【摘要】 分析了高频超声波垂直透过5层不同厚度介质的传播特性,利用传递矩阵推导出超声波在此多层结构的零界面处反射系数与各层介质厚度关系的解析表达式,用解析解做数值模拟,并用COMSOL有限元仿真验证,得到了超声回波在时域上的声学特征.使用高频超声换能器激发与采集分层介质中的超声宽频信号,得到玻璃层和模拟指纹层间反射回波中带有指纹特征的信息,形成了高精度超声指纹图像.更多还原

【Abstract】 The propagation characteristics of high frequency ultrasonic wave transmitted vertically through five layers of different medium thickness were analyzed,and the analytical expression of the relationship between the reflection coefficient of ultrasonic waves at the zero interface of this multilayer structure and the thickness of each medium layer was derived by using the transfer matrix.The acoustic characteristics of ultrasonic echo in time domain were simulated by numerical simulation with analytical solution and finite element simulation with COMSOL.The acoustic characteristics of ultrasonic echo in time domain were obtained.The wide spectrum ultrasonic reflection signal of fingerprint layer was detected by using high frequency ultrasonic transducer in the multilayer media,and interface echo data of glass interface with fingerprint resin layer were obtained.The information with human body fingerprint feature under high impedance glass layer was extracted,which could produce an ultrasonic fingerprint image with high imaging accuracy.更多还原