本文へジャンプ

成果報告書詳細
管理番号20190000000241
タイトル*平成30年度中間年報 NEDO先導研究プログラム/エネルギー・環境新技術先導研究プログラム /単粒子解析を活用したレーザー照明用蛍光体の開発
公開日2019/5/14
報告書年度2018 - 2018
委託先名デンカ株式会社 国立研究開発法人物質・材料研究機構 国立大学法人横浜国立大学 地方独立行政法人神奈川県立産業技術総合研究所
プロジェクト番号P14004
部署名イノベーション推進部
和文要約
英文要約To obtain the luminance for laser lighting, excitation power density should be at 10?30W/mm2. For this case,thermal conductivity is one of the most important factors, which should be around10W*m-1*K-1.The luminance saturation due to large excitation density is also realistic in the excitation level. Ce3+and Eu2+ with luminescence lifetime of around 50 ns and 1μs, respectively can possibly be used.However some cases of the saturation for these ions are reported. Additional investigation should be needed.Literature survey was done for existing Ce3+ phosphors. Oxynitride and Garnet phosphors are most suitable for laser lighting because of their chemical stabilities and good temperature dependence. It is difficult find other materials emit green ~ red light suitable for this application. Experimental investigations were also performed for the phosphors used in white LED. No Ce3+ red phosphor is found among them.Single particle diagnosis approach is applied to explore novel phosphors. CaAlSiN3 and La3Si6N11 were chosen as basic structure. Li, O, Mg, Al, Sr, Y, Ba, La, Eu are used for element substitution to vary ligand fields. As the result, two novel phosphors were found; one is yellow CASN type phosphor substituted by Li and O, another is LSN type with Li, Al and Ca at the interstitial sites.By spectrum simulation, a combination of LuAG:Ce3+ and CASN type:Ce3+ is predicted to give an average color index of > 75. The powder synthesis was successfully optimized for Ce3+ (Ca,Li)(Al,Si)2(N,O)3 Ce3+ (CALSON) which is novel phosphor obtained by single crystal diagnosis. The emission spectrum, quantum efficiency and temperature stability of CALSON are preferable for the application in comparison.To measure power saturation due to high excitation density up to ~50mW/mm2, necessary specifications of laser power and focus size were quantitatively investigated. Experimental study was also performed for the single particle temperature dependence measurement. The drift of view point due to thermal expansion was successfully corrected by microscopic image sensing and automatic feedback algorism. Precise measurement system is established in the temperature range of RT~300C.
Among various phosphor plate configurations applicable to laser lighting, the phosphor ceramic plate is most promising. However there are only the reports for LuAG:Ce3+ green phosphor and YAG:Ce3+ yellow phosphor. Blue or red regions are still undeveloped.
For the first step of the phosphor plates, glass matrix sintered body containing Ce activated nitride phosphor was studied. The phosphor mixed with phosphate low-melting-point glass was sintered at 500C. Optical characteristic of the plate was similar to the original phosphor. White light emission was also obtained.
AlN was chosen for the ceramic matrix because of its low reactivity with the phosphors. By selecting sintering flux, transparency was increased. The optical properties were improved by acrylic coating on sialon phosphor.
Densification and homogenization of phosphor plate were investigated. Under 1000MPa hydrostatic pressure, very high density of 70~73% was achieved. Moreover, SiAlON plate with high density of > 98% was obtained by gas pressure sintering and hot isostatic pressing. Thermal conductivity of SiAlON phosphor plate as large as 9.4W*m-1*K-1 was achieved,which is 20 times larger than those of SiAlON resin plate.
ダウンロード成果報告書データベース(ユーザ登録必須)から、ダウンロードしてください。

▲トップに戻る