Aerial display of vibrotactile sensation with high spatial-temporal resolution using large-aperture airborne ultrasound phased array

We fabricated a tactile display which can generate vibrotactile sensation on human skin on which no equipment is mounted. It utilizes focused airborne ultrasound radiation pressure for stimulation. The workspace of our new tactile display is widened to a cube of 1 m × 1 m × 1 m, which allows users free motions in it. In order to widen the workspace, our new prototype integrates multiple ultrasound transducer units and achieves a large aperture airborne ultrasound phased array. As the workspace is widened, it has become possible to stimulate arbitrary regions all over a human body. The amplitude of imposed radiation pressure can be time-variant. The profiles of generated vibrotactile stimuli can be designed with a temporal resolution of 0.5 ms and 320-level quantization of radiation pressure amplitude. It is easy to choose a recorded waveform and reproduce it as vibrotactile stimuli at an arbitrary spatial point. This paper introduces how our new tactile display works and reports its performance evaluation.