JP2000251702A - Forming method for phosphor screen of plasma display panel(pdp) - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a phosphor screen on a back surface plate of a plasma display panel(PDP). SOLUTION: A phosphor paste 7 is filled in recessed parts 9 separated by ribs 8, by delivering the phosphor paste from an orifice of a phosphor layer forming device. Then, drying and baking are performed, and then, evry substance excepting the phosphor is removed to form the phosphor layer on a plasma display panel(PDP). When the phosphor paste 7 is filled in the recessed parts 9, high voltage pulse is applied to the phosphor layer forming device. Thereby, the pattern of the phosphor paste is controlled and a filling is stably performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a phosphor screen of a back plate for a plasma display panel, and more particularly to a method of discharging a phosphor paste made of a high-viscosity material of 1000 cps to 1,000,000 cps, and applying the paste to a predetermined surface of the back plate. The present invention relates to a method for forming a phosphor screen in which phosphor layers are embedded between ribs at positions and subjected to a drying heat treatment as necessary to form phosphor layers between the ribs or on the side surfaces of the ribs.

[0002]

2. Description of the Related Art In recent years, plasma display panels (hereinafter, also referred to as PDPs) have been developed for various display devices because of their small thickness, light weight, clear display, and wide viewing angle compared with liquid crystal panels. It is used for

In general, a PDP has a structure in which a pair of regularly arranged electrodes are provided on two opposing glass substrates, and a gas mainly composed of neon, xenon, or the like is sealed between the electrodes. Then, a voltage is applied between these electrodes, and a discharge is generated in minute cells around the electrodes, so that each cell emits light to display.
Here, the configuration of the PDP will be described using an example of an AC PDP shown in FIG.

FIG. 12 is a perspective view of the structure, but for simplicity, the front plate (glass substrate 610) and the back plate (glass substrate 620) are shown apart from the actual state.

As shown in FIG. 12, two glass substrates 6
10 and 620 are arranged in parallel and opposed to each other, and both are held at a predetermined interval by a partition (rib) 630 provided in parallel on a glass substrate 620 serving as a back plate.

A composite electrode composed of a transparent electrode 640 serving as a sustain electrode and a metal electrode 650 serving as a bus electrode is formed in parallel on the back plate side of the glass substrate 610 serving as a front plate, and covers the same. Thus, a dielectric layer 660 is formed, and a protective layer (MgO layer) 670 is further formed thereon.

A partition 630 is provided on the front plate side of the glass substrate 620 serving as a back plate so as to be perpendicular to the composite electrode.
Address electrodes 680 are formed in parallel with each other, and a fluorescent screen 690 is provided so as to cover the side surface of the partition 630 and the cell bottom surface.

The partition 630 defines a discharge space.
Each partitioned discharge space is called a cell or a unit light emitting region.

The AC type PDP is of a surface discharge type, and has a structure in which an AC voltage is applied between composite electrodes on the front panel to discharge. In this case, since the alternating current is applied, the direction of the electric field changes according to the frequency. Then, the phosphor 690 is caused to emit light by the ultraviolet rays generated by the discharge, and the light passing through the front plate can be visually recognized by an observer.

[0010]

A screen printing method is often used for forming a phosphor layer in the production of such a PDP. However, in the screen printing method, the shape of the screen plate changes or wears out during repeated printing, so that the manufacturing cost increases, and since the screen printing method cannot perform high-precision printing,
It cannot be used for forming a phosphor layer of a panel having a large size or a high definition pattern.

As another method for forming the phosphor layer, there is a method using a photolithography method. In the photolithography method, it is difficult to surely form the phosphor layer with good adhesion on all the side surfaces of the partition walls and all the bottom portions between the partition walls.

[0012] As shown in FIG.
In some cases, a space 351 may be generated at a corner of the bottom 315A between the partition walls 13 on the partition side, or a gap 352 may be formed along the side surface 313A of the partition 313.

In FIG. 11, reference numeral 311 denotes a glass substrate;
12 is an electrode, 313 is a partition, 313A is a side, 314R
Is an R (red) phosphor layer, 314G is a G (green) phosphor layer, 314B is a B (blue) phosphor layer, 315 is a dielectric layer, and 315A is a bottom.

