Ultrasonic micromanipulator using visual feedback

We have proposed ultrasonic micromanipulation (UMM) techniques for micron-sized particles in liquid based on the radiation forces of very-high-frequency (VHF) ultrasound. In this paper, we report new UMM techniques using visual feedback techniques. To generate VHF ultrasound, a beam-width-compression leaky wave transducer with a frequency of 50 MHz is used. The 50-mu m-diameter SiO2 glass sphere and the polystyrene sphere are used as test particles. As an example of two-dimensional manipulation, the transportation of particles along circle and character patterns are demonstrated. The selective trapping of a glass sphere is also shown.