Synthesized-sound manipulation of micro-particles: Principle and experiments

In this paper, we present a sound field synthesis technique based on the mode-matching and inverse-filtering to manipulate micro-particles within a given region. The technique employs a set of PZT transducers evenly placed on the perimeter of a 50 mm-radius circle to generate and manipulate the desired local ultrasonic filed. Adjusting the parameters of driven signals applied to the transducer array results in the movement of the synthesized pressure field and hence the micro-particles. We have theoretically derived the method to calculate the ultrasound transducer operating parameters that are required to synthesize the desired local ultrasonic filed in a chamber filled with deionized water. Micro-particles with 10 μm-diameter are adopted as the manipulating targets and several experiments have been developed to validate the synthesizing method. The method introduced here may become a promising tool for various applications in the field of biological, material, and microelectronics.