A Single-Layer Multiple Degree-Of-Freedom PDMS-On-Silicon Dynamic Focus Micro-Lens

This paper reports on a dynamic focus micro-lens capable of multiple degree-of-freedom motions. The whole device structure incorporates a SU-8 micro-lens, a three-dimensional (3-D) polydimethylsiloxane (PDMS) microstructure, and single-layer of silicon microactuators. The device fabrication is based on our previously developed fabrication method named “ Soft-Lithographic Lift-Off and Grafting (SLLOG).” The SLLOG process allows soft lithographically molded PDMS microstructures to be integrated together with silicon micromachined device patterns. The SU-8 photoresist is then formed in a lens shape on the top surface of PDMS microstructure by surface tension-driven self-formation. The developed PDMS/silicon hybrid device translates the in-plane motion of silicon comb drives into five-degree-of-freedom dynamic focus motion with fast response by taking advantage of the mechanical compliance of PDMS structures. The multiple degree-of-freedom and simple structure design may lead to high-yield high-performance dynamic focus micro-lens technology.