Evaluation of sensitivity improvement for a piezoelectric-actuator-integrated artificial cochlear epithelium

Abstract

In this paper, we report the vibration control of an artificial cochlear epithelium. The device is a trapezoidal piezoelectric membrane with patterned Al electrodes. The resonance frequency of the piezoelectric membrane varies locally according to the longitudinal position, and the electric potential difference is produced by the vibration of the membrane induced by sound stimuli. In this study, we use the electrodes to apply electrical stimuli to the piezoelectric membrane. When the frequencies of the electric stimuli are the same as those of the sound stimuli, it is found that the amplification/damping of the local membrane vibration is possible by choosing the appropriate phase difference between the electric stimuli and the sound stimuli. This vibration control technique can be applied to the development of the artificial cochlear epithelium with nonlinear response, which is necessary to mimic the wide dynamic range of human cochlea.