JP2006206641A - Vacuum ultraviolet phosphor, phosphor paste composition and plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum ultraviolet phosphor, a phosphor paste composition, and a plasma display using the same. <P>SOLUTION: The vacuum ultraviolet phosphor is composed of a phosphor such as an Mn-activated silicate phosphor represented by (A<SB>x</SB>B<SB>y</SB>)<SB>2</SB>SiO<SB>4</SB>(wherein A is at least one kind of Zn and Mg, and B is Mn), a metal oxide represented by M<SB>2</SB>O<SB>3</SB>, (wherein M is at least one metallic element of Y, La, and Al) and silicon oxide (SiO<SB>2</SB>), and at least part of the surface of the above phosphor is coated with the above M<SB>2</SB>O<SB>3</SB>and the above silicon oxide (SiO<SB>2</SB>) or the above phosphor is mixed with the above M<SB>2</SB>O<SB>3</SB>and the above silicon oxide (SiO<SB>2</SB>). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a phosphor for vacuum ultraviolet light (hereinafter referred to as a VUV phosphor) that is excited by vacuum ultraviolet light and used for a plasma display panel (hereinafter referred to as PDP), a rare gas discharge lamp or the like, and the phosphor. The present invention relates to a phosphor paste composition containing a phosphor and a PDP having a phosphor film containing the phosphor.

  In recent years, rare gases such as Ar, Xe, He, Ne, and Xe-Ne are sealed in a vacuum envelope such as glass, and the fluorescent film inside the envelope is formed by vacuum ultraviolet rays emitted by the discharge of the rare gas. Vacuum ultraviolet-excited light-emitting elements that emit light when excited (hereinafter referred to as VUV-excited light-emitting elements) have been put into practical use. Among these, PDP has been actively developed and improved as a color display device to which these VUV excitation light emitting elements are applied.

As the phosphor used in the VUV excitation light emitting element, for example, (Y, Gd) BO ₃ : Eu is used as a red light emitting phosphor, and LaPO ₄ : Ce, Tb or (Zn, Mn) is used as a green light emitting phosphor. Examples of the SiO ₄ and the blue light emitting phosphor include BaMgAl ₁₀ O ₁₇ : Eu, (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu, Mn, and the like.
In the case of a color PDP, full-color display can be performed by separately coating each phosphor that emits red, blue, and green in a matrix when excited by vacuum ultraviolet rays. (Y, Gd) BO ₃ : Eu is mainly used for the light emitting phosphor, Zn ₂ SiO ₄ : Mn is mainly used for the green light emitting phosphor, and BaMgAl ₁₀ O ₁₇ : Eu is mainly used for the blue light emitting phosphor. Yes.

By the way, since the phosphor for VUV is excited by ultraviolet rays having relatively high energy, it is said that the phosphor is deteriorated by ion bombardment such as residual gas ions generated by ultraviolet irradiation or discharge. In particular, Zn ₂ SiO ₄ : Mn, etc., whose surface of the phosphor is negatively charged, a chemical reaction proceeds due to adsorption of positive ions generated by discharge to the phosphor surface, and the phosphor deteriorates. It is said that the light emission luminance tends to decrease. Therefore, by coating the surface of the phosphor with a rare earth oxide or alumina (Patent Document 1) or by coating with a rare earth borate (Patent Document 2), the surface of the phosphor particles is made the same plus as the discharge ions in advance. A method has been proposed in which charging is performed and the influence of positive discharge ions on the phosphor is suppressed by repulsion of the polarity of the charging to suppress deterioration of the phosphor.

