KR910007701B1 - Method of manufacturing a fluorescent screen of color picture tube - Google Patents

Abstract

The method is for keeping the specific gravity of the fluorescent slurry mixed with the solute of fluorescent material and the solvent of photosensitive resin constantly. The slurry (3') with certain specific gravity in a main tank (1) is sprayed on the panel (5) and the residual one is feedbacked after compensating the specific gravity. The feedbacked slurry is recovered to a mixing tank (V) of the mixing chamber (R) at which the solute and solvent are poured and mixed to keep the preset specific gravity and feedbacked to the main tank again.

Description

Manufacturing method of color CRT fluorescent surface

1 is a system diagram showing the configuration of a manufacturing apparatus for implementing a conventional fluorescent surface manufacturing method.

2 is a liquid-to-weight correlation of the phosphor slurry over time in the apparatus of FIG.

3 is a system diagram showing the configuration of a manufacturing apparatus for carrying out the fluorescent surface manufacturing method of the present invention.

4 is a liquid-specific gravity relationship with time of phosphor slurry in the main tank in the apparatus of the method of the present invention shown in FIG.

* Explanation of symbols for main parts of the drawings

1: main tank 3: phosphor slurry

3 ': phosphor slurry (in the mixing tank) 4: coating part

6: recovery part 7: recovery slurry

8: recovery tube 24: solute hopper

25: solvent hopper 26: solute valve

27 solvent valve 28 stirrer

29: mixing tank R: combination chamber

30: supplementary pipe V: mixing tank

The present invention relates to a method for producing a fluorescent surface of a color CRT, and more particularly, to a method of maintaining a specific gravity of a phosphor slurry obtained by mixing a solute such as a phosphor and a solvent such as a photosensitive resin in order to apply the fluorescent surface.

Shown in FIG. 1 is a system diagram of a device for implementing a conventional fluorescent surface manufacturing method, which is disclosed in Patent Publication No. 85-137.

In the conventional fluorescent surface manufacturing method, the phosphor slurry (3) is supplied from the main tank (1) through the supply pipe (2) to the applicator (4) by spray coating on the inner surface of the panel (5), and recovered from the recovery part (6). The surplus liquid of the phosphor slurry, that is, the recovery slurry (7) is recovered to the main tank (1) through the recovery pipe (8), in which the solid component of the phosphor slurry precipitates to the panel (5) side. Since it is adsorbed, the specific gravity is lowered compared to the supplied phosphor slurry (3). Accordingly, in the fluorescent surface manufacturing apparatus of Patent Publication No. 85-137 described above, the high specific gravity correction tank 10 filled with the high specific gravity phosphor slurry 9 and the low specific gravity correction tank 12 filled with the low specific gravity phosphor slurry 11 are provided. The main tank (1) according to the height of specific gravity of the phosphor slurry (3) extracted from the main tank (1) through the detection tube (13) through the detection tube (13) and detected by the detection unit (15). When the liquid level in the liquid is lowered and the floating switch 16 is opened, the low- or high-density phosphor slurry 10 or 9 is supplied to the main tank 1 from either of the correction tanks (or) layers, respectively. The amount consumed in 3) was supplemented and the specific gravity was corrected (S is the solenoid valve, P is the pump, and M is the stirrer).

However, such a conventional fluorescent surface manufacturing method has a number of problems as follows.

First, since the specific gravity adjustment of the phosphor slurry in the main tank is made by replenishing the consumed liquid level with a high and low specific gravity correction liquid, it is impossible to correct the specific gravity if the phosphor slurry is not consumed large enough to open the floating switch. Not only does the specific gravity decrease or increase, but even if the change in the specific gravity can be limited within a certain upper and lower limits, the specific gravity continues to change, which makes it difficult to apply effective spraying, and thus, the fluorescent film formed on the panel is not homogeneous. See also 2).

Second, even when the floating switch is opened at the appropriate time and the correction slurry is introduced into the main tank, the specific gravity is different because it is not uniformly mixed with the residual phosphor slurry in the main tank at the beginning of the input, and the specific gravity is different. If the spray coating is not expected to be homogeneous coating, it is preferable to stop the fluorescent surface coating operation in the initial stage of correction.

Third, some of the slurry of the large main tank was taken out to detect the specific gravity thereof, and accordingly the specific gravity was corrected.

