JPS59105240A - Application device of liquid for forming phosphor screen - Google Patents

Abstract

PURPOSE:To improve quality and an yield in the manufacturing process while removing application unevenness by electrically measuring a circulating flow of liquid by means of a measuring device and reading as well as operating its value in order to put out the prescribed control signal. CONSTITUTION:Phosphor slurry 2 sent from a slurry tank goes through a measuring tube 40 having a flow measuring mechanism by a pipe hose 8 while being circulated to an original tank through an electromagnetic valve. The slurry 2 pushes up a core 41, which changes its position according to its flow, up to the position able to be balanced. The Q value of a coil 42 set outside of a measuring tube changes according to the position of said core, while said value is read and undergoes digital conversion as well as operation treatment by a control device 43 so that a result of measurement may be displayed by an indicator 47. Further, the number of revolution can be automatically changed as well as a circulating flow of the slurry 2 can be controlled by sending a control signal from the control device 43.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for applying a liquid material, such as a phosphor slurry, used for forming a phosphor surface.

Generally, the phosphor surface of a color picture tube is prepared by coating the inner surface of a glass panel with a phosphor slurry in which a certain phosphor is suspended in a solution containing a photosensitive binder, such as polyvinyl alcohol and ammonium dichromate. After drying, a latent image is formed by exposure through a shadow mask as a color selection electrode using an exposure device, and then developed to form a phosphor stripe or dot of a predetermined size at a desired position. (hereinafter collectively referred to as phosphor stripes).

6g of green, blue, and red! The phosphor slurry was used to form six types of phosphor stripes at positions corresponding to the apertures of the shadow mask.

Since the phosphor slurry used for forming the phosphor surface is expensive, the excess amount in the coating process is recovered, all necessary compositional adjustments are made, and the slurry is used again as a slurry for forming the phosphor surface. The flow of supplying and recovering this phosphor slurry is shown in FIG.

In Figure 1, (1) is a slurry tank for injection with a pump mechanism at the bottom, (2) is a fluorescent slurry, and (3) is a slurry tank for injection.
(4) is the glass panel (3).
Collection container for shaking off and collecting by high-speed rotation of (
5) is a liquid level control device for keeping the liquid level of the injection slurry tank (1) constant, and (6) is the injection slurry tank (1).
The phosphor slurry in 1) (2) is refilled in the replenishment slurry tank, and (7) is the phosphor slurry in the replenishment slurry tank (6)! This is a pump for circulating J-no.

In such threads, the phosphor slurry (2) is pumped into the lower pump (snake pump) of the injection slurry tank [1].
The flow flows out through the hose (8) and the glass spring /L/(
3), the slurry flows continuously through the N circulation system which returns to the slurry tank (1) for injection via the electromagnetic valve (9) for injecting the slurry. On the other hand, the extra phosphor sura once injected! I-(2) returns to the injection slurry tank (1) via the collector (4). The decrease in the phosphor slurry IJ -Fi+ due to repetition of this coating process is replaced by another replenishment slurry!J -Tl0I which is circulated to the pump (γ) in another replenishment slurry tank (6). , liquid level control device (
5), this is supplemented by automatically and dynamically replenishing the injection slurry tank (1) via the replenishment solenoid valve (11).

Normally, color picture tube fluorescent surfaces are manufactured by an automatic machine that sequentially moves a carrier on which a glass panel is fixed to the above-mentioned manufacturing process lined in a loop at a predetermined cycle time. To apply the phosphor slurry in the phosphor screen coating process, hold the glass spring /I/(3) in the carrier as shown in Figure 2(a), rotate the carrier 4, and press the The phosphor slurry is activated using a solenoid valve (9) that is opened and closed by a timer connected to the circulatory system.
J-f21 at the specified position on the panel (3) with the nozzle /1/(
When injected for a predetermined period of time from (c), the phosphor slaly IJ - (2
1 spreads over the inner surface of the glass spring /L/(3) to form a uniform coating surface.

In this case, by appropriately selecting the amount of slurry (2) to be injected, the inclination of the carrier (c), and the rotation speed, the phosphor slurry (2) can be applied to the entire surface of the glass panel (3) except for the inner skirt. spread. After applying the phosphor slurry (2) in this way, the excess slurry is shaken off and collected by high-speed rotation, and the phosphor slurry (2) applied to the glass panel (3) is made into a predetermined film thickness as described above. If the process is carried out sequentially, the glass panel (3
) has Fi green, blue, and red phosphor stripes (20
), (21) and (a) are formed.

However, according to the conventional method described above, coating unevenness as shown in FIG. 6 may occur in the phosphor slurry film. That is, when injecting the phosphor slurry (2) into the glass spring 1v (8), if the amount injected is too large, the slurry will have wrinkles during the slurry application process, resulting in wrinkles cIυ as shown in FIG. 6(a). .

