JP2012158692A - Laminate having phosphor layer, light emitting device, and blue-light emitting phosphor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the emission intensity of laminate having a phosphor layer containing a blue-light emitting phosphor by suppressing the decrease in emission intensity of the SMS blue-light emitting phosphor due to heating during formation of the phosphor layer.SOLUTION: The blue-light emitting phosphor includes SrMgSiOcrystal phase activated by Eu as the main component and SrMgSiOcrystal phase as the sub component. Ratio B/(A+B) is in the range of 0.02-0.20 when A is assumed as the diffraction intensity of the SrMgSiOcrystal phase and B is assumed as the diffraction intensity of the SrMgSiOcrystal phase each obtained by X-ray diffraction using CuKα rays.

Description

  The present invention relates to a laminate having a phosphor layer containing a blue-emitting phosphor. The present invention also relates to a light-emitting device including the laminate and an excitation light source that emits excitation light for exciting the phosphor in the phosphor layer of the laminate. The present invention further relates to a blue-emitting phosphor that can be advantageously used as a raw material for the phosphor layer.

As a light emitting device that emits visible light by irradiating phosphor such as vacuum ultraviolet light or ultraviolet light to excite the phosphor, AC plasma display panel (AC type PDP), cold cathode fluorescent lamp (CCFL) ) And white light emitting diodes (white LEDs) are known. As a blue light emitting source of these light emitting devices, a blue light emitting phosphor (hereinafter, also referred to as an SMS blue light emitting phosphor) whose main component is an Sr ₃ MgSi ₂ O ₈ crystal phase (merwinite crystal phase) activated by Eu is known. It has been.

  In the AC type PDP and CCFL, the phosphor is used in the state of a phosphor layer formed in a layer on the substrate. The phosphor layer is generally formed by applying a phosphor dispersion liquid in which a phosphor is dispersed on a substrate, drying the coated layer obtained, and then heating. Usually, an organic binder is added to the phosphor dispersion, and the coating layer is heated in an air atmosphere in order to volatilize or decompose and remove the organic binder. In the phosphor layer thus formed, the phosphor is required to have excellent heat resistance so that the emission intensity of the phosphor does not decrease due to heating during the formation of the phosphor layer.

  Patent Document 1 describes an SMS blue light emitting phosphor having a crystal lattice distortion of 0.055% or less. According to Patent Document 1, an SMS blue light emitting phosphor having a crystal lattice distortion as small as 0.055% or less has high light emission intensity and heat resistance, and therefore various fluorescent light emission such as mercury discharge lamps and plasma display panels. It can be advantageously used as a blue light source of the device.

  On the other hand, in the white LED, the phosphor is used in a state of being dispersed in a transparent matrix such as glass.

In Patent Document 2, in a wavelength converter in which a red light emitting phosphor, a blue light emitting phosphor and a green light emitting phosphor are dispersed in a transparent matrix used for an LED lamp, the blue light emitting phosphor contains Eu as a main crystal. M ¹ ₃ MgSi ₂ O ₈ type crystal (M ¹ is Sr, Sr and Ba, or Sr and Ca), and M ¹ ₂ MgSi ₂ O ₇ type crystal as the _second crystal, 2θ = When the X-ray diffraction intensity of the peak detected at 31.5 ° to 33 ° is A, and the X-ray diffraction intensity of the peak detected at 2θ = 28 ° to 30.5 ° of the second crystal is B , 0.002 ≦ B / (A + B) ≦ 0.052 is used. According to Patent Document 2, it is said that a blue light-emitting phosphor having B / (A + B) in the above range exhibits high emission intensity. In addition, this patent document 2 does not describe the heat resistance of the blue light emitting phosphor.

JP 2010-209206 A JP 2010-6850 A

  The objective of this invention is providing the laminated body which has a fluorescent substance layer containing the SMS blue light emission fluorescent substance with high luminous intensity, and the light-emitting device provided with this laminated body. That is, an object of the present invention is to improve the emission intensity of the laminate by suppressing a decrease in the emission intensity of the SMS blue light-emitting phosphor due to heating when forming the phosphor layer of the laminate. Another object of the present invention is to provide an SMS blue light-emitting phosphor that has excellent heat resistance, that is, does not easily cause a decrease in emission intensity due to heating in an air atmosphere.

