JP3219059B2 - Display panel manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a display panel used for a display device or the like.

[0002]

2. Description of the Related Art A conventional alternating current (AC) type plasma display panel has a display electrode on a front cover plate (front glass substrate), on which a dielectric glass layer and MgO have a crystal orientation of (111). ) The surface is covered with an oriented magnesium oxide (MgO) dielectric protective layer. Conventionally, for this MgO dielectric protective layer, a vacuum deposition method using electron beam heating and mainly using MgO as a raw material has been used.

Also, a back glass substrate (back plate)
An address electrode, a partition, and a phosphor layer are provided on the substrate. A screen printing method is mainly used to form the electrode layers (display electrode and address electrode), and a screen printing method is used to form the phosphor layer. Method (see, for example,
2019, an ink-jet method (for example, JP-A-53-79371), and a photoresist film method (for example, JP-A-6-273925).

[0004] The luminance of a panel conventionally developed as a plasma display panel is 40 inches NTS.
C panel (640 x 480 cells, cell pitch 0.43 mm x 1.29 mm, cell area about 0.55 m
m ² ) was about 250 cd / m ² .

[0005]

In recent years, expectations for high-definition, large-screen televisions including high-definition televisions have been increasing. CRTs are superior to plasma displays and liquid crystals in terms of resolution and image quality, but they are 40 and 40 in depth and weight.
Not suitable for large screens larger than inches. Liquid crystals have excellent features such as low power consumption and low driving voltage, but have limitations in screen size and viewing angle. On the other hand, a plasma display is capable of realizing a large screen, and products of a 40-inch class have already been developed.

[0006] The brightness of the plasma display currently commercialized depends on the intensity of the ultraviolet rays generated by the discharge of the gas (He-Xe-based gas or neon-Xe-based gas) sealed in the discharge space. I have. Especially H
In the discharge by the e-Xe-based gas, vacuum ultraviolet rays having a wavelength of 147 nm (nanometers) due to the resonance line of Xe are emitted, and the ultraviolet rays of this wavelength mainly excite the red, green, and blue ultraviolet rays applied in the discharge cells. The phosphor is excited to emit light.

The pixel level of the current 40 to 42 inch class plasma display is 640 × 48 pixels.
There are no cells, a cell pitch of 0.43 mm × 1.29 mm, and an area of one cell of 0.55 mm ² .

Further, the pixel level of a full-spec high-vision television which is expected in recent years is 192 pixels.
0 × 1125, the cell pitch is also 0.15 mm × 0.48 mm in the 42 inch class, and the area of one cell is 0.07.
Fineness of ² mm ² .

[0009] Therefore, as the definition of the plasma display advances, the cell pitch and the area per cell become smaller than those of the conventional NTSC. Therefore, a high-precision phosphor film forming technique for improving the luminance is desired. It is rare.

However, the phosphor coating by the screen printing method has a problem that when the partition walls are filled with the phosphor ink, the screen plate is deformed and the adjacent partition walls are filled with the phosphor ink to cause color mixing.

Considering the fine cells, the phosphor coating by the screen printing method has a partition wall pitch of 0.1 mm.
From 0.15 mm to 0.15 mm, since the partition wall has a width, the space filled with the phosphor has a very narrow width of about 0.1 mm to 0.08 mm, and the viscosity is high accurately and quickly by the printing method ( (Tens of thousands of centipoise) It becomes difficult to pour the phosphor ink.

In a phosphor photo film method or a phosphor photo paste method using a phosphor and an ultraviolet photosensitive resin, the phosphor can be embedded in the partition wall with a certain degree of accuracy. There are problems such as the necessity of performing color repetition, color mixing due to undeveloped portions, and difficulty in recovering expensive phosphor materials.

As a phosphor coating method which can solve such problems, Japanese Patent Application Laid-Open No. 53-79371 and Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open No. -162019 discloses an ink jet method in which a desired pattern is drawn on a substrate by ejecting a phosphor ink from a pressurized nozzle. We have also proposed a method of continuously filling and drawing a phosphor between partition walls while continuously jetting a phosphor ink having good fluidity from fine nozzles, as shown in Japanese Patent Application No. 8-245585. I have.

