Surface microstructure parameter optimisation for enhancing light extraction efficiency of LED

Surface structure modification is an effective way to enhance light extraction of LED, which is limited by total internal reflection on the interfacial surface. The periodic surface structure manufactured by micromachining was proved to be a feasible way to enhance the light extraction efficiency (LEE) of LEDs. In order to obtain the highest LEE, need to optimise the structural parameters. In this paper, a simplified ray tracing optical model was built to find out a high performance microstructure parameters by simulation. Then, a mathematical model was built to further optimise the optical simulation results, obtained the optimal microstructure parameters for LEE. The performance of optimal microstructure was also studied by optical simulation.