Peratech have developed a transparent version of their award winning Quantum Tunnelling Composite (QTC™) material, called QTC Clear™. This force sensing material can be used to create a whole new class of force sensitive touch screens that can completely replace current resistive touch screen technologies or enhance capacitive technologies to create superior solutions with more features, such as 3D input.
According to Philip Taysom, Peratech’s Joint CEO, resistive and capacitive technologies both have drawbacks. Resistive is not very accurate and doesn’t allow multi-touch, so it is less popular than capacitive, while capacitive uses a lot of power, limiting it to smaller screen sizes. Peratech’s new QTC Clear touch screen material offers the best of both technologies without their drawbacks. It can be fabricated in any size and provides multi-touch capability and 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.
The QTC Clear layer is only 6 to 8 microns thick, with transparency very similar to existing touch screen technologies. It is coated on both sides with indium tin oxide and sandwiched between two hard sheets, typically glass. The material is so sensitive that it can detect deflections of only a few microns, allowing the top surface to be rigid and robust, unlike current resistive designs that must be soft enough to deform easily and are susceptible to damage.
QTC is a low power technology, and interfaces can be designed so that the sensing element draws no power and passes no current unless it is touched. When pressure is applied, the resistance drops in proportion to the amount of pressure, which allows sophisticated human machine interface designs that respond to differences in pressure. QTC technology has no moving parts and requires no air gap between contacts. This makes it extremely reliable and suitable for integration into ultra-thin designs.