Research On Broadband Ultrasound Transducers For Photoacoustic Imaging

Ultrasonic testing(UT)is one of the main methods of non-destructive testing(NDT),because of its strong penetrating power,high sensitivity,safety(mechanical waves),real-time,convenient and easy operation,etc.,it has become a more frequently used industry and medical detection method.The ultrasonic transducer has a key role in ultrasonic detection.It converts alternating electrical signals into acoustic signals within the ultrasonic range or converts acoustic signals in the external sound field into electrical signals,thereby completing the mutual conversion of electrical energy and acoustic energy.This article aims to increase the bandwidth of ultrasonic transducers.The equivalent circuit model,finite element simulation analysis,process manufacturing,and other work of micromechanical ultrasonic transducers(CMUTs)are studied.At the same time,photoacoustic imaging is the basic designed a nanosecond laser driver.The specific research content is as follows.The specific research contents are as follows: work in the field;at the same time,a nanosecond laser driver is designed based on photoacoustic imaging.(1)The spring-mass-damping model is used to analyze the CMUT.An equivalent circuit of electricity,force,and sound is established.The effects of atmospheric pressure,resonance frequency,collapse voltage,and mechanical impedance on the CMUT are analyzed.Which laid the foundation for the establishment of simulation models.(2)COMSOL Multiphysics finite element analysis software was used to establish the CMUT model in two-dimensional axisymmetric and three-dimensional space.The steady state,characteristic frequency,prestressed frequency domain,and small signal analysis were performed under the conditions of electromechanical,pressure-acoustic independence,and coupled physics.Analysis in the frequency domain and other research types,extract relevant parameters and further determine the collapse voltage,vibration frequency,bandwidth and sensitivity of the CMUT.(3)The two main manufacturing processes of CMUT,namely sacrificial release process and wafer bonding process,are studied.The advantages,disadvantages and application of the two processes are further analyzed to provide basis for processing and manufacturing CMUT components.(4)According to the principle of photoacoustic imaging,a low-cost,compact nanosecond laser pulse driver is designed,which improves the imaging speed,reduces the complexity of the laser,the overall structure of the driver is more compact,and the photoacoustic microimaging is greatly reduced cost.