MEMS device with increased robustness and resilience to acoustic shock

摘要

The MEMS transducer structure has a flexible membrane 101 supported between a first volume 109 and a second volume 110. The transducer structure comprises at least one variable vent structure 401 in communication with at least one of said first and second volumes, said variable vent structure comprising at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent 401 may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalisation of the air volumes above and below the membrane. A number of different vent types are described (figs 7-13).