The present inventor has determined the diffraction intensity of the Sr ₃ MgSi ₂ O ₈ crystal phase obtained by X-ray diffraction using the Sr ₂ MgSi ₂ O ₇ crystal phase (Okermanite crystal phase) and the CuKα ray as the SMS blue light emitting phosphor. And the ratio B / (A + B) when the diffraction intensity of the Sr ₂ MgSi ₂ O ₇ crystal phase is B is in the range of 0.02 to 0.20, particularly in the range of 0.06 to 0.20. It has been found that the heat resistance of the SMS blue light emitting phosphor is improved by adding a small amount. Then, a coating layer of a dispersion liquid in which the SMS blue light-emitting phosphor containing a small amount of the Sr ₂ MgSi ₂ O ₇ crystal phase is dispersed is formed on the substrate, dried, and then heated, whereby SMS blue light emission is achieved. The present invention was completed by confirming that a laminate having a phosphor layer containing a phosphor could be produced.

Therefore, the present invention provides a coating layer of a dispersion liquid in which a phosphor layer forming material containing a blue light emitting phosphor or a phosphor layer forming material containing a blue light emitting phosphor and a phosphor emitting light other than blue is dispersed. A laminate comprising a substrate and a phosphor layer laminated on the substrate, which is formed on the substrate and then drying the coating layer and then heating at a temperature of 300 to 600 ° C. The blue light-emitting phosphor contains a Sr ₃ MgSi ₂ O ₈ crystal phase activated by Eu as a main component and a Sr ₂ MgSi ₂ O ₇ crystal phase as a subcomponent, and uses CuKα rays. The ratio B / (A + B) is 0.02 to 0, where A is the diffraction intensity of the Sr ₃ MgSi ₂ O ₈ crystal phase obtained by X-ray diffraction and B is the diffraction intensity of the Sr ₂ MgSi ₂ O ₇ crystal phase. In the laminate in the range of .20.

The present invention also provides a coating layer of a dispersion in which a phosphor layer-forming material containing a blue-emitting phosphor or a phosphor layer-forming material containing a blue-emitting phosphor and a phosphor that emits light other than blue is dispersed. A laminate comprising a substrate and a phosphor layer laminated on the substrate, which is produced by drying the coating layer and then heating the coating layer at a temperature of 300 to 600 ° C., and A light-emitting device including an excitation light source that emits excitation light for exciting the phosphor contained in the phosphor layer, wherein the blue light-emitting phosphor is activated by Eu with a Sr ₃ MgSi ₂ O ₈ crystal the phases as a main component and Sr ₂ comprises MgSi ₂ O ₇ crystal phase as an auxiliary component, and a diffraction intensity of Sr ₃ MgSi ₂ O ₈ crystal phase obtained by X-ray diffraction using a CuKα ray as a, Sr ₂ The diffraction intensity of the MgSi ₂ O ₇ crystal phase There is also a light emitting device having a ratio B / (A + B) in the range of 0.02 to 0.20 when B is assumed.

The present invention is further obtained by X-ray diffraction using Sr ₃ MgSi ₂ O ₈ crystal phase activated by Eu as a main component and Sr ₂ MgSi ₂ O ₇ crystal phase as a minor component, and using CuKα ray. The ratio B / (A + B) when the diffraction intensity of the Sr ₃ MgSi ₂ O ₈ crystal phase is A and the diffraction intensity of the Sr ₂ MgSi ₂ O ₇ crystal phase is B is in the range of 0.06 to 0.20. Some blue-emitting phosphors are also present.

The SMS blue light-emitting phosphor containing the Sr ₂ MgSi ₂ O ₇ crystal phase within the scope of the present invention has excellent heat resistance, as will be apparent from the data of Examples described later. Therefore, the laminate having the phosphor layer formed by heating the coating layer of the dispersion liquid in which the SMS blue-emitting phosphor is dispersed and the light emitting device including the laminate exhibit high emission intensity.

It is a perspective view of an example of an AC type plasma display panel according to the present invention. 1 is a cross-sectional view of an example of a cold cathode fluorescent lamp according to the present invention.

The SMS blue light-emitting phosphor used in the present invention contains a Sr ₃ MgSi ₂ O ₈ crystal phase activated by Eu as a main component and a small amount of Sr ₂ MgSi ₂ O ₇ crystal phase as a subcomponent.

The SMS blue light-emitting phosphor has a diffraction intensity of Sr ₃ MgSi ₂ O ₈ crystal phase activated by Eu and obtained by X-ray diffraction using CuKα ray as A, and diffraction of Sr ₂ MgSi ₂ O ₇ crystal phase. The ratio B / (A + B) when the strength is B is in the range of 0.02 to 0.20, preferably in the range of 0.06 to 0.20, particularly preferably in the range of 0.06 to 0.15. is there. The value of B / (A + B) indicates the amount of Sr ₂ MgSi ₂ O ₇ crystal phase contained in the SMS blue light emitting phosphor. The definition of the diffraction intensity A of the Sr ₃ MgSi ₂ O ₈ crystal phase activated by Eu and the diffraction intensity B of the Sr ₂ MgSi ₂ O ₇ crystal phase are described in the above-mentioned Patent Document 2 (Japanese Patent Laid-Open No. 2010-6850). Is the same. That is, the diffraction intensity A of the Sr ₃ MgSi ₂ O ₈ crystal phase activated by Eu is the peak diffraction intensity detected at about 32.7 ° at 2θ obtained by X-ray diffraction using CuKα rays. The diffraction intensity B of the Sr ₂ MgSi ₂ O ₇ crystal phase is the diffraction intensity of the peak detected at about 30.3 ° at 2θ.

  The Eu content of the SMS blue light emitting phosphor is preferably an amount that is in the range of 0.001 to 0.20 mol when the Mg content of the phosphor is 1 mol.

  Although there is no restriction | limiting in particular about the crystal lattice distortion of SMS blue light emission fluorescent substance, Generally it is 0.06 to 0.10% of range. The crystal lattice distortion is a value measured by the Le Bail method. A method for measuring the crystal lattice distortion of the SMS blue light-emitting phosphor by the Le Bail method is described in Patent Document 1 (Japanese Patent Laid-Open No. 2010-209206).

  In the SMS blue light emitting phosphor, for example, Sr source powder, Mg source powder, Si source powder and Eu source powder are mixed at a ratio to generate the SMS blue light emitting phosphor, and the obtained raw material powder mixture is reduced in a reducing atmosphere. It can manufacture by baking with. The mixing ratio of Sr source powder, Mg source powder, Si source powder and Eu source powder is generally 0.9 to 1.1 mol of Mg when the total amount of Sr and Eu in the powder mixture is 3 mol. This is the ratio at which Si is in the range of 1.9 to 2.1 mol.

The Sr source powder is preferably used by mixing strontium carbonate powder and strontium chloride powder. The blending amount of the strontium carbonate powder and the strontium chloride powder is preferably in the range of 1: 0.020 to 1: 0.13 in a molar ratio (SrCO ₃ : SrCl ₂ ), and is 1: 0.030 to 1: 0.13. A range is particularly preferred. If the blending amount of the strontium chloride powder is less than the above range, the content of the Sr ₂ MgSi ₂ O ₇ crystal phase in the SMS blue light emitting phosphor tends to be too small, and the blending amount of the strontium chloride powder is above When it exceeds the range, the content of the Sr ₂ MgSi ₂ O ₇ crystal phase tends to be excessive. However, the content of the Sr ₂ MgSi ₂ O ₇ crystal phase varies depending on conditions such as the size of the container and the firing temperature when firing the raw material powder mixture in a reducing atmosphere.

  It is preferable to use magnesium oxide powder as the Mg source powder. The Si source powder and Eu source powder may be oxide powders, and oxides are generated by heating hydroxides, halides, carbonates (including basic carbonates), nitrates, oxalates, and the like. It may be a powder of the compound. The raw material powders may be used alone or in combination of two or more. Each raw material powder preferably has a purity of 99% by mass or more.

  The raw material powder is preferably mixed by a wet mixing method. Examples of the mixing apparatus used when mixing the raw material powder by the wet mixing method include a rotating ball mill, a vibrating ball mill, a planetary mill, a paint shaker, a rocking mill, a rocking mixer, a bead mill, and a stirrer. Examples of the solvent used in the wet mixing method include water and lower alcohols such as ethanol, 1-propanol, and 2-propanol.

  The raw material powder mixture mixed by the wet mixing method is preferably fired after being formed into granules by spray drying. The firing of the raw material powder mixture in a reducing atmosphere may be performed in an atmosphere of a reducing gas containing 0.5 to 5.0% by volume of hydrogen and 99.5 to 95.0% by volume of an inert gas. preferable. Examples of inert gases include argon and nitrogen. The firing temperature is generally in the range of 900-1300 ° C. The firing time is generally in the range of 0.5 to 100 hours. Before firing in a reducing atmosphere, the powder mixture may be calcined at a temperature of 600 to 850 ° C. for 0.5 to 100 hours in an air atmosphere.

  The SMS blue light-emitting phosphor obtained as described above may be subjected to classification treatment, acid cleaning treatment with a mineral acid such as hydrochloric acid or nitric acid, and baking treatment as necessary.

  In the laminate having the phosphor layer of the present invention, a phosphor layer forming material containing a blue light emitting phosphor or a phosphor layer forming material containing a blue light emitting phosphor and a phosphor exhibiting light emission other than blue is dispersed. A coating layer of the dispersion is formed on the substrate, and then the coating layer is dried and then heated at a temperature of 300 to 600 ° C. In the laminate thus manufactured, the phosphor layer is usually in a state where the phosphors (powder) are bonded in a local region.

  As an example of a laminated body, the back plate of AC type PDP and the glass tube of CCFL can be mentioned. In the case of the back plate of the AC type PDP, the phosphor layer is manufactured from a phosphor layer forming material including a blue light emitting phosphor. In the case of a CCFL glass tube, the phosphor layer is manufactured from a phosphor layer forming material including a blue light emitting phosphor and a phosphor that emits light other than blue light. As the phosphor that emits light other than blue, a green light-emitting phosphor and a red light-emitting phosphor can be used.

  The solvent of the phosphor dispersion liquid is preferably an organic solvent. The organic solvent is not particularly limited, and alcohols, terpenes, ketones, ethers and esters can be used. Examples of the alcohol include monohydric alcohols such as ethanol, 1-propanol and 2-propanol, dihydric alcohols such as ethylene glycol and propylene glycol, and glycerin. Examples of terpenes include terpineol. Examples of ketones include acetone, methyl ethyl ketone, cyclohexanone and N-methyl-2-pyrrolidone. Examples of ethers include ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, dipropylene glycol monoalkyl ether and triethylene glycol monoalkyl ether. Examples of esters include ethyl acetate, butyl acetate, ethylene glycol monoalkyl ether acetate, diethylene glycol monoalkyl ether acetate and propylene glycol monoalkyl ether acetate.

  The phosphor dispersion liquid preferably contains an organic binder in order to increase the adhesion between the phosphors and the adhesion between the phosphor and the substrate. The organic binder is preferably one that volatilizes or decomposes when the coating layer is heated. Use organic binders such as cellulose resin, acrylic resin, ethylene-vinyl acetate copolymer resin, polyvinyl butyral, polyvinyl alcohol, propylene glycol, polyethylene oxide, urethane resin, melamine resin, and phenol resin as the binder. Can do. Examples of cellulosic resins include methylcellulose, ethylcellulose, propylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxymethylpropylcellulose and hydroxyethylpropylcellulose.

  As a method for forming the coating layer on the substrate, a dipping method, a screen printing method, an ink jet method, a spray method, a spin coater method, a meniscus method, or the like can be used. The coating layer is preferably dried and heated in an air atmosphere.

  The light emitting device of the present invention includes a laminate having a phosphor layer containing the above-described SMS blue light emitting phosphor and an excitation light source that emits excitation light for exciting the phosphor in the phosphor layer. Examples of the light emitting device include AC type PDP and CCFL.

  FIG. 1 is a perspective view of an example of an AC type PDP according to the present invention. In FIG. 1, the plasma display panel includes a front plate 20 and a back plate 30 which are arranged to face each other via a discharge space 10 filled with a discharge gas containing Xe gas. As the discharge gas filled in the discharge space 10, a mixed gas of Xe gas and Ne gas is usually used. The concentration of the Xe gas in the mixed gas is a concentration at which molecular beam emission occurs due to the discharge of the Xe gas, and is generally in the range of 10 to 30% by volume, preferably in the range of 15 to 25% by volume.

  The front plate 20 includes a transparent glass substrate 21, a discharge electrode 25 comprising two column electrodes 24a and 24b formed on the surface of the transparent glass substrate 21 on the back plate side, a dielectric layer 26 covering the discharge electrode, and a dielectric It consists of a dielectric protective layer 27 formed on the surface of the layer. The two column electrodes 24 a and 24 b constituting the discharge electrode 25 are each composed of a transparent electrode 22 and a bus electrode 23. The transparent electrode 22 is generally made of a conductive metal oxide film such as an ITO (indium tin oxide) film or a tin oxide film. The dielectric layer 26 is made of low-melting glass. The dielectric protective layer 27 is made of a magnesium oxide film.

