Tactile Device Based on Piezoelectric MEMS 2^nd Report: Structural Improvements

Abstract

Tactile devices that provide touch sensation to humans by direct contact have been realized. A tactile device based on a piezoelectric MEMS is improved in this study. The driving voltage is lowered by using multilayer lead zirconate titanate (PZT) thin film. The lower voltage is experimentally validated by measuring the cantilever displacement in the device. The displacement per voltage becomes four times larger by using four layers of PZT thin film. In addition, the polymer supporting material is also investigated to reduce the temperature dependence of the device. By using polyimide as an alternative to conventional SU-8, not only the initial warpage but also the temperature dependence is dramatically improved. The driving test of the polyimide device reveals cantilever displacement comparable to that in conventional devices. In conclusion, structural improvements resulted in low-voltage actuation and reduced warpage of the piezoelectric MEMS tactile device.