JP2011124065A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PDP with high reliability that prevents a protective layer and a phosphor restrained from degradation by fully removing moisture, and impurity gas such as hydrocarbon. <P>SOLUTION: The PDP is provided with a front substrate 11 with a plurality of display electrode pairs 14, dielectric layers 15 and protective layers 16 formed in parallel with each other, a back substrate 17 with a plurality of data electrodes 18, base dielectric layers 19, barrier ribs 22 and phosphor layers 23 formed in parallel with each other, with the front substrate 11 and the back substrate 17 set in opposition with the surroundings sealed so as the display electrode pairs 14 and the data electrodes 18 to cross each other. A hydrogen storage material 20 made of a platinum group element and an oxygen storage material 21 containing at least one out of iron, vanadium, aluminum, and titanium are arranged inside the PDP. <P>COPYRIGHT: (C)2011,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. . The back substrate is formed of 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 And a phosphor layer.

  The front substrate and the rear substrate are arranged opposite to each other so that the display electrode pair and the data electrode intersect with each other 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 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.

In such a sealing process, impure gases such as water (H ₂ O), carbon monoxide (CO), carbon dioxide (CO ₂ ), and hydrocarbon (C _n H _m ) are discharged from the frit. A part of the impure gas is adsorbed inside the PDP. In the subsequent exhaust process, the internal space of the PDP is exhausted. However, it is difficult to completely exhaust the impure gas adsorbed inside the PDP, and a certain amount of impure gas remains inside the PDP.

It is known that the protective layer, the phosphor, and the like react with these impure gases to deteriorate their characteristics. In particular, water (H ₂ O) affects the protective layer, lowers the discharge start voltage of the discharge cells, and causes “bleeding” image quality degradation on the display screen. In addition, when a still image is displayed for a long time, “burn-in” occurs in which the image becomes an afterimage. Further, the hydrocarbon reduces the surface of the phosphor and lowers the emission luminance of the phosphor.

Therefore, it is important to reduce the impurity gas remaining in the inside of the PDP, particularly water and hydrocarbons, stabilize the discharge characteristics, suppress the change over time, and improve the reliability. As methods for removing these impure gases, for example, Patent Document 1 discloses crystalline aluminosilicate (xM ₂ O.yM ₂ O.yAl ₂ O ₃ .zSiO ₂ .nH ₂ O), γ-activated alumina (γ-Al An example is disclosed in which an adsorbent such as ₂ O ₃ ) or amorphous activated silica (SiO ₂ ) is placed inside the PDP to remove water. Patent Document 2 discloses an example in which a magnesium oxide film is provided outside the image display area inside the PDP to remove water.

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 ), and carbonization of these oxides An example in which an adsorbent to which a platinum group element as a hydrogen decomposition catalyst is added is disposed outside the image display area inside the PDP to remove hydrocarbons is disclosed. In Patent Document 4, metal getters such as zircon (Zr), titanium (Ti), vanadium (V), aluminum (Al), and iron (Fe) are provided on the partition inside the PDP to adsorb organic solvent components. An example is disclosed.

JP 2003-303555 A JP-A-5-342991 International Publication No. 2005/086668 JP 2002-531918 A

  However, with the recent increase in screen size and definition of PDPs, the residual amount of impure gas increases. Therefore, in the above conventional example, it is difficult to sufficiently remove impurities such as water, hydrocarbons, and organic solvents, and there is a problem that the protective layer and the phosphor are deteriorated.

  An object of the present invention is to solve these problems and to provide a highly reliable PDP in which impurities such as water and hydrocarbons are sufficiently removed and deterioration of a protective layer and a phosphor is suppressed.

  In order to achieve the above 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 that are parallel to each other, a plurality of data electrodes that are parallel to each other, and a base dielectric. The PDP has a back substrate on which a layer, a barrier rib, and a phosphor layer are formed, and the front substrate and the back substrate are arranged opposite to each other so that the display electrode pair and the data electrode intersect and sealed. In the PDP, a hydrogen storage material made of a platinum group element and an oxygen storage material containing at least one of zirconium, iron, vanadium, aluminum, and titanium are arranged.

