Skip to Content

A Touch Screen that Plays Sticky

“Programmable friction” provides a new kind of feedback.

An experimental touch screen that uses variable friction to make different areas feel sticky or rough could point the way to a new paradigm in interfaces.

Rough ride: The T-PaD display generates a tactile sensation as a user operates a virtual scroll bar.

The touch screen uses high-frequency vibrations to create a thin layer of air between the glass and the user’s finger. The finger slips easily over the layer of air but catches slightly on the glass when the vibrations are turned off. Varying the vibrations as the user’s finger moves can cause different parts of the screen to feel slick or sticky.

“It adds a feeling of realism,” says Vincent Lévesque, a computer scientist at the University of British Columbia in Vancouver. “It’s more physical. It feels like there are real buttons that actually exist.” Lévesque and colleagues demonstrated a prototype of the device at the ACM Conference on Human Factors in Computing Systems in Vancouver this week.

The screen is one of a number of new devices that offer complex tactile feedback. Some mobile phones on the market, for example, use vibrations to generate a click or some other tactile signal. But the new device, called a tactile pattern display (T-PaD), is meant to do more than just buzz or click, says Ed Colgate, a mechanical engineer at Northwestern University whose team developed the touch screen.

“We’re not just about giving signals,” he says. “We’re about giving physical sensations like the experience you have when you interact with the real world.”

The T-PaD uses piezoelectric discs positioned against a glass plate. When a current is run through the discs, they vibrate at 26 kilohertz and transmit the vibrations to the glass. Lasers track the motion of a user’s finger and vary the vibrations accordingly.

For instance, when a finger runs across a button, the vibrations will slow or stop, giving the impression that that part of the screen is sticky. If you drag a file into a folder, you’ll feel the screen get sticky as your finger hits the target. Turning a wheel or moving a scroll bar on the screen, you’ll feel your finger move over tactile “tick marks.” Turning the vibrations on and off very quickly—for instance, every time a finger moves a millimeter across the screen—can make part of the screen feel rough, as if it is covered with a grating.

In a paper presented at the ACM conference, Lévesque and colleagues showed that the tactile feedback allowed people to complete tasks slightly more quickly. The users also generally liked the touch screen, although some complained that their fingers became tired after using it for a while.

“It’s actually quite magic when you touch it. It’s really neat,” says Vincent Hayward, a mechanical engineer at Université Pierre et Marie Curie in Paris, who is familiar with the device. However, he warns that the approach has problems—the prototype is bulky and uses a lot of power. It also provides feedback only while a finger is moving. Tapping on the screen doesn’t produce any special sensation. He says that he expects the tactile displays to eventually make their way into consumer electronics. “There’s a lot of engineering to be done,” admits Colgate. “But it is by no means theoretically impossible.”

Keep Reading

Most Popular

Image of workers inspecting solar panels at a renewable energy plant
Image of workers inspecting solar panels at a renewable energy plant

Renewables are set to soar

The world will likely witness a wind and solar boom over the next five years, as costs decline and nations raise their climate ambitions.

light and shadow on floor
light and shadow on floor

How Facebook and Google fund global misinformation

The tech giants are paying millions of dollars to the operators of clickbait pages, bankrolling the deterioration of information ecosystems around the world.

wet market selling fish
wet market selling fish

This scientist now believes covid started in Wuhan’s wet market. Here’s why.

How a veteran virologist found fresh evidence to back up the theory that covid jumped from animals to humans in a notorious Chinese market—rather than emerged from a lab leak.

travelers walk through Ronald Reagan Washington National Airport
travelers walk through Ronald Reagan Washington National Airport

We won’t know how bad omicron is for another month

Gene sequencing gave an early alert about the latest covid variant. But we'll only know if omicron is a problem by watching it spread.

Stay connected

Illustration by Rose WongIllustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at with a list of newsletters you’d like to receive.