JP3320602B2 - Manufacturing method of cathode ray tube - Google Patents

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 an interior graphite conductive film is formed by a flow coating method.

[0002]

2. Description of the Related Art In general, a color cathode ray tube comprises a funnel, a panel having a fluorescent screen formed therein, and a neck tube located behind the funnel. The color cathode ray tube uses an electron beam emitted from an electron gun provided inside the neck tube portion as a color selection electrode by using a shadow mask arranged at a predetermined interval from the phosphor screen inside the panel portion. A color image is drawn by projecting on predetermined phosphor dots forming a phosphor screen.

For this reason, graphite is provided on the inner wall of the funnel as an electrode for maintaining the potential in the tube constant, as a conductive film for connecting the anode button to which a high voltage is applied from the outside with the fluorescent screen and the final electrode of the electron gun. And the like. The interior graphite conductive film serves as a part of the color picture tube driving circuit by forming a capacitor between the interior graphite conductive film and the exterior graphite film applied on the outer surface of the funnel.

[0004] As one of the coating methods of the interior graphite conductive film, there is a flow coating method (flow coating method). In this flow coating method, generally, graphite slurry is generally injected from the inside of the panel joint portion of the funnel to the neck tube side, which is easier to control and more mass-produced than the conventional brush coating method or the like. It has the advantage of. However, in this flow coating method, the coating film is once formed to the tip side of the conduction spring with the electron gun inside the neck tube part where the interior graphite conductive film should not adhere, so it is necessary to remove this. There is.

[0005] As a method for removing the unnecessary coating film inside the neck tube portion, the following method has conventionally been performed. After applying the graphite slurry to the entire coating area on the inner wall of the funnel including the inside of the neck tube, wash it with deionized water or wipe it with a rubber wiper while the coating film is not sufficiently dried. The coating film is removed to a temporary coating film edge on the anode button side from a certain predetermined range region, and the coating film is completely dried. Thereafter, the glass is further washed with a solution such as hydrofluoric acid, ammonium fluoride water or the like that dissolves the glass at a distance of about 10 [mm] or more from the end of the temporary coating film. Completely dissolve and remove. Then, it is sufficiently washed again with deionized water, and finally, a portion of the temporary coating film above the edge is slid and applied with a tampon or the like impregnated with graphite slurry to reach a predetermined position. An interior graphite conductive film is formed (Japanese Patent Publication No. 2-7137).

[0006]

However, in the above-mentioned conventional method, it is necessary to remove the coating film more than a predetermined range region in advance, and then re-apply graphite slurry to a predetermined position. The number of processes increases.

Further, in order to prevent discharge and the like from being generated on the inner wall of the neck tube portion, in order to completely peel off and remove remaining stains such as graphite and metal oxide, hydrofluoric acid containing fluorine is used. It must be repeatedly washed with a solution that dissolves glass such as aqueous ammonium fluoride. in this way,
When a solvent containing fluorine is used, the fluorine is adsorbed on the interior graphite conductive film and easily remains in the cathode ray tube. Finally, after the inside of the cathode ray tube is evacuated, the fluorine is released and adheres to the cathode. As a result, the emission deteriorates and the life of the cathode ray tube is adversely affected.

Further, handling of hydrofluoric acid, aqueous ammonium fluoride, etc. is dangerous, and various measures must be taken to protect the environment, such as the problem of waste liquid treatment. Costs rise.

In the conventional method of drying only the graphite coating on the funnel interior by adjusting the heater and air blow and drying the coating on the neck tube, the temperature of the neck tube fluctuates and the deionized water is removed. Variation occurs in the complete removal of the excess coating film by washing only.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a color cathode ray tube which does not adversely affect the life of a cathode ray tube while satisfactorily washing away an excessive coating film inside a neck tube portion. An object of the present invention is to provide a method for manufacturing a tube.

[0011]

In order to achieve the above object, a method of manufacturing a cathode ray tube according to the present invention comprises the steps of: flowing a graphite slurry into an inner surface of a funnel; and drying the graphite slurry to form an inner surface of the funnel. the method of manufacturing a color cathode-ray tube forming the interior graphite conductive film, before
The drying is performed by using an air blow, and an unnecessary portion of the interior graphite conductive film is removed by an ultrasonic humidifier during the drying.
The humidification is carried out by spraying to keep the unnecessary portions from drying out, and then the moistened unnecessary portions are washed and removed. Therefore, unnecessary portions of the interior graphite conductive film are in a sufficiently wet state, so that an excess coating film can be surely removed by washing with only deionized water.

Alternatively , at the time of the drying, the funnel is
Rinse with deionized water on the outer surface of the neck tube
To prevent the rise in temperature,
It is also effective to keep moist so that unnecessary parts of the electromembrane do not dry
It is a target.