  According to such a configuration, since the oxygen storage material keeps the inside of the PDP in a reducing atmosphere and prevents the oxidation of the hydrogen storage material, the hydrogen storage capacity of the hydrogen storage material is increased. Can be sufficiently removed, and a highly reliable PDP in which deterioration of the protective layer and the phosphor is suppressed can be realized.

  The hydrogen storage material may be palladium. According to such a configuration, palladium has the highest hydrogen storage capacity among the platinum group elements, so placing palladium inside the PDP causes image quality degradation such as “smudge” and “burn-in”, and phosphor emission. It is possible to realize a PDP that hardly causes a decrease in luminance.

  Alternatively, the oxygen storage material may be two or more alloy powders of zirconium, iron, vanadium, aluminum, and titanium whose surfaces are nitrided or oxidized. According to such a configuration, the oxygen storage material can be easily handled at room temperature.

  An oxygen storage material may be disposed on the surface of the phosphor layer. According to such a configuration, since the opportunity for the oxygen storage material to be heated in the PDP manufacturing process can be minimized, it is possible to prevent a decrease in the oxygen storage capacity of the oxygen storage material.

  Further, an oxygen storage material may be disposed on the surface of the protective layer. According to such a configuration, since the opportunity for the oxygen storage material to be heated in the PDP manufacturing process can be minimized, it is possible to prevent a decrease in the oxygen storage capacity of the oxygen storage material.

  According to the PDP of the present invention, it is possible to provide a highly reliable PDP in which impurities such as water and hydrocarbons are sufficiently removed and deterioration of the protective layer and the phosphor is suppressed.

3 is an exploded perspective view showing a structure of a PDP in Embodiment 1. FIG. It is the sectional view on the AA line of FIG. 3 is a diagram showing an electrode arrangement of the PDP in Embodiment 1. FIG. 6 is a cross-sectional view of a PDP in a second embodiment. FIG.

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

(Embodiment 1)
FIG. 1 is an exploded perspective view showing the structure of the PDP in Embodiment 1, and FIG. 2 is a cross-sectional view taken along line AA in FIG. As shown in FIGS. 1 and 2, the PDP 10 includes a front substrate 11 and a back substrate 17.

1 and 2, a plurality of pairs of display electrodes 14 are formed on a glass front substrate 11 in parallel with each other by a scan electrode 12 and a sustain electrode 13. Scan electrode 12 and sustain electrode 13 are formed in a pattern that repeats in the arrangement of scan electrode 12 -sustain electrode 13 -sustain electrode 13 -scan electrode 12. The scanning electrode 12 is formed on a wide transparent electrode 12a 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 12b containing a metal such as (Ag) is stacked. Similarly, the sustain electrode 13 is formed by laminating a narrow bus electrode 13b on a wide transparent electrode 13a.

Further, a dielectric layer 15 and a protective layer 16 made of magnesium oxide (MgO) are formed so as to cover the display electrode pair 14. The dielectric layer 15 is made of bismuth oxide (Bi ₂ O ₃ ) -based low melting glass or zinc oxide (ZnO) -based low melting glass having a thickness of about 40 μm. The protective layer 16 is a thin film layer made of an alkaline earth oxide mainly composed of magnesium oxide (MgO) having a film thickness of about 0.8 μm. The protective layer 16 protects the dielectric layer 15 from ion sputtering and discharge start voltage, etc. It is provided to stabilize the discharge characteristics.

A plurality of parallel data electrodes 18 made of a highly conductive material mainly composed of silver (Ag) or the like are formed on the glass back substrate 17, and a base dielectric layer is formed so as to cover the data electrodes 18. 19 is formed. The underlying dielectric layer 19 may be bismuth oxide (Bi ₂ O ₃ ) -based low-melting glass similar to that of the dielectric layer 15, but titanium oxide (TiO ₂₎ so as to also serve as a visible light reflecting layer. ) A material in which particles are mixed may be used.

