JPH05258670A - Manufacture of cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent a neck through breakage generated at the time of withstand voltage treatment. CONSTITUTION:Before an electron gun is sealed in the neck part of a bulb having a conductive film 7 formed from the major diameter part inner surface of a funnel 2 to a neck 5 inner surface adjacent to the major diameter part, the conductive film being connected to an anode terminal 8 provided on the major diameter part of the funnel 2, or before the funnel 2 is connected to a panel, an inert gas, air or a mixed gas thereof is charged in the bulb or the funnel 2. An electrode 21 is arranged in the neck, a voltage for regularly or periodically making the anode terminal 8 negative is applied between the electrode 21 and the anode terminal 8 to generate a discharge between the electrode 21 and the end part of the conductive film 7 formed on the neck inner surface, and the vicinity of the end part of the conductive film 7 on the neck inner surface is electrically smoothed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cathode ray tube such as a color picture tube and, more particularly, to a method for manufacturing a cathode ray tube in which neck penetrating breakdown caused by discharge during withstand voltage treatment is prevented.

[0002]

2. Description of the Related Art Generally, a cathode ray tube is constructed as shown in FIG.
It has a bulb 3 made up of a glass panel 1 (also called face plate) and a glass funnel-shaped funnel 2 (also called cone portion), and a phosphor screen 4 is formed on the inner surface of the panel 1. On the other hand, the electron gun 6 including a plurality of electrodes is sealed in the neck 5 of the funnel 2. An inner conductive film 7 containing graphite as a main component is provided on the inner surface of the large-diameter portion of the funnel 2 and the inner surface of the neck 5 adjacent to the large-diameter portion of the funnel 2. The structure is such that a high voltage supplied to the anode terminal 8 provided in the large-diameter portion is applied to the phosphor screen 4 and the final acceleration electrode of the electron gun 6.

Particularly in a color picture tube, the phosphor screen 4 is composed of a three-color phosphor layer, and the phosphor screen 4 is opposed to the phosphor screen 4 and emitted from the electron gun 6 inside.
A shadow mask 10 is arranged as a color selection electrode for selecting an electron beam, and a high voltage supplied to an anode terminal 8 provided in a large-diameter portion of the funnel 2 is supplied to the shadow mask 10 and the shadow mask 10 to cause fluorescence. The structure is such that it is applied to the body screen 4 and is applied to the final accelerating electrode of the electron gun 6.

In FIG. 5, 11 is a deflection yoke, and the electron beam emitted from the electron gun 6 is deflected by the magnetic field generated by the deflection yoke 11 to scan the phosphor screen 4 horizontally and vertically. To display the image.

Conventionally, the cathode ray tube is manufactured as follows.

For a color picture tube, for example, as shown in FIG. 6, a phosphor screen is formed on the inner surface of the panel, and a shadow mask is attached to the inside of the panel on which the phosphor screen is formed. On the other hand, conductive paint is applied to the inner surface of the funnel to form the inner conductive film. Then, the panel on which the shadow mask is mounted and the funnel on which the inner surface conductive film is formed are integrally sealed (bonded) with frit glass. Next, the pre-assembled electron gun is sealed in the neck of the bulb composed of the panel and the funnel formed by this sealing. Next, the sealed valve of this electron gun is evacuated. After that, a reinforcing band or the like is attached to the outer surface of the panel of the exhausted valve to carry out an explosion-proof treatment, and then it is manufactured by subjecting it to aging, withstand voltage treatment and the like.

However, when the cathode ray tube is manufactured by the above method, an electric field is concentrated near the end portion of the inner conductive film formed by coating on the inner surface of the neck during the withstand voltage treatment, and a breakdown that penetrates the neck occurs due to discharge. Sometimes. In particular, this neck penetration failure is likely to occur at high humidity.

Therefore, in the conventional withstand voltage treatment, measures such as removing stains on the outer surface of the neck, drying with hot air, lowering the withstand voltage treatment voltage, and shortening the application time have been taken.

