JPH11224608A - High-voltage processing method for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-voltage processing method for a cathode-ray tube whereby a breakdown voltage is efficiently increased without causing a crack at the neck, a deterioration in electron radiation or the like. SOLUTION: A high-voltage processing method for a cathode-ray tube has an electron gun 24 to which a voltage lower than a high voltage from an anode terminal 26 is applied through a stem pin to an electrode and a cathode other than a high-voltage electrode to which the high voltage is applied, wherein an electrode other than the high-voltage electrode is grounded, a DC positive voltage which is 1.0 to 1.5 times the specified voltage applied between the high- voltage electrode and the ground upon driving the cathode-ray tube, and an AC voltage lower than the DC voltage is superimposed on the DC voltage and applied between the cathode and the ground.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage processing method for a cathode ray tube such as a color picture tube, and more particularly to a method for applying a high voltage from an anode terminal to an electrode other than a high voltage electrode and a cathode via a stem pin. The present invention relates to a high voltage processing method for a cathode ray tube that applies a voltage lower than a high voltage.

[0002]

2. Description of the Related Art A cathode ray tube such as a color picture tube has a vacuum envelope comprising a panel and a funnel-shaped funnel having a neck at one end, and an electron gun is arranged in the neck of the funnel. . The electron beam emitted from the electron gun is deflected by a deflecting device mounted on the outside of the funnel, and the phosphor screen formed on the inner surface of the panel is horizontally and vertically scanned to display an image. Is formed.

[0003] Generally, the electron gun has a cathode and a plurality of electrodes disposed in the direction of the phosphor screen from the cathode, and forms a final lens that ultimately accelerates the electron beam toward the phosphor screen. A high voltage is applied to the accelerating electrode via an anode terminal provided at the large diameter portion of the funnel, and an inner conductive film applied from the large diameter portion of the funnel to the inner surface of the adjacent portion of the neck. A voltage lower than the high voltage is applied to the cathode and the cathode via a stem pin (terminal) provided at the neck end.

In such a cathode ray tube, since the distance between the electrodes of the electron gun is generally small, the presence of projections or foreign matter such as burrs near the final accelerating electrode or this electrode causes an extremely high potential gradient, Discharge. For this reason, such a cathode ray tube is subjected to a high voltage treatment for increasing the withstand voltage after the exhaust is completed.

Conventionally, as a high voltage processing method, as shown in FIG. 5, both output terminals of a high voltage generating circuit 1 are short-circuited via a main discharge gap 2 and the output terminals are connected to an anode terminal of a cathode ray tube 3. 4 and the cathode terminal 5 for processing. However, in this processing method, a discharge is continuously generated in a portion having a low withstand voltage, a gas is discharged from the discharge portion by the Joule heat, a metal evaporated from the discharge portion is deposited on another portion, and furthermore, There is a problem that cracks easily occur in the neck 2 made of glass.

In order to solve such a problem, Japanese Patent Publication No. Sho 6
As shown in FIG. 6, a sub-discharge gap 8 is inserted into one output terminal of a high-voltage generating circuit 1 short-circuited via a main discharge gap 2 and the sub-discharge gap 8 is A method of connecting to the anode terminal 4 for processing is shown.

In Japanese Utility Model Publication No. 57-22684, as shown in FIG. 7, a rectifier 11 is provided at an output terminal of a power transformer 10 and a discharge gap 13 for generating a discharge by an AC power supply circuit 12 is interposed therebetween. A processing method is shown in which a discharge voltage generated in a direct current and a discharge voltage generated in an alternating current are superimposed and applied to an electrode of an electron gun.

[0008]

As described above, conventionally,
As a high voltage processing method for increasing the withstand voltage of a cathode ray tube, there is a method of short-circuiting both output terminals of a high voltage generating circuit through a main discharge gap and connecting the output terminals to an anode terminal and a cathode terminal. However, in this processing method, a discharge is continuously generated in a portion having a low withstand voltage, a gas is released from the discharge portion, a metal evaporated from the discharge portion is deposited on another portion, and furthermore, it is made of glass. There is a problem that cracks easily occur in the neck.

In order to solve such a problem, a sub-discharge gap is inserted at one output terminal of the high-voltage generating circuit short-circuited through the main discharge gap, and connected to an anode terminal via the sub-discharge gap. Or by interposing a rectifier and a discharge gap for generating discharge by an AC power supply circuit at the output end of a power transformer, and superimposing a discharge voltage generated in DC and a discharge voltage generated in AC on the electron gun. There is a processing method of applying a voltage to the electrodes.

However, even if the treatment is performed by such a method,
If a sufficient high voltage treatment is performed, dielectric breakdown occurs at the neck side end of the inner conductive film formed from the large diameter portion of the funnel to the inner surface of the adjacent portion of the neck, and the crack of the neck cannot be eliminated. . In addition, craters are generated on the cathode due to ion bombardment and the like, causing problems such as deterioration of electron emissivity.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a cathode-ray tube having a high voltage capable of sufficiently increasing a withstand voltage without causing cracks in a neck or deterioration of electron emissivity. The aim is to obtain a processing method.

