상향방 형광체 플레이트: 투명 phosphor-in-glass 제조 및 백색광 구현

Abstract

White light LED is consisted with blue LED lighting and yellow color converter phosphor-in-glass part. For automotive headlamp application, the devices require ultra-high brightness. However, this bright blue light can harm human eyes because of its high energy. In this study, 980 nm NIR lighting devices are introduced for replacing blue lighting parts, and Y2O3:Er3+, Yb3+, Y2O3:Tm3+, Yb3+, and Y2O3:Er3+, Tm3+, Yb3+ up-conversion phosphor has synthesized and phosphor-in-glass containing these phosphors has manufactured. Under 980 nm excitation, Y2O3:Er3+, Yb3+ showed the weak green and strong red emission, and Y2O3:Tm3+, Yb3+ emitted blue emission with invisible NIR emission. When Yb3+ concentration has changed, red emission from Er3+ has enhanced rather than green emission from Er3+. The blue emission from Tm3+ has increased since the Yb3+ concentration reaches 5 mol%, and decreased when Yb3+ concentration is over 5 mol%. The phosphor-in-glass of each phosphor showed their unique emission under 980 nm excitation. When the plates were stacked, the emission from the phosphor-in-glass expressed the white color by mixing each emission color. As the result, the white light emitting phosphor-in-glass under NIR excitation has manufactured.|백색광 LED는 청색 LED 발광부와 황색 색변환 재료인 형광체 플레이트를 사용하여 제작된다. 그리고 차량 전조등에 사용되는 조명은 운전자의 시야를 장거리까지 확보해야 하므로 아주 강한 휘도를 요구한다. 그런데 청색광은 그 에너지가 강하므로, 차량 전조등용 LED에 사용되는 초고휘도 청색광이 안구에 직접 입사될 경우 치명적인 손상을 입힐 가능성이 존재한다. 본 연구에서는 기존 백색광 LED에서 사용되는 위험성이 큰 청색 발광부를 대체하기 위하여 980 nm 적외선 발광부를 도입하였고, 적외선 발광에 반응하는 up-conversion 형광체인 Y2O3:Er3+, Yb3+와 Y2O3:Tm3+, Yb3+를 합성하여 이를 적용한 백색광 PiG를 제작하고 up-conversion 형광 특성을 연구하였다. 합성된 형광체 분말에 980 nm의 파장을 가지는 빛이 입사되자 Y2O3:Er3+, Yb3+ 분말은 약한 565 nm의 녹색 발광과 강한 665 nm의 적색 발광을 나타냈으며, Y2O3:Tm3+, Yb3+ 분말은 490 nm의 청색 발광을 나타냈다. Y2O3:Er3+, Yb3+의 적색 발광은 형광체에 첨가된 감광제인 Yb3+의 농도에 따라 더욱 강해지는 것을 확인하였다. 위 형광체를 포함시켜 제작한 phosphor-in-glass (이하 PiG)에서도 해당 형광체 고유의 발광이 변형되지 않고 나타나는 것을 확인하였다. 각 형광체를 포함한 PiG를 적층하여 발광을 확인하였으며, 최종적으로 백색의 발광이 구현되었음을 확인하였다.; White light LED is consisted with blue LED lighting and yellow color converter phosphor-in-glass part. For automotive headlamp application, the devices require ultra-high brightness. However, this bright blue light can harm human eyes because of its high energy. In this study, 980 nm NIR lighting devices are introduced for replacing blue lighting parts, and Y2O3:Er3+, Yb3+, Y2O3:Tm3+, Yb3+, and Y2O3:Er3+, Tm3+, Yb3+ up-conversion phosphor has synthesized and phosphor-in-glass containing these phosphors has manufactured. Under 980 nm excitation, Y2O3:Er3+, Yb3+ showed the weak green and strong red emission, and Y2O3:Tm3+, Yb3+ emitted blue emission with invisible NIR emission. When Yb3+ concentration has changed, red emission from Er3+ has enhanced rather than green emission from Er3+. The blue emission from Tm3+ has increased since the Yb3+ concentration reaches 5 mol%, and decreased when Yb3+ concentration is over 5 mol%. The phosphor-in-glass of each phosphor showed their unique emission under 980 nm excitation. When the plates were stacked, the emission from the phosphor-in-glass expressed the white color by mixing each emission color. As the result, the white light emitting phosphor-in-glass under NIR excitation has manufactured.