[0009]

As described above, in the manufacture of the cathode ray tube, as described for the color picture tube, after sealing the panel and the funnel having the inner surface conductive film applied thereon, the panel and the funnel are sealed. It is manufactured by sealing an electron gun in the neck of a valve composed of a funnel, exhausting it, subjecting it to explosion-proof treatment, and then subjecting it to aging, withstand voltage treatment and the like. However, when a cathode ray tube is manufactured by this method, an electric field may be concentrated in the vicinity of the end of the inner conductive film formed by coating on the inner surface of the neck during the withstand voltage treatment, and electric discharge may cause destruction through the neck. In particular, this neck penetration failure is likely to occur at high humidity.

Therefore, in the conventional withstand voltage treatment, measures such as removing stains on the outer surface of the neck, drying with hot air, lowering the withstand voltage treatment voltage, and shortening its application time have been taken. However, the removal of dirt on the outer surface of the neck and the drying by hot air are limited as a countermeasure against the break-through of the neck, and the break-through of the neck cannot be sufficiently prevented. Therefore, the frequency of the withstand voltage treatment is often reduced by lowering the voltage or shortening the application time. However, if the voltage of the withstand voltage process is lowered or the application time is shortened, the withstand voltage process of the cathode ray tube tends to be insufficient, and the withstand voltage characteristic is deteriorated.

The present invention has been made in order to solve the above-mentioned problems, and a cathode ray tube capable of improving the withstand voltage characteristic without causing neck penetrating breakdown during withstand voltage treatment of the cathode ray tube. The purpose is to obtain a manufacturing method.

[0012]

In a method of manufacturing a cathode ray tube, a conductive film is formed from an inner surface of a funnel-shaped funnel having a large diameter portion to an inner surface of a neck adjacent to the large diameter portion, and the conductive film has a large funnel diameter. Before sealing the electron gun in the neck of the valve connected to the anode terminal provided in the section, fill the valve with inert gas or air or a mixed gas of inert gas and air, and An electrode is arranged on the electrode, and a voltage that makes the anode terminal negative at all times or periodically is applied between the electrode and the anode terminal to generate a discharge between the electrode and the end of the conductive film formed on the inner surface of the neck. Raise,
The vicinity of the end of the conductive film formed on the inner surface of the neck was electrically smoothed.

Further, a funnel-shaped funnel formed by forming a conductive film from the inner surface of the large-diameter portion to the inner surface of the neck adjacent to the large-diameter portion and connecting the conductive film to an anode terminal provided in the large-diameter portion is used as a panel. Before joining to, the funnel is filled with an inert gas or air or a mixed gas of an inert gas and air, and an electrode is arranged in the neck, and an anode terminal is always or between the electrode and the anode terminal. A negative voltage is applied periodically to generate a discharge between the electrode and the end of the conductive film formed on the inner surface of the neck, and the vicinity of the end of the conductive film formed on the inner surface of the neck is electrically smoothed. I tried to turn it on.

[0014]

As described above, the valve or funnel is filled with an inert gas or air or a mixed gas of an inert gas and air, and an electrode is arranged in the neck of the valve or funnel, and between the electrode and the anode terminal. A voltage applied to the anode terminal constantly or periodically causes a discharge to occur between the electrode and the end of the conductive film formed on the inner surface of the neck, and the conductive film on the inner surface of the neck is generated during withstand voltage treatment. It is possible to electrically smooth an electric field concentrated portion near the end portion of the, and prevent neck penetrating breakdown during withstand voltage treatment.

[0015]

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

(Embodiment 1) FIG. 2 shows a method of manufacturing a color picture tube according to the first embodiment. This color picture tube is manufactured by assembling a panel / mask assembly in which a shadow mask is detachably attached to a panel,
With respect to the mask assembly, a phosphor screen made of a three-color phosphor layer that emits blue, green, and red is formed on the inner surface of the panel by a photo printing method. On the other hand, from the inner surface of the large-diameter portion of the funnel to the inner surface of the portion adjacent to the large-diameter portion of the neck, a conductive coating material containing graphite as a main component is applied to form an inner conductive film. The inner conductive film is connected to the anode terminal provided on the large diameter portion of the funnel. Further, frit glass is applied to the large-diameter end surface (sealing surface) of the funnel on which the inner conductive film is formed. Then, a shadow mask is mounted on the panel on which the phosphor screen is formed, the panel on which the shadow mask is mounted is aligned with the funnel coated with the frit glass, heated, and sealed by the frit glass.

