“Its a touch screen which provide Programmable friction” which 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.
The touch screen uses high frequency vibrations to create a thin layer of air betweenthe glass and the user’s finger. The finger glides easily over the air layer, but catchesslightly on the glass when the vibrations are switched off. Vary the vibrations thatmove the user’s finger can cause different parts of the screen to feel smooth or sticky
“It adds a sense of realism, “says Vincent Levesque, a computer scientist at theUniversity of British Columbia in Vancouver. “It’s more physical. It feels like there areactual buttons that actually exist. “Levesque and his colleagues have 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, the use of vibration to generate a click or other signal touch. But the new device, called a touch screen model (T-PAD),aims to do more than just buzz or click, says Ed Colgate, a mechanical engineer at Northwestern University, whose team developed the touchscreen.
“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 example, when a finger across a button, the vibrations slow down or stop, giving the impression that this part of the screen is sticky. If you drag a file into a folder, youwill feel the screen becomes sticky as your finger hits the target. Turn a wheel or ascroll bar on the screen, you’ll feel your finger to touch move “graduations.” Regardingthe vibration on and off very quickly-for example, whenever a finger moves amillimeter on-screen may be part of the screen rough feel as if she was covered with a grid.
In a paper presented at the ACM, Levesque and colleagues showed that tactile feedback has allowed people to perform tasks a bit faster. Users also generally likedthe touch screen, although some complained that their fingers got tired after using itfor a while.
“Actually it’s pretty magical when touched. It’s really good,”says Vincent Hayward, a mechanical engineer at the University Pierre and Marie Curie in Paris, who is familiarwith the device. However, it warns that the approach has problems, the prototype is bulky and consumes power. It also provides information that every finger is moving.Tapping the screen does not feel special. He said he expected that tactile displays tofinally make their way into consumer electronics. “A lot of engineering to do, ” admitsColgate. “But it is not theoretically impossible.”