Fourth, in connection with the second problem described above, the mixing and stirring of the correction liquid and the residual slurry into the main tank need not only be sufficiently and quickly achieved, but also the agitator must be enlarged because the object volume is the entire main tank. There is a problem that power consumption is also very large.

Fifth, the phosphor slurry can be used only after a long time of about 15 to 20 hours after the solute is added to the solvent, so that a plurality of main tanks are usually used to alternately use and stir, or It was common to install a mixing tank in a separate combination room to transfer the main tank after completion of stirring. Therefore, in the conventional technique shown in FIG. 1, the main mixing tank V1 for combining and stirring the phosphor slurry 3 of the main tank 1 into the mixing chamber R and the high specific gravity correction tank 10 A high specific gravity mixing tank V2 for combining and stirring the specific gravity phosphor slurry 9 and a low specific gravity mixing tank V3 for combining and stirring the low specific gravity phosphor slurry 11 of the low specific gravity correction tank 12 are respectively provided. Since the apparatus and piping are to be enlarged and become very complicated, there is a cumbersome problem because each concentration must be managed separately.

In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a uniform surface of the phosphor slurry in the main tank, which can maintain a constant specific gravity at all times regardless of the liquid level so that uniform application can be performed without stopping the application of the phosphor surface. It is to provide a manufacturing method.

Another object of the present invention is to provide a method for producing a fluorescent surface, which is possible to precisely correct the phosphor slurry, but is very simple to configure and manage as compared to the related art.

Another object of the present invention is to provide a method for producing a fluorescent surface which can significantly shorten the time required for forming the phosphor slurry by using the recovered slurry in combination and stirring the phosphor slurry.

In order to achieve the object of the present invention, a method for producing a color CRT fluorescent surface according to the present invention is a phosphor slurry of a predetermined ratio, which is combined and agitated in a mixing tank of a combination chamber and transferred to a main tank, is supplied from a main tank to apply and apply to a panel. In the method for producing a color CRT fluorescent surface for correcting the specific gravity of the recovery slurry after the completion of the recovery slurry to the main tank, the recovery slurry is recovered to the mixing tank of the combination chamber and the solute and the solvent are added and stirred to the phosphor of the set ratio. Forming a slurry is characterized in that the supply to the main tank.

Hereinafter, one preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 shows a manufacturing apparatus for carrying out the method of manufacturing the fluorescent screen of the present invention, a main tank 1 containing phosphor slurry 3, a supply pipe 2 extending from the coating part 4, and The phosphor slurry 3, which is located at the tip of the supply pipe 2 and is conveyed according to the set pressure, is sent to the nozzle 20 at a predetermined pressure to be applied to the inner surface of the panel 5, and the excess slurry is returned to the return tube 21. A slurry coating loop is formed as an injection control valve 22 returning to the main tank 1 through the main tank 1, and the main tank 1 is provided with an appropriate liquid level detector 23 such as a float switch. (28) is provided to continuously stir the phosphor slurry (3) so that solid components do not precipitate.

Shown in the box of one-dot chain line is a combination chamber (R), in which the solute hopper (24) containing solutes such as phosphors and the solvent hopper (25) containing solvents such as PVA are provided. A mixing tank (V) connected to and provided with an agitator (28) is installed. The mixing tank (V) is further connected with a recovery pipe (8) through which the recovery slurry (7) is transferred from the recovery section (6). The lower part is connected to the supplemental pipe 30 extending to the main tank 1 through the pump.

In this case, it is preferable that the control valve 22 and each pump with the subscript P are configured to be controlled by a controller (not shown), and an appropriate specific gravity detector is installed in the mixing tank V, and the solute hopper 24 and the solvent hopper 25 are provided. Appropriate dose control valves are preferably installed on the downstream side of

In addition, the above-mentioned recovery unit 6 rotates the panel 5 on the carrier 26 on which the coating is completed at high speed so that the recovery slurry 7 radiated outward by the centrifugal force causes the recovery pan 27 to recover. Therefore, it is preferable that the configuration to be introduced into the recovery pipe (8).

The apparatus of the fluorescent screen manufacturing method of the present invention having such a configuration operates as follows.

First, when the initial combination of the phosphor slurry 3 is to be opened, the solute hopper 24 and the solvent hopper 25 of the combination chamber R are first opened, and an appropriate amount of solute and solvent are added to the mixing tank V, respectively. By stirring with the stirrer 28 for an appropriate time (about 15 to 20 hours), a phosphor slurry 3 'of a predetermined setting ratio is formed and transferred to the main tank 1 through the supplemental pipe 30.

