JP2004071379A - Plasma display member, plasma display, and manufacturing method of plasma display member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma display member in which the change in a panel light emitting characteristics due to a long-time lighting of a panel is little, and provide plasma display and their manufacturing method. <P>SOLUTION: Fluorescent material layers are formed in the plasma display member, and a low refractive index layer having a refractive index lower than that of the fluorescent material is formed on the fluorescent material layer. The manufacturing method of this plasma display member is characterized by forming a low refractive index layer having a refractive index lower than that of the fluorescent material after forming the fluorescent material layers. <P>COPYRIGHT: (C)2004,JPO

Description

【００７９】
実施例１〜１４は、比較例１に比べて維持率が良好であり、特に実施例３〜５、９〜１２、および１４は初期発光特性においても同等以上であった。特に、実施例３、４、１４は初期発光特性にも優れ、維持率も高く高信頼性・長寿命なディスプレイであった。実施例６〜８、１３は初期発光特性が比較例１よりも劣るが、維持率が良好であった。比較例２は維持率はよいものの、紫外線がＴｉＯ_２により吸収されたり、蛍光体に入射する紫外線量が減ったため、初期発光特性が低すぎるものであった。
【００８０】
【発明の効果】
本発明によれば、蛍光体層の上に蛍光体層よりも屈折率の低い低屈折率層が形成されているので、長時間点灯による発光強度の低下を抑制でき、高信頼かつ長寿命なプラズマディスプレイ部材ならびにプラズマディスプレイを提供できる。
【図面の簡単な説明】
【図１】プラズマディスプレイの分解斜視図である。
【符号の説明】
１：前面板
２：ガラス基板
３：スキャン電極
４：サスティン電極
５：バス電極
６：透明誘電体層
７：ＭｇＯ保護膜
８：背面板
９：ガラス基板
１０：アドレス電極
１１：誘電体層
１２：隔壁層
１３：赤色蛍光体層
１４：緑色蛍光体層
１５：青色蛍光体層
１６：低屈折率層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plasma display (hereinafter abbreviated as PDP) having a phosphor layer, and a plasma display member.
[0002]
[Prior art]
PDPs have attracted attention as displays that can be used for thin and large televisions. FIG. 1 shows an exploded perspective view of a structural example of a PDP. The PDP is provided with a phosphor layer. The phosphor layer is made of a phosphor powder excited and emitted by ultraviolet rays, and a paste made of the phosphor powder and a resin component or a sheet-like paste is arranged on a panel substrate. Thereafter, the paste is fired at about 500 ° C. to form the paste through a process of burning off the resin component in the paste. Examples of the phosphor layer forming method include a screen printing method, a method of discharging a paste from a nozzle hole, and a photosensitive paste method.
[0003]
Further, in order to make PDP higher in display quality, it is desired to improve the emission intensity and emission efficiency of the phosphor layer. In particular, when the panel is turned on for a long time after being made into a panel, the emission intensity is likely to be reduced and color shift is likely to occur. In particular, in the case of a blue phosphor using an aluminate phosphor activated with divalent europium, the emission intensity and chromaticity shift are large, and the panel emission luminance and the white color temperature are reduced, which is problematic. . Also, W.S. Lehmann: J.M. Electrochem. Soc. , 130 (2), 426 (1983). According to the report, Zn often used for green phosphors ₂ SiO ₄ : Mn shows that it is weak to the impact of charged particles such as electrons and ions, and the light emission characteristics are easily changed.
[0004]
On the other hand, as an improvement of the phosphor powder itself, a technique for suppressing a decrease in emission intensity due to firing or long-time discharge by adjusting the amount of activation of divalent europium with respect to barium to be replaced in the aluminate phosphor. Are also disclosed. Japanese Patent Application Laid-Open No. H8-60147 discloses that the substitution amount of Ba having a larger ionic radius than that of divalent europium is reduced, that is, the activation amount of divalent europium is increased, and the time of discharge by long-time lighting discharge is increased. It is disclosed that the change is suppressed.
[0005]
Japanese Patent Application Laid-Open No. 7-320645 discloses that a thin film of a light-transmitting substance having a lower refractive index than each of the fluorescent substances is provided with a desired uniform thickness in order to protect the fluorescent substance from ions during discharge emission. The technique of coating with is disclosed.
[0006]
However, even with these means, the effect of suppressing a decrease in light emission intensity during long-time lighting after panelization has not been sufficient. In addition, the technique of coating a powder with a constant thickness has a problem that it is difficult to control the thickness and particles are likely to aggregate through the coating material.
[0007]
[Problems to be solved by the invention]
Therefore, the present invention has been made in view of the above-mentioned problems in the conventional technology, and an object of the present invention is to suppress a decrease in emission intensity in a long-time lighting after paneling, thereby achieving high reliability and long life. It is to provide a plasma display with a long life.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configurations. That is, a plasma display member having a partition and a phosphor layer formed on a substrate, wherein a low refractive index layer having a lower refractive index than the phosphor is formed on the phosphor layer. It is a display member. The low refractive index layer is made of silica, LiF, MgF ₂ , CaF ₂ , BaF ₂ , CeF ₄ , ThF ₄ , SrF ₂ , AlF ₃ ・ 3NaF, LiSrAlF ₆ , LiCaAlF ₆ A plasma display member comprising at least one member selected from the group consisting of:
[0009]
A plasma display comprising a partition and a phosphor layer formed on a substrate, wherein a low refractive index layer having a lower refractive index than the phosphor is formed on the phosphor layer. It is.
