JP3175199B2 - Oxide cathode activation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an oxide (oxide).
The present invention relates to a cathode activating method, and more particularly to an oxide cathode activating method for a picture tube, which prevents a cathode material from adhering to grid electrodes G1 and G2.

[0002]

2. Description of the Related Art In the manufacture of a picture tube (CRT), FIG.
As shown in FIG. 2, an electron gun 5 having an oxide (oxide) cathode is inserted into a neck tube 4 having a structure in which a panel 1 coated with a phosphor screen and a funnel 3 are joined by a frit 2 and then the end of the neck tube with a gas burner. After melting and sealing the part
Attach the tip tube 6 at the rear end of the electron gun to the exhaust dolly,
Using a vacuum rotary pump (not shown), the picture tube 20
The pressure of the primary exhaust is set to 10 ^-3 to 10 ^-4 Torr, and the pressure in the picture tube is set to 10 ^-4 to 10 by operating a diffusion pump.
Reduce to ^-5 Torr and apply vacuum.

FIG. 2 is an enlarged schematic view of the cathode section A of FIG. 1. The cathode section is composed of a cathode composed of a cathode material 9, a cathode cap 13 and a sleeve 11, and grid electrodes G1 and G2 parts. . The sleeve 11 is supported by a ceramic disk 12 and a cathode pin disk 14. The cathode pin disk 14 is arranged on the V-tab 10.

After the inside of the picture tube is evacuated as described above, the metal parts used in the electron gun, in particular, the grid electrode G1 and G2 parts (FIG. 2) near the cathode are shown in FIG. The surroundings are covered with a high-frequency induction heating coil 15 and a current of about 400 KHz is passed through the coil, so that G1,
By causing an induced current to flow through the G2 part, it is heated to a temperature of 650 to 800 ° C. via the neck tube 4 to release the gas occluded in the metal part. Next, Ef (filament voltage) is set to, for example, 6V1 minute, 8V1 minute, 9.5.
V1min, 10V1min, 14V1min, and 10V1.5
2 and the temperature of the cathode cap 13 shown in FIG. 2 is increased, and as shown in the enlarged view of FIG. (Ba), strontium (S
r), decomposes and activates calcium (Ca) ternary carbonate) 9 to an oxide (oxide) (decomposition activation process).

[0005] The cathode cap 13 is provided at the tip of a sleeve 11 having a V-tab 10 for supporting a cathode pin disk 14 therein. After decomposing and activating the cathode material 9, the tip tube 6 shown in FIG.
Are heated and sealed, removed from the exhaust dolly, and grid electrodes G1, G are applied with Ef applied by an aging process.
A positive voltage is applied to 2 to cause a current to flow, so that electrons can be sufficiently emitted from the surface of the cathode cap 13.

[0006]

In the conventional method for activating an oxide cathode, when the G1 and G2 parts are subjected to high-frequency induction heating, the high-frequency current for high-frequency induction heating flows into the high-frequency induction heating coil 15 at the moment. The magnetic field 8 shown in FIG. 3 is generated, and an eddy current is generated not only in the G1 and G2 parts but also in the sleeve 11, the cathode cap 13 and the cathode material 9 supported by the V-tab 10, 40
Under the condition of resonance at 0 KHz, the sleeve-cap system vibrates, and the cathode material 9 scatters so as to jump up through the holes G1 and G2. Therefore, the cathode material 9
Adhere to the holes G1 or G2, and cause a stray failure or a discharge failure in the final inspection.

An object of the present invention is to provide a method for activating an oxide cathode in which the cathode material does not peel or scatter even when the G1 and G2 parts are subjected to high-frequency induction heating.

