Oxynitride phosphor and light-emitting instrument

a technology of oxynitride and light-emitting instruments, which is applied in the direction of gas discharge electrodes, discharge tube/lamp details, solid-state devices, etc., can solve the problems of luminance drop, and achieve the effect of reducing material deterioration and luminance drop, and high luminan

Inactive Publication Date: 2007-01-25
NAT INST FOR MATERIALS SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0043] The sialon fluorescent material obtained by the fabrication process of the invention has ever higher luminance and is much more reduced in material deterioration and luminance drop even upon exposure to excitation sources, as compared with conventional sialon fluorescent materials; it lends itself well to applications such as VFDs, FEDs, PDPs, CRTs and white LEDs. Thus, the invention provides a novel yet promising material for material designs in that technical art.

Problems solved by technology

A problem with the fluorescent material is, therefore, that its luminance drops as a result of exposure to such an excitation source as mentioned above.

Method used

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  • Oxynitride phosphor and light-emitting instrument

Examples

Experimental program
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Effect test

example 1

[0100] To obtain a compound represented by compositional formula La0.2Ce0.8Si5Al2O1.5N8.7 (Table 3 shows the mixing composition of the starting powders; Table 4 parameters; and Table 5 a post-reaction calculated composition), weighing was done such that silicon nitride powders having an average particle diameter of 0.5 μm, an oxygen content of 0.93% by weight and an α-type content of 92%, aluminum nitride powders, lanthanum oxide and cerium oxide were at 48.66% by weight, 17.06% by weight, 27.12% by weight and 7.16% by weight, respectively, and a 2-hour mixing was carried out in a wet ball mill using n-hexane.

[0101] n-Hexane was evaporated off in a rotary evaporator, and the ensuing mixture was molded in a mold at a pressure of 20 MPa into a compact of 12 mm in diameter and 5 mm in thickness.

[0102] That compact was placed in a boron nitride crucible, which was then set in an electric furnace of the graphite resistance-heating mode. Firing operation was started with evacuation of a...

examples 2-12

[0111] As in Example 1, oxynitride powders were prepared with the exception that the compositions shown in Tables 3, 4 and 5 were used. As a result, high-luminance fluorescent materials excited by ultraviolet radiation were obtained as set out in “Examples 2-12” in Table 6.

[0112] In Example 3 (Ce1Si5Al2O1.5N8.7), only Ce was contained as the rare earth element, and the obtained fluorescent material emitted 468-nm blue light, with spectra shown in FIG. 3. In Example 5 (La0.8Eu0.2Si5Al2O1.5N8.7), Eu worked as a luminescence center, and the obtained fluorescent material emitted green light of 510 to 550 nm with spectra shown in FIG. 4.

[0113] In Example 8 (La0.5Tb0.5Si5Al2O1.5N8.7), Tb worked as a luminescence center, and the obtained fluorescent material emitted green light with spectra shown in FIG. 5.

examples 14-32

[0118] The starting powders used herein were silicon nitride powders (having an average particle diameter of 0.5 μm, an oxygen content of 0.93% by weight and an α-type content of 92%), aluminum nitride powders (having a specific area of 3.3 m2 / g and an oxygen content of 0.79%), lanthanum oxide powders (with a 99.9% purity), europium oxide powders (with a 99.9% purity), aluminum oxide powders (with a 99.9% purity), lanthanum nitride powders obtained by synthesis by nitriding of metallic lanthanum (with a 99.9% purity) in ammonia, cerium nitride powders obtained by synthesis by nitriding of metallic cerium in ammonia, and europium nitride powders obtained by synthesis by nitriding of metallic europium in ammonia.

[0119] These starting powders were weighed in such a way as to have compositions as shown in Table 7. The composition was mixed in a mortar with an agate pestle for 30 minutes. Then, the resulting mixture was passed through a 500-μm sieve, and allowed to fall gravitationally ...

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Abstract

The invention has for its object the provision of an oxynitride fluorescent material has higher emission luminance than conventional rare earth element-activated sialon fluorescent materials. To this end, an oxynitride fluorescent material is designed in such a way as to contain as the primary constituent a JEM phase represented by a general formula MA1(Si6−zAlz)N10−zOz wherein M is one or two or more elements selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. For instance, this fluorescent material has a fluorescent spectrum maximum emission wavelength of 420 nm to 500 nm inclusive and an excitation spectrum maximum emission excitation wavelength of 250 nm to 400 nm inclusive.

Description

ART FIELD [0001] The present invention relates generally to a silicon oxynitride fluorescent material composed primarily of a JEM phase, and its applications. More specifically, the present invention is concerned with a lighting device used alone or in combination of image displays, which harnesses the properties of that fluorescent material, that is, its ability to emit fluorescence having a wavelength of 420 nm or longer. BACKGROUND ART [0002] Fluorescent materials are used for vacuum fluorescent display tubes (VFDs), field emission displays (FEDs), plasma display panels (PDPs), cathode-ray tubes (CRTs), white light-emitting diodes (LEDs), etc. To allow the fluorescent material to emit light in any application, energy for exciting it must be supplied to it. Upon excitation by an excitation source having high energy such as vacuum ultraviolet radiation, ultraviolet radiation, electron radiation, blue light or the like, the fluorescent material gives out visible light rays. A proble...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C09K11/08C09K11/66C04B35/58C04B35/597C09K11/77C09K11/80H01J1/63H01J11/12H01J11/22H01J11/24H01J11/26H01J11/34H01J11/42H01J29/20H01L33/50H01L33/62
CPCC04B35/597C04B2235/3224H01L2224/48247C04B2235/3227C04B2235/3229C04B2235/3865C04B2235/3869C04B2235/3873C04B2235/3878C04B2235/3895C04B2235/5445C04B2235/761C04B2235/80C04B2235/9646C09K11/7774H01L33/502H01L2224/48091H01L2924/00014H01L2924/181H01L2224/73265C09K11/77748H01L2924/00012C09K11/77C04B35/58
Inventor HIROSAKI, NAOTO
Owner NAT INST FOR MATERIALS SCI
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