On the Technology of Acoustic Utility. Acoustic Information and Energy. Two-Dimensional Micromanipulation Using an Ultrasonic Standing Wave Field Generated by Crossing Sound Beams.

Abstract

As a non-contact maicromanipulation technique, it is possible to trap particles in water at nodes of an ultrasonic standing wave field generated between a transducer and a reflector and to transport them using a frequency-shifting operation. Since there are several problems coming from resonance of the sound field with this scheme, the authors proposed a novel manipulation technique for particles using a standing wave field generated by two transducers whose sound beam axes were crossing to each other and accomplished one-dimensional manipulation of a polystyrene particle. The present paper describes an extension of this method adding one more transducer, which realizes two-dimensional manipulation suppressing unstable motion observed in the one-dimensional operation. Experiments in water using polystyrene particles confirmed the principle of the two-dimensional manipulation and agreed well with a numerical analysis of the sound field.