In this method, in order to form red, green, and blue phosphor layers, it is necessary to repeat the steps of applying, exposing, developing, and drying a phosphor paste layer for each color. There is a problem that the cost is increased because unnecessary portions of the phosphor are discarded for each color.

A method of forming a phosphor layer by an ink jet method has also been proposed. Here, as the inkjet method, a method of extruding the ink by heating a part of the container containing the ink and generating bubbles, and a method of extruding the ink by the pressure by vibrating the piezoelectric ceramic are known. However, in any case, the force for pushing out the ink is weak, and only a liquid having a viscosity of 20 cps or less can be ejected. In addition, since the diameter of the orifice is small, when an attempt is made to discharge a liquid containing particles such as phosphors,
There is a problem that causes clogging. Further, the diameter of the ejected ink is several times larger than the diameter of the orifice. Therefore, if the diameter of the orifice is large, high-definition patterning cannot be performed.

As another method for forming the phosphor layer, a method using a dispenser has been proposed. The dispenser method is a method in which a phosphor paste is accommodated in a container having a hole on a nozzle or a needle, and the phosphor paste is extruded by applying pressure to the container to discharge the paste.

In the case of the dispenser method, it is necessary to precisely control the distance between the tip of the nozzle or the needle and the substrate, and to detect subtle warpage or unevenness of the substrate and to adjust the distance to the substrate accordingly. It is necessary to provide a mechanism that makes it constant. When at least several hundred or more phosphor layers are formed as in a PDP, it is necessary to arrange a number of nozzles or needles, and apply and form them simultaneously. Is complicated, and there is a problem that the apparatus cost increases.

In the dispenser method, the outer diameter of the phosphor paste to be discharged is at least larger than the inner diameter of the nozzle or the needle. Needs to be smaller. Arranging a large number of nozzles or needles having such a small hole diameter increases the cost of the apparatus, and causes problems such as clogging of the phosphor particles and abrasion of the orifice portion.

In order to manufacture a forming apparatus having a large number of orifices at a low cost, it is desirable to use a structure having a large number of holes formed in the bottom surface of the container. When applying pressure to such a discharge unit to discharge the phosphor paste, the discharge direction is not determined, and the discharge cannot be performed with high accuracy.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a method for forming a phosphor screen of a PDP at low cost and with high precision.

[0021]

According to the present invention, there is provided a phosphor layer forming apparatus having a process for forming a concave portion on a substrate, which is partitioned by a rib, and a phosphor paste having an orifice therein. A step of forming a protruding phosphor paste meniscus, and applying a high voltage pulse to the phosphor layer forming apparatus to pull out and extend the meniscus, cutting and separating a part of the meniscus to form a phosphor paste in the recess. Forming a phosphor layer, and drying the phosphor paste layer to form a phosphor layer in the recess by removing components other than the phosphor in the phosphor paste layer. A method of forming a PDP phosphor screen, a step of forming a concave portion partitioned by ribs on a substrate, and a phosphor layer forming apparatus having an orifice and containing a phosphor paste therein. Pressurizing the paste to extrude the phosphor paste from the orifice, and applying a high-voltage pulse to the phosphor layer forming apparatus to control the shape of the phosphor paste extruded from the orifice so that the phosphor becomes smaller Reducing the diameter of the tip portion of the body paste, and drying the phosphor paste layer, forming a phosphor layer in the recess by removing components other than the phosphor in the phosphor paste layer, A method for forming a PDP phosphor screen, comprising:

Further, according to the method of forming a PDP phosphor screen of the present invention, the phosphor paste can be used as a phosphor paste at 1000 cps to 1000 cps.
By increasing the viscosity to 000 cps, after filling the phosphor paste between the ribs and then drying the solvent, the adhesion to the ribs is particularly improved, and the desired phosphor layer can be formed. Features.

Further, the method of forming a PDP phosphor screen according to the present invention is characterized in that the phosphor particles have an average particle size of 1 to 10 μm and the luminous efficiency of the phosphor is enhanced.

