APPARATUS AND METHOD FOR MANIPULATING ENTRAINED PARTICLES

摘要

Apparatus and method for manipulating particles entrained in a fluid. The apparatus comprises a signal generator (4) and an ultrasound transmitter. The signal generator is arranged to generate driving signals. The ultrasound transmitter comprises at least first and second groups of transmitter elements and is arranged to transmit respective first and second ultrasound beams in response to respective first and second driving signals received from the signal generator to form a composite ultrasound beam. The signal generator is arranged to generate first and second driving signals that are out of phase, the first driving signal being arranged such that the first ultrasound beam produces a lower time averaged acoustic radiation force than the second ultrasound beam, and such that at least part of region of the composite ultrasound beam corresponding to the interface between the first and second ultrasound beams exhibits a pressure minimum.