Piezoelectric resonating tactile stimulators for the stimulus enhancement achieved by reduced stiffness structures with air chambers

Abstract

We have designed, fabricated and tested piezoelectric resonating actuators for tactile stimulation. The piezoelectric resonating tactile stimulators are composed of 3×4 stimulating dot arrays with air chambers. The piezoelectric resonating tactile stimulators use indirect piezoelectric actuation for tactile stimulation, by including specially designed polyimide air chambers on the piezoelectric polymer (polyvinylidene fluoride, PVDF) films. The air chambers on the PVDF films enhance stimulus by reducing the stiffness of total structure, smaller than that of the conventional direct piezoelectric actuation without air chambers. The piezoelectric resonating tactile stimulators are fabricated and characterized. The stimulators achieve the output displacement of 257.0 ± 1.5 nm, the output pressure of $339.1 N/m^2$, and the response time of 0.7 ms when the input voltage of $80 V_{pk}$ (52.5 kHz) is switched at 2 ms intervals (250 Hz), thereby 273.7 % stimulus enhancement compared to the conventional direct piezoelectric actuation. It has been experimentally demonstrated that the proposed piezoelectric resonating actuators are capable of stimulating human skin to support tactile or braille displays integrated into tactile interface systems.