Further, according to the method of forming a PDP phosphor screen of the present invention, the discharge amount of the phosphor paste is controlled by the pressure and / or the voltage application condition applied to the container, and the coating speed is further controlled so that the phosphor of a desired thickness can be obtained. It is characterized by forming a body layer.

According to the present invention, by applying a high-voltage pulse, the tip of the discharged phosphor paste becomes thin, so that the phosphor paste can be discharged using a relatively large orifice diameter. Therefore, the phosphor paste can be stably filled without clogging or abrasion of the orifice by the phosphor. Also, PD with high definition pattern
A device that can be used for P and can simultaneously fill a large number of phosphor layers can be manufactured at low cost.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a PDP phosphor screen forming method according to the present invention will be described with reference to the drawings.

The phosphor paste shape by the high voltage pulse
Control FIG. 1 is a diagram for explaining a state of elongation of a meniscus by a high-voltage pulse, which is a feature of the embodiment of the PDP phosphor screen forming method of the present invention. FIG. 2 is a view for explaining an example of the relationship between the shape of the discharged phosphor paste and the voltage application condition. FIG. 3 is a diagram showing an example of an applied voltage condition.

FIG. 1 illustrates a case where a syringe type discharge unit is used.

In FIG. 1, a container 13 having an orifice 13a is filled with a phosphor paste 14, and a projection (meniscus) 17 of the phosphor paste is formed from the orifice 13a. The diameter of the orifice 13a,
Depending on various conditions such as the viscosity of the phosphor paste, the meniscus 1
In the case where it is difficult to form 7, the formation of a meniscus may be promoted by applying pressure to the phosphor paste 14.

In this state, when a high voltage pulse is applied to an electrode (not shown), the meniscus 17 is gradually pulled out,
An extension 18 is formed. As the high voltage pulse applied at this time, as shown in FIG. 3, a pulse to which a rectangular voltage is repeatedly applied is preferably used. The waveform of the pulse voltage is not limited to a rectangular wave, and the extended portion can be similarly formed by using a waveform such as a sine wave or a triangular wave. The offset position of the voltage is 0 V
A voltage such as −5 kV may be applied so that the discharge unit side is positive (FIG. 3A), or −2.5 kV to 2.5 kV.
Voltages of both polarities may be applied alternately, such as kV (FIG. 3B), or may be applied such that the discharge section side becomes negative, such as -5 kV to 0 V, and a voltage having a predetermined amplitude value or more. If so, the meniscus 17 can be extended similarly regardless of the offset position.

The frequency of the pulse voltage is preferably higher, and if possible, it is desirable to use a high-frequency pulse voltage of 1 kHz or more. As the frequency became lower, it was difficult to form an elongated portion. At 10 Hz or less, no elongated portion was formed. When a DC voltage was applied, no discharge of the phosphor paste was observed even when the pressure was increased.

Next, the relationship between the applied voltage condition and the degree of extension of the meniscus 17 will be described. The voltage application conditions are shown below. Nozzle material: Teflon Orifice diameter (nozzle inner diameter): 270 μm Distance between orifice and base material: 750 μm Waveform: rectangular Frequency: 1 kHz Offset voltage: 0 V Back pressure: 3 atm Except for changing the amplitude voltage in the range of 2 kV to 15 kV In all cases, voltage was applied under the above conditions, and the orifice 13
The outer diameter of the phosphor paste at a position of 0.25 mm from a was measured using a CCD camera. FIG. 2 shows the measurement results.

As shown in FIG. 2, when the amplitude was larger than 3 kV, an elongated portion smaller than the orifice diameter was formed, and when the amplitude was smaller than 2 kV, no extension of the meniscus 17 was observed.

