Light degradation test and design of thermal performance for high-power light-emitting diodes

Abstract

Light-emitting diodes (LEDs), which are generally used for indicator lights, have been continuously developed for the past 50years. With an urgent need for energy conservation and pollution reduction, the trend of replacing traditional incandescent or fluorescent lamps with high-power LEDs is growing more and more popular. Consequently, LEDs have attracted the attention of many industries that incorporate LED researches and designs into their products. However, a low electro-optical conversion efficiency of LEDs can induce a high percentage of input power that transforms into redundant heat. This leads to an increase in the junction temperature, which indicates that thermal management is an important issue in high-power LEDs. In this research, a light degradation test is implemented and a chip-in-substrate-type LED packaging structure is proposed. A finite element (FE) model of the chip-in-substrate-type structure with an effective methodology, which is validated through the forward voltage method, is established. With regard to the design concepts of LED packaging, various parameters of chip-in-substrate-type structure are investigated.