The new TDK piezo actuator/sensor, called PowerHap™, uses voltage to create displacement when providing haptic sensations. But it can also be used in reverse to use mechanical motion to create voltage, which can be used to trigger the haptic feedback (sensor mode).
The series is offered in three sizes: 15G, 7G and 2.5G (referring to the acceleration it can deliver on a mass of 100 g). It uses an innovative multi-layer design that creates the highest acceleration and force on the market today and allows for (relatively) low voltage operation. The slim square plate consists of 23 layers with displacement amplifiers on both sides. Applying voltage creates a small expansion of the piezo ceramic in the z (out-of-plane) direction - around 1.5 microns. But the voltage also creates an even larger contraction of the plate in the x and y directions that varies from 4 to 6 to 13 microns depending on the actuator size.
Note that these actuators can require up to 120 volts - not exactly typical CMOS levels. To date, this has been a big problem with existing drivers which consume a fair amount of power. To solve this problem, Boréas Technologies has developed a new driver architecture that departs from the audio-centric designs of the past to offer a step change in performance and power consumption. Boréas Technologies CEO Simon Chaput noted that, "Our new driver offers 6X faster response time (<1ms) and 10X lower power consumption compared to existing solutions. This makes it ideal for any mobile application."