The voltage application condition is that the substrate 20 and the orifice 1
This is optimally set in accordance with the distance to 3a. If the amplitude voltage is too low, the diameter of the phosphor paste becomes large even near the substrate 20. If the diameter of the phosphor paste is larger than the diameter of the orifice 13a, inconveniences such as the top of the rib or the flow of the phosphor paste into an adjacent cell may occur. In addition, if the tip has a large diameter, the phosphor paste is difficult to separate, and the recess is not smoothly filled with the phosphor paste. If the amplitude is too large, the extension 18 of the phosphor paste becomes sufficiently thinner at a position higher than the top of the rib, and a part 19 is separated. The separated phosphor paste 19 scatters over a considerably wide range from the position separated by the influence of the electric field. Therefore, if the separation position is high, there is a problem that the separated paste adheres to the top of the scattered area rib or an adjacent cell. As described above, by adjusting the voltage application conditions to an appropriate range, the phosphor paste can be filled into the recess between the ribs with an appropriate diameter from the orifice having a relatively large opening.

Next, a case where the phosphor paste is extruded by pressure alone without applying a high-voltage pulse will be described as a comparative example with reference to FIG. FIG. 4 shows a case where the phosphor paste is formed on a flat substrate for simplicity.

In FIG. 4, a nozzle 22 is provided at the bottom of the dispenser container 21. Container 2
A phosphor paste 23 is accommodated in 1, and the phosphor is extruded by applying pressure by a pressing means (not shown), and a phosphor paste layer 24 is formed on the substrate 20. At this time, in order to perform stable ejection, the nozzle 2
It is necessary to precisely control the distance between the position 2 and the substrate 20. This distance needs to be set to an appropriate value depending on the rheological characteristics of the substance to be discharged, the discharge amount, and the moving speed. This is because, as shown in FIG.
This is because it is necessary to maintain a balanced state because the space between the lower portion and the substrate 20 is affected by the wettability and the surface tension of both the lower portion of the nozzle 22 and the substrate 20. For this reason, if the moving speed or the distance to the substrate 2a changes even a little, the balance is lost and the ejection becomes unstable.
When the phosphor paste is used, the substrate 20 and the nozzle 2
A suitable distance from 2 is in the range of 0.1 to 0.3 mm.
For example, when the distance from the substrate 20 is 0.2 mm,
It is necessary to control with a precision of about several μm in a range of several percent of 0.2 mm, and when using such a dispenser, it has a servo function of measuring the distance to the substrate and adjusting the distance. Is common.

When an attempt is made to form a phosphor paste layer on a PDP, such a servo mechanism is indispensable because there is a change in the height of the formed partition walls in addition to the normal warpage and undulation of the substrate 20. Become. However, in order to increase the productivity, the phosphor paste is simultaneously filled in a large number of nozzles. Therefore, if a servo mechanism is provided to all the nozzles, the cost of the apparatus increases, which is not very realistic.

According to the phosphor paste layer forming method of the present invention, the diameter of the phosphor paste is sufficiently small at the position where the phosphor paste is separated, and the phosphor paste is separated by the force of the electric field. Hardly affected by the orifice section. Therefore, it is not necessary to control the distance to the substrate so strictly.

The phosphor layer forming apparatus will be described PDP phosphor layer forming apparatus of the present invention. FIG. 5 is a diagram illustrating an overall configuration of the phosphor paste layer forming apparatus, and FIG. 6 is a diagram illustrating an example of a form of a discharge unit.

In FIG. 5, the PDP glass substrate 6 having the ribs 8 formed thereon is set on the XY stage 5, and the center of the orifice of the phosphor paste discharge section 1 is partitioned by the ribs 8 by a positioning mechanism (not shown). The alignment is performed so as to be directly above the center of the recess 9 thus formed.

In FIG. 5, the discharge section 1 is of a type in which a number of orifices are provided on the bottom surface of a container for accommodating the phosphor paste, and the orifices are arranged in a line at the bottom of the container. In this case, by setting the pitch of the orifices to be three times the pitch of the ribs 8, the same color phosphor paste can be filled at a time. Further, a power supply 3 for applying a high voltage pulse and a means 4 for applying pressure are provided, and these operations are controlled by the control device 2. The XY stage 5 is also controlled by the control device 2 in the same manner.

As the discharge section 1 of the phosphor layer forming apparatus of the present invention, one as shown in FIG. 6 is used as an example. FIG. 6A shows an overview of the discharge unit 1, and FIG. 6B shows a cross-sectional view thereof.

