Enhancement of light extraction of multi-chips light-emitting diode (LED) modules with various micro-structure arrays

Low light extraction efficiency (LEE) is one of the most challenging points for light-emitting diode (LED) array packaging. Analysis of LEE enhancement of LED array packaging with micro-structures on packaging silicone is presented. To obtain high LEE, micro-structures including inversed cone, inversed frustum of a pyramid (FP) and V-groove are introduced. Two types of LED chips consisting of conventional chip (CC) and vertical thin film chip (VTFC) are conducted. Monte Carlo ray tracing simulation results demonstrate that micro-structures are able to effectively improve the LEE of LED array packaging. Among the three structures the inversed FP structures are shown to be the most efficacious in improving the LEE with enhancement of 43.18% and 31.07% for CC and VTFC respectively. This method would be a potential way in improving the LEE of LED array packaging with low profile.