New human machine interface devices using a piezoelectric poly(L-lactic acid) film

Poly(lactic acid) (PLA) is a well-known, environmentally-friendly polymer. Piezoelectric poly(L-lactic acid) (PLLA), a type of chiral polymer, exhibits a high shear piezoelectric constant, is highly transparent, and is not pyroelectric. New human machine interface devices with intuitive control can be fabricated using piezoelectric PLLA as a deformation sensor. Specifically, for projected capacitive touch panels widely used in smartphone technology, the PLLA film as a pressure sensor with multiple electrodes allows pressure-sensitive functions to be added to the touch panel display.