International Journal of Power Electronics and Drive System (IJPEDS) Vol. 8, No. 1, March 2017, pp. 125~129 ISSN: 2088-8694, DOI: 10.11591/ijpeds.v8i1.pp125-129  125 Journal homepage: http://iaesjournal.com/online/index.php/IJPEDS Using Green Emitting Phosphor for Improving Lighting Performance of In-cup Package White LED Lamps Phu Tran Tin 1 , Nguyen Huu Khanh Nhan 2 , Tran Hoang Quang Minh 3 1 Faculty of Electronics Technology, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam 2,3 Optoelectronics Research Group, Faculty of Electrical and Electronics Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam. Article Info ABSTRACT Article history: Received Sep 30, 2016 Revised Dec 06, 2016 Accepted Dec 16, 2016 LED technology had a huge development in recent years with major benefits: long-life, high-efficiency, excellent performance, compactness. In this work, an innovative method for improving the performance of multi-chip white LED lamps (MCW-LEDs) by adding the green Ce 0.67 Tb 0.33 MgAl 11 O 19 :Ce,Tb (CeTb) phosphor to their in-cup phosphor compounding is proposed, investigated and demonstrated. Firstly, CeTb was mixed to the in- cup phosphor package of MCW-LEDs. Then by varying CeTb concentration, lumen output and angular color uniformity (ACU) of MCW-LEDs was calculated and analyzed. The results showed that the lumen output and the ACU of 7000 K and 8500 K MCW-LEDs increased significantly in comparison with others related works. This method is a prospective ideal for future improving LED manufacture. Keyword: Angular color uniformity Ce 0.67 Tb 0.33 MgAl 11 O 19 :Ce,Tb Lumen output Multi-chip white LED lamps Copyright © 2017 Institute of Advanced Engineering and Science. All rights reserved. Corresponding Author: Tran Hoang Quang Minh, Optoelectronics Research Group, Faculty of Electrical and Electronics Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam. Email: tranhoangquangminh@tdt.edu.vn 1. INTRODUCTION In the near studies, the quality enhancements of MCW-LEDs such as lumen output and ACU are considered [1]. Similarly, the quality of multi-chip white LED lamps are also enhanced significantly by adding SiO2 powder to YAG:Ce phosphor compound [2]. The yellow YAG:Ce phosphor material is mixed with silicone glue to form a phosphor compounding which absorbs the blue light of the blue chips and emits the yellow light. When the white light rays, which is achieved by the mixture of the colors, walk through phosphor particles. They are scattered in the phosphor compounding. The blue light is mixed with the yellow light during this process. Because of the absorption process of the yellow YAG:Ce phosphor particles, the blue light becomes weaker. Meanwhile, the converted yellow light is intensified through each scattering. Correspondingly, the difference of light intensity distributions can cause a yellow ring phenomenon [3]. To enhance light quality and lumen output, the multiple phosphors or the optical structures of white LED lamps could be optimized. Won et al. have demonstrated the strong influence of phosphor geometry on the lumen output of LED lamps with higher color rendering index (CRI) by adding green (Ba,Sr) 2 SiO 4 :Eu 2+ and red CaAlSiN 3 :Eu 2+ phosphors with various phosphor structures to the blue LEDs [4]. Oh et al. have proposed G- A-R multi-package LED, which provides higher lumen output and good CRI [5]. Zheng et al. have enhanced the CRI of the LED lamp by using multi-chromatic phosphor [6]. The targets of these studies concentrate on improving CRI and lumen output without solving the ACU enhancement problems. Moreover, the studies only focus on single-chip white LED lamps, but it hardly really can improve the light quality of multi-chip white LED lamps having high CCTs. The green-emitting CeTb is a hexagonal poly-aluminate, which has a