Polymeric micro-cantilever array for auditory front-end processing

A polymeric micro-cantilever array has been developed that mimics the biological front-end processing in the mammalian cochlea, and is intended for use in applications of auditory prostheses. Made of optical epoxy polymer molded over a silicon substrate, the micro-cantilevers have similar mechanical performance as the basilar membranes in the mammalian ears. The polymeric cantilevers, which are transparent, are used as optical waveguides to guide and modulate a light beam, which is initiated from a light emitting diode (LED) and collected by a photo diode, to produce a signal suitable for human hearing when the sound wave excites them. The polymeric cantilevers have Q(10) values of 9.38, 10.11, 11.56, and 14.01 for resonant frequencies at 286, 720, 2868, and 6948 Hz, respectively. These values are similar to those obtained by direct measurement of the basilar membrane. Furthermore, they have a linear dynamic range of more than 80 dB sound pressure level (SPL) with less than 15% total harmonic distortion (THD). This polymeric micro-cantilever array has low power consumption, short processing time, high sensitivity, high frequency resolution, small size, is insensitive to electromagnetic interference, and is suitable for a totally implantable device in the human ear. (C) 2003 Elsevier B.V. All rights reserved.