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Finnish startup could have the answer to curved touch sensors

Touch screen technology has so far been reserved for flat surfaces only, primarily smartphones and tablets.

But Finnish startup Canatu aims to change all that, by creating transparent films that can turn any surface, regardless of its shape, into a touch sensor.

The transparent films contain carbon nanobuds - molecular tubes of carbon with ball-like appendages. They have a vast potential, and could be used, for example, to turn a car dashboard and curved consoles into a touch sensor.

The films are also very rugged and can be bent over very thin objects, like cables and cords, potentially placing controls and buttons where they usually couldn't be placed.

Touch screens are made by overlaying a display screen with a transparent sheet of indium tin oxide. But because of the sheet's composition, the surface had to be flat.

Individual carbon nanotubes were seen as a good alternative, but their poor conductivity rendered them bad in touch screen technology.

Carbon nanobuds show more promise, because of their ball-like appendages, which improve the electrical connections.

At this moment, Canatu is working on 40 different prototype projects. It recently bought its first full-scale manufacturing equipment, capable of producing enough film for hundreds of thousands of smartphone touch screens every month.

The nanobud films can stretch over a surface, sometimes by more than 200 per cent without losing performance, says Erkki Soininen, vice president of marketing and sales.

Most other stretchable touch screens stretch by only a few per cent.