JPH08190855A - Manufacture of cathode-ray tube - Google Patents

Abstract

PURPOSE: To manufacture a cathode-ray tube causing no discharge in operation with good productivity by performing an evaporated film forming process after spot knocking treatment. CONSTITUTION: After a first spot knocking treatment process, an evaporated film forming process is performed. In the first spot knocking treatment process, low voltage electrodes such as a G3 electrode 6, a G2 electrode 7, and a G1 electrode 8 are grounded, respectively, and a high voltage having prescribed waveform and frequency is applied from an anode button to a G4 electrode 5 through an internal conductive film 2, a contact spring 3, and a shield cup 4. The discharge between electrodes in the opposed parts of the G4 electrode 5 and the G3 electrode 6 and the creeping discharge on the inner wall surface of a neck tube and the surface of a bead glass 10 are generated to remove a stray emission generating source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for improving withstand voltage characteristics of a cathode ray tube.

[0002]

2. Description of the Related Art Recently, color cathode ray tubes are required to have improved screen brightness and focus performance. Therefore, the transmittance of the shadow mask is improved, the luminous efficiency of the phosphor is improved, and the operating voltage is increased along with the increase of the electron beam current, and it is essential to improve the withstand voltage characteristics. In particular, the withstand voltage characteristic of a cathode ray tube has a large effect on emission characteristics and life, and an increase in operating voltage may cause deterioration of withstand voltage characteristic. Improvements have become important.

Conventionally, stray emission and discharge in a tube, which are symptoms of deterioration of withstand voltage characteristics, are mainly based on unnecessary electrons due to field emission and secondary electron emission, so that voltage, current, waveform, etc., of spot knocking processing. And suppression of the electric field multiplication factor by improving the shape of the electrode of the electron gun,
The mainstream was to remove stray emission sources. Further, since the in-tube discharge during operation cannot be prevented or suppressed by the above means, the electron gun structure has been improved.

FIG. 6 is a cross-sectional view showing an example of an electron gun housed in the neck portion of a cathode ray tube. 1 is a neck portion of the cathode ray tube, 2 is an internal conductive film to which a high voltage is applied, and 3 is an interior. Contact springs 4 that come into contact with the conductive film 2, 4 are shield cups to which the contact springs 3 are attached, and 5 are fourth shields connected to the shield cups 4 to which a high voltage is applied.
Grating (G4) electrode, 6 is a third grating (G3) electrode that forms an electric field lens with G4 electrode 5, 7 is a second grating (G2) electrode that accelerates and controls the electron beam, and 8 is a first grating (G
1) Electrodes, 9 is a cathode electrode, and 10 is a bead glass for insulating and holding each electrode.

The electron gun constructed in this manner has a voltage of 25 to 35 KV applied to the G4 electrode 5, a voltage of 20% to 30% of the applied voltage of the G4 electrode 5 applied to the G3 electrode 6, and a voltage applied to the G2 electrode 7 of 200% applied during operation. A voltage of 1000 V is applied to each and the G1 electrode 8 is grounded. At this time, the electric potential of the inner wall surface of the neck portion 1 and the surface of the bead glass 10 is charged to a high electric potential due to its volume resistivity, surface conductivity, dielectric constant, etc., and the low voltage electrodes such as the G1 electrode 8 and the like are shown. The electric field strength between the non-stem and inner leads is extremely high,
Electrons due to field emission are generated from the fine projections of the low-voltage electrode or the portion toward the inner wall surface of the neck tube 1 and the surface of the bead glass 10, and secondary electrons are generated on the surface of the glass due to the collision of the electrons, The secondary electrons grew to generate in-tube discharge.

Since it is necessary to prevent the growth of secondary electrons in order to suppress such a discharge in the tube, conventionally, a part of the surface of the bead glass 10 is metallized or a conductive film is applied. And as shown in FIG.
The conductive member 11 connected to the G3 electrode 6 is attached to the bead glass 1
0 is arranged so as to surround 0, and further, the conductive member 11
The metal itself or the metal adhered to the surface of the conductive member 11 by plating or the like is evaporated by high frequency heating or the like to form a vapor deposition film 12 on the surface of the bead glass 10 and the inner wall surface of the neck tube 1 to control the surface potential. A method has been proposed, and is disclosed in JP-A-62-128417 and JP-B-63-10859.
The effects are described in detail in Japanese Patent Publications and the like.