[0013]

[0014]

[0015]

[0016]

Embodiments of the present invention will be described below with reference to the drawings. The apparatus for manufacturing a color cathode ray tube according to the present embodiment includes an inflow means (not shown) for flowing graphite slurry into the inner surface of the funnel in order to form an interior graphite conductive film on the inner surface of the funnel, and a drying device for drying the graphite slurry. Air blow 1 and heater 2 as means, deionized water rinse 6 and ultrasonic humidifier 10 as moisturizing means for moisturizing unnecessary portions of graphite slurry,
The cleaning means (not shown) for cleaning and removing unnecessary portions of the graphite slurry.

In the method of manufacturing a color cathode ray tube according to the present embodiment, when the coating film is dried by the air blow 1 and the heater 2, the graphite coating film of the neck tube portion 7 is simultaneously coated with the ultrasonic humidifier 10. Ultrasonic humidification. The ultrasonic humidifier 10 has a cartridge tank, and a specific humidifying means is a stainless steel humidifier 10 which is inserted from the ultrasonic humidifier 10 into the inner surface of the neck tube portion 7 through a humidifying hose 9 made of vinyl chloride. The spray is applied from the nozzle 8. By doing so, the graphite coating on the inner surface side of the neck tube 7 can be sufficiently humidified and the temperature rise near the neck tube 7 can be suppressed when the coating is dried. Drying of the conductive coating on the inner surface can be prevented.

Further, by rinsing the outer surface of the neck tube 7 with deionized water, it is possible to prevent the temperature of the neck tube 7 from rising, so that not only the inner coating film surface but also the inner surface of the coating film can be prevented. (The side in contact with the inner wall of the neck tube portion) can also be prevented from drying. Further, when the outer surface of the neck tube portion 7 is rinsed 6 with ion water as described above,
Since the temperature of the neck tube portion 7 in the region where the interior graphite conductive film should not be applied can be kept constant, the influence of heat for drying the funnel on the upper surface can be suppressed,
In particular, a stable wet state can be maintained without being affected by the surrounding environmental temperature.

The method of applying the inner coating film before the drying step described in this embodiment is the same as the conventional method. The heater 2 for drying the coating film is a flat black heater 4 × 2 [kw]
And the flow rate of the air blow 1 is 200 to 500 [l
/ Min] depending on the mode of drying of the coating film. At this time, if the heater capacity is too small, the interior graphite coating film 4 cannot be transferred to the next step without drying forever. Conversely, if it is too large, the interior graphite coating film 4 will dry rapidly and cracks will occur on the coating surface, causing high pressure failure.

If the air flow rate is too small, the interior graphite coating film 4 does not dry, and if it is too large, drying tends to be uneven, and the spraying by the ultrasonic humidifier 10 applied to the inside of the neck tube 7 is affected. As a result, the humidifying effect is lost.

The direction of the air is desirably adjusted so that only the cone portion of the funnel dries, and the drying time is desirably about 1 minute. If dried too quickly, components such as black smoke in the black smoke slurry used at the time of coating the inner surface coating may be separated, causing cracks in the dried coating, resulting in poor conduction when the cathode ray tube is completed. It is.

The humidifying capacity of the ultrasonic humidifier 10 is 3
00 to 500 [ml / h], capacity of tank is 3 to 5
[1] is preferable. If the humidification capacity is too small, sufficient humidification cannot be supplied, and the humidification effect is lost. On the other hand, if the capacity of the tank is too small, the frequency of exchange of deionized water increases, and if it is too large, a large installation space is required. Therefore, each condition is examined, and the ultrasonic humidifier 10 and the tank having a preferable capacity are appropriately selected.

The nozzle 8 for supplying the spray is a stainless steel pipe having an outer diameter of about 6 to 8 [mm] with holes having a diameter of about 1 to 2 [mm] formed at regular intervals. The area from the neck seal line joining the neck tube 7 to the funnel to the flare provided to facilitate insertion of the electron gun at the tip of the neck tube can be humidified.

The humidifying hose 9 connecting the ultrasonic humidifier 10 and the humidifying nozzle 8 has an inner diameter of 20 to 30 mm.
Select a grade of polyvinyl chloride tetron grade hose. If the pipe diameter of the humidifying nozzle 8 is too large, it comes into contact with the neck tube portion 7 and the glass surface is damaged. If it is too small, the spray amount is suppressed. If the diameter of the hole provided in the humidifying nozzle 8 is too small, graphite slurry adheres to the hole and the hole is clogged, and spray cannot be supplied. And the interior graphite coating film 4 cannot be dried. As the humidifying hose 9, a Tetron grade hose having characteristics that it is not easily deformed and has excellent durability is selected.

