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Sialon-based oxynitride phosphor and production method thereof

a technology of oxynitride phosphor and sialon, which is applied in the direction of luminescent compositions, discharge tubes, lighting and heating apparatus, etc., can solve the problems of not being suited light is slightly blue-tinged, and not being suitable for use as phosphor powders, etc., to achieve excellent miscibility with resin, good miscibility with resin, and little scattering

Inactive Publication Date: 2009-11-19
UBE IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides an oxynitride phosphor with improved dispersibility and fluorescent properties. By mixing and firing the raw material powder containing silicon nitride and various substances as a lithium source, a calcium source, a rare earth metal source, and an aluminum source, the ratio between the secondary particle size and the equivalent-sphere diameter calculated on the basis of the BET specific surface area is small, indicating that the powder is well dispersed. The invention also provides an oxynitride phosphor with specific particle size distribution and dispersibility that can be achieved by selecting the combination of various raw materials and the firing conditions. Only a specific combination of raw materials and firing conditions can produce a phosphor with uniform fluorescence and high emission intensity. The invention also provides a method for evaluating the dispersibility of the produced phosphor.

Problems solved by technology

However, the fluorescence wavelength of Ce-doped YAG is in the vicinity of 530 nm and when this fluorescence color and light of blue LED are mixed to produce white light, the light is slightly blue-tinged and good white color cannot be obtained.
Even when a grinding treatment is applied, only an aggregate of massive particles each resulting from firm fusion bonding of primary particles is obtained and this is not suited for use as a phosphor powder.
However, in this method, the yield of the sialon powder having a particle diameter of 2 to 20 μm is less than 55 wt %.
Moreover, the amount of Eu remaining in the particle after acid treatment is small, and excessive Eu needs to be added for obtaining a high-brightness phosphor powder.
Furthermore, there is a problem that as the particle becomes finer, the brightness of the phosphor decreases.

Method used

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  • Sialon-based oxynitride phosphor and production method thereof
  • Sialon-based oxynitride phosphor and production method thereof
  • Sialon-based oxynitride phosphor and production method thereof

Examples

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example 1

[0179]Silicon diimide (Si(NH)2) obtained by reacting silicon tetrachloride with ammonia at a temperature lower than room temperature was decomposed under heating at 700 to 1,200° C. to obtain silicon nitrogen imide (Si2N2NH) and / or amorphous silicon nitride powder. The metal impurity content of the silicon nitrogen imide (Si2N2NH) and / or amorphous silicon nitride powder was 10 ppm or less. A blend obtained by blending a compound(s) as a silicon nitride source(s) selected from nitrogen-containing silane compounds (silicon diimide (Si(NH)2) and silicon nitrogen imide (Si2N2NH)), amorphous silicon nitride and crystalline silicon nitride to give a chemical composition shown in Table 1 was used as the silicon nitride raw material. A europium oxide (Eu2O3) powder, a lithium carbonate (Li2CO3) powder and a calcium carbonate (CaCO3) powder were weighed and added to the silicon nitride raw material to give a chemical composition of Si9.25Eu0.15Ca0.62Li0.10O0.89N12.33 after firing, and these ...

example 2

[0186]An α-sialon-based oxynitride phosphor was obtained by repeating the same operation as in Example 1, except that the blending ratio of the compound(s) working as a silicon nitride source(s) selected from nitrogen-containing silane compounds (silicon diimide (Si(NH)2) and silicon nitrogen imide (Si2N2NH)), amorphous silicon nitride and crystalline silicon nitride and the firing conditions in the first and second steps were slightly changed. The conditions in the synthesis of the α-sialon-based oxynitride phosphor comprising first and second steps are shown in Table 1, and the powder properties and fluorescent properties of the obtained oxynitride phosphor are shown in Table 2.

[0187]FIG. 2 illustrates the emission spectrum at an excitation wavelength of 450 nm of the α-sialon-based oxynitride phosphor obtained in Example 2 together with the emission spectra of the α-sialon-based oxynitride phosphor obtained in Comparative Example 4 and a commercially available YAG:Ce-based fluore...

examples 3 to 15

[0188]Similarly to Example 1, those obtained by blending a compound(s) working as a silicon nitride source(s) selected from nitrogen-containing silane compounds (silicon diimide (Si(NH)2) and silicon nitrogen imide (Si2N2NH)), amorphous silicon nitride and crystalline silicon nitride to give a chemical composition shown in Table 1 were used as the silicon nitride raw material. A europium oxide (Eu2O3) powder and a lithium oxide precursor powder were weighed and added to the silicon nitride raw material to give a chemical composition of Si12−(m+n)EuyLix′O0.5x′+1.5y−δN16−4(m+n) / 3 (wherein 0≦δ≦0.5y), and these were mixed by a vibration mill under the conditions shown in Table 1 in a nitrogen atmosphere.

[0189]The mixed powder was filled in a silicon nitride-made crucible, the crucible was set in an electric furnace of resistance heating system, and the furnace was heated in a nitrogen gas atmosphere by a temperature-rising schedule of holding the furnace at from temperature to 1,150° C....

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Abstract

The present invention relates to an oxynitride phosphor comprising an α-sialon as the main component, which is represented by the general formula: MxSi12−(m+n)Al(m+n)OnN16−n:Lny (wherein 0.3≦x+y<1.5, 0<y<0.7, 0.3≦m<4.5, 0<n<2.25, and assuming that the atomic valence of the metal M is a and the atomic valence of the lanthanide metal Ln is b, m=ax+by) and in which the aggregation index, A1=D50 / DBET≦3.0 or the aggregation index A2=D50 / Dparticle≦3.0; and a production method and usage of the phosphor.The phosphor of the present invention has less aggregation and a narrow particle size distribution, and therefore is easy to uniformly mix with a resin or the like, and a high-brightness white LED can be easily obtained.D50 [μm]: The median diameter in the grain size distribution curve.DBET [μm]: The equivalent-sphere diameter calculated on the basis of a BET specific surface area.Dparticle [μm]: The primary particle diameter measured by the image analysis of a scanning electron micrograph.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2006-185134, filed on Jul. 5, 2006, the contents of which are incorporated herein by reference.TECHNICAL FIELD[0002]The present invention relates to an optical functional material having a function of converting a part of irradiation light into light at a wavelength different from that of the irradiation light and at the same time, mixing the converted light with the unconverted irradiation light to cause conversion into light differing in the color, and a production method thereof. More specifically, the present invention relates to a rare earth metal element-activated sialon-based oxynitride phosphor used for a white light-emitting diode (white LED) using a blue light-emitting diode (blue LED) as a light source. The present invention also relates to a production method of a sialon-based oxynitride phosphor for the above-described white...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): F21V9/16C09K11/77C09K11/08C09K11/64C09K11/80H01J1/63H01L33/50
CPCC04B35/597H01L33/502C04B35/62675C04B35/62685C04B2235/3203C04B2235/3208C04B2235/3217C04B2235/3224C04B2235/3852C04B2235/3865C04B2235/3873C04B2235/3895C04B2235/44C04B2235/442C04B2235/5296C04B2235/5409C04B2235/5436C04B2235/5481C04B2235/80C09K11/0883C09K11/7734H01J2211/42C04B35/6261H01L2924/181H01L2224/48091H01L2224/48247H01L2224/45144C09K11/77348H01L2924/00012H01L2924/00014H01L2924/00H01L33/50
Inventor YAMAO, TAKESHIYAMADA, TETSUOSAKATA, SHIN-ICHI
Owner UBE IND LTD
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