. However, it is difficult to adopt these methods because increasing the exhaust temperature lowers productivity and requires special equipment for raster aging.

The present invention has been made in view of the above points of the conventional example, and an object thereof is to prevent damage to the cathode without using special equipment or raising the exhaust temperature. It is an object of the present invention to provide a method of manufacturing a cathode ray tube capable of obtaining good cathode characteristics.

[0005]

According to the present invention, for example, as shown in FIG. 1, a frit sealing step (step) for fixing a panel and a funnel constituting a tube body of a cathode ray tube in a predetermined position, and fixing them. The step (step) of sealing the electron gun inside the neck of the funnel, the step of exhausting the tube to create a vacuum, and the heating of the fritable getter placed inside the tube from outside the tube. A getter flash step (step) of vapor-depositing on the inner surface of the tube, and an aging step (step) of energizing only the heater of the cathode of the electron gun.

[0006]

In the present invention having such a structure, current activation is not performed during the aging step, so that damage to the cathode by the gas remaining in the tube can be prevented. Therefore, according to the present invention, it is not necessary to raise the exhaust gas temperature, and it is not necessary to perform raster aging before aging.

[0007]

Embodiments of the method of manufacturing a cathode ray tube according to the present invention will be described below with reference to the drawings. It should be noted that in the following description, description of well-known portions not directly related to the present invention will be omitted.

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 described later.

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. A heater (not shown) is arranged on the cathode 8 of the electron gun 7.

FIG. 1 shows an essential part of this embodiment.
First, the funnel 2, the panel 1 and the electron gun 7 are assembled by a known method (step). In this case, a fritable getter is attached to the color selection mechanism 6 incorporated in the funnel 2 or the panel 1. The fritable getter is made of Ni and Ba as in the case of the conventional getter material.
It is composed of Al _4, but has a larger Ni grain size.

Next, a frit sealing process is performed (step). That is, the funnel 2 coated with the frit paste and the panel 1 are aligned at a predetermined position, and the frit is melted and crystallized to fix the joint surface.

Further, the electron gun 7 is arranged in the neck portion 2a, and the stem portion of the electron gun 7 and the neck portion 2a are welded to seal the electron gun 7 (step).

Then, using a vacuum pump, for example, 320
The inside of the tube body 3 is evacuated in an exhaust furnace at a temperature of ℃ to make the inside of the tube body 3 a vacuum. Further, the chip-off tube is sealed (step).

After that, the fritable getter is heated from the outside of the funnel 2 by high frequency to vapor-deposit the Ba film on the inner surface of the tube body 3 to make the inside of the tube body 3 higher vacuum (step).

Further, a reinforcing treatment is carried out to prevent damage (implosion) of the glass (step), and a carbon coating is formed on the outer surface of the funnel 2 to form a capacitor for a high voltage smoothing circuit (step).

After that, a high voltage is applied to the electron gun 7, and a knocking step is performed so that discharge does not occur near the electron gun 7 during normal operation (step).

Finally, the aging process of the cathode 8 is performed. In this case, in the present embodiment, only heating by energizing the heater of the cathode 8 is performed, and current activation is not performed. This is for the following reason. That is, the original purpose of current activation is to perform degassing by colliding an electron beam with the parts of the electron gun 7 and to clean the surface of the cathode 8 by ion bombardment of gas remaining in the tube, especially hydrogen gas. The aim is to achieve uniformization and uniform barium concentration.
Therefore, we examined how the characteristics of the cathode ray tube change depending on the presence or absence of such current activation. The result is shown in FIG. In this case, the exhaust temperature was 320 ° C.

The slumping characteristic of FIG. 3A is a characteristic showing the current value after 10 seconds with respect to the initial current when the electron beam (current) is extracted from the cathode by applying a constant voltage. The cathode quality in FIG. 3B is an evaluation of the current obtained from the cathode after aging with the preset reference current being 1.

As can be seen from FIGS. 3A and 3B, the cathode characteristics are not deteriorated without current activation, that is, without degassing the parts of the electron gun 7, and there is a difference in the life characteristics and the standing characteristics of the cathode ray tube. Did not happen. In addition, these characteristics were not affected even if the parts of the electron gun 7 were not degassed by high frequency induction heating in an exhaust furnace or the like. It is considered that the cause of the difference in characteristics in the past examples is caused by causing an electron beam to flow through the parts of the electron gun 7, or when the cathode decomposition activation condition is inappropriate.

Further, after the decomposition activity of the cathode, it is not necessary to clean the surface of the cathode 8 in the process of exhausting, sealing with an electron gun, getter flash, etc., unless there is recontamination of the surface of the cathode 8 by the residual gas in the tube. I also found out.

From the above results, the main role of current activation is
It is necessary when the electron beam is used by directly flowing it to the metal electrode, and current activity is not necessary when the electron beam is squeezed and passed from the through hole of the electron gun electrode to the fluorescent screen like a cathode ray tube. found.

Therefore, according to the present embodiment in which the aging is performed only by energizing the heater without activating the current, damage to the cathode 8 can be prevented without requiring special equipment and raising the exhaust temperature. As a result, good cathode characteristics can be obtained.

Although the present invention uses a fritable getter, the present invention can be applied even when a conventional getter is used when exhausting at a low temperature.

The present invention can be applied to any cathode ray tube using an aperture grill or a shadow mask as a color selection mechanism, and can be applied to various other cathode ray tubes.

[0025]

As described above, according to the present invention, since only the heater energization of the cathode of the electron gun is performed in the aging step, the cathode is used without using special equipment and without raising the exhaust temperature. It is possible to prevent damage to the cathode and obtain good cathode characteristics.

[Brief description of drawings]

FIG. 1 is a flowchart showing a main part of an embodiment of a method for manufacturing a cathode ray tube according to the present invention.

FIG. 2 is a partial cross-sectional view showing a schematic configuration of a cathode ray tube to which the present invention is applied.

FIG. 3 is a graph showing cathode characteristics of this example and a conventional example.

[Explanation of symbols]

 1 Panel 2 Funnel 2a Neck 3 Tube 7 Electron Gun 8 Cathode

Claims (1)

[Claims] 1. A frit sealing step of fixing a panel forming a tube body of a cathode ray tube and a funnel in a predetermined position, and fixing the electron gun in a neck portion of the funnel; An evacuation process for creating a vacuum, a getter flash process for heating the flittable getter arranged in the tube from the outside of the tube to deposit it on the inner surface of the tube, and an aging step for only energizing the heater of the cathode of the electron gun. And a method for manufacturing a cathode ray tube, comprising: