KR20080072573A - A powder comprising blue light-emitting phosphor particles and preparation thereof - Google Patents

Abstract

A powder comprising blue light-emitting phosphor particles is provided to improve electroluminescent strength to a vacuum ultraviolet ray of the wavelength 172 nm corresponding to a Xe2 molecular ray emitted from Xe gas. A powder comprises blue light-emitting phosphor particles having a diopside crystal structure represented by the formula of CaMgSi2O6 : Eu. The Eu element on the particle surface is a mixture containing Eu^(2+) and Eu^(3+) in a ratio ranging from 12 : 88 to 35 : 65 under a condition in which the Eu^(2+) is present on the surface in an amount of 0.020 atom% or more, wherein the atom% means a percentage of the number of the Eu^(2+) present on the surface per the total number of Ca, Mg, Si, O, Eu^(2+), and Eu^(3+) present on the surface.

Description

Blue luminescent phosphor powder and its manufacturing method {A POWDER COMPRISING BLUE LIGHT-EMITTING PHOSPHOR PARTICLES AND PREPARATION THEREOF}

The present invention relates to a blue light emitting phosphor powder composed of blue light emitting phosphor particles having a diopside crystal structure containing europium as an activator, and a method for producing the same.

Plasma display panels (hereinafter referred to simply as PDPs) of color displays are obtained by irradiating vacuum ultraviolet rays generated by the discharge of the discharge gas to the phosphors to excite the phosphors to obtain blue, green, and red visible light, and the combination thereof. Display an image. Generally as a discharge gas, the mixed gas of Xe (xenon) gas and Ne (neon) gas is used. In this mixed gas, Xe gas discharges, and Ne gas is a buffer gas. The main vacuum ultraviolet rays generated by the discharge of the Xe gas are the resonance lines of Xe having a wavelength of 146 nm (also described as 147 nm) and the Xe ₂ having a wavelength of 172 nm (also described as 173 nm). Is the molecular beam of. Currently, the Xe resonance line of wavelength 146nm is mainly used for light emission of fluorescent substance.

Background Art Conventionally, blue light emitting phosphor powders having a basic compositional formula represented by BaMgAl ₁₀ O ₁₇ : Eu (hereinafter also referred to as BAM: Eu) are widely used as blue light emitting phosphors of PDP. However, the BAM: Eu blue light emitting phosphor powder differs from the decrease in the light emission luminance in the firing process at the time of PDP production and the time-dependent decrease in the light emission luminance due to repeated vacuum ultraviolet irradiation at the time of driving the PDP. There is a problem that it is large as compared with colored light emitting phosphor powder. In particular, the decrease in luminance over time during driving leads to deterioration of image quality due to color shift, leading to shortening of the lifespan of PDP as a product, and therefore improvement is required.

Since the decrease in the luminance of the BAM: Eu blue light-emitting phosphor powder is largely caused by the fact that BAM: Eu has a layered crystal structure, in a PDP which obtains light emission by high-energy vacuum ultraviolet excitation, the BAM: Eu blue light-emitting phosphor It is considered difficult to fundamentally improve the luminance fall of a powder. Therefore, there is a development of a low blue light-emitting fluorescent substance powder, lowering the temporal luminance proceeds, the passage of time in the die options side (CaMgSi ₂ O ₆₎ of a stable silicate mineral as a matrix, and a bivalent europium as activator, A blue light-emitting phosphor powder in which the basic composition formula contained is represented by CaMgSi ₂ O ₆ : Eu (hereinafter also referred to as CMS: Eu) has been developed.

However, although the CMS: Eu blue light emitting phosphor powder has a small decrease in luminance over time, there is a problem that the initial light emission luminance is lower than that of the BAM: Eu blue light emitting phosphor powder. For this reason, in the CMS: Eu blue light-emitting fluorescent substance powder, various examinations are made for the purpose of improving the initial light emission intensity.

Patent Document 1 discloses an invention in which a CMS: Eu blue light emitting phosphor powder is calcined in an oxidizing atmosphere, and the divalent europium concentration is 40 to 95% and the trivalent europium concentration is 5 to 60%. According to the example of this patent document, when the disclosed CMS: Eu blue light-emitting phosphor powder is used in a PDP in which discharge gas containing 5% of Xe gas is mixed with Ne gas as a main body, emission luminance is improved. In addition, this patent document discloses a method for producing a CMS: Eu blue light-emitting phosphor powder, in which a carbonate or an oxide serving as a calcium source, a magnesium source, a silicon source and a europium source is mixed and calcined in a reducing atmosphere in the presence of flux. Obtained by dissolving a method (solid state sintering method) or an organometallic salt or nitrate containing an element constituting the phosphor in water and then hydrolyzing to prepare a coprecipitate, and then spraying it in hydrothermal synthesis or firing in air or in a high temperature furnace. A method (liquid phase method) for baking powder in a reducing atmosphere is disclosed.

Patent Document 2 includes a crystalline phase and an amorphous phase having a thickness of 3 to 8 nm covering the surface of the crystalline phase, and the content rate of divalent europium to all europium in the surface layer in contact with the crystalline amorphous phase is 70%. A CMS: Eu blue light emitting phosphor powder composed of the above blue light emitting phosphor particles is disclosed. In this patent document, a calcium source powder, a magnesium source powder, a silicon source powder and a europium source powder are mixed at a ratio of producing CMS: Eu as a method for producing a CMS: Eu blue light emitting phosphor powder having the amorphous phase described above. Then, a method of firing in the presence of a fluorine source in a reducing atmosphere and firing the resulting fired powder in an acid treatment in contact with an acid or in the presence of oxygen is disclosed.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2003-238954

[Patent Document 2] Japanese Unexamined Patent Publication No. 2006-274244

As described above, various studies have been made aiming at improving the emission luminance of the CMS: Eu blue light emitting phosphor powder, but in order to improve the emission luminance of the PDP, further improvement of the emission luminance of the CMS: Eu blue light emitting phosphor powder is achieved. This is expected.

In particular, in recent years, in order to improve the light emission luminance of the PDP, increasing the concentration of the Xe gas in the discharge gas and increasing the amount of vacuum ultraviolet rays emitted from the Xe gas have also been studied. When the concentration of the Xe gas in the discharge gas is increased, not only the vacuum ultraviolet ray corresponding to the resonance line of Xe but also the amount of generation of the vacuum ultraviolet ray having a wavelength of 172 nm corresponding to the Xe ₂ molecular beam increases.

It is therefore an object of the present invention to provide a CMS: Eu blue light emitting phosphor powder having an improved luminescence intensity against vacuum ultraviolet rays having a wavelength of 172 nm, which corresponds to an Xe ₂ molecular beam emitted from Xe gas.

MEANS TO SOLVE THE PROBLEM This inventor calcinates the powder mixture which mixed calcium source powder, magnesium source powder, and silicon source powder in presence of a fluorine source, produces | generates calcium magnesium silicon-containing powder, and then produces | generates the calcium magnesium silicon-containing powder produced and mixing the europium source powder, and by a method of firing in a reducing atmosphere, and a europium (Eu) elements present on the particle surface, a divalent europium (Eu ^{2 +)} amount is more than 0.020 atom%, and a divalent organic ropyum ( Eu ^{2 +)} and the trivalent europium (Eu ^{+ 3)} 12: 88 ~ 35: 65 ratio range (Eu ^{2 +} a: Eu ³⁺⁾ is a mixture which contains a CMS: Eu powder made of a blue light emitting phosphor particles It was found that the powder can improve the emission intensity by excitation of vacuum ultraviolet rays having a wavelength of 172 nm while maintaining the emission intensity due to excitation of vacuum ultraviolet rays having a wavelength of 146 nm. In reached.

Accordingly, the present invention, the base composition formula CaMgSi ₂ O _6: a powder composed of a blue light-emitting fluorescent substance particles having a die options side crystal structure represented by Eu, the Eu elements of the particle surface, Eu ^{2 +} is 0.020 ~ 0.10 on the surface in an amount of at.% (provided that at%, the mean number of percentage of Eu ^{2 +} present in the Ca, Mg, Si, O, Eu ^{2 +,} and the total number per surface of Eu ^{3 +} from the surface) under present conditions, the Eu ^{2 +} and Eu ^{3 +} 12: is a powder, characterized in that a mixture containing a ratio ranging from 65: 88-35.

Preferred embodiments of the blue light emitting phosphor of the present invention are as follows.

(1) Eu ^{2 +} and Eu ^{3 +} ratio of 20: in the range of 65: 80 to 35.

⁽²⁾ Eu 2 ⁺ is present in an amount of 0.020 ~ 0.10% by atom on the surface.

(3) Eu ^{2 +} is present in an amount of 0.030 ~ 0.080% by atom on the surface.

(4) Eu ^{3 +} is present in an amount of 0.0050 ~ 0.15% by atom on the surface.

The present invention is also obtained by mixing calcium source powder, magnesium source powder and silicon source powder in a ratio of producing blue light emitting phosphor particles having a diopside crystal structure represented by CaMgSi ₂ O ₆ : Eu as a basic composition formula. By firing the powder mixture in the presence of a fluorine source, the first firing step of obtaining a calcium-magnesium-silicon-containing powder, the powder obtained in the first firing step, and the europium source powder are mixed and calcined in a reducing atmosphere to emit blue light-emitting fluorescent particles. the base formula made by a second calcination step for obtaining a powder consisting of a CaMgSi ₂ O _6: has in the manufacture method of a powder consisting of a blue light-emitting fluorescent substance particles having a crystal structure represented by the die-side options Eu.

Preferred embodiments of the production method of the present invention are as follows.

(1) The baking temperature in a 1st baking process exists in the range of 600-1000 degreeC, and the baking temperature in a 2nd baking process is in the range of 900-1500 degreeC.

(2) It also includes the step of making the powder obtained by the 2nd baking process contact with an acid, and the process of baking the acid-treated powder at the temperature of 400-1500 degreeC in presence of oxygen.

As for CMS: Eu blue light-emitting fluorescent substance powder, the fall of luminance with time is hard to occur compared with BAM: Eu blue light emitting fluorescent substance powder. And, according to the present invention CMS: Eu blue phosphor powder is particularly high in light emission intensity of the vacuum ultraviolet light having a wavelength corresponding to 172㎚ Xe ₂ molecular beam. For this reason, the CMS: Eu blue light emitting phosphor powder of the present invention is a blue light emitting fluorescence of a PDP or a rare gas lamp using a discharge gas having a high Xe gas concentration (for example, a discharge gas having a Xe gas partial pressure of 10% or more of the total pressure). It is particularly useful as a material.

Moreover, especially by using the manufacturing method of this invention, CMS: Eu <^{2> +} blue light emitting fluorescent substance powder with high emission intensity with respect to the vacuum ultraviolet-ray of wavelength 172nm can be industrially advantageously manufactured.

CMS of the invention: Eu blue phosphor powder, the Eu elements of the particle surface, Eu ^{2 +} that is at least 0.020 atom% amount, Eu ^{2 +} and Eu ^{3 +} a 12: to 65 range, preferably: 88-35 Consists of CMS: Eu blue light emitting fluorescent substance particles which are mixtures containing in the ratio of 20: 80-35: 65. The ratio of Eu ^{2 +} and Eu ^{3 +} 20: is preferably in the range of 65: 80 to 35. The amount of the particle surfaces of Eu ^{2 +} preferably in the range of 0.020 ~ 1.0 atomic%, more preferably in the range of 0.020 ~ 0.10 at%, and the range of 0.030 ~ 0.080 at.% Is particularly preferred. The amount of the particle surfaces of the Eu ^{+ 3,} preferably in the range of 0.0050 ~ 0.15 at.%, Particularly preferably in the range of 0.050 ~ 0.14% by atom.

Here, the amount of the of the Eu ^{2 +} and Eu ^{3 +} particle surface, CMS: Eu blue all the elements - calcium, which is present on the surface of the light-emitting housing particles (Ca), magnesium (Mg), silicon (Si), oxygen (O), and a divalent europium (Eu ^{+ 2)} and a trivalent europium (Eu ^{+ 3)} means the total number of the party, and the number of percentage of Eu ^{2 +} and Eu ^{3 +} from the surface of the atoms of. The total number of atoms on the particle surface can be determined from the energy of photoelectrons emitted when X-rays are irradiated on the particle surface using ESCA (Electron Spectroscopy for Chemical Analysis).

In the CMS: Eu blue light emitting phosphor powder of the present invention, the divalent europium substitutes a part of the calcium of the diopside (CaMgSi ₂ O ₆ ) to form CMS: Eu, and the trivalent europium is a calcium europium silicate ( It is thought to form Ca ₂ Eu ₈ (SiO ₄ ) ₆ O ₂ ). In the CMS: Eu blue light-emitting phosphor powder of the present invention, the content of calcium europium silicate is calcium europium with respect to the X-ray diffraction peak of the (22-1) plane (JCPDS card: 11-654) of the diopside. It is preferable that the intensity ratio of the X-ray diffraction peaks on the (211) plane of the silicate (JCPDS card: 29-320) does not exceed 0.03.

The CMS: Eu blue light emitting phosphor powder of the present invention is a calcium source powder, magnesium source powder, and silicon in a ratio of producing blue light emitting phosphor particles having a diopside crystal structure represented by the basic compositional formula CaMgSi ₂ O ₆ : Eu. The raw powder is mixed, and the obtained powder mixture is calcined in the presence of a fluorine source to mix the first firing step of obtaining calcium magnesium silicon-containing powder, the powder obtained at the first firing step, and the europium source powder to reduce the atmosphere. It can manufacture advantageously by the method which consists of a 2nd baking process made to bake under.

Examples of the calcium source powder include calcium carbonate powder, calcium oxide powder, calcium hydroxide powder, calcium nitrate powder and calcium chloride powder. It is preferable that the purity of a calcium source powder is 99 mass% or more, and it is especially preferable that it is 99.9 mass% or more. It is preferable that the average particle diameter measured by the laser diffraction scattering method exists in the range of 0.1-10.0 micrometers, and, as for a calcium source powder, it is especially preferable to exist in the range which is 0.1-5.0 micrometers.

Examples of magnesium source powders include magnesium oxide powder, magnesium carbonate powder, magnesium hydroxide powder, magnesium nitrate powder, and magnesium chloride powder. It is preferable that the purity of magnesium source powder is 99 mass% or more, and it is especially preferable that it is 99.9 mass% or more. It is particularly preferable that the magnesium source powder is a gas phase method magnesium oxide obtained by a method of contacting metal magnesium vapor with oxygen (gas phase oxidation reaction method). It is preferable that the average particle diameter measured by the laser diffraction scattering method exists in the range of 0.1-10.0 micrometers, and, as for magnesium source powder, it is especially preferable to exist in the range which is 0.1-3.0 micrometers.

Silicon dioxide powder is mentioned as an example of a silicon source powder. It is preferable that the purity of silicon dioxide powder is 99 mass% or more, and it is especially preferable that it is 99.5 mass% or more. It is preferable that the average particle diameter measured by the laser diffraction scattering method exists in the range of 0.5-200 micrometers, and, as for silicon dioxide powder, it is especially preferable to exist in the range which is 1-100 micrometers.

Examples of the europium source powder include europium oxide powder and europium chloride powder. The purity of the europium source powder is preferably 99% by mass or more, and particularly preferably 99.5% by mass or more. It is preferable that the average particle diameter measured by the laser diffraction scattering method exists in the range of 0.1-10.0 micrometers, and it is especially preferable that the europium source powder exists in the range of 0.1-5.0 micrometers.

The fluorine source acts as a flux (flux). It is preferable that a fluorine source is the powder of the fluoride of arbitrary metals which form CMS: Eu blue light emitting fluorescent substance powder. Specifically, the fluorine source is preferably calcium fluoride powder and magnesium fluoride powder, and particularly preferably calcium fluoride powder. It is preferable that the average particle diameter measured by the laser diffraction scattering method exists in the range of 0.1-100.0 micrometers, and it is especially preferable that the fluorine source powder exists in the range of 0.1-10.0 micrometers.

In preparing the CMS: Eu blue light emitting phosphor powder of the present invention, first, the calcium source powder, the magnesium source powder, the silicon source powder, and the fluorine source are mixed into a powder mixture in a ratio of producing CMS: Eu blue light emitting phosphor particles. After that, it is calcined to produce a calcium-magnesium-silicon-containing powder (first calcining step). The blending ratio of calcium source powder, magnesium source powder, silicon source powder, and fluorine source is 0.900 to 1.00: 1: 1.900-1 in the ratio of calcium (Ca), magnesium (Mg) and silicon (Si) in the powder mixture in molar ratio. It is an amount which becomes 2.100 (Ca: Mg: Si), and it is preferable that it is a ratio which the amount of fluorine becomes in the range of 0.023-0.048 mol with respect to 1 mol of magnesium, especially the range of 0.023-0.042 mol. It is preferable to perform baking of the powder mixture in a 1st baking process in air | atmosphere atmosphere. It is preferable that baking temperature exists in the range of 600-1000 degreeC. The firing time is generally in the range of 1 to 100 hours.

