JP2011009028A - Manufacturing method of plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a plasma display panel in which coating condition of a phosphor is excellent by using a phosphor ink containing an optimal amount of dispersant.SOLUTION: The manufacturing method of a plasma display panel comprises a process in which barrier ribs (for example, barrier ribs 9) are formed and a plurality of recessed parts (for example, discharge cells 11) partitioned by the barrier ribs are formed and a process in which a phosphor ink is coated on the recessed parts using an ink jet device. The phosphor ink contains a red phosphor (12a) and a dispersant (12b). The addition amount of the dispersant is 0.0001 g or more and 0.02 g or less per surface area 1 mof the red phosphor.

Description

  The present invention relates to a manufacturing method of a plasma display panel used for image display, and more particularly to a manufacturing method using an inkjet device.

  In recent years, a plasma display panel (hereinafter abbreviated as “PDP”) has been attracting attention as a color display device capable of realizing a thin and lightweight on a large screen.

  In such a PDP, an ink jet method capable of applying a phosphor has been proposed (see Patent Document 1). Patent Document 1 shows a method in which an ink in which a phosphor having an average particle size of 0.001 μm or more and less than 1.0 μm is dispersed in an organic solvent is produced and ejected from the tip of an inkjet head. Patent Document 2 discloses that an ink having a viscosity of 1.5 to 200 mP · s and a surface tension of 15 to 50 mN / m is used as the phosphor-containing ink ejected by inkjet.

Japanese Patent Laid-Open No. 2004-63246 JP 2000-11875 A

  The present inventors have found that the application state of the phosphor varies depending on the amount of the dispersant in the phosphor ink. No proposal has been made so far for the optimum amount of dispersant in the phosphor ink.

  An object of the present invention is to provide a method of manufacturing a plasma display panel in which a phosphor is applied in a good state using a phosphor ink containing an optimal amount of a dispersant.

The above object can be realized by the following manufacturing method. The manufacturing method is a manufacturing method of a plasma display panel,
Forming a partition and forming a plurality of recesses separated by the partition;
Applying a phosphor ink to the recess using an inkjet device;
Have
The phosphor ink includes a red phosphor and a dispersant,
The amount of the dispersant added is 0.0001 g or more and 0.02 g or less per 1 m ² of the surface area of the red phosphor.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a plasma display panel with the favorable application | coating state of fluorescent substance can be provided.

The disassembled perspective view which shows the structure of PDP in 1st Embodiment of this invention. Sectional drawing which shows the discharge cell part of PDP in 1st Embodiment of this invention. The figure which shows the electrode arrangement | sequence of PDP in 1st Embodiment of this invention. Sectional drawing which shows the principal part which showed an example of the droplet discharge in 1st Embodiment of this invention Cross-sectional shape view when the phosphor ink is applied in the first embodiment of the present invention Sectional drawing which shows the mode of the process of the principal part in 1st Embodiment of this invention. The schematic diagram which shows the relationship between the fluorescent substance particle in 1st Embodiment of this invention, and a dispersing agent. Sectional drawing for demonstrating the mode after fluorescent substance layer formation in 1st Embodiment of this invention Schematic which shows the structure of the PDP apparatus in 2nd Embodiment of this invention.

[First Embodiment]
(Configuration of PDP)
FIG. 1 is an exploded perspective view showing the structure of the PDP 100 in the first embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the main part of the discharge cell portion.

  As shown in FIG. 1, the PDP 100 includes a front plate and a back plate arranged to face each other. A large number of discharge cells 11 are formed between the front plate and the back plate.

The front plate has a front substrate 1, a scan electrode 2, a sustain electrode 3, a dielectric layer 4, and a protective layer 5. The front substrate 1 is made of glass. On the front substrate 1, a plurality of pairs of display electrodes composed of a pair of scanning electrodes 2 and sustaining electrodes 3 are formed in parallel to each other. Scan electrode 2 and sustain electrode 3 are formed in a pattern that repeats in the arrangement of scan electrode 2 -sustain electrode 3 -sustain electrode 3 -scan electrode 2. A dielectric layer 4 is formed so as to cover these display electrodes. A protective layer 5 made of MgO is formed so as to cover the dielectric layer 4. Scan electrode 2 and sustain electrode 3 are made of conductive electrodes such as ITO, SnO ₂ , ZnO and the like, and transparent electrodes 2a and 3a made of light such as light, and bus electrodes 2b and 3b made of metal such as Ag. Is formed.

