68.1: Angular Uniform White Light‐Emitting Diodes with an Internal Reflector Cup

We report on a white light-emitting diode (LED) with a truncated- conical (TC) geometry produced by laser micromachining. A blue LED was shaped into a circular disc with 50o-inclined sidewall using a modified laser micromachining setup. A layer of Al was coated onto the inclined sidewall and the bottom surface to form an integrated reflector. Due to the highly reflective mirror, laterally propagating photons were redirected into the upward direction, contributing to a 21.7 % increase of light intensity in the normal direction. with quantum dots applied to the surface, white light emission from this TC-LED structure demonstrated a 37% enhancement in color uniformity, compared with a conventional device.