Moreover, the phosphor for VUV is applied in the process of producing PDP, in particular, the phosphor paste composition, in addition to the decrease in emission luminance due to deterioration when used as the above PDP or the like (when irradiated with vacuum ultraviolet rays). However, the phosphor is deteriorated in the step of drying and baking (baking step), and there is a problem that the light emission luminance is lowered. Therefore, as a method for suppressing a decrease in light emission luminance in these firing steps, for example, a method of improving the thermal degradation by applying a specific silicate coat to the phosphor or mixing a specific silicate with the phosphor ( Patent Document 3) is not intended to suppress the decrease in luminance due to heating of the phosphor, but in order to prevent the phosphor from deteriorating in luminance by suppressing the diffusion and adsorption of water to the phosphor surface. By coating a specific organic silicate on the surface of the BAM phosphor, which is the body, and Y ₂ O ₃ : Eu, which is the red phosphor, and providing a dense film, the diffusion and adsorption of water to the phosphor surface is suppressed, There has also been a proposal to prevent luminance deterioration of the phosphor (Patent Document 4).

SiO _x or silicates formed here, considering deterioration due to the discharge positive ions, BAM and Y ₂ O _3: Eu phosphor has surface is positively charged, is on the minus side ionized material It is acceptable to coat silicate or silicon oxide to some extent, but it is not preferable to deposit a lot. On the other hand, when applied to a negatively charged green-emitting phosphor ZnSiO ₄ phosphor, on the contrary, negative ionization is accelerated due to the ionic characteristics of SiO _x , resulting in an adverse effect. As described above, when the conventional technology, such as alumina, which is a positively charged material, and silicate coating are used in combination, there is a charge reciprocal despite their role, and the charge characteristics of the phosphor itself used. Therefore, the function of each coating material could not be used well, and the level of deterioration prevention according to the market needs of the phosphor could not be improved.

JP 2003-183650 A JP 2003-336047 A JP 2000-34478 A JP 2003-82342 A

  The present invention eliminates the above-mentioned problems associated with phosphors for VUV, causes little decrease in light emission luminance due to thermal deterioration of the film forming process of the phosphor film of the VUV excitation light emitting element, and discharges when irradiated with vacuum ultraviolet rays. Suppressing ion bombardment and adsorption of positive ions due to UV, phosphor for VUV with less degradation of emission brightness than conventional phosphors, and fluorescence with less decrease in emission brightness due to thermal degradation in the film formation process of phosphor film It is intended to provide a body paste composition and a PDP using the same.

In order to solve the above-mentioned problems, the present inventors made various pastes on the surface of a phosphor that emits light by excitation with vacuum ultraviolet rays, after irradiation with vacuum ultraviolet rays by coating the substance, and paste the phosphors As a result of diligent study on the effect of preventing the luminance degradation due to the baking treatment, the surface of the phosphor has a metal oxide composed of at least one of rare earth oxide and aluminum oxide and silicon oxide, particularly with a specific particle size. Spherical silicon oxide is coated on the surface of the phosphor particles, or these oxides are mixed with the phosphor to interpose the phosphor particles between the phosphor particles in a sterically hindered manner. Although the thermal degradation is improved by coating with a dense silicate coating, the disadvantage of conventional phosphors that negative charging that affects discharge degradation is accelerated. As a result, by combining with the metal oxide as a positive charging material, it is possible to suppress deterioration due to positive ion bombardment of discharge during use, and also suppress thermal deterioration in the manufacturing process, It came to the present invention which discovered that the said subject was solved.
The phosphor for VUV of the present invention, the phosphor paste composition, and the PDP are composed as follows.

(1) It consists of a phosphor, a metal oxide represented by M ₂ O ₃ and silicon oxide, and the oxide represented by M ₂ O ₃ and the silicon oxide are each at least on the surface of the phosphor. A phosphor for vacuum ultraviolet rays, which is partially coated or mixed with the phosphor.
(However, M represents at least one metal element in Y, La and Al.)
(2) The phosphor for vacuum ultraviolet ray according to (1), wherein the silicon oxide is a spherical particle.
(3) The phosphor for vacuum ultraviolet rays according to (1) or (2) above, wherein an average particle diameter of the silicon oxide is in a range of 10 to 200 nm.

