JP2001357780A - Manufacturing method and manufacturing device of plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of unevenness in the fluorescent substance or a plasma display panel wherein a fluorescent substance solution is jetted from the nozzles and coated on a substrate panel in a manufacturing method. SOLUTION: Unevenness of a fluorescent substance on a substrate panel is prevented by arranging plural nozzles equipped with adjustable flow passage in a route in which the fluorescent solution is ejectable, by ejecting a gas in a desired direction from surroundings of an ejecting port, and by guiding the fluorescent solution ejected from the nozzle by the discharged gas.

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 color plasma display or a striped black matrix type color picture tube used as a wall-mounted television or a display for displaying information.

[0002]

2. Description of the Related Art On a back plate of an AC type plasma display, a number of elongated strip-shaped recesses surrounded by ribs and a bottom surface of a substrate are provided side by side, and each recess has a fluorescent light of three colors of red, green and blue. It is necessary to form a body membrane. Generally, screen printing is used as a method of forming the phosphor. In this method, a phosphor liquid in which phosphor fine particles are dispersed in a solvent is poured through a squeegee mask adapted to each color into the entire concave portion of the back plate. In this method, the color mixture occurs due to the mechanical deformation of the squeegee, so a skilled worker is required. Also, the shape of the phosphor film formed on each rib portion is planar, and the phosphor adheres on the convex portion. Another problem is that it is difficult to manufacture a high-definition panel or a large-sized panel in which the interval between the concave portions is small.

As another method of forming a phosphor, Japanese Patent Laid-Open No.
The invention described in Japanese Patent Publication No. 204032 is known. In this method, a nozzle is positioned on a substrate panel, and moves relatively at a speed of about 0.5 m / sec to 3 m / sec along a concave portion of the substrate panel while discharging a phosphor liquid from the nozzle. Thereafter, the liquid crystal is moved in the vertical direction according to the number of discharge ports, and is again moved along the concave portion of the substrate panel, so that the inside of the concave portion of the entire panel is filled with the phosphor liquid. After that, the formation of the phosphor is completed by the drying and baking steps. The size of the discharge port of the coating head requires a circular diameter smaller than this, since the phosphor liquid is introduced directly into the recess. The discharge amount and the speed are determined so that the phosphor liquid fills 100% of the concave portion. By using this method, a free-form phosphor film can be manufactured without color mixing and without the need for a skilled person, and can be used for large-sized panels and high-definition panels.

[0004]

However, in the conventional method, the amount of phosphor in the recess after application is different due to the different discharge amount of each nozzle of the coating head having a plurality of nozzles. As a result, the completed plasma display is turned on. Occasionally, vertical streak-like unevenness occurs in which the luminance of each concave portion is different. This is because the brightness is regularly repeated according to the number of nozzles installed in the coating head 1. In addition, the phosphor discharge from the nozzle causes the phosphor liquid to climb onto the convex part, and the phosphor in the concave part causes the symmetry of the right and left sides to deteriorate, so that the oblique view from the slant It becomes uneven.

FIG. 3 shows a conventional head. Coating head 1
The nozzle 2 is manufactured by making a hole of the nozzle 2 in a metal on the lower surface of the coating head 1 by an electric discharge machine or by pressing a metal pipe into a hole previously formed in the coating head. The hole from which the liquid is discharged is circular and has a diameter A = 0.016.
The nozzle 2 having the same hole diameter is manufactured with high accuracy within a diameter error of ± 0.0005 mm in mm. However, the coating head 1
When the discharge amount between the nozzles 2 is measured, there is a variation of 5% in the discharge amount. This is because the discharge amount is proportional to the fourth power of the discharge port diameter, so that the diameter error of the discharge hole ± 0.0005.
mm, a 5% difference in the discharge amount occurs. For this reason, the diameter error of the discharge hole may be set to ± 0.0005 mm or less, but it is impossible even with the latest state-of-the-art micro electric discharge machining technology. When the size of the hole is large, the ratio of the diameter error to the diameter A of the hole is also small, and the variation in the discharge amount can be suppressed. However, since the discharge hole having a diameter smaller than the size of the concave portion for introducing the phosphor liquid is required. In addition, variations in the discharge amount cannot be suppressed. For this reason, when a panel is manufactured with this coating head, bright and dark vertical streak-like unevenness (unevenness of the difference in discharge amount) occurs when the plasma display panel is turned on, according to the number of nozzles.

