Straight to the point

The ability to control electronic devices by simply pointing a finger is being made a reality by a €2.2m (£2m) pan-European project led by the Fraunhofer Institute.

The 3Plast project (printable pyroelectrical and piezoelectrical large-area sensor technology), aims to combine polymer sensors with organic electronics to develop substrates that can react to changes in heat and movement.

Principle investigator Dr Gerhard Domann said that this will soon remove the need for people to directly touch human-computer interfaces and could open up a range of applications in sectors including robotics, automotive and construction.

The project focuses on piezoelectric polymers, which expand and contract under the influence of an electric field, and pyroelectric polymers that are electrically polarised due to temperature changes. These materials will be used to fabricate thin-film capacitors that are integrated along with organic transistors.

’Pyroelectrical and piezoelectrical polymers are now being processed in high volumes using roll-to-roll screen-printing techniques,’ explained Domann. ’If we combine this with organic transistors, we can increase the signal-processing function and give it the two most important characteristics of human skin sensitivity to pressure and temperature.’

One key area that the project hopes to address is integrating the transistor within the system by printing it directly onto the material. This will allow rapid changes in temperature and pressure, and removes the need to join the components using a separate method.

A further challenge, said Domann, is reducing the thickness of the insulation materials in order to allow high-speed processing techniques and make the material sufficiently flexible. So far, the researchers have been able to produce a sensor that is 100nm thick and are now working on printing smoother substrates for more reliable sensor performance.

’At the moment, it’s difficult for the industry to imagine the tremendous number of possibilities existing for these kinds of sensors,’ said Domann. ’In the end, a completely different application could emerge that we haven’t yet thought about.’

Applications currently being investigated by UK researchers in this area include intelligent wallpaper, wearable smart cards and sensors, flexible radio-frequency identification (RFID) and interactive advertising displays.

The project is due to end in January 2011, by which time the team hopes to have addressed the issues preventing widespread commercialisation of the technology.