(4) The content of the silicon oxide is in a range of 0.01 to 10 wt% with respect to the weight of the phosphor, for vacuum ultraviolet rays according to any one of (1) to (3), Phosphor.
(5) The total content of the metal oxide represented by M ₂ O _{3 is} in the range of 0.01 to 10 wt% with respect to the phosphor weight, (1) to (4) The phosphor for vacuum ultraviolet rays according to any one of (1).
(6) vacuum ultraviolet light according to any one of the phosphor above, wherein the a (A _x B _y) Mn-activated silicate phosphor represented by _{2 SiO 4 (1) ~ (} 5) Phosphor.
(However, A is at least one of Zn and Mg, B is Mn, and x + y represents a number in the range of 1.5 to 2.5)

(7) A phosphor paste composition in which a phosphor is dispersed in a binder resin, wherein the phosphor comprises the phosphor for vacuum ultraviolet rays according to any one of (1) to (6). A phosphor paste composition.

(8) A plasma display panel comprising a phosphor film containing the phosphor for vacuum ultraviolet rays according to any one of (1) to (6).

  By adopting the above configuration, the present invention charges the phosphor on the positive side with a larger charge amount, suppresses ion bombardment and gas adsorption due to vacuum ultraviolet irradiation, and suppresses reduction in luminous efficiency due to reduced luminance deterioration. In addition, it is possible to provide a VUV phosphor, a phosphor paste, and a PDP with improved luminous efficiency, which are suppressed in luminance reduction due to thermal degradation in the baking process when forming the fluorescent film.

Hereinafter, the present invention will be described in more detail.
The phosphor for VUV rays of the present invention is a phosphor that emits light by excitation with vacuum ultraviolet rays, a metal oxide represented by the general formula M ₂ O ₃ (where M represents at least one of Y, La, and Al). Hereinafter, this metal oxide is simply referred to as M ₂ O ₃ ) and silicon oxide, and the M ₂ O ₃ and silicon oxide are coated on at least a part of the surface of the phosphor particles, or the phosphor and It is characterized by being simply mixed.

In order to produce the phosphor for VUV of the present invention, a phosphor slurry in which the phosphor is dispersed in a solvent such as water is prepared, and a predetermined amount of M ₂ O ₃ and silicon oxide are added to the phosphor slurry. Then, after sufficiently stirring and mixing, the solvent can be removed and dried. At that time, when a slurry-like silicon oxide raw material such as colloidal silica is used as a silicon oxide source, a solution of a water-soluble metal salt such as zinc nitrate is further added to the phosphor slurry to thereby add M to the phosphor surface. _This is more preferable because it can increase the adhesion of ₂ O ₃ and silicon oxide.

Alternatively, the phosphor, a predetermined amount of powdered M ₂ O ₃ and silicon oxide can be milled with a ball mill or the like and mechanically mixed. However, in order to more surely suppress the luminance deterioration in the firing step in forming the phosphor film, M ₂ O ₃ or silicon oxide is directly attached or coated on at least a part of the phosphor surface in the phosphor slurry. The method of making it more preferable.

Which is the main constituent of VUV phosphor of the present invention, the phosphor of the general formula (A _x B _{y) 2} silicate phosphor represented by SiO ₄ (although, A is one of Zn and Mg least One type, B is Mn, x + y represents a number in the range of 1.5 to 2.5), general formula (M ¹ _1-x Eu _x ) O · a (M ² _1-y , _{Mn y) O · (5.5-0.5a)} Al 2 O 3 phosphor (wherein, M ¹ is at least one element selected from the group consisting of Ba, Sr and Ca, M ² is Eu ²⁺ represented by Mg and / or Zn, a represents a real number of 0 <a ≦ 2, and x and y represent a real number of 0 <x <1, 0 ≦ y <1, respectively. activated with aluminate phosphor with ^{_{Mn 2+, BaAl 12 O 19:}} Mn phosphor, BaMgAl ₁₀ O _17: Eu _{phosphor, (Ba, Sr) MgAl 10} O 17: Eu, Mn phosphor LaPO _4: Ce, including Tb phosphor, but also by any of the phosphors that can emit light by receiving vacuum ultraviolet radiation can be used, and a normal negatively charged Among these phosphors when using the formula (a _x B _y) silicate phosphor represented by ₂ SiO _4, is particularly especially effective in that it can enhance the resistance to ion impact.

