Micro-cantilever shocking-acceleration switches with threshold adjusting and 'on'-state latching functions

A micromechanical shocking-acceleration switch is developed. By using electrostatic force combined with the dynamic shocking force, the switch features a threshold adjustable capability. Besides, an electrostatic pull-in phenomenon is used to enable the switch an 'on'-state latching ability. The former facilitates individual applications and can compensate for the threshold inaccuracy from fabrication tolerance. The latter can keep the switch at the 'on'-state even after the shock disappears. Theoretical analysis is carried out for the step shocking response, with the response frequency bandwidth taken into consideration. Then the switch of the 1000 - 5000 g measure range is designed, simulated with Coventor-ware and micro-fabricated using bulk micromachining technologies. Both the threshold adjusting and the 'on'-state latching functions of the micromechanical shock switch are verified by using a dropping hammer experiment. The tested data generally have an agreement with the simulated results. Even so, the slight difference between the simulation and the tested results is discussed.