Improving Lighting Performance of High Color Temperature White LED Packages Using (La,Ce,Tb) PO4:Ce:Tb Phosphor

Thi Phuong Thao Nguyen,Doan Quoc Anh Nguyen,Van Tho Le,Miroslav Voznak

doi:10.25073/jaec.201712.81

Abstract

Enhancement of the color uniformity, the lumen output of the multi-chip white LED lamps (MCW-LEDs) at high color correlated temperature is a big challenge for researchers. However, an innovative LED lamp designed with a phosphor compounding, which combines (La,Ce,Tb) PO4:Ce:Tb (LaTb) green phosphor with YAG: CE yellow phosphor, is proposed as an optimal solution to this requirement. Index, using LaTb green phosphor into MCWLEDs could bring a superior optical performance for MCW-LEDs. It is found that the lumen output of this new MCW-LED at a high color temperature of 8500 K significantly improves up to 1600 lm compared to MCW-LEDs without LaTb phosphor. The simulation results demonstrated that the CCT deviation sharply decreases from 9000 to 1000 at the LaTb concentration range from 0 to 1.8 %, while the Color Rendering Index ability (CRI) and the Color Quality Scale (CQS) slightly decrease. To obtain the highest lumen output and the best color uniformity, the particle size range within 6 - 8 µm should be suggested. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Highlights

White Light Emitting Diodes (WLEDs) with a potential exibility and dominant functions is becoming an important role in our life in illumination applications such as general lighting, medical, lifestyle products [1]
The above approaches are expected to improve the performance of MCW-LEDs, the luminous eciency and the angular color uniformity of white LEDs are not fully satised many dierent illumination applications, as well as extensive demands in the commercial, LED lighting market
From the obtained simulation results, we discovered that LaTb green phosphor does improve the luminescent properties in traditional uorescent lamps at such high temperature as published in a previous paper [10] and it could produce the great enhancement for color uniformity and lumen output in in-cup phosphor package of the MCW-LEDs

Summary

Introduction

White Light Emitting Diodes (WLEDs) with a potential exibility and dominant functions is becoming an important role in our life in illumination applications such as general lighting, medical, lifestyle products [1]. We propose adding LaTb green luminescent phosphor to yellow YAG:Ce phosphor compound of the MCW-LEDs to optimize its light extraction, the CCT uniformity and CRI at high color correlated temperature.

Results

Conclusion