JPS6177233A - Manufacture of cathode-ray tube - Google Patents

Abstract

PURPOSE:To suppress discharge inside a tube while reducing generation of electric field emission electrons by generating the discharge plasma around the electron guns in a hydrogen gas atmosphere followed by sealing the electron guns inside a glass bulb. CONSTITUTION:Electron guns 1 are set up inside a vacuum container 21 for performing prescribed connection followed by operating a switching valve 25 for evacuating the inside of the vacuum container 21 by a vacuum evacuation device 24. At a point of time when the inside of the vacuum container 21 is highly vacuumized the switching valve 27 is opened for introducing hydrogen gas into the inside of the vacuum container 21 from a hydrogen gas bomb 26. When high voltage is impressed on the electron guns 1, the discharge plasma is generated through hydrogen gas for cleaning the electrode surfaces. The treated electron guns 1 are taken out from the vacuum container 21 followed by being sealed into the glass bulb.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a cathode ray tube that suppresses internal discharge.

[Conventional technology] FIG. 5 is a schematic diagram showing the structure of a general cathode ray tube.

In the figure, (1) is the low voltage electrode (2a), (2h)
, (2c), an electron gun consisting of a focusing electrode (3) and an anode (4), (5) a glass bulb that houses this electron gun (1) and whose interior is kept in a high vacuum, (8) is a conductive film painted on the inner surface of this glass bulb (5), (7) is a high voltage power supply connected to this conductive film (8), and (8) is the low voltage electrode (2a), (2b), ( 2c) and a control power source for supplying voltage to the focusing electrode (3), (9
) indicates field emission electrons from the high-field electrode portion, and (11) indicates the cathode ray tube body.6 Next, the operation will be explained. Low voltage electrode (2a).

Electron beams are generated in parts (2b) and (2c), and their intensity is controlled. A certain positive voltage is applied to the focusing electrode (3), and a positive high voltage is applied to the anode (4) to focus the electron beam.

At this time, field emission electrons (8) as shown in FIG. 5 are generated from the ends of the focusing electrode (3) and the low voltage electrode (2c), which produce a high electric field of negative polarity. This field emission electron - (8
) increases, it induces intraluminal discharge. In order to suppress this intraluminal discharge, it is necessary to suppress the generation of field emission electrons (9). It is thought that field emission electrons (8) are likely to be generated from minute protrusions or impurities on the electrode surface.

[Problems to be Solved by the Invention] By the way, as shown in FIG. 4, the conventional method for manufacturing a cathode ray tube includes the following steps: Step A to assemble the electron gun, and install the assembled electron gun inside the glass bulb of the cathode ray tube. It consists of process D, process E for vacuum evacuation of the glass bulb, process F for seasoning by applying high voltage, and process G for adjusting and checking the operation. Because the electron gun was mounted in the glass bulb of the cathode ray tube as it was during the manufacturing process, it was not possible to sufficiently clean the electrode surface of the electron gun, making it difficult to suppress discharge inside the tube. Ta.

The present invention has been made in order to overcome the above-mentioned drawbacks of the conventional art, and an object of the present invention is to provide a method for manufacturing a cathode ray tube in which the generation of field emission electrons is reduced and internal discharge is suppressed.

[Means for Solving the Problems] The present invention sets an electron gun in a vacuum container before being sealed in a glass bulb and evacuates it, and then introduces hydrogen gas into the vacuum container. The method is characterized in that the electrode surface of the electron gun is treated by generating discharge plasma around the electron gun in a hydrogen gas atmosphere, and then the electron gun is taken out of the vacuum container and sealed in a glass bulb.

[Operation] In this invention, by generating discharge plasma around the electron gun, excited or ionized hydrogen molecules collide with the electrode of the electron gun, and the kinetic energy at this time removes impurities on the electrode surface. Expelled, also the electrode surface! Since the oxide layer is removed by causing a reduction reaction with the - oxide layer, the impurities and oxide layer that cause field emission electrons are reduced.

[Example 1 Embodiments of the invention will now be described with reference to the drawings.

FIG. 1 shows an example of the manufacturing process of a cathode ray tube according to the present invention. Compared to the conventional one shown in Fig. 4, after assembling the electron gun, step B involves setting the electron gun in a vacuum container and performing vacuum evacuation, and after evacuation, hydrogen gas is filled in and discharge is performed.
A new section T and C for taking out the electron gun has been added.

