JP2002367515A - Manufacturing method for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a drop of electron emission form a cathode in the initial period of the operation of a cathode-ray tube. SOLUTION: The manufacture of the cathode-ray tube comprises a current activation process for the cathode-ray tube using an electron gun in which a cathode 2, a control electrode 3, an accelerating electrode 4, a modulation electrode 5 and a convergence electrode 6 are installed in this order from the cathode 2 side, wherein the current activation process includes a first process in which the accelerating electrode 4 is irradiated with an electron beam y impressing a higher voltage than the cathode voltage to the accelerating electrode 4 and a second process in which the modulation electrode 5 is irradiated with electron beam by impressing a higher voltage than the cathode voltage to the modulation electrode 5.

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 having a modulation electrode.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a schematic cross-sectional view of an electron gun used for a high-resolution cathode ray tube as disclosed in Japanese Patent Application Publication No. 8 and capable of controlling an electron flow using a low-voltage and inexpensive integrated circuit. Where 1 is a heater, 2
Is a cathode, 3 is a control electrode (hereinafter referred to as G1 electrode),
4 is an accelerating electrode (hereinafter, referred to as G2 electrode), 5 is a modulation electrode (hereinafter, referred to as Gm electrode), 6 is a focusing electrode (hereinafter, G3 electrode).
7) High-voltage electrode (hereinafter referred to as G4 electrode)
Is shown. In such an electron gun, the G2 electrode 4 and G3
A feature is that a Gm electrode 5 is further provided between the electrodes 6, and other electrodes such as a G4 electrode have the same structure as an electron gun without the Gm electrode 5.

Here, the Gm electrode 5 will be described. In the operation of a normal cathode ray tube, a voltage of about +100 V is applied to the Gm electrode 5 with respect to the G1 electrode 3 and the G2 electrode 4
, Several hundred volts are applied. The video signal is applied as a cathode voltage, which is a positive voltage with respect to the voltage of the G1 electrode 3, and a maximum of about 100 V is applied. G2
Since the voltage of the Gm electrode 5 is set lower than that of the electrode 4, not all of the electron current emitted from the cathode 2 flows to the screen, but part of the electron current flows into the G2 electrode 4 or the Gm electrode 5. FIG. 2 is a schematic diagram showing a path of an electron flow emitted from the cathode 2 in a cathode ray tube operation state of the electron gun, and electrons are transmitted from the Gm electrode 5 side of the G2 electrode 4 to the Gm electrode 5 side.
This shows that the gas flows into both surfaces of the electrode 3 and the surface of the Gm electrode 5 facing the G2 electrode 4.

Next, the structure of the cathode 2, the G1 electrode 3, the G2 electrode 4, and the Gm electrode 5 will be described. Usually, the diameter of the electron passage holes of the G1 electrode 3 and the G2 electrode 4 is about φ0.4 m.
The hole diameter of the m and Gm electrodes 5 is set to φ0.1 mm. Further, the respective electrodes are arranged at intervals of 0.1 to 0.3 mm.

In the electron gun having such a structure, the hole diameter of the Gm electrode 5 is set smaller than the hole diameters of the G1 electrode 3 and the G2 electrode 4, and the voltage of the Gm electrode 5 is set lower than that of the G2 electrode 4. The reason is that a part of the electrons emitted from the cathode 2 is taken into the Gm electrode 5 and the G2 electrode 4 so that the electron flow toward the screen is efficiently controlled by a low-voltage driven cathode voltage power supply.

Next, a conventional manufacturing process of a cathode ray tube disclosed in Japanese Patent Application Laid-Open No. 11-224618 will be described with reference to FIG. First, an electron gun is mounted inside a glass tube integrally formed with a screen for displaying an image, and the glass tube is sealed through an evacuation process for evacuating the inside of the glass tube. Further, in order to obtain the electron emission capability of the cathode itself, it is possible to extract a sufficient electron flow from the cathode only after the activation step.

Here, the conventional activation step will be described in detail. The activation process is broadly divided into a heat activation process and a current activation process. The main purpose of the thermal activation process is to obtain the electron emission capability of the cathode itself. This is performed for the purpose of improving the radiation ability and discharging gas from the G1 electrode 3, the G2 electrode 4, and the Gm electrode 5.