The calcium, magnesium, and silicon-containing powders obtained in the first firing step are produced as oxides or mixtures of oxides and carbonates.

In the present invention, next, the calcium-magnesium-silicon-containing powder and the europium source powder are mixed and, for example, hydrogen-containing gas such as argon gas or nitrogen gas containing hydrogen gas in the range of 1 to 10% by volume. It is calcined in a reducing atmosphere by to prepare a CMS: Eu blue light emitting phosphor powder (second firing step). The molar ratio of calcium (Ca) contained in the calcium magnesium silicon-containing powder and europium (Eu) contained in the europium source powder is Eu / (Ca + Eu). ), The ratio is preferably in the range of 0.005 to 0.100, and particularly preferably the ratio is in the range of 0.015 to 0.100. It is preferable that the baking temperature in a 2nd baking process exists in the range of 900-1500 degreeC, and it is especially preferable to exist in the range which is 900-1300 degreeC. The firing time is generally in the range of 1 to 100 hours.

CMS: Eu blue light-emitting fluorescent substance powder obtained as mentioned above may perform recalcination process at the temperature of 400-1500 degreeC in presence of oxygen, after performing the acid process which makes contact with an acid solution.

Hydrochloric acid aqueous solution, nitric acid aqueous solution, and sulfuric acid aqueous solution are mentioned as an example of the acid solution used for an acid treatment. Especially an aqueous hydrochloric acid solution is preferable. The concentration of the acid solution is preferably in the range of 0.01 to 10 mol / l, and particularly preferably in the range of 0.05 to 5 mol / l. It is preferable that the liquid temperature of an acid solution exists in the range of 20-80 degreeC, and it is especially preferable to exist in the range which is 30-60 degreeC. It is preferable to perform the contact of the calcined powder and the acid solution under stirring. The contact time of the calcined powder and the acid solution is preferably in the range of 10 minutes to 10 hours.

The refiring process can be performed in an atmospheric atmosphere. It is preferable to exist in the range of 500-1500 degreeC, and it is especially preferable to exist in the range of 550-1000 degreeC. It is preferable that baking time is the range of 10 minutes-10 hours.

The measurement of the average particle diameter of each raw material powder used in the present Example was measured with the following method.

[Measurement of Average Particle Size]

0.3 g of the raw material powder is added to 50 ml of ethanol, followed by stirring to prepare a uniform dispersion. The dispersion liquid is dispersed for 3 minutes under the condition of an output of 400 kV using an ultrasonic homogenizer. The dispersion liquid after the dispersion treatment is measured for particle size distribution using a laser diffraction scattering particle size distribution analyzer (Microtrack HRA manufactured by Nikkiso Co., Ltd.) to obtain an average particle diameter based on volume.

Example 1

Calcium carbonate powder (manufactured by Ube Materials, Inc., purity 99.99% by mass, average particle size: 3.87 µm) 16.47 g, calcium fluoride powder (purity: 99.9) so that the molar ratio of Ca: Mg: Si is 0.988: 1: 1.00. Mass%, average particle size: 2.70 μm) 0.20 g, magnesium oxide powder (manufactured by Ube Materials Co., Ltd., vapor phase magnesium oxide, purity: 99.98 mass%, average particle diameter: 0.5 μm) 6.67 g, and silicon dioxide powder (Nippon Aerosil Co., Ltd. product, purity 99.9 mass%, average particle diameter: 49.8 micrometers) Weighed 20.00g, and wetted for 24 hours by the ball mill using the nylon ball (diameter 10mm) in which the iron core was contained in ethanol solvent. Mixed. After the slurry of the obtained powder mixture was dried and ethanol was removed, the powder mixture was placed in an aluminum crucible and calcined at an temperature of 900 ° C. for 3 hours to prepare calcium magnesium silicon-containing powder (first firing step). ).