FIG. 2 shows an example of the process of performing discharge. In the figure, (21) is a vacuum vessel in which the electron gun (1) is attached, (
22) is an electron gun (1) set in a vacuum container (21)
(23) is a high-voltage power supply, (24) is a vacuum evacuation device for evacuation of the vacuum container (21), (25) is an on-off valve for evacuation, (
26) is a hydrogen gas cylinder, and (27) is an on-off valve for introducing hydrogen gas.

Next, a method for treating the electrode surface will be explained.

Place the assembled electron gun (1) in the vacuum container (21),
After making the predetermined connections, the on-off valve (25) is operated to evacuate the inside of the vacuum container (21) using the vacuum evacuation device (24). When the inside of the vacuum container (21) becomes high vacuum,
The on-off valve (27) is opened and hydrogen gas is introduced into the vacuum container (21) from the hydrogen gas cylinder (26). and,
A high voltage is then applied to the anode (4) of the electron gun (1).

The applied voltage may be direct current, alternating current, or pulsed.

When high voltage is applied to the electron gun (1), hydrogen gas connects the anode (4) and the focusing electrode (3), and the anode (4) and the low-voltage electrodes (2a), (2b), (2c). A discharge occurs between the two, producing discharge plasma. In a discharge plasma in hydrogen gas, hydrogen molecules are excited or ionized,
It collides with the electrode of the electron gun (1). The kinetic energy at this time drives out impurities on the electrode surface, and also causes a reduction reaction with the oxide layer on the electrode surface to remove the oxide layer.
Clean the electrode surface. This results in field emission electrons (9)
Since the impurities and oxide layer that cause the generation of field emission electrons (9) are reduced and the generation of field emission electrons (9) can be suppressed, a highly reliable cathode ray tube with less internal discharge can be manufactured.

Note that the electron gun (1) processed as described above is taken out from the vacuum container (21) and then sealed in a glass bulb in the same manner as before.

- In the embodiment described above, a high voltage was applied to the anode (0), but the anode (4) was grounded and passed through the pin terminal on the low voltage side to the converging electrode (3) or the low voltage electrode (2a), (2b).
, (2c) may be applied with a high voltage.

FIG. 3 shows another embodiment of the invention.

In this embodiment, a coil (28
), and a high frequency power source (28) is connected to this coil (28).
A high-frequency current is supplied from the electrode to generate discharge plasma around the electrode.

In the case of Fig. 3, a high frequency magnetic field is applied to the electron gun (1), but instead of this, for example, a high frequency electric field from parallel plate electrodes or a high frequency electromagnetic field from a traveling wave tube may be applied. A similar discharge plasma can also be generated.

[Effects of the Invention] As described above, according to the present invention, the electrode surface of the electron gun is cleaned by discharge plasma, and as a result, impurities and oxide layers that cause field emission electrons are reduced, and as a result, tube discharge is reduced. A highly reliable cathode ray tube manufacturing method can be provided.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the manufacturing process of a cathode ray tube according to the present invention;
Fig. 2 is a diagram showing the discharge process in the present invention, Fig. 3 is a diagram showing another example of the discharge process, Fig. 4 is a diagram showing the manufacturing process of a conventional cathode ray tube, and Fig. 5 is a general diagram. 1 is a schematic cross-sectional view showing the structure of a typical cathode ray tube. (1)...Electron gun, (21)...Vacuum container, (23
)...High voltage power supply, (24)...Vacuum exhaust device, (2
B)...Hydrogen gas cylinder, (28)...Coil, (
28)...High frequency power supply. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (3)

[Claims] (1) After setting the electron gun in a vacuum container and evacuating it before it is sealed in the glass bulb, hydrogen gas is introduced into the vacuum container, and the surroundings of the electron gun are placed in this hydrogen gas atmosphere. 1. A method for manufacturing a cathode ray tube, which comprises treating the electrode surface of an electron gun by generating discharge plasma, and then taking the electron gun out of the vacuum container and sealing it in a glass bulb. (2) A method for manufacturing a cathode ray tube according to claim 1, in which discharge plasma is generated by applying a high voltage to an anode, a focusing electrode, or a low-voltage electrode of an electron gun. (3) A method for manufacturing a cathode ray tube according to claim 1, in which discharge plasma is generated by applying a high frequency magnetic field or a high frequency electric field to an electron gun.