Electrostatic torsional vertical flaps for reflective MEMS display

A new kind of high contrast, MEMS-based reflective display system is being developed. The system consists of light reflective flaps on an optically absorptive surface. The novelty is that the flaps are in vertical position at their rest state. They can be electrostatically turned to horizontal state. A trench refilling technique on a silicon-on-insulator (SOI) wafer is used to fabricate the torsional polysilicon flaps. Low voltage and low power is required for actuation. With the same process also novel shutter and flap structures can be fabricated.