Next, 15.0 g of said calcium magnesium silicon-containing powder and europium oxide powder (produced by Shin-Etsu Chemical Co., Ltd., purity: 99.9) so that the molar ratio of Ca: Eu: Mg: Si is 0.988: 0.02: 1: 1.00. 0.244 g of mass% and an average particle diameter of 2.71 µm were weighed and wet-mixed for 24 hours by a ball mill using a nylon ball (diameter 10 mm) containing an iron core in an ethanol solvent. After the slurry of the obtained powder mixture was dried and ethanol was removed, the powder mixture was placed in an aluminum crucible and calcined at a temperature of 1050 ° C. for 3 hours in a mixed gas atmosphere of 2 vol% hydrogen-98 vol% argon (second firing). fair).

2 g of the obtained fired powder was immersed in 300 ml of hydrochloric acid aqueous solution having a concentration of 1 mol / L and a liquid temperature of 40 ° C, and stirred for 3 hours while maintaining the liquid temperature of the hydrochloric acid aqueous solution at 40 ° C for acid treatment. After completion of the acid treatment, the fired powder was taken out of an aqueous hydrochloric acid solution, washed with ion exchanged water, and dried. Subsequently, the calcined powder was placed in an aluminum crucible and heated at a temperature of 600 ° C. for 1 hour in an air atmosphere to carry out a refiring process.

X-ray diffraction patterns of the calcined powders subjected to refiring were measured. As a result, X-ray diffraction of diopside (CaMgSi ₂ O ₆ ) and calcium europium silicate (Ca ₂ Eu ₈ (SiO ₄ ) ₆ O ₂ ) The pattern was detected. Intensity of X-ray diffraction peaks of (211) plane of calcium europium silicate (JCPDS card: 29-320) with respect to X-ray diffraction peaks of (22-1) plane of diopside (JCPDS card: 11-654) The ratio was 0.02, and it was confirmed that the fired powder consisted of particles having most of the diopside crystal structure.

The amount of Eu ^{2 +} and Eu ^{3 +} of the particle surfaces of the fired powder were measured by ESCA (1600S X-ray photoelectron spectrometer, manufactured by PHI). The results are shown in Table 1.

For the fired powder, the emission spectrum at the excitation wavelength 172 nm and the emission spectrum at the excitation wavelength 146 nm were measured with a spectrophotometer. Table 1 shows the maximum emission intensity (maximum value of the peak of the emission spectrum) of the obtained emission spectrum.

Example 2

The compounding quantity of the europium oxide powder with respect to 15.0 g of calcium, magnesium, and silicon-containing powders obtained in the first firing step of Example 1 was 0.488 g so that the molar ratio of Ca: Eu: Mg: Si was 0.988: 0.04: 1: 2.00. Except what was done, the baking product powder was produced like Example 1, and the acid treatment and the recalcination process were performed.

As a result of measuring the X-ray diffraction pattern of the obtained fired powder, X-ray diffraction patterns of diopside (CaMgSi ₂ O ₆ ) and calcium europium silicate (Ca ₂ Eu ₈ (SiO ₄ ) ₆ O ₂ ) were detected. . The intensity ratio of the X-ray diffraction peak of the (211) plane of calcium europium silicate to the X-ray diffraction peak of the (22-1) plane of the diopside is 0.02, and most of the fired powder is diopside It was confirmed that the particles consist of particles having a crystal structure.

Performing Eu ^{2 +,} and the amount of Eu ^{3 +} of the particle surfaces of the fired powder was measured in the same manner as in Example 1. The results are shown in Table 1. In addition, the emission spectrum of the fired powder was measured in the same manner as in Example 1. Table 1 shows the maximum emission intensity of the obtained emission spectrum.

Comparative Example 1

According to the method of the said patent document 2, CMS: Eu blue light emitting fluorescent substance powder was manufactured. 8.24 g of calcium carbonate powder, 0.10 g of calcium fluoride powder, 0.293 g of europium oxide powder, 3.33 g of magnesium oxide powder, and 10.00 g of silicon dioxide powder, so that the molar ratio of Ca: Eu: Mg: Si is 0.988: 0.02: 1: 2.00. Were weighed and wet-mixed by a ball mill using a nylon ball (diameter 10 mm) containing an iron core in an ethanol solvent for 24 hours. After the slurry of the obtained powder mixture was dried and ethanol was removed, the powder mixture was placed in an aluminum crucible and calcined at a temperature of 1050 ° C. for 3 hours in a mixed gas atmosphere of 2 vol% hydrogen-98 vol% argon.