In FIG. 6A, the material of the phosphor paste accommodating portion 10 is not particularly limited, and stainless steel or brass having excellent rigidity is preferably used to maintain the shape of the discharge portion 1. The tip portion 11 is made of plastic such as Teflon or polyether ether ketone (PEEK), or ceramic. Particularly, macerite (trade name: manufactured by Mitsui Mining Materials Co., Ltd.) is preferably used in consideration of precision workability such as drilling. When wear resistance is taken into consideration, a ceramic material such as alumina or zirconia is used. Furthermore, in order to efficiently apply an electric field to the phosphor paste, it is desirable to use a material having a high dielectric constant, and it is preferable to use a material having a dielectric constant of 10 or more by adding an additive or the like.

When the tip 11 is made of a metal such as stainless steel, it is necessary to provide an insulating joint of at least about 5 mm between the tip 11 and the phosphor paste accommodating section 10.

As shown in the cross-sectional view of FIG. 6B, the tip 11 preferably has a structure in which the width decreases toward the bottom, and the angle α formed by the two surfaces is 90.゜ or less, and preferably 45 ° or less. With such a configuration, the width w of the bottom surface of the tip portion 11 is reduced, and there is an effect of preventing the phosphor paste from spreading and spreading on the bottom surface when discharging is stopped. It is not preferable that the phosphor paste is applied to the bottom surface and spreads or that a liquid pool is formed, since this will hinder the discharge of the phosphor paste. Therefore, the width w of the bottom surface is preferably set to 2 mm or less, and preferably to 3 times or less the diameter of the orifice 13 if possible.

When the tip 11 is insulative, the electrode 12
Are formed. In FIG. 6, a number of orifices 11a
However, the electrode 12 does not necessarily have to be provided independently for each orifice 11a, and a common electrode 12 may be provided as shown in FIG. The electrode 12 can be used as an electrode by providing a stainless steel plate or the like near the orifice 11a of the distal end portion 11. In FIG. 6B, a stainless steel plate is embedded in the tip to avoid abnormal discharge. However, the shape is not limited to this, and a thin metal piece such as an aluminum foil is attached to the tip 11. It may be attached, or a rod-shaped thin wire may be installed. In this example, the electrode 12 is connected to the tip 11
Although it is installed on the side part, it may be installed on the bottom part by vapor deposition or coating.

The glass substrate 20 on which the ribs 8 are formed has an electrode layer. However, in the phosphor paste layer forming method of the present invention, it is not necessary to provide an electrode on the opposing substrate, and the electrode is formed. Similarly, a phosphor layer can be formed on a glass substrate having no phosphor.

The described method of adjusting the adjustment then the phosphor paste of the phosphor paste. The phosphor used in the phosphor paste is not particularly limited. For example, in the case of a red phosphor,
₂ O ₃ : Eu, as a green phosphor, Zn ₂ SiO ₄ :
Mn, as a blue phosphor, BaMgAl ₁₀ O ₁₇ : Eu
Are used. The average particle diameter of the phosphor is 0.5 to
Although those having a size of about 15 μm are used,
10 μm can be used. If the average particle diameter is small, problems such as a decrease in the luminous efficiency of the phosphor and a shortened life will occur. In the phosphor paste forming method of the present invention, since the orifice diameter is large, there is no particular limitation on the particle diameter of the phosphor that can be ejected. Can be

As the binder, a general-purpose polymer such as a styrene-based polymer or an acrylic polymer can be used. In particular, a cellulose-based polymer such as ethyl cellulose can be preferably used.

The solvent is used in consideration of the solubility of the binder and the like. When polyethyl cellulose is used, polybutyl carbitol acetate (BCA), terpinol, and a mixed solvent thereof are preferably used.

The viscosity of the phosphor paste is 1000 cps
Preferably in the range of ~ 1,000,000 cps,
If it is less than 1000 cps, it cannot be used because it is difficult to maintain the shapes of the meniscus and the elongated portion in the orifice portion. On the other hand, if the pressure is 1,000,000 cps or more, no discharge from the orifice is performed, and the orifice cannot be used. Further, if the thickness is less than 10,000 cps, it is difficult to maintain the shape of the phosphor layer on the side surface when the phosphor paste is filled between the ribs and dried, which is not preferable.
Therefore, it is preferable to be in the range of 10,000 cps to 1,000,000 cps.

