Quantum Tunnelling Touchscreens Touted For Tablets

Yorkshire-based Peratech can now make tablet-sized touchscreens like a quantum jam sandwich

British firm Peratech today unveiled a new transparent version of its quantum tunnelling composite (QTC) material, which the company claims could replace current touchscreen technology used in smartphones and tablets.

The technology – proposed last year for smartphones and switches – has now grown up to create tablet-sized touchscreens. These will use less power than alternatives, and will allow better interaction, since they can respond to how hard a user presses, as well as to where their finger is.

Quantum tunnelling with spiky particles

QTC technology works by quantum tunnelling between conductive nano-particles, embedded in an insulating elastomeric binder. When pressure is put on the material, the nano-particles – which are spikey like medieval maces – get closer together, allowing electrons to ‘tunnel’ between them. This turns the pressure into an electrical signal.

The technology can be used to create force-sensitive touchscreens that conduct better when they are pressed harder. For example, a user could increase the speed of scrolling through a list of contacts by exerting more pressure on the screen. Peratech claims that QTC could completely replace current resistive touchscreen technologies, and also enhance capacitive ones.

“Both resistive and capacitive touchscreen technologies have their drawbacks,” explained Philip Taysom, Peratech’s joint CEO. “Resistive is not very accurate and can’t do multi-touch so it is becoming less popular than capacitive, but the latter uses a lot of power, constraining it to smaller screen sizes.

“Our new, QTC Clear touchscreen design offers the best of both technologies without their drawbacks. It can be made in any size and provides multi-touch, high sensitivity with great accuracy, ultra low power consumption and additional intuitive features with the third dimension of pressure to more easily manipulate and control information on the screen.”

A quantum jam sandwich

When built into touchscreens, QTC acts like the jam in a jam sandwich – where the butter is a thin layer of Indium Tin Oxide (ITO) and the bread is the glass. The QTC Clear layer is only 6-8 microns thick.

David Lussey, Peratech's CTO, with QTC Clear

Peratech has been building its QTC into touchscreen devices for over a year, but the new QTC Clear technology will help to improve accuracy, because the ‘jam’ covers the whole screen rather than just the edges (or the ‘crusts’) of the device. This not only makes the device more sensitive to touch commands – because it is able to sense exactly where the pressure is being exerted rather than approximating – but also enables multi-touch.

Unlike capacitive touchscreens, which use a lot of energy because they have a current running through them constantly, QTC draws virtually no current unless a force is applied. This means it is suitable for much larger screens.

The company claims that capacitive touchscreen manufacturers that build QTC Clear into their devices will be able to provide additional features from the force sensitivity, such as 3D menus, variable line widths, and more intuitive gaming interaction.

They can also reduce the power use of the screens, by using the QTC Clear screen to selectively activate parts of the capacitive matrix, eliminating the need for a constant current.

“This is a very interesting new technology that could revolutionise the whole touchscreen industry from automotive to computers,” said Paul O’Donovan, principal analyst at Gartner’s semiconductor division.

Growth of touchscreen technology

The news follows a report last month that a Cambridge University-backed company has developed an acoustic processing technology, in the form of a software-only upgrade, that could one day offer another alternative to the touchscreens currently used in smartphones and other devices.

The technology, called TouchDevice relies on the acoustic signal produced by the user swiping or tapping on the display to effectively simulate a touchscreen. The technology isn’t limited to the display screen, as users can tap or swipe on the entirety of the handset case, the company said.

Touchscreens have increased dramatically in popularity over the last year, thanks largely to the success of Apple’s iPhone and iPad, which use capacitive touchscreen displays. There are just over 20 million tablets in use today, with a market potential of over 180 million sales by 2014, according to RBC.

“People are so much more comfortable now,”  said Mike Stinson, Motion’s vice president of marketing, speaking to eWEEK Europe in January. “Touching the display has become acceptable.”