Faculty Bibliography

Vertically and laterally driven MEMS inertia switches are designed. The solid modeling and finite element dynamics analysis of the Nickel micro-spring in the switch are conducted. The stress distribution and the displacement-time response curve of the micro-spring under dynamic load are obtained. The influence of configuration parameters on the spring constants (including klevel and kvertic) are compared under static and dynamic loads. The finite element dynamics analysis is considered to be a useful method in evaluating the spring constant in MEMS devices, especially for the spring in inertia micro devices working under the dynamic load.

A novel MEMS inertia micro-switch has been designed basing on non-silicon surface micromachining technology. The switch mainly consists of a thicker mass block as mobile electrode and a suspended elastic beam as fixed electrode locating above the mass block. The designed switch structure not only benefits the improvement of the sensitivity and the contact effect, but also protects the switch against shock damage owing to too much deviation of the mass block and the snake springs. The dynamics finite element contact simulation about the designed switch has been done. The results show that the response time and the contact time of the switch is about 0.24ms and 10 μs respectively when 100g acceleration was applied, which is relatively better sensitivity and contact effect. The response time of the inertia micro-switch would decrease when applied acceleration was increased, and the contact effect between two electrodes would be enhanced.

A novel design of MEMS electrical inertia micro-switch was proposed. In the design, an elastic beam with holes was used as the fixed electrode, and a suspended thicker mass block with conjoined snake springs was used as the mobile electrode locating between the supporting layer and the elastic beam. This designed switch structure benefits the improvement of the sensitivity, the contact effect, and protects the switch against intensive shock damage. The micro-switch had been fabricated using cost-effective electroplating nickel and tested subsequently. The result indicates that the response time and the contact time of the micro-switch are about 0.40 ms and 12 μs respectively when 100 g acceleration is applied, which shows relatively better sensitivity and contact effect. This result has an agreement with that of dynamics finite element contact simulation about the designed micro-switch.