Analysis of Package Factors Affecting the Light Output Efficiency of Quantum Dots-Based Micro-LEDs

As the demand for telecommuting, remote instruction, and non-contact testing increases, augmented reality (AR) and virtual reality (VR) are growing rapidly due to the ability to fulfill site constraints. The key component of AR/VR is the microsize light sources. Among various types of potential sources, light emitting diodes (micro-LEDs) are the one of the most promising candidates. Different packages have a significant impact on the light output characteristics of micro-LEDs, which in turn affects their application. In this work, Monte Carlo ray tracing method is used to study the luminous characteristics of quantum dots (QDs) based micro-LEDs in different package structures. The effects of various bank reflectance and tilt angle on the luminous characteristics are simulated to fit the different needs of practical applications. With the increase of reflectivity, the light efficiency is significantly improved, and the impact is the largest at the bank with the angle of 90°, where the light efficiency increases from 11.73% to 100%. The effect of QDs with different thickness and concentration on light efficiency was analyzed. The effect of QDs on light efficiency is not significant. However, owing to the formation of total internal reflection inside the micro-LED and the scattering characteristics of QDs, the absorption characteristics, which make the loss severe, semispherical micro-lens were added to break the total internal reflection at the light emitting interface and the light efficiency was increased by about 30%. This study will provide guidance for micro-LED packaging of different applications.