JP2010092749A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PDP in which impurity gas such as water and hydrocarbon is sufficiently removed, and deterioration of a protective layer and a phosphor is suppressed. <P>SOLUTION: This includes a front face substrate 21 in which a plurality of display electrode pairs, a dielectric layer 25, and the protective layer 26 are formed, and a rear face substrate 31 in which a plurality of data electrodes, a barrier rib 34, and a phosphor layer 35 are formed. The front face substrate 21 and the rear face substrate 31 are constituted to be oppositely arranged so that the display electrode pairs and the data electrodes cross each other, and a photocatalyst material 38 inside of which palladium is carried on one part of anatase-type titanium dioxide is arranged. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plasma display panel used for image display.

  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.

  A typical AC surface discharge type PDP as a PDP has a large number of discharge cells formed between a front substrate and a rear substrate which are arranged to face each other. In the front substrate, a plurality of display electrode pairs each consisting of a pair of scan electrodes and sustain electrodes are formed in parallel on a glass substrate, and a dielectric layer and a protective layer are formed so as to cover the display electrode pairs. . Here, the protective layer is a thin film of an alkaline earth oxide such as magnesium oxide (MgO), and is provided to protect the dielectric layer from ion sputtering and to stabilize discharge characteristics such as a discharge start voltage. The back substrate is formed with a plurality of parallel data electrodes on a glass substrate, a dielectric layer so as to cover them, and a grid-like partition wall formed thereon, respectively, and the surface of the dielectric layer and the side surface of the partition wall A phosphor layer is formed on the substrate. Then, the front substrate and the rear substrate are disposed opposite to each other so that the display electrode pair and the data electrode are three-dimensionally crossed and sealed, and a discharge gas is sealed in the internal discharge space. Here, a discharge cell is formed at a portion where the display electrode pair and the data electrode face each other. Ultraviolet light is generated by gas discharge in each discharge cell of the PDP having such a configuration, and phosphors of red, green, and blue colors are excited and emitted by the ultraviolet light to perform color display.

  As a method of driving the PDP, a subfield method, that is, a method of performing gradation display by combining subfields to emit light after dividing one field period into a plurality of subfields. The subfield has an initialization period, an address period, and a sustain period. In the initializing period, initializing discharge is generated in each discharge cell, and wall charges necessary for the subsequent address discharge are formed. In the address period, address discharge is selectively generated in the discharge cells to be displayed, and wall charges necessary for the subsequent sustain discharge are formed. In the sustain period, a sustain pulse is alternately applied to the scan electrode and the sustain electrode, a sustain discharge is generated in the discharge cell in which the address discharge has occurred, and the phosphor layer of the corresponding discharge cell is caused to emit light by ultraviolet light. Display an image.

  The PDP is manufactured through a front substrate manufacturing process, a back substrate manufacturing process, a sealing process, an exhaust process, and a discharge gas supply process. Here, the sealing step is a step of bonding the front substrate produced in the front substrate production step and the rear substrate produced in the back substrate production step, and the exhausting step is a step of exhausting gas from the space inside the PDP. In the sealing step, since the front substrate and the rear substrate are bonded together using frit, they are superposed and fired at a temperature equal to or higher than the softening point temperature of the frit, for example, about 440 ° C. to 500 ° C.

At this time, impure gases such as water (H ₂ O), carbon dioxide (CO, CO ₂ ), and hydrocarbons (C _n H _m ) are discharged from the frit and the like, and some of these impure gases are adsorbed inside the PDP. Is done. In addition, although the impure gas is exhausted together with the air inside the PDP in the subsequent exhaust process, it is difficult to exhaust completely including the impure gas adsorbed inside the PDP, and a certain amount of impure gas remains inside the PDP. That was inevitable. In addition, with the recent increase in screen size and resolution of PDPs, the residual amount of impure gas tends to increase.

  However, it is known that materials such as a protective layer and a phosphor react with an impure gas to deteriorate its characteristics. In particular, a large amount of water remaining inside the PDP adversely affects the discharge characteristics of the protective layer, lowers the discharge start voltage of the discharge cells, and causes a “bleeding” image quality deterioration on the display screen. However, when a still image is displayed for a long time, there is a problem that “burn-in” occurs in which the image becomes an afterimage. Hydrocarbons also have problems such as reducing the surface of the phosphor and lowering the emission luminance of the phosphor.

