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 vibrati…
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 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. 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. 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.