[0010]
Also, a method of manufacturing a plasma display member in which a partition and a phosphor layer are formed on a substrate, wherein a low refractive index layer having a lower refractive index than the phosphor is formed after the phosphor layer is formed. The manufacturing method of the plasma display member described above.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
[0012]
The plasma display member of the present invention is a plasma display member having a phosphor layer formed thereon, and it is essential that a low refractive index layer having a lower refractive index than the phosphor is formed on the phosphor layer. By forming a low-refractive-index layer having a lower refractive index than the phosphor on the phosphor layer, the phosphor surface is not directly exposed to plasma, so that the luminance of the phosphor is not deteriorated due to long-time operation of the panel. This is because it is suppressed.
[0013]
Further, since the refractive index is lower than that of the phosphor, the ratio of the excited ultraviolet rays reflected on the phosphor layer surface is reduced, and the excited ultraviolet rays can be effectively used for light emission. Generally, a material having a low refractive index absorbs a small amount of ultraviolet light and can use ultraviolet light more effectively.
[0014]
The low refractive index layer is preferably formed on the phosphor layers of all colors, but there may be a phosphor layer on which the low refractive index layer is not formed. Further, the low refractive index layer may be formed partially (for example, only in the discharge cell portion) in the phosphor layer.
[0015]
The refractive index of the phosphor used in the PDP is usually 1.53 or more. In this case, it means that the refractive index of the low refractive index layer is smaller than 1.53. To be precise, it is necessary to compare the refractive index values at the ultraviolet wavelength (147 nm) used for the PDP, but such accurate refractive index values at vacuum ultraviolet light are not often measured. Therefore, in the present invention, the refractive index is set at a wavelength around 500 nm. The difference in refractive index between the phosphor and the low refractive index layer is preferably 0.04 to 0.4. More preferably, it is 0.06 to 0.2. If the difference in refractive index is smaller than 0.04, the refractive index becomes substantially equal to that of the phosphor, so that the effect of preventing reflection tends to be hardly exhibited. When the refractive index difference is larger than 0.4, that is, when the refractive index is smaller than 0.4 with respect to the phosphor, the refractive index difference is too large and the scattering at the interface tends to increase.
[0016]
Those having a refractive index lower than 1.53 include silica and fluoride. Specifically, silica, LiF, MgF ₂ , CaF ₂ , BaF ₂ , CeF ₄ , ThF ₄ , SrF ₂ , AlF ₃ ・ 3NaF, LiSrAlF ₆ , LiCaAlF ₆ It is preferable to include at least one or more selected from the group of In terms of raw material costs, silica, MgF ₂ , CaF ₂ , BaF ₂ Is preferred. In a layer having a higher refractive index than the fluorescent material, the reflected ultraviolet light increases and the ultraviolet light incident on the fluorescent material decreases, so that the luminance decreases. Further, in general, high refractive index materials such as titanium oxide, silicon, silicon carbide, and zircon absorb ultraviolet rays, so that the problem that the ultraviolet rays incident on the phosphor is further reduced occurs. .
[0017]
To achieve the same effect, use MgF ₂ It is also conceivable to use a phosphor coated with a material having a low refractive index such as a wet or dry type by a wet method or a dry method. It is simpler and superior.
[0018]
The low refractive index layer in the invention is preferably in the form of a film from the viewpoint of preventing reflection of ultraviolet rays and protection from plasma. Here, the term "film-like" refers to a structure in which low-refractive-index materials are continuously connected, rather than being scattered in an island-like manner, and includes a case where the materials are connected in a network.
[0019]
The thickness of the low refractive index layer is preferably from 10 nm to 5 μm. If the thickness is less than 10 nm, the function of protecting the phosphor from plasma is not sufficiently developed. If the thickness is more than 5 μm, the discharge space is narrowed and the discharge efficiency is reduced, and the amount of ultraviolet absorption in the low refractive index layer is increased and the luminance is apt to be reduced. Generally, a material having a low refractive index absorbs a small amount of ultraviolet light, and therefore, it is preferable that the material having the same thickness has a small refractive index. More preferably, it is 10 nm to 1 μm. More preferably, it is 10 to 200 nm. Considering normal incidence, the optimum thickness and refractive index of the low-refractive-index layer can be calculated from the ultraviolet wavelength (147 nm) and the refractive index of the phosphor, but there is no clear correlation between the calculated value and the luminance. This is because it is not easy to form a low-refractive-index layer with a uniform thickness on a phosphor layer consisting of phosphor particles of several μm in fact, not only at normal incidence but also at various angles and multiple incidences. Probably because there is no.