The electron emission from the cathode is liable to be deteriorated due to gas poisoning due to its nature, and is easily affected by gas emitted from the G1, G2, and Gm electrodes 5 during operation of the cathode ray tube. . In particular, in the electron gun disclosed in Japanese Patent Application Laid-Open No. H11-224618 having the Gm electrode 5, a part of the electron current is taken into the G2 electrode 4 and the Gm electrode 5 during operation. Outgassing is likely to occur due to the energy of the collision.

Therefore, the G2 electrode 4, G during operation of the cathode ray tube
In order to suppress outgassing from the m-electrode 5, a positive voltage with respect to the cathode voltage is applied to the G2 electrode 4 and the Gm electrode 5 in advance when the current is activated in the cathode ray tube manufacturing process, and the electron beam is irradiated, thereby forcibly. To complete the gas release. In this case, in the conventional current activation process, G
A method of short-circuiting the two electrodes 4 and the Gm electrode 5 and irradiating the G2 electrode 4 and the Gm electrode 5 with an electron flow by, for example, applying a voltage of +300 V to the cathode voltage to expel the adsorbed gas has been adopted. .

[0010]

As described above, in the method of manufacturing a cathode ray tube in which the Gm electrode 5 is provided between the G2 electrode 4 and the G3 electrode 6, the conventional method is consistent with the current activation during the activation step. In this method, the G2 electrode 4 and the Gm electrode 5 were short-circuited and the electron current was irradiated.
Electron current does not flow evenly to both of the electrodes 5, and in particular, the irradiation of the electron current to the G2 electrode 4 having a large electron passage hole diameter becomes insufficient and gas cannot be sufficiently released. There was a tendency for significant reduction in electron emission capability.

[0011]

A method of manufacturing a cathode ray tube according to the present invention uses an electron gun in which a cathode, a G1, G2, Gm, and G3 electrode are arranged in this order from the cathode side. In the current activation step of the cathode ray tube, a first step of applying a voltage higher than the cathode voltage to the G2 electrode to irradiate the G2 electrode with an electron beam, and applying a voltage higher than the cathode voltage to the Gm electrode And a second step of irradiating the Gm electrode with an electron beam.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Embodiment 1 will be described below. In FIG. 1, the structure of the electron gun is the same as that of the conventional example. 1 is a heater, 2 is a cathode, 3 is a G1 electrode, 4 is a G2 electrode, 5 is a Gm electrode, 6 is a G3 electrode, 7 is a G4 electrode, and a Gm electrode 5 is provided between the G2 electrode 4 and the G3 electrode 6. It is characterized by having.

Next, the positional relationship between the electrodes near the cathode will be described. The G1 electrode 3 and the G2 electrode 4 have a diameter of the electron passing hole of 0.4 mm, and the thickness in the axial direction (electron emission axis direction) connecting the electron passing holes of the G1 electrode 3 to the G4 electrode is about 0.1 mm, respectively. . For the Gm electrode 5, the diameter of the electron passage hole is 0.1 mm and the thickness in the electron emission axis direction is 0.0 mm.
5 mm. The distance between the electrodes is about 0.05 mm between the cathode and the G1 electrode 3, and the distance between the G1 electrode 3 and the G2 electrode 4 and between the G2 electrode 4 and the Gm electrode 5 is 0.1 mm.
mm.

Hereinafter, a manufacturing process of the cathode ray tube according to the first embodiment will be described with reference to FIGS. As shown in FIG. 5, an electron gun 13 is inserted into and fixed to an end of a glass tube 12 of a cathode ray tube formed integrally with a screen 11 for displaying an image. This is the electron gun sealing step shown in FIG. Subsequently, in the evacuation step, the gas in the glass tube body 12 is evacuated to a vacuum state and then sealed. In the latter half of the evacuation step, a step of decomposing the electron-emitting material in the cathode is usually provided.
A step of degassing the electrode 4 and the Gm electrode 5 is provided.

Next, the activation step in FIG. 3 will be described. As shown in FIG. 3, the activation step includes two steps, the first is a thermal activation step, and the second is a current activation step, which is performed in this order. The thermal activation step is performed to increase the electron emission capability of the cathode 2, and is the same as the conventional method in which only the heater voltage is applied. In addition, the current activating step improves the electron emission capability of the cathode 2 and increases
The purpose is to discharge gas from the one electrode 3, the G2 electrode 4, and the Gm electrode 5.

