JPH0778565A - Withstand voltage processing method for cathode-ray tube - Google Patents

Abstract

PURPOSE:To apply a withstand voltage process sufficently by emitting discharge on the low voltage side by providing a discharge gap outside a cathode-ray tube, and applying a high voltage on an intermediate voltage electrode by generated discharge. CONSTITUTION:A discharge gap 50 is provided between a high-voltage input terminal 20 provided at an enclosure of a cathode-ray tube 10 and an intermediate voltage electrode. When generation of discharge between high voltage side electrodes is stopped, discharge is generated in the discharge gap 50. A discharge current flows through a high voltage resistance 54 to apply a high voltage pulse on the intermediate voltage side electrode. The high voltage pulse is applied continuously on the intermediate voltage side electrode using the discharge current at this discharge gap 50, so a withstand voltage process on the low voltage side is performed even after completion of the withstand voltage process on the high voltage side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating withstand voltage of a cathode ray tube, which is carried out after the assembly of the cathode ray tube is completed.

[0002]

2. Description of the Related Art Generally, a cathode ray tube has an envelope composed of a panel having a fluorescent surface formed on the inner surface thereof and a funnel connected to the panel, and a focusing electrode, a final electrode and a final electrode in the neck of the funnel. An electron gun including a plurality of electrodes including an acceleration electrode and the like is provided.

FIG. 3 shows an example of the electron gun. This electron gun includes a heater 11, a cathode 12 and a first grid electrode 1.
3, the second grid electrode 14, the third grid electrode 15, the fourth grid electrode 16, the fifth grid electrode 17, the sixth grid electrode 18, and the convergence electrode 19.
The second grid electrode 14 and the fourth grid electrode 16, and the third grid electrode 15 and the fifth grid electrode 17 are connected in the neck 1, respectively, and a heater voltage is applied to the heater 11, and the first grid electrode 13 Is grounded,
The second grid electrode 14 and the fourth grid electrode 16 have a number 1
The sixth grid electrode 18 is applied with a low voltage of about 00V.
The high-voltage input terminal 20 provided on the funnel 2.
A high voltage of 20 to 30 kV is applied via the (anode button), the internal conductive film 3 provided on the inner surface of the funnel 2, the valve spacer 4 and the convergence electrode 19, and the third grid electrode 15 and the fifth grid electrode 15 are applied. A medium voltage of about 28% of the voltage applied to the sixth grid electrode 18 is applied to 17. Therefore, in this electron gun, the first grid electrode 13, the second grid electrode 14, and the fourth grid electrode 16 are low-voltage side electrodes, the third grid electrode 15 and the fifth grid electrode 17 are medium-voltage side electrodes, and the sixth grid electrode. 18 constitutes the high voltage side electrode as the final acceleration electrode.

Conventionally, a cathode ray tube is subjected to a withstand voltage treatment after the assembly of its manufacturing process is completed. This withstand voltage treatment
This is a method of treating the surface of an electrode by generating a discharge between a plurality of electrodes of an electron gun. Among the plurality of electrodes, a fifth grid electrode 17 is a first grid to which a high voltage is applied from a high voltage input terminal 20. Since it is adjacent to the 6 grid electrode 18,
Sufficient withstand voltage treatment is possible. However, the withstand voltage treatment of the electron gun is necessary not only for the fifth grid electrode 17, but also for the second grid electrode 14 and the fourth grid electrode 16 located on the cathode 12 side of the fifth grid electrode 17.
For that purpose, it is necessary to apply a high voltage also to the third grid electrode 15.

Therefore, some methods have been conventionally proposed for the withstand voltage treatment of the cathode ray tube.

