JP2010102837A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma display panel with degradation of a protection layer or a phosphor prevented through substantial removal of water, and such impurity gas as hydrocarbon. <P>SOLUTION: The plasma display panel is provided with a front substrate 1 having display electrodes consisting of scanning electrodes 2 and sustaining electrodes 3 formed aligned in several columns, a dielectric layer 4 so as to cover the display electrodes, and a protective layer 5 formed on the dielectric layer 4, and a rear-face substrate 6 set in opposition to the front substrate 1 and having a plurality of data electrodes formed in a direction crossing the display electrodes with a discharge cell 11 formed at each crossing point. Further, it has a hydrogen-absorbing material 13 arranged containing palladium with an abundance ratio of: Pd<SP>2+</SP>/Pd0<SP>+</SP>≤0.9 inside. <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 that has caused the address discharge, and the phosphor layer of the corresponding discharge cell emits light to display an image. Do.

  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. Further, Patent Document 3 discloses alumina (Al ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ), lanthanum oxide (La ₂ O ₃ ), magnesium oxide (MgO), nickel oxide (NiO), and manganese oxide (MnO). , Oxides such as chromium oxide (CrO ₂ ), zirconium oxide (ZrO ₂ ), iron oxide (Fe ₂ O ₃ ), barium titanate (BaTiO ₃ ), titanium oxide (TiO ₂ ), etc. An attempt to remove hydrocarbon gas by placing an adsorbent added with a platinum group element as a decomposition catalyst in a region other than the image display region inside the PDP is described. In Patent Document 4, metal getters such as zircon (Zr), titanium (Ti), vanadium (V), aluminum (Al), and iron (Fe) are provided on the partition walls inside the PDP to absorb the organic solvent. An attempt to do is described.
JP 2003-303555 A JP-A-5-342991 International Publication No. 2005/086668 Pamphlet 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 these problems, and an object of the present invention 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.

In order to achieve this object, the present invention forms a display electrode composed of a scan electrode and a sustain electrode in a plurality of rows, forms a dielectric layer so as to cover the display electrode, and protects the dielectric layer on the dielectric layer. A front substrate having a layer formed thereon, and a rear substrate which is disposed to face the front substrate so as to form a discharge space, and which has a plurality of data electrodes formed in a direction intersecting the display electrodes to form discharge cells at the intersections. And a hydrogen storage material containing palladium having an abundance ratio of Pd ²⁺ / Pd0 ⁺ ≦ 0.9 is disposed inside.

  According to the present invention, there is provided a PDP in which impurities, such as water and hydrocarbons, are effectively and sufficiently removed from the two effects of adsorption and occlusion and the deterioration of the protective layer and the phosphor is suppressed. It becomes possible.

  FIG. 1 is an exploded perspective view showing a structure of a PDP in an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a main part of a discharge cell portion.

  As shown in FIG. 1, the PDP is composed of a front plate and a back plate arranged to face each other.

The front plate is formed by arranging a plurality of rows of display electrodes including a pair of scanning electrodes 2 and sustain electrodes 3 on a glass front substrate 1 in parallel with 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 and a protective layer 5 made of MgO are formed so as to cover the display electrodes. Scan electrode 2 and sustain electrode 3 are formed by forming bus electrodes 2b and 3b made of Ag on transparent electrodes 2a and 3a made of conductive metal oxide such as ITO, SnO ₂ , and ZnO, respectively.

  The back plate is formed on a glass back substrate 6 by forming a plurality of data electrodes 7 made of a conductive material composed mainly of mutually parallel Ag, and forming a dielectric layer 8 so as to cover the data electrodes 7. In addition, a grid-like partition wall 9 is formed thereon, and 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 wall 9. Yes.

  The front substrate 1 and the rear substrate 6 are arranged to face each other so that the scan electrode 2, the sustain electrode 3 and the data electrode 7 cross each other with a minute discharge space interposed therebetween, and the outer peripheral portion is sealed with a sealing material such as a frit. (Not shown) and bonded and sealed. A discharge gas containing, for example, xenon (Xe) or the like is sealed in the discharge space.

  The discharge space is divided into a plurality of sections by the barrier ribs 9, and discharge cells are formed at portions where the scan electrodes 2, the sustain electrodes 3, and the data electrodes 7 intersect. These discharge cells discharge and emit light to display an image.