The current activation step is further divided into two steps. In the first step, a voltage several hundred V higher than the cathode voltage is applied to the G2 electrode 4 to irradiate the G2 electrode 4 with an electron beam. For example, cathode voltage,
The G1 electrode voltage and the Gm electrode voltage are set to 0 V, and the G2 electrode 4
Is provided with a first step of applying 300 V for 10 minutes.
In the second step, a voltage several hundred V higher than the cathode voltage is applied to the Gm electrode 5 to irradiate the Gm electrode with an electron beam. For example, after the first step, the cathode voltage, G
The second step of setting the one-electrode voltage and the G2 electrode voltage to 0 V and applying 300 V to the Gm electrode 5 for 10 minutes is performed. As described above, the current activation process is divided into the first and second processes, and the outgassing of each electrode is performed with emphasis.

FIG. 6 shows a change in the electron current emitted from the cathode 2 at the initial stage of the operation of the cathode ray tube according to the first embodiment. The horizontal axis represents time, and the vertical axis represents the current from the cathode 2. Is shown. As a conventional example, the G2 electrode 4 and the Gm electrode 5 are short-circuited to the same voltage, and the other electrode voltages are set to the same values as in the first embodiment, and the time of the cathode current in the case where the current activation process is performed for 20 minutes is performed. The changes are shown together.

As can be seen from FIG. 6, G2 electrode 4 and G2
In the first embodiment in which the gas discharge of the m electrode 5 is performed separately,
The result of the change in the electron flow from the cathode was smaller than that in the conventional example in which the G2 electrode 4 and the Gm electrode 5 were short-circuited.

Here, the reason why the change in the cathode current is smaller in the first embodiment than in the conventional example will be described. In the conventional example, a voltage is applied by short-circuiting the G2 electrode 4 and the Gm electrode 5, and the diameter of the electron passage hole is smaller in the Gm electrode 5 than in the G2 electrode 4. It is probable that electrons mainly collided with No. 5 and the G2 electrode 4 was hardly irradiated with electrons, so that outgassing of the G2 electrode 4 was insufficient. On the other hand, in the first embodiment, the first step of degassing the G2 electrode 4 and the second step of degassing the Gm electrode 5 are provided separately. It is conceivable that the gas emission was suppressed by suppressing gas emission from the G2 electrode 4 and the Gm electrode 5 during the operation of the cathode ray tube, and poisoning of the cathode, that is, deterioration of electron emission was reduced.

[0020]

According to the present invention, as described above, in the current activation step, the first step of discharging gas from the G2 electrode 4 and the second step of discharging gas from the Gm electrode 5 are provided. This makes it possible to reduce the change in electron emission from the cathode due to poisoning as compared with the conventional example.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing the structure of an electron gun.

FIG. 2 is a schematic diagram showing a path of an electron flow during operation of a cathode ray tube.

FIG. 3 is an explanatory diagram of a manufacturing process of the cathode ray tube according to the first embodiment.

FIG. 4 is an explanatory view of a conventional manufacturing process.

FIG. 5 is a schematic sectional view for explaining the structure of a cathode ray tube.

FIG. 6 is an explanatory diagram illustrating an effect of the first embodiment.

[Explanation of symbols]

1 heater, 2 cathodes, 3 control electrodes (G1 electrode), 4 accelerating electrodes (G2 electrode), 5 modulation electrodes (Gm
Electrode), 6 focusing electrode (G3 electrode), 7 high voltage electrode (G
4 electrodes), 11 screen, 12 glass tube, 13
Electron gun.

Claims (1)

[Claims] In a current activation step of a cathode ray tube using an electron gun in which a cathode, a control electrode, an acceleration electrode, a modulation electrode, and a focusing electrode are arranged in this order from the cathode side, the cathode is connected to the acceleration electrode. A first step of applying a voltage higher than a voltage to irradiate the acceleration electrode with the electron beam; and a second step of applying a voltage higher than the cathode voltage to the modulation electrode and irradiating the modulation electrode with the electron beam. And a method for manufacturing a cathode ray tube.