Noncontact Transportation Using Ultrasound

Abstract

Acoustic radiation force is a static force generated by a difference in the acoustic energy densities of two media. Small objects can be levitated and transported by acoustic radiation force in an acoustic standing wave. The present paper introduced noncontact ultrasonic transportation of small objects: linear transportation over a long distance, transportation in a circular trajectory, and two-dimensional transportation. In these techniques, the ultrasound vibration of a plate and the sound pressure distribution can be controlled by the electric input to piezoelectric ultrasound transducers, enabling the control of positions where the objects were trapped. The configuration of the systems can be determined by finite element analysis, and the acoustic field and the transportation trajectory of the manipulated objects can be predicted by the theoretical equation of the acoustic radiation force. These techniques are expected to be applied to not only product lines for precise electronic components and tablets but also a manipulation of powder, liquid, and cells in the field of biotechnology.

Graphical Abstract