  The back plate 30 includes a transparent glass substrate 31, an address electrode 32 formed on the surface of the transparent glass substrate 31 on the front plate side, a dielectric layer 33 that covers the address electrode 32, and a surface on the surface of the dielectric layer 33. The barrier ribs 34 are formed in stripes, and are composed of a blue light-emitting phosphor layer 35B, a green light-emitting phosphor layer 35G, and a red light-emitting phosphor layer 35R filled between the barrier ribs 34. The address electrode 32 is generally composed of a single phase metal film such as aluminum, copper and silver, or a laminated metal film such as chromium / copper / chromium. The dielectric layer 33 and the partition wall 34 are made of low melting point glass. The blue light emitting phosphor layer 35B is formed of the SMS blue light emitting phosphor.

  In the AC type PDP of FIG. 1, when a voltage is applied to the discharge electrode 25 of the front plate 20, the Xe gas in the discharge space 10 is discharged, and vacuum ultraviolet light having a wavelength of 146 nm and a wavelength of 172 nm is generated. By irradiating the blue light emitting phosphor layer 35B, the green light emitting phosphor layer 35G and the red light emitting phosphor layer 35R provided on the back plate 30 with this vacuum ultraviolet light as excitation light, When the phosphor is excited, visible light of the three primary colors of blue, green, and red is emitted, and an image is formed by a combination of these emitted lights.

  FIG. 2 is a cross-sectional view of an example CCFL according to the present invention. The CCFL is a light emitting device that uses Hg gas with an excitation light source under discharge and uses ultraviolet light including light emission with a wavelength of 254 nm as excitation light. In FIG. 2, CCFL is a glass tube 41 that is a glass member, a discharge gas filled in the internal space 42 of the glass tube 41, a phosphor layer 43 formed on the inner wall surface of the glass tube 41, and the longitudinal direction of the glass tube 41. It consists of a pair of electrodes 44a, 44b provided at both ends, and conductive lines 45a, 45b for electrically connecting the electrodes 44a, 44b and an external power source (not shown). As the discharge gas, a mixed gas of Hg gas and rare gas (for example, Ar gas) is generally used. The phosphor layer 43 includes a green light emitting phosphor and a red light emitting phosphor in addition to the SMS blue light emitting phosphor.

  In the CCFL of FIG. 2, when a high voltage is applied between the electrodes 44a and 44b, ultraviolet light having a wavelength of 254 nm is generated by the discharge of the Hg gas filled in the internal space. By irradiating the phosphor layer 43 provided in the glass tube 41 with this ultraviolet light as excitation light, each color phosphor in the phosphor layer 43 is excited, and visible light of blue, green and red is emitted. The white light is generated by the color mixture of these emitted lights.

[Example 1]
3150 g of strontium carbonate (SrCO ₃ ) powder (purity: 99.7% by mass, average particle diameter measured by laser diffraction scattering method: 0.9 μm), strontium chloride hexahydrate (SrCl ₂ .6H ₂ O) powder ( Purity: 99% by mass) 250 g, europium oxide (Eu ₂ O ₃ ) powder (purity: 99.9% by mass, average particle size measured by laser diffraction scattering method: 2.7 μm), 39.6 g, magnesium oxide ( MgO) powder (produced by vapor phase method, purity: 99.98% by mass, particle diameter converted from BET specific surface area: 0.2 μm) 302 g, silicon dioxide (SiO ₂ ) powder (purity: 99.9% by mass) %, Particle diameter converted from BET specific surface area: 0.01 μm) 901 g was weighed. The molar ratio of SrCO ₃ : SrCl ₂ .6H ₂ O: Eu ₂ O ₃ : MgO: SiO ₂ is 2.845: 0.125: 0.015: 1: 2.000. Each weighed powder was wet-mixed in water using a ball mill for 15 hours to obtain a powder mixture slurry. The obtained slurry was spray-dried with a spray dryer to obtain a powder mixture having an average particle size of 40 μm. The obtained dry powder was put in an alumina crucible (capacity: 950 cm ³ ), calcined at a temperature of 800 ° C. for 3 hours in an air atmosphere, then allowed to cool to room temperature, and then 2% by volume hydrogen−98% by volume. By firing at 1200 ° C. for 3 hours in an argon mixed gas atmosphere, an SMS blue light emitting phosphor was manufactured.

