JP5471021B2 - Phosphor and phosphor manufacturing method, phosphor-containing composition, light emitting device, illumination device, and image display device - Google Patents

Description

The present invention relates to a phosphor having a crystal phase represented by (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu having high durability, a method for producing the phosphor, the phosphor-containing composition, The present invention relates to a light emitting device, an image display device, and a lighting device used. Specifically, the phosphor represented by (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu having specific physical properties, a method for producing the phosphor, the phosphor-containing composition, and a light emitting device using the phosphor, The present invention relates to an image display device and an illumination device.

In recent years, semiconductor light emitting devices in which a light source such as a light emitting diode (hereinafter abbreviated as “LED”) and a phosphor are combined have been put into practical use, and the development of each color phosphor used in these devices has also been made. Various things are done.
Among them, Patent Document 1 describes a red light-emitting nitride phosphor represented by (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu.

Patent Documents 2 to 5 describe that a coating layer of a specific compound is formed on the surface in order to suppress deterioration of the nitride phosphor.
In addition, Patent Document 6 describes reheating at a temperature lower than the firing temperature in order to improve the durability of the nitride phosphor.

Special table 2003-515655 gazette JP 2004-161807 A JP 2006-282809 A JP 2006-269938 A JP 2007-103918 A Publication pamphlet of WO2009 / 017206

As a light emitter used in an illuminating device, an image display device or the like, it is required to withstand long-time use. However, in the method using the coating agent as described in Patent Documents 2 to 5, it is difficult to coat the phosphor surface uniformly, and from the viewpoint of industrial production, the durability is improved more easily and inexpensively. There is always a need for the emergence of methods.
The present invention was devised in view of the above problems, and in a phosphor having a crystal phase represented by (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu, a phosphor having higher durability It is a first object of the present invention to further provide a method for producing the phosphor, and a phosphor-containing composition, a light emitting device, an illumination device, and an image display device using the phosphor. .

As a result of intensive studies to solve the above-described problems, the present inventors have found that (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu phosphors exhibiting physical property values have high durability. It was.
In addition, based on the conventional knowledge, as also in Comparative Example 1 of Patent Document 4, when the heat treatment is performed at a low temperature of about 300 ° C. in an oxidizing atmosphere, the nitride phosphor is supposed to deteriorate. In the case of (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu phosphor, among the conditions described in Patent Document 6, it is more durable by performing heat treatment within a certain temperature range. The present inventors have found that an excellent phosphor can be obtained and completed the present invention.

That is, the gist of the present invention is the following (1) to (13).
(1) A phosphor containing a crystal phase represented by the formula [I], the ratio of the amount of oxygen atoms to the amount of nitrogen atoms detected when the surface of the phosphor particles is analyzed by X-ray photoelectron spectroscopy (XPS) A phosphor having an (O / N ratio) of 2.0 or more.
M _2-2x Eu _2x Si ₅ N ₈ [I]
(In the formula [I], M represents an alkaline earth metal element containing at least Sr,
x represents a numerical value in a range represented by 0 <x <1. )
(2) Under the conditions of temperature 25 ° C. and humidity 10% to 70%, light with a wavelength of 254 nm is irradiated until the 1/1000 afterglow time of the phosphor becomes constant, time constant 0.01 seconds, measurement interval The phosphor as described in (1) above, wherein the afterglow time of 1/1000 when the afterglow characteristic is measured under a condition of 0.005 seconds is within 4.1 seconds.
(3) The spin density corresponding to the absorption of g = 2.00 ± 0.02 measured by electron spin resonance spectrum under the condition of 25 ° C. is 4.5 × 10 ⁻⁹ mol / g or less. The phosphor according to (1) or (2), characterized in that it is characterized.
(4) A method for producing a phosphor containing a crystal phase represented by the formula [I] by firing a phosphor material, wherein the fired product is heated at a temperature of 350 ° C. to 600 ° C. after the firing step. A method for producing a phosphor, comprising a step of re-firing.

M _2-2x Eu _2x Si ₅ N ₈ [I]
(In the formula [I], M represents an alkaline earth metal element containing at least Sr,
x represents a numerical value in a range represented by 0 <x <1. )
(5) The production method as described in (4) above, wherein the firing atmosphere at the time of re-firing is an oxygen-containing atmosphere.
(6) The method according to (4) or (5) above, which comprises a step of washing the fired product with an acidic liquid medium after the firing step and before the re-firing step.
(7) A phosphor-containing composition comprising the phosphor according to any one of (1) to (3) above and a liquid medium.
(8) A light emitting device having a first light emitter and a second light emitter that emits visible light by irradiation of light from the first light emitter, and the second light emitter is the above ( A light-emitting device comprising a first phosphor containing one or more of the phosphors according to any one of 1) to (3).
(9) In the above (8), the second phosphor includes a second phosphor including one or more phosphors having emission peak wavelengths different from those of the first phosphor. The light-emitting device of description.
(10) The first phosphor has an emission peak in a wavelength range of 420 nm or more and 500 nm or less, and at least one phosphor having an emission peak in a wavelength range of 500 nm or more and less than 550 nm as the second phosphor. The light-emitting device according to (9), wherein the light-emitting device is used.
(11) The first light emitter has a light emission peak in a wavelength range of 300 nm to 420 nm, and the second light emitter has a light emission peak in a wavelength range of 420 nm to less than 500 nm as the second phosphor. The light-emitting device according to (9), wherein the light-emitting device comprises at least one phosphor having a light emission peak and at least one phosphor having a light emission peak in a wavelength range of 500 nm or more and less than 550 nm.
(12) An illumination device comprising the light-emitting device according to any one of (8) to (11).
(13) An image display device comprising the light-emitting device according to any one of (8) to (11).

  According to the present invention, a nitride phosphor having high durability can be obtained by a simple and inexpensive method, and a phosphor-containing composition, a light emitting device, a lighting device, and an image display device using the phosphor can be realized. be able to.

It is a typical perspective view which shows the positional relationship of an excitation light source (1st light emission body) and a fluorescent substance containing part (2nd light emission body) in an example of the light-emitting device of this invention. 2 (a) and 2 (b) are schematic cross sections showing an embodiment of a light emitting device having an excitation light source (first light emitter) and a phosphor-containing portion (second light emitter). FIG. It is sectional drawing which shows typically one Embodiment of the illuminating device of this invention. It is a figure which shows the afterglow characteristic of each fluorescent substance of the Example and comparative example of this invention. It is a figure which shows the durability test result (CIEx maintenance factor) of the light-emitting device using each fluorescent substance of the comparative examples 1 and 2 of this invention, and Example 1. FIG. It is a figure which shows the durability test result (CIEy maintenance factor) of the light-emitting device using each fluorescent substance of the comparative examples 1 and 2 of this invention, and Example 1. FIG. It is a figure which shows the durability test result (CIEx maintenance factor) of the light-emitting device using each fluorescent substance of Example 2 and 3 of this invention. It is a figure which shows the durability test result (CIEy maintenance factor) of the light-emitting device using each fluorescent substance of Example 2 and 3 of this invention.

Hereinafter, the present invention will be described in detail with reference to embodiments, examples, etc., but the present invention is not limited to the following embodiments, examples, etc., and may be arbitrarily changed without departing from the gist thereof. Can be implemented.
The relationship between the color name and the chromaticity coordinates in this specification is all based on the JIS standard (JIS Z8110 and Z8701).

In the composition formula of the phosphors in this specification, each composition formula is delimited by a punctuation mark (,). In addition, when a plurality of elements are listed by separating them with commas (,), it indicates that one or more of the listed elements may be contained in any combination and composition. For example, the composition formula “(Ca, Sr, Ba) Al ₂ O ₄ : Eu” has “CaAl ₂ O ₄ : Eu”, “SrAl ₂ O ₄ : Eu”, and “BaAl ₂ O ₄ : Eu”. “Ca _1−x Sr _x Al ₂ O ₄ : Eu”, “Sr _1−x Ba _x Al ₂ O ₄ : Eu”, “Ca _1−x Ba _x Al ₂ O ₄ : Eu”, _{"Ca 1-x-y Sr x} Ba y Al 2 O 4: Eu " and all assumed to generically indicated (in the above formula, 0 <x <1,0 <y <1,0 <X + y <1).

1. Phosphor [1-1] Composition The phosphor of the present invention has a crystal phase represented by the formula [I].
M _2-2x Eu _2x Si ₅ N ₈ [I]
In the above formula [I], M represents an alkaline earth metal element such as Mg, Ca, Sr and Ba, and contains at least Sr. Among these, it is preferably selected from the group consisting of Ba, Ca and Sr, and contains at least Sr.

Further, containing at least Sr usually means that the molar amount of Sr with respect to the total M element amount is 10% or more, preferably 20% or more, more preferably 50% or more, and still more preferably 80%. Above, especially preferably 90% or more.
Further, the molar amounts of Ba and Ca with respect to the total amount of M element are each independently a value of 0% or more and 80% or less.

In the above formula [I], x relates to the amount of the activating element and is a numerical value in a range represented by 0 <x <1.
Among these, Preferably it is 0.001 or more, More preferably, it is 0.005 or more, More preferably, it is 0.010 or more, Most preferably, it is 0.015 or more, Preferably it is 0.200 or less, More preferably, it is 0.150. Hereinafter, the value is more preferably 0.100 or less, and particularly preferably 0.050 or less.

[1-2] Nitrogen atoms and oxygen atomic weight on the particle surface of the phosphor The phosphor of the present invention has an oxygen atomic weight relative to the nitrogen atom amount detected when the phosphor particle surface is analyzed by X-ray photoelectron spectroscopy (XPS). Ratio (O / N ratio) is 2.0 or more, preferably 2.4 or more.
The phosphor of the present invention having such characteristics exhibits durability superior to that of the prior art.

Here, the O / N ratio (molar ratio) of the phosphor particle surface by XPS analysis can be obtained as follows.
A sample (phosphor) is measured under the following measurement conditions using a Quantum 2000 manufactured by PHI.
-X-ray source: Monochromatic Al-Kα, output 16 kV-34 W (X-ray generation area 170 μmφ)
・ Charge neutralization: Electron gun 2μA, combined use with ion gun
・ Spectroscopic system: Path energy
187.85 eV = wide spectrum
58.7 eV = Narrow spectrum [C1s, Eu3d3 / 2]
29.35 eV = Narrow spectrum [N1s, O1s, Si2p, Sr3d] Measurement area: 300 μmφ
・ Extraction angle: 45 ° (from the surface)
The principle by which the atomic ratio of the phosphor particle surface can be obtained by the XPS analysis as described above is as follows.

  When a solid surface is irradiated with X-rays in a vacuum, electrons (photoelectrons) are generated from surface atoms. Since this photoelectron has an energy value specific to the element, the composition of the solid surface can be examined by measuring the energy distribution. Since photoelectrons generated deep from the surface are absorbed before they emerge on the surface, the depth that can be analyzed by this method is on average several tens of atomic layers from the surface (from 3 nm to 5 nm deep from the surface). ) Area. In addition, in this analysis method, the binding energy is slightly different depending on the type of compound, and therefore information on chemical bonds of each element constituting the compound can be obtained by examining the energy distribution of photoelectrons.

In addition to XPS, for example, the atomic ratio of the phosphor particle surface and the distribution in the depth direction can be obtained by Auger electron spectroscopy (AES). In addition, state analysis can be performed by measuring the Auger electron spectrum with high resolution.
Nitrogen may be present on the surface, but the surface generated by natural oxidation when a phosphor fired by a conventionally known production method (for example, the phosphor obtained in Comparative Example 1 described later) is exposed to the atmosphere. It is characterized by less nitrogen than (natural oxide film). Further, the surface layer tends to contain more oxygen and more alkaline earth metal than the natural oxide film.