Next, regarding the valve composed of the panel and the funnel sealed with the frit glass,
Performs neck penetration breakage prevention processing. This treatment for preventing penetration through the neck is performed by filling the inside of the valve with an inert gas or air or a mixed gas of an inert gas and air, and as shown in FIG. 1, an inner conductive film formed on the inner surface of the neck 5 by coating.
Insert the electrode 21 into the end hole 20 side of the neck 5 rather than the end of 7, and between the electrode 21 and the anode terminal 8 provided in the large diameter part of the funnel 2, the anode terminal 8 side is negative. High voltage is applied for a certain period of time, and the conductive film 7 and electrode 21 on the inner surface of the neck 5 are
It is carried out by generating a glow discharge or a spark discharge between and. In FIG. 1, reference numeral 22 is a discharge current suppressing resistor.

Next, as shown in FIG. 2, a preassembled electron gun is sealed in the neck of the valve which has been subjected to the above-described neck penetration breakage prevention treatment. Then, the sealed valve of the electron gun is evacuated, and the getter enclosed in the valve is flushed together with the electron gun to increase the vacuum degree in the tube, and then the explosion-proof treatment is performed. After that, aging and withstand voltage treatment are performed.

By the way, the end portion of the inner conductive film 7 applied to the inner surface of the neck 5 is sealed before the panel and the funnel are sealed and the electron gun is sealed in the valve composed of the panel and the funnel as described above. Insert the electrode 21 into the end opening 20 side of the neck 5 and apply a high voltage between the electrode 21 and the anode terminal 8 so that the anode terminal 8 side becomes negative, and the conductive film 7 on the inner surface of the neck 5 is applied. When a glow discharge or a spark discharge is generated between the electrode 21 and the electrode 21, the electric field concentrated portion near the end of the conductive film 7 on the inner surface of the neck 6 can be electrically smoothed by the discharge, and the conventional withstand voltage can be increased. It is possible to extremely reduce the break-through of the neck that occurs during processing. Further, since the penetration through the neck is prevented, the applied voltage at the time of the withstand voltage treatment can be increased, whereby a color picture tube having an excellent withstand voltage characteristic can be obtained.

(Embodiment 2) FIG. 3 shows a method of manufacturing a color picture tube according to a second embodiment. This color cathode ray tube manufacturing method is similar to the first embodiment in that a panel / mask assembly in which a shadow mask is removably attached to a panel is photographic-printed with blue on the inner surface of the panel.
A phosphor screen including a three-color phosphor layer that emits green and red light is formed. On the other hand, a conductive paint containing graphite as a main component is applied from the inner surface of the large-diameter portion of the funnel to the inner surface of the neck to form an inner conductive film connected to the anode terminal provided in the large-diameter portion. Then, a neck penetration breakage prevention process is performed on the funnel formed by applying the conductive paint.

That is, the funnel is filled with an inert gas or air or a mixed gas of an inert gas and air, and as shown in FIG. 4, the inner conductive film 7 is formed by coating on the inner surface of the neck 5 of the funnel 2. Insert the electrode 21 into the end opening 20 side of the neck 5 rather than the end of the, and the anode terminal 8 side becomes negative between this electrode 21 and the anode terminal 8 provided in the large diameter part of the funnel 2. Apply high voltage for a certain period of time to
5 Glow discharge or spark discharge is generated between the inner conductive film 7 and the electrode 21.

After that, frit glass is applied to the end surface of the large-diameter portion of the funnel which has been subjected to the above-described neck penetration breakage prevention treatment. Then, a shadow mask is mounted on the panel on which the phosphor screen is formed, the panel on which the shadow mask is mounted is aligned with the funnel coated with the frit glass, heated, and sealed by the frit glass.

After that, as shown in FIG. 3, a preassembled electron gun is sealed in the neck of the bulb composed of the panel and the funnel sealed with the frit glass. Then, the sealed valve of the electron gun is evacuated, and the getter enclosed in the valve is flushed together with the electron gun to increase the vacuum degree in the tube, and then the explosion-proof treatment is performed. After that, aging and withstand voltage treatment are performed.