A grid-like barrier rib 22 is formed on the base dielectric layer 19, and phosphor layers 23 that emit red, green, and blue light are formed on the surface of the base dielectric layer 19 and the side surfaces of the barrier rib 22. . The partition wall 22 is formed to a height of about 0.12 mm using, for example, a low-melting glass material. The phosphor layer 23 is about 15 μm using BaMgAl ₁₀ O ₁₇ : Eu as a blue phosphor, Zn ₂ SiO ₄ : Mn as a green phosphor, (Y, Gd) BO ₃ : Eu as a red phosphor, and the like. The film thickness is formed.

  As shown in FIG. 2, a hydrogen storage material 20 made of a single crystal platinum group element having a particle size of 0.1 μm to 20 μm is dispersed and arranged on the surface of the phosphor layer 23. Details of the hydrogen storage material 20 will be described later.

The front substrate 11 and the rear substrate 17 are arranged to face each other so that the display electrode pair 14 and the data electrode 18 cross each other, and the outer peripheral portion thereof is sealed with a sealing material (not shown) such as a frit and discharged inside. A space is formed. A discharge gas containing xenon (Xe) or the like is sealed in the discharge space at a pressure of about 6 × 10 ⁴ Pa. The discharge space is partitioned into a plurality of sections by partition walls 22, and discharge cells 24 are formed at the intersections between the display electrode pairs 14 and the data electrodes 18. These discharge cells 24 discharge and emit light to display an image. The structure of the PDP 10 is not limited to that described above, and the shape of the partition wall 22 may be a stripe shape.

  FIG. 3 is an electrode array diagram of PDP 10 in the first exemplary embodiment. N scanning electrodes Y1, Y2, Y3... Yn (scanning electrode 12 in FIG. 1) and n sustaining electrodes X1, X2, X3... Xn (sustaining electrode 13 in FIG. 1) are long in the row direction. Arranged are m data electrodes A1... Am (data electrodes 18 in FIG. 1) that are long in the column direction. Discharge cells 24 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 24 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 substrate 11 and the rear substrate 17.

  A general method for driving the PDP 10 is a subfield method, that is, a method in which gradation display is performed by combining one subfield 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 24 to form wall charges necessary for the subsequent address discharge. In the address period, address discharge is selectively generated in the discharge cells 24 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 12 and the sustain electrode 13 to generate a sustain discharge in the discharge cell 24 in which the address discharge has occurred and to cause the phosphor layer 23 of the corresponding discharge cell 24 to emit light. The image is displayed.

  Next, the hydrogen storage material 20 and the oxygen storage material 21 made of a platinum group element 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.

  By the discharge of the PDP 10, the present inventors decompose impure gases such as water molecules and hydrocarbon molecules released from the protective layer 16, the partition wall 22, the phosphor layer 23, etc. into hydrogen atoms, oxygen atoms, and carbon atoms. I noticed that. Then, focusing on the fact that the platinum group element is a hydrogen storage material that absorbs a large amount of hydrogen, the inventors have found that water and hydrocarbons can be removed by occluding hydrogen atoms in the platinum group element.

  First, the following experiment was conducted using platinum group elements. The hydrogen storage material 20 made of a platinum group element such as platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), osmium (Os), palladium (Pd), etc. is pulverized and each of these is used as an organic binder. A PDP 10 that was kneaded and dispersedly coated on the surface of the phosphor layer 23 as shown in FIG. 2 using a spray method or the like was produced. As a comparative example, a PDP was manufactured in the same manner using a hydrogen storage material 20 made of a polycrystalline platinum group element instead of a single crystal platinum group element.