Therefore, it is one of the important issues to reduce the impurity gases remaining in the PDP, particularly water and hydrocarbons, stabilize the discharge characteristics, and suppress the change with time. As a method for removing these impure gases, for example, Patent Document 1 discloses an attempt to remove water by disposing an adsorbent such as crystalline aluminosilicate, γ-activated alumina or amorphous activated silica inside the PDP. Has been. Patent Document 2 describes an attempt to remove water by providing a magnesium oxide film in a region other than the image display region inside the PDP. In Patent Document 3, a metal getter such as zircon (Zr), titanium (Ti), vanadium (V), aluminum (Al), or iron (Fe) is provided on a partition inside the PDP to absorb an organic solvent. An attempt to do is described.
JP 2003-303555 A JP-A-5-342991 Japanese Patent Laid-Open No. 2002-531918

  However, despite the various attempts described above, it is difficult to sufficiently remove impurities such as water, hydrocarbons, and organic solvents, and it is difficult to suppress deterioration of the protective layer and the phosphor.

  The present invention has been made in view of such a current situation, and an object thereof is to provide a PDP in which impurity gases such as water and hydrocarbons are sufficiently removed and deterioration of a protective layer and a phosphor is suppressed.

  To achieve this object, the PDP of the present invention includes a front substrate on which a plurality of display electrode pairs, a dielectric layer, and a protective layer are formed, and a back surface on which a plurality of data electrodes, barrier ribs, and a phosphor layer are formed. A front substrate and the rear substrate so that the display electrode pair and the data electrode intersect with each other, and palladium is formed on a part of the anatase-type titanium dioxide inside. The supported photocatalytic material is arranged. With this configuration, it is possible to provide a PDP in which impurity gases such as water and hydrocarbons are sufficiently removed and deterioration of the protective layer and the phosphor is suppressed.

  In the PDP of the present invention, a photocatalytic material in which palladium is supported on a part of anatase-type titanium dioxide may be disposed on the phosphor layer or inside the phosphor layer.

  In the PDP of the present invention, a photocatalytic material in which palladium is supported on a part of anatase-type titanium dioxide may be disposed on the surface of the partition wall or inside the partition wall.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide PDP which fully removed impurity gases, such as water and a hydrocarbon, and suppressed degradation of a protective layer and fluorescent substance.

  Hereinafter, a PDP according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is an exploded perspective view showing a schematic structure of a PDP according to Embodiment 1 of the present invention. The PDP 10 is configured by bonding a glass front substrate 21 and a back substrate 31 together. On the front substrate 21, a plurality of display electrode pairs 24 including scan electrodes 22 and sustain electrodes 23 are formed. A dielectric layer 25 is formed so as to cover the display electrode pair 24, and a protective layer 26 is formed on the dielectric layer 25. A plurality of data electrodes 32 are formed on the back substrate 31, a dielectric layer 33 is formed so as to cover the data electrodes 32, and a grid-like partition wall 34 is formed thereon. A phosphor layer 35 that emits red, green, and blue light is applied on the side surfaces of the partition walls 34 and the dielectric layer 33.

  In the first embodiment, a photocatalytic material in which palladium is supported on a part of anatase-type titanium dioxide is disposed on the phosphor layer 35. FIG. 2 is a cross-sectional view showing a schematic structure of the PDP according to Embodiment 1 of the present invention. Palladium is supported on a part of anatase-type titanium dioxide on the phosphor layer 35 applied on the back substrate 31. A state in which the powder made of the photocatalyst material 38 is dispersed is schematically shown. The photocatalytic material 38 in which palladium is supported on a part of anatase-type titanium dioxide has a covering rate of 50% or less so as not to disturb the light emission of the phosphor.

  FIG. 2 schematically shows a state where the photocatalytic material 38 in which palladium is supported on a part of anatase-type titanium dioxide is dispersed so as to be scattered on the surface (surface) of the phosphor layer 35. However, the same effect can be obtained by dispersing the photocatalytic material 38 in which palladium is supported on a part of anatase-type titanium dioxide in the phosphor layer 35.

  The front substrate 21 and the rear substrate 31 are arranged to face each other so that the display electrode pair 24 and the data electrode 32 intersect with each other with a minute discharge space interposed therebetween, and a sealing material (not shown) such as a frit is provided on the outer periphery. Z)). A discharge gas containing, for example, xenon (Xe) or the like is sealed in the discharge space. The discharge space is partitioned into a plurality of sections by partition walls 34, and discharge cells are formed at the intersections between the display electrode pairs 24 and the data electrodes 32. These discharge cells discharge and emit light to display an image. Note that the structure of the PDP 10 is not limited to that described above. For example, the dielectric layer 33 may be omitted, and the shape of the partition wall 34 may be a stripe shape.

