Patent ID: 8045734

Claim:
A microphone sensing element without a dedicated backplate component, comprising: (a) a substrate having front and back sides with a back hole formed therein; (b) a dielectric spacer layer with a first thickness formed on the front side of the substrate; (c) a diaphragm with a second thickness that is aligned above said back hole; (d) a plurality of perforated plates with a second thickness adjoining said diaphragm, said perforated plates and diaphragm are suspended above an air gap having a first thickness that overlies the substrate; (e) a plurality of rigid pads with a second thickness formed on said dielectric spacer layer; (f) a plurality of mechanical springs attached to said diaphragm wherein each mechanical spring has a second thickness and two ends in which one end is attached to said diaphragm and a second end is connected to one of said rigid pads; and (g) a first electrode formed on one or more of said rigid pads and one or more second electrodes formed on the substrate wherein a first electrode and a second electrode establish a variable capacitor circuit when said diaphragm, said perforated plates, and said mechanical springs vibrate up and down in a direction perpendicular to said substrate in response to a sound signal.