However, such a method of filling the gap between the partition walls while ejecting the phosphor ink having good fluidity from the fine nozzle has the following problems.

In other words, there is a method in which the discharge of the phosphor is not stopped within the time of application to the substrate. However, there is a problem that the ink flows into the adjacent partition at the end of the partition and color mixing occurs.

In view of the foregoing, it is an object of the present invention to provide a method of manufacturing a display panel in which a phosphor layer can be formed accurately and inexpensively on the display panel.

[0017]

According to the present invention, in order to achieve the above object, an ejection nozzle for ejecting phosphor ink and a substrate on which a partition is formed are relatively moved to a predetermined region at an end of the partition. In this case, the method further comprises at least a step of charging the phosphor ink and applying an electric field to forcibly bend the ink discharge flow of the discharge nozzle.

[0018]

Embodiments of the present invention will be described below.

(Overall Configuration and Manufacturing Method of PDP) FIG. 7
1 is a schematic sectional view of an AC discharge type PDP according to an embodiment of the present invention. Although only one cell is shown in FIG.
A PDP is configured by arranging a large number of cells that emit green and blue light.

This PDP has a discharge electrode (display electrode) 12, a dielectric glass layer 13,
address electrodes 16, partition walls 17, phosphor layers 18 on a front panel on which a gO protective layer 14 is disposed, and on a rear glass substrate 15.
The discharge gas is sealed in the discharge space 19 formed between the rear panels provided with the, and is manufactured as described below.

Preparation of Front Panel: The front panel is formed by forming discharge electrodes (display electrodes) 12 on a front glass substrate 11,
It is fabricated by covering the surface with a lead-based dielectric glass layer 13 and further forming an MgO protective layer 14 on the surface of the dielectric glass layer 13.

In this embodiment, a discharge electrode (display electrode)
Reference numeral 12 denotes a silver electrode. The front glass substrate 1 is formed by screen printing a silver electrode ink containing an ultraviolet-sensitive resin.
After being uniformly coated on the substrate 1 and dried, it is formed by patterning by exposure and development and baking.

The dielectric glass layer 13 is formed by screen printing and firing. Also, the MgO protective layer 14
Is made of magnesium oxide [MgO] and is formed by a sputtering method, a vacuum evaporation method, or the like.

Fabrication of the back panel: The back panel has address electrodes 16 formed on a back glass substrate 15, and stripe-shaped barrier ribs 17 made of glass are formed thereon at a predetermined pitch. It is manufactured by forming a phosphor layer 18 of a red phosphor, a green phosphor, and a blue phosphor in each space.

In the present embodiment, the address electrodes 16 are silver electrodes, and a silver electrode ink containing an ultraviolet-sensitive resin is uniformly applied on the rear glass substrate 15 by a screen printing method. After drying, patterning by exposure and development and baking are performed.

Further, the partition wall 17 may be formed by repeatedly printing several times by a screen printing method, or a so-called sand blast method or a lift-off method may be used.

The phosphor layer 18 is formed by applying a red phosphor, a green phosphor, and a blue phosphor to each space sandwiched by the partition walls 17 by an ink discharge method. As the phosphor of each color, a phosphor generally used for a plasma display panel can be used. Here, the following phosphor is used.

"Red phosphor": (Y _X Gd _{1 -X} ) BO ₃ :
Eu ³⁺ or YBO ₃ : Eu ³⁺ “green phosphor”: BaAl ₁₂ O ₁₉ : Mn or Zn
₂ SiO _4: Mn "blue phosphor": BaMgAl ₁₀ O _17: Eu ²⁺ panel bonded in accordance PDP manufacturing of: Next, bonded together with a sealing glass of the front panel and the rear panel produced in this way At the same time, the inside of the discharge space 19 partitioned by the partition wall 17 is evacuated to a high vacuum (8 × 10 ⁻⁷ Torr), and then a discharge gas of a predetermined composition is sealed at a predetermined pressure to produce a plasma display panel. .

