Design Of A Lens-focused Transducer Using1-3Piezoelectric Composites

After a decades of vigorous development of diagnostic ultrasound,withthe advancement of science and technology,an unprecedented period ofdevelopment is coming for therapeutic ultrasound as well.Generallyspeaking,the focused ultrasound is the typical representative of therapeuticultrasound.Focused transducer is the core of the focused ultrasound therapyequipment and for focused transducer,the transducer material is the mostcritical.For some reasons,the focused transducer used for clinical is usuallymade up of piezoelectric ceramic,and there are some problems need to besolved.1-3composites,which is an important class of functionalmaterials,has been widely used in the field of underwater ultrasound anddetection ultrasound already.Compared with the piezoelectric ceramic,thereare some superiorities of1-3composites,which can provide reference valuefor the introduction of new transducer material into therapeutic ultrasoundfield.To solve the problems of lens-focused transducer and suppress themult-mode coupling effect and improve the electro-acoustic conversion efficiency of a single lens-focused transducer made of the piezoelectricceramic material, a single lens-focused transducer using1-3piezoelectriccomposites is designed. First, the thickness resonant frequency ftandthickness electro-mechanical coupling coefficient ktof the1-3piezoelectriccomposites were calculated and simulated, the difference between thetheoretical value and the simulation value for ftand ktare2.52%and0.32%respectively. Next, the vibration condition of the transducer was analyzed.At the resonant frequency f of the transducer, the displacement amplitude atradial direction of the acoustic lens center is only7.9%of the thicknessdirection, which shows that the radial vibration is suppressed effectively,and thus the electro-acoustic conversion efficiency of transducer isimproved.This study could be used as reference in the development workon focused transducers.