Influence of phosphor packaging configurations on the optical performance of Chip on Board phosphor converted Warm White LEDs

The optical properties of high power Warm-White Light Emitting Diodes (WW-LEDs) in Chip-on-Board (COB) package of Dam-and-Fill encapsulation with three different phosphor packaging configurations were investigated in this paper. The phosphor configurations 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, differing from usual results obtained in other comparison studies of phosphor configurations in LED packages. This 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.