From the above analysis results, it is considered that at least a part of the alkaline earth metal element exists as a complex oxide or oxo acid salt in the surface layer.
Hereinafter, this will be described by taking as an example the case where the composition of the _host crystal of the phosphor is Sr ₂ Si ₅ N ₈ or Sr _2-2x Ba _2x Si ₅ N _8. The composition of the phosphor of the present invention is as follows. However, it is not limited to these compositions.

(Guess 1)
Non-Patent Document 2 (Frank L. Riley, J. Am. Ceram. Soc., 83 [2] 245-65 (2000)), i) When silicon nitride is heated at 1000 ° C. or higher in the atmosphere, SiO ₂ is formed on the surface. Ii) the presence of Si ₂ N ₂ O between the oxide film and silicon nitride, and iii) the composition continuously from the oxide film SiO ₂ toward Si ₃ N _4. Has been reported to have changed.
If heat treatment is performed at a high temperature in an oxidizing atmosphere, it is presumed that a surface film made of a composite oxide containing Sr is easily formed on the surface of Sr ₂ Si ₅ N ₈ as in the case of silicon nitride. The composite oxide containing Sr easily forms a crystal phase, and thus the formed film has a dense structure as compared with an amorphous (glass) phase oxide film made of SiO ₂ .

(Guess 2)
Furthermore, as described above, the phosphor (Sr ₂ Si ₅ N ₈ or Sr _2-2x Ba _2x Si ₅ N ₈ etc.) and the surface oxide film have already been reported in the patent document (WO2005 / 116163 A1). Deficient oxynitride ((M, □) _{2 in which} Sr and Ba at the alkaline earth metal site escape from the crystal structure due to oxidation, such as (Ba, □) ₂ Si ₅ (N, O) ₈ If Si ₅ (N, O) ₈ M = Sr, Ba, etc.) is formed, a denser crystal phase is inserted as a layer between the surface oxide film and the phosphor surface, and diffusion of oxygen, water vapor, etc. On the other hand, there is a possibility that the gas barrier property is improved as an effective barrier. The properties (thickness, etc.) of this (M, □) ₂ Si ₅ (N, O) ₈ layer vary depending on the alkaline earth metal element content and the type of alkaline earth metal in the phosphor. ) Moisture resistance may vary depending on the nature of the ₂ Si ₅ (N, O) ₈ layer.

Even if the (M, □) ₂ Si ₅ (N, O) ₈ layer does not exist, if the composition changes continuously between the surface oxide film and the phosphor surface, Close parts show properties closer to (M, □) ₂ Si ₅ (N, O) ₈ than SiO ₂ , thereby improving adhesion to the phosphor and serving as a diffusion barrier for water molecules, etc. There is a possibility of improvement.
In the above composition formula, □ indicates a lattice defect (a defect of a cation element).

(Guess 3)
Known knowledge such as Non-Patent Document 2 based on (Estimation 1) and (Estimation 2) relates to an oxide layer at a high temperature of 1000 ° C. or higher. Since the surface layer in the present invention is formed at a relatively low temperature (for example, around 350 to 600 ° C.), its composition and properties may be different.

However, even if it is assumed that the (Ba, □) ₂ Si ₅ (N, O) ₈ layer as described in (Estimation 1) and (Estimation 2) is not formed by the refiring step of the present invention, the refiring step As a result, a composite oxide containing an alkaline earth metal is formed, and the presence of the surface layer containing this oxide may improve the durability as compared with a naturally formed oxide film. For example, SrO quickly changes to Sr (OH) ₂ in the atmosphere, but Sr ₂ SiO _4, which is a composite oxide, tends to be harder to hydrolyze than SrO. In addition, (guess 1) to (
Inference 3) may occur independently, or two or more may occur in combination.

  In addition, although it is preferable to perform the below-mentioned rebaking process as a method of producing | generating such a surface layer, there will be no restriction | limiting in particular as long as the reconstruction of a surface layer is accompanied. For example, instead of or in addition to the re-baking step described later, heating may be performed in an atmosphere containing a chalcogen such as oxygen, a halogen such as fluorine, a water vapor, or a nitrogen oxide such as NO. . In addition, as a method for generating such a surface layer, a liquid phase reaction may be used instead of a gas phase reaction as in the re-baking step described later. In this case, it may be oxidized with hydrogen peroxide or nitric acid instead of oxygen or the like.

[1-3] Durability The phosphor of the present invention relates to light emission when a semiconductor light emitting device is produced using the phosphor, specifically, chromaticity coordinate values (CIEx, CIEy) based on JIS Z8701, The amount of change of the chromaticity coordinate value with respect to the light emission time of the semiconductor light emitting device is smaller than that of the conventional phosphor.

Specifically, a semiconductor light-emitting device using the phosphor of the present invention is prepared, driven at 20 mA, and CIE chromaticity coordinate values (CIEx, CIEy) are measured. On the other hand, CIE chromaticity coordinate values (CIEx, CIEy) after driving for 1000 hours at 20 mA under conditions of high temperature and high humidity of temperature 85 ° C. and humidity 85% are CIE chromaticity coordinate values (CIEx, CIEy) immediately after driving. ) Is 100, CIEx is 75 or more, preferably 80 or more, more preferably 85 or more, still more preferably 90 or more, and CIEy is 65 or more, preferably 70 or more, more preferably 75 or more. More preferably 80 or more.
Therefore, it is preferable to use such a highly durable phosphor because the color shift of the light emitting device is reduced.

[1-4] Afterglow characteristics A phosphor having a crystal phase represented by the above formula [I] usually emits both fluorescence and phosphorescence. Compared with fluorescence, phosphorescence has the property of being emitted over a relatively long time after the point where irradiation of excitation light to the phosphor is stopped. The phenomenon in which light is emitted from the phosphor even after the point of time when the excitation light irradiation is stopped is called afterglow.

The short time when the afterglow is emitted, that is, the short afterglow time, specifically means that the afterglow time is 1/1000 under the conditions of a temperature of 25 ° C. and a humidity of 10% to 70%. Is sufficiently irradiated with light (excitation light) at a wavelength of 254 nm until the time constant becomes 1/1000, and afterglow characteristics are measured under the conditions of a time constant of 0.01 seconds and a measurement interval of 0.005 seconds. The light time is usually 4.1 seconds or less, preferably 2.4 seconds or less, more preferably 1.5 seconds or less. A phosphor having a short 1/1000 afterglow time has few lattice defects in the crystal phase and is a single phase or a crystal phase very close to a single phase (that is, a crystal phase in which all or most of the crystal phases of the phosphor are the same). Crystal phase state). By having such a crystal phase, the phosphor can exhibit high durability. On the other hand, as the lower limit of the 1/1000 persistence time, phosphorescence is usually caused by lattice defects, and it is preferable that the phosphorescence is short, but it is usually 1 × 10 ⁻⁶ seconds or more, and more ideally 1 × 10 ⁻⁹ seconds or more.

Here, the 1/1000 afterglow time is 1/1000 of the intensity of light (emission) emitted from the phosphor from the time when the irradiation of the excitation light is stopped, and the intensity of the light emitted when the irradiation of the excitation light is stopped. This is the time required for the time to drop.
In general, the afterglow time tends to increase as the irradiation intensity of the excitation light is increased and the irradiation time is increased. However, when the irradiation intensity and irradiation time of the excitation light exceed a certain threshold value, the afterglow time does not increase and the afterglow time becomes constant even if the irradiation intensity and irradiation time of the excitation light are further increased and increased. In the measurement of 1/1000 afterglow time according to the present invention, the above property is utilized, and even if the irradiation intensity of the excitation light is increased or the irradiation time is increased, the 1/1000 afterglow time is increased. The 1/1000 afterglow time is measured after the excitation light is sufficiently irradiated until it becomes constant.

The means for shortening the 1/1000 afterglow time as described above is not particularly limited as long as it is a method for reducing lattice defects of the phosphor crystal. For example, phosphor raw material (also referred to as a raw material compound) And improving the crystallinity by optimizing the mixing ratio and firing conditions of the phosphor raw materials and providing a reheating step as described later. However,
The means for shortening the 1/1000 afterglow time is not limited to the means exemplified here, and the above effect can be obtained even when the 1/1000 afterglow time of the phosphor is shortened by other means. Is possible.

[1-5] Electron Spin Density The phosphor of the present invention has a spin density of 4.5 corresponding to absorption of g = 2.00 ± 0.02 measured by an electron spin resonance spectrum at 25 ° C. × 10 ⁻⁹ mol / g or less. Of these, the spin density is preferably 4.0 × 10 ⁻⁹ mol / g or less, and more preferably 3.5 × 10 ⁻⁹ mol / g or less. The electron spin density is preferably as small as possible, but is usually greater than zero.

The electron spin resonance (ESR) method is a phenomenon in which the energy level of an unpaired electron is split in the magnetic field by the Zeeman effect, and the unpaired electron absorbs an electromagnetic wave having the same energy as the split width of the energy level. Information on the absorption intensity of the electron spin resonance spectrum, the number of unpaired electrons existing from the absorption wavelength (spin density), and the state thereof can be obtained.
Here, the above-mentioned spin density can be obtained by dividing the number of spins measured by ESR by the sample mass used for the measurement.
Here, the spin density by the electron spin resonance (ESR) method can be measured as follows.

A 300 mg sample (phosphor) is measured using the FA300 manufactured by JEOL at room temperature in the air under the following measurement conditions.
High magnetic field range / central magnetic field: 250 mT
-Sweep magnetic field width: ± 250mT
Magnetic field modulation: 100 kHz
・ Response: 0.1 sec
・ Magnetic field sweep time: 15 min
・ Microwave output: 0.1 mW
Narrow magnetic field range, central magnetic field: 323mT
・ Sweep magnetic field width: ± 10mT
Magnetic field modulation: 100 kHz
・ Response: 0.1 sec
・ Magnetic field sweep time: 2 min
・ Microwave output: 0.1 mW
The sample is filled in a quartz sample tube having a diameter of 5 mm. In addition, as a standard sample for radical determination, 2,2,6,6-tetramethylpiperidine-1-oxyl dispersed in a polystyrene matrix is used, and Mn ²⁺ is used for correction of g value and magnetic field width. To do.

[1-6] Other characteristics <Emission spectrum>
The phosphor of the present invention preferably has the following characteristics in the emission spectrum measured when excited with light having a wavelength of 455 nm.
Specifically, the emission peak wavelength is usually 570 nm or more, preferably 590 nm or more, more preferably 610 nm or more, and usually 700 nm or less, preferably 650 nm or less, more preferably 630 nm or less.

The half-value width of the emission peak is usually 60 nm or more, preferably 65 nm or more, more preferably 70 nm or more, and is usually 125 nm or less, preferably 120 nm or less, more preferably 115 nm or less.
In addition, as a measuring method of this emission spectrum, the method described in the item of the below-mentioned Example is mentioned.

<Particle size>
The phosphor of the present invention has a weight median diameter D ₅₀ of usually 0.01 μm or more, preferably 1 μm or more, more preferably 5 μm or more, further preferably 10 μm or more, and usually 100 μm or less, preferably 30 μm or less. More preferably, it is in the range of 20 μm or less. When the weight-average median diameter D ₅₀ is too small, and the luminance decreases tends to phosphor particles aggregate. On the other hand, when the weight-average median diameter D ₅₀ is too large, there is a tendency for blockage, such as uneven coating or a dispenser.

The above-mentioned weight-average median diameter D _50, is a value obtained by the frequency particle size distribution curve. The frequency reference particle size distribution curve is obtained by measuring the particle size distribution by a laser diffraction / scattering method. Specifically, the phosphor was dispersed in an aqueous solution containing a dispersant, and measured by a laser diffraction particle size distribution measuring device (Horiba LA-300) in a particle size range of 0.1 μm to 600 μm. Is. In this frequency particle size distribution curve, the accumulated value is the particle size value when the 50% and weight-average median diameter D _50.

[1-7] Use of phosphor The phosphor of the present invention can be used for any application using a phosphor. In addition, the phosphor of the present invention can be used alone, but two or more of the phosphors of the present invention can be used together, or the phosphor of the present invention and other phosphors It is also possible to use as a phosphor mixture of any combination.