  An image was displayed using the PDP 10 thus produced, and the presence or absence of “bleeding” and “burn-in” on the display surface was visually confirmed for about 1000 hours. As a result, all the PDPs 10 were confirmed to have certain effects such as the image quality deterioration caused by “smudge” and “burn-in” less than that of the conventional PDP 10, and particularly that the reduction effect was great with palladium.

  However, these platinum group elements are partially oxidized by a sealing process heated in an air atmosphere at 400 ° C. to 500 ° C. As a result, it was confirmed that the hydrogen storage ability of the original platinum group element could not be fully exhibited, and impure gases such as water and hydrocarbons could not be sufficiently removed.

  Therefore, as shown in FIG. 2, in Embodiment 1, zirconium (Zr), iron (Fe), vanadium (V), aluminum (Al), titanium (Ti) together with the hydrogen storage material 20 made of a platinum group element. An oxygen storage material 21 such as is dispersed on the surface of the phosphor layer 23 to prevent oxidation of the platinum group element. That is, in the sealing step, the atmosphere inside the PDP 10 is brought into a reduced state. In order to disperse and dispose the hydrogen storage material 20 and the oxygen storage material 21 on the surface of the phosphor layer 23, these powders are kneaded with an organic binder and dispersed on the surface of the phosphor layer 23 using a spray method or the like. Apply. At this time, it is desirable that the coverage of the hydrogen storage material 20 and the oxygen storage material 21 be 50% or less with respect to the phosphor layer 23 so as not to disturb the light emission of the phosphor.

  When such a PDP 10 is heated to 400 ° C. to 500 ° C. and sealed, the oxygen storage material 21 is activated to store oxygen, and the atmosphere in the PDP 10 becomes a reduced state with little oxygen, so that the hydrogen storage property is reduced. Material 20 is hardly oxidized. Since the hydrogen storage material 20 is not oxidized, the hydrogen storage capacity is very high, and image quality deterioration due to “bleeding” or “burn-in” of the PDP 10 is remarkably reduced. Further, in these PDPs, when palladium is used for the hydrogen storage material 20, the effect is particularly great, and image quality deterioration such as “smudge” and “burn-in” and a decrease in light emission luminance of the phosphor hardly occur. As described above, when the oxygen storage material 21 is arranged together with the hydrogen storage material 20 on the surface or inside of the phosphor layer 23, the hydrogen storage material 20 sufficiently stores the hydrogen decomposed by the discharge. Therefore, water molecules and hydrocarbon molecules are greatly reduced. As a result, the discharge characteristics can be stabilized and the change with time can be suppressed, and in addition, a decrease in luminance of the phosphor can be suppressed.

  In addition, the oxygen storage material 21 is not only a single element such as zirconium, iron, vanadium, aluminum, titanium, but also an alloy powder of two or more of which the surface is nitrided or oxidized. May be. According to such a configuration, the oxygen storage material can be easily handled at room temperature.

  In addition, the oxygen storage material 21 has a characteristic that the oxygen storage capacity decreases when heated many times. However, when the oxygen storage material 21 is disposed on the surface of the phosphor layer 23 as shown in the first embodiment, it is heated in the manufacturing process of the PDP 10. Since the opportunity to be processed can be minimized, the oxygen storage capacity is not lowered.

(Embodiment 2)
FIG. 4 is a cross-sectional view of PDP 10 in the second embodiment. In FIG. 4, the same components as those in FIG. The second embodiment is different from the first embodiment in the arrangement position of the hydrogen storage material 20 and the oxygen storage material 21. In the second embodiment, the hydrogen storage material 20 and the oxygen storage material 21 are combined. Dispersed on the surface of the protective layer 16.

