JPS63111970A - Method for coating phosphor slurry - Google Patents

Abstract

PURPOSE:To save the manpower of a compounding stage and to improve the efficiency by fully automating the compounding stage for a slurry for replenishment in a coating operation of a phosphor slurry and incorporating automatic compounding device thereof into the coating line of the phosphor slurry. CONSTITUTION:After the phosphor 1 is injected and coated on the inside surface of a glass panel, the glass panel is rotated at a high speed to shake of the excess component of the phosphor slurry. Said slurry is recovered and the slurry for replenishment of the amt. corresponding to the amt. of the slurry consumed at the time of coating on the inside surface of the glass panel is automatically replenished. The automatic compounding device 20, 34 for the slurry for replenishment are incorporated into automatic coaters 3, 4 for the fluorescent surface. At least >=2 kinds among a PVA soln., ammonium dichromate, pure water, surfactant soln., and ethylene glycol are respectively discretely added by said automatic compounding device to the phosphor to prepare the slurry for replenishment. As a result, the manpower of the compounding stage is saved and the efficiency thereof is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method for applying phosphor slurry that is applied when forming a phosphor screen on the inner surface of a glass panel constituting a color picture tube or cathode ray tube for display. It is something.

[Prior Art] Normally, a phosphor screen of a color picture tube or the like is formed by an automatic machine in which a carrier having fixed glass panels is arranged in a loop and is sequentially moved at a predetermined cycle time. In the process of forming the color picture tube phosphor screen, a photosensitive binder such as a solution containing polyvinyl alcohol (hereinafter referred to as PVA) and ammonium dichromate (hereinafter referred to as ADC) as main components is added to a predetermined amount. After suspending the phosphor into a phosphor slurry and applying it to the inner surface of the glass panel and drying it, the phosphor of a predetermined size is placed at a desired position by an exposure device through a shadow mask that serves as a color selection electrode. Stripes or phosphor dots (hereinafter collectively referred to as phosphor stripes) are formed, and this process is performed on three types of phosphor slurries: green, blue, and red, thereby forming positions corresponding to the openings of the shadow mask. Three types of phosphor stripes are formed on the surface.

Since the phosphor slurry used to form such phosphor screens is expensive, it is common practice to collect the excess during the coating process, make the necessary composition adjustments, and use it again as slurry for forming phosphor screens. be. FIG. 3 shows an automatic phosphor screen coating apparatus that applies, collects, and supplies this phosphor slurry.

A more detailed explanation will be given below using FIG. 3.

While holding the glass panel (2) in a carrier (not shown) and rotating it, a drive source motor (5) is connected to a pump (4) having a threaded structure built into the bottom of the slurry tank for injection (3). The driving force is transmitted to the pump (4) via a reduction mechanism (6) such as a pulley and a belt.
is activated to forcefully feed the phosphor slurry (1) maintained at a constant volume in the injection slurry tank (3), and inject a constant amount into the glass panel (2) by opening and closing the solenoid valve (7). . In this case, the phosphor slurry (1) can be spread over the required area on the inner surface of the glass panel (2) by appropriately adjusting the inclination and rotation speed of the glass panel (2).

After applying the phosphor slurry (1) in this manner, the glass panel (2) is rotated at high speed to remove excess phosphor slurry (1) from the collection container (8) arranged around the glass panel (2). ) and collected by centrifugal force, and returned to the slurry tank (3) through the pipe (9). The amount consumed, that is, the amount reduced due to the application of the phosphor slurry (1) to the inner surface of the glass panel (2), is replenished in a separate replenishment tank (10), including adjustment of the slurry composition. slurry (11) is automatically replenished.

Glass panel after shaking off excess phosphor slurry (1) (
2) proceeds to the next drying process and exposure process, and most of the above-mentioned phosphor slurry (1) is transferred from the injection slurry tank (3) to the solenoid valve (7), the glass panel (2), and the collection container. (8) and then returns to the injection slurry tank (3), repeating the circulation.

The above-mentioned replenishment slurry (11) is checked by checking the remaining amount of the replenishment tank (lO) by line patrols and liquid level detection signals, and when the remaining amount is below a certain level, the tank (10) itself is removed. change. In this case, a fully charged replenishment tank (10) is taken out of the mixing chamber for mixing phosphor slurry and replaced with a tank that has been depleted.

Normally, the capacity of the supply tank (IQ) is 60 to 70 so
About i amount of slurry has been added. Further, the replenishment slurry (11) is prepared in a batch manner using a larger mixing tank to prepare approximately 150 batches at a time.

FIG. 4 shows the mixing process of the above replenishment slurry (11), and the mixing process will be explained in detail below based on the same figure.

