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Phosphor, light-emitting device using same, image display and illuminating device

Inactive Publication Date: 2009-01-29
MITSUBISHI CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0025]In accordance with the present invention, a phosphor which can be easily produced and can provide a light emitting device having a high color rendering,

Problems solved by technology

However, there were problems that in order to produce efficiently this phosphor as a single phase, the material must be calcined at extremely high temperature that makes it difficult to produce the phosphor, and a phosphor which is uniform in emission intensity, chromaticity, particle diameter, etc. can be difficulty produced.
Also, a light emitting device comprising a blue light-emitting diode and a yellow light-emitting phosphor in combination was disadvantageous in that the emission of light in the range of from bluish green to green is short, giving deteriorated color rendering.
However, the phosphor used was disadvantageous in that it is a sulfide, can be difficulty produced and lacks stability in use.
Further, this phosphor had a high emission intensity, and it was difficult to obtain a phosphor having particle diameters which are as uniform as

Method used

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  • Phosphor, light-emitting device using same, image display and illuminating device
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  • Phosphor, light-emitting device using same, image display and illuminating device

Examples

Experimental program
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Effect test

example 1

[0086]Raw material powders were measured out such that CeO2 as M1 source compound, CaCO3 as M2 source compound and Sc2O3 as M3 source compound were incorporated in an amount of 0.01 mols, 0.99 mols and 1 mol, respectively, based on 1 mol of phosphor to give a phosphor chemical composition Ce0.01Ca0.99Sc2O4. These raw material powders were wet-ground and mixed with ethanol as a dispersion medium in a powder mixer, and the dispersion medium was then evaporated away to obtain a dried mixture of ground raw material powders. The dried ground mixture thus obtained was heated at 1,600° C. at maximum in a nitrogen atmosphere containing 4% of hydrogen in a platinum crucible for 3 hours so that it was calcined, and then subsequently subjected to washing with water, drying and classification to produce a phosphor powder.

[0087]The median diameter of the thus obtained phosphor measured by a Type LA-300 laser diffraction particle size distribution meter (produced by HORIBA, Ltd.) was 14 μm. The o...

examples 2 to 6

[0091]Phosphors were produced in the same manner as in Example 1 except that the material of the crucible and the calcining temperature during the production of the phosphor were changed as set forth in Table 1.

[0092]The phosphors thus obtained were each identified comprising CaSc2O4 as a host crystal and having trivalent Ce as an activator element in said host crystal by the analysis of powder X-ray diffraction, emission spectrum, and excitation spectrum. The emission peak wavelength and the emission intensity of the phosphors thus obtained are also set forth in Table 1. For the measurement of the emission spectrum of the phosphors of Example 2 and after, a high speed phosphor evaluation device produced by JASCO Corporation was used. This device comprises a Xe lamp as a light source and a Type C7041 multi-channel detector produced by Hamamatsu Photonics K.K. as a light-receiving element.

[0093]The phosphors produced using a platinum crucible showed a high emission intensity, and the...

examples 7 to 11

[0094]Phosphors were produced in the same manner as in Example 1 except that the formulation of mixing of raw materials Ce and Ca of phosphor were changed as set forth in Table 2. The phosphors thus obtained were each identified comprising CaSc2O4 as a host crystal and having trivalent Ce as an activator element in said host crystal by the analysis of powder X-ray diffraction, emission spectrum, and excitation spectrum. The emission peak wavelength and the emission intensity of the phosphors thus obtained are also set forth in Table 2. The phosphors obtained by adjusting the Ce mixing molar ratio to 0.01 showed the highest emission intensity. Further, as the concentration of Ce increased, the emission peak wavelength shifted toward a longer wavelength and a higher color purity green emission was shown.

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Abstract

The present invention relates to a phosphor represented by the following general formula (I), comprising: a composite oxide containing a divalent and trivalent metal elements as a host crystal; and at least Ce as an activator element in said host crystal, wherein the phosphor has a maximum emission peak in a wavelength range of from 485 nm to 555 nm in the emission spectrum at room temperature:
M1aM2bM3cOd  (I)
wherein M1 represents an activator element containing at least Ce; M2 represents a divalent metal element; M3 represents a trivalent metal element; a is a number within a range of 0.0001≦a≦0.2; b is a number within a range of 0.8≦b≦1.2; c is a number within a range of 1.6≦c≦2.4; and d is a number within a range of 3.2≦d≦4.8. Further, a light emitting device comprising said phosphor and a display and a lighting system having said light emitting device as a light source are disclosed. In accordance with the present invention, a phosphor which can be easily produced and can provide a light emitting device having a high color rendering, a light emitting device comprising the phosphor, and a display and a lighting system comprising the light emitting device as a light source can be provided.

Description

TECHNICAL FIELD[0001]In recent years, a white light-emitting device comprising in combination a gallium nitride (GaN)-based light emitting diode (LED) as a semiconductor light emitting device and a phosphor as a wavelength conversion material has been noted as a light source for display or lighting system by making the use of its characteristics of small power consumption and prolonged life.[0002]The present invention concerns a cerium (Ce)-activated oxide phosphor which can emit light in the range of from red to blue when excited with electron ray, X-ray, ultraviolet ray, visible light or the like. In particular, the present invention concerns a phosphor which can absorb light in the range of from near ultraviolet to bluish green through blue to efficiently emit light in a longer wavelength range such as from green to red through yellow, which phosphor can be used as a wavelength conversion material for absorbing light from a semiconductor light emitting device such as light-emitti...

Claims

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Application Information

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IPC IPC(8): H01J63/04H01J1/62C09K11/78
CPCC09K11/7768H05B33/14H01L33/502H01L2224/48091H01L2224/48247H01L2224/48257H01L2924/181H01L2924/00014H01L2924/00012C09K11/08H05B33/12
Inventor SHIMOMURA, YASUOKIJIMA, NAOTO
Owner MITSUBISHI CHEM CORP
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