  The back plate has a back substrate 6, a data electrode 7, a dielectric layer 8, and a partition wall 9. The back substrate 6 is made of glass. On the back substrate 6, a plurality of data electrodes 7 made of a conductive material mainly composed of mutually parallel Ag are formed. A dielectric layer 8 is formed so as to cover the data electrode 7. Further, a grid-like partition wall 9 is formed on the dielectric layer 8. The barrier ribs 9 divide adjacent discharge spaces. Then, phosphor layers 10 of red, green, and blue colors are formed on the surface of the dielectric layer 8 and the side surfaces of the partition walls 9.

  The front plate and the back plate are arranged to face each other so that the scan electrode 2 and the sustain electrode 3 and the data electrode 7 are three-dimensionally crossed. The periphery of the joint surface between the front plate and the back plate is sealed. A discharge space is formed between the front plate and the back plate. A discharge gas is sealed in the discharge space.

Here, as shown in FIG. 2, in the discharge space sandwiched between the front plate and the back plate, discharge cells 11 are formed in a portion surrounded by the barrier ribs 9. Discharge cell 11 is sandwiched between scan electrode 2, sustain electrode 3, and data electrode 7. The volume of the discharge cell 11 is, for example, 1.75 × 10 ⁻¹² m ³ (longitudinal 250 μm, lateral 70 μm, depth 100 μm).

  FIG. 3 is an electrode array diagram of the PDP in the embodiment. N scanning electrodes Y1, Y2, Y3... Yn (2 in FIG. 1) and n sustaining electrodes X1, X2, X3... Xn (3 in FIG. 1) are arranged in a row. M data electrodes A1... Am (7 in FIG. 1) which are long in the direction are arranged. A discharge cell is formed at a portion where a pair of scan electrode Y1 and sustain electrode X1 intersects with one data electrode A1. M × n discharge cells are formed in the discharge space. Each of these electrodes is connected to a connection terminal provided at a peripheral end portion outside the image display area of the front plate and the back plate.

(Production method)
Below, the manufacturing method of PDP100 by this Embodiment is demonstrated.

  The method for manufacturing PDP 100 includes a step of forming a front plate, a step of forming a back plate, a sealing step between the front plate and the back plate, and a sealing step. The step of forming the back plate includes a step of applying a phosphor. Except for the step of applying the phosphor, since the conventional manufacturing method can be applied, the description thereof is omitted.

  The step of applying the phosphor will be described in detail. An ink jet device is used for applying the phosphor. Specifically, for example, a phosphor ink containing a phosphor is created. The inkjet head is moved on the back plate and scanned. The ink jet head discharges phosphor ink containing a phosphor of a predetermined color in a predetermined amount to the discharge cell 11 surrounded by each partition wall in one scan. At this time, the amount of ink to be dropped is adjusted in consideration of the wettability of the phosphor ink with respect to the material such as the back substrate 6. FIG. 4 is a cross-sectional view of the main part showing an example of droplet discharge in the present embodiment. FIG. 5 is a cross-sectional shape view when the phosphor ink 12 is applied to the barrier rib 9.

As the material of the blue phosphor, BaMgAl ₁₂ O ₁₇ : Eu ³⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , BaMgAl ₁₄ O ₂₃ : Eu ²⁺ , Y ₂ SiO ₅ : Ce, (Ca, Sr, Ba) ₁₉ (PO ₄ ) ₆ C ₁₂ : Eu ²⁺ , (Zn, Cd) S: Ag, or the like can be used.

As a material of the green phosphor, BaAl ₁₂ O ₁₉ : Mn, Zn ₂ SiO ₄ : Mn, YBO ₃ : Tb, or the like can be used.

Examples of the red phosphor material include YBO ₃ : Eu ³⁺ , (Y _x Gd _1−x ) BO ₃ : Eu ³⁺ (0 ≦ X ≦ 1), Y (P, V) O ₄ : Eu ^{3+, and the} like. Can be used. Of course, the blue phosphor, the green phosphor, and the red phosphor are not limited to the above materials. The average particle size of each phosphor is 1 μm or more. Each phosphor having an average particle diameter of 1 μm or more has high luminance. Each phosphor may have an average particle size of less than 1 μm.

  The blue phosphor ink contains a blue phosphor. The green phosphor ink contains a green phosphor. The red phosphor ink contains a red phosphor. In each phosphor ink, each phosphor particle is dispersed in a solvent in which butyl carbitol acetate, terpineol, and ethyl cellulose are dissolved. A dispersant is added to each phosphor ink. The amount of the dispersing agent at this time was added in an amount of 0.5 to 2 wt% with respect to the weight of the phosphor ink, for example. As the dispersant, materials such as acrylic copolymers, alkylammonium salts, and siloxanes can be used.