On the other hand, if the injection amount is small, the slurry film will not spread over the entire surface and will form an uncoated portion 0→ as shown in FIG. 6(b). These coating irregularities have the major disadvantage of lowering the yield of the slurry coating phosphor surface forming process and lowering the quality of the phosphor surface. Particularly when the slurry coating process is completely automated, once such coating unevenness occurs, it tends to occur continuously, which is a problem.

Therefore, an object of the present invention is to provide a novel coating device for eliminating the coating unevenness and improving the quality and yield of the manufacturing process.

It is clear that the coating unevenness is caused by fluctuations in the amount of circulation of the phosphor slurry. Further reasons for this include fluctuations in the specific gravity and viscosity of the phosphor slurry over time, as well as the mesh that is set in the injection nozzle (V) to remove dust and aggregated particles from the phosphor slurry. It can be clogged.

Among these causes, fluctuations in specific gravity are relatively easy to control, but some fluctuations in viscosity and clogging of the mesh are difficult to completely control and require periodic inspection. ing.

The inventor paid attention to this point, and as a result of examining and experimenting with a method of automatically measuring and displaying the G circulation flow rate and controlling the flow rate by feeding back the output signal, the inventor found that an electrical The present invention was completed by a method of measuring the flow rate. An embodiment of the present invention will be explained in detail below with reference to FIG. The phosphor slurry (2) sent from the slurry tank for injection passes through a measuring tube with a flow rate measuring mechanism shown in FIG. (see) and returned to the original injection slurry tank.

The measurement of the flow rate is carried out by an electrical method as described above, in which a solenoid valve (9) is automatically opened and closed.

In other words, when a signal is sent to the injection solenoid valve (9), the flow rate measuring device! 11-i Immediately measure the flow rate according to the following principle. The injection slurry (2) pushes up the core GI whose position changes depending on its flow rate to a balanced position, and the Q of the carp /L/(b) set outside the measuring tube depends on the position of the core Oυ. The value changes, and the value is instantaneously read by the control device.The core ←υ is equipped with a floating blade (b) that is made as small as possible, and a hole is inserted in the center of the core ←υ. It is supported by upper and lower stoppers).

Further, the control device has a built-in microcomputer for processing and making judgments on the measurement results. The reason why the above-mentioned measurement is performed when the solenoid valve is operating is because the flow rate changes depending on the resistance of the entire system, so the measurement is performed in synchronization with the actual injection of slurry. The measurement results are displayed on the display, allowing manufacturing line management patrollers to judge whether the flow rate is appropriate or not without actually measuring it. Depending on the measurement results, if necessary, it is also possible to activate a blind alarm or a 5-report lamp. Furthermore, if the drive source of the injection slurry tank II) is a Do motor, the rotation speed is automatically changed by sending a control signal from the control device to control the circulating flow rate of the fluorescent slurry (2). It is also possible.

In the above embodiments, the case of applying a phosphor slurry has been described, but this invention is also applicable to other systems that require flow rate adjustment.
It can also be used, for example, to measure and adjust the amount of inflow of filming lacquer in the manufacturing process of phosphor screens. Furthermore, the operating functions explained in FIG. be.

As described above, according to the coating apparatus of the present invention, the flow rate of the circulating liquid can be managed and controlled reliably, thereby improving the quality of the coating film and the manufacturing yield.

Furthermore, the apparatus of the present invention is suitable for automated lines, and cost reduction is also achieved.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the circulation system of the fluorescent slurry, Figures 2 (!L) and (b) are explanatory diagrams of the coating process of the fluorescent slurry, and Figures 6 (a) and (b) are FIG. 4, which is a diagram showing how uneven coating occurs, is a schematic sectional view of a main part of an embodiment of the coating apparatus of the present invention. (1)... Slurry tank for injection, (2)... Fluorescent slurry, 13)・1. Crow panel, (8)...
Hose, (9)...TI, +6 Valve, (c)...
Nozzle, -...Flow rate measuring tube, ←υ...Core, Glossy
・Coil, (c)...control device. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Shin Kuzuno (1 other person)

Claims (4)

[Claims] (1) A tank containing a liquid substance used for forming a fluorescent surface, an injection means for injecting and applying the liquid substance in this tank to the inner surface of the glass panel, and a circulation system that circulates the liquid substance and returns it to the tank. means, a flow rate measuring device that pneumatically measures the circulating flow rate of the liquid, and a control device that reads the value measured by the flow rate measuring device, performs calculations, and outputs a predetermined control signal. A coating device for a liquid material for forming a fluorescent surface, characterized in that: (2) The apparatus for applying a liquid material for forming a fluorescent surface according to claim 1, wherein the circulating flow and amount of the liquid material are controlled by the control signal. (3) The apparatus for applying a liquid material for forming a fluorescent surface according to claim 1, wherein the flow rate is displayed on a display. (4) The apparatus for applying a liquid material for forming a fluorescent surface according to claim 1, wherein the flow rate measuring device measures the flow rate in synchronization with the injection start operation of the injection means.