A novel contact-enhanced low-g inertial switch with low-stiffness fixed electrode

A novel contact-enhanced low-g inertial switch with low-stiffness fixed electrode was designed, fabricated and tested for airbag restraint systems in this paper. Its sensitive direction is vertical of the switch. By adopting a novel low-stiffness arc structure as the fixed electrode and using Archimedean spiral beams to support center proof mass, the flexibility of the system increased and the contact duration extended. In order to restrict the radial displacement of the proof mass and keep it at the central zone of the switch, a circular limited post was installed at the center of the proof mass. The dynamic response of the switch was simulated and analyzed by ANSYS software. The simulation results indicate that the novel arc electrodes have low stiffness and the switch with this kind of new structure has long contact time. Six-layer photolithography and electroplating technology were used to fabricate the micro-switch and the overall dimension of the switch is 3850 mu m x 3850 mu m x 240 mu m. Ultimately, the fabricated prototypes were tested by dropping hammer system. The contact times of the prototypes can be up to 260 mu s under the acceleration with 26 g.