  The particle sizes of the hydrogen storage material 20 and the oxygen storage material 21 must be such that no large gap is formed between the partition wall 22 and the protective layer 16, and is preferably 0.1 μm to 5 μm. In addition, the covering ratio of the hydrogen storage material 20 and the oxygen storage material 21 covering the protective layer 16 is 50% or less so that the hydrogen storage material 20 and the oxygen storage material 21 do not hinder the transmission of visible light. It is desirable. As in the first embodiment, the method for applying the hydrogen storage material 20 and the oxygen storage material 21 to the surface of the protective layer 16 uses a printing method, a spray method, a photolithography method, a dispenser method, an ink jet method, or the like.

  As a result of evaluating such a PDP 10 by the same method as in the first embodiment, the hydrogen storage material 20 sufficiently stores hydrogen decomposed as a result of discharge, thereby greatly reducing water molecules and hydrocarbon molecules. I was able to. As a result, it was possible to stabilize the discharge characteristics and suppress a change with time, and in addition, it was possible to suppress a decrease in luminance of the phosphor. From the above, when the oxygen storage material 21 is disposed on the surface of the protective layer 16 together with the hydrogen storage material 20, water molecules and hydrocarbon molecules can be greatly reduced, discharge characteristics are stabilized, and changes with time are suppressed. be able to.

  Further, the oxygen storage capacity of the oxygen storage material 21 decreases when it is heated many times. However, when the oxygen storage material 21 is disposed on the surface of the protective layer 16, the chance of being heated in the manufacturing process of the PDP 10 can be minimized, so that the oxygen storage capacity is not lowered.

  In the first embodiment and the second embodiment, the hydrogen storage material 20 and the oxygen storage material 21 are arranged on the same member of the PDP 10. However, they are arranged separately on the front substrate 11 and the back substrate 17. May be. In that case, the hydrogen storage material 20 can be mixed with the material of the partition wall 22 and the phosphor layer 23 and arranged. Moreover, the arrangement | positioning member of the hydrogen storage material 20 and the oxygen storage material 21 is not restricted to said example.

  As described above, according to the PDP of the present invention, the oxygen storage material disposed inside the PDP can keep the inside of the PDP in a reducing atmosphere and prevent oxidation of the hydrogen storage material. Therefore, it is possible to realize a highly reliable PDP in which the hydrogen storage capacity of the hydrogen storage material is increased, impurities such as water and hydrocarbons are sufficiently removed, and deterioration of the protective layer and the phosphor is suppressed.

  According to the PDP of the present invention, impurities such as water and hydrocarbons can be sufficiently removed, and deterioration of the protective layer and the phosphor can be suppressed, so that it is useful as a highly reliable PDP.

10 PDP
DESCRIPTION OF SYMBOLS 11 Front substrate 12 Scan electrode 12a, 13a Transparent electrode 12b, 13b Bus electrode 13 Sustain electrode 14 Display electrode pair 15 Dielectric layer 16 Protective layer 17 Back substrate 18 Data electrode 19 Base dielectric layer 20 Hydrogen storage material 21 Oxygen storage property Material 22 Bulkhead 23 Phosphor layer 24 Discharge cell

Claims (5)

A front substrate on which a plurality of display electrode pairs parallel to each other, a dielectric layer, and a protective layer are formed; a back substrate on which a plurality of data electrodes, a base dielectric layer, barrier ribs, and a phosphor layer are formed in parallel to each other; A plasma display panel in which the front substrate and the back substrate are arranged to face each other so that the display electrode pair and the data electrode intersect with each other and sealed around the plasma display panel, A plasma display panel comprising a hydrogen storage material made of a group element and an oxygen storage material containing at least one of zirconium, iron, vanadium, aluminum, and titanium. The plasma display panel according to claim 1, wherein the hydrogen storage material is palladium. The plasma display panel according to claim 1, wherein the oxygen storage material is an alloy powder of at least two of zirconium, iron, vanadium, aluminum, and titanium, the surface of which is nitrided or oxidized. The plasma display panel according to claim 1, wherein the oxygen storage material is disposed on a surface of the phosphor layer. The plasma display panel according to claim 1, wherein the oxygen storage material is disposed on a surface of the protective layer.

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