The composition of the discharge gas to be filled is a conventional Ne--Xe system, but the content of Xe is set to 5% by volume or more, and the filling pressure is 500 to 800 Torr.
Set to the range of r. In FIG. 7, the front panel is rotated 90 degrees unlike the actual case.

Next, a method for forming a phosphor layer using the present invention will be described below. A method for forming a phosphor layer in each space partitioned by a partition will be described with reference to FIG. FIG.
FIG. 2 is a schematic view of an ink ejection device used when forming a phosphor layer of a plasma display panel.

In FIG. 2, reference numeral 20 denotes a phosphor ink;
Is a nozzle for discharging the phosphor ink 20, 22 is a server for supplying the phosphor ink 20 to the nozzle 21, 23 is
Is a pressurizer for applying pressure to the nozzle 21.

First, when the phosphor ink 20 of a specific color is put into the server 22 and pressure is further applied by the pressurizer 23, the phosphor ink 20 is discharged from the nozzle 21 as a continuous stream 24. At this time, the center of the nozzle 21 is positioned at the center between the stripe-shaped partitions 26 provided on the back glass substrate 25, and the phosphor ink 20 is filled between the partitions 26.

FIG. 3 shows an outline of an actual coating apparatus main body.
In FIG. 3, reference numeral 27 denotes an apparatus main body, and a main body base 28
A rear substrate 29 is placed on the top, and a driving device (not shown)
As a result, it reciprocates linearly on the rail 30 on the base 28 in the direction of arrow 31 (longitudinal direction of the partition) (this is referred to as X-axis movement). At this time, the rear substrate 29 is placed on the base such that the stripe-shaped partition walls 32 provided on the rear substrate 29 are parallel to the linear reciprocating motion.

On the other hand, an arm 33 is provided on the main body 27 so as to be orthogonal to the partition wall 32. The arm 33 is provided with the nozzle or the ink discharge device main body 34 shown in FIG. (Along a direction substantially perpendicular to the longitudinal direction of the partition wall) and linearly reciprocate (this is referred to as Y-axis movement). These movement operations are performed by commands from the control device 36 through a cable 37 for X-axis movement and a cable 38 for Y-axis movement.

In such an apparatus, when the rear substrate 29 moves at a high speed in one direction of the arrow 31, ink is filled between predetermined partitions from nozzles arranged as shown in FIG. During the return operation, the ejection device is sent in one direction of the arrow 35, and the space between the next partition walls is filled with ink. By this repetitive operation, the phosphor ink is filled between the partition walls 32 on the entire rear substrate 29.

At this time, for each color of the phosphor ink, one color may be applied over the entire surface and then the next color may be applied.
A discharge device for the color may be provided on the arm and applied simultaneously.

The number of partitions depends on the definition of the screen, but is several hundred to several thousand. Therefore, it is important to shorten the tact by using a plurality of application nozzles. For example, the number of nozzles is set to three.

The nozzle head body has a header for the purpose of ink distribution and pressure equalization, and a nozzle having a fine hole diameter is provided at the lower portion thereof. Is connected. The distance L between the rear substrate located below the nozzle head and the upper end of the partition wall depends on conditions, but is 2 to 3 mm. The nozzle diameter is determined by the partition pitch and the partition width, or the amount of ejected ink, and is about several tens to 100 μm.

At this time, when the pitch of the partition walls is P1, the phosphors of R, G, and B are alternately applied to the respective partition spaces, so that the nozzle pitch is 3 × P1, and each nozzle is divided into partition walls. Initially, the substrate is set so as to be located at the center between them, and the phosphor ink is filled between the partition walls by the operation described with reference to FIG. The nozzle head body is fed by a distance of 3 × 3 × P1 by the reciprocation of the substrate, each nozzle is positioned at the center between the partition walls, and the phosphor ink is filled between the partition walls by the continuous flow of the phosphor ink. is there.

In such a method, since it is necessary to continuously discharge the phosphor ink from a nozzle having a diameter of 100 μm, the ink viscosity is set to be about two orders of magnitude lower than that of the ink used for conventional screen printing and the like. , It is necessary to increase liquidity.

