Patent ID: 7888840
Filing Date: 2011-02-15
Classification: H04R

Abstract:
1. A microphone comprising: a diaphragm supported at a center thereof, and which vibrates when the diaphragm receives acoustic waves; first electrode pairs, each of the first electrode pairs having a first electrode and a second electrode; second electrode pairs, each of the second electrode pairs having a third electrode and a fourth electrode; and a controller; wherein: the first electrodes of the first electrode pairs are arranged on a surface of the diaphragm at positions distributed around the center of the diaphragm; each of the second electrodes of the first electrode pairs is arranged at a position facing a uniquely corresponding first electrode of the first electrode pairs to form a gap between each of the second electrodes of the first electrode pairs and the corresponding first electrode of the first electrode pairs, each of the first electrode pairs forming a first capacitor; the third electrodes of the second electrode pairs are arranged on a surface of the diaphragm at positions distributed around the center of the diaphragm; and each of the fourth electrodes of the second electrode pairs is arranged at a position facing a uniquely corresponding third electrode of the second electrode pairs to form a gap between each of the fourth electrodes of the second electrode pairs and the corresponding third electrode of the second electrode pairs, each of the second electrode pairs forming a second capacitor; the controller applies electric energy to each of the first capacitors and each of the second capacitors; the controller applies predetermined electric energy to each of the first capacitors; the controller detects the capacitance of each of the first capacitors; the controller applies electric energy to each of the second capacitors, and each electric energy applied to the corresponding second capacitor is independently controlled such that a detected capacitance of each first capacitor is maintained at a constant value; and the controller identifies a direction along which the acoustic wave propagates based on values of the electric energies, each electric energy being applied to each of the second capacitors.