When the application of the fluorescent surface starts, the pump under the main tank 1 is started to transfer the phosphor slurry 3 to the supply pipe 2, and the injection control valve 22 supplies the transferred phosphor slurry 3 to a predetermined pressure. The excess slurry is returned to the return tube 21 in accordance with the set pressure so as to be supplied to the nozzle 20 and uniformly applied to the panel 5.

The panel 5 on which the phosphor is applied is covered with a recovery fan 27 and rotated at a high speed by the carrier 26. The recovery slurry 7 radiated according to the centrifugal force is transferred to the combination chamber (8) through the recovery tube 8. It is recovered to the mixing tank (V) of R).

The recovered slurry recovered in the mixing tank (V) detects the specific gravity with an appropriate specific gravity detector and injects an appropriate amount of solvent or solute from the solvent hopper 25 or the solute hopper 24 according to the height of the specific gravity. Re-stirring). At this time, the recovered slurry is already homogenized through stirring for 15 to 20 hours, so that only the specific gravity is deviated slightly from the set specific gravity. Therefore, the time required for re-stirring the solute or the solvent is about 1 to 3 hours. It will be a very short time.

In other words, in the manufacturing method of the color CRT fluorescent surface of the present invention, a new fluorescent substance slurry is formed using the recovery slurry as a base, and thus the time required for combining the fluorescent slurry in the continuous manufacturing process is 15 to 20. Significant savings from one to three hours in time.

When the coating is continued and the phosphor slurry 3 is consumed and the liquid level in the main tank 1 falls to the lower limit, the liquid level detector 23 detects this, and accordingly, in the mixing tank V of the combination chamber R, The phosphor slurry 3 'is transferred to the main tank 1 through the replenishment pipe 30 to replenish the phosphor slurry 3 so that the liquid level is the upper limit.

It should be noted that the phosphor slurry 3 'in the mixing tank V formed by the recovery slurry 7 is recovered and mixed and stirred with the solute or the solvent has a specific gravity and the specific gravity of the phosphor slurry 3 in the main tank 1. This is the most characteristic effect of the present invention in that it is supplemented with equal specific gravity.

In the embodiment described above, the liquid level of the phosphor slurry 3 in the main tank 1 is changed up and down between the upper and lower limits by the liquid level detector 23. However, in the present invention, the phosphor in the main tank 1 is changed. Since the stirring speed in the mixing tank V of the mixing chamber R is very fast compared to the consumption rate of the slurry 3, the phosphor slurry 3 ′ in the mixing tank V is continuously transferred into the main tank 1. The structure which keeps the liquid level of the main tank 1 substantially constant is also possible.

In the above-described embodiment, the solute hopper 24 and the solvent hopper 25 may be constituted by a high specific gravity slurry tank and a low specific gravity slurry tank, respectively.

As described above, according to the manufacturing method of the fluorescent surface, the phosphor slurry has a remarkable effect that the phosphor slurry is always uniformly maintained at a predetermined set ratio as shown in FIG. 4 regardless of the change in the liquid level of the main tank. There is an advantage that the quality is very uniform.

In addition, in the conventional technology, very complicated equipment and piping such as a high and low specific gravity correction tank and a mixing tank thereof are unnecessary, which significantly reduces the installation cost and the installation area and also facilitates the management thereof.

In particular, in the continuous coating process, the time required for the formation of the phosphor slurry is significantly shortened from 15 to 20 hours to 1 to 3 hours. Therefore, the preparation time for the coating is reduced, and a plurality of main tanks are alternately used or stirred. There is no inconvenience in doing this.

Due to such various advantages, the method of manufacturing the fluorescent screen of the present invention is a very useful invention that can contribute to producing high quality and high quality color CRTs economically and productively.

Claims (1)

Phosphor slurry 3 'of a predetermined set specific gravity, which is combined and stirred in the mixing tank V of the combining chamber R, and transferred to the main tank 1, is supplied from the main tank 1 and applied to the panel 5. In the manufacturing method of the color CRT fluorescent surface which correct | restores the specific gravity of the collection | recovery slurry (7) after performing application | coating, and returns to the main tank (1), the said collection slurry (7) is the mixing tank (V) of the said combination chamber (R). ), The solute and the solvent are added and stirred to form the phosphor slurry (3 ') in the set ratio and supplied to the main tank (1).

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