Next, the material constituting the PDP will be described. The scanning electrode 2 is a wide transparent electrode made of a conductive metal oxide such as indium tin oxide (ITO), tin oxide (SnO ₂ ), or zinc oxide (ZnO). A narrow bus electrode 2b containing a metal such as silver (Ag) is laminated on 2a to increase conductivity. Similarly, the sustain electrode 3 is formed by laminating a narrow bus electrode 3b on a wide transparent electrode 3a. The dielectric layer 4 is made of bismuth oxide low melting glass or zinc oxide low melting glass. The protective layer 5 is a thin film layer made of an alkaline earth oxide mainly composed of magnesium oxide. The data electrode 7 is made of a highly conductive material containing a metal such as silver. The dielectric layer 8 may be made of the same material as that of the dielectric layer 4, but may be made of a material in which titanium oxide particles are mixed so as to also serve as a visible light reflecting layer. The partition wall 9 is formed using, for example, a low-melting glass material. The phosphor layer 10 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.

  FIG. 3 is an electrode array diagram of the PDP in the embodiment of the present invention. 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 direction. M data electrodes A1... Am (7 in FIG. 1) which are long in the direction are arranged. Discharge cells 11 are formed at the intersections of the pair of scan electrodes Y1 and sustain electrodes X1 and one data electrode A1, and m × n discharge cells 11 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.

  Here, as shown in FIG. 2, in the discharge space sandwiched between the front plate and the back plate, the scan electrode 2, the sustain electrode 3, and the data electrode 7 face each other, and a discharge cell is formed in a portion surrounded by the barrier ribs 9. 11 is formed, and a gap between the scan electrode 2 and the sustain electrode 3 in the discharge cell 11 becomes a discharge gap. The scan electrodes 2 and the sustain electrodes 3 are formed so that the scan electrodes 2 and the sustain electrodes 3 are adjacent to each other between the adjacent discharge cells 11, and between the scan electrodes 2 and the sustain electrodes 3. A black stripe 12 which is a light shielding layer made of a black material is formed therebetween.

  In the present embodiment, the hydrogen storage material 13 containing palladium that selectively stores hydrogen is disposed on the protective layer 5 of the front substrate 1 in a portion corresponding to the black stripe 12. The hydrogen storage material 13 does not interfere with the discharge phenomenon. In addition, what is necessary is just to arrange | position the hydrogen storage material 13 containing this palladium inside a panel, for example, you may arrange | position on the surface of the fluorescent substance layer 10 or the protective layer 5. FIG.

  The hydrogen storage material 13 for storing hydrogen is at least one of platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), iridium (Ir), and osmium (Os). Platinum group powders can be used, but those containing palladium are desirable. As the hydrogen storage material 13, any one or more of platinum, palladium, ruthenium, rhodium, iridium, and osmium and transition metals such as titanium (Ti), manganese (Mn), zirconium (Zr), and nickel (Ni) are used. Further, a compound with any one of cobalt (Co), lanthanum (La), iron (Fe), and vanadium (V) can be used. In this case, an alloy containing palladium is also desirable.

  As a method of dispersing the hydrogen storage material 13 in the portion corresponding to the black stripe 12 on the protective layer 5, for example, printing is performed by screen printing and drying, and then baking is performed simultaneously with the material of the protective layer 5. The particle size of the hydrogen storage material 13 is desirably 0.1 μm to 5 μm. Further, the coverage is preferably 1% or more. When the particle size is increased, even if the particles are dispersed at an equivalent coverage, the total surface area of the dispersed particles is remarkably reduced, and the amount of occlusion is reduced under the environment in the panel. It will not work effectively. Similarly, if the coverage is not 1% or more, the total surface area of the dispersed particles is remarkably reduced, and the amount of occlusion is reduced under the environment in the panel. Stop working.

In addition, the film thickness of the dielectric layer 4 of PDP in this Embodiment mentioned above is 40 micrometers, for example, and the film thickness of the protective layer 5 is 0.8 micrometers, for example. Further, the height of the partition wall 9 is, for example, 0.12 mm, and the thickness of the phosphor layer 10 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 hydrogen storage material 13 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 rib, phosphor layer, etc. by discharging the PDP, and the water molecules and hydrocarbon molecules therein are decomposed into hydrogen atoms, oxygen atoms, and carbon atoms. I noticed that. Focusing on the fact that platinum group elements have the property of occluding a large amount of hydrogen, we thought that by removing hydrogen atoms with a small radius in platinum group elements, water and hydrocarbons could be removed as a result. .

