Mapping and Simultaneous Detection of Arterial and Venous Pulses using Large-Scale High-Density Flexible Piezoelectret Sensor Array

Flexible sensors with the capability of mapping and examining real-time physiological signals are essential in smart health monitoring systems. Here, high-density and large-scale flexible pressure sensor arrays with the piezoelectric-like dynamic output effects are presented for the mapping and detection of arterial and venous pulses simultaneously. A high equivalent d33 value of 5400 pC N-1 is characterized based on the crisscross groove structure of a single sensor unit with a high dynamic sensitivity of 15.22 nA kPa-1 (<5 kPa), detection limit of <5 Pa, response time of 36 ms, and good temperature-humidity-mechanical stabilities. A 3 × 3 prototype array using 4 × 4 mm2 individual sensor units is utilized to plot the pulse magnitude map in the neck region. Experimental results show that this system can differentiate independent and stable arterial and venous pulses simultaneously to acquire the comprehensive cardiac information. Another 5 × 18 prototype array using 1.5 × 0.5 mm2 individual sensor units is demonstrated to detect wrist pulses and map the vascular network successfully toward the practical applications in wearable healthcare and electronic skin systems.