53‐5: Late‐News Paper: High‐resolution Optical Inspection of NR LEDs‐based Assembly and Their Evaluation for Display Applications

Abstract

This study presents high‐resolution optical inspection methods to evaluate the assembly yield of densely‐aligned NR LED array for self‐emitting inorganic material‐based display. Fast line scanning images and their deep learning‐based image analysis enabled us to quantitively investigate the assembly yield of NR LEDs even up to 5300 pixel per inch in which, thereafter, automatic optical inspection (AOI) accuracy reaches up to 97 % after 8000 times iteration. Furthermore, confocal photoluminescence optical microscopic system with picoseconds time resolving capability investigated tens nanometer spatially‐resolved emission characteristics of NR LEDs while also showing the non‐radiative recombination from the damaged active layers. Therefore, we believe that this study contributes a significant step toward inspection process of micro LEDs and their manufacturing development.