  Therefore, the present inventors have developed a powder of platinum group elements (platinum, palladium, ruthenium, rhodium, iridium, osmium), or platinum group elements and transition metals (titanium, manganese, zirconium, nickel, cobalt, lanthanum, iron, A PDP in which an alloy powder with vanadium was applied on the protective layer on the top of the IPG using a printing method or the like was produced.

  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 “smudge” and “burn-in” was reduced. In particular, when powder containing palladium was used, it was confirmed that the image quality deterioration hardly occurred. Further, it was confirmed that when the powder containing palladium was used, the light emission luminance of the phosphor hardly decreased. This is because water molecules and hydrocarbon molecules are decomposed into hydrogen atoms, oxygen atoms, and carbon atoms, and platinum group elements, particularly palladium, occlude a large amount of hydrogen. This is thought to be due to a significant decrease in hydrocarbon molecules.

  As is clear from this experiment, when platinum group elements, particularly palladium, are used as the hydrogen storage material, water molecules and hydrocarbon molecules can be greatly reduced in order to store hydrogen decomposed by discharge. It has been found that the discharge characteristics can be stabilized, the change with time can be suppressed, and in addition, the luminance reduction of the phosphor can be suppressed.

  Further, the occlusion ability of the hydrogen occlusion material depends on the oxidation-reduction state of the platinum group, and it has been found that if it is oxidized too much, the occlusion amount of impure gas is greatly reduced and the material does not work effectively.

Therefore, as a result of experiments and studies conducted by the present inventors, a hydrogen storage material containing palladium having an abundance ratio of Pd ²⁺ / Pd0 ⁺ ≦ 0.9, which is fired in an N ₂ atmosphere or at a low temperature, inside the panel. It has been found that by arranging 13, the hydrogen storage ability can be most efficiently operated and impurities such as water and hydrocarbons can be sufficiently removed. As for the palladium abundance ratio, it was found that the hydrogen storage material 13 containing palladium having an abundance ratio of Pd ²⁺ / Pd0 ⁺ ≦ 0.26 or less was particularly desirable.

As described above, according to the present invention, the hydrogen storage material 13 containing palladium having an abundance ratio of Pd ²⁺ / Pd0 ⁺ ≦ 0.9 fired in an N ₂ atmosphere or at a low temperature is disposed inside the panel. By doing so, water molecules and hydrocarbon molecules can be greatly reduced to absorb hydrogen decomposed with discharge, stabilizing discharge characteristics, suppressing changes over time, and adding to the brightness of the phosphor. The decrease can be suppressed.

  The specific numerical values and the like used in the above embodiment are merely examples, and it is desirable to set them to optimal values as appropriate according to the specifications of the PDP and the specifications of the PDP material.

  As described above, the present invention is useful as an invention that can provide a PDP that can sufficiently remove impurities such as water and hydrocarbons and can suppress deterioration of the protective layer and the phosphor.

The disassembled perspective view which shows the structure of PDP in embodiment of this invention Sectional drawing which shows the discharge cell part of PDP in embodiment of this invention The figure which shows the electrode arrangement | sequence of PDP in embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front substrate 2 Scan electrode 2a, 3a Transparent electrode 2b, 3b Bus electrode 3 Sustain electrode 4 Dielectric layer 5 Protective layer 6 Back substrate 7 Data electrode 8 Dielectric layer 9 Partition 10 Phosphor layer 11 Discharge cell 12 Black stripe 13 Hydrogen Occlusion material

Claims (1)

A front substrate in which a plurality of rows of display electrodes including scan electrodes and sustain electrodes are arranged and a dielectric layer is formed so as to cover the display electrodes, and a protective layer is formed on the dielectric layer, and the front substrate And a back substrate having a plurality of data electrodes formed in a direction intersecting with the display electrodes and forming discharge cells at the intersecting portions, and Pd ²⁺ / Pd0 inside. ⁺ A plasma display panel comprising a hydrogen storage material containing palladium having an abundance ratio of ≦ 0.9.

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