As a first method thereof, Japanese Patent Publication No. 61-38
There is a method called an intermediate electrode float method shown in Japanese Patent No. 571. As shown in FIG. 4, this method includes a heater 11, a cathode 12, a first grid electrode 13, a second grid electrode 14, a third grid electrode 15, a fourth grid electrode 16, a fifth grid electrode 17 and a sixth grid. Electrode 1
8 has a sixth grid electrode 18 having an electron gun configured such that an acceleration high voltage is applied from a high voltage input terminal 20 to a high voltage input terminal 20 from a power source 21. By applying a high voltage and electrically separating, for example, the third grid electrode 15 and the fifth grid electrode 17 as the intermediate electrodes from the other electrodes to make them in a floating state,
A high voltage is applied to these intermediate electrodes. In addition, 22,
Reference numeral 23 is a stable resistor inserted in the power supply circuit, and 30 is a socket connected to the heater 11, the cathode 12, the first grid electrode 13, the second grid electrode 14, the fourth grid electrode 16, and the like. However, this method has a problem that the potential difference between the intermediate electrode and the low-voltage side electrode is not constant, and the applied voltage becomes insufficient.

As a second method, there is a method of directly applying a high voltage to the intermediate electrode as shown in FIG. In the example shown in FIG. 5, the third grid electrode 15 and the fifth grid electrode 17
A high voltage is applied from the power source 24 to the. Normally, the withstand voltage treatment needs to be performed so that a creeping discharge does not occur in the socket 30. Therefore, it is preferable that the applied voltage has a small pulse width. This is because it takes some time until a creeping discharge current flows after a high voltage exceeding a voltage (critical voltage) that causes a creeping discharge is applied to the socket 30. However, in this second method, the applied voltage from the power supply 24 is
Since the waveform has a wide pulse width as shown by the solid line 41 in FIG. 7, there is a problem that the applied voltage is limited by the critical voltage and a sufficiently high voltage cannot be applied.

As a third method, as shown in FIG. 6, a high voltage resistor 28 is inserted between the intermediate voltage side electrodes (the third grid electrode 15 and the fifth grid electrode 17) and other low voltage side electrodes. There is a method of applying a high voltage to the intermediate voltage side electrode by utilizing the voltage drop generated when the discharge current between the fifth grid electrode 17 and the sixth grid electrode 18 flows through the high voltage resistor 28. In addition, 25 is a power supply that generates a high voltage, and 26, 2
Reference numeral 7 is a stabilizing resistor inserted in the power supply circuit. In this method, the voltage waveform applied from the intermediate electrode (intermediate voltage side electrode) to the low voltage side electrode is shown by a broken line 42 in FIG. 7 as compared with the second method in which a high voltage is directly applied to the intermediate electrode. It becomes a sharp pulse. Therefore, even if a high voltage exceeding the critical voltage at which the creeping discharge is generated is applied to the socket 30, the creeping discharge does not occur. Therefore, it is possible to increase the applied voltage and perform effective withstand voltage processing. However, in this method, the application of the high voltage to the low voltage side is restricted due to the discharge between the fifth grid electrode 17 and the sixth grid electrode 18 on the high voltage side, and the number of pulse applications may be insufficient. There's a problem.

[0009]

As described above, there are various conventional methods for treating the withstand voltage of the cathode ray tube. In particular, a high voltage resistor is inserted between the medium voltage side electrode and another low voltage side electrode, and the discharge current between the high voltage side electrode to which the acceleration high voltage is applied and the adjacent medium voltage side electrode is The method (third method) of applying a high voltage to the middle-voltage side electrode by utilizing the voltage drop that occurs when flowing through the high-voltage resistance allows the high voltage to be applied to the middle-voltage side electrode, but When the discharge on the voltage side is completed, the high voltage cannot be applied to the low voltage side, and there is a problem that the number of times of pulse application may be insufficient.

The present invention has been made in view of the above problems, and after the discharge on the high voltage side is completed, a high voltage pulse is applied to the medium voltage electrode to perform the withstand voltage treatment on the low voltage side. An object is to obtain a withstand voltage treatment method that can be sufficiently performed.

