KR20080088464A - Fired aluminum-containing magnesium oxide powder - Google Patents

Abstract

A fired aluminum-containing magnesium oxide powder is provided to emit an ultraviolet light having a peak wavelength around wavelength 250 nm with a high efficiency when the powder is excited by an ultraviolet light generated by gas discharge of Xe gas. A fired aluminum-containing magnesium oxide powder has an aluminum content of 2-38% by mass, and is obtained by firing a powder mixture of gamma type aluminum powder and magnesium oxide source powder. The fired aluminum-containing magnesium oxide powder absorbs an ultraviolet light generated by gas discharge of Xe gas to emit an ultraviolet light having a peak wavelength in the range of wavelength 230-260 nm.

Description

Magnesium oxide fired powder containing aluminum {FIRED ALUMINUM-CONTAINING MAGNESIUM OXIDE POWDER}

The present invention relates to a magnesium oxide fired powder containing aluminum.

An AC plasma display panel (hereinafter also referred to as an AC PDP) generally includes a front plate serving as an image display surface and a rear plate disposed to face each other with a discharge space filled with discharge gas therebetween. The front plate consists of a glass substrate, a pair of discharge electrodes formed on the glass substrate, a dielectric layer formed to cover the discharge electrodes, and a dielectric protective layer formed on the surface of the dielectric layer. The back plate consists of a glass substrate, an address electrode formed on the glass substrate, a partition partitioning the discharge space formed to cover the glass substrate and the address electrode, and a red, green, and blue phosphor layer formed on the surface of the partition wall.

Generally as a discharge gas, the mixed gas of Xe (xenon) and Ne (neon) is used. In this mixed gas, Xe is a discharge gas and Ne is a buffer gas.

Magnesium oxide having a high secondary electron emission coefficient and excellent sputter resistance is widely used as a material for forming the dielectric protective layer in order to reduce the operating voltage of the AC type PDP and to protect the dielectric layer from plasma generated in the discharge space. It is becoming.

Conventionally, in the AC type PDP, for the purpose of improving the luminescence properties, the surface of the dielectric protective layer is excited by ultraviolet light generated by the discharge gas to excite the phosphor of the phosphor layer. By forming an ultraviolet light emitting layer that emits ultraviolet light having a wavelength and exciting the phosphor of the phosphor layer with ultraviolet light emitted from the discharge gas and ultraviolet light emitted from the ultraviolet light emitting layer, the luminous efficiency of the phosphor layer is improved. Is considered.

For example, Patent Document 1 has an average particle diameter of 500 angstroms or more, preferably 2000 angstroms or more, produced by vapor phase oxidation of steam generated by heating magnesium, preferably consisting of vapor phase magnesium oxide single crystal. An AC type PDP in which an ultraviolet light emitting layer is formed on the surface of the discharge space side of a dielectric protective layer is disclosed. And this ultraviolet light emitting layer emits the ultraviolet light which has a peak wavelength in the range of 230-250 nm, and it is disclosed that the brightness | luminance of a PDP will increase by excitation and light emission of fluorescent substance by the ultraviolet light of the wavelength.

On the other hand, Patent Document 2 discloses a dielectric layer protective layer (magnesium oxide film) of PDP manufactured using a dispersion solution prepared by mixing and kneading magnesium oxide and aluminum oxide. This patent document 2 has a description that the discharge start voltage is reduced as an effect of adding aluminum oxide. However, this patent document 2 has no description about the crystal structure of aluminum oxide, and there is no description that the obtained magnesium oxide thin film emits ultraviolet light by being excited by the ultraviolet light generated by the discharge gas of PDP. .

Patent Document 1: Japanese Unexamined Patent Publication No. 2006-59786

Patent Document 2: Japanese Unexamined Patent Publication No. 2006-173129

An object of the present invention is wavelength 250 when excited by ultraviolet light generated by gas discharge of Xe gas, which is useful as a material of an ultraviolet light emitting layer formed on a dielectric protective layer of a gas discharge light emitting device such as an AC type PDP. It is providing the magnesium oxide powder which emits the ultraviolet light which has a peak wavelength in the vicinity of nm with high efficiency.

MEANS TO SOLVE THE PROBLEM This inventor mixes (gamma) type aluminum oxide powder and magnesium oxide source powder so that the aluminum content after baking may be 2 to 38 mass%, Preferably, aluminum containing magnesium oxide obtained by baking at the temperature of 850 degreeC or more especially 10 minutes or more is preferable. The fired powder was excited by the ultraviolet light generated by the gas discharge of the Xe gas and found to emit ultraviolet light having a peak wavelength at a wavelength of 250 nm (wavelength of 230 to 260 nm) with high efficiency. The invention has been completed.

Therefore, this invention exists in the aluminum containing magnesium oxide powder in which the aluminum content obtained by baking the powder mixture of (gamma) type aluminum oxide powder and magnesium oxide source powder exists in the range of 2-38 mass%.

Preferred embodiments of the aluminum-containing magnesium oxide fired powder of the present invention are as follows.

(1) Aluminum content exists in the range of 5-35 mass%.