[0012]

Means for Solving the Problems (1) Among a plurality of electrodes constituting an electron gun, electrodes other than a high voltage electrode to which a high voltage is applied from an anode terminal and a cathode are connected to the high voltage via a stem pin. In a high voltage processing method for a cathode ray tube to which a low voltage is applied, the electrodes other than the high voltage electrode are grounded, and the specified voltage applied to the high voltage electrode when driving the cathode ray tube between the high voltage electrode and the ground is 1.0 to 1.0. A 1.5-fold positive DC voltage was applied, and an AC voltage lower than the DC voltage was applied between the cathode and the ground while being superimposed on the DC voltage.

(2) In the high voltage processing method for a cathode ray tube of (1), the timing of applying a DC voltage and the timing of applying an AC voltage are shifted.

(3) In the high voltage processing method for a cathode ray tube of (2), an AC voltage is applied after a DC voltage is applied.

(4) Of the plurality of electrodes constituting the electron gun, a voltage lower than the high voltage is applied to the electrodes other than the high voltage electrode to which a high voltage is applied from the anode terminal and the cathode via the stem pin. In a high voltage processing method for a cathode ray tube, an electrode other than the high voltage electrode is grounded, an AC voltage is applied between the high voltage electrode and the ground, and a negative DC voltage is superimposed on the AC voltage between the cathode and the ground. Was applied.

(5) In the high voltage processing method for a cathode ray tube of (1) to (4), the application of the DC voltage and the AC voltage is repeatedly turned on / off.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a color picture tube as an example of a cathode ray tube for high voltage processing. This color picture tube is a panel 2
0 and a vacuum envelope comprising a funnel 22 having a funnel-like shape having a cylindrical neck 21 at one end thereof.
A phosphor screen 23 made of a three-color phosphor layer is provided on the inner surface of the light emitting device, and a shadow mask 24 is disposed inside the phosphor screen 23 so as to face the phosphor screen 23. On the other hand, the three electron beams 23B, 2B
An electron gun 24 for emitting 3G, 23R is provided.
An anode terminal 26 is provided on the large diameter portion 25 of the funnel 22. Further, an inner conductive film 27 is formed by application from the large diameter portion 25 of the funnel 22 to the inner surface of the adjacent portion of the neck 21. Reference numeral 28 denotes a deflecting device which is mounted outside the funnel 22 and deflects the three electron beams 23B, 23G, 23R emitted from the electron gun 24 horizontally and vertically.

The electron gun 24 is a QPF (Quadra).
Potential Focus) type electron gun,
As shown in FIG. 3, three cathodes K (only one is shown) arranged in a line in a direction perpendicular to the paper surface, and first cathodes K arranged in the direction of the phosphor screen sequentially from these cathodes K
To G6 to G6.

The second electrode G2 and the fourth electrode G4, and the third electrode G3 and the fifth electrode G5 are respectively connected in a tube. The sixth electrode G6 (final accelerating electrode) that forms the main lens that finally focuses the electron beam on the phosphor screen together with the fifth electrode G5 (focus electrode) is provided via the anode terminal and the inner conductive film. And 30
A high voltage of about 35 kV is applied to the other first to fifth electrodes G1 to G5 and the cathode K via stem pins 31 (terminals) provided on the stem 30 at the neck end. A predetermined voltage lower than the voltage is applied (see FIG. 2).

In order to increase the withstand voltage of such a color picture tube, in this embodiment, as shown in FIG.
One output terminals of the DC power supply 33 and the AC power supply 34 are connected to ground, and the first to fifth electrodes are connected to one output terminal via a stem pin to be grounded, and the other output terminal of the DC power supply 33 is connected to the other output terminal. Is connected to the sixth electrode via the anode terminal 26, and a positive DC voltage of 1.0 to 1.5 times the specified voltage applied to the sixth electrode when the color picture tube is driven between the sixth electrode and the ground is applied. While the voltage is repeatedly applied, the other output terminal of the AC power supply 34 is connected to the cathode via the cathode terminal, and an AC voltage lower than the DC voltage applied to the sixth electrode is superimposed on the DC voltage between the cathode and the ground. The voltage was applied repeatedly.

The AC voltage used in this case includes a pulse voltage (half-wave) due to charging and discharging of a capacitor, a pulse voltage (half-wave or full-wave) by an induction coil,
Any of a high frequency (about 400 kHz) shock pulse by a Tesler coil and a normal high frequency (about 500 kHz) may be used.

FIG. 4A shows a DC voltage 35 applied between the sixth electrode and the ground, and FIG. 4B shows an AC voltage 36 applied between the cathode and the ground via the cathode terminal. As shown in FIGS. 4A and 4B, the DC voltage 35 and the AC voltage 36 are shifted in application timing,
After a DC voltage 35 is applied between the sixth electrode and ground, an AC voltage 36 is applied between the cathode and ground with a slight delay.

Specifically, for example, a cycle of 10 seconds is applied, and a positive DC voltage 35 of 45 kV is applied between the sixth electrode and the ground at intervals of 2 seconds for 4 seconds. 0.5 to 2 seconds delayed, 15 kV AC voltage 36
Is applied between the cathode and ground.