[0011]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides an electrode gun electrode having at least a low voltage electrode, a medium voltage electrode and a high voltage electrode disposed in a neck of an envelope. In a withstand voltage treatment method for a cathode ray tube, in which a discharge voltage is applied to the cathode ray tube, a discharge gap for applying a high voltage pulse to a medium voltage electrode is provided outside the cathode ray tube, and the discharge gap is generated. A high voltage was applied to the medium voltage electrode by discharging.

Further, in this withstand voltage treatment method for a cathode ray tube, a high voltage resistor through which a discharge current of discharge generated in a discharge gap flows is provided between the medium voltage electrode and the low voltage electrode.

Further, the discharge gap for applying the high voltage pulse to the medium voltage electrode is used as the first discharge gap, and the second discharge gap is provided between the medium voltage electrode and the low voltage electrode. Furthermore, a withstand voltage treatment method for a cathode ray tube performed by applying a high voltage pulse to a high voltage electrode of an electron gun having at least a low voltage electrode, a medium voltage electrode and a high voltage electrode arranged in a neck of an envelope. In, in order to apply a high voltage to the high voltage electrode, a discharge gap is provided between the high voltage input terminal provided in the envelope and the medium voltage electrode, and the high voltage is applied to the medium voltage electrode by the discharge generated in this discharge gap. Was applied.

Furthermore, in this withstand voltage treatment method for a cathode ray tube, after the withstand voltage treatment between the high voltage electrode and the medium voltage electrode is completed, the discharge gap between the high voltage input terminal and the medium voltage electrode is formed. The discharge was made to occur.

Further, a high voltage of 60 kV or more is applied to the high voltage input terminal.

The discharge start voltage of the discharge gap is set to 30
It was set to -60 kV.

[0017]

With the above arrangement, a high voltage pulse can be applied not only between the electrodes on the high voltage side but also on the medium voltage electrode to generate discharge on the low voltage side, and sufficient withstand voltage treatment is performed. It becomes possible.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

FIG. 1 shows a circuit for explaining the withstand voltage processing method of the embodiment. Since the cathode ray tube itself has the same structure as that of the cathode ray tube shown in FIG. 3, the same portions are denoted by the same reference numerals and the description thereof will be omitted.

The electron gun of the illustrated cathode ray tube 10 includes a heater 11, a cathode 12, a first grid electrode 13, a second grid electrode 14, a third grid electrode 15, a fourth grid electrode 16, a fifth grid electrode 17, and a fifth grid electrode 17. 6 grid electrode 18
Have. The second grid electrode 14 and the fourth grid electrode 16, and the third grid electrode 15 and the fifth grid electrode 17 are respectively connected in the neck, a heater voltage is applied to the heater 11, and the first grid electrode 13 is The second grid electrode 14 and the fourth grid electrode 16 are grounded.
Has a low voltage, the third grid electrode 15 and the fifth grid electrode 17 have a medium voltage, and the sixth grid electrode 18 has a high voltage input terminal 20 provided on the funnel, and the interior provided on the inner surface of the funnel. An accelerating high voltage is applied via a conductive film or the like. That is, in this electron gun, the first grid electrode 13, the second grid electrode 14 and the fourth grid electrode 16 are the low voltage side electrodes, the third grid electrode 15 and the fifth grid electrode 17 are the medium voltage side electrodes, and the sixth
The grid electrode 18 constitutes the high-voltage side electrode as the final acceleration electrode.

