New meaning of “touch screen”

Interesting research from Nokia:

Nokia has developed a prototype of its N900 smartphone that lets you feel the texture of icons on the screen — a technology that would add a whole new dimension to touchscreen apps.

This week, Nokia researcher Piers Andrew showed how the technology could give each icon its own feel or add surface texture to photographs. The idea is to have everything on a touchscreen give tactile feedback, Andrew says.

The technology is based on an effect called electrovibration, in which touch receptors in the skin can be fooled into perceiving texture when you swipe a fingertip across an insulating layer above a metal surface carrying an alternating voltage. The higher the frequency of that alternating voltage, the smoother the texture feels.

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The effect is thought to be due to the varying electrostatic attraction between the metal and the deeper, liquid-rich conducting layers of the skin — an effect which changes the perceived friction level.

To mimic this is in a touchscreen phone, Nokia placed two thin layers above the LCD display: the first a transparent conductor, indium tin oxide, and the second a transparent insulator, hafnium oxide. When the user cradles the phone in one hand and touches the screen with the fingers of their other hand, they effectively create a closed circuit. If the indium tin oxide is excited at frequencies between 50 and 200 hertz, the finger above the touchscreen is attracted towards the screen with varying strength, generating the textured effect.

They acknowledge that it’s not ready for production yet, and This is not necessarily the most attractive sensation for some people.

Still, it sounds very interesting.