"An ultrasound-powered, 3D visual display that can also produce audible sound and holograms that you can touch been unveiled by researchers at the University of Sussex. The team used the display to produce 3D images such as a torus knot, a globe, a smiley face and letters, as well as a dynamic countdown of levitating numbers.
The display is a type of sonic tractor beam, which uses ultrasound transducers to create acoustic holograms that can trap and manipulate objects in mid-air. The Sussex device uses two arrays of 256 speakers to levitate a single polystyrene bead, which traces out 3D images in mid-air while illuminated by coloured LEDs. The bead can move at speeds of almost 9 m/s (in the vertical direction), which is so fast that an image is drawn in less than 0.1 s. This creates the illusion of a single 3D image in much the same way as a cathode-ray tube creates a 2D image in an old television by rapidly scanning an electron beam across a phosphor screen.
“Our new technology takes inspiration from old TVs,” explains Ryuji Hirayama of the University of Sussex. “Our prototype does the same using a coloured particle that can move so quickly anywhere in 3D space that the naked eye sees a volumetric image in mid-air.”"
https://physicsworld.com/a/ultrasound-device-creates-an-audio-visual-and-tactile-3d-display/
The display is a type of sonic tractor beam, which uses ultrasound transducers to create acoustic holograms that can trap and manipulate objects in mid-air. The Sussex device uses two arrays of 256 speakers to levitate a single polystyrene bead, which traces out 3D images in mid-air while illuminated by coloured LEDs. The bead can move at speeds of almost 9 m/s (in the vertical direction), which is so fast that an image is drawn in less than 0.1 s. This creates the illusion of a single 3D image in much the same way as a cathode-ray tube creates a 2D image in an old television by rapidly scanning an electron beam across a phosphor screen.
“Our new technology takes inspiration from old TVs,” explains Ryuji Hirayama of the University of Sussex. “Our prototype does the same using a coloured particle that can move so quickly anywhere in 3D space that the naked eye sees a volumetric image in mid-air.”"
https://physicsworld.com/a/ultrasound-device-creates-an-audio-visual-and-tactile-3d-display/