  The viscosity of each phosphor ink at 25 ° C. is preferably from 10 mPa · s to 40 mPa · s. In this embodiment mode, the molecular weight and content of ethyl cellulose are adjusted so that the viscosity is 10 mPa · s or more and 40 mPa · s or less. When the viscosity of each phosphor ink is lower than 10 mPa · s, the sedimentation of each phosphor particle is accelerated, and each phosphor particle is precipitated and aggregated in the ink jet apparatus. And the density | concentration (content rate) of each fluorescent substance particle in the droplet discharged from the nozzle hole of an inkjet head will not be kept constant, but will vary. As a result, the phosphor layer 10 cannot be formed with a uniform film thickness on the sidewalls of the barrier ribs. Conversely, when the viscosity is higher than 40 mPa · s, it becomes difficult to eject ink from the nozzle holes of the inkjet head.

  Further, since the amount of phosphor ink that can be applied in one partition is determined, the maximum thickness of the phosphor layer formed in one cycle consisting of application, drying, and firing of the phosphor ink is The amount of the phosphor ink and the content of the phosphor contained in the phosphor ink are determined. In order to form a phosphor layer having a predetermined thickness after drying and baking, it may be necessary to perform a cycle of applying and drying the phosphor ink a plurality of times. However, if many cycles are performed, productivity deteriorates. For this reason, the content of the phosphor in each phosphor ink is preferably 40 wt% or more and 70 wt% or less. By doing so, it is possible to reduce the cycle of applying and drying the phosphor ink for forming the phosphor layer having a predetermined thickness as much as possible. For example, a phosphor layer having a predetermined thickness can be formed in one cycle. When the weight ratio of the phosphor in the phosphor ink is less than 40 wt%, the phosphor contained in the ink applied at one time is small, so that a sufficient amount of phosphor ink is added to the inner volume of the partition wall. In order to inject, it is necessary to increase the number of coating and drying cycles, resulting in poor productivity. On the other hand, if it exceeds 70 wt%, the amount of the solvent decreases, so that the fluidity of the ink is deteriorated and it becomes difficult to eject the ink. The phosphor ink may be ejected from the inkjet head a plurality of times by applying the phosphor once.

  Each phosphor ink of the present embodiment is, for example, a phosphor having an average particle diameter of 2 μm and containing 50 wt% phosphor, and a dispersant containing 0.5 wt% with respect to the weight of the phosphor. Further, butyl carbitol acetate and terpineol were used for each phosphor ink solution, and a binder such as ethyl cellulose was further added. At this time, when the viscosity of each phosphor ink was measured at 25 ° C., it was 20 mPa · s.

  Phosphor ink (droplet 303) ejected at a time is dropped into the discharge cell 11 from a nozzle hole 302 provided in the inkjet head 301. The volume of the droplet 303 is preferably less than 1/100 of the volume of the discharge cell 11.

  After each of the blue phosphor ink, the green phosphor ink, and the red phosphor ink is dropped on each discharge cell 11, each phosphor ink is heated to, for example, 80 ° C. or more to dry each phosphor ink. A drying process is performed. At this time, heating is performed at such a temperature that components such as the dispersant are not decomposed. Here, the heating temperature is determined largely depending on the component of the solvent used in each phosphor ink, the atmosphere, the exhaust speed, and the like.

  Next, a firing step is performed in which each phosphor ink is heated to 100 ° C. or higher. Thereby, the back plate of the PDP is completed. By performing this firing step, the diffused dispersant component can be sufficiently decomposed, so that the influence of the dispersant material on the PDP characteristics (for example, light emission luminance) can be reduced. The heating temperature in the firing step is determined largely depending on the components of the solvent used in each phosphor ink, the atmosphere, the exhaust speed, the decomposition temperature of additives, dispersants, and the like. The firing step may be performed at a temperature at which residual components such as additives and dispersants can be decomposed to the extent that they do not affect the characteristics of the PDP.

(Details of red phosphor ink application process)
Hereinafter, the application process of the red phosphor ink and the red phosphor ink will be described in more detail with reference to the drawings.

  FIG. 6 is a cross-sectional view for explaining the manufacturing method according to the present invention. As shown in FIG. 6A, after the partition wall 9 is formed, as shown in FIG. 6B, the phosphor ink 12 for forming the red phosphor layer 10 is ejected a plurality of times. Drop about 2/3 of the inner volume. In this case, the amount of ink dropped is adjusted in consideration of the wettability of the phosphor ink 12 in the material such as the back substrate 6.