[0008]

The object, according to an aspect of the according to the present invention, the step of evacuating the vacuum picture tube having a cathode consisting of a carbonate, a step of pressurizing Netsuho lifting the cathode portion,
Under heating the cathode portion, and a step that Nessu high frequency induction pressure, and a step of decomposing activated oxide the carbonate grid electrode portion that is disposed proximate the cathode by the high-frequency current The problem is solved by an oxide cathode activation method characterized in that:

[0009]

According to the present invention, the cathode is heated and held in advance.
Grid placed in close proximity to this cathode
Since the electrode portion is subjected to high-frequency induction heating by high-frequency current, the internal resistance of the cathode, which affects the magnitude of the eddy current, can be increased in advance. Thereby, the grid electrode part
The eddy current generated in the cathode by the high-frequency current can be suppressed as compared with the case where the cathode portion is not heated and held before the high-frequency induction heating. Therefore, even if the cathode is under the condition of resonance with the high-frequency current, the resonance action can be suppressed to a small extent, so that separation and scattering of the oxide on the cathode surface can be prevented.

In the present invention, it is preferable that the heating of the cathode portion, especially the cathode cap portion, is performed at a temperature of 400 ° C. or more for at least one minute or more in order to more effectively suppress resonance caused by high-frequency induction heating performed later. .

[0011]

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

First, a panel 1 coated with a fluorescent screen and a funnel 3 are joined together with a frit 2 as in the prior art, an electron gun 5 is inserted into a neck tube 4, and sealed by heating with a gas burner. Thereafter, the primary exhaust pressure in the picture tube 20 is set to 10 ^-3 to 10 ^-4 Torr by a rotary pump, and the inside of the picture tube is evacuated to 10 ^-4 to 10 ^-5 Torr by a diffusion pump.

Next, a filament voltage (Ef) is applied at, for example, 4 V, and the temperature of the cathode cap 13 to which the cathode oxide (BaO or the like) is attached is raised to 450 ° C.
While holding for about one minute, as shown in FIG.
Approximately 40 for high frequency heating coil 15 around 1, G2 parts
A current of 0 KHz is applied, and the gas is heated to about 700 ° C. to release the gas occluded in the metal part. Thereafter, similarly to the conventional process, the temperature of the cathode cap 13 is increased to decompose and activate the respective carbonates of Ba, Sr, and Ca, which are the cathode materials, into oxides. In this example, the cathode material hardly peeled off or scattered, resulting in no stray failure or discharge failure.

[0014]

As described above, according to the present invention,
With the cathode section heated and held in advance,
The grid electrode placed close to
Since high-frequency induction heating is performed, the internal resistance of the cathode, which affects the magnitude of the eddy current, can be increased in advance.
As a result, compared to a case where the cathode portion is not heated and held before the grid electrode portion is subjected to high frequency induction heating ,
Thus, eddy current generated in the cathode can be suppressed. Therefore, even if the cathode is in the resonance conditions the high frequency current, it is possible to suppress the resonance effect, the peeling of the oxide of the cathode surface, it is possible to prevent the scattering, resonance during high frequency induction heating Stray failure and discharge failure due to the phenomenon can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a picture tube (CRT) according to the present invention.

FIG. 2 is an enlarged schematic view of a cathode portion (A) of FIG.

FIG. 3 is a schematic diagram in which a high-frequency induction heating coil is arranged around a cathode portion.

FIG. 4 is a view showing a state in which a cathode material is separated and scattered by resonance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Panel 2 Frit 3 Funnel 4 Neck tube 5 Electron gun 6 Chip tube 8 Magnetic field 9 Cathode material (oxide) 10 V tab 11 Sleeve 12 Ceramic disk 13 Cathode cap 14 Cathode pin disk 15 High frequency induction heating coil 20 Picture tube

Claims (1)

(57) [Claims] And 1. A process for evacuating the picture tube in a vacuum having a cathode consisting of a carbonate, a step of pressurizing Netsuho lifting the cathode part, under heating the cathode portion, in proximity to the cathode oxide cathode active method characterized by comprising the steps that Nessu high frequency induction pressurized by arranged the high-frequency current to the grid electrode portions, and a step of decomposing activated oxide the carbonate.