M ₂ O ₃ , which is one component of the phosphor for VUV of the present invention, is not particularly limited with respect to its type as long as it is an oxide of Y, La, and Al.

Regarding silicon oxide, which is another component of the phosphor for VUV of the present invention, the silicon oxide source added to the phosphor together with M ₂ O ₃ is a solid silicon oxide, but a sol form such as colloidal silica. Silicon oxide may be used, but in the finally obtained phosphor for VUV, the phosphor surface is coated as spherical or nearly spherical particles (collectively referred to as spherical particles), or fluorescent. It is preferably mixed with the body.
When the particle diameter of silicon oxide coated or mixed with the phosphor is smaller than about 10 nm, negative charging is accelerated, and deterioration due to a decrease in the ion bombardment resistance of the phosphor is likely to occur. However, the effect of suppressing deterioration due to ion bombardment is reduced, and it becomes difficult to adhere to the phosphor. Accordingly, the silicon oxide used in the present invention preferably has a particle diameter in the range of about 10 to 200 nm.

When the contents of M ₂ O ₃ and silicon oxide in the phosphor for VUV of the present invention are less than 0.01% by weight with respect to the phosphor, respectively, the effect of suppressing luminance deterioration due to vacuum ultraviolet irradiation and the film forming process The effect of preventing thermal deterioration due to firing is small, and on the contrary, if it is more than 10% by weight, penetration of excitation light into the phosphor and extraction of light emission from the phosphor are hindered, and the luminous efficiency of the phosphor is decreased. Absent. Therefore, the contents of M ₂ O ₃ and silicon oxide in the phosphor for VUV of the present invention are preferably 0.01 to 10% by weight with respect to the phosphor, respectively.
The content ratio of M ₂ O ₃ and silicon oxide contained in the phosphor is preferably in the range of about 1: 5 to 5: 1, and more preferably in the range of 1: 2 to 2: 1. preferable.

  The phosphor paste composition of the present invention is produced in the same manner as the conventional phosphor paste composition except that the phosphor for VUV of the present invention is used as the phosphor powder. That is, the VUV phosphor of the present invention and the solvent in which the binder resin is dissolved are respectively added in predetermined amounts and sufficiently stirred and kneaded to disperse the phosphor in the solvent, and the amount of the solvent is appropriately adjusted. By adjusting to a viscosity suitable for the purpose of use.

  As the binder resin, a resin such as ethyl cellulose, nitrocellulose, acrylic resin, or polystyrene oxide is used according to the purpose of use of the obtained phosphor paste composition. Butyl carbitol, butyl carbitol acetate, terpineol, butyl acetate, ethyl acetate And uniformly mixed with a solvent such as methyl ethyl ketone. The blending amount of the phosphor in the phosphor paste composition is 5 to 80% by weight, preferably 20 to 60% by weight. Further, the blending amount of the binder resin is 4 to 50% by weight, preferably 8 to 50% by weight. Furthermore, the amount of the solvent added is 10 to 90% by weight, preferably 40 to 80% by weight.

  Further, in the case of the color PDP, the PDP of the present invention forms internal electrodes on a back plate such as a glass plate and provides a plurality of discharge cells by providing stripe-shaped or matrix-shaped barrier ribs. Three types of phosphor paste compositions of the present invention having different emission colors comprising red, green, and blue phosphors for VUV by a method such as screen printing on the bottom and inner wall of each partition wall constituting each discharge cell. It is composed of a glass plate or the like on which three kinds of fluorescent films having different emission colors are formed in each discharge cell and an internal electrode is formed at a predetermined distance from the back plate. The front plate is disposed oppositely, the periphery of the front plate and the back plate is sealed, the inside is evacuated, and then the rare gas is sealed to obtain the PDP of the present invention.

