Advanced microlens origination by thermal reflow

Microlenses, and especially microlens arrays (MLA), are commonly used as stand-alone optical components, for beam homogenization and shaping. Or integrated as wafer-level optics (WLO), either on top of light sources for beam shaping, or on top of light or image sensors as light concentrators. Many techniques are available to originate the microlens shape: laser ablation, grayscale lithography, two photon absorption, etc. One common way is to pattern photoresist pillars by photolithography and to melt (reflow) them. We report new advances in thermal reflow mastering addressing its intrinsic limitations and expanding the design capabilities of reflow-based MLAs.