[0020]
When the low refractive index layer is formed in a film shape, a vacuum process is often used as described later. Usually, it is easy to grow into an island shape at the beginning of film formation in a vacuum process, but by increasing the film thickness to 10 nm or more by elongating the film formation time, the film is formed in the region between the islands as well. Cheap.
[0021]
In the present invention, the low refractive index layer can be formed using low refractive index fine particles having a refractive index of less than 1.5. There is an advantage that the manufacturing cost can be reduced as compared with the case where a vacuum process is used. Since the present invention aims to prevent the reflection of ultraviolet rays and protect the plasma from plasma, it is more effective for the low refractive index fine particles to have as small an average particle diameter as possible, that is, to have a short distance to the phosphor surface. This is because even if the low refractive index fine particles are added at the same ratio, the smaller the average particle diameter, the higher the coverage of the phosphor surface. The average particle diameter of the low refractive index fine particles is preferably from 1 to 3000 nm. It is more preferably 1 to 800 nm, further preferably 1 to 200 nm, and still more preferably 1 to 30 nm.
[0022]
The silica fine particles are not particularly limited. For example, “Aerosil” (for example, Aerosil 50, 380, R974, etc.) manufactured by Nippon Aerosil Co., Ltd., “Snowtex” manufactured by Nissan Chemical Co., Ltd., ( "Adma Fine" manufactured by Admatechs Co., Ltd. can be preferably used.
[0023]
Fluoride fine particles are formed, for example, by reacting calcium carbonate and hydrofluoric acid to form CaF ₂ For example, by reacting an oxide or carbonate with hydrofluoric acid. For example, “fluorine compound for optical glass” manufactured by Morita Chemical Co., Ltd. can be used. If necessary, dry / wet pulverization and classification can be performed to adjust the particle size distribution. When the fluoride is water-soluble, it can be prepared by a spray drying method.
[0024]
Next, the structure and manufacturing procedure of the plasma display member and the plasma display of the present invention will be described with reference to FIG. Here, the basic structure and the like of an AC type plasma display which is the most common as a plasma display will be described as an example, but the present invention is not necessarily limited to this structure.
[0025]
In the plasma display, phosphor layers 13 to 15 (in FIG. 1, only the back plate 8 has a phosphor layer formed thereon) formed on the front plate and / or the back plate face the internal space. As described above, a member in which the front plate 1 and the back plate 8 are sealed is such that a discharge gas is sealed in the internal space. That is, the front plate 1 is a substrate on the display surface side, on which transparent electrodes (sustain electrodes 4 and scan electrodes 3) for display discharge are formed. In the case of an AC type plasma display, an MgO protective film 7 is often formed as a protective film for the electrodes and the transparent dielectric layer 6. An electrode (address electrode 10) for selecting an address of a cell to be displayed is formed on the back plate 8. The partition layer 12 and the phosphor layers 13 to 15 for partitioning the cells may be formed on one or both of the front plate 1 and the back plate 8, but are formed only on the back plate 8 as shown in FIG. There are many. In the plasma display, the front plate 1 and the back plate 8 are sealed, and a discharge gas such as Xe-Ne or Xe-Ne-He is sealed in an internal space between the two.
[0026]
Next, a method of manufacturing the back plate will be described.
[0027]
As the substrate used for the back plate as the PDP member of the present invention, "PD200" manufactured by Asahi Glass Co., Ltd. or "PP8" manufactured by Nippon Electric Glass Co., Ltd. which is heat-resistant glass for PDP can be used in addition to soda glass. .
[0028]
Address electrodes are formed on a glass substrate in stripes at a pitch of the discharge cells using a metal such as silver, aluminum, chromium, or nickel. As a method of forming, a method of pattern-printing a metal paste containing these metal powders and an organic binder as main components by screen printing, or applying a photosensitive metal paste using a photosensitive organic component as an organic binder, A photosensitive paste method can be used in which pattern exposure is performed using a photomask, unnecessary portions are dissolved and removed in a development step, and the electrode pattern is formed by heating and baking usually at 400 to 600 ° C. In addition, an etching method is used in which a metal such as chromium or aluminum is deposited on a glass substrate, a resist is applied, and the resist is subjected to pattern exposure and development using a photomask and then etched to remove unnecessary metal. Can be.
[0029]
Further, a dielectric layer may be provided on the address electrode layer for stabilizing discharge.
On the glass substrate on which the address electrode layer is formed, a partition located in parallel with the electrode layer is formed by a sandblast method, a mold transfer method, a photolithography method, or the like. The material of the partition used in the present invention is not particularly limited, and a glass material containing an oxide of silicon and boron is applied. In addition, it is advantageous to form a glass material having a refractive index of 1.5 to 1.68 by 70% by weight or more when formed by photolithography. The partition shape is not particularly limited, but a stripe shape, a cross-girder shape, a hexagonal shape, or the like is preferable.