  The phosphor paste composition of the present invention can also be used for forming a fluorescent film of a rare gas lamp used for a light source for reading a scanner. A rare gas lamp is prepared by, for example, applying a phosphor paste composition whose viscosity is adjusted to the extent that it can flow into a tube from one end of a transparent glass thin tube having an inner diameter of 4 to 12 mm, at 100 to 200 ° C. After drying, baking is performed at 400 to 800 ° C. for 5 to 30 minutes to form a fluorescent film on the glass tube wall, and the inside of the glass tube is evacuated, and then a small amount of Ne98% -Xe2% mixed gas, He98 By sealing rare gas such as% -Xe2% mixed gas, sealing both ends of the tube, and then attaching electrodes to both ends of the glass capillary tube, inside and outside of the glass tube, or both sides facing outside of the glass tube Manufactured.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not restrict | limited to these.
[Example 1]
A phosphor slurry is prepared by adding 100 g of (Zn, Mn) ₂ SiO ₄ phosphor to 400 ml of ion-exchanged water and stirring sufficiently, and an aqueous yttrium oxide dispersion (concentration) having an average particle size of 33 nm in the phosphor slurry. After adding 1.5 ml of 10 w / v) and stirring for 30 minutes, 6.6 ml of a dispersion of colloidal silica having a particle size of 20 nm (trade name; Snowtex 20L, manufactured by Nissan Chemical) was added and stirred for 10 minutes. Further, an aqueous solution of Zn (NO ₃ ) ₂ containing 0.15 g of Zn in this phosphor slurry was dropped and stirred for 30 minutes, and then stirring was stopped. Next, this was dehydrated and dried at 120 ° C. for 12 hours to coat the surface of the (Zn, Mn) ₂ SiO ₄ phosphor with 0.15% Y ₂ O ₃ and 0.15% silicon oxide. Thus, a VUV phosphor of Example 1 was obtained.

[Example 2]
After stirring the phosphor water slurry obtained by sequentially adding the yttrium oxide aqueous dispersion and the colloidal silica dispersion to the (Zn, Mn) ₂ SiO ₄ phosphor water slurry, an aqueous solution of Zn (NO ₃ ) ₂ was added. Heating and evaporating while stirring without addition to reduce the amount of liquid, and finally evaporating to dryness to obtain a phosphor coated only with silicon oxide, and then 0.15% by weight on the phosphor coated with silicon oxide was obtained in Y ₂ O ₃ to the surface and mixed further in on-deposited silicon oxide Y ₂ O ₃ is mixed VUV phosphor of example 2.

Example 3
In the same manner as in Example 1 except that 1.5 ml of a lanthanum oxide aqueous dispersion having a particle size of 33 nm was added instead of the aqueous dispersion of yttrium oxide in Example 1, the surface of the (Zn, Mn) ₂ SiO ₄ phosphor was applied to the surface. The VUV phosphor of Example 3 coated with 0.15% La ₂ O ₃ and 0.15% silicon oxide was obtained.

Example 4
The same procedure as in Example 1 was performed except that 1.5 ml of a commercially available alumina sol dispersion (concentration: 10 w / v) having a particle size of 100 nm × 10 nm was added instead of the aqueous dispersion of yttrium oxide in Example 1. The VUV phosphor of Example 4 was obtained in which the surface of the (Zn, Mn) ₂ SiO ₄ phosphor was coated with 0.15% Al ₂ O ₃ and 0.15% silicon oxide.

Example 5
In the same manner as in Example 1 except that the input amount of the yttrium oxide dispersion was changed to 6.0 ml instead of 1.5 ml, 0.6% oxidation was performed on the surface of the (Zn, Mn) ₂ SiO ₄ phosphor. The phosphor for VUV of Example 5 to which yttrium and 0.15% silicon oxide were adhered was obtained.