Next, a first embodiment of the present invention will be described.

Green phosphor (P manufactured by Kasei Optronics Co., Ltd.)
1-G1S = 65 wt% of acrylic resin (MP-4009 manufactured by Soken Chemical Co., Ltd. = 10 wt%), solvent: butyl carbitol acetate: terpinol =
1:25 wt% kneading, three-roll processing,
A green phosphor paste was used. When the viscosity of this phosphor paste was measured, it was 70000 cps.

Method for Filling Phosphor Paste Next, a method for filling a phosphor paste by the method for forming a phosphor paste layer of the present invention will be described. FIG. 7 illustrates a method of filling the phosphor paste.

FIG. 7A is a sectional view of the phosphor paste immediately after the filling is started, and FIG. FIG. 7 (c)
Is an oblique view of the state during filling. 7A to 7C, 35 indicates a glass substrate, and 36 indicates a rib.

7A to 7C, when the voltage application is started while applying a pressure, the meniscus formed in the orifice 30 is drawn out, and the extension 32 is formed. Since the tip of the extension portion 32 is thinned by the pulse voltage, the phosphor paste can be filled in the cell having the narrow opening. A part of the phosphor paste is separated and cut at the thin portion at the tip of the extension, and adheres to the glass substrate 35 in the cell (recess) 36a. When the electric field is weak, the phosphor paste may adhere to the glass substrate 35 without being separated at the distal end of the elongated portion without dropping. However, even in this case, the diameter of the phosphor paste in contact with the glass substrate 35 is sufficiently small. The distance between the glass substrate 35 and the orifice 30 does not need to be controlled so strictly because the surface tension of the orifice 30 and the orifice 30 are hardly affected. In addition, due to the lines of electric force, they may adhere to the side surface of the rib 36 instead of the glass substrate 35.

During the filling, since the phosphor paste has already been filled in the cell, the filling is continued with the tip of the extending portion 32 being in contact with the already filled phosphor paste (FIG. 9). 7 (b)).

In a state where the tip of the extension portion 32 is not in contact,
A state where the separated droplets fly and adhere is also observed. Usually, the phosphor paste is filled so as to fill the inside of the concave portion 36a divided by the rib 35. When a high-voltage pulse is applied, the tip of the extension portion 32 is drawn to a position closest to the orifice under the influence of the lines of electric force, and therefore, as shown in FIG. A new phosphor paste is supplied in such a manner as to be attracted to the substrate. When the amount of the filled phosphor paste is small, the ribs 3 are larger than the already filled phosphor paste layer.
6 is relatively closer to the top, so that the tip of the extension 32 is more likely to face the top of the rib 36. In addition, it is necessary to fill the phosphor in an appropriate amount because the phosphor does not form near the top of the side surface of the rib after drying and firing. When the filling amount is large and the phosphor paste is piled up to a position higher than the rib, in the next step of filling the adjacent cells with the phosphor paste, the tip of the extending portion 32 faces the raised portion, Problems such as color mixing occur. As described above, it is necessary to control the discharge amount of the phosphor paste and the moving speed of the discharge unit to fill the cell with an appropriate amount of the phosphor paste.

As an appropriate amount, as shown in FIG.
It is preferable that the phosphor paste is exactly filled in the concave portion 36a partitioned by the rib 36, and the shape becomes as shown in FIG. 8B when the solvent is dried.

In the case where the phosphor pastes of a plurality of colors are successively filled, when the phosphor pastes of the second and subsequent colors are filled, the phosphor is already filled in one or both adjacent cells. . If the amount of the phosphor paste filled in the next cell is large and the phosphor paste is piled up at a position higher than the rib height, the phosphor paste in the next cell may be At this point, the tip of the elongated portion of the phosphor paste to be filled is likely to face, causing color mixing. Such color mixing can be avoided by accurately aligning the rib position of the glass substrate on which the ribs are formed with the orifice position of the coating portion of the phosphor paste forming apparatus. Each time it is filled, it is possible to eliminate the need for forming a concave portion in the center of the cell by drying it to remove the solvent.

