Three-Dimensional Mid-Air Acoustic Manipulation ( Acoustic Levitation )   Yoichi Ochiai / 落合陽一(The University of Tokyo / 東京大学) Takayuki Hoshi / 星貴之(Nagoya Institute of Technology / 名古屋工業大学) Jun Rekimoto / 暦本純一 (The University of Tokyo / Sony CSL) The essence of levitation technology is the countervailing of gravity. It is known that an ultrasound standing wave is capable of suspending small particles at its sound pressure nodes and, so far, this method has been used to levitate lightweight particles, small creatures, and water droplets. The acoustic axis of the ultrasound beam in these previous studies was parallel to the gravitational [More]