KR20010067848A - A New Apparatus and Processes using Electrical Field Dispenser - Google Patents

Abstract

PURPOSE: Fluorescent material coating apparatus and process using a field applying injection device are provided to broaden a coating area of a fluorescent material which is injected between partition walls. CONSTITUTION: An electric field is applied to a fluorescent material(4) by mixing a charge agent(surface active agent) with the fluorescent material(4) and electrifying the same, so that the fluorescent material(4) is electrified with (+) or (-) and a panel(address electrode)(2) is electrified with (+) or (-). The fluorescent material(4) is injected between partition walls(5). The fluorescent material(4) is coated by using an injection device(7). And, ultrasonic waves are irradiated to generate a wave motion artificially. Accordingly, the coating area of the fluorescent material(4) is broadened toward the upper portions of the partition walls(5).

Description

A New Apparatus and Processes Using Electrical Field Dispenser}

Phosphors in plasma displays are an important part of emitting light directly. The most common method for applying this phosphor is screen printing. However, the screen printing method is difficult to precisely control because the paste is used, and it is difficult to expect a high yield at the manufacturing stage due to a defect that is applied to an unwanted portion. As a result, the defect rate is high, which is a major reason for increasing the unit price of the plasma display. In addition, a dispenser using a nozzle has been recently reported, but the nozzle is made of steel, and thus, since the static electricity is generated between the surface of the phosphor and the nozzle when the phosphor is injected, the phosphor is not accurately and stably injected between the partition walls. This is not true. And to overcome this disadvantage, there is a way to ground the panel or just apply an electric field to the panel. However, this method also uses only the static electricity of the phosphor, so it is difficult to apply the phosphor accurately. There is a method of using an inkjet head, but since the partitions of the plasma display are very narrow, phosphors are not easily injected between the partition walls due to the problem of the viscosity of the inkjet head and the phosphor paste. There is a method of grounding the substrate and using only static electricity of the phosphor and a method of applying an electric field to the substrate, but since the electric field is not directly applied to the phosphor as in the present invention, the electric field between the phosphor and the panel having the address electrode is weak and stable. It is difficult to apply.

In order to stabilize the phosphor and widen the coating area between the partition walls, an electric field is directly applied to the phosphor or between the chamber containing the phosphor and the address electrode of the panel, or a charging agent is mixed with the phosphor to charge the phosphor and an electric field is applied to the address electrode of the panel. After the phosphor is stably injected between the partition walls, ultrasonic waves are irradiated artificially to generate appropriate waves to widen the coating area of the phosphor injected between the partition walls.

1 is a schematic diagram of applying a phosphor between partition walls using an injection device while applying an electric field in the present invention.

Figure 2 is a process flow chart showing the sequence of the overall process in the present invention.

Figure 3 is a schematic diagram showing the flow of the process in the present invention.

[Explanation of symbols on the main parts of the drawings]

1 Glass substrate 7 Injector

2: address electrode 8: agitator

3: dielectric 9: electric field applying device

4: phosphor 10: conveyor belt

5: bulkhead 11: ultrasonic generator

6: distance sensor

In order to form a phosphor film on the partitioned panel as shown in FIG. 1, first, the injector selects a certain amount of the phosphor and applies a force while continuously mixing the liquid phosphor with a stirrer and partitions along one nozzle connected in parallel. Is injected in between. In general, the nozzle may be made of glass, metal, and a metal containing glass, a conductive polymer, or ceramics. At this time, the nozzle is stationary and the phosphor can be applied between the partition walls as the panel moves along the conveyor belt. Then, in the same manner, a dispenser consisting of nozzles by different injectors continuously applies different colored phosphors. In this way, red, green, and blue phosphors are applied (including injecting three primary colors at the same time). In addition, ultrasonic waves are irradiated to widen the application area of the liquid phosphor applied between the partition walls to artificially form waves in the liquid phosphor to be applied to the upper end of the partition walls. Then, the drying process is completed, and finally, the coating of the phosphor is completed by the firing process. Because this method uses a very small nozzle, it can also be applied stably between small partitions, freeing the phosphor from overflowing into the next cell or surprise over the bulkhead, as in screen printing technology. And since the nozzle is located at a certain distance from the bulkhead by attaching the distance sensor to the lower part of the nozzle or the spray device, the phosphor is smoothly injected between the bulkheads, and the liquid phosphor is selectively injected by applying the phosphor of the correct quantity using the spray device. You can do it. In addition, after injecting the liquid phosphor, ultrasonic waves are applied to the panel to improve the coating area of the phosphor. The phosphors are charged by the polarity of the phosphor and the panel when the phosphors are injected between the partition walls by charging the panels (address electrodes) with opposite polarities using a charging agent (surfactant) or an electric field, respectively. Figure 2 is a flow chart showing the sequence of the phosphor manufacturing process using the injector devised in the present invention. Figure 3 is also a simplified illustration showing the process content using the injector in the present invention.

The use of a very small nozzle allows the injection of a stable and accurate dose of phosphor between the bulkheads. Therefore, it is possible to prevent the overflow of the phosphor occurring in the existing screen printing can be completely free from defects in manufacturing. In addition, it is applied to the phosphor and the panel (address electrode) by using a charging agent (surfactant) or an electric field application method to inject the phosphor, and a distance sensor is attached to the lower end of the nozzle or the injection device so that the nozzle is always located between the partition walls. It is possible to stably inject between the partition walls by preventing static electricity caused by the friction of the phosphor and the nozzle generated by the dispenser method. This is completely free from defects of the phosphor, thereby improving the yield of the panel and obtaining high added value. In addition, after the liquid phosphor is stably coated, ultrasonic waves may be irradiated onto the panel to increase the coating area of the phosphor, thereby improving the brightness of the plasma display (PDP). Therefore, it is a great effect of the present invention that the high value added can be improved by improving the quality of the plasma display and reducing defects caused by phosphors.

Claims (3)

A method of injecting a phosphor by applying an electric field to the phosphor to charge the phosphor with (+) or (-) and the panel (address electrode) with (+) or (-). Method of spreading the coating area by coating the phosphor using an injection device and then irradiating ultrasonic waves to artificially generate waves to apply the phosphor to the upper part of the partition wall. A method of charging by mixing a charging agent (surfactant) to the phosphor by applying an electric field to the phosphor.