In this embodiment, the output end of the power source 51 is connected to the high voltage input terminal 20 via the stabilizing resistor 52, and the other end is connected to the heater 1 via the stabilizing resistor 53 and the socket 30.
1, the cathode 12, the first grid electrode 13, the second grid electrode 14, and the fourth grid electrode 16 are connected. Further, outside the cathode ray tube 10, a discharge gap 50 is provided between the high voltage input terminal 20 and the third grid electrode 15 and the fifth grid electrode 17 which are intermediate voltage side electrodes. The intervals of the discharge gap 50 are set so that the discharge gap 50 is discharged at a discharge starting voltage of about 30 to 60 kV.
Further, outside the cathode ray tube 10, the third grid electrode 15 and the fifth grid electrode 17 which are the medium voltage side electrodes and the first grid electrode 13, the second grid electrode 14 and the fourth grid electrode 16 which are the low voltage side electrodes. A high-voltage resistor 54 is inserted between and.

With the above structure, when the output voltage of the power source 51 is set to 60 to 80 kV, discharge is generated between the high voltage side electrodes, and the withstand voltage between the sixth grid electrode 18 and the fifth grid electrode 17 adjacent thereto is increased. Voltage processing is performed. At this time, the third grid electrode 15 and the fifth grid electrode 17
Is applied with a high voltage pulse due to the voltage drop that occurs when the discharge current flows through the high voltage resistor 54, and this high voltage pulse causes discharge between the medium voltage side electrode and the low voltage side electrode,
Withstand voltage treatment between these electrodes is performed. That is, the withstand voltage process on the low voltage side is performed by utilizing the discharge current generated by the discharge between the high voltage side electrodes.

However, in the withstand voltage treatment on the low voltage side using the discharge current generated by the discharge between the high voltage side electrodes, when the discharge does not occur between the high voltage side electrodes, the high voltage is applied to the middle voltage side electrodes. Stops because it is no longer applied. However, in this case, when discharge does not occur between the high-voltage side electrodes, discharge is generated instead in the discharge gap 50, the discharge current flows through the high-voltage resistor 54, and a high-voltage pulse is applied to the middle-voltage side electrodes. . Then, by using the discharge current of the discharge gap 50, a high voltage pulse is continuously applied to the intermediate voltage side electrode, and after the high voltage side withstand voltage process is completed, the low voltage side withstand voltage process is performed. be able to.

In this withstand voltage processing method, since the voltage waveform applied from the power source 51 is a sharp pulse as shown by the broken line 42 in FIG. 7, a high voltage exceeding the critical voltage at which the creeping discharge occurs in the socket 30. Even when the voltage is applied, the applied voltage when the discharge current starts flowing becomes lower than the critical voltage, and the creeping discharge does not occur. Therefore, it is possible to increase the applied voltage and perform effective withstand voltage processing.
Moreover, even if the discharge does not occur between the electrodes on the high voltage side, the withstand voltage treatment can be performed by applying the pulse to the low voltage side electrode a sufficient number of times, and the withstand voltage treatment can be sufficiently performed.

Next, another embodiment will be described.

In the above-described embodiment, the high voltage necessary for the withstand voltage treatment on the low voltage side after the withstand voltage treatment on the high voltage side is completed is the discharge of the discharge generated in the discharge gap provided outside the cathode ray tube. The voltage drop that occurs when the current flows through the high-voltage resistance inserted between the medium-voltage side electrode and the low-voltage side electrode is used, but as shown in FIG. 2, the high-voltage input terminal 20 and the medium-voltage side electrode A discharge gap 5 provided outside the cathode ray tube between the third grid electrode 15 and the fifth grid electrode 17
0 as the first discharge gap, instead of the high voltage resistor of FIG. 1, the third grid electrode 15 and the fifth grid electrode 17
And a second discharge gap 55 between the first grid electrode 13, the second grid electrode 14 and the fourth grid electrode 16.
May be provided.

In this case, by setting the discharge starting voltage of the discharge gap 55 to 20 to 30 kV, a voltage with a small pulse width is applied to the low voltage side electrode as in the above embodiment, and the high voltage side withstand voltage is applied. Even after the voltage processing is completed, the withstand voltage processing on the low voltage side can be performed. When the discharge gap 55 is provided in this way, the number of pulses applied to the low voltage side electrode can be controlled by the interval of the discharge gap 55.

