JPH09199034A - Manufacture of cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a cathode-ray tube which can eliminate an inferior vacuum generated because a fine through-hole is left in a seal part of an exhaust pipe. SOLUTION: In a method of manufacturing a cathode-ray tube, providing a glass-made exhaust pipe 1 in a cathod-ray tube bulb 3, connecting the cathode- ray tube bulb 3 to an exhaust device through the exhaust pipe, heating exhausting the cathode-ray tube bulb thereafter heating fusing partly the exhaust pipe sealed, and then cutting off a seal part of this exhaust pipe, after sealing the exhaust pipe, external diametric dimension of its seal part is measured, based on this measured value, so as to determine whether seal part cutting is good or bad.

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, and more particularly to a method for manufacturing a cathode ray tube in which a vacuum defect due to a leak from a sealing portion of an exhaust tube is prevented.

[0002]

2. Description of the Related Art Generally, in a cathode ray tube, a phosphor screen and other in-tube members are provided inside a bulb composed of a face portion and a funnel-shaped funnel portion, and then an electron gun is inserted into the neck of the funnel portion. The stem with the exhaust pipe attached to this electron gun and the neck are welded to seal the electron gun in the neck. Next, the sealed valve of this electron gun is connected to an exhaust device via an exhaust pipe, and the valve and the pipe inner member provided in the valve are heated to release the adsorbed gas from the valve and the pipe inner member. Evacuate the inside of the valve to a high vacuum. After the exhaust process, high-frequency heating of each electrode of the electron gun, decomposition activation of the cathode, etc. were performed, and then a part of the exhaust pipe was heated and melted by a cylindrical electric heater surrounding it to seal it. To do. After that, it is manufactured by a method of cutting the sealing portion of the exhaust pipe.

Particularly in the case of continuously mass-producing cathode ray tubes, a valve with a sealed electron gun is attached to an exhaust cart equipped with an exhaust device to evacuate the exhaust tube, and then the exhaust tube is exhausted. The valve is transferred from the exhaust device to the cutting device and the sealing portion is cut.

[0004]

As described above, generally, in a cathode ray tube, various tube members are provided in the bulb, and then the electron gun is sealed in the neck of the bulb. Is connected to an exhaust device via an exhaust pipe to heat and exhaust it, then a part of the exhaust pipe is heated and melted by an electric heater to seal it, and then it is cut by the sealing part of this exhaust pipe. Has been done.

However, when the cathode ray tube is manufactured by the above method, the sealing portion of the exhaust pipe may not be sufficiently heated due to deterioration of the electric heater or eccentricity of the electric heater with respect to the exhaust pipe, or the sealing portion may be damaged. Heated unevenly,
It may be cut with the minute through holes remaining in the sealing portion.

Such a cathode ray tube is removed as a vacuum defect in the subsequent inspection process due to a leak from the minute through hole, but it is not detected in the inspection process, and becomes a vacuum defect after it is put on the market. There is.

The present invention has been made in view of the above problems, and provides a method of manufacturing a cathode ray tube capable of eliminating a vacuum defect caused by a minute through hole remaining in a sealing portion of an exhaust tube. With the goal.

[0008]

A cathode ray tube valve provided with a glass exhaust pipe is connected to an exhaust device through the exhaust pipe, and after heating and exhausting the cathode ray tube valve, a part of the exhaust pipe. In the manufacturing method of the cathode ray tube, which heat-melts and seals, and then cuts the sealing portion of the exhaust pipe, after measuring the outer diameter dimension of the sealing portion of the exhaust pipe after sealing the exhaust pipe, Whether to cut the sealing portion is determined based on the measured value.

Further, the outer diameter dimension of the sealing portion of the exhaust pipe is measured, and if the outer diameter dimension of this sealing portion is less than or equal to a reference value, the sealing portion is cut, and if it is greater than the reference value, sealing is performed. The parts were again heated and melted.

Further, the outer diameter of the sealed portion at the limit of disappearance of the minute through holes communicating with the cathode ray tube bulb in the sealed portion was used as a reference value.

[0011]

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

Generally, a cathode ray tube is manufactured by the process shown in FIG. That is, in the bulb manufacturing process, a phosphor screen and other in-tube members are provided inside a glass bulb having a funnel-shaped funnel portion having a face portion and a neck portion at one end. In a normal cathode ray tube, various tube inner members are provided inside the bulb composed of a face portion and a funnel portion which are formed in advance. A shadow mask is attached to the face portion where the body screen is formed, and a funnel portion is joined to the face portion where the shadow mask is attached.

