Pressure pulse source for lithotripsy - has pulsed diaphragm in acoustic medium with layer of lower acoustic impedance

摘要

The pressure pulse source employs a pulsed diaphragm (11) in an acoustic medium (21) and a layer (20) between the diaphragm and medium whose (20) acoustic impedance is lower than that of the medium and which borders directly on the diaphragm. The thickness (d) of this layer (20) or the distance between the layer-adjoining boundary surface between two layers of differing impedance and the diaphragm is one quarter wavelength of the fundamental wavelength of the pulse produced in this same layer (20). One of the layers adjacent to layer is in foam form, with low impedance medium held in the foam pores. USE/ADVANTAGE - Non-invasive surgery, lithotripsy, materials testing etc. Low impedance layer(s) between diaphragm and medium maximises pulse energy content and pressure effect.