JP2010102840A - Plasma display panel - Google Patents

Abstract

A plasma display panel is provided in which impurities such as water and hydrocarbons are sufficiently removed to prevent deterioration of a protective layer and a phosphor.
A front substrate in which a plurality of rows of display electrodes including scan electrodes and sustain electrodes are formed and a dielectric layer is formed so as to cover the display electrodes and a protective layer is formed on the dielectric layer. A back substrate 31 which is disposed opposite to the front substrate 21 so as to form a discharge space, and which has a plurality of data electrodes formed in a direction intersecting with the display electrodes to form discharge cells at the intersection, and the back substrate 31 is provided with a partition wall 34 formed so as to partition the discharge space and having red, green and blue phosphor layers 35r, 35g, and 35b disposed therebetween, and the phosphor layer is made of a platinum group powder. The body 37 was arranged, and the amount of the powder 37 was varied for each emission color.
[Selection] Figure 2

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 on which a film is formed, and a rear substrate that is disposed to face the front substrate so as to form a discharge space and that has a plurality of data electrodes formed in a direction intersecting with the display electrodes to form discharge cells at the intersections. And a barrier rib formed on the rear substrate so as to partition the discharge space and having phosphor layers emitting red, green and blue light in between, and the phosphor layer is made of a platinum group powder. And the amount of the powder is different for each emission color.

  Further, the present invention is characterized in that platinum group powder is supported on the phosphor particles of the phosphor layer.

  According to the present invention, the counter discharge voltage in each color light emitting cell can be made uniform, and impure gases such as water and hydrocarbons can be efficiently and sufficiently absorbed and absorbed. Thus, it is possible to provide a PDP that is removed to prevent deterioration of the protective layer and the phosphor.

  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. In FIG. 2, the electrodes are omitted.

  As shown in FIG. 1, the PDP 10 is composed of a front plate and a back plate arranged to face each other, and a large number of discharge cells are formed between the front plate and the back plate arranged to face each other.

The front plate is formed by arranging a plurality of rows of display electrodes 24 including a pair of scanning electrodes 22 and sustain electrodes 23 on a glass front substrate 21 in parallel. Scan electrode 22 and sustain electrode 23 are formed in a pattern that repeats in the arrangement of scan electrode 22 -sustain electrode 23 -sustain electrode 23 -scan electrode 22. A dielectric layer 25 and a protective layer 26 made of MgO are formed so as to cover the display electrodes 24. Scan electrode 22 and sustain electrode 23 are formed by forming bus electrodes 22b and 23b made of Ag on transparent electrodes 22a and 23a made of a conductive metal oxide such as ITO, SnO ₂ and ZnO, respectively.

  The back plate is formed on a glass back substrate 31 by forming a plurality of data electrodes 32 made of a conductive material composed mainly of mutually parallel Ag, and forming a dielectric layer 33 so as to cover the data electrodes 32. In addition, a grid-like partition wall 34 is formed thereon, and a red phosphor layer 35r, a green phosphor layer 35g, and a blue phosphor layer 35b are formed on the surface of the dielectric layer 33 and the side surfaces of the partition wall 34. It is comprised by doing.

  Then, the front plate and the back plate are arranged to face each other so that the scan electrode 22 and the sustain electrode 23 and the data electrode 32 are three-dimensionally crossed, and the outer periphery thereof is bonded by a sealing material (not shown) such as a frit. And sealed. A discharge gas containing, for example, xenon (Xe) or the like is sealed in the discharge space.

  Here, as shown in FIG. 2, the discharge space sandwiched between the front plate and the back plate is divided into a plurality of sections by the barrier ribs 34, and the scan electrodes 22, the sustain electrodes 23, and the data electrodes 32 intersect. A red light emitting cell 36r, a green light emitting cell 36g, and a blue light emitting cell 36b are formed in the portion to be formed. The red light emitting cell 36r, the green light emitting cell 36g, and the blue light emitting cell 36b are discharged 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 constituting the PDP will be described. The scanning electrode 22 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 22b containing a metal such as silver (Ag) is laminated on 22a to increase conductivity. 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 dielectric layer 33 may be made of the same material as that of the dielectric layer 25, 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 34 is formed using, for example, a low melting point glass material. The phosphor layer 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.

  FIG. 3 is an electrode array diagram of the PDP in the embodiment of the present invention. N scanning electrodes Y1, Y2, Y3... Yn long in the row direction and n sustaining electrodes X1, X2, X3... Xn are arranged, and m data electrodes A1. Am is arranged. A light emitting cell is formed at a portion where the pair of scanning electrode Y1 and sustain electrode X1 intersects with one data electrode A1, and m × n light emitting 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.

  In the present embodiment, as shown in FIG. 2, a powder 37 made of a platinum group is disposed on the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor layer 35b. The platinum group powder 37 is disposed in such a manner that it is the largest on the blue phosphor layer 35b and the smallest on the green phosphor layer 35g. FIG. 2 schematically shows a state in which a platinum group powder 37 is dispersed on the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor layer 35b applied on the back substrate 31. Is shown. In the present embodiment, a powder 37 made of a platinum group having a particle size of 0.1 μm to 20 μm is used. In addition, the coverage of the platinum group powder 37 covering the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor layer 35b is 50% or less so as not to hinder the emission of the phosphor.

  In FIG. 2, the platinum group powder 37 is the most disposed on the blue phosphor layer 35b and the least on the green phosphor layer 35g, but the combination of phosphor materials and the thickness of the phosphor layer are shown. By appropriately adjusting the amount of arrangement, the counter discharge voltage can be made uniform in the light emitting cells of each color. Further, as shown in FIG. 4, the same effect can be obtained by dispersing a powder 37 made of a platinum group in the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor layer 35b. Further, the same effect can be obtained even when platinum group powder 37 is supported on the phosphor particle surfaces of the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor layer 35b.

