JPH0395834A - Withstand voltage treating method for cathode ray tube - Google Patents

Abstract

PURPOSE:To perform withstand voltage treatment of extremely high efficiency by applying positive pulse-like high voltage to an anode in the state that negative d.c. voltage is applied to one electrode, excluding the anode, among the electrodes which constitute an electron gun. CONSTITUTION:When a switch 17 is turned on, the first grid electrode G1 to the fifth grid electrode G5 are connected to a d.c. high-voltage power supply 16 and preset negative d.c. voltage is applied thereto, respectively. At this time, stray emission occurs in the vicinity of the opposite face of the electrode G5 to the sixth grid electrode G6. Also, stray emission occurs from the side face of the electrode G5 toward the inner wall of a neck portion 11. When a switch 21 is turned on in such a state and positive pulse-like high voltage is applied, electric discharge takes place between the electrode G6 and the electrode G5 and its current flows through an outside connection resistance 18, so that there is potential rise in the electrode G1, the second grid electrode G2 and the fourth grid electrode G4 to perform withstand voltage treatment between the electrode G5 and the electrode G4 and between the third grid electrode G3 and the electrode G2, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a withstand voltage treatment method performed in the final manufacturing process of a cathode ray tube to improve withstand voltage characteristics.

(Prior Art) Generally, in manufacturing a cathode ray tube, such as a color cathode ray tube, in the final process, a withstand voltage treatment called spot knocking is performed in order to improve the withstand voltage characteristics.

This withstand voltage processing method is to apply a 50% voltage to the anode of a color cathode ray tube that has completed evacuation, with all of the low potential electrode systems including the focusing electrode among the electrodes constituting the electron gun assembly being grounded. There is a processing method in which a pulsed high voltage equivalent to ~80 kV is repeatedly applied over several minutes to several tens of minutes. By performing this treatment, the microscopic protrusions that had adhered to the electrodes, as well as the electrode deposits caused by microscopic dust floating in the tube atmosphere, are fired or scattered.
This prevents discharge phenomena and changes in leakage current between the focusing electrode and anode during practical use.

In addition, as shown in Japanese Unexamined Patent Publication No. 63-241836, there is a method in which a high voltage is simultaneously applied to the anode and the focusing electrode in order to improve the withstand voltage characteristics of the low potential electrode system that constitutes the electron gun assembly. , as shown in Japanese Patent Application Laid-Open No. 54-74363, the anode of the electron gun assembly is set to ground potential, and a conductive metal cylinder is inserted around the outer periphery of the neck portion in which the electron gun assembly is housed. There is a method of intermittently applying a common negative high voltage to a metal cylinder and a socket to which stem pins for first, second, and fourth grid electrodes, which are a low potential electrode system, are collectively connected.

(Problem to be solved by the invention) However, these withstand voltage processing methods apply intermittent high voltage in the form of pulses, and even when DC high voltage is used together, the processing is short-term, so electronic integration is difficult. This results in voltage resistance treatment only between the electrodes that make up the structure.

Under actual usage conditions (continuous long-term use of several hours), not only the voltage resistance characteristics between the electrodes but also the voltage resistance characteristics between each electrode and the inner wall of the neck portion are important. In other words, when used continuously for a long time, the inner wall of the neck is charged up by the anode voltage over time, and the inner wall of the neck is charged up by the anode voltage. This is because withstand voltage failure symptoms such as stray emissions and discharge occur between the two. This means that when a completed color cathode ray tube is operated continuously for a long period of time, stray emissions may occur after several tens of minutes or hours have passed, or discharge may occur intermittently.

The above phenomenon will be explained in more detail below.

For example, when a color cathode ray tube having a six-pole electron gun structure is used, an anode voltage of about 25 to 30 kV is applied to the sixth grid electrode, which is the anode of the electron gun structure. Further, a focus voltage of about 28 to 3296 of the above-mentioned anode voltage is applied to the third and fifth grid electrodes, which are focusing electrodes, and a focus voltage of about 500
A screen voltage of about ~800v is applied, and
The first grid electrode is used in a grounded state.

Here, the electric potential of the inner wall of the neck portion in which the electron gun structure having the above configuration is housed is in a state close to zero until each of the above operating voltages is applied. (minutes to several hours), the battery is charged up and the potential increases.

That is, the potential difference between the side surface of each electrode and the inner wall of the neck portion increases. Therefore, if there are minute deposits or the like between them, stray emissions or discharge will occur due to the potential difference.