FIG. 7 is a flow chart of a cathode ray tube manufacturing process including a conventional vapor deposition film forming process. A vapor deposition film forming process 15 is provided after the exhaust process 14, and then a spot knocking treatment process 16 for the first time and a cathode activation process are performed. The process 17 for the oxidization, the process 18 for the second spot knocking process, and the process 19 for the inspection were performed in this order.

[0008]

In the conventional manufacturing method,
Since the vapor deposition film 12 is formed on the inner wall surface of the neck tube 1 and the surface of the bead glass 10 at the time of the first spot knocking process, at the time of the first spot knocking process, the high voltage portion (the internal conductive film 2 and the shield cup 4). , G4 electrode 5) and the vapor-deposited film 12 or the conductive member 11 are concentrated, and the inter-electrode discharge at the opposing portion of the G4 electrode 5 and the G3 electrode 6 is suppressed. Could not be done.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to perform sufficient conditioning without causing problems such as stray emission, and to discharge in a tube during operation. The object is to obtain a method for manufacturing a cathode ray tube that does not cause

[0010]

In the method of manufacturing a cathode ray tube according to the present invention, a vapor deposition film is formed after performing spot knocking treatment.

Further, the vapor deposition film is formed after the spot knocking process and the cathode activation process.

Further, the lattice electrode is heat-treated at the same time as the formation of the vapor deposition film.

[0013]

According to the present invention, since the spot knocking treatment is performed before forming the vapor deposition film on the inner wall of the neck tube and the surface of the bead glass, the stray emission source can be effectively removed, and the discharge in the tube during operation can be prevented. It is possible to obtain a cathode ray tube that does not occur.

Further, since the spot knocking process and the cathode activation process are performed before forming the above vapor deposition film,
Active B deposited on the grid electrode in the cathode activation process
a can be effectively removed or inactivated.

Further, since the lattice electrode is heat-treated at the same time when the vapor-deposited film is formed, the active Ba vapor-deposited on the lattice electrode in the cathode activation step can be more effectively removed or inactivated.

[0016]

【Example】

Example 1. The first embodiment of the present invention will be described below. FIG. 1 is a flow chart of the manufacturing method of Example 1, and the same reference numerals as those in FIG. 7 indicate the same steps, respectively. After performing the first spot knocking treatment step 16, the vapor deposition film forming step 15 is performed. It was done. In the first spot knocking process 16, the low voltage electrodes such as the G3 electrode 6, the G2 electrode 7 and the G1 electrode 8 are grounded respectively, and the inner conductive film 2, the contact spring 3 and the shield cup 4 are connected to the anode button (not shown). A high voltage having a predetermined waveform and frequency is applied to the G4 electrode 5 via
The stray emission generation source is removed by generating an inter-electrode discharge at the opposing portions of the 4th electrode 5 and the G3 electrode 6 and a creeping discharge on the inner wall surface of the neck tube 19 and the surface of the bead glass 10.

FIG. 2 is a diagram comparing the stray emission generation voltage of the first embodiment and the conventional example, in which the stray emission generation voltage is plotted on the Y axis. As a matter of course,
The higher the stray emission generation voltage is, the better.
The stray emission generation voltage of is higher than that of the conventional example, and the variation is smaller. In the first embodiment, the high voltage part of the electron gun (the internal conductive film 2, the shield cup 4, the G4 electrode 5, etc.), the vapor deposition film 12 and the conductive member 11 are used.
Neck part 1 and bead glass 1 due to discharge concentration between
Dielectric breakdown of 0 does not occur.

Example 2. In the first embodiment, the case where the vapor deposition film 12 is formed after the first spot knocking treatment is shown. However, in order to remove the stray emission source generated in the cathode activation step 17 of the next stage, As shown in the flowchart of FIG. 3, the vapor deposition film forming step 15 may be performed after the first spot knocking treatment step 16, the cathode activation step 17, and the second spot knocking treatment step 18.

In the cathode activation step 17, a large amount of Ba evaporates from the cathode electrode 9 and, as shown in FIG.
Deposition is performed around the apertures of the electrode 7 and the G1 electrode 8. This vapor-deposited Ba13 easily serves as a source of stray emission, and in particular, the fact that Ba13 vapor-deposited on the G2 electrode 7 is activated causes the voltage of the G3 electrode 6 in the operating state to be 20% of the voltage of the G4 electrode 5. Since it is as high as -30%, stray emission due to field emission is likely to occur. In the second embodiment, the second spot knocking process step 18 is performed.
Since an effective discharge occurs as described above at
13 is removed or is inactivated by the adsorbed gas or the occluded gas in the electrode released by the discharge, and the function as the stray emission source can be reduced.

