Quantum Material ‘Could Replace All Switches’

“The capacitive touchscreen detects your finger’s position, the press on the glass causes our QTC material to give a resistance change,” he said. This combination can produce the equivalent of a hover or a left or right click on a touchscreen, or could be built into applications in a context-sensitive way. For instance, Google Maps could use it to zoom in on where the user is pressing.

The pressure applied is effectively a third dimension – a ‘z’ co-ordinate alongside the x and y provided by the touch-screen – but that dimension can be used for anything the software designer wants.

The combination with normal touchscreens works well, he said, and enhances the capacitive screen in more ways: “Capacitive touch is a really good system and there is no need to replace it. But capacitive matrices draw a current when they are one, while our technology only actuates when a gentle force is applied.”

Touchscreens currently drain power gently all the time, but a QTC border could be used as an on-off switch for them, saving power and extending battery life.

Outside phones

Beyond phones, there are other things it could be used for. In robotocs, a hand with sixteen of these sensors has been built, and Taysom believes it will pass the “polystyrene cup test” – in other words, it will be able to pick up a fragile object by applying just enough pressure without crushing it.

Similar sensors on robotic or prosthetic feet could help a robot or an amputee balance, by feeding back how much pressure is being exerted at each side of the foot.

The material is in fact already shipping in wearable textiles that include a switch for controlling an iPod, for instance from Eleksen. “They can be washed up to fifty times, and operate when wet,” said Taysom.

The origin of QTC

QTC got its start when CTO David Lussey was looking for a conductive adhesive, said Taysom. Lussey mixed a conductive nanoparticle with a polymer and mixed it “in a way which was obvious to him but wouldn’t have been obvious to a polymer chemist,” and produced something that wasn’t conductive.

Lussey went to tear the material apart, and his Ohmeter suddenly showed conduction. “This intrigued the genius in David,” said Taysom.

Scientific advisor Professor Daivd Bloor, of Durham Unversity helped Lussey determine that the effect was quantum tunnelling, not a percolation of electrons through the polymer – an important distinction.

“Percolation would make permanent electrical pathways and produce erratic behaviour,” said Taysom. “It would not be repeatable.”

The company also had help from Professor Cyril Hilsum director of technology at GEC for more than twenty years, and credited with the invention of the liquid crystal display (LCD).

And this emphasis on the underlying science goes on – the group hopes to extend it to handle larger voltages than those present in portable devices: “One area of research is controlling mains voltage,” said Taysom. “It can carry much higher currents. You will see a lot of change on that in the next few years, maybe extending to white goods.”

Although it currently works with the capacitive screen it might eventually replace it, even though it can never be transparent. Future LED developments will produce screens so thin, they can transmit pressure through to a QTC layer behind them, suggests Taysom. “When screens get thin enough, we won’t need capacitive touch at all – and that could happen in no more than three years.”

All in all, the technology keeps turning up new opportunities: “It’s an amazing tech, and we keep on doing new things with it – it’s fantastic position to be in,” said Taysom.