[0006]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a plurality of nozzles in which a plurality of nozzles each having an adjustable flow path resistor are disposed in a discharge path capable of discharging a phosphor liquid. And applying a uniform amount of the phosphor liquid to the concave portion of the plasma display panel substrate.

[0007]

1 and 2 show an embodiment of the present invention.

(Embodiment 1) FIG. 1 shows a cross section of a phosphor coating head. In FIG. 1, 1 is a coating head, 10 is an adjusting screw, and 11 is a discharge path. The ejection amount is adjusted by inserting and removing the adjusting screw 7 into and from the ejection path 6 of the coating head 1 configured as described above. While discharging the phosphor liquid from the coating head 1 at a fixed rate, each nozzle 2
Measure the amount of discharge from, adjust each screw, and adjust the discharge amount.

The flow path resistor is not limited to the adjusting screw 10, but may be any as long as it changes the flow path resistance of the discharge path 11. Furthermore, the flow path resistance may be changed by changing the shape, inner surface roughness, material, and the like of the discharge path. Further, the discharge amount may be adjusted by controlling the pressure, temperature, discharge time, and the like of the phosphor liquid supplied to each nozzle.

(Embodiment 2) FIG. 2 shows a cross section of a phosphor coating head. 2 is the same as Embodiment 1 except that a gas guide 22 is provided around the coating head 1 in FIG. The gas is released from the outside of the discharge port of the nozzle 2 of the first embodiment to correct the bending of the discharge of the phosphor liquid.
The gas flows from the gas supply pipe 21 to the outside of the coating head 1, and the gas discharge port 20 located near each nozzle 2 discharge port.
Released from The discharged phosphor liquid is discharged to the center of the concave portion of the substrate along the flow of the discharged gas. The gas may be industrial air, nitrogen or the like, but it is necessary to pass through a filter to remove dust and the like. The flow rate of the gas is preferably equal to or slightly higher than the velocity of the liquid to be discharged. Actually, the discharge liquid speed is set to 1 m / sec to 2.5 m / sec while 1 m / sec to 2 m / sec.

The conditions for producing a panel using the nozzle of the present invention are as follows.

The phosphor liquid used in this case had a weight ratio of resin: phosphor: solvent = 1: 7: 2. As the phosphor, red (Y, Gd) BO ₃ : Eu, green BaAl ₁₂ O
₁₉ , three types of blue 3 (Ba, Mg) O.8Al ₂ O ₃ were used separately, but other types may be used as long as the phosphor has a particle size of about 3 μm or less. The solvent used was BCA, the resin was an acrylic resin, and the inner width of the rib was 200 μm to 300 μm. The solvent may have a high boiling point and can dissolve the resin. For example, diethylene glycol ethyl ether, dipropylene glycol monomethyl ether,
Carbitol acetate ethylene glycol acetate and the like. Various polymers such as alkylated cellulose can be used as the resin. The nozzle used was a metal having a hole diameter of 0.160 mm and 5 holes. The interval between the irregularities is 3
1.08mm in color, nozzle movement pitch 1.08m
m × 5 = 5.40 mm. The panel is about 2.8 thick
mm, made of low melting point glass and opaque to ultraviolet light. A convex portion is formed in a line on one surface of the glass. The number of irregularities is 852 × 3 (3 colors) = 255
The size is about 1000 mm × about 700 mm with six pieces. The height of the projection is about 0.120 mm. For contrast, the concave and convex portions are black. 3 colors (red,
Blue, green), and apply the phosphor solution at 100 ° C for 30 minutes.
After drying for 10 minutes, firing at 500 ° C. for 10 minutes completes the formation of the phosphor.