In the above-described withstand voltage processing method in which a pulsed high voltage is applied to the anode with the electrodes other than the anode grounded, the processing between the sixth grid electrode, which is the anode, and the fifth grid electrode, which is the focus electrode, is It is difficult to generate a potential difference between the other electrode side surfaces and the inner wall of the neck portion, and no withstand voltage treatment is performed between them. For this reason, during use, voltage withstand defects such as stray emissions occur as described above.

In the other conventional examples as well, no consideration has been given to voltage resistance characteristics between the inner wall of the neck portion and the side surfaces of each electrode due to long-term use, and the voltage resistance characteristics are not sufficiently ensured.

An object of the present invention is to provide a cathode ray tube that has high withstand voltage characteristics by efficiently and easily treating not only the space between each electrode, but also the space between the inner wall of the neck part and the side surface of each electrode, which becomes a problem when used for a long time. An object of the present invention is to provide a method for treating cathode ray tubes with withstand voltage, which can obtain the following characteristics.

[Structure of the invention]

(Means for Solving the Problems) A withstand voltage treatment method for a cathode ray tube according to the present invention includes applying a negative DC voltage to at least one electrode other than the anode among the electrodes constituting the electron gun assembly. A pulsed positive high voltage is applied to the anode.

(Function) In the present invention, by applying a negative DC voltage to electrodes other than the anode, that is, a DC voltage equivalent to a DC voltage with a degree of force slightly higher than the actual usage conditions, stray emissions are continuously generated between the electrodes and the anode. can be generated. Also,
Under normal use, the inner wall of the neck will rise toward the anode voltage over time, but by applying a negative DC voltage, a forced potential difference can be maintained from that point on.

In this way, a potential difference is created between the electrodes under conditions equivalent to charging up the neck part under normal usage conditions, and while stray emissions are continuously generated, a processing voltage, that is, a positive By applying a pulsed high voltage of 1, this processing voltage is applied to the portions requiring withstand voltage treatment, and extremely efficient withstand voltage treatment can be performed. As a result, a cathode ray tube can be obtained that has highly reliable withstand voltage characteristics that can withstand long-term use.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, 11 is a neck portion of a glass bulb for a cathode ray tube, and an electron gun assembly 12 is housed inside the neck portion. As is well known, this electron gun structure 12 has a first grid electrode G.
1. A second grid electrode G2, a third grid electrode G3 as a focusing electrode, a fourth grid electrode G4, and a fifth grid electrode also as a focusing electrode.
It consists of a grid electrode G5 and a sixth grid electrode G6 serving as an anode, and these grid electrodes 61 to G6 are held at a constant distance from each other by bead glass (not shown). Furthermore, the third grid electrode G3 and the fifth grid electrode G5 are commonly connected by a connector 13, and the second grid electrode G2 and the fourth grid electrode 64 are commonly connected by a connector 14. There is.

Next, a withstand voltage processing apparatus for performing withstand voltage processing on the inside of the neck portion 11 of the cathode ray tube constructed as described above and between each electrode of the electron gun assembly 12 will be described.

16 is a DC high voltage power supply, the positive side of which is grounded, and the negative side connected to the first grid electrode G1 after passing through a switch 17;
A third grid is connected to a second grid electrode G2 and a fourth grid electrode G4 which are internally connected to each other by a connector 14, and is also internally connected by a connector 13 as a focusing electrode after passing through an external connection resistor l8. Electrode G
3 and the fifth grid electrode G5, respectively. Therefore, by turning on the switch 17, each of these electrodes Gl, G2, G3 . A negative DC voltage is applied to G4 and G5.

20 is a high-voltage pulse power supply, one end of which is grounded, and the other end is connected to the sixth grid electrode G6, which is an anode, through a switch 2l and an anode button provided in the funnel (not shown) of the glass bulb. When the switch 21 is turned on, a positive pulsed high voltage is applied to the anode G6.

Here, the DC high voltage power supply 16 is set to generate a negative voltage equivalent to 1.2 to 1.5 times the anode voltage in actual use, for example, -35 kV. In addition, the positive high voltage pulse power supply 20 is 3 to 101{z (, for example, 5H
z) It is set to generate a pulse-like high voltage of 30 to 50 kV (for example, 35 kV).