First, after weighing the necessary phosphor for the total amount of a1,
By adding a predetermined amount of pure water and gradually adding the above-mentioned weighed phosphor while scrubbing, the dispersion of the phosphor into water is completed.

Next, a predetermined amount of 10% PVA aqueous solution is weighed and added to the mixing tank, and stirring is continued. Furthermore, the acrylic emulsion, 10% aqueous solution of ADC, and surfactant are added in this order to complete the preparation.

Next, it is determined whether the slurry has been made to the specified composition by checking the specific gravity of the slurry and the amount of organic components burned. In other words, analyze the composition.

If the set value is not reached, the composition is adjusted and only the replenishment slurry having a composition that passes the specifications is put into the line.

[Problems to be Solved by the Invention] According to the conventional mixing method described above, it is necessary to individually measure the weight and volume of the constituent materials of the slurry, which requires a great deal of effort and time. . Further, it is necessary to transport and replace the replenishment slurry between the mixing room and the line for the phosphor slurries for three colors, and this also requires a considerable amount of manpower.

Furthermore, in addition to a large-capacity mixing tank, it is necessary to store and manage a plurality of supply tanks in the mixing room, resulting in an extremely large-scale facility.

Furthermore, there was also a problem with respect to changes over time after the phosphor was prepared. In other words, in order to increase the efficiency of mixing, approximately 150 tons of 10 tons are mixed, but in this case, even with the same mixing rod, the characteristics of the slurry change over time, which has a negative impact on product quality and yield. there were.

This invention was made to solve the above-mentioned problems, and it is possible to save labor and improve efficiency in the slurry preparation process, and to suppress fluctuations in product quality and yield due to changes in slurry characteristics over time. It is an object of the present invention to provide a method for applying a phosphor slurry that can be applied.

[Means for Solving the Problems] A method for applying a phosphor slurry according to the present invention includes applying at least two of PVA solution, ADC1 pure water, a surfactant, and ethylene glycol individually to the phosphor. The present invention is characterized in that an automatic replenishment slurry mixing device that adds and mixes the replenishment slurry to a replenishment slurry is incorporated into an automatic fluorescent screen coating device.

[Function] According to the present invention, the automatic phosphor screen coating device automatically and continuously applies the phosphor slurry, such as injecting the phosphor slurry onto the inner surface of the glass panel and shaking off and collecting the excess phosphor slurry. To automatically replenish slurry in an amount corresponding to the amount of phosphor slurry consumed during automatic application of the phosphor slurry. This replenishment slurry is also automatically mixed by the automatic mixing device and automatically replenished to the automatic coating process. Therefore, there is no need to manually transport the replenishment slurry or replace the tank, thereby saving labor and improving the efficiency of the phosphor slurry coating operation.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 shows a cross-sectional view of the main parts of the device for explaining one embodiment of the present invention, and the portion surrounded by broken lines in the figure is
Only the main parts of the automatic phosphor screen coating apparatus shown in FIG. 3 are shown, and the same components as in FIG. 3 are given the same reference numerals and detailed explanations will be omitted.

In FIG. 1, (lO) is a supply tank, which is fixedly installed and has a capacity of about 20 liters. (20) is a mixing tank, which is equipped with a rotary grabber (35) and a liquid level control device (21).

(27) is a quantitative supply device for phosphor (28), and (23) is a pure water supply pipe, which is equipped with a solenoid valve (28a).

(24) is a supply pipe for PVA aqueous solution, and a gear pump (
25) and a solenoid valve (28b). (31) is an ADC supply pipe, which is equipped with a metering pump (30a) and a solenoid valve (28c). (32) is a supply pipe for the surfactant solution, which includes a metering pump (3ob) and a solenoid valve (2[
3d). (33) is the ethylene glycol supply pipe, which includes a metering pump (30c) and a solenoid valve (2
13e). Quantitative supply device (27)
and each supply pipe (23), (24), (31)~
(33) is connected to the mixing tank (20).

(36) is connected to the supply tank (I) from the mixing tank (20).
It is a replenishment pipe for reinforcing slurry to Q), and is a pump (37).
and a specific gravity measuring device that continuously measures the specific gravity of replenishment slurry (
29) and a three-way solenoid valve (22) are interposed.

(38) is a slurry return pipe, and the specific gravity measuring device (29)
) If the specific gravity is not the set specific gravity, the replenishment slurry is returned to the mixing tank (20) by switching the solenoid valve (22).

(34) is a control device which controls all the blending operations such as sequentially supplying each of the slurry component materials to the blending tank (20) and adjusting the composition, as well as issuing an alarm in the event of a malfunction and controlling during blending. This is responsible for stopping the slurry replenishment operation.

Next, the operation of blending replenishment slurry by the automatic replenishment slurry blending apparatus having the above configuration will be described with reference to the time chart shown in FIG.