[0061] adjustment of the discharge amount will, in the PDP phosphor layer forming method of the present invention, will be described a method of adjusting the discharge amount of the phosphor paste.

Here, the case where the ribs 36 are formed at a pitch of 300 μm will be described. Since the cross-sectional area of such a rib is about 6.5 × 10 ^-2 mm ² , the filling speed depends on the moving speed of the glass substrate or the discharge section.
It is necessary to control the discharge amount of the phosphor paste. For example, if the moving speed is 30 mm / sec, about 1.2 μm
It is necessary to fill at a discharge rate of l (liter) / sec.

FIG. 9 shows the result of measuring the relationship between the pressure applied to the container and the discharge amount of the phosphor paste using the nozzle-shaped discharge unit. The measurement conditions are shown below.

Nozzle material: PP (polypropylene) Nozzle length: 20 mm Orifice diameter (nozzle inner diameter): 300 μm Distance between orifice and base material: 500 μm Waveform: rectangular Frequency: 1 kHz Offset voltage: 0 V Amplitude: 5 kV According to pressure The discharge rate is increasing. From this, it is necessary to set the discharge rate to 1.0 μl / sec by about 4.6.
It turns out that it is good if it is atmospheric pressure. Further, when the ejection amount was measured under the same conditions as above while fixing the pressure and changing the voltage application condition, no large change was observed in the ejection amount.

Here, the case where the filling is performed at a constant speed has been described, but the case where the phosphor paste is filled while changing the speed will be described. FIG. 10 shows a case where the filling is performed under the condition that the speed is increased at a constant acceleration from the stop state and the speed becomes constant after 5 seconds.

FIG. 10A shows the moving speed of the glass substrate 35 or the orifice 30, FIG. 10B shows the change in the discharge amount of the phosphor paste, and FIG. 10C shows the case where the discharge amount is controlled by the pressure. , And changes in the pressure to be applied.

As shown in FIGS. 10 (a), 10 (b) and 10 (c), the phosphor paste is uniformly filled over the entire surface by increasing the pressure while controlling the pressure in accordance with the change in the moving speed. can do.

Here, the method of controlling the discharge amount by the pressure has been described. However, in the region where the moving speed is slow and the discharge amount is small, the discharge amount can be adjusted by the voltage application condition. Alternatively, the discharge amount increases as the frequency increases. Also, when the moving speed is slow and the discharge amount is small, if the amplitude of the pulse voltage is too large, the tip of the extended portion of the phosphor paste is separated at a position higher than the top of the rib and scattered, so that the adjacent portion is adjacent to the rib. Since a problem such as mixing in the cell occurs, it is necessary to adjust the voltage application condition to an appropriate value.

When the phosphor paste is filled in the concave portion 36a divided by the rib 36 having a small pitch of about 100 μm, the discharge amount is reduced because the cross-sectional area is reduced, and the applied pressure is reduced. Is also smaller. In such a case, the ejection amount can be similarly adjusted under the voltage application condition.

FIGS. 10 (a), 10 (b) and 10 (c) show an example of the control of the discharge amount. The rheological characteristics of the phosphor paste, the diameter of the orifice 30 of the discharge portion, the nozzle length and the like are shown. Since the discharge amount changes depending on the conditions, the discharge amount can be controlled by appropriately changing the pressure to be applied and the voltage application condition according to each case.

[0071]

According to the present invention as described above, 1000
A high-viscosity phosphor paste of cps to 1,000,000 cps can be stably filled in cells partitioned by partition walls, and the phosphor is not wasted. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a method of controlling the shape of a stretched portion of a phosphor paste by applying a high-voltage pulse.

FIG. 2 is a diagram for explaining an effect of a high voltage pulse.

FIG. 3 is a diagram showing an example of an applied voltage condition.

FIG. 4 is a diagram for explaining the principle of a normal dispenser to which a high-voltage pulse is not applied.

FIG. 5 is a diagram showing an overall configuration of a phosphor paste layer forming apparatus of the present invention.