FIG. 4 shows the situation when the phosphor ink is filled in the partition walls of the rear substrate in this way. This case shows, for example, a case where R color is filled.
As shown in FIG. 4, the end of the partition is normally open.
Therefore, when the phosphor ink has a low viscosity, a phenomenon occurs in which the phosphor ink flows into an open end and wraps around an adjacent partition.

To solve this problem, there are various methods, for example, a structure in which a partition is closed, a method of covering at an end,
For example, there is a method of stopping the discharge from the nozzle in the end region.

However, these methods are not preferable from the viewpoints of influence on other processes, mass productivity, and nozzle ejection stability.

According to the present invention, the phosphor ink is charged while the discharge nozzle relatively moves in a certain area at the end of the partition wall, and an electric field is applied by the charge to forcibly discharge the ink. The fluorescent material is bent and sucked by a suction port provided in the vicinity, thereby stopping the application of the phosphor to the area at the end.

(Embodiment) FIG. 5 shows an outline of an embodiment of the present invention.

A partition 51 is provided on the substrate 51.
The substrate 51 reciprocates as indicated by a dashed line arrow as shown in the figure. At this time, a nozzle head unit 53 having the above-described nozzle is positioned above the substrate at a predetermined distance from the partition wall 52, and the ink discharge flow 54 is discharged downward from the nozzle.

At this time, a suction port 55 for sucking ink is provided between the partition and the nozzle head unit, and a suction force is applied to this port by a suction pump or the like.

FIG. 5A shows a case in which the substrate moves in the direction of the solid arrow c, and it is desired to stop the ink discharge flow to the partition in the end region A of the partition.

When the ink discharge flow 54 relatively enters the end of the substrate 51, the suction port 55 provided on the upper part is made to protrude in the direction of arrow d to suck the ink, and as shown in FIG. On the other hand, when it deviates from the area, the suction port 55 is retracted in the direction of arrow e to supply ink into the partition.

This operation is similarly performed in the end region B on the opposite side of the substrate, and basically, it is possible to prevent the ink from flowing around in the end region.

The length of the end regions A and B is determined by the flowability in the partition wall due to the viscosity of the ink used, the region of the partition wall, etc., but is approximately several millimeters.

In the above-described method, basically, the insertion of the ink into the partition in the predetermined area is stopped, and the occurrence of color mixing or the like due to the wraparound at the end can be stopped.
As shown in (1), when ink is received at the suction port, some unstable factors such as the generation of ink droplets 61 occur.

Therefore, in the present embodiment, a configuration of a coating apparatus for surely preventing them will be described with reference to FIG. The substrate 51, the partition 52, the nozzle head unit 53 and the like are the same as those in FIG.

In this embodiment, the suction ports 55 and 56 are provided on the left and right or near the periphery of the ink discharge flow, and the space f between them is a gap through which the ink discharge flow 54 can freely pass. At this time, the nozzle is provided with a charging means 57 for charging the ink, and the suction port is further provided with electric field applying means 58a, 58 for deflecting the flow of the charged ink.
b is provided.

First, as shown in the figure, in a region where the substrate 51 moves in the direction of the arrow and the ink discharge flow 54 enters the end portion,
First, the ink is charged by charging means 57 provided in the nozzle head unit 53, a suction electric field is applied at the suction port A55, and a repulsive electric field is applied at the suction port B56, so that the ink discharge flow 54 is directed toward the suction port A55. Then, the ink is bent and sucked, and the application to the partition walls 52 is stopped.

Next, when the vehicle passes the stop region and enters the application region, the application of the electric field is released as shown in FIG.
The coating on the partition walls is performed regularly.

Further, when the substrate advances and enters the coating stop area on the opposite side, as shown in FIG. 1C, it is charged by the charging means 57 in the same manner as before, and the suction on the opposite side is used. The electric field application is switched so as to suck in the port B56.

By doing so, the ink is reliably sucked into the suction port, the coating can be stably and reliably stopped in the end area, and the occurrence of color mixing can be suppressed. Further, in this case, there is no need to mechanically move the suction port, and a very stable operation can be performed. For example, the suction ports 55 and 56 and the nozzle head unit 53 may be arranged integrally. in this case,
The positional relationship between the nozzle head unit 53 and the suction ports 55 and 56 is relatively fixed and moves integrally.