With respect to the obtained SMS blue light emitting phosphor, the ratio B / when the diffraction intensity of the Sr ₃ MgSi ₂ O ₈ crystal phase is A and the diffraction intensity of the Sr ₂ MgSi ₂ O ₇ crystal phase is B is determined by the following method. (A + B), emission intensity before and after heat treatment in the air atmosphere, and crystal lattice distortion were measured. Table 1 shows the measurement results.

[Measurement method of B / (A + B)]
The X-ray diffraction pattern of the SMS blue light emitting phosphor was measured under the following conditions, and the diffraction intensity of the diffraction peak detected in the range of 32.5 to 33.0 ° (near about 32.7 °) at 2θ. Sr ₃ MgSi ₂ O ₈ and the diffraction intensity a crystal phase, a diffraction intensity of a diffraction peak detected by 30.0 to 31.0 range ° (near about 30.3 °) at 2θ Sr ₂ MgSi ₂ O B / (A + B) was calculated as the diffraction intensity B of the ₇ crystal phase.

[Measurement conditions of X-ray diffraction pattern]
Measurement: Continuous measurement X-ray source: CuKα
Tube voltage: 40 kV
Tube current: 40 mA
Divergent slit width: 1/2 deg
Scattering slit width: 1/2 deg
Light receiving slit width: 0.30 mm
Scan mode: 2 deg / min Scan step: 0.02 deg

[Measurement method of emission intensity before and after heat treatment in air]
The emission intensity is measured by irradiating the SMS blue-emitting phosphor with ultraviolet light having a wavelength of 254 nm, measuring the emission spectrum, obtaining the maximum peak intensity within the wavelength range of 400 to 500 nm of the obtained emission spectrum, and emitting this. Strength. The light emission intensity is shown as a relative value with the light emission intensity before heat treatment of the SMS blue light emitting phosphor manufactured in Comparative Example 1 described later as 100.
The heat treatment was performed by heating the SMS blue light-emitting phosphor in an air atmosphere at a temperature of 540 ° C. for 30 minutes and then allowing to cool to room temperature.

[Measurement method of crystal lattice strain]
It was measured by the Le Bail method.

[Example 2]
An SMS blue light-emitting phosphor was produced in the same manner as in Example 1 except that the amount of strontium carbonate powder was 3067 g and the amount of strontium chloride hexahydrate was 400 g. The molar ratio of SrCO ₃ : SrCl ₂ .6H ₂ O: Eu ₂ O ₃ : MgO: SiO ₂ is 2.770: 0.200: 0.015: 1: 2.000. Table 1 shows the measurement results of B / (A + B), emission intensity before and after heat treatment in the air atmosphere, and crystal lattice distortion of the obtained SMS blue light-emitting phosphor.

[Comparative Example 1]
An SMS blue light emitting phosphor was produced in the same manner as in Example 1 except that the amount of strontium carbonate powder was 3233 g and the amount of strontium chloride hexahydrate was 100 g. The molar ratio of SrCO ₃ : SrCl ₂ .6H ₂ O: Eu ₂ O ₃ : MgO: SiO ₂ is 2.920: 0.050: 0.015: 1: 2.000. Table 1 shows the measurement results of B / (A + B), emission intensity before and after heat treatment in the air atmosphere, and crystal lattice distortion of the obtained SMS blue light-emitting phosphor.

Table 1
────────────────────────────────────────
Crystal lattice distortion after heat treatment before heat treatment
B / (A + B) Emission intensity Emission intensity (%)
────────────────────────────────────────
Example 1 0.079 87 77 0.075
Example 2 0.126 86 77 0.071
────────────────────────────────────────
Comparative Example 1 0.001 or less 100 65 0.080
────────────────────────────────────────

As is clear from the results in Table 1, the ratio B / (A + B) when the diffraction intensity of the Sr ₃ MgSi ₂ O ₈ crystal phase is A and the diffraction intensity of the Sr ₂ MgSi ₂ O ₇ crystal phase is B is as the scope of the present invention, Sr ₂ MgSi ₂ O ₇ phase SMS blue phosphor containing less decrease in emission intensity due to heat treatment, SMS blue emission free of Sr ₂ MgSi ₂ O ₇ phase substantially Compared with the phosphor, the emission intensity before the heat treatment shows a low value, but the emission intensity after the heat treatment shows a high value.

