LED with integrated microlens array patterned by an ultraviolet linear micro-LED array

We report on a direct-write lithographic technique for the fabrication of micro-lens arrays with an ultraviolet (UV) micro-light-emitting diode (LED) array, serving as an exposure source. Owing to the Lambertian emission distribution of LEDs, the exposed UV sensitive coating (UV epoxy) adopts the same profile, resulting in spherical lenses being formed naturally, without further reflow. Microlens arrays of high optical quality have been fabricated and integrated with a flip-chip LED. The properties of the lenses are evaluated by optical microscopy and atomic force microscope. The far field emission pattern from this microlens-integrated LED indicated that our microlens array contributed to reduction of divergence cone significantly.