In such a configuration, when the switch 17 is turned on, the first grid electrode 61 to the fifth grid electrode G5 are connected to the DC high voltage power supply l6, and a predetermined negative DC voltage is applied to each of them. Then, the sixth grid electrode G6 and the fifth grid electrode G
5, a potential difference occurs due to the voltage supplied from the DC high voltage power supply 16. Furthermore, the inner wall of the neck opening is in a nearly uncharged state before the switch I7 is turned on, but when the switch 17 is turned on, a negative charge is applied to the inner wall of the neck opening by the first grid electrode 01 to the fifth grid electrode G5. , and a potential difference is generated between each electrode side surface.

This means that we have created a condition that is almost equivalent to operating a color cathode ray tube for a long time with an appropriate degree of force. At this point, voltage resistance treatment is not performed or is insufficient, so stray emissions occur from near the surface of the fifth grid electrode G5 facing the sixth grid electrode G6.

In addition, stray emissions occur from the side surface of the fifth grid electrode G5 toward the inner wall of the neck portion 11 (or under the influence).

With stray emissions appearing in this way, turn on the switch 21 and apply a positive pulsed high voltage (processing voltage).
When applied, a discharge occurs at the location where the stray emissions are occurring, and stray emission sources such as electrode deposits can be efficiently burnt out or scattered.

When a discharge occurs from the sixth lattice electrode G6 to the fifth lattice electrode G5 due to the above-described withstand voltage treatment, the discharge current flows to the externally connected resistor l8, and the discharge current flows to the first lattice electrode G1, the second lattice electrode G2, and the fourth lattice electrode G5. The potential is increased with respect to G4, and the fifth grid electrode G5 and the fourth grid electrode G4, the third grid electrode G3 and the second grid electrode
A withstand voltage treatment is applied between the grid electrode G2 and the grid electrode G2. For the externally connected resistor 18, a resistor of approximately InkΩ is used.

In this way, by applying a negative DC high voltage to the electrodes other than the sixth lattice electrode G6 as an anode, the inner wall of the neck portion 11 due to charge-up of the anode voltage, which can be a problem with long-term mounting during actual use. The occurrence of stray emissions and discharge symptoms can be set extremely easily, and by applying a positive pulse-like high voltage, which is the processing voltage, to the anode in this state, the necessary parts can be instantly and efficiently set. Can be treated with voltage resistance. Therefore, a color cathode ray tube can be obtained that has highly reliable withstand voltage characteristics that can withstand long-term use.

Note that the above-mentioned withstand voltage treatment method is effective even when applied to a part of the conventional withstand voltage treatment process, but by introducing it to the majority of the process, the withstand voltage treatment time can be significantly shortened to about 1/3. I can do it.

Next, the embodiment shown in FIG. 2 will be explained. In this embodiment, the DC high voltage power supply 16 includes a power supply +6A whose output voltage is set to 35 kV (hereinafter referred to as -35 kV power supply), and a power supply 16B whose output voltage is set to the same <-12 kV (hereinafter referred to as 12 kV power supply). Power supply set to the same <-23kV (
(hereinafter referred to as -23kV power supply) 16C is provided for the tail. −
The 35kV power supply 16^ and the -+2kV power supply 16B are connected to the first grid electrode Gl, the second grid electrode G2, and the fourth grid electrode G4, which are internally connected by the connector 14, after passing through the changeover switch 17 and the normally-on switch 23. Connect to. Therefore, these electrodes Gl, G2,
-35 is set to G4 by the switching operation of the selector switch 17.
Either kV or -+2kV can be selectively applied. Further, the -23 kV power supply 16C is connected to the third grid electrode 63d and the fifth grid electrode G5, which are internally connected by the connector 13, through the normally-on switch 24. Therefore, these electrodes G3,
-23 kV is applied to G5 when the normally-on switch 24 is in the on state.

The high-voltage pulse power source 20 is connected to the sixth grid electrode G6, which is an anode, through a switch 21, as in the embodiment shown in FIG.

In the above configuration, when performing voltage resistance processing, first, switch 17 is set to the -35kV power supply 16^ side, and
Switches 21 are respectively switched to the high voltage pulse power supply 2o side. In this state, 35 kV is applied to the electrodes Gl, G2 and G4, and the voltage of 35 kV is applied to the electrodes G3 and G5. -23kV i)<
Furthermore, a positive pulsed high voltage (for example, +35 kV) is periodically applied to the electrode G6.

That is, when +35kY is applied to the electrode G6, the electrode G
The potential difference between 6 and 65 becomes extremely large, 7QkV, and withstand voltage treatment (spot knocking) is performed during this time.

In addition, since the inner wall of the neck portion l1 is negatively charged, when the positive pulse-like high voltage is applied, the potential difference therebetween also increases. Withstand voltage treatment is also performed at the same time.

