Highly Sensitive Detection of Fine Electrostatic Attraction by Resonance-Driven Silicon-Hair

This paper reports highly sensitive detection of fine electrostatic attraction using resonance-driven silicon-hair device. The device in this study is reproducing highly sensitive hair follicle to acquire peculiar sense in hairy skin of human. The device has a fine silicon-hair with 10 μm width and 5 mm length, and it independently detects 2-axis force and 1-axis moment applied to itself. The fine silicon-hair is vibrated at its resonant frequency by an external piezoelectric driver. Electrostatic attraction works to the fine silicon-hair, and the resonance frequency of vibration is affected and detected using the highly sensitive 1-axis moment detector. The 2-axis force detectors are used to monitor the operation condition of device. In the experiments, the minimum sensitivity of electrostatic attraction have reached to 0.1μN range. Resolution of force and moment detectors have been improved by tenfold using the resonance-drive of silicon-hair.