With a single bead of plastic, scientists tease interactive 3D

British scientists have developed moving three-dimensional images with sound and touch sensations based on a tiny plastic bead moved at high speeds.
Image: Scientists have developed a moving 3D display that can recreate sounds and a feeling of touch.
Scientists have developed a moving 3D display that can be safely touched and interacted with.Eimontas Jankauskis

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By Tom Metcalfe

British scientists have developed a three-dimensional display that moves and can recreate the sounds and even a sense of touch of the objects it shows.

While still in its infancy, the emerging technology has been able to produce small recreations of objects that people can interact with, and it is expected to have applications in architecture, design, biomedical imaging and medicine.

The idea is based on one tiny bead of plastic that is suspended and moved at high speeds by high-frequency sound waves created by an array of miniature speakers.

The bead is then illuminated by computer-controlled lights to create a colored, moving, 3D image that can be viewed from almost any angle.

“We get audio, visual and tactile feedback on the same operating principle,” said Sriram Subramanian, the head of the Interact Lab at the University of Sussex in Brighton, England, and a co-author of new research describing the display.

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Some 3D displays require a projection screen or special viewing equipment, he said, but the new display – dubbed MATD, for Multimodal Acoustic Trap Display – doesn’t need a screen or other aids, and the 3D image can be safely touched.

The MATD system is based on “acoustic tweezer” technology that can suspend particles in space and move them with ultrasonic waves.

The ultrasonic waves are too high-frequency to be heard and aren’t harmful, but they can move the bead rapidly around an empty space about 4 inches across.

The high speed of the bead – up to 28 feet a second – makes it look like a much larger image. Some of the demonstration images show a 3D butterfly flapping its wings, a colored knot and a globe of the world.

The same ultrasonic waves that move the bead and create the feeling of touch can also create sounds that seem to come from the object itself, without affecting the image quality, he said.

“It’s a bit like if you take a straw and blow onto your hand,” he told NBC News. “It’s distinct enough to feel it, but it’s not enough to stop you from doing anything.”

It’s possible on the prototype to interrupt the image by stopping the bead with your hand — causing no harm — but the bead could be easily tracked and the image quickly restored in future systems, he said.

Subramanian said that some of the demonstration videos were made with slow shutter speeds to simulate what the display could do at higher resolutions.

Scientists have developed a moving 3D display that can recreate sounds and a feeling of touch.Eimontas Jankauskis

The display could use more beads and faster speeds for applications like recreating the Princess Leia hologram from “Star Wars” — but that will have to wait for refinements of the prototype, he said

Acoustic tweezers could also be used to deliver drugs within the body, or levitate and move individual living cells – an application being developed in the United States.

“Acoustic tweezers have many inherent advantages, such as high versatility, high precision, high biocompatibility and low cost,” said Tony Jun Huang, a professor of mechanical engineering at Duke University who was not involved in the new research.

“This work on acoustic 3D display is a smart way of utilizing acoustic tweezers and could have significant impact,” he said in an email.