When the liquid level in the mixing tank (20) reaches the set lower limit, the control device (34) is activated in response to a signal from the liquid level control device (21), and the automatic mixing cycle is turned on. The solenoid valve (22) is locked OFF. Then, the stirring tool (35) stops rotating and pure water is injected to the set level by opening the solenoid valve (28a). Next, a 10% aqueous solution of PVA was applied to a gear pump (
25), it is added to a set level in the same way as pure water via a solenoid valve (28b).

After adding this 10% aqueous solution of PVA, the preparation tank (20%
) starts rotating. Next, the phosphor (28) is supplied from the quantitative supply device (27) at the specific gravity value preset in the specific gravity measuring device (29).
Input until it reaches 1.495. This phosphor (28)
Supply is performed at high speed at first, and near the end point, operation is performed at slow speed to improve measurement accuracy.

When the addition of the phosphor (28) is completed, various additives are sequentially pumped into the metering pump (3) from each main tank (not shown).
The feed is added via the operations 0a) to (30c). In this example, a 10% aqueous solution of PVA, a surfactant solution, and finally ethylene glycol are added in the proportions shown in Table 1. These series of operation commands are sent to the system control device (3
4) is carried out by sequencer control.

Table 1 Order Material Amount 1, Pure water 11.6412, P
VA 4.5013, Phosphor
12.49Kg4, Sodium dichromate
270cc5, surfactant 250cc8,
Ethylene glycol 450ccIn order to improve the accuracy of each of the above metering pumps (30a) to (30c),
To prevent the liquid level height of the main tank of each material from changing,
For example, a form such as overflowing to a sub tank is adopted.

Furthermore, after the addition of these additives is completed, the specific gravity is checked at each step, so if there is an abnormality, a warning is issued.

Then, in the final specific gravity check after the final addition of ethylene glycol, if 1.480±0.005 passes, the solenoid valve (22) will be unlocked, the liquid level detection will also be turned on, and the system will return to normal mode. Returns and completes one cycle of automatic compounding.

The above example describes the green phosphor slurry that is the first color of an automatic coating line for multiple types of color picture tubes of 20 to 28 inches, but it can be similarly applied to blue as the second color and red as the third color. .

Moreover, it is particularly effective for coating not only color picture tubes but also cathode ray tubes for displays, especially phosphor slurries that are subject to aging problems.

Furthermore, the input and addition form of each material described in the above examples,
There are various combinations of blending amounts depending on the accuracy of the device and production conditions, and a mechanism for detecting malfunctions can be used that constantly checks not only the specific gravity but also the liquid amount itself.

Furthermore, in order to minimize addition by metering, materials that can be mixed in advance can be mixed in advance at a set addition ratio and then supplied to the mixing tank (20).

[Effects of the Invention] As described above, according to the present invention, the process of blending replenishment slurry in the phosphor slurry coating work is completely automated, and the automatic blending device is incorporated into the phosphor slurry coating line itself. By doing so, it is possible to save labor and improve the efficiency of the compounding process, and to greatly improve the production efficiency of phosphor products. Furthermore, since the slurry can be prepared in any amount, it is possible to eliminate fluctuations in slurry properties over time, increase the yield of the manufacturing process, and improve the quality of the product.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the main parts of an apparatus for explaining an embodiment of the present invention, FIG. 2 is a time chart of blending, and FIG. 3 is a main part of the apparatus for explaining the phosphor slurry coating process. FIG. 4 is a flowchart of the slurry preparation process. (1)...Phosphor slurry for injection, (2)...Glass panel, (10)...Replenishment tank, (11)...
Replenishment slurry, (20)...Blending tank, (22)...
... Solenoid valve, (27) ... Fluorescent substance quantitative supply device, (2
8)...Fluorescent material, (29)...Specific gravity meter, (30
a) ~ (30C)...metering pump, (34)...
Control device. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) After injecting and coating the inner surface of the glass panel with the phosphor slurry, the glass panel is rotated at high speed to shake off and collect the excess of the phosphor slurry. In a phosphor slurry coating method using an automatic phosphor screen coating device configured to automatically replenish an amount of replenishment slurry corresponding to the amount of consumed phosphor slurry, An automatic replenishment slurry mixing device is installed, and at least two of polyvinyl alcohol solution, ammonium dichromate, pure water, surfactant solution, and ethylene glycol are individually added to the phosphor using the automatic mixing device. A method for applying a phosphor slurry, which comprises adding and blending to obtain the replenishment slurry. (2) A method for applying phosphor slurry according to claim 1, characterized in that a device for continuously measuring the specific gravity of the replenishment slurry is provided to automatically control the amount of phosphor supplied. .