Basic resistive or capacitive technologies are fine for locating where a screen is being touched but poor at gauging the pressure of the touch. The new technology from a company called Peratech, which is based in Richmond, North Yorkshire, uses a material called Quantum Tunnelling Composite (QTC), the resistance of which is extremely sensitive to pressure.
This means it can make writing on screens more like writing with pencil and paper, when the harder you press the thicker the line you produce. Peratech has just announced a $1.4m deal to licence the technology to Japanese mobile screen manufacturer Nissha.
Peratech says there is a lot of interest in the technology in the Far East for use in handwriting recognition, because Asian scripts use a lot of variation in line thickness. But pressure can also be used to control other parameters, for instance to facilitate navigation of 3D virtual worlds.
Takao Hashimoto, chief technology officer of Nissha, said: "QTC will be a disruptive technology for mobile phones enabling thinner phones to be designed with amazing new input interfaces."
Chris Lussey, joint chief executive of Peratech, said: "QTC changes the game when it comes to human machine interface design with capabilities to build truly 3D user interfaces in small, low power devices. This three dimensionality cannot be matched with existing resistive and capacitive technologies."
Quantum tunnelling is the passage of electrons across an extremely narrow gap containing what would normally be an insulator, when the electron behaves like wave rather than a particle. The QTC material contains of spiky nanometre-scale metal particles covered with a silicone insulator. The spikes concentrate charge at their tips, decreasing the energy required for electrons to tunnel.
The QTC layer has two other advantages. It is very thin, around 75 micrometres; and unlike rival technology it does not incorporate an air gap, making it both more sensitive and easier to manufacture.
Screens with a standard 2D touch matrix can get the extra measure of control using a narrow strip of QTC down the side. This responds to deformation caused by pressure anywhere on the screen; software can then estimate the pressure at the point of touch.
A fuller explanation of the technology can be found here.