At this time, it goes without saying that the voltage to be applied may be changed depending on the type of ink.

In addition, it is preferable that the ink discharge flow is continuously discharged for a predetermined time without stopping. It is preferable to keep the discharge state continuously for a plurality of days or a week.

As described above, according to this embodiment, when the discharge nozzle for discharging the phosphor ink and the substrate on which the partition is formed relatively move to a predetermined region at the end of the partition, the phosphor ink is discharged. In addition to the step of charging and forcibly bending the ink discharge flow of the discharge nozzle so that the phosphor is not applied between the partition walls in a predetermined region at the end of the partition wall, the ink discharge flow is continuously performed without stopping the ink discharge flow. In addition, the coating can be applied uniformly and continuously to the inside of the partition walls, and the mass productivity can be particularly improved.

Further, the phosphor sucked in through the suction port can be reused, and is excellent in terms of resource saving without waste.

[0063]

As described above, according to the present invention, it is an unprecedented and excellent method by which a phosphor layer can be formed with high accuracy and stability at a low cost. It is an excellent method that can be applied and is particularly applicable to mass production.

[Brief description of the drawings]

FIG. 1A to FIG. 1C are manufacturing process diagrams using a coating apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of the ink ejection device of the present invention.

FIG. 3 is a perspective view schematically showing a coating apparatus main body of the present invention.

FIG. 4 is a diagram showing a state of a partition and phosphor ink in the present embodiment.

5 (a) and 5 (b) are process diagrams schematically showing edge coating.

FIG. 6 is a schematic diagram showing a situation of edge coating.

FIG. 7 is a cross-sectional view of the plasma display panel according to the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Front glass substrate 12 Discharge electrode (display electrode) 13 Dielectric glass layer 14 MgO protective layer 15 Back glass substrate 16 Address electrode 17 Partition wall 18 Phosphor layer 19 Discharge space 51 Substrate 52 Partition wall 53 Nozzle head unit 54 Ink discharge flow 55 Suction Port 56 Suction port 57 Charging means 58 Electric field applying means

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kanako Miyashita 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-53-79371 (JP, A) JP-A-10- 228863 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 9/227 H01J 11/00-11/04 H01J 17/00-17/06 H01J 17/49

Claims (8)

(57) [Claims] 1. A substrate on which a partition is formed and a phosphor ink are discharged.
Relative to the discharge nozzles
A method for manufacturing a display panel, wherein
The phosphor ink charged in an end region of the partition wall
From the discharge nozzle and applying an electric field
The discharged phosphor ink is bent, and the end of the partition wall is bent.
Manufacturing method of a display panel that is not applied to a part area. 2. The method according to claim 2, wherein said phosphor ink is provided by said discharge nozzle.
2. The charging device according to claim 1, wherein the charging is performed when the charging device is located at an end region of the partition.
Display panel manufacturing method. 3. A suction port for drawing the bent phosphor ink.
3. The data according to claim 1 or 2, wherein
A method for manufacturing a display panel. 4. An ink discharge flow is continuously discharged for a predetermined time.
A display panel according to any one of claims 1 to 3.
Manufacturing method of flannel. 5. An ejection nozzle for ejecting phosphor ink, and
The relative movement between the discharge nozzle and the substrate on which the partition wall is formed
Means for charging, and charging means for charging the phosphor ink
And the phosphor ink discharged from the discharge nozzle
To bend and not be formed in the end region of the partition wall
Phosphor coating device provided with means. 6. The charging means discharges the phosphor ink.
Charges when the exit nozzle is located in the end region of the partition
The phosphor coating device according to claim 5. 7. A suction device for sucking the bent phosphor ink.
7. The phosphor coating according to claim 5, which has a pull port.
Cloth equipment. 8. An ink discharge flow is continuously discharged for a predetermined time.
A phosphor coating device according to any one of claims 5 to 7.
Place.