  In addition, the phosphor of the present invention can be suitably used for various light-emitting devices (hereinafter referred to as “light-emitting device of the present invention”) taking advantage of the characteristic that it can be excited by blue light. Since the phosphor of the present invention is usually a red light-emitting phosphor, for example, when an excitation light source that emits blue light is combined with the phosphor of the present invention, a purple to pink light-emitting device can be manufactured. . In addition, the phosphor of the present invention is combined with an excitation light source that emits blue light and a phosphor that emits green light, or an excitation light source that emits near-ultraviolet light, a phosphor that emits blue light, and a fluorescence that emits green light. If the body is combined, the phosphor of the present invention emits red light when excited by blue light from an excitation light source that emits blue light or a phosphor that emits blue light, and thus a white light emitting device is manufactured. be able to.

  The emission color of the light-emitting device is not limited to white, and by appropriately selecting the combination and content of phosphors, a light-emitting device that emits light in any color such as light bulb color (warm white) or pastel color is manufactured. can do. The light-emitting device thus obtained can be used as a light-emitting portion (particularly a liquid crystal backlight) or an illumination device of an image display device.

2. Method for Producing Phosphor The phosphor of the present invention is a phosphor raw material powder and / or a fired product obtained by mixing and firing them (in the present specification, these are collectively referred to as a phosphor precursor). Although it manufactures according to the well-known method of baking, it is obtained through the rebaking process of this baked product in the specific temperature range of 350 degreeC or more and 600 degrees C or less after this baking process.
Hereinafter, the phosphor raw material, the phosphor manufacturing method, and the like will be specifically described.

[2-1. Phosphor raw material]
Examples of phosphor raw materials used in the production of the phosphor of the present invention (that is, M element raw materials (hereinafter sometimes referred to as M sources), Eu raw materials, and Si raw materials) include these elements. Among them, preferred examples include metals, alloys, imide compounds, amide compounds, oxynitrides, nitrides, oxides, hydroxides, carbonates, nitrates, sulfates, oxalates. , Carboxylates, halides and the like. The phosphor material may be appropriately selected from these in consideration of the reactivity to the composite oxynitride and the low generation amount of NO _x , SO _x, etc. during firing.

Further, the impurities contained in the phosphor raw material are not particularly limited as long as the performance of the phosphor is not affected. However, with respect to Fe, Co, Cr and Ni, those usually used are 1000 ppm or less, preferably 100 ppm or less, more preferably 50 ppm or less, still more preferably 10 ppm or less, and particularly preferably 1 ppm or less.
The weight median diameter of each phosphor material is usually 0.1 μm or more, preferably 0.5 μm or more, and usually 30 μm or less, preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 3 μm or less. Is used. For this reason, depending on the type of the phosphor material, pulverization may be performed in advance by a dry pulverizer such as a jet mill. As a result, each phosphor raw material can be uniformly dispersed in the raw material mixture, and the solid phase reactivity of the raw material mixture can be increased by increasing the surface area of the phosphor raw material, thereby suppressing the generation of impurity phases. It becomes. In particular, in the case of a nitride material, it is preferable to use a material having a smaller particle size than other phosphor materials from the viewpoint of reactivity.

[Description of M source]
Among the M sources, specific examples of Mg raw materials (Mg sources) include MgO, Mg (OH) ₂ , basic magnesium carbonate (mMgCO ₃ .Mg (OH) ₂ .nH ₂ O), Mg (NO ₃ ). _{2 · 6H 2 O, MgSO 4} , Mg (C 2 O 4) · 2H 2 O, Mg (OCOCH 3) 2 · 4H 2 O, MgCl 2, MgF 2, Mg 3 N 2, MgNH, Mg (NH 2) ₂ etc. are mentioned. Of these, MgO and basic magnesium carbonate are preferred.

Among the M sources, specific examples of the Ca raw material (Ca source) include CaO, Ca (OH) ₂ , CaCO ₃ , Ca (NO ₃ ) ₂ .4H ₂ O, CaSO ₄ .2H ₂ O, and Ca (C ₂ O ₄ ) · H ₂ O, Ca (OCOCH ₃ ) ₂ .H ₂ O, CaCl ₂ , CaF ₂ , Ca ₃ N ₂ , CaNH, Ca (NH ₂ ) _{2 and the} like. Of these, CaCO ₃ , anhydrous CaCl _{2 and the} like are preferable.
Among the M sources, specific examples of Sr raw materials (Sr sources) include SrO, Sr (OH) ₂ .8H ₂ O, SrCO ₃ , Sr (NO ₃ ) ₂ , SrSO ₄ , Sr (C ₂ O ₄ ). _{· H 2 O, Sr (OCOCH} 3) 2 · 0.5H 2 O, SrCl 2, SrF 2, Sr 2 N, SrNH, Sr (NH 2) 2 and the like. Among these, SrCO ₃ is preferable. This is because the stability in the air is good, it is easily decomposed by heating, it is difficult for undesired elements to remain, and it is easy to obtain high-purity raw materials.

Specific examples of the Ba source include BaO, Ba (OH) ₂ .8H ₂ O, BaCO ₃ , Ba (NO ₃ ) ₂ , BaSO ₄ , Ba (C ₂ O ₄ ), Ba (OCOCH ₃ ) ₂ , BaCl _2. , BaF ₂ , Ba ₂ N, BaNH, Ba (NH ₂ ) _{2 and the} like. Of these, carbonates, oxides, and the like can be preferably used, but carbonates are more preferable from the viewpoint of handling because oxides easily react with moisture in the air. Of these, BaCO ₃ is preferable. This is because the stability in the air is good, and it is easily decomposed by heating, so that undesired elements hardly remain and it is easy to obtain high-purity raw materials.
Here, when carbonate is used as the M source, it is preferable that the carbonate is preliminarily calcined and used as the raw material.

[Description of Eu source]
Specific examples of Eu raw materials (Eu sources) include Eu ₂ O ₃ , Eu ₂ (SO ₄ ) ₃ , Eu ₂ (C ₂ O ₄ ) ₃ · 10H ₂ O, EuCl ₂ , EuCl ₃ , EuF ₂ , EuF ₃ , Eu (NO
_{3) 3 · 6H 2 O,} EuN, EuNH, Eu (NH 2) 2 and the like. Of these, Eu ₂ O ₃ , EuCl _{2 and the} like are preferable, and Eu ₂ O ₃ is particularly preferable.

[Description of Si source]
As a Si raw material (Si source), it is preferable to use SiC, SiO ₂ or Si ₃ N ₄ , and more preferably Si ₃ N ₄ . It is also possible to use a compound as a SiO _2. Specific examples of such a compound include SiO ₂ , H ₄ SiO ₄ , Si (OCOCH ₃ ) _{4 and the} like. Further, Si ₃ N ₄ is preferably one having a small particle diameter and high purity in terms of light emission efficiency from the viewpoint of reactivity. Furthermore, from the viewpoint of luminous efficiency, β-Si ₃ N ₄ is more preferable than α-Si ₃ N ₄ , and in particular, one having a small content ratio of carbon elements as impurities is preferable. The smaller the carbon content, the better. However, the content is usually 0.01% by weight or more, usually 0.3% by weight or less, preferably 0.1% by weight or less, more preferably 0.05% by weight or less. is there.
On the other hand, from the viewpoint of increasing the particle size of the phosphor particles, it is preferable that the particle size of the raw material Si ₃ N ₄ is large.

[Other explanation about phosphor material]
In the various phosphor materials, it is preferable to use a phosphor material having high purity and higher whiteness. This is to increase the luminous efficiency of the obtained phosphor. Specifically, it is preferable to use a phosphor material having a reflectance in the wavelength range of 380 nm to 780 nm of usually 60% or more, preferably 70% or more, more preferably 80% or more. In particular, at 525 nm, which is a wavelength close to the emission peak wavelength of the phosphor of the present invention, the reflectance of the phosphor material is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more. Particularly preferably, it is 90% or more.

Of the plurality of phosphor materials, it is particularly preferable to use silicon nitride (Si ₃ N ₄ ) having a high reflectance. Further, as Si ₃ N ₄ satisfying the reflectance, the amount of carbon contained as an impurity is usually 0.2% by weight or less, preferably 0.1% by weight or less, more preferably 0.05% by weight. Hereinafter, it is more preferably 0.03% by weight or less. The amount of impurity carbon is preferably as small as possible, but is usually 0.001% by weight or more. In addition, this reflectance should just measure a reflection spectrum in accordance with well-known methods, such as the method as described in WO2009 / 017206 pamphlet.

In addition, silicon nitride (Si ₃ N ₄ ) is preferably β-type rather than α-type. Examples of such silicon nitride include those described in WO2009 / 017206.
Further, the N element in the composition of the phosphor of the present invention is usually supplied at the time of phosphor production as an anion component of the phosphor material of each phosphor constituent element or as a component contained in the firing atmosphere. The

[2-2. Production method of phosphor: mixing step]
The phosphor of the present invention is obtained by weighing the phosphor materials so that the target composition is obtained, mixing them, and firing. In this case, it is preferable that the mixing is sufficiently performed using a ball mill or the like.
Although it does not specifically limit as said mixing method, Specifically, the well-known method which was mentioned as following (A) and (B) can be used arbitrarily. As for these various conditions, for example, known conditions such as mixing and using two kinds of balls having different particle diameters in a ball mill can be appropriately selected.

(A) Dry pulverizer such as hammer mill, roll mill, ball mill, jet mill, etc.
Or, a dry mixing method in which pulverization using the mortar and pestle is combined with a mixing machine such as a ribbon blender, V-type blender, Henschel mixer, etc., or mixing using a mortar and pestle, and the above phosphor raw materials are pulverized and mixed. .
(B) An alcoholic solvent such as ethanol or a solvent or dispersion medium such as water is added to the phosphor raw material, and the mixture is mixed using, for example, a pulverizer, a mortar and pestle, or an evaporating dish and a stirring rod A wet mixing method in which the product is dried by spray drying, heat drying, natural drying, or the like.

Further, when mixing and pulverizing, the phosphor material may be sieved as necessary. In this case, various commercially available sieves can be used, but it is preferable to use a resin such as a nylon mesh rather than a metal mesh such as a metal mesh in terms of preventing impurities from being mixed.
The mixing of the phosphor raw materials may be arbitrarily selected from the above-mentioned wet type and dry type according to the physical properties of the phosphor raw materials.

In addition, when nitride is used as a raw material, an inert gas such as argon gas or nitrogen gas is filled, for example, so that the nitride is not deteriorated by moisture, and mixer mixing is performed in a moisture-controlled glove box. preferable.
Furthermore, when mixing, the moisture in the atmosphere is preferably 10,000 ppm or less, more preferably 1000 ppm or less, still more preferably 10 ppm or less, and particularly preferably 1 ppm or less. Further, oxygen is preferably 1% or less, more preferably 1000 ppm or less, still more preferably 100 ppm or less, and particularly preferably 10 ppm or less.

[2-3. Production method of phosphor: firing step]
A phosphor is obtained by firing the obtained mixture. This firing is preferably performed by filling the phosphor material in a container such as a crucible and firing at a predetermined temperature and atmosphere.
As the container, it is preferable to use a heat-resistant container such as a crucible or a tray made of a material having low reactivity with each phosphor raw material. Examples of the material of the heat-resistant container used at the time of firing include, for example, metals such as alumina, quartz, boron nitride, silicon nitride, silicon carbide, platinum, molybdenum, tungsten, tantalum, niobium, or alloys containing them as a main component. And carbon (graphite). Here, the heat-resistant container made of quartz can be used for heat treatment at a relatively low temperature, that is, 1200 ° C. or less, and a preferable use temperature range is 1000 ° C. or less.

