Microlens Array on Flip-Chip LED Patterned With an Ultraviolet Micro-Pixelated Emitter

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 is reported. Polymer microlens arrays of high optical quality have been fabricated on the sapphire side of a flip-chip truncated-conic (TC) LED. The properties of the lenses are evaluated by optical microscopy and atomic force microscopy. The determined focal length is close to the predicted value. The effects of microlens integration on the optical properties of the LED are investigated.