Next, after turning off the normally-on switch 23, the switch 17 is switched to the -12 kV power supply 16B side, and the normally-on switch 23 is turned on again. Due to this switching, the voltage applied to electrodes G3 and G5 is -12k.
Changes to V. That is, electrodes G3, G5 and electrode G2
, G4, the voltage direction is reversed, and the potential difference is 11
kV, and voltage resistance treatment between these electrodes is performed.

In the illustrated example, the switch 2l is switched to the high voltage pulse power supply 20 side from the beginning, but it may be switched to the ground side at first. In this case, the switch 21 may be switched to the high voltage pulse power source 20 side after a certain amount of time has passed.

Next, the embodiment shown in FIG. 3 will be explained. In this example, the second
As shown in the figure, three DC power supplies 1 are used as the DC high voltage power supply 16.
6^, 168. It has 16C, but one of them is 16
c is configured so that the output voltage can be varied within the range of -23 kV to -35 kV. In addition, high voltage pulse power supply 20
The voltage and frequency of the first pulsed power source 20^ were set to be similar to those shown in Figures 1 and 2, and both the voltage and frequency were set to about half of the first pulsed power source 20^ described above. A second pulse power source 20B is provided.

The DC power supplies, that is, the -35kV power supply 16A and the -12kV power supply 16B, are connected to the changeover switch 17 and the normally-on switch 23, as in FIG.
It is connected to a first grid electrode Gl, and a second grid electrode G2 and a fourth grid electrode G4 which are internally connected by a connector 14. Further, the variable power supply l6C is connected to the third grid electrode G3 and the fifth grid electrode G5, which are internally connected by the connector 13, through one switching side of the changeover switch 26 and the normally-on switch 24. . 1st
The pulse power source 20A is connected to the sixth grid electrode G6, which is an anode, through one switching side of the changeover switch 27 and the switch 21. Furthermore, a second pulse power source 2
0B is connected to the other switching side of each of the changeover switches 26 and 27.

In the above configuration, when carrying out withstand voltage processing, first, switch 17 is set to the -35kV power supply l6^ side, and
Switch 26 to the variable power supply 16c side, switch 2127
are respectively switched to the first pulse power supply 2OA side. In this state, the electrodes Gl, G2 . -35kV is applied to G4, and electrodes G3, G5+,: -23kV to -35
kV (7) A variable voltage is applied, and the electrode G
6 is periodically applied with a positive pulsed high voltage (for example, +35 kY).

Here, when the voltage applied to the electrodes G3 and G5 is adjusted to -23 kY, withstand voltage processing is performed due to the potential difference between the electrodes G2 and G4 and G3 and G5. Further, when the applied voltage is gradually adjusted from -23kV to -35kY, the potential difference between each electrode G2 and G4 gradually changes, and a positive pulse-like high voltage (for example, +35kV) is applied to the electrode G6.
is applied, the potential difference between electrodes G6 and 65 is 7
The optimum value is 0 kV, and withstand voltage processing during this period can be effectively performed. Of course, the voltage resistance treatment between the neck portion 11 and the inner wall is performed in the same manner as in the previous embodiment.

After the above-mentioned withstand voltage treatment, the switch 17-1 is further
Switch the 2kV power supply 16B to the second pulse power supply 21B, and switch the electrodes G3, G5 and G2 to the second pulse power supply 21B.
, G4, the withstand voltage processing becomes even more reliable.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to efficiently and easily apply voltage resistance treatment not only between each electrode, but also between the inner wall of the neck part and the side surface of each electrode, which becomes a problem when used for a long time. A highly reliable cathode ray tube with high withstand voltage characteristics can be obtained.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the configuration of a withstand voltage processing apparatus used in an embodiment of the withstand voltage processing method for cathode ray tubes according to the present invention;
Both FIG. 3 and FIG. 3 are circuit diagrams showing a configuration example of a withstand voltage processing apparatus used in another embodiment of the present invention. DESCRIPTION OF SYMBOLS 11... Neck part, 12... Electron gun structure, l6... DC high-voltage power supply that generates a negative DC voltage, 20... High-voltage pulse power supply that generates a positive pulse-like high voltage, Gl, G2, (;3,
G4, G5... Electrodes other than an anode, G6... Electrodes as an anode. )1l'

Claims (1)

[Claims] (1) A pulsed positive high voltage is applied to the anode while a negative DC voltage is applied to at least one electrode other than the anode among the electrodes constituting the electron gun structure. Voltage resistance treatment method for cathode ray tubes.