Electret microphone

Abstract

An electret microphone is provided. This comprises an electrically conductive membrane, and a counter-electrode having at least one first hole having a first distance from an edge of the counter-electrode and a second plurality of second holes each having a second distance from the edge of the counter-electrode. The second distance is shorter than the first distance. The electret microphone has a first electrically conductive coating on a first side of the counter-electrode and a second electrically conductive coating on a second side of the counter-electrode. The at least one first hole comprises a via in order to electrically contact the first and second electrically conductive coating. A third distance is provided in each case between the second holes and the first electrically conductive coating so that the first electrically conductive coating does not reach as far as the second holes. The electret microphone further comprises a polarizable film which extends completely over the first electrically conductive coating and thereby leaves free the first and second holes, wherein the polarizable film extends as far as the second holes.

Dependencies are inferred from the claim text.