Hermetically sealed condenser microphone

摘要

A hermetically sealed condenser microphone including an outer sealing diaphragm hermetically sealing an electroacoustic transducer within a case from the outside environment. The sealing diaphragm passes sound undiminished through an underlying intervening air space to a second active diaphragm of the electroacoustic transducer. Specifically, the case has a hollow interior, a sealed end and an open end. The electroacoustic transducer is disposed within the hollow interior of the case, and the sealing diaphragm disposed over the top of the open end of the case such that the hollow interior of the case is completely sealed. An acoustic signal first impinges upon the sealing diaphragm causing deflections therein which in turn recreate the acoustic signal undiminished in the air space within the case between the sealing diaphragm and the active diaphragm. The recreated acoustic signal then impinges on the active diaphragm of the electroacoustic transducer causing deflections therein that are converted to an electrical signal outputable from the microphone. Thus, the sealing diaphragm prevents water vapor and other contaminants from coming into contact with the internal components of the microphone, while still allowing the acoustic signal to reach the active diaphragm.