A novel micromachined loudspeaker topology

A novel topology for a micromachined acoustic speaker suitable for cellular phones is proposed in this paper. The membrane is composed of two materials, each of them with different function: a silicon moving part acting as a rigid piston, and polymer annulus acting only as suspension. The high ratio between Young moduli and masses of membrane and suspension leads to a simpler design of the mass-spring-damper system. This new topology can be obtained thanks to a new micromachining technology, that leads to an higher adhesion between polymer and silicon. Simulations presenting the main micro-loudspeaker parameters (e.g. SPL, frequency response) are presented in details as also the principal technological steps.