US Patent 7620197 Casing of condenser microphone

The casing of a condenser microphone in accordance with the present invention comprises a groove at a bottom surface of the casing along an outer circumference of the bottom surface for preventing a deformation of a component during a curling process of an open end portion of the casing, wherein the casing for housing the component therein consists of a metallic material, the casing having an acoustic hole at the bottom surface thereof, the open end portion of the casing being at an opposite side of the bottom surface.