  Examples of such heat-resistant containers are preferably boron nitride, alumina, silicon nitride, silicon carbide, platinum, molybdenum, tungsten, and tantalum heat-resistant containers, more preferably boron nitride. , Alumina, and molybdenum. In particular, when firing in a reducing atmosphere such as in a nitrogen-hydrogen mixed gas, quartz or alumina that is stable in the firing temperature range is preferable. However, since it may react with alumina depending on the kind of the phosphor raw material, it is preferable to use a heat-resistant container made of boron nitride or molybdenum.

In the temperature raising process at the time of firing, it is preferable that a part of the temperature is reduced. Specifically, at any time when the temperature is preferably room temperature or higher, and preferably 1500 ° C. or lower, more preferably 1200 ° C. or lower, and even more preferably 1000 ° C. or lower, the reduced pressure state (specific In general, it is preferably in the range of 10 ⁻² Pa or more and less than 0.1 MPa. Among them, it is preferable to introduce an inert gas or a reducing gas, which will be described later, into the system after reducing the pressure in the system and raise the temperature in that state.

At this time, if necessary, the target temperature may be maintained for 1 minute or longer, preferably 5 minutes or longer, more preferably 10 minutes or longer. The holding time is usually 5 hours or less, preferably 3 hours or less,
More preferably, it is 1 hour or less.
As the firing temperature for producing the phosphor of the present invention, a powder having good crystallinity is obtained at a firing temperature of around 1800 ° C. Therefore, the temperature is usually 1300 ° C or higher, more preferably 1400 ° C or higher, and usually 2000 ° C or lower, preferably 1900 ° C or lower.

Although it does not restrict | limit especially as a baking atmosphere, Usually, it carries out in inert gas atmosphere or reducing atmosphere. Here, as described above, the valence of the activating element is preferably a divalent one, so that a reducing atmosphere is preferable. In addition, only 1 type may be used for an inert gas and reducing gas, and 2 or more types may be used together by arbitrary combinations and a ratio.
Examples of the inert gas and the reducing gas include carbon monoxide, hydrogen, nitrogen, argon, methane, and ammonia. Of these, a nitrogen gas atmosphere is preferable, and a hydrogen gas-containing nitrogen gas atmosphere is more preferable. As the nitrogen (N ₂ ) gas, it is preferable to use a purity of 99.9% or more. When using hydrogen-containing nitrogen, it is preferable to reduce the oxygen concentration in the electric furnace to 20 ppm or less. Further, the hydrogen content in the atmosphere is preferably 1% by volume or more, more preferably 2% by volume or more, and 100% by volume or less of hydrogen gas may be used, but 10% by volume or less is preferable, and 5% by volume. The following is more preferable. This is because if the hydrogen content in the atmosphere is too high, the safety may decrease, and if it is too low, a sufficient reducing atmosphere may not be achieved.

Further, the inert gas and the reducing gas may be introduced before the start of temperature increase, may be introduced during the temperature increase, or may be introduced when the firing temperature is reached, but before the temperature increase is started. Or it is preferable to introduce in the middle of temperature rising.
Moreover, when calcination is performed under the flow of these inert gas and reducing gas, the calcination is usually performed at a flow rate of 0.1 to 10 liters / minute.

The firing time is usually 0.5 hours or longer, preferably 1 hour or longer, although it varies depending on the temperature and pressure during firing. The firing time is preferably longer, but is usually 100 hours or shorter, preferably 50 hours or shorter, more preferably 24 hours or shorter, and further preferably 12 hours or shorter.
The pressure at the time of firing is not particularly limited because it varies depending on the firing temperature or the like, but is usually 1 × 10 ⁻⁵ Pa or more, preferably 1 × 10 ⁻³ Pa or more, more preferably 0.01 MPa or more, and still more preferably 0.8. The upper limit is usually 5 GPa or less, preferably 1 GPa or less, more preferably 200 MPa or less, and still more preferably 100 MPa or less. Among these, the atmospheric pressure to about 1 MPa is industrially preferable in terms of cost and labor.
In the firing step, for example, a phosphor precursor other than the raw material mixture, such as a fired product obtained by mixing and firing a part or all of the phosphor raw materials, is combined with the raw material mixture, or they are replaced with the raw material mixture. Alternatively, it may be fired.

[2-4. flux]
In the phosphor of the present invention, a flux may coexist in the reaction system in the firing step. The type of flux is not particularly limited, _{examples, NH 4 Cl, NH 4 F} · HF , such as ammonium _halide; NaCO 3, alkali metal carbonates such as _{LiCO 3; LiCl, NaCl, KCl} , CsCl, LiF, Alkali metal halides such as NaF, KF, CsF; Alkaline earth metal halides such as CaCl ₂ , BaCl ₂ , SrCl ₂ , CaF ₂ , BaF ₂ , SrF ₂ ; EuCl ₂ , LaCl ₃ , CeCl ₃ , EuF ₂ Rare earth metal halides such as LaF ₃ , CeCl ₃ ; alkaline earth metal oxides such as CaO, SrO, BaO; B ₂ O ₃ , H ₃ BO ₃ , Na ₂ B ₄ O ₇ , K ₂ B ₄ O ₇ Boron oxide such as boric acid and borate compound of alkali metal or alkaline earth metal; Li ₃ PO ₄ , NH ₄ H ₂ PO ₄ , B aHP
Phosphate compounds such as O ₄ and Zn ₃ (PO ₄ ) ₂ ; Aluminum halides such as AlF ₃ ; Zinc halides such as ZnCl ₂ , ZnBr ₂ and ZnF ₂ , zinc oxide, zinc sulfide, zinc borate, phosphoric acid Zinc compounds such as zinc; periodic table group 15 element compounds such as Bi ₂ O ₃ ; Li ₃ N, Ca ₃ N ₂ , Sr ₃ N ₂ , Ba ₃ N ₂ , Sr ₂ N, Ba ₂ N, BN, etc. Alkali metals, alkaline earth metals, nitrides of Group 13 elements, and the like can be given.

The amount of flux used varies depending on the type of phosphor material, the type of flux, etc., but is usually 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 1% by weight or more for each flux. In addition, it is usually 20% by weight or less, more preferably 10% by weight or less.
In addition, only 1 type may be used for a flux and it may use 2 or more types together by arbitrary combinations and a ratio. When two or more types are used in combination, the amount of flux used is generally 40% by weight or less, preferably 30% by weight or less, more preferably 25% by weight or less. The total amount is usually 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 1% by weight or more.

[2-5. Multi-stage firing]
In order to further advance the solid-phase reaction and improve the crystallinity in the firing process, the firing process may be performed in multiple stages instead of one stage. For example, the raw material mixture obtained by the mixing step is first fired first (first firing step), then pulverized again with a ball mill or the like as necessary, and then fired again (second firing step). Do it at least once. The re-baking (second baking step) may be performed as many times as secondary baking or tertiary baking. At this time, the primary fired fired product may be introduced into the subsequent firing only with the fired product, or a part of the aforementioned phosphor raw material mixed and fired is pulverized and the remaining raw materials are mixed there And it can also take the aspect of baking.

The temperature of the primary firing is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 800 ° C. or higher, preferably 1000 ° C. or higher, and usually 1900 ° C. or lower, preferably 1800 ° C. or lower, more preferably 1700. It is the range below ℃.
Here, in order to obtain a phosphor having a uniform particle size, it is preferable to advance the solid phase reaction in a powder state by setting the primary firing temperature low. On the other hand, in order to obtain a high-luminance phosphor, it is preferable that the primary firing temperature is set high to produce a liquid phase and the raw materials are sufficiently mixed, and then the crystals are grown by secondary firing.

The primary firing time is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 hour or longer, preferably 2 hours or longer, and usually 100 hours or shorter, preferably 50 hours or shorter, more preferably 24 hours. The time is less than or equal to 12 hours or less.
Conditions such as temperature and time in firing after the secondary firing are basically the same as those described in the above-mentioned firing step column.

The flux may be mixed before the primary firing or may be mixed before firing after the secondary firing. Also, the firing conditions such as the atmosphere may be changed between the primary firing and the secondary firing and thereafter.
The firing conditions at this time are appropriately selected within the same range as described above. However, among the firing temperatures in the two consecutive firing steps, the one having at least one step of setting the latter firing temperature to a higher temperature promotes the crystal growth of the phosphor and improves the crystallinity. This is preferable because it can be increased.

[2-6. Refiring process]
As described above, the method for producing a phosphor according to the present invention includes a step of re-firing at a specific temperature after the phosphor firing step. By having this step, the durability of the phosphor of the present invention is improved.
The heat treatment temperature in the reheating step is usually 350 ° C. or higher, preferably 400 ° C. or higher, and usually 600 ° C. or lower, preferably 550 ° C. or lower, more preferably, although it depends on the atmosphere during the heat treatment. It is 500 degrees C or less.

As the atmosphere during the heat treatment in the reheating step, in addition to the same as described in the section of the firing step, an oxygen-containing inert gas such as air or oxygen-containing nitrogen can also be used. Is preferred.
In the case of using such an oxygen-containing gas, the oxygen concentration is usually preferably 1% or less.

Furthermore, from the viewpoint of suppressing a decrease in light emission intensity and light emission luminance, the refiring temperature is more preferably a temperature range of 350 ° C. to 450 ° C. in the case of an oxygen-containing atmosphere, and in the case of a nitrogen atmosphere. More preferably, a temperature range of 350 ° C. or higher and 550 ° C. or lower is mentioned.
The pressure at the time of the heat treatment in the reheating step may be the same as that described in the firing step.

The heat treatment time in the reheating step is usually 0.1 hour or longer, preferably 0.5 hour or longer. From the viewpoint of productivity, it is usually 100 hours or shorter, preferably 50 hours or shorter, more preferably 24 hours. Hereinafter, it is more preferably 12 hours or less.
By having this reheating process, distortion and defects in the phosphor crystal can be further reduced, the crystallinity of the phosphor can be improved, and modification of the phosphor surface can be expected, improving the durability of the phosphor. It is thought that it contributes to.

The re-baking step may be performed on the phosphor immediately after the firing step, but after the firing step, the phosphor after performing the below-described pulverization, washing, classification step, etc. preferable. In this case, it is preferable to have a step of washing with an acidic liquid medium such as an inorganic acid such as hydrochloric acid, nitric acid or sulfuric acid; or an aqueous solution of an organic acid such as acetic acid. In addition, when it has the process wash | cleaned with an acidic liquid medium, it is preferable to wash | clean further with water before a rebaking process so that an acid may not remain on fluorescent substance.
Further, the reheating treatment may be performed a plurality of times by changing the atmosphere. In that case, the treatment atmosphere may be changed by each reheating treatment, such as performing the reheating treatment in an H ₂ containing atmosphere after the reheating treatment in an oxygen containing atmosphere.

[2-7. Post-processing]
After the heat treatment in the above-described firing step, pulverization, washing, drying, classification treatment, and the like are performed as necessary.
[Crushing treatment]
The pulverization treatment is performed on the fired product, for example, when the obtained phosphor does not have a desired particle size. The pulverization method is not particularly limited. For example, the dry pulverization method and the wet pulverization method described in the description of the phosphor raw material mixing step can be used, but the destruction of the generated phosphor crystal is suppressed, and the target treatment such as secondary particle crushing is performed. In order to proceed, for example, balls such as alumina, silicon nitride, ZrO ₂ , glass or the like, or balls such as iron core urethane are put into a container and ball milling is performed for about 10 minutes to 24 hours. Is preferred. In this case, you may use 0.05-2 weight% of dispersing agents, such as alkali phosphates, such as organic acid and hexametaphosphoric acid.

[Cleaning treatment]
The cleaning treatment can be performed, for example, with water such as deionized water, an organic solvent such as ethanol, or an alkaline aqueous solution such as ammonia water. For the purpose of removing the impurity phase adhering to the surface of the phosphor such as used flux and improving the light emission characteristics, for example, inorganic acids such as hydrochloric acid, nitric acid and sulfuric acid; or organic such as acetic acid An aqueous acid solution can also be used. In this case, it is preferable to further wash with water after washing in an acidic aqueous solution.