Next, the electron gun is sealed in the neck of the valve manufactured as described above (electron gun sealing step). This electron gun is sealed by attaching a stem with an exhaust pipe to the assembled electron gun in advance and welding the flared portion of the stem and the neck. Next, the sealed valve of the electron gun is connected to an exhaust device through an exhaust pipe, and the valve and the pipe inner member provided in the valve are heated to release the adsorbed gas from the valve and the pipe inner member. At the same time, the inside of the valve is evacuated to a high vacuum (evacuation step). In this exhaust step, in the subsequent stage, high-frequency heating of the electrode of the electron gun and decomposition activation of the cathode are performed, and then, a part of the exhaust pipe is heated and melted and sealed, and then the sealing portion of this exhaust pipe. Is cut.

The valve exhausted as described above is then subjected to a getter flash for further increasing the vacuum inside the valve, aging for improving and stabilizing electron emission from the cathode, withstand voltage treatment for increasing withstand voltage, and inspection. Manufactured.

In the above exhausting process, when the sealed valve of the electron gun is attached to the exhaust cart to exhaust the air, FIG.
, The exhaust pipe 1 is airtightly attached to the port 2 of the exhaust cart, connected to the exhaust device mounted on the exhaust cart, and the valve 3 attached to the exhaust cart is put in the heating furnace to 3 and the pipe inner member provided in the valve are heated and evacuated. In this case, the electric heater 4 is coaxially arranged around the exhaust pipe 1, and after the exhaust is completed, the electric heater 4 is energized to heat and melt a part of the exhaust pipe 1 to seal it. Then, the cutting of the sealing portion of the exhaust pipe 1 is performed by transferring the valve 3 with the sealed exhaust pipe 1 from the exhaust cart to the cutting device.

The bulb 3 shown in FIG. 1 is a bulb of a color cathode ray tube, 5 is a face portion, 6 is a funnel portion, 7 is a phosphor screen provided on the inner surface of the face portion 5, and 8 is the same. A shadow mask placed inside, 9
Is an electron gun sealed in the neck 10 of the funnel 6.

Particularly in this embodiment, when cutting the sealing portion of the exhaust pipe 1, as shown in FIG. 2, the outer diameter of the sealing portion 12 of the exhaust pipe 1 which is sealed by the heating of the electric heater. When the dimension is measured, and the outer diameter dimension is less than the reference value D1, as shown in FIG. 6, the outer diameter dimension D2 is smaller than the reference value D1 as shown in FIG. big,
When there is a possibility that the minute through holes 13 remain, the sealing portion 12 is heated and melted again by the electric heater, and after the sealing portion 12 becomes the reference value D1 or less, it is cut and fed to the next step. The reference value D1 of the outer diameter dimension of the sealing portion 12 is determined by, for example, measuring the outer diameter dimension by the following method, the sealing portion 12 is completely welded and the minute through holes 13 disappear, and no leak occurs. The critical dimension or a value slightly smaller than this critical dimension is used as the reference value D1.

The outer diameter of the sealing portion is preferably measured in a non-contact manner. As shown in FIG. 4 (a), two laser beam projection portions 15a, 15a, are provided on one side of the sealing portion 12. 15b
Are arranged so that they can be contacted and separated from each other, and the laser light detection unit 16 is arranged opposite to the other side with the sealing unit 12 interposed therebetween. For example, by rotating a sealed valve of the exhaust pipe, two laser light projection units 15a, 15
The maximum outer diameter of the sealing portion 12 that can be detected by the laser light detecting portion 16 without the laser light 17a and 17b from b being blocked by the sealing portion 12 is determined by the laser light detecting position of the laser light detecting portion 16 or the laser light projection. It can be measured by obtaining from the interval between the parts 15a and 15b. Further, as shown in (b), one laser beam projection unit 15 is disposed on one side of the sealing unit 12, and a laser beam detecting unit 16 is disposed on the other side of the sealing unit 12 so as to face each other. Arrow 18 while rotating the sealed valve
It can be measured by moving at a constant speed in the direction, and obtaining the maximum outer diameter of the sealing portion 12 from this moving speed and the detection of the laser light 17 of the laser light detecting portion 16.