FIG. 7 is a schematic diagram for explaining the dispersion state of the red phosphor in the red phosphor ink. FIG. 7A is a schematic diagram for explaining the dispersion state of the red phosphor in the red phosphor ink of the present embodiment. Dispersant 12b adheres to the surface of red phosphor particles 12a. Here, the red phosphor ink 12 has a red phosphor 12a content of 40 wt% or more and 70 wt% or less, and a specific surface area of the red phosphor 12 a of 1.0 m ² / g or more and 8.5 m. ² / g or less. The amount of dispersing agent 12b at this time, and calculates the total surface area from weight content of the red phosphor of the specific surface area and the ink of the red phosphor, the surface area 1 m ² per red phosphor 12a, 0.0001 g or 0.02g It is added within the following range. Note that the f content of the dispersant 12b in the phosphor ink corresponds to 0.04 to 1.4 wt%. As the dispersant, materials such as acrylic copolymers, alkylammonium salts, and siloxanes are used. As a solution of the red phosphor ink 12, butyl carbitol acetate or terpineol may be used, and a binder such as ethyl cellulose may be added as a viscosity adjusting agent for discharging by inkjet.

  Next, for example, the red phosphor ink is heated to 50 ° C. or higher and dried. At this time, overheating is performed at a temperature at which components such as the dispersant 12b do not decompose.

When the step is performed, when the dispersant 12b is less than 0.0007 g with respect to the surface area of 1 m ² of the red phosphor 12a, as shown in FIG. 7B, the surface area of the red phosphor particles 12a. Since the amount of the dispersing agent is small, an adsorption surface remains on the surface of the red phosphor particles 12a and aggregates between the red phosphor particles, resulting in a decrease in dispersibility. And as shown in FIG.8 (b), a red fluorescent substance cannot be made to adhere by the uniform thickness to the side surface of the partition 9 after a drying process. Further, if the dispersing agent 12b exceeds 0.04 g with respect to the surface area 1 m ² of the red phosphor 12a, the surface of the red phosphor particles 12a has no adsorption surface as shown in FIG. Agglomerates between various dispersants. And phosphor ink becomes easy to settle. And as shown in FIG.8 (c), it cannot adhere to the side surface of the partition 9 with sufficient adhesion amount after a drying process.

On the other hand, when the process is performed in the range where the amount of the dispersant added per 1 m ² of the surface area of the red phosphor is 0.0001 g or more and 0.02 g or less, as shown in FIG. The dispersion of the red phosphor 12a in the red phosphor ink is improved because the dispersant 12b is not insufficient or excessive, and therefore, as shown in FIG. The red phosphor can be attached to the side surface with a uniform thickness. Due to such a feature, even if it is a phosphor ink for ink jet having a low viscosity, or a phosphor ink containing phosphor particles having an average particle diameter of 1 μm or more with a fast sedimentation speed, the barrier ribs are used after the drying step. It becomes possible to make it adhere to the side surface of 9 with sufficient adhesion amount.

  Here, the heating temperature largely depends on the component of the solvent used in the phosphor ink 12, the atmosphere, the exhaust speed, and the like. Further, depending on the size and porosity of the pores present in the partition walls 9, the phosphor ink 12 is absorbed by the partition walls 9 by capillary action, so that it may not be necessary to perform overheating.

  Next, a phosphor ink baking process is performed by heating at 100 ° C. or higher to complete a PDP back plate. By performing this firing, the diffused dispersant component can be sufficiently decomposed, so that the influence on the device characteristics can be reduced.

  Here, the heating temperature largely depends on the components of the solvent used in the phosphor ink, the atmosphere, the exhaust speed, the decomposition temperature of the additive, dispersant, etc., and the residual components such as the additive, dispersant, etc. What is necessary is just to implement in the range which does not affect.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.

  FIG. 9 is a schematic diagram illustrating a configuration of a PDP apparatus 200 using the PDP 100. The PDP 100 is connected to the driving device 150 to constitute a PDP device. A display driver circuit 153, a display scan driver circuit 154, and an address driver circuit 155 are connected to the PDP 100. The controller 152 controls the application of these voltages. Address discharge is performed by applying a predetermined voltage to the scan electrode 2 and the data electrode 7 corresponding to the discharge cell to be lit. The controller 152 controls this voltage application. Thereafter, a sustain discharge is performed by applying a pulse voltage between the sustain electrode 3 and the scan electrode 2. Due to the sustain discharge, ultraviolet rays are generated in the discharge cells in which the address discharge has been performed. The discharge cell is turned on when the phosphor layer excited by the ultraviolet light emits light. An image is displayed by a combination of lighting and non-lighting of each color cell.