As the degree of washing, it is preferable that the pH of the supernatant obtained by dispersing the washed phosphor in water 10 times by weight and allowing it to stand for 1 hour is neutral (about pH 7 to 9). This is because if it is biased to basic or acidic, the liquid medium or the like may be affected when mixed with the liquid medium or the like described later.
The degree of washing can also be expressed by the electrical conductivity of the supernatant obtained by dispersing the washed phosphor in 10 times the weight ratio of water and allowing it to stand for 1 hour. The electrical conductivity is preferably as low as possible from the viewpoint of light emission characteristics, but in consideration of productivity, the washing treatment is usually repeated until it is 10 mS / m or less, preferably 5 mS / m or less, more preferably 4 mS / m or less. It is preferable.

As a method for measuring electrical conductivity, phosphor particles having a specific gravity heavier than water are obtained by stirring and dispersing in water 10 times the weight of the phosphor for a predetermined time, for example, 10 minutes, and then allowing to stand for 1 hour. The electrical conductivity of the supernatant liquid at this time may be measured using an electrical conductivity meter “EC METER CM-30G” manufactured by Toa Decay Co., Ltd. Although there is no restriction | limiting in particular as water used for a washing process and a measurement of electrical conductivity, Demineralized water or distilled water is preferable. Among them, those having particularly low electric conductivity are preferable, and those having a conductivity of usually 0.0064 mS / m or more, and usually 1 mS / m or less, preferably 0.5 mS / m or less are used. The electrical conductivity is usually measured at room temperature (about 25 ° C.).
In addition, the cleaning treatment can be performed, for example, in the same manner as the cleaning step performed between the first baking step and the second baking step.

[Classification processing]
The classification treatment can be performed, for example, by performing a water sieving or water tank treatment, or by using various classifiers such as various air classifiers or vibrating sieves. In particular, when dry classification using nylon mesh and water tank treatment are used in combination, a phosphor with good dispersibility having a weight median diameter of about 20 μm can be obtained.

  Here, in the water sieving or elutriation treatment, the aqueous medium is usually used to disperse the phosphor particles at a concentration of about 0.1 to 10% by weight in the aqueous medium and to suppress the deterioration of the phosphor. The pH is usually 4 or more, preferably 5 or more, and usually 9 or less, preferably 8 or less. Further, when obtaining phosphor particles having a weight median diameter as described above, in the water sieving and elutriation treatment, for example, particles of 50 μm or less are obtained, and then particles of 30 μm or less are obtained. Is preferable from the viewpoint of balance between work efficiency and yield. Moreover, as a minimum, it is preferable to perform the process of sieving a thing normally 1 micrometer or more, Preferably 5 micrometers or more.

〔surface treatment〕
Resin in the phosphor-containing portion of the light-emitting device described later in order to further improve the weather resistance such as moisture resistance when the light-emitting device is manufactured by the method described later using the obtained phosphor of the present invention In order to improve the dispersibility, a known surface treatment method such as coating the surface of the phosphor with a different substance may be performed as necessary.

3. Phosphor-containing composition The phosphor of the present invention can be used by mixing with a liquid medium. In particular, when the phosphor of the present invention is used for applications such as a light emitting device, it is preferably used in a form dispersed in a liquid medium. The phosphor of the present invention dispersed in a liquid medium will be referred to as “the phosphor-containing composition of the present invention” as appropriate.

[3-1. Phosphor]
There is no restriction | limiting in the kind of fluorescent substance of this invention contained in the fluorescent substance containing composition of this invention, It can select arbitrarily from what was mentioned above. Moreover, the fluorescent substance of this invention contained in the fluorescent substance containing composition of this invention may be only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. Furthermore, the phosphor-containing composition of the present invention may contain a phosphor other than the phosphor of the present invention as long as the effects of the present invention are not significantly impaired.

[3-2. Liquid medium]
The kind of the liquid medium used for the phosphor-containing composition of the present invention is not particularly limited, and a curable material that can be molded over the semiconductor light emitting element can be used. The curable material is a fluid material that is cured by performing some kind of curing treatment. Here, the fluid state means, for example, a liquid state or a gel state. The curable material is not particularly limited as long as it secures the role of guiding the light emitted from the solid light emitting element to the phosphor. Moreover, only 1 type may be used for a curable material and it may use 2 or more types together by arbitrary combinations and a ratio. Therefore, as the curable material, any of inorganic materials, organic materials, and mixtures thereof can be used.

As the inorganic material, for example, a solution obtained by hydrolytic polymerization of a solution containing a metal alkoxide, a ceramic precursor polymer or a metal alkoxide by a sol-gel method, or a combination thereof is solidified (for example, a siloxane bond). Inorganic materials having
On the other hand, examples of the organic material include a thermosetting resin and a photocurable resin. Specific examples include (meth) acrylic resins such as methyl poly (meth) acrylate; styrene resins such as polystyrene and styrene-acrylonitrile copolymer; polycarbonate resins; polyester resins; phenoxy resins; butyral resins; Cellulose resins such as cellulose acetate and cellulose acetate butyrate; epoxy resins; phenol resins; silicone resins.

  Among these curable materials, the phosphor-containing composition of the present invention preferably uses a silicon-containing compound that has little deterioration with respect to light emission from a semiconductor light-emitting device and is excellent in alkali resistance, acid resistance, and heat resistance. . The silicon-containing compound is a compound having a silicon atom in the molecule, organic materials such as polyorganosiloxane (silicone compound), inorganic materials such as silicon oxide, silicon nitride, silicon oxynitride, borosilicate, phosphosilicate Examples thereof include glass materials such as salts and alkali silicates. Of these, silicone materials are preferred from the viewpoints of transparency, adhesion, ease of handling, mechanical and thermal adaptability relaxation characteristics, and the like.

The silicone-based material usually refers to an organic polymer having a siloxane bond as a main chain, and for example, condensation-type, addition-type, improved sol-gel type, photo-curing type silicone-based materials can be used.
As the condensed silicone material, for example, semiconductor light-emitting device members described in JP-A-2007-112973 to 112975, JP-A-2007-19459, JP-A-2008-34833, and the like can be used. Condensation-type silicone materials have excellent adhesion to components such as packages, electrodes, and light-emitting elements used in semiconductor light-emitting devices, so the addition of adhesion-improving components can be minimized, and crosslinking is mainly due to siloxane bonds. There is an advantage of excellent heat resistance and light resistance.

Examples of the addition-type silicone material include potting silicone materials described in JP-A-2004-186168, JP-A-2004-221308, JP-A-2005-327777, JP-A-2003-183881, Organically modified silicone materials for potting described in JP-A-2006-206919, silicone materials for injection molding described in JP-A-2006-324596, silicone materials for transfer molding described in JP-A-2007-231173, etc. Can be suitably used. The addition-type silicone material has advantages such as a high degree of freedom in selection such as a curing speed and a hardness of a cured product, a component that does not desorb during curing, hardly shrinking due to curing, and excellent deep part curability.

  Moreover, as an improved sol-gel type silicone material that is one of the condensation types, for example, the silicone materials described in JP-A-2006-077234, JP-A-2006-291018, JP-A-2007-119569 and the like can be used. It can be used suitably. The improved sol-gel type silicone material has an advantage that it has a high degree of crosslinking, heat resistance, light resistance and durability, and is excellent in the protective function of a phosphor having low gas permeability and low moisture resistance.

As the photocurable silicone material, for example, silicone materials described in JP 2007-131812 A, JP 2007-214543 A, and the like can be suitably used. The ultraviolet curable silicone material has advantages such as excellent productivity because it cures in a short time, and there is no need to apply a high temperature for curing, and the light emitting element is hardly deteriorated.
These silicone materials may be used alone, or a mixture of a plurality of silicone materials may be used if curing inhibition does not occur when mixed.

[3-3. Content ratio of liquid medium and phosphor]
The content of the liquid medium is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 25% by weight or more, preferably 40% by weight or more, based on the entire phosphor-containing composition of the present invention. The amount is usually 99% by weight or less, preferably 95% by weight or less, more preferably 80% by weight or less. When the amount of the liquid medium is large, no particular problem occurs. However, in order to obtain a desired chromaticity coordinate, color rendering index, luminous efficiency, etc. in the case of a semiconductor light emitting device, it is usually at a blending ratio as described above. It is desirable to use a liquid medium. On the other hand, when there is too little liquid medium, fluidity | liquidity may fall and it may become difficult to handle.

  The liquid medium mainly serves as a binder in the phosphor-containing composition of the present invention. The liquid medium may be used alone or in combination of two or more in any combination and ratio. For example, when using a silicon-containing compound for the purpose of improving heat resistance, light resistance, etc., other thermosetting resins such as an epoxy resin are contained so as not to impair the durability of the silicon-containing compound. Also good. In this case, the content of the other thermosetting resin is usually 25% by weight or less, preferably 10% by weight or less based on the total amount of the liquid medium as the binder.

  The content of the phosphor in the phosphor-containing composition of the present invention is arbitrary as long as the effects of the present invention are not significantly impaired, but usually 1% by weight or more with respect to the entire phosphor-containing composition of the present invention, Preferably it is 5 weight% or more, More preferably, it is 20 weight% or more, and is 75 weight% or less normally, Preferably it is 60 weight% or less. The proportion of the phosphor of the present invention in the phosphor in the phosphor-containing composition is also arbitrary, but is usually 30% by weight or more, preferably 50% by weight or more, and usually 100% by weight or less. If the phosphor content in the phosphor-containing composition is too high, the flowability of the phosphor-containing composition may be inferior and difficult to handle, and if the phosphor content is too low, the light emission efficiency of the light-emitting device decreases. There is a tendency.

[3-4. Other ingredients]
In the phosphor-containing composition of the present invention, other than the phosphor and the liquid medium, for example, a metal oxide for adjusting the refractive index described later, or a diffusing agent, unless the effect of the present invention is significantly impaired. Additives such as fillers, viscosity modifiers, and UV absorbers may be included. Only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and a ratio.

4. Light-Emitting Device A light-emitting device of the present invention (hereinafter appropriately referred to as “light-emitting device”) includes a first light emitter (excitation light source) and a second light source that emits visible light when irradiated with light from the first light emitter. And a first phosphor containing at least one phosphor of the present invention described in the above-mentioned section “1, Phosphor” as the second light emitter. Is.

  As the phosphor of the present invention, a phosphor that emits fluorescence in the red region under irradiation of light from an excitation light source (hereinafter sometimes referred to as “the red phosphor of the present invention”) is usually used. The red phosphor of the present invention preferably has an emission peak in a wavelength range of 550 nm to 700 nm. Any one of the red phosphors of the present invention may be used alone, or two or more thereof may be used in any combination and ratio.

By using the red phosphor of the present invention, the light-emitting device of the present invention exhibits high luminous efficiency with respect to an excitation light source (first light-emitting body) that emits light in a blue region. When used in a white light emitting device such as a display light source, the light emitting device is excellent.
In addition, preferred specific examples of the red phosphor of the present invention used in the light emitting device of the present invention include the phosphor of the present invention described in the above-mentioned “1, Phosphor” column, and the [Example] described later. The phosphor used in each example in the column is listed.

The light-emitting device of the present invention has a first light emitter (excitation light source), and at least the phosphor of the present invention is used as the second light emitter. It is possible to arbitrarily adopt the apparatus configuration. A specific example of the device configuration will be described later.
The light emission peak in the red region of the light emission spectrum of the light emitting device of the present invention preferably has a light emission peak in the wavelength range of 600 nm to 650 nm.

  Note that the emission spectrum of the light emitting device is measured by energizing 20 mA with a color / illuminance measurement software and USB2000 series spectroscope (integral sphere specification) manufactured by Ocean Optics in a room maintained at a temperature of 25 ± 1 ° C. Can be done. Chromaticity values (x, y, z) can be calculated as chromaticity coordinates in the XYZ color system defined by JIS Z8701 from data in the wavelength region of 380 nm to 780 nm of the emission spectrum. In this case, the relational expression x + y + z = 1 holds. In the present specification, the XYZ color system may be referred to as an XY color system, and is usually expressed as (x, y).