[0013]

As described above, according to the present invention, the phosphor liquid in which the phosphor fine particles are dispersed in the liquid medium is discharged from the plurality of nozzles onto the concave inner surface of the plurality of irregularities on the surface of the substrate,
In the method of forming a phosphor film by heat treatment, by using a coating head having a plurality of nozzles having the same phosphor liquid discharge amount, it becomes possible to eliminate the vertical streak unevenness that has occurred in the conventional nozzle.

In addition, in long-time use or intermittent use, discharge of the phosphor from the nozzle may bend. This is because, as shown in FIG. 4, large particles 3 such as agglomerates in the liquid stay in the plane portion of the discharge path inside the nozzle 2, or the phosphor liquid 4 discharged from each nozzle 2 attracts each other due to static electricity. Or to repel. As a result, as shown in FIG. 5, the phosphor in the concave portion becomes less symmetrical to the right and left, and when the plasma display panel is turned on, there is oblique unevenness when viewed from the slant in the direction of the arrow.
In such a case, the discharge of the phosphor liquid from the vicinity of the discharge port of the nozzle corrects the curvature of the discharged phosphor liquid, and the phosphor liquid is applied to the center of the substrate concave portion. As a result, there is no deflection of the phosphor in the concave portion, and when the plasma display panel is turned on, oblique unevenness when viewed from a slant in the direction of the arrow is eliminated.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a phosphor coating head according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a phosphor coating head according to a second embodiment of the present invention;

FIG. 3 is a sectional view showing a conventional phosphor coating head.

FIG. 4 is a sectional view showing precipitation of particles in a conventional phosphor coating head.

FIG. 5 is a conceptual cross-sectional view of a substrate having oblique unevenness.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coating head 2 Nozzle 4 Phosphor liquid 10 Adjustment screw (flow path resistor) 11 Discharge path 21 Gas discharge port

Continued on the front page (72) Inventor Naoko Matsuda 1006 Kadoma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. Nobuyuki Kirihara 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 5C028 FF16 5C040 FA01 FA02 GG09 JA13 MA02 MA23 MA24

Claims (5)

[Claims] 1. A substrate liquid and a coating head are relatively moved from above vertically into a plurality of juxtaposed linear recesses provided on a surface of a substrate, the phosphor liquid having phosphor fine particles dispersed in a liquid medium. And applying a phosphor liquid to the substantially concave portion to form a phosphor film, wherein the coating head has a plurality of nozzles, and a discharge amount of the phosphor liquid discharged from the nozzles is arbitrarily determined. A method for manufacturing a plasma display panel, which is individually adjustable. 2. The plasma display panel manufacturing method according to claim 1, wherein the phosphor discharge amount is adjusted by changing a flow path resistance of a phosphor discharge passage of the nozzle. 3. A substrate liquid and a coating head are relatively moved from above vertically into a plurality of substantially straight concave portions provided on a surface of a substrate, the phosphor liquid having phosphor fine particles dispersed in a liquid medium. Causing the phosphor liquid to be discharged into the substantially concave portion to form a phosphor film, wherein a gas is discharged in a desired direction from around a discharge port of the nozzle, and the phosphor liquid is discharged from the nozzle. By using said gas. 4. A substrate having a plurality of parallel substantially concave portions provided on a surface thereof, an application head having a nozzle capable of discharging a phosphor liquid, a mounting table for mounting the substrate, and the mounting table. In a plasma display panel manufacturing apparatus including a mounting table driving unit for driving a table and a head driving unit for driving the coating head, an adjustable flow path resistor is arranged in a discharge path formed in the nozzle. A plasma display panel manufacturing apparatus characterized by the following. 5. A substrate having a plurality of side-by-side substantially concave portions provided on a surface thereof, an application head having a nozzle capable of discharging a phosphor liquid, a mounting table for mounting the substrate, and the mounting table. In a plasma display panel manufacturing apparatus including a mounting table driving unit for driving a table and a head driving unit for driving the coating head, a gas discharge port capable of discharging gas is provided around a discharge port of the nozzle. Characteristic plasma display panel manufacturing equipment.