US Patent 7539324 Loudspeaker diaphragm systems

A loudspeaker diaphragm includes a continuous coating on at least one surface of the diaphragm. The continuous coating may be non-uniform and may taper from a maximum in value in a conical region of the diaphragm to a minimum value in a cylindrical region of the diaphragm. The coating is formed in a single coating step without the need for use of a contact mask or interruption of the process to change process parameters. The tapered coating is formed by controlling the current density distribution within an electrochemical cell such that the rate of formation of the coating tapers from a first value in the conical region of the diaphragm to a second value is the cylindrical region of the diaphragm.