Design and characterization of an inertial microswitch with synchronous follow-up flexible compliant electrodes capable of extending contact duration

An inertial microswitch with synchronous follow-up compliant electrodes for extending the contact duration is proposed in this paper. A flexible movable electrode and a stationary electrode in the double-stair and spring-shape structures are used for not only extending contact duration but also reducing the impact bounces. The simulated contact time can reach 350 μs under 500 g applied acceleration, which indicates there is a better contact effect than that reported elsewhere. The fabricated inertial microswitch based on surface micromachining technology was characterized by the dropping hammer system. No contact bouncing behavior can be observed under the acceleration amplitude ∼466 g and the test contact duration can reach 390 μs, longer than the microwitch with only one flexible electrode. The testing comparison of the microswitches with and without constraint structure indicates that the contact-bouncing behavior is easier to happen if without constraint structure, which indicates that the designed constraint structure can restrain the vibration of the proof mass in z-off-axis sensitive direction and effectively improve the stability of the device. The test results have an agreement with the simulated ones.