Example 6
In Example 1, the amount of colloidal silica dispersion charged was changed from 6.6 ml to 26.4 ml, and an aqueous solution of Zn (NO ₃ ) ₂ containing 0.60 g of Zn instead of 0.15 g was added dropwise. In the same manner as in Example 1, 0.15% yttrium oxide and 0.6% silicon oxide were adhered to the phosphor on the surface of the (Zn, Mn) ₂ SiO ₄ phosphor. A phosphor was obtained.

Example 7
In the same manner as in Example 1, except that the input amount of the yttrium oxide dispersion was changed to 60 ml instead of 1.5 ml, 0.6% yttrium oxide was formed on the surface of the (Zn, Mn) ₂ SiO ₄ phosphor. Thus, a VUV phosphor of Example 5 in which 0.15% of silicon oxide was adhered to the phosphor was obtained.

Example 8
In Example 1, (Ba, Eu) MgAl was used in the same manner as in Example 1 except that (Ba, Eu) MgAl ₁₀ O ₁₇ phosphor was used instead of (Zn, Mn) ₂ SiO ₄ phosphor as the phosphor. The VUV phosphor of Example 8 was obtained by coating the surface of the ₁₀ O ₁₇ phosphor with 0.15% Y ₂ O ₃ and 0.15% silicon oxide.

[Comparative Example 1]
The (Zn, Mn) ₂ SiO ₄ phosphor used in Examples 1 to 7, which was not coated or mixed with M ₂ O ₃ or silicon oxide, was used as the VUV phosphor of Comparative Example 1.

[Comparative Example 2]
In Example 1, 1.5 ml of an aqueous yttrium oxide dispersion (concentration: 10 w / v) having a particle diameter of 33 nm was added to the prepared phosphor slurry, and an aqueous solution of colloidal silica and Zn (NO ₃ ) ₂ was not added. A VUV phosphor of Comparative Example 1 was obtained in the same manner as in Example 1 except that the surface of the (Zn, Mn) ₂ SiO ₄ phosphor was coated only with 0.15% Y ₂ O ₃ .

[Comparative Example 3]
In Example 1, Zn (NO ₃ ) ₂ containing 6.6 ml of a dispersion of colloidal silica (trade name; Snowtex 20L, manufactured by Nissan Chemical Co., Ltd.) having a particle diameter of 20 nm and 0.15 g of Zn in the prepared phosphor slurry. In the same manner as in Example 1 except that the aqueous yttrium oxide dispersion was not added and only 0.15% silicon oxide was added to the surface of the (Zn, Mn) ₂ SiO ₄ phosphor. A coated VUV phosphor of Comparative Example 3 was obtained.

[Comparative Example 4]
In Example 8, the (Ba, Eu) MgAl ₁₀ O ₁₇ phosphor used in Example 8 that was not coated or mixed with M ₂ O ₃ or silicon oxide was used as the VUV phosphor of Comparative Example 4.

[Evaluation of luminance deterioration of phosphor powder by heat treatment]
For the phosphor powders of the examples and comparative examples, the luminance maintenance ratio 1 of the emission luminance after the heat treatment was measured and used as an index for evaluating the degree of luminance deterioration due to the heat treatment of each phosphor. Table 1 shows the luminance maintenance rates 1 of the phosphors of Examples 1 to 8 and Comparative Examples 1 to 4 thus obtained.
The maintenance rate 1 in Table 1 is a percentage of the ratio of the emission luminance [Br1] of the phosphor powder before the heat treatment and the emission luminance [Br2] of the phosphor powder after the heat treatment {[ Br2] / [Br1]) × 100}, and the phosphor was heat-treated at a temperature of 550 ° C. for 1 hour. Further, the emission luminance of the phosphors is the emission luminance when each phosphor is irradiated with 146 nm vacuum ultraviolet rays.

