Hologram-like device animates objects using ultrasound waves
A demonstration of the display showed a butterfly flapping its wings, a countdown spelled out by numbers hanging in the air, and a rotating, multicoloured planet Earth. Beyond interactive digital signs and animations, scientists want to use it to visualise and even feel data.
While the images are similar, the device is not the sort of holographic projector that allowed a shimmering Princess Leia to enlist Obi-Wan Kenobi’s help in Star Wars. Instead, it uses a 3D field of ultrasound waves to levitate a polystyrene bead and whip it around at high speed to trace shapes in the air.
The 2mm-wide bead moves so fast, at speeds approaching 20mph, that it traces out the shape of an object in less than one-tenth of a second. At such a speed, the brain doesn’t see the moving bead, only the completed shape it creates. The colours are added by LEDs built into the display that shine light on the bead as it zips around.