  The light emitting device of the present invention preferably has a light emission efficiency of usually 10 lm / W or more, particularly 30 lm / W or more, particularly 50 lm / W or more. The luminous efficiency is obtained by obtaining the total luminous flux from the result of the emission spectrum measurement using the light emitting device as described above and dividing the lumen (lm) value by the power consumption (W). The power consumption is obtained by measuring a voltage using a True RMS Multimeters Model 187 & 189 manufactured by Fluke in a state in which 20 mA is energized, and obtaining the product of the current value and the voltage value.

Among the light emitting devices of the present invention, in particular, as a white light emitting device, specifically, an excitation light source as described later is used as the first light emitter, and in addition to the red phosphor as described above, a blue light source as described later is used. A phosphor that emits fluorescence (hereinafter referred to as “blue phosphor” as appropriate), a phosphor that emits green fluorescence (hereinafter referred to as “green phosphor” as appropriate), and a phosphor that emits yellow fluorescence (hereinafter referred to as “yellow fluorescence” as appropriate). It is obtained by using known phosphors such as “body”) in any combination and adopting a known device configuration.
Here, the white color of the white light emitting device means all of (yellowish) white, (greenish) white, (blueish) white, (purple) white and white defined by JIS Z 8701 Of these, white is preferred.

[4-1. Configuration of light emitting device]
<4-1-1. First luminous body>
The 1st light-emitting body in the light-emitting device of this invention light-emits the light which excites the 2nd light-emitting body mentioned later.
The emission peak wavelength of the first illuminant is not particularly limited as long as it overlaps with the absorption wavelength of the second illuminant described later, and an illuminant having a wide emission wavelength region can be used. Usually, an illuminant having an emission wavelength from the ultraviolet region to the blue region is used, and it is particularly preferable to use an illuminant having an emission wavelength in the blue region.

  As a specific numerical value of the emission peak wavelength of the first illuminant, 200 nm or more is usually desirable. Among these, when blue light is used as excitation light, it is usually 420 nm or more, preferably 430 nm or more, more preferably 440 nm or more, and usually 500 nm or less, preferably 480 nm or less, more preferably 470 nm or less, and even more preferably 460 nm. It is desirable to use a light emitter having the following emission peak wavelength. On the other hand, when near-ultraviolet light is used as excitation light, the phosphor of the present invention is excited by blue light from a phosphor that emits blue light when excited by near-ultraviolet light. It is preferable to select excitation light (near ultraviolet light) having a wavelength suitable for the band. Specifically, it is desirable to use a luminescent material having an emission peak wavelength of usually 300 nm or more, preferably 330 nm or more, more preferably 360 nm or more, and usually 420 nm or less, preferably 410 nm or less, more preferably 400 nm or less. .

  As the first light emitter, a semiconductor light emitting element is generally used, and specifically, a light emitting diode (LED), a laser diode (LD), or the like can be used. In addition, as a light-emitting body which can be used as a 1st light-emitting body, an organic electroluminescent light emitting element, an inorganic electroluminescent light emitting element, etc. are mentioned, for example. However, what can be used as a 1st light-emitting body is not restricted to what is illustrated by this specification.

Among these, as the first light emitter, a GaN LED or LD using a GaN compound semiconductor is preferable. This is because GaN-based LEDs and LDs have significantly higher emission output and external quantum efficiency than SiC-based LEDs that emit light in this region, and emit very bright light with low power when combined with the phosphor. It is because it is obtained. For example, for a current load of 20 mA, GaN-based LEDs and LDs usually have a light emission intensity 100 times or more that of SiC-based. As the GaN-based LED and LD, those having an Al _X Ga _Y N light emitting layer, a GaN light emitting layer, or an In _X Ga _Y N light emitting layer are preferable. Among them, since the emission intensity is very high, the GaN-based LED is particularly preferably one having an In _X Ga _Y N light emitting layer, and more preferably a multiple quantum well structure having an In _X Ga _Y N layer and a GaN layer. preferable.

In the above, the value of X + Y is usually a value in the range of 0.8 to 1.2. In the GaN-based LED, those in which the light emitting layer is doped with Zn or Si or those without a dopant are preferable for adjusting the light emission characteristics.
A GaN-based LED has these light-emitting layer, p-layer, n-layer, electrode, and substrate as basic components, and the light-emitting layer is an n-type and p-type Al _X Ga _Y N layer, GaN layer, or In _X Those having a heterostructure sandwiched between Ga _Y N layers and the like are preferable because of high light emission efficiency, and those having a heterostructure having a quantum well structure are more preferable because of high light emission efficiency.
Note that only one first light emitter may be used, or two or more first light emitters may be used in any combination and ratio.

<4-1-2. Second luminous body>
The second light emitter in the light emitting device of the present invention is a light emitter that emits visible light when irradiated with light from the first light emitter described above, and contains the first phosphor including the red phosphor of the present invention. In addition, a second fluorescent material (a blue fluorescent material, a green fluorescent material, a yellow fluorescent material, an orange fluorescent material, etc.), which will be described later, is appropriately contained in accordance with the application. Further, for example, the second light emitter is configured by dispersing the first and second phosphors in a sealing material.

Used for the in the second luminescent material is not particularly limited to the phosphor composition other than the phosphor of the present invention, the host _{crystal, Y 2 O 3, YVO 4} , Zn 2 SiO 4, Y 3 Metal oxides typified by Al ₅ O ₁₂ , Sr ₂ SiO ₄ , metal nitrides typified by (Ca, Sr) AlSiN ₃ , phosphates typified by Ca ₅ (PO ₄ ) ₃ Cl, etc. And CeS, Pr, Nd, Pm, Sm, Eu, Tb, Dy, sulfides typified by ZnS, SrS, CaS, etc., oxysulfides typified by Y ₂ O ₂ S, La ₂ O ₂ S, etc. , Ho, Er, Tm, Yb, and other rare earth metal ions, and Ag, Cu, Au, Al, Mn, Sb, and other metal ions are combined as activators or coactivators.

  Specific examples of preferred crystal matrixes are shown in the following table.

  However, the matrix crystal and the activator element or coactivator element are not particularly limited in element composition, and can be partially replaced with elements of the same family, and the obtained phosphor is light in the near ultraviolet to visible region. Any material that absorbs and emits visible light can be used.

  Specifically, the following phosphors can be used, but these are merely examples, and phosphors that can be used in the present invention are not limited to these. In the following examples, as described above, phosphors that differ only in part of the structure are omitted as appropriate.

<4-1-2-1. First phosphor>
The 2nd light-emitting body in the light-emitting device of this invention contains the 1st fluorescent substance containing the fluorescent substance of the above-mentioned this invention at least. Any one of the phosphors of the present invention may be used alone, or two or more thereof may be used in any combination and ratio.
In addition to the phosphor of the present invention, a phosphor that emits fluorescence of the same color as the phosphor of the present invention (same color combined phosphor) may be used as the first phosphor. Usually, the phosphor of the present invention is a red phosphor. Therefore, as the first phosphor, other types of red phosphors or phosphors emitting orange fluorescence (hereinafter referred to as “orange phosphors” as appropriate). Can be used in combination.

  The weight median diameter of the first phosphor used in the light emitting device of the present invention is usually in the range of 2 μm or more, especially 5 μm or more, and usually 30 μm or less, especially 20 μm or less. When the weight median diameter is too small, the luminance is lowered and the phosphor particles tend to aggregate. On the other hand, if the weight median diameter is too large, there is a tendency for coating unevenness and blockage of the dispenser to occur.

Any orange or red phosphor that can be used in combination with the phosphor of the present invention can be used as long as the effects of the present invention are not significantly impaired.
At this time, the emission peak wavelength of the orange to red phosphor, which is the same color combination phosphor, is usually 570 nm or more, preferably 580 nm or more, more preferably 585 nm or more, and usually 780 nm or less, preferably 700 nm or less, more preferably 680 nm. It is preferable to be in the following wavelength range.

  The phosphors that can be used as such orange or red phosphors are shown in the following table.

Among these, as red phosphors, (Ca, Sr, Ba) ₂ Si ₅ (N, O) ₈ : Eu, (Ca, Sr, Ba) Si (N, O) ₂ : Eu, (Ca, Sr , Ba) AlSi (N, O) ₃ : Eu, (Sr, Ba) ₃ SiO ₅ : Eu, (Ca, Sr) S: Eu, (La, Y) ₂ O ₂ S: Eu, Eu (dibenzoylmethane) ) ₃ · 1,10-phenanthroline complexes of β- diketone Eu complex, a carboxylic acid Eu _complex, K 2 _SiF 6: Mn is _{preferred, (Ca, Sr, Ba)} 2 Si 5 (N, O) 8: Eu, (Sr, Ca) AlSi (N, O): Eu, (La, Y) ₂ O ₂ S: Eu, and K ₂ SiF ₆ : Mn are more preferable.

As the orange phosphor, (Sr, Ba) ₃ SiO ₅ : Eu, (Sr, Ba) ₂ SiO ₄ : Eu, (Ca, Sr, Ba) ₂ Si ₅ (N, O) ₈ : Eu, ( (Ca, Sr, Ba)
AlSi (N, O) ₃ : Ce is preferred.

<4-1-2-2. Second phosphor>
The second light emitter in the light emitting device of the present invention may contain a phosphor (that is, a second phosphor) in addition to the first phosphor described above, depending on the application. The second phosphor is one or more phosphors having different emission peak wavelengths from the first phosphor. Usually, since these second phosphors are used to adjust the color tone of light emitted from the second light emitter, the second phosphor emits fluorescence having a color different from that of the first phosphor. Often phosphors are used. As described above, since a red phosphor is usually used as the first phosphor, examples of the second phosphor include phosphors other than the red phosphor such as a blue phosphor, a green phosphor, and a yellow phosphor. Is used.

Second phosphor weight-average median diameter D ₅₀ of which is used for the light emitting device of the present invention is usually 2μm or more and preferably 5μm or more, and usually 30μm or less is preferably in a range of inter alia 20μm or less. When the weight-average median diameter D ₅₀ is too small, and the luminance decreases tends to phosphor particles tend to aggregate. On the other hand, if the weight median diameter is too large, there is a tendency for coating unevenness and blockage of the dispenser to occur.

<Blue phosphor>
When a blue phosphor is used in addition to the phosphor of the present invention, any blue phosphor can be used as long as the effects of the present invention are not significantly impaired. At this time, the emission peak wavelength of the blue phosphor is usually 420 nm or more, preferably 430 nm or more, more preferably 440 nm or more, and usually less than 500 nm, preferably 490 nm or less, more preferably 480 nm or less, more preferably 470 nm or less, It is particularly preferable that the wavelength range is 460 nm or less. When the emission peak wavelength of the blue phosphor used is within this range, it overlaps with the excitation band of the phosphor of the present invention, and the phosphor of the present invention can be efficiently excited by the blue light from the blue phosphor. Because.
The following table shows phosphors that can be used as such blue phosphors.

Among these, as the blue phosphor, (Ca, Sr, Ba) MgAl ₁₀ O ₁₇ : Eu, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ (Cl, F) ₂ : Eu, (Ba , Ca, Mg, Sr) ₂ SiO ₄ : Eu, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ (Cl, F) ₂ : Eu, (Ba, Ca, Sr) ₃ MgSi ₂ O ₈ : Eu is preferred, (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu, (Ca, Sr, Ba) ₁₀ (PO ₄ ) ₆ (Cl, F) ₂ : Eu, Ba ₃ MgSi ₂ O ₈ : Eu is more preferred, Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, BaMgAl ₁₀ O ₁₇ : Eu are particularly preferable.