After the inner surface conductive film 7 is applied and formed on the inner surface of the funnel 2 as in this embodiment, before the funnel 2 is sealed to the panel, an inert gas, air, or an inert gas is introduced into the funnel 2. When the neck penetration destruction prevention treatment is performed by filling a mixed gas of air and air, the electric field concentrated portion near the end of the conductive film 7 on the inner surface of the neck 5 can be electrically smoothed as in the first embodiment. It is possible to extremely reduce the neck penetration breakage that has conventionally occurred during the withstand voltage treatment. Further, since the penetration through the neck is prevented, the applied voltage at the time of the withstand voltage treatment can be increased, whereby a color picture tube having an excellent withstand voltage characteristic can be obtained.

(Embodiment 3) In each of the above-mentioned embodiments, a high voltage, which is always negative on the anode terminal side, is applied between the electrode inserted on the end opening side of the neck and the anode terminal to break through the neck. Although the prevention process was performed, the voltage applied between this electrode and the anode terminal may be a high voltage at which the anode terminal is periodically negative.

Although each of the above embodiments has been described with respect to the manufacture of a color picture tube, the present invention can be applied to the manufacture of cathode ray tubes other than the color picture tube.

[0027]

The cathode ray tube valve or funnel is filled with an inert gas or air or a mixed gas of an inert gas and air, and an electrode is arranged in the neck of the cathode ray tube valve or the funnel. When a voltage is applied to the terminal constantly or periodically to prevent it from breaking through the neck, a discharge is generated between the electrode and the end of the conductive film formed on the inner surface of the neck. It is possible to electrically smooth the electric field concentrated portion generated in the vicinity of the end portion of the conductive film formed on the substrate, and prevent neck penetrating breakdown that occurs during withstand voltage treatment. Further, since the penetration through the neck is prevented, the applied voltage at the time of withstanding voltage treatment can be increased, whereby a cathode ray tube with excellent withstanding voltage characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a neck penetration breakage preventing process in a method of manufacturing a color picture tube which is a first embodiment of the present invention.

FIG. 2 is a flow chart for explaining a method of manufacturing a color picture tube that is the first embodiment of the present invention.

FIG. 3 is a flow chart for explaining a method of manufacturing a color picture tube which is a second embodiment of the present invention.

FIG. 4 is a diagram for explaining a neck penetration breakage prevention process in the method of manufacturing a color picture tube according to the second embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a color picture tube.

FIG. 6 is a flowchart for explaining a conventional method of manufacturing a color picture tube.

[Explanation of symbols]

 2… Funnel 5… Neck 7… Inner conductive film 8… Anode terminal 21… Electrode

Claims (2)

[Claims] 1. A conductive film is formed from the inner surface of the large-diameter portion of the funnel-shaped funnel to the inner surface of the neck adjacent to the large-diameter portion, and the conductive film is connected to an anode terminal provided in the large-diameter portion of the funnel. Before sealing the electron gun in the neck of the valve, the valve is filled with an inert gas or air or a mixed gas of an inert gas and air, and an electrode is arranged in the neck. And a voltage that makes the anode terminal negative at all times or periodically is applied between the anode terminal and the anode terminal to generate a discharge between the electrode and the end portion of the conductive film formed on the inner surface of the neck, and A method of manufacturing a cathode ray tube, characterized in that the vicinity of an end of a conductive film formed on the inner surface of the neck is electrically smoothed. 2. A funnel-shaped funnel formed by forming a conductive film from an inner surface of the large-diameter portion to an inner surface of the neck adjacent to the large-diameter portion and connecting the conductive film to an anode terminal provided in the large-diameter portion. Before joining to the panel, the funnel is filled with an inert gas or air or a mixed gas of an inert gas and air, and an electrode is arranged in the neck, and the electrode is placed between the electrode and the anode terminal. A voltage is applied to the anode terminal to make it negative either constantly or periodically to generate a discharge between the electrode and the end of the conductive film formed on the inner surface of the neck, so that the conductive film formed on the inner surface of the neck is discharged. A method of manufacturing a cathode ray tube, which comprises electrically smoothing the vicinity of an end portion.