Next, the material of the PDP 10 will be described. The scanning electrode 22 is formed on a wide transparent electrode 22a made of a conductive metal oxide such as indium tin oxide (ITO), tin oxide (SnO ₂ ), or zinc oxide (ZnO), in order to increase conductivity. A narrow bus electrode 22b containing a metal such as (Ag) is laminated. Similarly, the sustain electrode 23 is formed by laminating a narrow bus electrode 23b on a wide transparent electrode 23a. The dielectric layer 25 is made of bismuth oxide low melting glass or zinc oxide low melting glass. The protective layer 26 is a thin film layer made of an alkaline earth oxide mainly composed of magnesium oxide. The data electrode 32 is made of a highly conductive material containing a metal such as silver. The partition wall 34 is formed using, for example, a low melting point glass material. The phosphor layer 35 can use BaMgAl ₁₀ O ₁₇ : Eu as a blue phosphor, Zn ₂ SiO ₄ : Mn as a green phosphor, and (Y, Gd) BO ₃ : Eu as a red phosphor. Of course, the phosphor is not limited to the above phosphor.

  In the first embodiment, the photocatalytic material 38 in which palladium is supported on a part of anatase type titanium dioxide is used. Instead of palladium, platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium One or more platinum groups of (Ir) and osmium (Os) can be used, but palladium is particularly desirable.

  As a method for dispersing the photocatalytic material 38 in which palladium is supported on a part of anatase-type titanium dioxide on the phosphor layer 35, for example, a spray method can be used. As a method for dispersing the photocatalytic material 38 in which palladium is supported on a part of anatase-type titanium dioxide in the phosphor layer 35, palladium is supported on a part of anatase-type titanium dioxide in advance when the phosphor layer 35 is formed. The photocatalytic material 38 may be mixed.

Note that the film thickness of the dielectric layer 25 of the PDP 10 in the present embodiment described above is, for example, 40 μm, and the film thickness of the protective layer 26 is, for example, 0.8 μm. Further, the height of the partition wall 34 is, for example, 0.12 mm, and the thickness of the phosphor layer 35 is, for example, 15 μm. The discharge gas is, for example, a mixed gas of neon (Ne) and xenon (Xe), the gas pressure of the discharge gas is, for example, 6 × 10 ⁴ Pa, and the xenon content is, for example, 10% by volume or more.

  Next, the function of the photocatalytic material 38 in which palladium is supported on a part of anatase type titanium dioxide will be described. Conventionally, metal getters and oxide getters have been used to remove water and hydrocarbons, but these impure gases have large molecular diameters, so they do not penetrate well into the getter and limit the amount of impure gas adsorbed. was there.

  The present inventors discharge impure gas from the protective layer, barrier ribs, phosphor layers, etc. by discharging the PDP, and water molecules and hydrocarbon molecules therein generate hydrogen atoms, oxygen atoms by ultraviolet rays generated by the discharge. We focused on photolysis into atoms and carbon atoms. Therefore, by placing a platinum group such as anatase-type titanium dioxide or palladium with photocatalytic action in the vicinity of the discharge, photolysis of water molecules and hydrocarbon molecules is promoted, and almost completely converted to hydrogen atoms, oxygen atoms, and carbon atoms. I thought it would be broken down. Attention was also paid to the fact that platinum group elements have the property of occluding a large amount of hydrogen, and it was thought that water and hydrocarbons could be removed as a result of occluding platinum atoms with small radius hydrogen atoms. .

  Therefore, the present inventors paid attention to a photocatalytic material in which palladium is supported on a part of anatase-type titanium dioxide composed of anatase-type titanium dioxide and palladium, and the powder is printed, sprayed, photolithography, dispenser A PDP coated on the phosphor layer, the top of the partition walls, the protective layer, and the like was prepared using a method, an ink jet method, or the like. Anatase-type titanium dioxide and white metal element powder were used as a paste by kneading with an organic binder as required. In addition, the place where the anatase type titanium dioxide and the white metal element are applied is a place where electric discharge is generated at the time of displaying an image of the PDP or the vicinity thereof.

  Images were displayed using the PDP produced in this manner, and the presence or absence of “bleeding” and “burn-in” was visually confirmed for about 1000 hours. As a result, it was confirmed that image quality deterioration due to “smear” and “burn-in” was reduced. It was also confirmed that these image quality deterioration and emission luminance decrease hardly occur. This is because the photolysis of water molecules and hydrocarbon molecules is promoted sufficiently, almost completely decomposed into hydrogen atoms, oxygen atoms, and carbon atoms, and platinum group elements occlude a large amount of hydrogen. Is considered to be due to a significant decrease in water molecules and hydrocarbon molecules having a molecular weight larger than that of the simple substance.

  As is clear from this experiment, when a photocatalytic material in which palladium is supported on a part of anatase-type titanium dioxide is used, impurities such as moisture and hydrocarbon gas emitted from a protective layer, partition walls, phosphor layers, etc. Most of them are photolyzed with discharge, and the generated hydrogen is occluded by the platinum group such as palladium, so that water molecules and hydrocarbon molecules can be greatly reduced, stabilizing discharge characteristics and suppressing changes over time. In addition, it is possible to suppress a decrease in luminance of the phosphor.

