Formation and Integration of a Ball Lens Utilizing Two Phase Liquid Technology

This study presents a novel microlens formation technology to implement a polymer ball lens in liquid medium. The highly symmetric ball lens is achieved due to the lower gravity influence in liquid. The microlens' diameter is controlled by the volume of the dispensed polymer. Moreover, it is easy to dispense, form, and align the liquid-phase polymer microlens with MEMS structures while processing in liquid. Thus, the microlens can either be a discrete optical component, or directly integrated with MEMS structures during the process to form a SiOB (silicon-optical-bench). To date, ball lenses with diameter ranging 200mum ~ 600mum and surface roughness < 10 nm are fabricated. A typical sphericity is 8.6mum for a 525mum diameter ball lens. The integration of such polymer micro ball lens on SiOB is also demonstrated.