Example 3. FIG. 4 is a flow chart of a third embodiment of the present invention. In addition to the second embodiment, the G2 electrode 7 is heated and vapor-deposited by the high frequency heating method simultaneously with the formation of the vapor-deposited film.
It is adapted to be re-evaporated and removed by heating above the evaporation temperature of a13. Even if the heating temperature is lower than the temperature required for re-evaporation, Ba13 can be inactivated by the gas discharged from the electrode, which is effective.

FIG. 5 is a diagram comparing the stray emission generation voltage from the G2 electrode 7 of the third embodiment and the conventional example.
A stray emission generation voltage from the G2 electrode 7 is taken on the axis. As is clear from FIG. 5, in the third embodiment, the stray emission generation voltage is greatly improved and the variation is small.

In the third embodiment, after the cathode activation process and the spot knocking process of the second embodiment are performed, the grid electrode is heated at a high frequency at the same time when the deposited film is formed.
After performing the spot knocking treatment of the first embodiment, the grid electrode may be heated at a high frequency at the same time when the vapor deposition film is formed, and the stray emission from the grid electrode can be reduced.

Incidentally, in the conventional example, the spot knocking treatment is performed again for the product having the stray emission generation voltage of the specified voltage or less, but according to each of the above-mentioned embodiments, the number of the re-spot knocking treatments is reduced. As a result, the straight line rate is improved and the number of defective products is reduced, resulting in a significant improvement in productivity. Further, the original effect of the vapor-deposited film 12 was not impaired at all, and the discharge characteristics during operation could be obtained as the conventional performance.

[0024]

As described above, according to the present invention, since the vapor deposition film is formed after the spot knocking treatment is performed, the conditioning by the spot knocking can be effectively performed, which is preferable. A cathode ray tube that has stray emission characteristics and does not generate discharge during operation can be manufactured with high productivity.

Further, since the spot knocking treatment is performed after the cathode activation step and the vapor deposition film is formed, the active Ba vapor deposited on the lattice electrode can be removed or inactivated. , The stray emission characteristics are improved.

Further, since the grid electrode is heated at a high frequency at the same time as the formation of the deposited film, the active Ba deposited on the grid electrode can be removed or inactivated, and the stray emission characteristics are further improved. .

[Brief description of drawings]

FIG. 1 is a flowchart of a manufacturing method according to a first embodiment of the present invention.

FIG. 2 is a comparison diagram of stray emission generation voltage according to the first embodiment.

FIG. 3 is a flowchart of a manufacturing method according to a second embodiment of the present invention.

FIG. 4 is a flowchart of a manufacturing method according to a third embodiment of the present invention.

FIG. 5 is a comparison diagram of stray emission generation voltage from the G2 electrode of Example 3;

FIG. 6 is a sectional view of a neck portion of a cathode ray tube having a conventional vapor deposition film.

FIG. 7 is a flowchart of a manufacturing method of a conventional example.

[Explanation of symbols]

1 neck part, 4 shield cup, 5 G4 electrode, 6
G3 electrode, 7 G2 electrode, 8 G1 electrode, 9 cathode electrode, 10 bead glass, 11 conductive member, 12
Deposition film, 13 Deposition Ba.

Claims (3)

[Claims] 1. A grid of the electron gun surrounding the outer surface of the bead glass holding each electrode of the electron gun housed in the neck portion of the cathode ray tube and being interposed between the bead glass and the inner wall surface of the neck portion. A step of depositing a vapor deposition film on the inner wall surface of the neck portion facing the annular conductive member by heating and evaporating the annular conductive member connected to the electrode, and a cathode ray tube including a spot knocking treatment step A method of manufacturing a cathode ray tube, characterized in that, in the manufacturing method, the vapor deposition film forming step is performed after the spot knocking processing step. 2. The method of manufacturing a cathode ray tube according to claim 1, wherein the vapor deposition film forming step is performed after the cathode activating step. 3. The method of manufacturing a cathode ray tube according to claim 1, wherein a specific electrode is heated at the same time when the vapor deposition film is formed to remove the stray emission source.