The nozzle 8 is fixed, and the distance a from the neck seal line 5 to the tip of the nozzle is 20 ± 5 [m
m]. If the distance from the neck seal line 5 to the nozzle tip is too short, the interior graphite coating film 4 cannot be dried by humidification to an extra area, and if it is too long, sufficient wetness can be supplied to a predetermined area. become unable.

The amount of water in the rinse 6 by deionized water from the outer surface of the neck tube 7 is about 1 [l / min], and the water temperature is 20 ±
The temperature is adjusted to 5 [° C]. When the rinsing 6 with deionized water is performed on the outer wall of the neck tube 7 in this manner, in addition to the effect of preventing the temperature rise of the interior graphite coating film 4 of the neck tube 7, the outer wall and the flare portion of the neck tube 7 are prevented. At the same time, an effect that unnecessary graphite and the like attached to the surface can be removed is obtained. If the graphite adheres to the outer wall of the neck tube part 7, it causes an undesired line spark in the deflection yoke mounted at the time of operation of the cathode ray tube. Further, when the electron gun is inserted in a later electron gun sealing step, the graphite in the flared portion may be carried to the inner wall of the neck tube portion 7 by an electrode, a conduction spring or the like. Then, even if unnecessary graphite on the inner wall of the bent neck tube is removed, a high pressure failure or the like occurs as a result.
Therefore, rinsing 6 with deionized water on the outer wall of the neck tube 7 is very effective.

According to the present embodiment, the ultrasonic humidifier 10
Is used, it is possible to supply moisture to the coating surface and the inner surface of the neck tube 7, and it is possible to always keep the interior graphite coating 4 of the neck tube 7 in a wet state. Therefore, in the cleaning process, all of the 50 test pieces can sufficiently remove the excess graphite slurry in the neck tube only with deionized water, and the production process time can be reduced from 300 seconds to 200 seconds. It could be confirmed.

In this embodiment, the case where both humidification and cooling are performed simultaneously has been described. However, the present invention is not limited to this, and only one of them may be performed according to the embodiment. It is possible.

Further, in the present embodiment, a method using spraying by the ultrasonic humidifier 10 has been described as a humidifying method, but the present invention is not limited to this, and a predetermined amount of water is uniformly provided. The same effect as the present invention can be obtained even with other means that can be used.

In the above-described embodiment, the case where the cathode ray tube manufacturing method of the present invention is applied to a color cathode ray tube has been described. However, the present invention can obtain the same effect even when used in a monochrome cathode ray tube. .

[0031]

According to the method for manufacturing a cathode ray tube according to the present invention,
If graphite slurry of the neck tube portion is humidified or cooling in a coating fabric drying step, coating of the neck tube portion is kept wet, unnecessary portions of the coating film can be easily removed only by deionized water it can.

Therefore, a production process such as a process of repainting the graphite slurry becomes unnecessary, and the production process time can be reduced by 30%. Further, unnecessary portions of the coating film can be removed without using a solution that dissolves glass, such as hydrofluoric acid and ammonium fluoride aqueous solution containing fluorine, so that fluorine does not adhere to the cathode, Emission deterioration can be prevented,
The life of the cathode ray tube is not adversely affected. Further, since it is not necessary to use hydrofluoric acid, aqueous ammonium fluoride, or the like, the problem of working environment safety can be solved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a configuration of a method for manufacturing a color cathode ray tube according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 air blow 2 heater 3 funnel 4 interior graphite conductive film 5 neck seal line 6 deionized water rinse 7 neck tube 8 humidification nozzle 9 humidification hose 10 ultrasonic humidifier a Distance from neck seal line to nozzle tip

Continuation of the front page (56) References JP-A-52-30155 (JP, A) JP-A-7-217955 (JP, A) JP-A-7-85787 (JP, A) JP-A-9-7511 (JP, A) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 9/20

Claims (2)

(57) [Claims] [Claim 1] After flowing graphite slurry on the inner surface of the funnel, in the manufacturing method of a color cathode-ray tube forming the interior graphite conductive film on the inner surface of the funnel by drying the graphite slurry, the air blowing said drying
Along with the use , during the drying, the unnecessary portion of the interior graphite conductive film is humidified by spraying an ultrasonic humidifier,
A method for manufacturing a cathode ray tube, comprising: moisturizing the unnecessary portion so as not to dry; and thereafter, washing and removing the moistened unnecessary portion. 2. A graphite slurry flows into the inner surface of the funnel.
Then, by drying the graphite slurry,
A color shade that forms an interior graphite conductive film on the inner surface of the funnel
In the method for manufacturing a pole tube, the fan may be used during the drying.
The deionized water is applied to the outer surface of the
To prevent the temperature from rising,
Moisturize the unnecessary parts of the graphite conductive film so that they do not dry,
Washing and removing the unnecessary portion after moisturizing.
Of manufacturing a cathode ray tube .