[0030]
A phosphor layer is formed using a phosphor paste on the glass substrate on which the electrode layer and the partition layer have been formed. It can be formed by a photolithography method using a photosensitive phosphor paste, a dispenser method, a screen printing method, or the like. Although the thickness of the phosphor layer is not particularly limited, it is 10 to 30 μm, more preferably 15 to 25 μm in a three-electrode surface discharge type reflection plasma display. The baking for removing the resin component is preferably performed at a temperature at which the resin to be used is sufficiently debindered. In the case where a cellulose resin is used as the resin, the temperature is 470 to 550 ° C. When an acrylic resin is used, the temperature is 430 to 490 ° C. If the firing temperature is too low, the resin component tends to remain, while if it is too high, distortion is introduced into the glass substrate or the phosphor powder deteriorates.
[0031]
The phosphor powder is not particularly limited, but the following phosphors are preferred from the viewpoints of emission intensity, chromaticity, color balance, life, and the like. Blue is activated divalent europium, aluminate phosphor and CaMgSi ₂ O ₆ It is.
[0032]
In the case of using an aluminate phosphor, it is preferable that the composition is such that the aluminum element is excessive with respect to the stoichiometric composition in order to further suppress deterioration during paste baking. The excess amount of the aluminum element is preferably 10% or less based on the stoichiometric composition. If the excess amount is more than 10%, a single phase will not be formed during the synthesis of the phosphor powder, and a by-product will be generated, the emission intensity will decrease, and the y value of the chromaticity will increase. Tends to have a narrower color reproducibility range. Preferably, it is in the range of 0.1 to 9.5% based on the stoichiometric composition. More preferably, it is in the range of 1 to 9%, and further preferably, it is in the range of 2 to 8%.
[0033]
Here, as the aluminate having a stoichiometric composition, for example, MMgAl ₁₄ O ₂₃ , MMgAl ₁₀ O ₁₇ , MMg ₂ Al ₁₆ O ₂₇ , MMg ₂ Al ₁₄ O ₂₄ , M ₂ Mg ₂ Al ₁₂ O ₂₂ , M ₃ Mg ₄ A _l8 O ₁₈ , M ₃ Mg ₅ Al ₁₈ O ₂₅ And the like. The element M preferably contains at least one of Ba, Sr and Ca. Above all, MMgAl ₁₀ O ₁₇ The aluminate of the atomic formula is more preferably used.
[0034]
Also, MMgAl ₁₀ O ₁₇ In the case of the aluminate phosphor of the atomic formula, the amount of magnesium element is preferably 90 to 100% with respect to the stoichiometric composition in order to suppress a decrease in luminance and a shift in chromaticity due to paste firing. This is because when the magnesium element amount is less than 90% or more than 100% with respect to the stoichiometric composition, a decrease in luminance and a shift in chromaticity after paste firing tend to increase.
[0035]
Further, the substitution amount of divalent europium in the aluminate phosphor is preferably in the range of 5 to 20 at% with respect to the element M. If the substitution amount is less than 5 at%, an electron trap having a deep energy level near divalent europium is formed by prolonged lighting after paneling, and the emission intensity may decrease and the chromaticity shift may increase. . If the substitution amount is more than 20 at%, the emission intensity may be reduced and the chromaticity deviation may be increased by baking the paste, and if it is more than 50 at%, the emission intensity may be reduced to unfired phosphor powder due to concentration quenching. .
[0036]
In the case of green, Zn is considered in terms of panel brightness ₂ SiO ₄ : Mn, YBO ₃ : Tb, BaMg ₂ Al ₁₄ O ₂₄ : Eu, Mn, BaAl ₁₂ O ₁₉ : Mn, BaMgAl ₁₄ O ₂₃ : Mn is preferred. More preferably, Zn ₂ SiO ₄ : Mn.
[0037]
In red, the (Y, Gd) BO ₃ : Eu, Y ₂ O ₃ : Eu, YPVO: Eu, YVO ₄ : Eu is preferred. More preferably, (Y, Gd) BO ₃ : Eu.
[0038]
The phosphor paste may contain a phosphor other than the phosphor powder and other inorganic particles, but the content of the phosphor powder is preferably 70% by weight or more. It is more preferably at least 85% by weight. More preferably, it is 95% by weight or more. Specifically, 3Ca ₃ (PO ₄ ) ₂ ・ Ca (F, Cl) ₂ : Sb, Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, (Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, (Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ ・ NB ₂ O ₃ : Eu, (Ba, Ca, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, Sr ₂ PO ₇ : Sn, Ba ₂ P ₂ O ₇ : Ti, Ca ₃ (PO ₄ ) ₂ : Tl, (Ca, Zn) ₃ (PO ₄ ) ₂ : Tl, Sr ₂ P ₂ O ₇ : Eu, SrMgP ₂ O ₇ : Eu, Sr ₃ (PO ₄ ) ₂ : Eu, (Ba, Sr, Mg) ₃ Si ₂ O ₇ : Pb, (Ba, Mg, Zn) ₃ Si ₂ O ₇ : Pb, BaSi ₂ O ₅ : Pb, Ba ₃ MgSi ₂ O ₈ : Eu, Y ₂ SiO ₅ : Ce, CaWO ₄ : May contain a phosphor such as Pb. In addition to the phosphor, pigments such as carbon black and titanium black, and binders such as water glass and low melting point glass may be included.
