Patent ID: 7264597

Claim:
A device for producing high pressure ultrasound pulses in a coupling medium, the device comprising: an ultrasound source comprising a piezoelectric type transducer provided with electrodes and presenting polarization in a given direction (f 1 ); and means for applying an electrical voltage to the electrodes of the piezoelectric type transducer, serving, in order to emit an ultrasound wave: to apply a progressive electric field in the direction (f 2 ) opposite to the polarization direction (f 1 ) in order to compress the piezoelectric type transducer; and then to apply a transient electric field having a rise time (t 3m ) in the same direction (f 3 ) as the polarization direction (f 1 ), so as to cause a compression ultrasound wave to be emitted in the coupling medium; wherein the progressive electrical voltage has a rise time (t 2m ) for creating an electric field of direction (f 2 ) which has a duration (T) that is shorter than the duration necessary to depolarize the piezoelectric type transducer, the rise time (t 2m ) being at least ten times greater than the rise time (t 3m ) of the transient electric field.