Influence of Phosphor Packaging Configurations on the Optical Performance of Chip on Board Phosphor Converted Warm White LEDs

Peng Hui Yuen,  Hwang Hsien Hsiung,  Mutharasu Devarajan
Universiti Sains Malaysia


The optical properties of high power Warm-White Light Emitting Diodes (WW-LEDs) in Chip-on-Board (COB) package via Dam-and-Fill encapsulation with three different phosphor packaging configurations are investigated in this paper. The phosphor configurations that studied were remote phosphor, double phosphor layers and normal phosphor configuration. Analysis of experimental data shows that LED samples in COB package with normal phosphor configuration had the highest efficiency compared to the other two phosphor configurations, which is differing from usual results obtained from comparison studies of phosphor configurations in other LED packages. The investigation also shows that LED samples with remote phosphor configuration has the highest relative intensity at red-yellow emission region, while LED samples with normal phosphor configuration has the highest relative intensity at blue emission region.