The obtained calcined powder was subjected to an acid treatment and a refire treatment in the same manner as in Example 1.

As a result of measuring the X-ray diffraction pattern of the obtained fired powder, X-ray diffraction patterns of diopside (CaMgSi ₂ O ₆ ) and calcium europium silicate (Ca ₂ Eu ₈ (SiO ₄ ) ₆ O ₂ ) were detected. . The intensity ratio of the X-ray diffraction peak of the (211) plane of calcium europium silicate to the X-ray diffraction peak of the (22-1) plane of the diopside is 0.02, and most of the fired powder is diopside It was confirmed that the particles consist of particles having a crystal structure.

Performing Eu ^{2 +,} and the amount of Eu ^{3 +} of the particle surfaces of the fired powder was measured in the same manner as in Example 1. The results are shown in Table 1. In addition, the emission spectrum of the fired powder was measured in the same manner as in Example 1. Table 1 shows the maximum emission intensity of the obtained emission spectrum.

*) The maximum light emission intensity is a relative value obtained by setting the value of Comparative Example 1 to 100.

As is apparent from the results in Table 1, the present invention is, Eu elements of the particle surface according to, Eu ²⁺ is under the conditions present in an amount of at least 0.020 at% on the surface, and Eu ^{2 +} Eu ^{3 +} 12: 88 to 35: mixture of CMS containing a ratio ranging from 65: powder consisting of Eu blue light emitting phosphor particles, manufactured by the known production method CMS: in the particle surface, compared with the Eu blue light-emitting fluorescent substance powder Eu ^{2 +} and Eu Light emission by excitation of vacuum ultraviolet rays having a wavelength of 172 nm corresponding to the Xe ₂ molecular beam without reducing the amount of ^{3 +} , particularly the amount of Eu ^{2 +} present and decreasing the emission luminance to the wavelength 146 nm corresponding to the Xe resonance line The brightness is improved.

Claims (8)

The basic formula CaMgSi ₂ O _6: die options represented by the Eu side (diopside) as a powder made of a blue light-emitting fluorescent substance particles having a crystal structure, the particles are Eu element of the surface, Eu ^{2 +} is at least 0.020 at% on the surface (where , at.%, under the conditions present in an amount of means that a percentage of the number of Eu ^{2 +)} present on the Ca, Mg, Si, O, Eu ^{2 +,} and the total number per surface of Eu ^{3 +} from the surface , Eu ^{2 +} and Eu ^{3 +} 12: 88 ~ 35: powder, characterized in that a mixture containing a ratio of 65 range. The method of claim 1, Powder in the range of 65: Eu ^{+ 2} and ^{3 +} Eu ratio of 20: 80 to 35. The method of claim 1, Eu ²⁺ powder is present in an amount of 0.020 ~ 0.10% by atom on the surface. The method of claim 1, Eu ²⁺ powder is present in an amount of 0.030 ~ 0.080% by atom on the surface. The method of claim 1, Eu ^{3 +} the powder is present in an amount of 0.0050 ~ 0.15% by atom on the surface. A powder mixture obtained by mixing calcium source powder, magnesium source powder and silicon source powder in a ratio of producing blue light emitting phosphor particles having a diopside crystal structure represented by the basic composition formula CaMgSi ₂ O ₆ : Eu. Is calcined in the presence of a fluorine source, the first firing step of obtaining calcium-magnesium-silicon-containing powder, the powder obtained in the first firing step and the europium source powder are mixed and calcined in a reducing atmosphere to form blue-emitting fluorescent particles. the basic formula of claim 2 comprising a firing step for obtaining a powder CaMgSi ₂ O _6: process for producing a powder made of a blue light-emitting fluorescent substance particles having a crystal structure represented by the die-side options Eu. The method of claim 6, The manufacturing method of the powder whose baking temperature in a 1st baking process is in the range of 600-1000 degreeC, and the baking temperature in a 2nd baking process is in the range of 900-1500 degreeC. The method of claim 6, Furthermore, the manufacturing method of the powder containing the process of contacting the powder obtained by the 2nd baking process with an acid, and the process of baking the acid-treated powder in the presence of oxygen at the temperature of 400-1500 degreeC.