As described above, the reference value D1 of the outer diameter dimension of the sealing portion 12 of the exhaust pipe 1 is determined, and the outer diameter dimension is the reference value D.
If the sealing portion 12 is cut only when it is 1 or less, and if it is larger than the reference value D1, it is heated and melted again without cutting, and when the sealing portion 12 is cut after the reference value D1 or less, the electric heater 4 As shown in FIG. 3, the outer diameter dimension of the sealing portion 12 is larger than the reference value D1 due to the deterioration of the temperature of the exhaust pipe 1 and the uneven heating of the electric heater 4 with respect to the exhaust pipe 1.
It is possible to remove the remaining minute through-holes 13, and it is possible to eliminate the occurrence of vacuum defects due to leakage from the sealing portion 12 of the exhaust pipe 1.

That is, the outer diameter of the exhaust pipe is about 9.3 mm.
With respect to the 17-inch color display tube of No. 2, the heating condition of the electric heater was changed and the outer diameter dimension of the sealing portion was measured, and the result shown by the curve 20 in FIG. 7 was obtained.

That is, the outer diameter of the exhaust pipe is about 9.3 mm.
In this case, when the outer diameter of the sealing portion is 5.0 mm or less, no minute through hole is generated, and the leakage from the sealing portion is 100%. However, when the outer diameter of the sealing part becomes 5.5 mm,
When the minute through holes are 10% and 6.5 mm, 50% and 7.
When it is 0 mm or more, 100% occurs. Therefore, for a cathode ray tube with an outer diameter of the exhaust tube of about 9.3 mm, a cathode ray tube that does not become defective in vacuum is manufactured by cutting the outer diameter of the sealed portion to 5.0 mm as a reference value. can do.

[0022]

As described above, the cathode ray tube valve provided with the glass exhaust pipe is connected to the exhaust device through the exhaust pipe, and after heating and exhausting the cathode ray tube valve, a part of the exhaust pipe is removed. In the method of manufacturing a cathode ray tube in which heating and melting are performed and sealing is performed, and then the sealing of the exhaust pipe is cut, in the method of manufacturing the cathode-ray tube, after sealing the exhaust pipe, the outer diameter dimension of the sealing portion of the exhaust pipe is measured to determine the sealing portion. Decide whether to cut, further, if the outer diameter dimension of the sealing portion is less than the reference value, cut at the sealing portion, if it is larger than the reference value, the sealing portion should be heated and melted again. ,
It is possible to remove those in which the minute through holes remain in the sealing portion, and it is possible to completely eliminate a vacuum defect due to a leak from the sealing portion of the exhaust pipe.

[Brief description of drawings]

FIG. 1 is a diagram for explaining exhaust of a valve of a color cathode ray tube according to an embodiment of the present invention.

FIG. 2 (a) is a diagram showing a sealing portion of an exhaust pipe whose outer diameter dimension is a reference value, and FIG. 2 (b) is a BB sectional view thereof.

FIG. 3 (a) is a view showing a sealing portion of an exhaust pipe having an outer diameter dimension larger than a reference value, and FIG. 3 (b) is a BB sectional view thereof.

4 (a) and 4 (b) are diagrams for explaining a method of measuring an outer diameter dimension of a sealing portion of an exhaust pipe.

FIG. 5 is a process drawing for explaining the manufacturing method of the cathode ray tube.

FIG. 6 is a diagram for explaining a method of cutting the sealing portion of the exhaust pipe.

FIG. 7 is a diagram showing the relationship between the outer diameter dimension of the sealing portion of the exhaust pipe and the incidence rate of minute through holes.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Exhaust pipe 3 ... Valve 4 ... Electrothermal heater 12 ... Exhaust pipe sealing part 13 ... Micro through hole

Claims (3)

[Claims] 1. A cathode ray tube valve provided with a glass exhaust pipe is connected to an exhaust device through the exhaust pipe, the cathode ray tube valve is heated and exhausted, and then a part of the exhaust pipe is heated and melted. In a method of manufacturing a cathode ray tube, which comprises sealing and then cutting the sealing portion of the exhaust pipe, after measuring the outer diameter of the sealing portion of the exhaust pipe after sealing the exhaust pipe, based on the measured value A method of manufacturing a cathode ray tube, characterized by determining whether or not the sealing portion can be cut. 2. The outer diameter dimension of the sealing portion of the exhaust pipe is measured, and when the outer diameter dimension of the sealing portion is less than or equal to a reference value, the sealing portion is cut, and when it is greater than the reference value, the above The method of manufacturing a cathode ray tube according to claim 1, wherein the sealing portion is heated and melted again. 3. The method of manufacturing a cathode ray tube according to claim 2, wherein the reference value is an outer diameter dimension of the sealing portion at the limit where the minute through holes communicating with the cathode ray tube bulb disappear in the sealing portion.