Patent ID: 7116796

Claim:
Diaphragm transducer comprising a planar diaphragm having a plurality of conductors on a region of a planar surface thereof, magnets arranged on one side of said diaphragm to provide magnetic field strength through said planar diaphragm for inducing electromagnetic force acting on said conductors when current flows through said conductors, wherein said magnets are in magnetic interaction with a magnetically conducting material to conduct magnetic field strength from said magnets to said diaphragm, said magnetically conducting material is not a permanent magnet, said magnetically conducting material is configured as plates on said one side of the diaphragm between which permanent magnets are located, where one edge of each of said plates constitutes a magnetic pole, said edges of said plates are arranged only on one side of said region for providing field strength through said diaphragm with magnetic field lines substantially parallel with said region, and said conductors on said diaphragm are arranged in a pattern in relation to said magnetic field strength through said diaphragm, said relation being such that said electromagnetic force acting on said conductors is directed substantially normal to said surface of said planar diaphragm.