Electronic stethoscope is an instrument used for auxiliary determination of patients＇ physical condition by collecting and processing heart sounds and lung sounds.Since traditional electronic stethoscopes have low sensitivity and poor low-frequency response,a novel electronic stethoscope is provided in this paper using curved PVDF clamping structure with non-uniform curvature based on the structure of PVDF and silicone rubber substrate.Theoretical analysis and comparison by means of the corresponding inhomogeneous string vibration model show that sensitivity significantly increases for non-uniform curvature than the uniform one.Furthermore,a new electronic stethoscope pickup is developed based on the optimal parameters at the point of maximum sensitivity of non-uniform curvature.Experiment results show that the sensitivity of the pickup can reach1.7mV/Pa,which increases by 13.3%compared to the one with the structure of uniform curvature PVDF and silicone rubber substrate that has been studied in recent years.Moreover,flat frequency response characteristics can be retained within the frequency band range of 2-2kHz,which covers the frequency response range of cardiopulmonary sound collection,thus provides a strong guarantee for complete acquisition of heart and lung sound signals.