(2) Absorb the ultraviolet light generated by the gas discharge of the Xe gas and emit the ultraviolet light having the peak wavelength in the wavelength range of 230 to 260 nm.

(3) An ultraviolet light emitting layer is formed on the surface of the dielectric protective layer of the AC plasma display panel on the discharge space side.

The present invention also absorbs ultraviolet light generated by gas discharge of Xe gas, which consists of firing a powder mixture of? -Type aluminum oxide powder and magnesium oxide source powder, and has a peak wavelength in the range of wavelength 230 to 260 nm. There is also a method for producing an aluminum-containing magnesium oxide powder that emits ultraviolet light.

Preferable embodiments of the method for producing the aluminum-containing magnesium oxide fired powder of the present invention are as follows.

(1) A magnesium source powder is produced by oxidation of metal magnesium vapor.

(2) The baking temperature of a powder mixture exists in the range of 900-1500 degreeC.

The aluminum-containing magnesium oxide sintered powder of the present invention is excited by the ultraviolet light generated by the gas discharge of Xe gas, and the ultraviolet light having the peak wavelength at a wavelength of 250 nm (wavelength of 230 to 260 nm) with high efficiency Release. For this reason, by arranging the magnesium oxide film manufactured from the aluminum-containing magnesium oxide fired powder of the present invention in a discharge space of a gas discharge light emitting device such as an AC PDP or a phosphor lamp, the amount of ultraviolet light emitted in the discharge space is increased. It is possible to increase the amount of visible light emitted from the gas discharge light emitting device. The magnesium oxide film produced from the aluminum-containing magnesium oxide fired powder of the present invention is particularly useful as an ultraviolet light emitting layer formed on the surface of a gas dielectric protective layer of an AC type PDP.

The aluminum-containing magnesium oxide sintered powder of the present invention contains aluminum in a range of 2 to 38 mass%, particularly preferably in a range of 5 to 35 mass%. The aluminum-containing magnesium oxide fired powder of the present invention preferably has a BET specific surface area in the range of 0.1 to 30 m 2 / g, and particularly preferably in the range of 0.2 to 12 m 2 / g.

The aluminum-containing magnesium oxide fired powder of the present invention can be obtained by mixing a gamma-type aluminum oxide powder and a magnesium oxide source powder to obtain a powder mixture, and then firing the powder mixture. The firing temperature of the powder mixture is preferably 850 ° C or higher, more preferably 900 to 1500 ° C, still more preferably 1000 to 1500 ° C. Firing time becomes like this. Preferably it is 10 minutes or more, More preferably, it is the range of 10 minutes-2 hours, More preferably, it is the range of 20 minutes-2 hours. The firing of the powder mixture is, for example, at normal pressure under a condition of a temperature increase rate of 100 to 500 ° C / hour, and the temperature is raised to the firing temperature, and then the firing time is fired, and then the temperature reduction rate is 100 to 500 ° C /. It can carry out by cooling to room temperature on condition of time. In the firing atmosphere, an atmospheric atmosphere is usually used.

As magnesium oxide source powder, magnesium oxide powder and magnesium compound powder converted into magnesium oxide powder by heating can be used. Examples of the magnesium compound powder converted into the magnesium oxide powder by heating include magnesium hydroxide powder, basic magnesium carbonate powder, magnesium nitrate powder and magnesium acetate powder. It is preferable that magnesium oxide source powder is magnesium oxide powder, and it is preferable that magnesium oxide powder is magnesium oxide powder manufactured by vapor phase synthetic oxidation method. The gas phase synthetic oxidation method is a method of producing magnesium oxide powder by oxidizing metal magnesium by bringing metal magnesium vapor into an oxygen-containing gas in a gaseous phase.

The purity of the magnesium oxide source powder is preferably 99.95 mass% or more. It is preferable that magnesium oxide source powder exists in the range of 5-150 m <2> / g, especially 7-50 m <2> / g of BET specific surface areas. In addition, the particle diameter of magnesium oxide source powder is not specifically limited unless the effect of this invention is impaired.

It is preferable that the purity of (gamma) type aluminum oxide powder is 99.0 mass% or more. The particle diameter of the gamma-type aluminum oxide powder is not particularly limited as long as the effect of the present invention is not impaired.

The aluminum-containing magnesium oxide sintered powder of the present invention is excited by the ultraviolet light generated by the gas discharge of Xe gas and has high ultraviolet light (ultraviolet light having a peak wavelength in the range of 230 to 260 nm) near a wavelength of 250 nm. Emission with efficiency In addition, it is known that phosphor materials used in gas discharge light emitting devices such as AC type PDPs and phosphor lamps are excited by ultraviolet light near a wavelength of 250 nm as described in Patent Document 1 to emit visible light. For this reason, in the discharge space of the gas discharge light-emitting device which used the magnesium oxide film | membrane manufactured from the aluminum-containing magnesium oxide fired powder of this invention for discharge gas using Xe gas, such as an AC type PDP or a fluorescent lamp, especially a dielectric protective layer discharge When placed on the surface on the space side, the amount of ultraviolet light emitted in the discharge space by the gas discharge of Xe gas can be increased, and as a result, the amount of visible light emitted from the gas discharge light emitting device can be increased. Therefore, the aluminum-containing magnesium oxide sintered powder of this invention is especially useful for manufacture of the ultraviolet light emitting layer formed in the surface of the discharge space side of the dielectric protective layer of AC type PDP.

