Japanese scientists create touchable holographic 3D displays using ultrasound tactile display

A team of scientists form the University of Tokyo have made a new touchable 3D holographic display. They are using their airborne ultrasound tactile display to create a sensation on the user's hand without any direct contact, and without interfering with the holographic display.

The touchable hologram's visual component is generated by projecting an image from an LCD projector onto a concave mirror. The ultrasound 'display' radiates airborne ultrasound, and produces high-fidelity pressure fields onto the user's hands, without the use of gloves or mechanical attachments. This is based on a nonlinear phenomenon of ultrasound: acoustic radiation pressure (when an object interrupts the propagation of ultrasound, a pressure field is exerted on the surface of the object). With an ultrasound transducer array, various patterns of pressure field are produced in 3D free space.

"The Airborne Ultrasound Tactile Display is guided by a "vision-based hand tracking system," the team explains, adding that "the tactile display exerts the radiation pressure on the user's hands when they 'touch' 3D virtual objects." 

Via ITVT