<Green phosphor>
When a green phosphor is used in addition to the phosphor of the present invention, any green phosphor can be used as long as the effects of the present invention are not significantly impaired. At this time, the emission peak wavelength of the green phosphor is preferably in the range of usually 500 nm or more, particularly 510 nm or more, more preferably 515 nm or more, and usually less than 550 nm, especially 542 nm or less, more preferably 535 nm or less. If this emission peak wavelength is too short, it tends to be bluish, while if it is too long, it tends to be yellowish, and the characteristics as green light may deteriorate.
The phosphors that can be used as such green phosphors are shown in the table below.

Among these, as the green phosphor, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, CaSc ₂ O ₄ : Ce, Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce, (Sr, Ba) ₂ SiO ₄ : Eu, (Si, Al) ₆ (O, N) ₈ : Eu (β-sialon), (Ba, Sr) ₃ Si ₆ O ₁₂ : N ₂ : Eu, SrGa ₂ S ₄ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, Mn is preferred.

When the obtained light-emitting device is used for a lighting device, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, CaSc ₂ O ₄ : CeCa ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce, (Sr, Ba ) ₂ SiO ₄ : Eu, (Si, Al) ₆ (O, N) ₈ : Eu (β-sialon), (Ba, Sr) ₃ Si ₆ O ₁₂ : N ₂ : Eu are preferable.
When the obtained light emitting device is used for an image display device, (Sr, Ba) ₂ SiO ₄ : Eu, (Si, Al) ₆ (O, N) ₈ : Eu (β-sialon), (Ba, _{sr) 3 Si 6 O 12:} N 2: Eu, SrGa 2 S 4: Eu, BaMgAl 10 O 17: Eu, Mn are preferable.

<Yellow phosphor>
When a yellow phosphor is used in addition to the phosphor of the present invention, any yellow phosphor can be used as long as the effects of the present invention are not significantly impaired. At this time, the emission peak wavelength of the yellow phosphor is usually in the wavelength range of 530 nm or more, preferably 540 nm or more, more preferably 550 nm or more, and usually 620 nm or less, preferably 600 nm or less, more preferably 580 nm or less. Is preferred.

  The phosphors that can be used as such yellow phosphors are shown in the table below.

More in even, as the yellow _{phosphor, Y 3 Al 5 O 12:} Ce, (Y, Gd) 3 Al 5 O 12: Ce, (Sr, Ca, Ba, Mg) 2 SiO 4: Eu, (Ca, Sr) Si ₂ N ₂ O ₂ : Eu is preferred.

Specifically, when the semiconductor light emitting device of the present invention is configured as a white light emitting device, the semiconductor light emitting element, the nitride phosphor activated by Eu ²⁺ of the present invention, and other phosphors are preferable. Examples of combinations include the following combinations (A) to (C).
(A) A blue light emitter (blue LED or the like) is used as a semiconductor light emitting element, a nitride phosphor activated with Eu ²⁺ of the present invention is used as a red phosphor, and a green phosphor or another phosphor is used. A yellow phosphor is used. As the green phosphor, (Ba, Sr, Ca, Mg) ₂ SiO ₄ : Eu phosphor, (Ca, Sr) Sc ₂ O ₄ : Ce phosphor, Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce-based phosphor, SrGa ₂ S ₄ : Eu-based phosphor, Eu-activated β-sialon-based phosphor, (Mg, Ca, Sr, Ba) Si ₂ O ₂ N ₂ : Eu-based phosphor, and M _One or two or more green phosphors selected from the group consisting of ₃ Si ₆ O ₁₂ N ₂ : Eu (where M represents an alkaline earth metal element) are preferred. The yellow phosphor may be one selected from the group consisting of Y ₃ Al ₅ O ₁₂ : Ce phosphor, (Ba, Sr, Ca, Mg) ₂ SiO ₄ : Eu phosphor, and α-sialon phosphor. Two or more yellow phosphors are preferred. A green phosphor and a yellow phosphor may be used in combination.

(B) A near-ultraviolet light emitter (near-ultraviolet LED or the like) is used as a semiconductor light emitting device, a nitride phosphor activated with Eu ²⁺ of the present invention is used as a red phosphor, and blue fluorescence is used as another phosphor. Body and green phosphor. In this case, blue phosphors include (Ba, Sr, Ca) MgAl ₁₀ O ₁₇ : Eu, (Sr, Ba) ₃ MgSi ₂ O ₈ : Eu, and (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ). ) ₆ (Cl, F) ₂ : One or more blue phosphors selected from the group consisting of Eu are preferable. Further, as the green phosphor, in addition to the green phosphor exemplified in the above section (A), (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu, Mn, (Ba, Sr, Ca) ₄ Al ₁₄ O ₂₅ : Eu and (Ba, Sr, Ca) Al ₂ O ₄ : One or more green phosphors selected from the group consisting of Eu are preferable.

(C) A blue light emitter (blue LED or the like) is used as a semiconductor light emitting element, a nitride phosphor activated with Eu ²⁺ of the present invention is used as a red phosphor, and an orange phosphor is further used. In this case, (Sr, Ba) ₃ SiO ₅ : Eu is preferable as the orange phosphor.
Further, the combination of the phosphors described above will be described more specifically below.
When a blue light emitting element such as a blue LED is used as a semiconductor light emitting element and used for a backlight of an image display device, the combinations shown in the following table are preferable.

また、表６に示した組み合わせの中でもより好ましい組み合わせを表７に示す。

Table 7 shows more preferable combinations among the combinations shown in Table 6.

さらに、特に好ましい組み合わせを表８に示す。

Further, particularly preferred combinations are shown in Table 8.

表６〜８に示す各色蛍光体は、青色領域の光で励起され、それぞれ赤色領域、および緑色領域で発光し、かつ温度変化による発光ピーク強度の変化が少ないという優れた温度特性を有している。

Each color phosphor shown in Tables 6 to 8 has an excellent temperature characteristic that is excited by light in the blue region, emits light in the red region and the green region, respectively, and has little change in emission peak intensity due to temperature change. Yes.

Therefore, by combining two or more kinds of phosphors including these color phosphors with a semiconductor light emitting element that emits light in the blue region, the light emission efficiency for the color image display device of the present invention can be set higher than before. It can be set as the semiconductor light-emitting device suitable for the light source used for a light.
When a solid light emitting element that emits light in the near ultraviolet to ultraviolet region and a phosphor are used in combination, the phosphor combinations shown in Tables 6 to 8 above are further combined with (Sr, Ca, Ba, Mg) ₁₀ ( PO ₄ ) ₆ (Cl, F): Eu, and (Sr, Ba) ₃ MgSi ₂ O ₈ : Eu, (Ba, Sr, Ca) MgAl ₁₀ O ₁₇ : Eu selected from the group consisting of Eu It is preferable to combine phosphors, and it is more preferable to combine (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ (Cl, F): Eu or (Ba, Sr, Ca) MgAl ₁₀ O ₁₇ : Eu. preferable. At this time, it is preferable to combine BaMgAl ₁₀ O ₁₇ : Eu, Mn as the green phosphor.

[4-2. Embodiment of Light Emitting Device]
Hereinafter, the light-emitting device of the present invention will be described in more detail with reference to specific embodiments. However, the present invention is not limited to the following embodiments, and does not depart from the gist of the present invention. It can be implemented with arbitrary modifications.
FIG. 1 is a schematic perspective view showing a positional relationship between a first light emitter serving as an excitation light source and a second light emitter configured as a phosphor containing portion having a phosphor in an example of the light emitting device of the present invention. Shown in In FIG. 1, reference numeral 1 denotes a phosphor-containing portion (second light emitter), reference numeral 2 denotes a surface-emitting GaN-based LD as an excitation light source (first light emitter), and reference numeral 3 denotes a substrate. In order to create a state in which they are in contact with each other, LD (2) and phosphor-containing portion (second light emitter) (1) are produced separately, and their surfaces are brought into contact with each other by an adhesive or other means. Alternatively, the phosphor-containing portion (second light emitter) may be formed (molded) on the light emitting surface of the LD (2). As a result, the LD (2) and the phosphor-containing portion (second light emitter) (1) can be brought into contact with each other.

When such an apparatus configuration is employed, the light loss is such that light from the excitation light source (first light emitter) is reflected by the film surface of the phosphor-containing portion (second light emitter) and oozes out. Therefore, the light emission efficiency of the entire device can be improved.
FIG. 2A is a typical example of a light emitting device of a form generally referred to as a shell type, and has a light emission having an excitation light source (first light emitter) and a phosphor-containing portion (second light emitter). It is typical sectional drawing which shows one Example of an apparatus. In the light emitting device (4), reference numeral 5 denotes a mount lead, reference numeral 6 denotes an inner lead, reference numeral 7 denotes an excitation light source (first light emitter), reference numeral 8 denotes a phosphor-containing portion, reference numeral 9 denotes a conductive wire, reference numeral 10 Indicates a mold member.

  FIG. 2B is a representative example of a light-emitting device in a form called a surface-mount type, and light emission having an excitation light source (first light emitter) and a phosphor-containing portion (second light emitter). It is typical sectional drawing which shows one Example of an apparatus. In the figure, reference numeral 22 is an excitation light source (first light emitter), reference numeral 23 is a phosphor-containing portion (second light emitter), reference numeral 24 is a frame, reference numeral 25 is a conductive wire, reference numerals 26 and 27 are electrodes. Respectively.

[4-3. Application of light emitting device]
The use of the light-emitting device of the present invention is not particularly limited, and can be used in various fields in which ordinary light-emitting devices are used. However, since the color rendering property is high and the color reproduction range is wide, the illumination device is particularly preferable. And as a light source for image display devices.
<4-3-1. Lighting device>
When the light-emitting device of the present invention is applied to a lighting device, the above-described light-emitting device may be appropriately incorporated into a known lighting device. For example, a surface-emitting illumination device (11) incorporating the above-described light-emitting device (4) as shown in FIG. 3 can be mentioned.

FIG. 3 is a cross-sectional view schematically showing one embodiment of the illumination device of the present invention. As shown in FIG. 3, the surface-emitting illumination device has a number of light-emitting devices (13) (described above) on the bottom surface of a rectangular holding case (12) whose inner surface is light-opaque such as a white smooth surface. A light emitting device (4)), and a power source and a circuit (not shown) for driving the light emitting device (13) are provided outside the light emitting device (4).
A diffusion plate (14) such as a milky white acrylic plate is fixed at a position corresponding to the lid of the holding case (12) for uniform light emission.

  Then, the surface emitting illumination device (11) is driven to apply light to the excitation light source (first light emitter) of the light emitting device (13) to emit light, and part of the light emission is converted into the phosphor. The phosphor in the phosphor-containing resin part as the containing part (second light emitter) absorbs and emits visible light, while having high color rendering due to color mixing with blue light or the like that is not absorbed by the phosphor. Luminescence is obtained, and this light is transmitted through the diffusion plate (14) and emitted upward in the drawing, so that illumination light with uniform brightness can be obtained within the surface of the diffusion plate (14) of the holding case (12). Become.

<4-3-2. Image display device>
When the light emitting device of the present invention is used as a light source of an image display device, the specific configuration of the image display device is not limited, but it is preferably used together with a color filter. For example, when the image display device is a color image display device using color liquid crystal display elements, the light emitting device is used as a backlight, a light shutter using liquid crystal, and a color filter having red, green, and blue pixels; By combining these, an image display device can be formed.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
(Measurement methods for various physical properties)
<Luminescence intensity and luminance>
The emission spectrum was measured using a fluorescence measuring apparatus (manufactured by JASCO Corporation) equipped with a 150 W xenon lamp as an excitation light source and a multi-channel CCD detector C7041 (manufactured by Hamamatsu Photonics) as a spectrum measuring apparatus. The light from the excitation light source was passed through a diffraction grating spectrometer having a focal length of 10 cm, and only the excitation light having a wavelength of 455 nm was irradiated to the phosphor through the optical fiber. The light generated from the phosphor by the irradiation of the excitation light is dispersed by a diffraction grating spectroscope having a focal length of 25 cm, the emission intensity of each wavelength is measured by a spectrum measuring device in a wavelength range of 300 nm to 800 nm, and a personal computer is used. An emission spectrum was obtained through signal processing such as sensitivity correction. During the measurement, the slit width of the light-receiving side spectroscope was set to 1 nm and the measurement was performed.
The emission peak intensity and brightness were determined from the obtained emission spectrum.

