US Patent 6937736 Acoustic sensor using curved piezoelectric film

An acoustic sensor device comprising a substrate having a first surface and a second surface opposite the first surface, and an aperture formed therethrough, the second surface having a curved portion; a layer of piezoelectric film having a first surface disposed on the curved portion of the substrate second surface; and a layer of pliable material disposed on a second surface of the piezoelectric film opposite the first surface for contacting with an object to be sensed.