Prints of light

A technique that allows electronic circuits to be printed on a wide array of surfaces could lead to new products such as transparent solar panels that are thin enough to be used as tint on windows.

The technology from

, a University of Illinois spin-out, uses a rubber stamp-like method to bond circuits to substrates.

With this new approach, circuits are first formed on a semiconductor wafer using conventional wafer processing techniques.

Then a special wet etching chemical process slices chips off the surface of the host wafer. The chips can range in size from 10 to 100 times thinner than the wafer depending on the application.

'We're unaware of anyone who has sliced them in this way for the purpose of electronics,' said one of the developers, Prof John Rogers of the University of Illinois.

A silicone rubber stamp picks up the chips and bonds them to a substrate coated with a thin polymer adhesive, which is used in conventional electronics.