[Example 3]
To 65.5 g of diethylene glycol monobutyl ether acetate, 30 g of the SMS blue light emitting phosphor produced in Example 1 and 4.5 g of ethylcellulose having a mass average molecular weight of about 200,000 were added and stirred to obtain a phosphor dispersion. This phosphor dispersion was applied to a glass substrate by a dip method, and the coating layer was dried and then heated at a temperature of 540 ° C. for 30 minutes to produce a laminate having an SMS blue light emitting phosphor layer. Blue light was emitted by irradiating the SMS blue light emitting phosphor layer of this laminate with ultraviolet light having a wavelength of 254 nm.

DESCRIPTION OF SYMBOLS 10 Discharge space 20 Front plate 21 Transparent glass substrate 22 Transparent electrode 23 Bus electrode 24a, 24b Column electrode 25 Discharge electrode 26 Dielectric layer 27 Dielectric protective layer 30 Back plate 31 Transparent glass substrate 32 Address electrode 33 Dielectric layer 34 Partition 35B Blue light emitting phosphor layer 35G Green light emitting phosphor layer 35R Red light emitting phosphor layer 41 Glass tube 42 Internal space 43 Phosphor layer 44a, 44b Electrode 45a, 45b Conductive wire

Claims (6)

A coating layer of a dispersion liquid in which a phosphor layer forming material containing a blue emitting phosphor or a phosphor layer forming material containing a blue emitting phosphor and a phosphor emitting light other than blue is dispersed is formed on a substrate. Then, the coated layer is dried and then heated at a temperature of 300 to 600 ° C., and is a laminate comprising a substrate and a phosphor layer laminated on the substrate, the blue light emitting The phosphor has a Sr ₃ MgSi ₂ O ₈ crystal phase activated with Eu as a main component and a Sr ₂ MgSi ₂ O ₇ crystal phase as a minor component, and is obtained by X-ray diffraction using CuKα rays. The ratio B / (A + B) is in the range of 0.02 to 0.20, where A is the diffraction intensity of the Sr ₃ MgSi ₂ O ₈ crystal phase and B is the diffraction intensity of the Sr ₂ MgSi ₂ O ₇ crystal phase. Laminated body.   The laminate according to claim 1, wherein the ratio B / (A + B) is in the range of 0.06 to 0.20. A coating layer of a dispersion liquid in which a phosphor layer forming material containing a blue emitting phosphor or a phosphor layer forming material containing a blue emitting phosphor and a phosphor emitting light other than blue is dispersed is formed on a substrate. Then, after drying the coating layer, a laminate comprising a substrate and a phosphor layer laminated on the substrate, which is produced by heating at a temperature of 300 to 600 ° C., and the phosphor layer A light-emitting device including an excitation light source that emits excitation light for exciting the included phosphor, wherein the blue light-emitting phosphor has a Sr ₃ MgSi ₂ O ₈ crystal phase activated by Eu as a main component. Sr ₂ MgSi ₂ O ₇ crystal phase as an accessory component, and the diffraction intensity of the Sr ₃ MgSi ₂ O ₈ crystal phase obtained by X-ray diffraction using CuKα rays is A, and Sr ₂ MgSi ₂ O ₇ crystal When the diffraction intensity of the phase is B A light emitting device having a ratio B / (A + B) in the range of 0.02 to 0.20.   The light-emitting device according to claim 3, wherein the ratio B / (A + B) is in the range of 0.06 to 0.20.   4. The light emitting device according to claim 3, wherein the light emitting device is an AC plasma display panel or a cold cathode fluorescent lamp. A main component Sr ₃ MgSi ₂ O ₈ crystal phase which is activated by Eu, and Sr ₂ MgSi ₂ O ₇ comprises crystalline phase as an auxiliary component, and Sr obtained by X-ray diffraction using a CuKα ray ₃ MgSi ₂ A blue light emitting phosphor having a ratio B / (A + B) in the range of 0.06 to 0.20, where A is the diffraction intensity of the O ₈ crystal phase and A is the diffraction intensity of the Sr ₂ MgSi ₂ O ₇ crystal phase. .

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