In this paper, a new microsafing sensor is introduced for automotive applications with excellent characteristics based on silicon micromachining techniques to prevent malfunctions in air bag systems using an acceleration switch. This sensor is composed of an upper electrode, cantilever, and pedestal formed by silicon micromachining. The upper electrode and cantilever contact mechanically when acceleration during collision is applied and the "ON" signal is output. An optimal shape design is developed using finite element method (FEM) simulation to achieve a satisfactory result. The frequency characteristic of 100 Hz and threshold acceleration of 2-4 (G) are obtained by electrostatic force and chattering measure at the contact point. Other characteristics include high-speed response, compactness, and the fact that it is inexpensive, making it highly suitable as a safing sensor for side air bag systems. (A)
Abstract