Power-efficient piezoelectric haptic actuators with large deflection

Surface haptic devices based on piezoelectric actuators are one of the most promising solutions to achieve subtle touch feedback on various surfaces. In comparison to stand-alone actuators, piezoelectric thick film actuators not only have a low power consumption and a large deflection range, but also allow for direct integration on various substrates. Herein, we fabricated power-efficient haptic actuators by screen-printing 10 µm-thick platinum bottom electrode and 80 µm-thick niobium-doped lead zirconate titanate (PZT) on alumina substrate (25.5 ×12.5 mm2). Our fabricated haptic device containing two actuators (10 ×1 mm2 per actuator) connected in parallel exhibits an antisymmetric Lamb wave resonant mode at 17.8 kHz, in line with finite element modelling. At the limit of touch detection (1 µm out of plane deflection), the device consumes only 5 mW at a unipolar voltage of 20 Vpp. At a unipolar voltage of 150 Vpp, the peak-to-peak out-of-plane displacement reaches nearly 10 µm.