  The platinum group powder 37 includes platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), iridium (Ir), and osmium (which absorbs hydrogen and easily releases secondary electrons). One or more platinum group powders of Os) can be used, and palladium is particularly desirable among them.

  As a method of dispersing the platinum group powder 37 on the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor layer 35b, for example, a spray method can be used. Further, as a method of dispersing the powder 37 made of a platinum group in the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor layer 35b, the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor At the time of forming the layer 35b, a powder 37 made of a platinum group may be mixed in advance, and the platinum group powder may be formed on the surface of the phosphor particles of the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor layer 35b. The powder 37 may be supported.

  The particle size of the powder 37 made of the platinum group is desirably 0.1 μm to 20 μm, and the mixing ratio is desirably about 0.01% to 2% in terms of the weight ratio of the phosphor to the powder. Since the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor layer 35b have a low phosphor filling rate of 60% or less, the inside of the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor layer 35b Even if the platinum group powder 37 is dispersed, the effect of occlusion of hydrogen is maintained, and the platinum group is formed on the phosphor particle surfaces of the red phosphor layer 35r, the green phosphor layer 35g, and the blue phosphor layer 35b. Even if the element is supported, the effect of occluding hydrogen can be obtained.

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.

  Further, the particle size of the phosphor of the red phosphor layer 35r is, for example, 4.5 μm, the particle size of the phosphor of the green phosphor layer 35g is, for example, 3.0 μm, and the phosphor particles of the blue phosphor layer 35b. For example, the diameter is 3.0 μm.

  Next, the action of the platinum group powder 37 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. And focusing on the fact that platinum group powder has the property of occluding a large amount of hydrogen, it is not possible to remove water and hydrocarbons as a result of occluding platinum atoms with small radius hydrogen atoms. I thought.

  In addition, the present inventors think that the discharge voltage of the PDP can be lowered as a result by disposing a platinum group powder in the discharge cell as a secondary electron emission source. It was.

  Therefore, the powder of platinum group (platinum, palladium, ruthenium, rhodium, iridium, osmium) is applied to the red phosphor layer, green fluorescence using the printing method, spray method, photolithography method, dispenser method, ink jet method, etc. A PDP coated on the body layer and the blue phosphor layer so as to adhere most on the blue phosphor layer and least on the green phosphor layer was produced. The powder made of the platinum group was kneaded with an organic binder as necessary, and applied as a paste.

  Also, platinum group powder is mixed with red phosphor particles, green phosphor particles and blue phosphor particles, and light is emitted using printing method, spray method, photolithography method, dispenser method, ink jet method, etc. A PDP was produced in which the cell was coated such that the platinum group powder was the most inside the blue phosphor layer and the least inside the green phosphor layer.

  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 addition, it was confirmed that the respective electrodes were opposed to each other with a uniform voltage without being displayed at a portion where the display should be performed or being displayed at an unnecessary portion. In particular, when a 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 was hardly lowered. This is because water molecules and hydrocarbon molecules are decomposed into hydrogen atoms, oxygen atoms and carbon atoms, and the powder of platinum group, especially palladium, occludes a large amount of hydrogen, so oxygen and carbon remain, This is because water molecules and hydrocarbon molecules were greatly reduced, and at the same time, the counter discharge voltage of each color became uniform because the platinum group powder released secondary electrons and lowered the discharge voltage. it is conceivable that.

  As is clear from this experiment, when the powder made of white metal is used as the secondary electron emission material, the discharge voltage of the discharge cell is lowered, so that the discharge characteristics of each color can be made uniform according to the amount to be arranged. it can. In addition, when powder made of white metal, especially palladium, is used as a hydrogen storage material, it absorbs hydrogen decomposed by the discharge, so water and hydrocarbon molecules can be greatly reduced, and the discharge characteristics. Can be stabilized, a change with time can be suppressed, and in addition, a decrease in luminance of the phosphor can be suppressed.

  As described in the above embodiments, by disposing different amounts of platinum group powder within the PDP light emitting cell, the discharge voltage of each color can be made uniform, and water molecules Instead of adsorbing impure gas with a large molecular diameter such as hydrogen and hydrocarbon molecules as they are, a powder made of platinum group such as palladium that absorbs a large amount of hydrogen decomposed by discharge is put inside the light emitting cell of PDP. By disposing, water and hydrocarbons can be greatly reduced. As a result, discharge characteristics can be stabilized, changes with time can be suppressed, and in addition, a decrease in luminance of the phosphor 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 Sectional drawing which shows the structure of the discharge cell part of PDP in other embodiment of this invention

Explanation of symbols

10 PDP
DESCRIPTION OF SYMBOLS 21 Front substrate 22 Scan electrode 23 Sustain electrode 24 Display electrode 25 Dielectric layer 26 Protective layer 31 Back substrate 32 Data electrode 33 Dielectric layer 34 Partition 35 Phosphor layer 36 Discharge cell 37 Platinum group powder

Claims (2)

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 A back substrate which is arranged to face each other so as to form a discharge space and which has a plurality of data electrodes formed in a direction intersecting with the display electrodes to form discharge cells at the intersection, and the discharge space is partitioned on the back substrate. And a partition wall on which a phosphor layer emitting red, green and blue light is disposed, and a platinum group powder is disposed on the phosphor layer, and the amount of the powder is A plasma display panel characterized by different colors for each emission color. The plasma display panel according to claim 1, wherein platinum group powder is supported on the phosphor particles of the phosphor layer.

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