FIG. 6 is a view showing an example of a discharge section of the phosphor paste layer forming apparatus of the present invention.

FIG. 7 is a view for explaining a state of filling a phosphor paste by the phosphor paste layer forming apparatus of the present invention.

FIG. 8 is a cross-sectional view of a PDP on which a phosphor paste layer is formed.

FIG. 9 is a diagram illustrating an example of a discharge amount of a phosphor paste and pressurizing conditions.

FIG. 10 shows a phosphor paste filling method of the present invention.
The figure for explaining the control method of the discharge amount of phosphor paste.

FIG. 11 is a perspective view illustrating the configuration of a plasma display panel.

FIG. 12 is a sectional view of a plasma display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge part 2 Control device 3 Power supply 6 Glass substrate 7 Phosphor paste 10 Phosphor paste storage part 11 Tip 11a Orifice 12 Electrode 14 Phosphor paste 17 Meniscus 18 Extension part 20 Glass substrate 30 Orifice 31 Phosphor paste 32 Extension part 35 Glass substrate 36 Rib 38 Phosphor layer

Claims (9)

[Claims] 1. A step of forming a concave portion partitioned by a rib on a substrate; Forming a phosphor paste layer by applying a high-voltage pulse to the phosphor layer forming apparatus to extract and extend the meniscus, cutting and separating a part of the meniscus to form a phosphor paste layer in the concave portion, Drying the body paste layer and removing components other than the phosphor in the phosphor paste layer to form a phosphor layer in the concave portion. A method for forming a PDP phosphor screen, comprising: 2. A step of forming a concave portion partitioned by a rib on a substrate, and a step of forming a phosphor layer forming apparatus having an orifice and containing a phosphor paste therein to pressurize the phosphor paste to fluoresce from the orifice. Extruding the body paste, applying a high-voltage pulse to the phosphor layer forming apparatus, controlling the shape of the phosphor paste extruded from the orifice by an electric field, and controlling the shape of the phosphor paste from the orifice diameter to Filling the recesses with the phosphor paste while reducing the diameter, drying the phosphor paste layer and removing the components other than the phosphor in the phosphor paste layer to form a phosphor layer in the recesses A method for forming a PDP phosphor screen, comprising: 3. The phosphor paste has a viscosity of 1000 cps.
The PDP phosphor screen forming method according to any one of claims 1 and 2, wherein the method is carried out at a rate of up to 1,000,000 cps. 4. The phosphor paste according to claim 1, wherein said phosphor paste has a particle size of 1 to 10 μm.
3. The method for forming a PDP phosphor screen according to any one of 2. 5. The method according to claim 1, wherein an inner diameter of the orifice is not less than a rib pitch and not more than three times the rib pitch. 6. The discharge amount of the phosphor paste from the orifice is controlled by the application condition of the pulse voltage, and the relative speed between the orifice and the substrate is controlled in accordance with the discharge amount so that the orifice is moved relative to the rib forming direction. The method for forming a PDP phosphor screen according to any one of claims 1 to 5, wherein the phosphor paste is filled from the orifice while moving the phosphor screen. 7. An orifice is formed by controlling the discharge amount of the phosphor paste from the orifice by changing the pressure applied to the phosphor paste and controlling the relative speed between the orifice and the substrate in accordance with the discharge amount. 6. The PDP according to claim 2, wherein the phosphor paste is filled from the orifice while being relatively moved in the direction.
Phosphor screen formation method. 8. The discharge amount of the phosphor paste from the orifice is controlled by the pressure applied to the phosphor paste and the application condition of the pulse voltage, and the relative speed between the orifice and the substrate is controlled according to the discharge amount. 6. The filling of the phosphor paste from the orifice while relatively moving the orifice in the rib forming direction.
The method for forming a PDP phosphor screen according to any one of the above. 9. A PDP according to any one of claims 1 to 8.
Forming by filling and drying the first color phosphor layer in the concave portion using the phosphor screen forming method, and then filling and drying the second and third color phosphor layers in the concave portion. A method for forming a PDP phosphor screen, comprising the steps of: