JP2008016219A - Method of manufacturing plasma display-panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively achieve a high-definition plasma display panel while eliminating a phosphor paste deposited on the top of each rib. <P>SOLUTION: A plasma display-panel manufacturing method is used for forming each phosphor layer 12 respectively in a plurality of discharge cells 2 formed by each rib 8. After forming a vehicle layer 11 composed of a resin and a solvent in each discharge cell, the phosphor paste 9 is ejected from a nozzle so as to apply it onto the vehicle layer in each discharge cell. Collision energy at the time of landing the phosphor paste 9 ejected from the application nozzle 10 is absorbed by the vehicle layer, so as to prevent the deposition of the phosphor paste on the top of each rib and the occurrence of color mixture due to splashing of the phosphor paste at the time of its landing. Wettability at the bottom of each discharge cell 2 is changed by the vehicle layer 11, so as to prevent the deposition of the phosphor paste on the top of each rib while improving leveling properties. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing an AC type plasma display panel used for a display device or the like, and more particularly to a method of forming a phosphor layer in a discharge cell.

  As a display device that can display high-definition television images on a large screen because it can display at high speed compared to a liquid crystal panel and is easy to increase in size, it emits light by exciting phosphors with ultraviolet light from rare gas discharge. Therefore, there is an increasing expectation for a plasma display device using a plasma display panel (hereinafter referred to as PDP) that displays an image. In addition, PDPs are attracting attention as large-screen display devices for high-definition television. Therefore, development of PDP manufacturing technology aiming at improved display quality and higher reliability such as higher definition and higher brightness has become increasingly important. Yes.

  In general, an AC type PDP adopts a three-electrode structure, and has a structure in which a front plate and a back plate are arranged to face each other at a predetermined interval.

  The front plate is a glass substrate, a display electrode composed of a striped transparent electrode and a bus electrode formed on one main surface of the glass substrate, and a dielectric that acts as a capacitor that covers the display electrode and accumulates charges. The body layer and an MgO protective film formed on the dielectric layer. The dielectric layer usually has a predetermined viscosity obtained by kneading a powder such as Pb-B (lead borosilicate) -based low melting glass as an inorganic component, a resin such as ethyl cellulose as a binder component and a solvent. Formed by applying a dielectric paste having a predetermined film thickness on one main surface of the front plate on which the display electrodes are formed by a printing method, a batch application method or a transfer method, followed by drying and baking. Is done.

  On the other hand, the back plate is formed by a glass substrate, a striped data electrode formed on one main surface of the glass substrate, a dielectric layer covering the data electrode, a partition formed thereon, and each partition. And a phosphor layer that emits red, green, and blue light applied in the display cell.

  The front plate and the back plate are hermetically sealed with their electrode forming surfaces facing each other, and a discharge gas such as Ne-Xe is discharged from 400 Torr (53.2 kPa) to 600 Torr (79) in the discharge space formed by the barrier ribs. .8 kPa).

  By selectively applying a video signal voltage to the display electrodes, the discharge gas is discharged, and the ultraviolet rays generated thereby excite each color phosphor layer to emit red, green, and blue colors, thereby producing a color image. it's shown.

  2. Description of the Related Art In recent years, various rib structures have been devised in place of the conventional striped rib shape with higher definition and higher brightness of PDP. Among them, ribs with a cross-beam structure are attracting attention because of advantages such as solving the crosstalk problem and improving the light emitting area.

As a method of applying the phosphor in the rib shape, a method of applying the material by intermittently ejecting the material from the nozzle by an ink jet method or a dispenser method, or a method of forming a PDP phosphor layer using a dispenser has been proposed. (See Patent Documents 1, 2, and 3).
Japanese Patent No. 2679036 JP 2004-174342 A JP 2004-261803 A

  However, in the conventional method in which the phosphor paste is intermittently ejected from the nozzle by the ink jet method and applied by the dispenser method, the phosphor paste adheres to the top of the rib, or to the adjacent cells of other colors. Sometimes mixed. As a result, when it adheres to the top of the rib, a wiping process is required, and when it is mixed in an adjacent cell, it cannot be used as a panel and the yield does not increase.

  An object of the present invention is to provide a method for producing a high-definition PDP at low cost by eliminating the step of wiping off the phosphor and increasing the yield when forming the phosphor layer on the ribs of the cross-beam structure. To do.

  The method for producing a PDP of the present invention is a method for producing a plasma display panel in which a phosphor layer is formed in each of a plurality of discharge cells, and after a vehicle layer made of a resin and a solvent is formed in the discharge cells, A body paste is ejected from a nozzle and applied onto the vehicle layer in the discharge cell.

  By such a manufacturing method, when the phosphor paste flying from the nozzle adheres to the discharge cell, the kinetic energy is absorbed by the vehicle to weaken the momentum, and the phosphor paste does not scatter and adhere to the top of the rib. Or can be applied without mixing into adjacent cells. Also, due to the difference between the wettability of the phosphor paste to the vehicle and the wettability of the inside of the cell, the applied paste is leveled faster in the longitudinal rib direction, and the paste does not swell in the center of the cell and adheres to the top of the rib. Will not be lost.

  According to the manufacturing method of the present invention, the phosphor paste can be selectively applied only in the discharge cell without attaching the phosphor paste to the top of the rib or mixing into the adjacent cell by a simple method. High-definition PDP panels can be produced.

  In the production method of the present invention, it is preferable that the vehicle is applied to the discharge cell by any one of spraying, die coating, dispenser, and ink jet. Thereby, it can apply | coat in a short time by apply | coating to a large area collectively.

  The vehicle component is preferably the same component as the vehicle contained in the phosphor paste. This facilitates the mixing of the phosphor paste and the previously applied vehicle, and can be eliminated together with the vehicle contained in the phosphor paste during firing.

  Furthermore, it is preferable that a light reflecting material made of a metal oxide is mixed in the vehicle component. Thereby, after baking of the phosphor paste, a reflective layer can be formed on the base of the phosphor layer, and the brightness of the panel can be increased.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

  The present inventors conducted a three-dimensional flow analysis and observation with a high-speed camera to find out the flow mechanism described later by using a dispenser to observe the state in which the phosphor paste is filled into the discharge cells formed by the ribs having the grid structure. It was.

  The mechanism will be described with reference to FIG. FIG. 1 is a diagram schematically showing how the phosphor paste changes with the passage of time when the phosphor paste is adhered in the rib. 1A shows a change from (1) to (9) over time, and FIG. 1B is a plan view of the state of (9) in FIG. Is shown. However, in consideration of the visibility of the figure, the illustration of the rib shape is simplified, and only the inner wall surfaces of the vertical rib 3 and the horizontal rib 4 are shown.

  Depending on the viscosity of the phosphor paste 1 to be used, when it is intermittently ejected by the dispenser, it does not become a perfect ellipsoidal droplet, but as shown in (1) of FIG. The tip of the flying droplet is round and the entire shape is extended. When applied to the discharge cell 2 in this state, the phosphor paste 1 adhered to the center of the discharge cell 2 is divided into the longitudinal rib 3 on the long side of the discharge cell 2 and the lateral rib 4 on the short side with time. Spread to each. However, since the width of the lateral rib 4 is narrow, the time for the phosphor paste 1 to spread in the direction of the longitudinal rib 3 is short and the time in the direction of the lateral rib 4 is long. Therefore, the phosphor paste 1 gradually rises in the center of the discharge cell 2, and the phosphor paste 1 adheres to the top of the vertical rib 3.

  When the viscosity of the phosphor paste 1 is lowered, the phosphor paste 1 spreads faster in the direction of the horizontal rib 4, but not only adheres to the top of the vertical rib 3 in order to spread quickly in the direction of the vertical rib 3. It gets over the vertical rib 3 and enters the adjacent cell.

  When the viscosity of the phosphor paste 1 is increased, the spread in the direction of the longitudinal rib 3 is slow, so that the adhesion to the rib top portion is reduced, but it is not completely eliminated. On the other hand, if the viscosity is high, it does not spread in the direction of the lateral rib 4 and cannot be completely filled in the discharge cell.

  Further, if the amount applied at one time is reduced, adhesion to the top of the rib is reduced, but from the viewpoint of productivity, it is necessary to completely apply the phosphor paste 1 by one application.

  That is, it is very difficult to completely fill and apply the phosphor paste 1 into the discharge cell 2 without adjusting the viscosity of the phosphor paste 1 without adhering to the tops of the ribs or mixing colors with adjacent cells. It can be said.

  As a result of elucidating these detailed mechanisms, we have found that the above problems can be solved by improving the flow characteristics in the ribs.

  Hereinafter, embodiments of the present invention will be specifically described.

(First embodiment)
FIG. 2 shows a rib having a cross beam structure in the present invention. On the back glass substrate 5 of the back plate 100, a plurality of strip-like data electrodes 6 are arranged in parallel to each other in a direction orthogonal to the scan electrodes and sustain electrodes of the front plate, and a dielectric is formed so as to cover them. Layer 7 is formed. Further, in order to partition a plurality of discharge cells 2 formed by the scan electrodes, the sustain electrodes, and the data electrodes 6, ribs 8 are formed in a grid pattern. The long side of the discharge cell 2 is the vertical rib 3, and the short side is the horizontal rib 4.

  FIGS. 3A to 3D are cross-sectional views showing a state in which the phosphor paste 9 is ejected from the application nozzle 10 and applied in the discharge cell. 4A to 4D are plan views when the discharge cells 2 are viewed from the front side of the opposing substrate corresponding to FIGS. 3A to 3D, respectively.

  FIGS. 3A and 4A show a state immediately before the phosphor paste 9 has landed in the discharge cell 2. The inside of the discharge cell 2 is coated with a vehicle made of a resin and a solvent to form a vehicle layer 11.

  FIGS. 3B and 4B show a state immediately after the phosphor paste 9 has landed in the discharge cell 2. The vehicle layer 11 absorbs the kinetic energy of the phosphor paste 9, thereby reducing the impact of landing.

  Thereafter, as shown in FIGS. 3C and 4C, the phosphor paste 9 spreads in the left-right direction of the discharge cell 2 and the vertical direction of the discharge cell 2. Since the discharge cell 2 is filled with the vehicle layer 11, the wettability in the discharge cell 2 is improved, and the phosphor paste 9 that has landed in the center of the cell is compared with the case where the vehicle layer 11 is not applied. Then, it quickly spreads in the vertical direction of the discharge cell 2, that is, toward the lateral rib 4 side. Therefore, as shown in FIG. 1, the phosphor paste 9 rises to the center of the discharge cell and is prevented from adhering to the top of the vertical rib 3. When dried in this state, the phosphor paste 9 and the vehicle layer 11 cross each other, and the phosphor layer 12 is formed as shown in FIGS. 3 (d) and 4 (d).

  As shown in FIG. 3, the method of applying the vehicle layer 11 into the discharge cell 2 is preferably a method of applying a material directly from the discharge port, such as spray, die coat, dispenser, and ink jet. This is because the vehicle layer 11 can be applied by screen printing, but the cost increases due to the cost of the mask and the mask wiping process. Further, since the vehicle adhering to the rib top portion or the like can be lost when the phosphor layer 12 is baked, it may be adhered to the rib top portion when the vehicle layer 11 is formed. Therefore, a method of applying a large area in a lump such as spraying or die coating is more preferable.

  The composition of the phosphor paste 9 is mainly composed of phosphor particles, a resin and a solvent, and it is desirable that the components of the vehicle to be applied first are composed of the same resin and solvent as those contained in the phosphor paste. This is because the vehicle layer 11 that acts as an energy absorbing material when the phosphor paste is adhered and the phosphor paste 9 are easy to cross each other, and can be lost all at once during firing.

  As for the amount of the vehicle layer 11 to be applied in the discharge cell, if the height of the rib 8 is 10% or more, the energy at the time of adhering the phosphor paste is suppressed, and the phosphor paste becomes the plan view of FIG. It was found that the discharge cell 2 spreads in the vertical direction and the effect of suppressing adhesion to the top of the vertical rib 3 is high. Therefore, when the height of the rib 8 is 120 μm, the vehicle layer 11 having a thickness of 12 μm or more may be formed. In addition, the height of the rib 8 in this Embodiment was 0.5 mm-1.5 mm.

  The viscosity of the vehicle should be higher than the viscosity of the phosphor paste. The viscosity of the preferred phosphor in the present embodiment is on the order of 1 Pa · s to several tens of Pa · s. When the viscosity is less than this, the material is scattered from the nozzles at the time of discharge and mixed into adjacent cells. When the viscosity is high, the material is difficult to cut from the nozzle, and application by flying becomes difficult. Depending on the method of forming the vehicle layer 11, the range of the viscosity of the vehicle that can be used differs, and the viscosity of the vehicle layer 11 can be increased by heating or cooling the entire back substrate 100 in order to make it higher than the viscosity of the phosphor paste. May be adjusted. For example, when the vehicle layer 11 is formed by spraying, the viscosity of the vehicle applied by spraying is at most about several thousand Pa · s, which is lower than the phosphor concentration.

(Second Embodiment)
A method for manufacturing a PDP in the second embodiment of the present invention will be described with reference to FIG. The basic configuration of the second embodiment is the same as that of the first embodiment, and an application example of the material of the vehicle layer is shown.

  In this embodiment, a light reflecting material made of a metal oxide is mixed in the vehicle layer. FIG. 5A shows a state in which the phosphor paste 9 is applied on the vehicle layer 13 mixed with the light reflecting material.

  Thereafter, the vehicle layer 13 and a part of the phosphor paste 9 are mixed, but since the metal oxide is mixed, it becomes a two-layer state. Thereafter, when the back plate is dried, as shown in FIG. 5B, the phosphor layer becomes a two-layer state of the phosphor layer 12 and the vehicle layer 13 containing the metal oxide thereunder. When the back plate is further baked, as shown in FIG. 5C, the vehicle layer 13 containing the metal oxide becomes a light reflecting layer 14 made of only the metal oxide by decalcification. The phosphor layer 12 is also baked to form a phosphor layer 15 made of only phosphor particles. Thereby, the light emission of the phosphor layer 15 can be reflected by the light reflection layer 14 without escaping to the back surface of the back plate, thereby improving the light emission efficiency.

  As for the coating method of the vehicle layer 13, if it is applied to the entire back plate as in the first embodiment, the contrast slightly decreases due to the light reflecting material remaining on the tops of the ribs 8 after firing. Therefore, it is preferable to apply into each discharge cell 2 by a dispenser or an inkjet.

  In addition, as a material of the light reflecting material, titanium dioxide is preferable.

  According to the method for producing a PDP of the present invention, the step of wiping off the phosphor paste attached to the top of the rib can be eliminated, and a phosphor layer with higher luminance can be formed. This is useful as a method for manufacturing a display device such as a large monitor.

Explanatory drawing which shows the adhesion mechanism of the phosphor paste to the rib top part at the time of phosphor layer formation The perspective view which shows the structure of the backplate of the plasma display panel in the 1st Embodiment of this invention Sectional drawing which shows typically a mode that the shape of a fluorescent substance layer changes in the process of the manufacturing method of the plasma display panel in the 1st Embodiment of this invention. Plan views respectively corresponding to the diagram of FIG. Sectional drawing which shows typically the shape change of the vehicle layer containing a metal oxide, and a fluorescent substance layer in the process of the manufacturing method of the plasma display panel in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Phosphor paste 2 Discharge cell 3 Vertical rib 4 Horizontal rib 5 Back glass substrate 6 Data electrode 7 Dielectric layer 8 Rib 9 Phosphor paste 10 Application nozzle 11 Vehicle layer 12 Phosphor layer 13 Vehicle layer containing metal oxide 14 Light reflection Layer 15 Phosphor layer after firing

Claims (4)

  A method of manufacturing a plasma display panel in which a phosphor layer is formed in each of a plurality of discharge cells, and after forming a vehicle layer made of a resin and a solvent in the discharge cell, the phosphor paste is allowed to fly from a nozzle to A method of manufacturing a plasma display panel, wherein the plasma display panel is coated on the vehicle layer in a discharge cell.   2. The method of manufacturing a plasma display panel according to claim 1, wherein the vehicle is applied to the discharge cell by any one of spraying, die coating, dispenser, and inkjet.   The method of manufacturing a plasma display panel according to claim 1, wherein the component of the vehicle is the same component as the vehicle contained in the phosphor paste. 2. The method of manufacturing a plasma display panel according to claim 1, wherein a light reflecting material made of a metal oxide is mixed in the vehicle component.

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