Patent ID: 6671383
Filing Date: 2003-12-30
Classification: H04R

Abstract:
An electromagnetic transducer comprising:a first diaphragm disposed in a vibratile manner; a second diaphragm in a central portion of the first diaphragm and formed of a magnetic material; a yoke disposed in a position opposing the first diaphragm; a center pole on a face of the yoke that opposes the first diaphragm; a coil substantially surrounding the center pole; a magnet substantially surrounding the coil; and a thin magnetic plate between the magnet and the first diaphragm and having: (a) an outer peripheral edge, and (b) an inner periphery in overlapping relation to an outer periphery of the second diaphragm, wherein the outer peripheral edge of the thin magnetic plate substantially coincides with a neutral point at which directions of magnetic flux vectors occurring on a surface of the magnet become diversified so that some of the magnetic flux vectors traverse toward the center pole while others traverse toward an outer periphery of the magnet.