In Table 1, the emission luminance [Br1] of each of the VUV phosphors of Examples 1 to 7 is the light emission before heat treatment of the (Zn, Mn) ₂ SiO ₄ phosphor of Comparative Example 1 in which nothing is coated on the surface. It is a relative value when the luminance [Br1] is 100, and the emission luminance [Br1] of the phosphor for VUV of Example 8 is (Ba, Eu) MgAl ₁₀ O of Comparative Example 4 with no surface coated. _It was expressed as a relative value when the emission luminance [Br1] of the ₁₇ phosphor before heat treatment was set to 100.

[Evaluation of charge amount of phosphor powder]
The charge amounts of the VUV phosphors of Examples 1 to 8 and Comparative Examples 1 to 4 were measured. Charge amount is 1g of each phosphor together with 10g of PVA (polyvinyl alcohol) powder in a glass sample bottle and mixed well for 30 minutes with a shaker. Table 1 shows the blow-off charge amount of each phosphor obtained as an index of the charge amount of each phosphor.

[Examples 9 to 16]
3 g of each VUV phosphor of Examples 1 to 8 was weighed, 2.5 g of ethyl cellulose resin, 1 g of butyl carbitol and 5.3 g of butyl carbitol acetate were added to each phosphor and kneaded. The phosphor pastes of Examples 9 to 16 were obtained.
[Comparative Examples 5 to 8]
In Example 9, the VUV phosphors of Comparative Examples 1 to 4 were used in place of the VUV phosphors of Example 1, respectively, in the same manner as the phosphor paste of Example 9, and Comparative Examples 5 to 8, respectively. A phosphor paste was obtained.

[Evaluation of luminance deterioration of phosphor paste in phosphor film forming process]
Each phosphor paste composition of Examples 9 to 16 and Comparative Examples 5 to 8 was applied to a glass plate to a thickness of 0.5 mm, dried at 120 ° C. for 30 minutes, and then fired at 450 ° C. for 30 minutes. Thus, a phosphor coating film was prepared and used as an evaluation sample (phosphor film) of each phosphor paste composition.
Next, for each of the prepared evaluation samples (phosphor films), the respective emission luminance [Br3] when irradiated with vacuum ultraviolet light of 146 nm is measured, the luminance maintenance rate 2 of each phosphor paste composition is obtained, and fluorescence is obtained. This was used as an index for evaluating the degree of luminance deterioration of each phosphor paste composition by heat treatment during film formation. Table 2 shows the luminance maintenance rates 2 of the phosphors of Examples 9 to 16 and Comparative Examples 5 to 8.

表２における輝度維持率２はそれぞれの蛍光体ペースト組成物の調製に用いた、熱処理を行う前の蛍光体粉体の発光輝度［Ｂｒ１］に対する、各評価サンプル（蛍光膜）の発光輝度［Ｂｒ３］の比の百分率｛（［Ｂｒ３］／［Ｂｒ１］）×１００｝により求めた値である。
なお、表２において実施例９〜１５及び比較例５〜７の各蛍光体ペースト組成物を使用して作製された各評価サンプル（蛍光膜）の発光輝度［Ｂｒ３］は比較例１のＶＵＶ用蛍光体粉体の発光輝度［Ｂｒ１］を１００とした時の相対値で示してあり、また、実施例１６及び比較例８の各蛍光体ペースト組成物を使用して作製された各評価サンプル（蛍光膜）の発光輝度［Ｂｒ３］は比較例８のＶＵＶ用蛍光体粉体の発光輝度［Ｂｒ１］を１００とした時の相対値で示してある。

The luminance maintenance rate 2 in Table 2 indicates the emission luminance [Br3] of each evaluation sample (phosphor film) with respect to the emission luminance [Br1] of the phosphor powder before the heat treatment used for the preparation of each phosphor paste composition. ] Ratio {([Br3] / [Br1]) × 100}.
In Table 2, the emission luminance [Br3] of each evaluation sample (phosphor film) produced using each phosphor paste composition of Examples 9 to 15 and Comparative Examples 5 to 7 is for VUV of Comparative Example 1. Each evaluation sample (shown as a relative value when the emission luminance [Br1] of the phosphor powder is set to 100) and each phosphor paste composition of Example 16 and Comparative Example 8 ( The emission luminance [Br3] of the phosphor film) is shown as a relative value when the emission luminance [Br1] of the phosphor powder for VUV of Comparative Example 8 is 100.

