Micro-Chip Shaping for Luminance Enhancement of GaN Micro-Light-Emitting Diodes Array

Significant luminance enhancement of GaN microlight-emitting diode (μLED) array was achieved by micro-chip shaping (μCS) technique. The μCSs with a shaped angle of 70° and an etched depth of 1 μm on the sidewall of μLEDs with 10-, 16-, and 50-μm pixel sizes, respectively, refract light rays through sidewalls into the light extraction cone and consequently improve the luminance. The μCSs enhance more luminance on μLED with small sizes. The maximum efficiency improvement on the μCS μLED array is over 45% compared with the vertical sidewall μLED array. Furthermore, the efficiency improvement exceeds 48% measured within ±15° extraction cone. The raytracing simulation also confirms the μCS effect.