JPH06196096A - Aging method of cathode structure - Google Patents

Abstract

PURPOSE:To eliminate a bad effect such as the difficulty of regulation at the time of regulating the cut-off voltage of a cathode-ray tube or the damage to its image quality at viewing and listening to an image-receiving device (display) completed as a product. CONSTITUTION:A cathode body structure is provided with a cathode having a pellet in which a base body consisting of a porous high melting point metal is impregnated with an electron emitting material consisting of an alkali earth metal oxide; and first grid electrode and second grid electrode successively arranged in the electron emitting direction to the cathode. In the aging method of this cathode structure, to the cathode, a voltage of 10-100V is applied to the first grid electrode, and a voltage of 100-500V to the second grid electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for aging a cathode structure, and more particularly to a method for aging a cathode structure including a so-called impregnated cathode.

[0002]

2. Description of the Related Art This type of cathode assembly has a structure in which a base body made of a porous refractory metal is impregnated with an electron emitting substance made of an alkaline earth metal oxide.

A cathode ray tube (CRT) equipped with such an impregnated cathode uses an electron beam with a high current density of about 10 A / cm ^{2 at} a high anode voltage and displays an image with extremely high brightness for a long time. You can do it.

The cathode structure has a cathode temperature of about 1150 ° C. for the purpose of cleaning the electron emission surface or supplying the electron emission material to the electron emission surface during activation and aging in the manufacturing process. I am going to raise it.

[0005]

However, during activation and aging of such a cathode assembly, Ba or Ca, which is a partial element of the electron-emitting substance, is applied to the first grid electrode and the second grid electrode. It was discovered that the phenomenon of sticking occurs.

If Ba, Ca, or the like adheres to the first grid electrode and the second grid electrode in this manner, the adjustment becomes difficult at the time of adjusting the cutoff voltage of a cathode ray tube incorporating the cathode structure. Or, when viewing an image receiving device (display) completed as a product, there has been a problem that the image quality is deteriorated.

That is, when Ba, Ca or the like is attached to the first grid electrode and the second grid electrode, unnecessary grid electrode emission or stray emission is generated from the first grid electrode and the second grid electrode. This is because of that.

The present invention has been made under such circumstances, and an object of the present invention is to make the adjustment difficult at the time of adjusting the cutoff voltage of the cathode ray tube, or to make it as a product. An object of the present invention is to provide a method for aging a cathode structure that does not cause a problem such as deterioration of image quality when viewing a completed image receiving device (display).

[0009]

In order to achieve such an object, the present invention is basically to impregnate a substrate made of a porous refractory metal with an electron emitting substance made of an alkaline earth metal oxide. In a method for aging a cathode assembly, the cathode including the pellets, and a first grid electrode and a second grid electrode that are sequentially arranged in the electron emission direction with respect to the cathode. 10 to 100V for the electrode, 100 to 100 for the second grid electrode
It is characterized in that a voltage of 500 V is applied.

[0010]

In the aging method of the cathode structure constructed as described above, particularly, the first grid electrode is connected to the cathode by 10 to 10 times.
By applying a voltage of 100 to 500 V to the second grid electrode of 100 V, the first grid electrode and the second grid electrode
It was confirmed that the amount of Ba or Ca attached to each grid electrode was reduced.

Therefore, unnecessary grid electrode emission or stray emission does not occur from the first grid electrode and the second grid electrode, which makes adjustment difficult when adjusting the cutoff voltage of the cathode ray tube. Or, when viewing the image receiving device (display) completed as a product, it does not cause any adverse effect such as impairing the image quality.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a block diagram showing the outline of an image receiving device in which an embodiment of the cathode assembly to which the present invention is applied is incorporated.

In FIG. 1, there is a glass envelope 1, and a fluorescent screen 3 is formed on the inner wall of a face plate portion 2 of the glass envelope 1. The phosphor screen 3 is formed by alternately coating stripes of phosphors of three colors (R, G, B).

An electron gun assembly 30 is arranged in the neck portion 22 of the glass envelope 1 so as to face the fluorescent screen 3.

The electron gun assembly 30 is composed of red (G), green (G), and blue (B) electron guns.

One of the electron guns is a cathode (cathode) 6, a first grid electrode 9, a second grid electrode 10,
The electrodes 11, 12, and 13 forming the front lens, the converging electrode 13 forming the rear lens, and the shielding cup 15 are sequentially arranged with their central axes aligned. The same configuration is adopted in other electron guns, and the above-mentioned electrodes and the like are integrally formed with electrodes having the same function in other electron guns.

Here, the cathode (cathode) 6 is configured as a so-called impregnated type cathode having a pellet made by impregnating a substrate made of a porous refractory metal with an electron emitting substance made of an alkaline earth metal oxide. It has become a thing.

