Peratech (Richmond, UK) has developed a see through version of its Quantum Tunnelling Composite (QTC) force sensing material. QTC Clear which can be used touch screens that can completely replace current resistive touch screen technologies or enhance capacitive ones to create superior solutions with more features such as 3D input.
The QTC Clear layer is 6-8 microns thick, about half that of the existing QTC-based materials, with a transparency that is very similar to the existing touch screen technologies. This is sandwiched between two layers of Indium Tin Oxide, which is in turn sandwiched between two hard sheets, typically glass. The picture shows David Lussey, Peratech's CTO, with a sheet of QTC Clear.
It can detect deflections of only a few microns so that the top surface can be rigid and robust such as glass, unlike current resistive designs that have to be soft enough to deform making them susceptible to damage. With QTC technology virtually no current flows unless a force is applied which overcomes the drawbacks of capacitive designs that constantly draw current and create design challenges to overcome EMI issues.
Philip Taysom, Peratech’s Joint CEO, said that there had been consistent demand from licensees for the company to product a transparent version of its material. QTC Clear is available under license from Peratech and has already been licensed to a leading touch screen manufacturer in the small screen sector up to 5.5 inches. “We are in the third stage of development and the licensee is doing production scale trials having moved from the lab volumes to reasonable quantities. The aim is we will be ready for commercial delivery by the third quarter of this year.”
The technology will enable larger touch screens for both computers and televisions. “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,” said Taysom. “When you are moving beyond 25 inch screens you cannot easily construct resistive touch screens of that size as in order to maintain the stand-off between the layers the top surfaces becomes 'saggy' and you end up with something than has low registration and have huge limitations on how you can detect touch.”
According to Taysom, Peratech licensing model is not typical. “A lot of companies would sell a 'license' to experiment with the material. A license to us is royalty-generating, so when somebody is ready to put a product in to production.” The number of licensees has increased from 1 or 2 to 9 in the last 18 months with two more expected to sign up in the next quarter. At present the company manufactures the material in the UK but is looking to establish a manufacturing plant in the Far East with an announcement about that due later this year.