In addition, the aluminum-containing magnesium oxide fired powder of the present invention can be formed into a magnesium oxide film by using a known method such as a spray method or an electrostatic coating method, and the particle diameter thereof is within a range that does not impair the effect of the present invention. It is not particularly limited.

Example

Example 1

(Production of Fired Materials No. 1 to No. 8)

Magnesium oxide powder (2000A, manufactured by Ube Materials Co., Ltd., purity: 99.98 mass%, BET specific surface area: 8.7 m2 / g) and gamma type aluminum oxide powder (purity: 99.998 mass%) BET specific surface area: 61.4 m <2> / g) was mixed by the compounding quantity shown in following Table 1, and the powder mixture was obtained. The obtained powder mixture was put into a 25 mL alumina crucible, and the alumina crucible was covered with a lid, placed in an electric furnace, and the furnace temperature was raised to 1200 ° C. at a temperature increase rate of 240 ° C./hour, followed by heating and baking at that temperature for 30 minutes. .

Thereafter, the furnace temperature was cooled to room temperature at a temperature lowering rate of 240 ° C / hour. And the alumina crucible was taken out from the electric furnace, and the baking product powder (plastic No. 1-No. 8) which has BET specific surface area was obtained by the aluminum content shown in following Table 1. In addition, aluminum content was calculated | required by measuring the amount of aluminum in the solution prepared by melt | dissolving the baking powder in hydrochloric acid, by ICP emission analysis.

Comparative Example 1

(Production of Fired Materials No. 9 to No. 13)

In the same manner as in Example 1, except that the α-type aluminum oxide powder (purity: 99.99 mass%, BET specific surface area: 14.5 m 2 / g) was mixed with the magnesium oxide powder in the blending amount shown in Table 2 instead of the γ-type aluminum oxide powder. It was made to obtain the sintered powder (aluminum No. 9-No. 13) of the aluminum content shown in following Table 2.

[evaluation]

The ultraviolet light emission intensity | strength of the baked material powder (plastic materials No.1-No.13) manufactured in Example 1 and the comparative example 1 was measured by the following method.

[Ultraviolet light emission intensity]

Ultraviolet light generated by gas discharge of Xe gas was irradiated to the fired powder, and the ultraviolet light spectrum emitted from the fired powder was measured, and the maximum peak value near the wavelength of 250 nm (wavelength of 230 to 260 nm) was measured. It is calculated | required as ultraviolet light emission intensity.

1 and Table 3 below show the relationship between the aluminum content of the fired materials No. 1 to No. 12 and the ultraviolet light emission intensity. In addition, the ultraviolet light emission intensity shown in FIG. 1 and Table 3 is the relative value which made the ultraviolet light emission intensity of baking product No.13 100.

As apparent from the results of the ultraviolet light emission intensity shown in FIG. 1 and Table 3, in the fired powder prepared by using the gamma-type aluminum oxide powder as the aluminum source, fired products having an aluminum content in the range of 2 to 38% by mass. It can be seen that the powder has a higher luminescence intensity of ultraviolet light as compared with the fired powder produced by using the α-type aluminum oxide powder as the aluminum source.

Comparative Example 2

The magnesium oxide powder used in Example 1 was baked in the same manner as in Example 1 without adding the gamma-type aluminum oxide powder. As a result of irradiating the ultraviolet light generated by the gas discharge of the Xe gas with respect to the obtained fired product, no emission of ultraviolet light was observed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the relationship between the aluminum content and the ultraviolet light emission intensity | strength of the baking products powder manufactured in Example 1 and Comparative Example 1. FIG.

Claims (7)

The aluminum containing magnesium oxide powder in which the aluminum content obtained by baking the powder mixture of (gamma) type aluminum oxide powder and magnesium oxide source powder exists in the range of 2-38 mass%. The method of claim 1, Aluminum containing magnesium oxide powder whose aluminum content exists in the range of 5-35 mass%. The method of claim 1, The aluminum-containing magnesium oxide powder which absorbs the ultraviolet light produced | generated by the gas discharge of Xe gas, and emits the ultraviolet light which has a peak wavelength in the range of wavelength 230-260 nm. The method according to any one of claims 1 to 3, An aluminum-containing magnesium oxide powder for producing an ultraviolet light emitting layer formed on the surface of the discharge space side of the dielectric protective layer of an alternating current plasma display panel. absorbing the ultraviolet light generated by the gas discharge of Xe gas by firing a powder mixture of the γ-type aluminum oxide powder and the magnesium oxide source powder to emit ultraviolet light having a peak wavelength in the wavelength range of 230 to 260 nm. Method for producing aluminum-containing magnesium oxide powder. The method of claim 5, wherein The magnesium source powder is produced by oxidation of metal magnesium vapor. The method of claim 5, wherein The manufacturing method in which the baking temperature of a powder mixture exists in the range of 900-1500 degreeC.

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