Convex Microarrays-Based Liquid Metal Soft Piezoresistive Stress Sensor With High Sensitivity and Large Measurement Range

Liquid metal (LM) soft piezoresistive sensors, that is, devices that change resistance in response to mechanical forces, have low hysteresis and high stability, which exhibit great promise for human health monitoring. Applying stress reduces the cross-sectional area of the LM conductive path in the sensor, increasing the resistance and enabling the measurement of stress. However, increasing the sensitivity of the sensor results in a reduced measurement range and an increase in the cost. To solve this problem, this article presents a convex microarrays (CMs)-based LM soft piezoresistive stress sensor with high sensitivity and large measurement range. The CMs are located inside the microchannel, which improves the sensitivity of the sensor without reducing the measurement range. The CMs also enable the sensor to monitor bending. The mechanism of the CMs is verified by theoretical analysis, finite element simulation, and experiments. The relationship between the height of the CMs and the sensitivity is investigated. The sensor can be used in the field of human health monitoring.