Dual-Detections of Tactile Force and Proximity with an Ultra-Sensitive Integrated Microcantilever Sensor

In this work, we report a monolithically integrated piezoresistive microcantilever sensor processed by SOI CMOS and MEMS technologies. A tactile force sensor with a force resolution of 68 μN was realized by packaging the microcantilever with a polydimethylsiloxane (PDMS) elastomer. Using the ultra-high sensitivity force sensor, three characteristic peaks of wrist pulse, namely percussion wave (P-wave), tidal wave (T-wave) and diastolic wave (D-wave), were accurately distinguished. Additionally, a proximity was also detected by the tactile sensor based on a photoelectric effect above the PDMS contact interface and a force induced PDMS deformation under the contact interface, and a minimum distinguishable displacement of 0.1 μm was obtained under the force mode.