A novel acceleration switch with hat-like contact separated from proof mass

The device described in this paper is a threshold acceleration switch which has been designed and fabricated base on bulk micromachining technology. It mainly consists of four parts: A suspended proof mass serves as the moveable electrode, which sense the acceleration loaded; two symmetrical “L-shape” beams provide the function of latching, which is easy to latch and hard to release; the center contact, which is the latch point; the top anchor is to make the contact more reliable, what´s more, the cylinder contact can help improve the bad contacting effect due to imperfect fabrication. The packaged switches were tested by the drop table system. The measured minimum response shock is 3600g and the latching shock is 4800g and the response time is about 0.1 ms. The insulation resistance is more than 200M ohms and the on-state resistance is no more than 3.5 ohms.