[0039]
The particle diameter of the phosphor powder is such that the cumulative average particle diameter D50 measured by a laser diffraction scattering method (for example, wet measurement using an HRA particle size distribution analyzer manufactured by Microtrac) is in the range of 0.5 to 10 μm, and more preferably 1 to 10. It is preferably within a range of 5 μm. More preferably, it is 1-4 μm. By controlling the average particle size to 0.5 μm or more, the cohesiveness of the powder is suppressed, the paste coatability is improved, and the denseness and homogeneity of the coating film and the fired phosphor layer are improved. can do. When the thickness is 10 μm or less, unevenness on the surface of the phosphor layer after firing can be suppressed, and a decrease in luminance and a variation in luminance due to irregular reflection of light emission can be further prevented.
[0040]
The maximum particle size of the phosphor powder is preferably 40 μm or less, more preferably 20 μm or less. By setting the maximum particle size to 40 μm or less, unevenness of the phosphor layer after firing can be further suppressed. Further, the thickness is preferably 20 μm or less from the viewpoint of powder filling properties. Also, the maximum particle size is related to the method of applying the phosphor paste, and in the case of the screen printing method, it is related to the aperture ratio of the mesh, and is related to the nozzle inner diameter such as the dispenser method. Is the key.
[0041]
Next, the low refractive index layer of the present invention is formed. When the low refractive index layer is formed in a film shape, it can be formed by a vacuum evaporation method, a sputtering method, a plasma evaporation method, or the like. For uniform formation over a large area at low cost, a vacuum evaporation method and a sputtering method are more preferable. When the low refractive index layer is formed on the fired phosphor layer, care must be taken because the phosphor powder is liable to be scattered at the beginning of evacuation or at the time of transporting the substrate.
[0042]
When the low refractive index layer is formed of fine particles, the low refractive index layer can be coated on the phosphor layer using a coating liquid (slurry or sol) containing the low refractive index fine particles. For example, a low-refractive-index layer can be formed by forming a coating liquid containing low-refractive-index fine particles and a solvent by a spray atomizing method or a dipping method and drying the coating liquid. Further, it can be formed by a dispenser method or a screen printing method in which a coating liquid containing low refractive index fine particles, a resin, and a solvent is discharged from a minute nozzle.
[0043]
Examples of the coating liquid containing low refractive index fine particles and a solvent include silica, LiF, and MgF dispersed in ethanol, methanol, and isopropyl alcohol. ₂ , CaF ₂ , BaF ₂ , CeF ₄ , ThF ₄ , SrF ₂ , AlF ₃ ・ 3NaF, LiSrAlF ₆ , LiCaAlF ₆ Can be preferably used. The ratio between the low refractive index fine particles and the solvent is not particularly limited, but it is preferable that the low refractive index fine particles / solvent = 2/98 to 30/70 (weight ratio). More preferably, it is 5/95 to 25/75 (weight ratio).
[0044]
When a binder resin is used, a thermoplastic resin which is usually baked at a relatively low temperature of about 400 to 550 [deg.] C. with little deterioration of the emission intensity of the phosphor powder is preferable. , Propylcellulose, hydroxymethylcellulose, hydroxylethylcellulose, hydroxylpropylcellulose, cellulose-based resins such as hydroxylethylpropylcellulose, and polymethyl methacrylate, poly-i-propyl methacrylate, poly-i-butyl methacrylate and, if necessary, their coating properties. (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) Acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, hydroxylethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxylbutyl (meth) acrylate, phenoxy-2-hydroxy An acrylic resin obtained by copolymerizing an acrylic monomer such as propyl (meth) acrylate or glycidyl (meth) acrylate can be used.
[0045]
The solvent used for the coating liquid is not particularly limited, but when a resin is used, any organic solvent that does not separate from the resin component may be used, and alcohols, ethers, esters, and the like and a mixture thereof are preferable. In particular, it is preferable to use terpineol (terpineol) because it dissolves the resin component well, sufficiently disperses the low refractive index fine particles, and has excellent coatability. Commercial terpineol is a mixture of three isomers and is a liquid with a boiling point of 217-219 ° C. In order to adjust the viscosity of the coating liquid, it is preferable to mix terpineol with an aromatic alcohol having a similar boiling point, for example, benzyl alcohol. The ratio between the resin component and the solvent can be appropriately adjusted from the viewpoint of the viscosity of the coating liquid, the coating property of the coating liquid, and the like.
[0046]
The content of the low-refractive-index fine particles and the resin component is preferably 70 to 95% by weight of the low-refractive fine particles and 5 to 30% by weight of the resin component based on the coating liquid in a dry state. More preferably, the content of the low refractive index fine particles is 80 to 90% by weight, and the content of the resin component is 10 to 20% by weight. Here, the resin component refers to a solid content before dissolving the resin in a solvent.
[0047]
If the amount of the resin component is too small, the dispersion stability of the low refractive index fine particles in the coating liquid, the viscosity and fluidity of the coating liquid, the retention of the thickness of the coating film, and the like tend not to be obtained. On the other hand, if the amount of the resin component is too large, the removal of the resin component by firing tends to be incomplete and tends to remain as a residue, and it takes time to remove the organic components by firing, and the firing of the phosphor powder itself is deteriorated. Tend to increase.
