The design of microstructures for multifunctional pulse measurements

Four sets of bridge-type contact-force microstructures have been designed in a 6mm×6.5mm× 0.5mm silicon die for multifunctional pulse measurements. Two wafers are used to design sensing elements and force transmission structures separately that are bonded directly by the anodic-bonding technique. The microsensing elements are piezoresistive membrane with high sensitivity. The micro-structures with backside contact design makes only the contact membrane exposed to the environment that improves measurement-induced pollution and electrical damage problems. The device's stress-strain distribution, sensitivity, and the linearity characteristic are simulated and analyzed by the finite-element method. The results provide design constrains to the microsensing structures. The proposed contact-force micro-sensing structures, provide multiple information at single measuring point, can be used to integrate signal-prooessing unit for human pulse measurements.