JP3254711B2 - Picture tube manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image receiving apparatus which is capable of efficiently discharging foreign matter which remains in a glass bulb having a phosphor film and a metal back on the inner surface of a front wall. The present invention relates to a method for manufacturing a pipe.

[0002]

2. Description of the Related Art If a minute conductive foreign substance undesirably remains in a glass bulb having a phosphor film and a metal back provided on the inner surface of a front wall, there is a danger of causing a spark in a tube or a short circuit between electrodes. In addition, stray emissions are likely to occur. Therefore, at the stage before the electron gun is inserted into the glass bulb, it is common practice to flow a gas such as air or nitrogen into the glass bulb while giving a mechanical impact to the glass bulb.

[0003]

However, in many cases, the foreign matter is electrostatically attached to the inner surface of the glass bulb by electrification, and does not fall off even when subjected to a mechanical shock, so that the foreign matter is a so-called foreign matter in the tube. Easy to survive. In particular, in a picture tube used for a projection type TV, the anode voltage is set higher than that of a general color picture tube in order to obtain a particularly large light output. For this reason, reliability in high-voltage operation is particularly demanded, and the presence of foreign matter in the pipe that causes sparks or stray emissions in the pipe is not allowed.

[0004]

According to the present invention, a glass bulb having a phosphor film and a metal back provided on an inner surface of a front wall is projected from an opening of a gas inlet tube.
And applying a predetermined high voltage to the discharge needle and grounding the anode button terminal connected to the metal back while applying a mechanical shock to the glass bulb, thereby grounding the inside of the glass bulb. The gas introduced into is ionized.

[0005]

With this configuration, a positive or negative charge is given to the foreign matter that has remained unintentionally in the glass bulb, so that the foreign matter is neutralized and receives a mechanical shock. The foreign matter easily falls off and is discharged out of the glass bulb together with the gas introduced into the glass bulb.

[0006]

Next, the present invention will be described with reference to the illustrated embodiment. A glass bulb 1 shown in FIG. 1 is for a picture tube provided for a projection type TV, and has a phosphor film 2 and an aluminum vapor-deposited film 3 as a metal back on an inner surface of a front wall thereof.
Is attached. These have been baked, and the aluminum vapor-deposited film 3 is electrically connected to the anode button terminal 4. The button terminal 4 is grounded. A vibrator 5 for applying a mechanical impact to the glass bulb 1 is connected to a front wall of the glass bulb 1. Reference numeral 6 denotes an aquaduck layer.

In the glass bulb 1, a gas introduction tube 8 for introducing a gas 7 such as air or nitrogen and a discharge needle 9 are provided.
Are inserted, and the discharge needle 9 is connected to a high-voltage generating power supply 10. Reference numeral 11 denotes an insulating layer for the discharge needle 9. The vibrator 5 acts to apply a mechanical shock of a constant or random frequency to the glass bulb 1, and the high voltage generating power supply 10 generates a DC voltage or an AC voltage of several KV. The gas 7 introduced at a rate of several tens of liters per second through the gas introduction pipe 8 circulates through the glass bulb 1 and is sequentially discharged.

The gas 7 introduced into the glass bulb 1 is
It is ionized by discharge caused by application of a high voltage. When the high voltage is direct current, it is preferable to switch its positive / negative polarity halfway. When using an alternating current, a boosted sine wave commercial power supply or a rectangular wave low frequency power supply can be used. In any case, the charge of the foreign matter electrostatically adhered on the inner surface of the glass bulb 1 is eliminated or reduced by the neutralization, so that the mechanical shock by the vibrator 5 causes the connection to be broken. Then, the dropped foreign matter is discharged out of the glass bulb 1 together with the gas circulated in the glass bulb 1.

After the above treatment, the glass bulb 1
The picture tube is completed by inserting an electron gun therein and passing through sealing, exhausting, and aging processes.

[0010]

As described above, according to the present invention, it is possible to almost completely remove foreign matter that has remained unintentionally remaining in the glass bulb before the step of inserting the electron gun, thereby reducing the occurrence of sparks and stray emissions in the tube. Thus, a picture tube having excellent high voltage characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass bulb 2 Phosphor film 3 Aluminum vapor deposition film 5 Vibrator 7 Gas 9 Discharge needle 10 Power supply

Claims (1)

(57) [Claims] A gas inlet tube is provided in a glass bulb having a phosphor film and a metal back provided on an inner surface of a front wall .
Insert the discharge needle so as to protrude from the opening , apply a predetermined high voltage to the discharge needle while applying a mechanical shock to the glass bulb, and ground the anode button terminal connected to the metal back to ground. A method for manufacturing a picture tube, wherein the gas introduced into the glass bulb is ionized.