[0048]
The coating liquid may further contain an organic compound dispersant such as an anionic or nonionic surfactant, a higher aliphatic alcohol, a plasticizer (for example, dibutyl phthalate, dioctyl phthalate, polyethylene glycol, glycer, etc.), if necessary. ) May be contained. In addition, a thixotropic agent may be added as necessary from the viewpoint of stringing of the coating liquid and the coating shape. For example, silica fine particles (for example, “380” and “R974” manufactured by Nippon Aerosil Co., Ltd.).
[0049]
The coating liquid is not particularly limited, but the organic binder solution prepared by heating and dissolving the resin in a solvent using a stirrer (usually at about 80 ° C.) is used. It can be manufactured by kneading using a dispersing machine such as a ball mill or a bead mill. For example, in addition to mixing the organic binder and the low-refractive-index fine particles that have been adjusted to a predetermined amount in advance, the organic binder and the phosphor are mixed with a solvent or resin component smaller than the predetermined amount, and then the remaining solvent is mixed. Alternatively, a resin component can be added and mixed. Above all, the amount of the resin component is made smaller than the predetermined amount, the organic binder and the low refractive index fine particles are mixed, a slurry is prepared in advance, and finally the remaining resin component and the solvent are added and mixed to the predetermined amount. Is preferred.
[0050]
When a coating liquid containing a resin component is used, a baking step for removing the resin component after application is required. It can be fired at 430 to 550 ° C. in an atmosphere containing oxygen such as the air. When an acrylic resin is used as the resin, it is preferable to perform firing not only in the air but also in an atmosphere of an inert gas such as nitrogen. This is because deterioration of the phosphor due to firing is easily suppressed. When a coating liquid containing no resin component is used, it is preferable that the coating liquid is applied on the unfired phosphor layer from the viewpoint of the shape retention of the phosphor layer. Thereafter, the phosphor layer is fired. Further, when using a coating solution containing a resin component, for the purpose of reducing the number of firings, it may be applied on an unfired phosphor layer, and firing the phosphor layer and the low refractive index layer may be performed at once. Good.
In this way, the back plate can be manufactured.
[0051]
Next, a method of manufacturing the front plate will be described.
The glass substrate used for the front plate is the same as that described for the back plate.
A transparent electrode such as tin oxide or ITO is formed on a glass substrate by a lift-off method, a photoetching method, or the like.
[0052]
Next, a bus electrode layer is patterned on the glass substrate on which the transparent electrode is formed, by screen printing of silver, aluminum, copper, gold, nickel, or the like, or by a photolithography method using a photosensitive conductive paste.
[0053]
A transparent dielectric layer is formed on a glass substrate on which a transparent electrode and a bus electrode are formed by a screen printing method or the like. Although the transparent dielectric material used in the present invention is not particularly limited, PbO, B ₂ O ₃ , SiO ₂ A dielectric material such as a lead-based glass or a ZnO-based material is used.
[0054]
Further, for the purpose of protecting the transparent dielectric layer and lowering the discharge voltage, a protective film may be formed so as to cover the transparent dielectric layer. Generally, an oxide of an alkaline earth metal can be used for the protective film. Particularly, MgO is preferably used because it has excellent sputter resistance and a high secondary electron emission coefficient. The MgO protective film is formed by electron beam evaporation, reactive sputtering of a Mg target, or ion plating.
In this way, the front plate can be manufactured.
[0055]
Next, a method for manufacturing a plasma display will be described.
After sealing the back plate and the front plate using the back plate and the front plate of the plasma display member, a discharge gas composed of helium, neon, xenon, or the like is supplied to a space formed between the front and rear substrates. After encapsulation, a drive circuit is mounted and aging is performed to produce a plasma display.
[0056]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to this.
[0057]
(Measuring method)
(1) Light emission characteristics and maintenance rate of panel
The luminance and chromaticity of the panel were measured such that the entire panel was lit white under discharge conditions of a discharge sustaining voltage of 180 V, a frequency of 30 kHz, and a pulse width of 3 μm, and the luminance B and chromaticity y were measured using a Minolta CS-1000 spectral radiance meter. Then, B / y was calculated. B immediately after making the plasma display ₀ / Y ₀ (Initial light emission characteristic), and after continuous lighting for 200 hours, B ₂₀₀ / Y ₂₀₀ And the maintenance ratio was calculated by the following equation.
Retention rate (%) = 100 × (B ₂₀₀ / Y ₂₀₀ ) / (B ₀ / Y ₀ )
(2) Average thickness
As in the case of forming on the phosphor layer, a low-refractive index layer was formed on a glass substrate to which a polyimide tape was partially applied, and after peeling off the polyimide tape, the thickness at five locations was determined, and the average was determined. The value was taken as the average thickness.
[0058]
(Example 1)
First, a back plate was manufactured.
An address electrode having a width of 200 μm, a thickness of 3 μm, and a pitch of 360 μm was formed on a “PD200” 3-inch glass substrate using a photosensitive silver paste.
