The 3D Display may soon enable Touch in the Digital World

The 3D Display may soon enable Touch in the Digital World

Haptic feedback is a type of technology that gives consumers a sense of touch or tactile feedback when engaging with virtual or digital content. This technology attempts to improve user experiences by mimicking the sensation of touching tangible objects in a digital world. Engineers have created a new shape-shifting display that can fit on a card table and allows users to draw 3D creations and more.

Imagine an iPad that can morph and distort, allowing you to draw 3D artwork, make haiku that pop out of the screen, and even touch your partner’s hand from across the ocean.

That is the goal of an engineering team from the University of Colorado Boulder. They’ve constructed a one-of-a-kind shape-shifting display that fits on a card table in a new study. The device is composed of a 10-by-10 grid of soft robotic “muscles” that can detect outside pressure and pop up to form patterns. It’s accurate enough to generate scrolling text and fast enough to shake a fluid-filled science beaker. It may also provide something even more unusual: a sense of touch in the digital era.

“As technology advanced, we began by sending text over long distances, then audio, and now video,” said Brian Johnson, one of the new study’s two primary authors who will receive his doctorate in mechanical engineering from CU Boulder in 2022. “But we’re still missing touch.”

Johnson and his colleagues described their shape display in the journal Nature Communications.

As technology advanced, we began by sending text over long distances, then audio, and now video. But we’re still missing touch.

Brian Johnson

The group’s idea draws on the work of a team led by Christoph Keplinger, a former assistant professor of mechanical engineering at CU Boulder. Hydraulically Amplified Self-Healing ELectrostatic (HASEL) actuators are what they’re named. The prototype display is not yet market-ready. However, the researchers believe that comparable technology will one day lead to sensory gloves for virtual gaming or a smart conveyer belt that can undulate to separate apples from bananas.

“You could imagine arranging these sensing and actuating cells into any number of different shapes and combinations,” said Mantas Naris, a PhD student in the Paul M. Rady Department of Mechanical Engineering and co-lead author of the work. “There is no limit to what these technologies could eventually lead to.”

3D display could soon bring touch to the digital world

Playing the accordion

The initiative arose from the search for a new type of technology: synthetic organs. Researchers led by Mark Rentschler, professor of mechanical engineering and biomedical engineering, received National Science Foundation funding in 2017 to develop what they call sTISSUE — squishy organs that behave and feel like real human body parts but are made entirely of silicone-like materials. Keplinger, who is now a director at the Max Planck Institute for Intelligent Systems in Germany, is a co-investigator on the program, as are Nikolaus Correll, an associate professor in the Department of Computer Science at CU Boulder, and Sean Humbert, a professor of mechanical engineering.

“You could use these artificial organs to help develop medical devices or surgical robotic tools for much less cost than using real animal tissue,” said Rentschler, one of the study’s co-authors. However, while developing that technology, the team came up with the notion of a tabletop display. The study is a component of the Materials Science and Engineering Program.

The design of the group is around the size of a Scrabble game board and, like one of those boards, is made up of little squares arranged in a grid. In this scenario, each of the 100 squares represents a separate HASEL actuator. The actuators are comprised of tiny accordions-shaped plastic pouches. If you pass an electric current through them, fluid shifts around inside the pouches, causing the accordion to expand and jump up.

The actuators also include soft, magnetic sensors that can detect when you poke them. That allows for some fun activities, said Johnson, now a postdoctoral researcher at the Max Planck Institute for Intelligent Systems.

“Because the sensors are magnet-based, we can use a magnetic wand to draw on the surface of the display,” he said.

Hear that?

Similar smart tablets have been built by other research teams, but the CU Boulder display is softer, takes up less space, and is significantly faster. Its robotic muscles can activate up to 50 times each second.

The researchers are currently concentrating on decreasing the actuators in order to boost the resolution of the display, similar to adding more pixels to a computer screen. “Imagine if you could load an article onto your phone, and it renders as Braille on your screen,” Naris added.

The group is also working to flip the display inside out. That way, engineers could design a glove that pokes your fingertips, allowing you to “feel” objects in virtual reality. And, Rentschler said, the display can bring something else: a little peace and quiet.

“Our system is, essentially, silent. The actuators make almost no noise.”