基于 PVDF 非均匀曲率半径结构的高灵敏度电子听诊器

电子听诊器是利用电子技术收集处理心肺音,并依此辅助判断病人身体状况的一种仪器。针对传统电子听诊器灵敏度低、低频响应差等缺点,基于 PVDF 非均匀曲率半径的弯曲夹紧结构,提出了一种高灵敏度的电子听诊器设计方案。通过建立相应的非齐次弦振动模型,理论分析比较证明了非均匀曲率相比均匀曲率的灵敏度有显著提高,并优选非均匀曲率半径结构灵敏度最大的参数研制出一款新型电子听诊器拾音器。实验测试结果表明,该拾音器的灵敏度达到1.7 mV/Pa,相较近年来研究的均匀曲率半径 PVDF 与硅胶衬底组合结构的拾音器灵敏度提高了13.3%。该拾音器能在2-2 kHz 频带范围中保持平坦的频响特性,涵盖心肺音采集的频响范围,为较完整地获取心肺音信号提供有力保障。

Highly sensitive electronic stethoscope based on non-uniform PVDF curvature structure

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-fre-quency response,a novel electronic stethoscope is provided in this paper using curved PVDF clamping structure with non-uni-form 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 reach 1.7 mV/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 fre-quency band range of 2-2 kHz ,which covers the frequency response range of cardiopulmonary sound collection,thus provides a strong guarantee for complete acquisition of heart and lung sound signals.