A voltage is applied to each of the electrodes and the cathode 6 which are integrally formed as described above via the stem pin 23, and an electron beam emitted from each cathode 6 is applied by applying the voltage. Is to be irradiated onto the phosphor screen 3 with a predetermined beam diameter.

A shadow mask 4 is disposed on the side of the phosphor screen 3 which faces the electron gun structure 30. The electron beams from the electron guns are focused on the surface of the shadow mask 4 and simultaneously overlap each other. Has become.

That is, each electron beam is adapted to be color-selected by the shadow mask 4, and only the component for exciting and emitting the phosphor of the color corresponding to each electron beam of the shadow mask 4. It reaches the phosphor screen 3 through the opening.

In order to scan the fluorescent screen 3 with such an electron beam, an external magnetic deflection yoke 16 is provided on a part of the outer surface of the glass envelope 1.

The electron gun assembly (cathode assembly) 30 in the image receiving apparatus thus configured has the first grid electrode with respect to the cathode (6, 7, 8) at the time of activation and aging during its manufacture. 9. A predetermined voltage is applied to each of the second grid electrode 10 and the second grid electrode 10.

Here, FIG. 1 shows the voltages applied to the first grid electrode 9 and the second grid electrode 10, respectively.
6 is a graph showing the relationship with the amount of Ba evaporated from the cathode and attached to each of the first grid electrode 9 and the second grid electrode 10.

As can be seen from this graph, the first
When the voltage applied to the grid electrode 9 is increased, the amount of Ba adhering to the first grid electrode 9 is decreased, and when the voltage applied to the second grid electrode 10 is increased, this It is found that the amount of Ba attached to one grid electrode 10 is reduced.

However, if the voltage is increased without limit, the first and second grid electrodes are heated to a high temperature by the electron beam irradiation and melted, or an electric field is applied to the cathode beyond the electron emission capability of the cathode. , Problems such as emission slump will occur.

From the above, the cathodes (6, 7,
For 8), it is optimal to apply a voltage of 10 to 100 V to the first grid electrode 9 and a voltage of 100 to 500 V to the second grid electrode 10.

Incidentally, FIG. 3 is a graph showing the relationship of the amount of Ba evaporated from the so-called impregnated type cathode pellets based on experiments when the present invention is not applied.

As is clear from this graph, the main component of the electron-emitting substance, Ba, is that the higher the operating temperature, the larger the amount of evaporation thereof, and that it decreases with the passage of time.

FIG. 4 shows the Ba evaporation amount obtained from the experimental results. In the figure, B up to 20,000 hours of product mounting
a If the evaporation amount is 100%, 30% of the evaporation will occur during the product process.

According to the aging method of the cathode structure according to the above-mentioned embodiment, in particular, 10 to 100 V is applied to the first grid electrode and 100 to 5 is applied to the second grid electrode with respect to the cathode.
It was confirmed that the amount of Ba or Ca attached to each of the first grid electrode and the second grid electrode was reduced by applying the voltage of 00V.

Therefore, unnecessary grid electrode emission or stray emission does not occur from the first grid electrode and the second grid electrode, which makes the adjustment difficult when adjusting the cutoff voltage of the cathode ray tube. Or, when viewing the image receiving device (display) completed as a product, it does not cause any adverse effect such as impairing the image quality.

[0032]

As is apparent from the above description,
According to the aging method of the cathode structure according to the present invention, the adjustment is made difficult at the time of adjusting the cutoff voltage of the cathode ray tube, or the image quality is impaired when viewing the image receiving device (display) completed as a product. It will not cause any adverse effects.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the voltage applied to the grid electrode and the amount of Ba deposited on the cathode assembly according to one embodiment of the present invention.

FIG. 2 is a configuration diagram showing an outline of an image receiving device in which an embodiment of a cathode assembly to which the present invention is applied is incorporated.

FIG. 3 is a graph showing the relationship of the amount of Ba deposited on a grid electrode when the present invention is not applied.

FIG. 4 is an explanatory diagram showing a relationship of a Ba adhesion amount in a mounting operation time when the present invention is not applied.

[Explanation of symbols]

6, 7, 8 ... Cathode, 9 ... First grid electrode, 10 ...
Second grid electrode.

Claims (1)

[Claims] 1. A cathode comprising a pellet in which a substrate made of a porous refractory metal is impregnated with an electron emitting substance made of an alkaline earth metal oxide, and a cathode arranged in the electron emitting direction with respect to the cathode. In a method for aging a cathode structure having a first grid electrode and a second grid electrode, the first grid electrode is 10 to 10 with respect to the cathode.
A method of aging a cathode structure, characterized in that a voltage of 0 V and a voltage of 100 to 500 V is applied to the second grid electrode.