<O / N ratio of phosphor surface>
The sample (phosphor) was measured using a Quantum 2000 manufactured by PHI under the following measurement conditions.
-X-ray source: Monochromatic Al-Kα, output 16 kV-34 W (X-ray generation area 170 μmφ)
・ Charge neutralization: Electron gun 2μA, combined use with ion gun
・ Spectroscopic system: Path energy
187.85 eV = wide spectrum
58.7 eV = Narrow spectrum [C1s, Eu3d3 / 2]
29.35 eV = Narrow spectrum [N1s, O1s, Si2p, Sr3d] Measurement area: 300 μmφ
・ Extraction angle: 45 ° (from the surface)

<Afterglow characteristics>
Light emission from the phosphor after irradiation with excitation light having a wavelength of 254 nm was applied to the phosphor sample under the conditions of a temperature of 25 ° C. and a humidity of 40% using a fluorescence spectrophotometer F-4500 manufactured by Hitachi, Ltd. The intensity (the monitor wavelength was the emission peak wavelength of each phosphor) was measured under the conditions of a time constant of 0.01 seconds and a measurement interval of 0.005 seconds.
Here, with respect to the phosphor of Comparative Example 1 described later, the change in afterglow characteristics was measured when the excitation light irradiation time was 30 seconds, 1 minute, 5 minutes, and 10 minutes, and the afterglow time was excited. The time that does not depend on the light irradiation time was confirmed. The irradiation time for the phosphor represented by the formula [I] was judged to be sufficient for 1 minute, and the irradiation time in the afterglow characteristic evaluation in Examples and Comparative Examples was 1 minute.

<Spin concentration>
About 300 mg of the sample (phosphor), FA300 manufactured by JEOL was used, and measurement was performed in air at room temperature under the following measurement conditions.
High magnetic field range / central magnetic field: 250 mT
-Sweep magnetic field width: ± 250mT
Magnetic field modulation: 100 kHz
・ Response: 0.1 sec
・ Magnetic field sweep time: 15 min
・ Microwave output: 0.1 mW
Narrow magnetic field range, central magnetic field: 323mT
・ Sweep magnetic field width: ± 10mT
Magnetic field modulation: 100 kHz
・ Response: 0.1 sec
・ Magnetic field sweep time: 2 min
・ Microwave output: 0.1 mW

The sample was filled in a quartz sample tube having a diameter of 5 mm. In addition, as a standard sample for radical determination, 2,2,6,6-tetramethylpiperidine-1-oxyl dispersed in a polystyrene matrix is used, and Mn ²⁺ is used for correction of g value and magnetic field width. did.
The spin concentration was determined by dividing the number of spins thus measured by the sample mass used for the measurement.

(Comparative Example 1)
Sr ₂ N is a known Sr metal (manufactured by Aldrich) described in non-patent literature (Brese, Nathaniel E. O'Keeffe, Michael, Journal of Solid State Chemistry, Volume 87, Issue 1, p. 134-140). It was manufactured according to the method.

Sr ₂ N and Si ₃ N obtained from the Sr metal so that the composition ratio of the phosphor obtained is Eu: Sr: Si: N = 0.02: 1.98: 5: 8 (molar ratio). ₄ (manufactured by Ube Industries Co., Ltd.) and Eu ₂ O ₃ (manufactured by Shin-Etsu Chemical Co., Ltd.) were weighed in a glove box filled with a nitrogen atmosphere and mixed until uniform on an alumina mortar. The obtained phosphor raw material mixture was filled in a boron nitride crucible. This was heated to 1600 ° C. under a pressure of 0.92 MPa, held at that temperature for 2 hours, further heated to 1800 ° C., held at that temperature for 2 hours, and then allowed to cool. The obtained fired product was pulverized in an alumina mortar and then sieved to obtain particles of 50 μm or less.

The phosphor was measured for emission intensity and emission luminance. Further, the surface O / N ratio by the XPS method was measured one month after the phosphor production, which seems to be sufficient to form a natural oxide film on the phosphor surface at room temperature and in the atmosphere. The results are shown in Table 9. The 1/1000 afterglow time was 8.0 seconds. The result of measuring afterglow characteristics is shown in FIG.
Further, in order to wash impurities adhering to the surface of the phosphor, the phosphor was stirred and washed with 1N hydrochloric acid at room temperature for 30 minutes and allowed to stand for 30 minutes, and then the precipitated phosphor was filtered. Thereafter, the filtered phosphor was washed 5 times with water, filtered, and finally dried in an oven at 120 ° C. for 3 hours.

Also for this phosphor, when the emission intensity, emission luminance, and surface O / N ratio by XPS method were measured, the O / N ratio on the phosphor surface was as small as 1.1, although there was no change in the emission intensity and luminance. It was. The Sr content on the phosphor surface was 6.5 atomic%.
Furthermore, when the spin concentration of this phosphor was measured, it was found to be 5.0 × 10 ⁻⁹ mol / g.

(Comparative Example 2)
The phosphor before the acid cleaning of Comparative Example 1 is filled in an alumina container, heated in the atmosphere at a temperature rising rate of 5 ° C./min, and heat-treated (refired) at 300 ° C. (maximum temperature reached) for 2 hours. And allowed to cool to room temperature.
With respect to this phosphor, emission intensity, emission luminance, and surface O / N ratio by XPS method were measured. The results are shown in Table 9. Here, the light emission intensity and the light emission luminance are shown as relative values when each value of the phosphor of Comparative Example 1 is 1. The 1/1000 afterglow time was 6.6 seconds. The result of measuring afterglow characteristics is shown in FIG.

Example 1
The phosphor before the acid cleaning of Comparative Example 1 is filled in an alumina container, heated in the atmosphere at a heating rate of 5 ° C./min, and heated (refired) at 400 ° C. (maximum temperature reached) for 2 hours. And allowed to cool to room temperature.
With respect to this phosphor, emission intensity, emission luminance, and surface O / N ratio by XPS method were measured. The results are shown in Table 9. Here, the light emission intensity and the light emission luminance were expressed as relative values when each value of the phosphor of Comparative Example 1 was 1, and the 1/1000 afterglow time was 3.2 seconds. The result of measuring afterglow characteristics is shown in FIG.

(Example 2)
The phosphor after acid cleaning of Comparative Example 1 was filled in an alumina container, heated in the atmosphere at a temperature rising rate of 5 ° C./min, and heated (annealed) at 400 ° C. (maximum temperature reached) for 2 hours. Allowed to cool to room temperature.
With respect to this phosphor, emission intensity, emission luminance, and surface O / N ratio by XPS method were measured. The results are shown in Table 9. Here, the light emission intensity and the light emission luminance are shown as relative values when each value of the phosphor of Comparative Example 1 is 1, and the 1/1000 afterglow time was 0.19 seconds. The result of measuring afterglow characteristics is shown in FIG.

Further, the amount of Sr on the phosphor surface is 12.1 atomic%, which indicates that the amount of Sr on the surface is increased as compared with the phosphor after acid cleaning in Comparative Example 1.
Further, when the spin concentration of this phosphor was measured, it was 3.2 × 10 ⁻⁹ mol / g, and it was found that the spin density was lowered.

(Example 3)
A phosphor was obtained in the same manner as in Example 2 except that the re-firing atmosphere was changed from air to nitrogen gas.
With respect to this phosphor, emission intensity, emission luminance, and surface O / N ratio by XPS method were measured. The results are shown in Table 9. Here, the light emission intensity and the light emission luminance were shown as relative values when each value of the phosphor of Comparative Example 1 was 1, and the 1/1000 afterglow time was 1.7 seconds. The result of measuring afterglow characteristics is shown in FIG.

＜ＬＥＤ耐久性＞
上記比較例及び実施例で得た蛍光体をそれぞれ用いて、発光装置を作成し、発光装置のＣＩＥ色度座標値維持率を測定した。

<LED durability>
Using each of the phosphors obtained in the comparative examples and examples, a light emitting device was prepared, and the CIE chromaticity coordinate value maintenance rate of the light emitting device was measured.

Specifically, an LED chip “GU35R460T” (light emission wavelength: 455.1 nm to 457.5 nm) manufactured by Showa Denko was bonded to an SMD LED package “TY-SMD1202B” manufactured by Toyo Denpa.
Silicone resin “SCR-1011” manufactured by Shin-Etsu Chemical Co., Ltd. and a curing agent are mixed at a ratio of 100 parts by weight: 100 parts by weight, and 6 parts by weight of the phosphor obtained in each example is added to 100 parts by weight of the mixture. The mixture was kneaded for 3 minutes with an agitator “AR-100” manufactured by Sinky Co. to obtain a phosphor-containing composition.

This phosphor-containing composition was filled to the uppermost surface of the package with the LED chip, and cured by heating at 70 ° C. for 1 hour and then at 150 ° C. for 5 hours.
The obtained light-emitting device was driven at 20 mA at room temperature (about 25 ° C.), and CIE chromaticity coordinate values (CIEx, CIEy) were measured.
Next, the CIE chromaticity coordinate values (CIEx, CIEy) were applied to the light emitting device after energization for 50, 150, 200, 250, 500, 750, and 1000 hours at 20 mA under high temperature and high humidity conditions of 85 ° C. and 85% humidity. ) Was measured, and each ratio (maintenance rate:%) with respect to the CIE chromaticity coordinate values (CIEx, CIEy) was calculated. The results are shown in Table 10 and shown in FIGS.

以上の結果から、特定温度で再焼成を行うことにより、蛍光体表面のＯ／Ｎ比が大きくなり、ＣＩＥ色度座標値（ＣＩＥｘ，ＣＩＥｙ）の維持率が向上し、耐久性が向上していることがわかる。

From the above results, re-firing at a specific temperature increases the O / N ratio of the phosphor surface, improves the maintenance rate of CIE chromaticity coordinate values (CIEx, CIEy), and improves durability. I understand that.

  It can also be seen that when the acid cleaning process is combined, the effect is further enhanced by the influence of the removal of surface impurities and the like.

  The present invention can be used in any field where light is used. For example, in addition to indoor and outdoor lighting, the present invention can be applied to image display devices for various electronic devices such as mobile phones, household appliances, and outdoor displays. It can be used suitably.

1 Phosphor-containing part (second light emitter)
2 Excitation light source (first light emitter) (LD)
3 Substrate 4 Light-emitting device 5 Mount lead 6 Inner lead 7 Excitation light source (first light emitter)
8 Phosphor-containing part (second light emitter)
DESCRIPTION OF SYMBOLS 9 Conductive wire 10 Mold member 11 Surface emitting illumination device 12 Holding case 13 Light emitting device 14 Diffusion plate 22 Excitation light source (1st light emission body)
23 Phosphor-containing part (second light emitter)
24 frames
25 Conductive wire
26, 27 electrodes

Claims (3)

A method for producing a phosphor containing a crystal phase represented by the formula [I] by firing a phosphor material, wherein the fired product is refired at a temperature of 350 ° C. or more and 500 ° C. or less after the firing step. And a process for producing a phosphor characterized by comprising the steps of:
M _2-2x Eu _2x Si ₅ N ₈ [I]
(In the formula [I], M represents an alkaline earth metal element containing at least Sr,
x represents a numerical value in a range represented by 0 <x <1. ) The manufacturing method according to claim 1 , wherein the firing atmosphere at the time of re-firing is an oxygen-containing atmosphere. After the firing step, the manufacturing method according to claim 1 or 2, the fired product before re firing process is characterized by having a step of washing with an acidic liquid medium.

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