[Other Embodiments]
The embodiment has been described above. However, the present invention is not limited to these. Therefore, other embodiments of the present invention will be described collectively in this section.

(1)
Each phosphor ink may have a different average particle size and particle size distribution of the phosphor, solvent, additive, and component weight ratio.

(2)
The phosphor material used for each color is not limited to one type but may be a mixture of two or more types.

[Features of the embodiment]
Characteristic parts in the above embodiment are listed below. The invention included in the above embodiment is not limited to the following.

[C1]
The manufacturing method of the plasma display panel is as follows:
Forming partition walls (for example, partition walls 9) and forming a plurality of recesses (for example, discharge cells 11) separated by the partition walls;
Applying a phosphor ink to the recess using an inkjet device;
Have
The phosphor ink includes a red phosphor (for example, a red phosphor 12a) and a dispersant (for example, a dispersant 12b),
The amount of the dispersant added is 0.0001 g or more and 0.02 g or less per 1 m ² of the surface area of the red phosphor.

  Thereby, the manufacturing method of the plasma display panel with the favorable application | coating state of fluorescent substance can be provided.

[C2]
The method for producing a plasma display panel according to C1, wherein the phosphor has an average particle diameter of 1 μm or more.

  The phosphor having an average particle diameter of 0.001 μm to 1 μm described in Patent Document 1 needs to be reduced by pulverizing the phosphor or by screening the phosphor powder. When the phosphor is pulverized, the luminance may be lowered, and it is considered that the light emission characteristics of the plasma display panel cannot be satisfied. In addition, when the phosphor having an average particle size of less than 1.0 μm is selected by sieving, the yield is poor.

  On the other hand, if there is a particle having a large particle size, such as an ink containing phosphor particles having an average particle size of 1 μm or more, the droplet discharged from the nozzle is not stable. There is a higher possibility that it will be applied to the outside and the yield will be reduced.

  According to the C2 manufacturing method, a phosphor having sufficient luminance can be manufactured with a high yield using an ink jet apparatus.

[C3]
The method for manufacturing a plasma display panel according to C1 or C2, wherein the red phosphor has a specific surface area of 1.0 m ² / g or more and 8.5 m ² / g or less.

  Thereby, the influence of the amount of the dispersant on the ink physical properties (viscosity, surface tension, etc.) is small, and the phosphor ink can be efficiently discharged using the ink jet apparatus.

[C4]
The method for manufacturing a plasma display panel according to any one of C1 to C3, wherein a weight ratio of the red phosphor in the phosphor ink is 40 wt% or more and 70 wt% or less.

  Thereby, it can manufacture efficiently using an inkjet apparatus.

[C5]
The method for producing a plasma display panel according to any one of C1 to C4, wherein the phosphor ink has a viscosity at 25 ° C. of 10 mPa · s to 40 mPa · s. Thereby, it can suppress that each fluorescent substance particle precipitates and aggregates within an inkjet apparatus, and the discharge of the ink from the nozzle hole of an inkjet head becomes easy.

  As described above, the present invention is useful for easily realizing a high-definition PDP.

DESCRIPTION OF SYMBOLS 1 Front substrate 2 Scan electrode 3 Sustain electrode 4, 8 Dielectric layer 5 Protective layer 6 Back substrate 7 Data electrode 9 Partition 10 Phosphor layer 11 Discharge cell 12 Phosphor ink 12a Phosphor material 12b Dispersant 100 PDP
Reference Signs List 150 Drive Device 152 Controller 153 Display Driver Circuit 154 Display Scan Driver Circuit 155 Address Driver Circuit 200 PDP Device 301 Inkjet Head 302 Nozzle Hole 303 Droplet

Claims (5)

Forming a partition and forming a plurality of recesses separated by the partition;
Applying a phosphor ink to the recess using an inkjet device;
Have
The phosphor ink includes a red phosphor and a dispersant,
The amount of the dispersing agent added is 0.0001 g or more and 0.02 g or less per 1 m ² of the surface area of the red phosphor.
A method for manufacturing a plasma display panel. The phosphor has an average particle size of 1 μm or more,
The method for manufacturing a plasma display panel according to claim 1. The specific surface area of the red phosphor is 1.0 m ² / g or more and 8.5 m ² / g or less.
The manufacturing method of the plasma display panel of Claim 1 or 2. The weight ratio of the red phosphor in the phosphor ink is 40 wt% or more and 70 wt% or less.
The manufacturing method of the plasma display panel in any one of Claim 1 to 3. The phosphor ink has a viscosity at 25 ° C. of 10 mPa · s to 40 mPa · s.
The manufacturing method of the plasma display panel in any one of Claim 1 to 4.

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