As described above, the first to fifth electrodes are grounded, and the specified voltage 1.0 to 1.5 of the specified voltage applied when the color picture tube is driven is connected between the sixth electrode G6 to which the high voltage is applied and the ground. When a double positive DC voltage is applied and an AC voltage 36 is applied between the cathode K and the ground, when a high electric field is formed due to the application of the high DC voltage 35, a foreign substance such as dust causes blue glow. Occurs and discharge is likely to occur. In this state, the AC voltage 36 is superimposed and applied, and as a result, the withstand voltage can be increased at a low voltage. As a result, it is possible to prevent the dielectric breakdown of the neck at the end of the inner conductive film at the neck side and the deterioration of the electron emissivity of the cathode due to ion bombardment and the like, and it is possible to effectively perform a sufficient high voltage treatment.

In the above embodiment, a positive DC voltage is applied between the sixth electrode and the ground, and an AC voltage is applied between the cathode and the ground while being superimposed on the DC voltage. The first to fifth electrodes are grounded via stem pins, connected to the output terminal of an AC power supply at the anode terminal, and repeatedly applied with an AC voltage between the sixth electrode and ground, and connected to the output terminal of the DC power supply at the cathode terminal. Alternatively, a negative DC voltage may be superimposed on an AC voltage between the cathode and the ground and applied repeatedly.

In this case, the AC voltage applied between the sixth electrode and the ground and the DC voltage applied between the cathode and the ground need not have a specific relationship. The negative DC voltage applied between the sixth electrode and the ground is preferably about 35 to 60 kV.

Further, in the above-described embodiment, the high voltage processing of the color picture tube having the QPF type electron gun has been described, but the present invention relates to a BPF (Bi-Potential).
Focus electron gun and UPF (Uni-Potent)
The same effect can be obtained by applying the present invention to high voltage processing of a color picture tube having an electron gun other than the QPF type, such as an ial focus type electron gun. Similar effects can be obtained by applying the present invention to high voltage processing of a cathode ray tube other than a color picture tube.

[0029]

As described above, an electron gun in which a predetermined voltage lower than the above-mentioned high voltage is applied to each electrode other than the electrode to which a high voltage is applied via the anode terminal and the cathode via the stem pin, respectively. When a high voltage treatment is performed using a DC voltage and an AC voltage in combination for a cathode ray tube having the same, the withstand voltage can be increased at a low voltage, and the dielectric breakdown of the neck at the neck side end of the inner conductive film, which has occurred conventionally, and ion Deterioration of the electron emissivity of the cathode due to impact or the like can be prevented, and sufficient high-voltage processing can be performed effectively.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a high voltage processing method for a color picture tube according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of the color picture tube.

FIG. 3 is a diagram showing a configuration of an electron gun of the color picture tube.

FIGS. 4A and 4B are diagrams showing a relationship between a DC voltage and an AC voltage applied during the high voltage processing.

FIG. 5 is a view for explaining a conventional high voltage processing method for a cathode ray tube.

FIG. 6 is a diagram for explaining a conventional improved high voltage processing method.

FIG. 7 is a diagram illustrating a conventional improved different high-voltage processing method.

[Explanation of symbols]

 24 ... electron gun 26 ... anode terminal 31 ... stem pin G1 ... first electrode G2 ... second electrode G3 ... third electrode G4 ... fourth electrode G5 ... fifth electrode G6 ... sixth electrode K ... cathode

Claims (5)

[Claims] A voltage lower than the high voltage is applied to a cathode other than a high voltage electrode to which a high voltage is applied from an anode terminal and a cathode through a stem pin among a plurality of electrodes constituting an electron gun. In the high voltage processing method for a cathode ray tube, an electrode other than the high voltage electrode is grounded, and 1.0 to 1.5 times a specified voltage to be applied to the high voltage electrode when the cathode ray tube is driven between the high voltage electrode and the ground. A high-voltage processing method for a cathode-ray tube, wherein a positive DC voltage is applied and an AC voltage lower than the DC voltage is applied between the cathode and the ground so as to overlap the DC voltage. 2. The high voltage processing method for a cathode ray tube according to claim 1, wherein the timing of applying the DC voltage and the timing of applying the AC voltage are shifted. 3. The high voltage processing method for a cathode ray tube according to claim 2, wherein an AC voltage is applied after a DC voltage is applied. 4. A voltage lower than the high voltage is applied to the electrodes other than the high voltage electrode to which a high voltage is applied from the anode terminal and the cathode of the plurality of electrodes constituting the electron gun via a stem pin. In the high voltage processing method for a cathode ray tube, electrodes other than the high voltage electrode are grounded, an AC voltage is applied between the high voltage electrode and the ground, and a negative DC voltage is applied between the cathode and the ground to the AC voltage. A high voltage processing method for a cathode ray tube, characterized by superimposing and applying the voltage. 5. The high voltage processing method for a cathode ray tube according to claim 1, wherein the application of a DC voltage and an AC voltage is repeatedly turned on / off.