MEMS acceleration switch with bi-directionally tunable threshold

• We firstly propose a bi-directionally tunable MEMS acceleration switch.
• Threshold decreased from 10.25 g to 2.0 g by applying tuning voltage.
• Threshold increased from 10.25 g to 17.25 g by applying tuning voltage.
• Additional functionality of safe/armed position convertibility is realized.
• Additional functionality of mechanical latching is realized.

A MEMS acceleration switch capable of tuning threshold acceleration to either higher or lower levels is designed and implemented with comb drive actuators as a mechanism of threshold tuning. A small sized switch (1.6 × 3.1 × 0.55 mm3) is successfully realized by patterning silicon structures on a glass wafer. The resonant frequency of fabricated switches agrees well with a designed frequency of 1.1 kHz. The threshold acceleration at no tuning voltage is 10.25 g and it is subsequently tuned to 2.0 g and 17.25 g by applying 30 V to pushing comb and pulling comb, respectively. The rising time is measured to be 9.8 ms. Additional functionalities such as safe/armed position convertibility and single use latching switch are also described for diverse applications of the tunable acceleration switches.