As is clear from the results in Table 1, the VUV phosphors of Examples 1 to 7 all have a large retention rate of 1 compared to the phosphor of Comparative Example 1 in which the surface is not coated. The degree of luminance deterioration with respect to heat deterioration is greatly improved and the charge amount is positive, and similarly, the surface has Y as compared with the phosphor of Comparative Example 4 where no coating treatment is applied to the surface. The VUV phosphor of Example 8 coated with ₂ O ₃ and silicon oxide has a large luminance maintenance factor of 1 and a large charge amount.

Further, as is apparent from the results in Table 2, the phosphor films formed using the phosphor paste compositions of Examples 9 to 15 were not subjected to any coating treatment on the surface, and M ₂ O ₃ and oxidation were not performed. The value of the maintenance factor 2 is large as compared with the phosphor film formed using the phosphor paste composition of Comparative Examples 5 to 7 made of the phosphor of Comparative Examples 1 to 3 that is not coated with any of silicon. Similarly, the surface of the phosphor film using the phosphor paste composition of Example 16 composed of the phosphor for VUV of Example 8 whose surface is coated with Y ₂ O ₃ and silicon oxide is covered at all. The value of the luminance maintenance factor 2 is larger than that of the phosphor film using the phosphor paste composition of Comparative Example 8 made of the phosphor paste composition of Comparative Example 4 that has not been treated.

  As described above, the phosphor for VUV of the present invention is greatly improved in the degree of luminance degradation due to thermal degradation, and the value of the charge amount is increased to the plus side, and the phosphor paste comprising the phosphor for VUV of the present invention. By applying a fluorescent film formed using the composition to the PDP, a PDP having very excellent characteristics in which luminance deterioration due to expected ion bombardment due to discharge and adsorption of positive ions is suppressed.

The phosphor for VUV and the phosphor paste composition using the same of the present invention suppress the ion bombardment caused by the irradiation of vacuum ultraviolet rays, thereby reducing the luminance degradation and the luminance degradation due to the thermal degradation in the baking process when forming the phosphor film. Therefore, it can be suitably used for a PDP or a rare gas lamp with high luminous efficiency.

Claims (8)

Consists of a metal oxide and silicon oxide represented by the phosphor and M ₂ O _3, and at least a portion of each of the M metal oxide and the silicon oxide represented by ₂ O ₃ is the phosphor surface A phosphor for vacuum ultraviolet rays, which is coated or mixed with the phosphor.
(However, M represents at least one metal element in Y, La and Al.) The phosphor for vacuum ultraviolet rays according to claim 1, wherein the silicon oxide is a spherical particle. The phosphor for vacuum ultraviolet rays according to claim 1 or 2, wherein the average particle diameter of the silicon oxide is in the range of 10 to 200 nm. The phosphor for vacuum ultraviolet rays according to any one of claims 1 to 3, wherein a content of the silicon oxide is in a range of 0.01 to 10 wt% with respect to a weight of the phosphor. 5. The total content of the metal oxide represented by M ₂ O _{3 is} in a range of 0.01 to 10 wt% with respect to the weight of the phosphor. The phosphor for vacuum ultraviolet rays described in 1. The phosphor (A _x B _{y) 2} VUV phosphor according to any one of claims 1 to 5, wherein the SiO ₄ is Mn-activated silicate phosphor represented by.
(However, A is at least one of Zn and Mg, B is Mn, and x + y represents a number in the range of 1.5 to 2.5) A phosphor paste composition obtained by dispersing a phosphor in a binder resin, wherein the phosphor comprises the phosphor for vacuum ultraviolet rays according to any one of claims 1 to 6. Composition. A plasma display panel comprising a phosphor film containing the phosphor for vacuum ultraviolet rays according to claim 1.