[0059]
Next, a dielectric layer was formed to a thickness of 10 μm by a screen printing method. The following composition was used for the dielectric paste. 80 parts by weight of glass powder A, 1 part by weight of filler (silicon oxide: Aerosil 200 manufactured by Nippon Aerosil Co., Ltd.), 7 parts by weight of titanium oxide, 20 parts by weight of ethylcellulose resin, 0.3 part by weight of dispersant (NOPCOSPARS 092 (manufactured by San Nopco)), leveling 1 part by weight of agent A composition of glass powder A is 38% of bismuth oxide, 6% of silicon oxide, 20% of boron oxide, 20% of zinc oxide, and 4% of aluminum oxide, and has a glass transition point of 475 ° C and a softening point of 515 ° C. , Thermal expansion coefficient 75 × 10 ^-7 / ° C, density 4.61 g / cm ³ It is.
The paste was prepared by kneading a mixture of these components with a three-roller kneader.
[0060]
Thereafter, a partition layer pattern was formed by a photolithography method using a photosensitive partition paste. The composition of the partition wall paste used was as follows. 60 parts by weight of glass powder B, 10 parts by weight of a binder (copolymer of methyl methacrylate and methacrylic acid (average molecular weight: 25,000, acid value: 102), 10 parts by weight of a photosensitive monomer (tetrapropylene glycol diacrylate), photopolymerization initiator ( Ciba Geigy, Irgacure 369), 17 parts by weight of γ-butyrolactone.
[0061]
Glass powder B has a glass transition point of 495 ° C., a softening point of 530 ° C., and a thermal expansion coefficient of 75 × 10 ^-7 / ° C, density 2.54g / cm ³ Was used.
The paste was prepared by kneading a mixture of these components with a three-roller kneader.
[0062]
The photosensitive paste coating film is dried and then dried through a striped pattern photomask to 50 mJ / cm. ² And then developed with a 0.2% aqueous solution of monoethanolamine to form a partition pattern. Thereafter, the resultant was fired at a firing temperature of 570 ° C. for 15 minutes to obtain a partition wall layer having a good shape.
[0063]
Next, a phosphor layer was formed in the following manner. The blue phosphor is Ba _0.9 MgAl ₁₀ O ₁₇ : Eu _0.1 And the red phosphor is (Y, Gd) BO ₃ : Eu, green phosphor Zn ₂ SiO ₄ : Mn was used. Terpineol: benzyl alcohol: ethyl cellulose (“Ethocel 20cP”) = prepared a resin component solution which was previously heated and dissolved at 80 ° C. in a ratio of 10:70:18, and a phosphor powder 80% by weight and a resin component (solid content) 18% %, And the phosphor powder and the resin component solution were kneaded with three rollers. This phosphor paste was applied onto the partition by a dispenser method using a nozzle having a discharge port with a hole diameter of 150 μm so that both the partition bottom and the side had a thickness of about 30 μm. After drying at 80 ° C. for 20 minutes, baking was performed in air at 500 ° C. for 15 minutes to remove the resin component in the phosphor paste.
[0064]
Next, a low-refractive-index layer was formed on the phosphor layer using a vacuum deposition method so that silica had an average thickness of 0.05 μm. The film was formed at a constant film formation rate of 10 nm / min without heating the substrate. In order to reduce the in-plane distribution of the film thickness as much as possible, the substrate was formed while revolving around its own axis.
Thus, a back plate was produced.
[0065]
Next, a front plate was produced.
Scan electrodes having a pitch of 1080 μm and a line width of 350 μm were formed on a 3-inch glass substrate “PD200” manufactured by Asahi Glass Co. using ITO. A bus electrode having an electrode width of 100 μm and a thickness of 3 μm was formed on the substrate by a photosensitive silver paste method.
[0066]
Next, a transparent dielectric glass paste was screen-printed to form a transparent dielectric with a thickness of 30 μm so as to cover the bus electrode in the display area.
[0067]
A front plate was prepared by forming a magnesium oxide layer having a thickness of 1.0 μm as a protective film by electron beam evaporation on the substrate on which the dielectric was formed.
[0068]
PbO, B are arranged so that the electrodes of the front plate and the rear plate are positioned vertically. ₂ O ₃ The front plate and the back plate were sealed using a glass frit made of a ceramic filler or the like. After sealing, the inside of the sealed front plate and back plate is evacuated while heating to about 350 ° C., cooled to room temperature, and then cooled to Xe5% -Ne bal. Gas was sealed up to 66.5 kPa. Finally, a drive circuit was mounted and aging was performed for 24 hours to complete a PDP.
[0069]
(Examples 2 to 5)
As shown in Table 1, a plasma display was manufactured in the same manner as in Example 1 except that the low refractive index material and the average thickness were changed.
