An acceleration switch with a robust latching mechanism and cylindrical contacts

A microelectromechanical systems acceleration latching switch with cylindrical contacts and an easy-latching/difficult-releasing (ELDR) latching mechanism is presented in this paper. The cylindrical contacts can make the switch immune to fabrication imperfections and off-axis shocks and can decrease the contact resistance as well. The ELDR latching mechanism can latch the switch reliably. Moreover, all the contacts and their support beams are separated from the proof mass so as to prevent the contacts from opening due to the impact resulting from the rebound or vibration of the proof mass once the switch is latched. The switch has been fabricated by a two-mask silicon-on-glass process and tested. The measured latching shock is over 4600 g and the response time is less than 0.2 ms. The total on-resistance is less than 3 Ω while the insulation resistance is more than 100 GΩ and the maximum allowable current is up to 130 mA.