  In the first embodiment, the photocatalytic material in which palladium is supported on a part of anatase-type titanium dioxide is dispersed on the surface or inside of the phosphor layer 35. However, the present invention is not limited to this. .

  Therefore, an embodiment in which a photocatalytic material 38 in which palladium is supported on a part of anatase-type titanium dioxide is disposed in another place will be described below.

(Embodiment 2)
The PDP according to the second embodiment is different from the first embodiment in that a photocatalytic material 38 in which palladium is supported on a part of anatase type titanium dioxide is disposed on the surface of the partition wall 34, particularly on the top of the partition wall 34. . FIG. 3 is a cross-sectional view showing a schematic structure of the PDP 10 according to the second embodiment of the present invention, in which a photocatalytic material 38 in which palladium is supported on a part of anatase-type titanium dioxide is arranged on the top of the partition wall FIG.

  In the second embodiment, the photocatalytic material 38 in which palladium is supported on a part of the anatase type titanium dioxide is disposed at the top of the partition wall 34, but the anatase type titanium dioxide is formed on the surface of the partition wall 34 other than the top part of the partition wall 34. A photocatalytic material 38 on which palladium is supported may be disposed on a part of the photocatalyst. When the partition wall 34 has a porous structure, the same effect can be obtained even when the photocatalytic material 38 in which palladium is supported on a part of anatase-type titanium dioxide is present inside the partition wall 34.

(Embodiment 3)
The PDP in the third embodiment is different from the first embodiment in that a photocatalytic material 38 in which palladium is supported on a part of anatase-type titanium dioxide is disposed on the protective layer 26 of the front substrate 21. FIG. 4 is a cross-sectional view showing a schematic structure of PDP 10 according to Embodiment 3 of the present invention, in which a photocatalytic material 38 in which palladium is supported on a part of anatase-type titanium dioxide is dispersed on protective layer 26. FIG.

  As described above in Embodiments 1 to 3, in Embodiments 1 to 3, the photocatalytic material 38 in which palladium is supported on a part of anatase-type titanium dioxide containing palladium is disposed inside the PDP. . In the first to third embodiments, a part of anatase-type titanium dioxide having functions of a photocatalyst and occluded hydrogen is used instead of reducing an impure gas having a large molecular diameter such as water molecules and hydrocarbon molecules as it is. Most of the water and hydrocarbon gas are photodecomposed with discharge by the photocatalyst material 38 on which palladium is supported, and the produced hydrogen is occluded in large quantities by palladium, so that water and hydrocarbons are greatly reduced. As a result, it is possible to stabilize the discharge characteristics, suppress a change with time, and suppress a decrease in luminance of the phosphor.

  It should be noted that the specific numerical values used in the first to third embodiments are merely examples, and it is desirable to appropriately set the optimal values according to the specifications of the PDP and the specifications of the PDP material. .

  As described above, the present invention is useful for providing a large-screen, high-definition PDP.

1 is an exploded perspective view showing a schematic structure of a PDP according to Embodiment 1 of the present invention. Sectional drawing which shows schematic structure of PDP by Embodiment 1 of this invention Sectional drawing which shows schematic structure of PDP by Embodiment 2 of this invention Sectional drawing which shows schematic structure of PDP by Embodiment 3 of this invention

Explanation of symbols

10 Plasma display panel (PDP)
21 Front substrate 22 Scan electrode 23 Sustain electrode 24 Display electrode pair 25 Dielectric layer 26 Protective layer 31 Back substrate 32 Data electrode 33 Dielectric layer 34 Partition 35 Phosphor layer 38 Palladium was supported on a part of anatase type titanium dioxide Photocatalytic material

Claims (3)

A front substrate on which a plurality of display electrode pairs, a dielectric layer, and a protective layer are formed; and a rear substrate on which a plurality of data electrodes, barrier ribs, and phosphor layers are formed, and the display electrode pair and the data The front substrate and the back substrate are arranged to face each other so that the electrodes intersect with each other, and a photocatalytic material in which palladium is supported on a part of anatase-type titanium dioxide is arranged inside. Plasma display panel. The plasma display panel according to claim 1, wherein a photocatalytic material in which palladium is supported on a part of the anatase-type titanium dioxide is disposed on the phosphor layer or inside the phosphor layer. The plasma display panel according to claim 1, wherein a photocatalytic material in which palladium is supported on a part of the anatase-type titanium dioxide is disposed on the surface of the partition wall or inside the partition wall.

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