[0070]
(Examples 6 to 9)
After the phosphor paste was applied and dried at 80 ° C. for 20 minutes, a coating liquid containing fine particles having a low refractive index was applied by a dispenser method without firing. The coating liquid was a silica particle: ethyl cellulose (solid content) = 4: 1 constant by weight ratio, and a coating liquid having a changed viscosity was prepared by adjusting the addition amount of benzyl alcohol. The coating liquid was kneaded using three rolls. The silica fine particles used had an average particle diameter of 12 nm. As the ethyl cellulose, “Ethocel 20cP” was used. The thickness of the low refractive index layer was controlled by changing the viscosity of the coating liquid, the discharge pressure, and the coating speed. The coating thickness and the composition of the blue phosphor used were as shown in Table 1. Except for these, a plasma display was manufactured in the same manner as in Example 1.
[0071]
(Example 10)
Before forming the low refractive index layer, the phosphor display layer was baked in the air at 500 ° C. for 15 minutes to remove the resin component in the phosphor paste in the same manner as in Example 9, except that the phosphor component was removed. Was prepared. The average thickness of the low refractive index layer was as shown in Table 1.
[0072]
(Example 11)
Example 9 except that a silica sol having an average particle diameter of 16 nm (solvent: γ-butyrolactone, concentration: 20% by weight) was used as a coating liquid containing low refractive index fine particles to form a low refractive index layer by a spray method. A plasma display was produced in the same manner as described above. The average thickness of the low refractive index layer was as shown in Table 1.
[0073]
(Examples 12 and 14)
A coating solution containing low refractive index fine particles is coated with MgF having an average particle size of 80 nm. ₂ A plasma display was produced in the same manner as in Example 6, except that a slurry (solvent: isopropyl alcohol, concentration: 15% by weight) was used to form a low refractive index layer by a spray atomization method. The average thickness of the low refractive index layer was as shown in Table 1.
[0074]
(Example 13)
To a coating solution containing low refractive index fine particles, add MgF having an average particle size of 2.8 μm. ₂ A plasma display was produced in the same manner as in Example 6, except that the fine particles were used. The average thickness of the low refractive index layer was as shown in Table 1.
[0075]
(Comparative Example 1)
A plasma display was manufactured in the same manner as in Example 1, except that the low refractive index layer was not formed.
[0076]
(Comparative Example 2)
A coating liquid containing low refractive index fine particles is coated with TiO having an average particle diameter of 0.2 μm. ₂ A plasma display was produced in the same manner as in Example 6, except that the fine particles were used. The average thickness of the low refractive index layer was as shown in Table 1.
[0077]
For Examples 1 to 14 and Comparative Examples 1 and 2, the material of the low refractive index layer, the refractive index at 500 nm, the configuration, the average particle diameter and average thickness of the fine particles, the chemical formula of the blue phosphor, the initial light emission characteristics, and the retention rate It is shown in Table 1.
[0078]
[Table 1]

[0079]
Examples 1 to 14 had better retention rates than Comparative Example 1, and Examples 3 to 5, 9 to 12, and 14 also had equal or better initial light emission characteristics. In particular, Examples 3, 4, and 14 were excellent in initial light emission characteristics, high in maintenance ratio, and high in reliability and long life. Examples 6 to 8 and 13 were inferior to Comparative Example 1 in initial light emission characteristics, but had good retention rates. In Comparative Example 2, although the maintenance ratio was good, the ultraviolet light was TiO. ₂ And the amount of ultraviolet rays incident on the phosphor was reduced, so that the initial light emission characteristics were too low.
[0080]
【The invention's effect】
According to the present invention, since the low refractive index layer having a lower refractive index than the phosphor layer is formed on the phosphor layer, it is possible to suppress a decrease in light emission intensity due to long-time lighting, and to achieve a high reliability and a long life. A plasma display member and a plasma display can be provided.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a plasma display.
[Explanation of symbols]
1: Front panel
2: Glass substrate
3: Scan electrode
4: Sustain electrode
5: Bus electrode
6: transparent dielectric layer
7: MgO protective film
8: back plate
9: Glass substrate
10: Address electrode
11: Dielectric layer
12: partition layer
13: Red phosphor layer
14: Green phosphor layer
15: Blue phosphor layer
16: low refractive index layer

Claims (8)

A plasma display member having a phosphor layer formed thereon, wherein a low refractive index layer having a lower refractive index than the phosphor is formed on the phosphor layer. Low refractive index layer, include _{silica, LiF, MgF 2, CaF 2} , BaF 2, CeF 4, ThF 4, SrF 2, AlF 3 · 3NaF, at least one or more selected from the group of LiSrAlF 6, LiCaAlF ₆ The plasma display member according to claim 1, wherein: 3. The plasma display member according to claim 1, wherein the low refractive index layer is made of fine particles. 3. The plasma display member according to claim 1, wherein the low refractive index layer is in the form of a film. A plasma display manufactured using the plasma display member according to claim 1. A method for manufacturing a plasma display member, comprising: forming a low refractive index layer having a lower refractive index than a phosphor after forming a phosphor layer. 7. The method according to claim 6, wherein the method of forming the low refractive index layer is any one of a vacuum deposition method, a sputtering method, and a plasma deposition method. The method for manufacturing a plasma display member according to claim 6, wherein the low refractive index layer is formed using a coating liquid containing fine particles.

Images