Developing a Frequency-selective Piezoelectric Acoustic Sensor Sensitive to the Audible Frequency Range of Rodents

We have developed a piezoelectric acoustic sensor that responds to rodents' audible frequency range as a front-end device for a small hearing prosthesis system appropriate for animal experiments. The proposed piezoelectric transducer uses a biomimetic hearing mechanism that mimics bandpass-filtering functions realized biologically in the cochlear membranes and hair cells of rodents via a frequency-selective piezoelectric cantilever beam array that will be used to stimulate auditory neurons in future applications to humans. First, to examine the frequency selectivity and response sensitivity, a piezoelectric acoustic transducer having a cantilever array structure with multiple beams were designed, and the mechanical resonance properties of the sensor-device structure were analyzed using a numerical calculation method. Next, on the basis of the numerical results, we proposed a practical acoustic sensor design and sensor construction method using a multiple cantilever array structure and piezoelectric material. We built the sensor using standard microfabrication techniques and evaluated its piezoelectric properties in terms of sound sensitivity. Finally, we addressed future applications of an integrated system containing the proposed acoustic sensor, which could be combined with an electrical stimulation system and used as an auditory prosthesis system to compensate hearing losses in rodent models with hearing disorders and diseases. (c) 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.