As a result of treating the cathode ray tube by each of the withstand voltage treatment methods described above, the conventional withstand voltage treatment method caused a shortage of withstand voltage treatment of about 10%, but this can be reduced to about 2%. It has been confirmed that the withstand voltage treatment can be performed efficiently and reliably.

It is needless to say that the discharge starting voltage of the discharge gap in the withstand voltage treatment of the present invention is not limited to the voltage shown in the above embodiment and may be set appropriately.

[0030]

As described above, according to the withstand voltage treatment method of the present invention, not only the withstand voltage treatment on the high voltage side but also the withstand voltage treatment on the low voltage side can be sufficiently performed. It is possible to eliminate the shortage of withstand voltage treatment, which was a problem of the voltage treatment method, and obtain a cathode ray tube with excellent withstand voltage characteristics.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a withstand voltage processing method according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a withstand voltage processing method according to another embodiment of the present invention.

FIG. 3 is a sectional view showing a configuration of a cathode ray tube.

FIG. 4 is a diagram for explaining a conventional withstand voltage processing method.

FIG. 5 is a diagram for explaining different conventional withstand voltage processing methods.

FIG. 6 is a diagram for explaining still another conventional withstand voltage processing method.

FIG. 7 is a diagram showing an applied waveform in a withstand voltage process.

[Description of Reference Signs] 10 ... Cathode ray tube 13 ... First grid electrode 14 ... Second grid electrode 15 ... Third grid electrode 16 ... Fourth grid electrode 17 ... Fifth grid electrode 18 ... Sixth grid electrode 20 ... High voltage input Terminal 30 ... Stem 50 ... Discharge gap (first discharge gap) 51 ... Power supply 54 ... High voltage resistance 55 ... Second discharge gap

Claims (7)

[Claims] 1. A cathode-ray tube withstand voltage treatment for causing withstand voltage treatment by causing discharge between electrodes of an electron gun having at least a low-voltage electrode, a medium-voltage electrode and a high-voltage electrode arranged in a neck of an envelope. In the voltage processing method, a discharge gap for applying a high voltage pulse to the intermediate voltage electrode is provided outside the cathode ray tube, and the high voltage pulse is applied to the intermediate voltage electrode by the discharge generated in the discharge gap. A withstand voltage treatment method for a cathode ray tube, comprising: 2. The withstand voltage treatment method for a cathode ray tube according to claim 1, wherein a high voltage resistor through which a discharge current of a discharge generated in a discharge gap flows is provided between the medium voltage electrode and the low voltage electrode. 3. A discharge gap for applying a high voltage pulse to the medium voltage electrode is used as a first discharge gap, and a second discharge gap is provided between the medium voltage electrode and the low voltage electrode. The withstand voltage treatment method for a cathode ray tube according to claim 1. 4. A cathode ray tube withstand voltage effected by applying a high voltage pulse to a high voltage electrode of an electron gun having at least a low voltage electrode, a medium voltage electrode and a high voltage electrode arranged in a neck of an envelope. In the voltage processing method, a discharge gap is provided between the high voltage input terminal provided in the envelope for applying a high voltage to the high voltage electrode and the medium voltage electrode, and the discharge generated in the discharge gap causes A withstand voltage processing method for a cathode ray tube, characterized in that the high voltage is applied to the medium voltage electrode. 5. A discharge is generated in a discharge gap between the high-voltage input terminal and the medium-voltage electrode after the withstand voltage treatment between the high-voltage electrode and the medium-voltage electrode is completed. The withstand voltage treatment method for a cathode ray tube according to claim 4. 6. The withstand voltage processing method for a cathode ray tube according to claim 5, wherein a high voltage of 60 kV or more is applied to the high voltage input terminal. 7. The discharge starting voltage of the discharge gap is 30 to 6
6. The withstand voltage processing method for a cathode ray tube according to claim 5, wherein the method is set to 0 kV.