Robots with a sensitive touch

Organic transistors with pressure sensors prepare the way for artificial skin.

For those of us who struggle to set the video, a life where robots do our chores is certainly not the stuff of dreams and in any case seems a million miles away. However, Japanese researchers are hard at work developing such robots and one team now claims to have developed an artificial ’electronic skin’, which could give home robots a sensitive touch.

Although robots can already do a frightening number of everyday tasks, none of them has a sensitive artificial electronic skin, primarily because silicon-based electronics are no good for the flexible switching matrix required. Takao Someya, from the Quantum-Phase Electronics Center at the University of Tokyo in Japan, believes that the future lies in organic circuits. These are both flexible and cheap and Someya suggests that combining organic transistors with rubber pressure sensors paves the way to a ’practical artificial skin’.

Someya and his research team have developed a large-area pressure sensing device. This comprises a poly(ethylene napthalate) base film which is coated with various polymer and metal layers and a pentacene layer to act as a series of transistors. A pressure-sensitive rubber sheet is laminated to the bottom of the base film. In tests, the device could take ’pressure images’ even when the sheet was bent, although the gold transistors limited the amount that it could be deformed by. For a bit of fun, the team tested the device using a rubber stamp in the shape of human lips. ’Even though the resolution of the present device is too low for the sensor to identify whose lips it is touching, the experience is conclusive enough to fuel one’s imagination’, they joked.

The researchers think that they could make the device more like human skin by increasing the density of the sensor cells and incorporating artificial sensors for temperature and humidity. Someya considers that the stability of the organic transistors still needs to be improved but his team is currently working on this. He is optimistic that the artificial skin could be used in real products in five years time. Someya told Chemistry World that his research group has received ’lots of feedback’ from various industries.

Someya is certainly not short of ideas. One involves using the new technology to develop carpets for the elderly which would contain sensors to detect whether a person has collapsed and then to monitor heart rates and breathing.

Emma Davies