JPH04315733A - Manufacture of color cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent destruction of a cathode and a heater and also to enhance knocking effects through the application of a high voltage by providing common floating potential to a G1 electrode, a G2 electrode, the cathode and the heater, and subjecting them to high-voltage processing. CONSTITUTION:A G4 electrode 1 is connected to a dc extra-high voltage power supply 9 and a G3 electrode 2 is given earth potential and a G2 electrode 3, a G1 electrode 4, a cathode 5 and a heater 6 are given common floating potential and a resistance R is brought as near to the electrodes as possible and connected to the electrodes 1, 2. When a high voltage is applied to the electrode 1 the voltage is added exclusively to the electrode 2, and evaporated Ba and impurities attached to near the electron-beam through hole of the electrode 2 and the electrode surface can be removed, so that stray emission is hard to occur; i.e., because the electrodes 3, 4, the cathode and the heater are all given common floating potential, no voltage due to creep discharge is applied to the electrodes and the rate of damaging to the cathode and the heater is reduced, whereby the reliability of a color cathode-ray tube can be enhanced.

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 color cathode ray tube with improved voltage resistance characteristics of an electron gun.

0002

2. Description of the Related Art As is well known, in the manufacture of color cathode ray tubes, a spot knocking process is generally performed in the process after evacuation.

This spot knocking process involves applying a voltage higher than the highest voltage value used when a color cathode ray tube is installed in a TV set to the electrodes of the electron gun assembly to forcibly generate a discharge (spark) within the tube. This is done to remove deposits (dust, evaporated substances, dirt, etc.) from the surface of each electrode, and to improve withstand voltage characteristics.

FIG. 3 is a block diagram of an electron gun assembly for explaining an example of a spot knocking process employed in a conventional color cathode ray tube manufacturing method. This figure shows an example of an electron gun assembly enclosed in the neck tube of a high-focus color cathode ray tube.

[0005] During normal use, 1 is about 25KV
2 is a G3 electrode that forms a focusing electron beam; 3 is a G2 electrode that is applied with a voltage of about 700 V to accelerate the electron beam; 4 is a G2 electrode that accelerates the electron beam;
1 electrode, 5 is a cathode electrode, and 6 is a heater, these electrodes 1 to 6 are arranged at a predetermined distance from each other, are held and fixed to at least two bead glasses 7, and are the same as the neck tube 8. placed on the axis.

[0006]

[Problems to be Solved by the Invention] In the high focus type electron gun assembly constructed in this way, the G3 electrode 2 serving as the focus electrode has a higher applied voltage during actual use than the conventional BPF type. Withstanding voltage failure (referred to as stray emission failure) caused between the G3 and G4 electrodes,
Also, the amount of leakage current between the G3 electrode and the G4 electrode was a problem.

That is, during the cathode decomposition in the exhaust process of the color cathode ray tube or during aging, the cathode 5 is heated to about 1000° C. for about 60 minutes, so that the component Ba evaporates from the cathode 5. and adheres to G3 electrode 2, resulting in a smaller work function and G3
Stray emissions were likely to occur due to the electric field between the electrode and the G4 electrode.

Of course, a knocking position is provided before and after the aging process, and as shown in the figure, a DC high voltage power supply 9 is connected to the G4 electrode 1, and a high voltage of 45KV to 60KV is applied to the G4 electrode 1. and the other electrode,
In other words, G3 electrode 2, G2 electrode 3, G1 electrode 4, cathode 5, and heater 6 were grounded to perform knocking treatment between G4 electrode 1 and G3 electrode 2.
In other words, voltage was applied to the G2 electrode, G1 electrode, cathode, and heater due to creeping discharge, and the cathode and heater were likely to be destroyed.

[0009] This invention was invented in view of the above-mentioned problems, and the cathode and heater are not destroyed.
Another object of the present invention is to provide a color cathode ray tube that can increase the knocking effect by applying a high voltage.

0010

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a predetermined high voltage is applied between the G4 electrode and the G3 electrode constituting the electron gun of a color cathode ray tube, and the other electrode It is characterized by high voltage processing with the G1 electrode, G2 electrode, cathode, and heater at a common floating potential.

[0011]

[Operation] According to the present invention, since the G2 electrode, G1 electrode, cathode, and heater that make up the electron gun of the color cathode ray tube have a common floating potential, no voltage is applied to these electrodes due to creeping discharge. Damage to the cathode and heater can be reduced. Therefore, a decrease in reliability due to damage to the cathode or heater can be prevented, and the reliability of the color cathode ray tube can be greatly improved.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an electron gun structure for explaining an embodiment of the spot knocking process adopted in the method for manufacturing a color cathode ray tube according to the present invention. In the figure, the same reference numerals as in FIG. 3 showing the conventional example are , the same or corresponding parts will be shown, and detailed explanation thereof will be omitted.

In FIG. 1, the G4 electrode 1 is connected to a DC ultra-high voltage power supply 9, the G3 electrode 2 is set to ground potential, and the G2 electrode 3, G1 electrode 4, cathode 5 and heater 6 are set to a common floating potential. 1 and G3 electrode 2
400KΩ to 1.0MΩ as close to the electrode as possible.
Attach resistor R.

In the circuit as described above, the G4 electrode 1
When a high voltage of Max 80KV is applied to the G3 electrode 2, the voltage is concentrated on the G3 electrode 2, and the evaporated Ba and impurities attached to the area around the electron beam passage hole of the G3 electrode 2 and the electrode surface can be removed, thereby preventing the occurrence of stray emissions. less likely to occur.

FIG. 2 is a block diagram of an electron gun assembly for explaining another embodiment of the spot knocking process employed in the method for manufacturing a color cathode ray tube according to the present invention, and shows a reverse seasoning method as shown in the figure. Even if applied to Figure 1
Effects similar to those of the embodiment shown in can be obtained.

[0016] The spot knocking process exemplified in the above embodiment can be set at a knocking position on the online conveyor, and is used to remove evaporated Ba deposited during aging and conductive foreign matter such as burrs on the G3 electrode. can be carried out much more effectively than conventional methods. As a result, defects due to breakdown voltage defects caused by the G3 electrode and damage to the cathode and heater can be reduced by about 95% compared to the conventional method.

【Effect of the invention】

As explained above, according to the present invention, G
It is possible to remove the source of stray emissions attached to the three electrodes, and also to suppress the decrease in reliability due to damage to the cathode and heater, greatly improving the reliability of color cathode ray tubes as products. be able to.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an electron gun assembly for explaining an embodiment of a spot knocking process employed in a method of manufacturing a color cathode ray tube according to the present invention.

FIG. 2 is a configuration diagram of an electron gun assembly for explaining another embodiment of the spot knocking process employed in the method of manufacturing a color cathode ray tube according to the present invention.

FIG. 3 is a configuration diagram of an electron gun assembly for explaining an example of a spot knocking process employed in a conventional color cathode ray tube manufacturing method.

[Explanation of symbols]

1 G4 electrode 2 G3 electrode 3 G2 electrode 4 G1 electrode 5 Cathode 6 Heater 7 Bead glass 8 Neck pipe 9 High voltage power supply R resistance

Claims (1)

[Claims] 1. A method for manufacturing a color cathode ray tube having an electron gun including at least a G1 electrode, a G2 electrode, a G3 electrode, a G4 electrode, and a cathode, including the G4 electrode and the G4 electrode.
A predetermined high voltage is applied between the three electrodes, and the other electrode G1
A method for manufacturing a color cathode ray tube, characterized in that electrodes, G2 electrodes, cathodes, and heaters are subjected to high voltage treatment with a common floating potential.