COLLAPSIBLE IMAGE DERIVED DIFFERENTIAL MICROPHONE

摘要

An acoustic signal receiving apparatus comprising a housing having an acoustically reflecting surface and a directional acoustic sensor unit having first-order gradient characteristics. The sensor unit is coupled to the housing with use of a retractable member having a retracted position and an extended position. When the member is extended, the sensor unit is positioned relative to the reflecting surface such that the acoustic interaction between the sensor unit and the reflecting surface causes the output of the sensor unit to have second-order gradient response characteristics. In accordance with one illustrative embodiment, in a notebook computer with a "flip-back" lid, the sensor element automatically extends to the desired position when the lid is opened, and automatically retracts to be flush with the housing surface when the lid is closed.