he day you can enjoy a relaxing soak in the bath, reading an unrolled copy of an electronic newspaper, may not be far off. This scenario may be realised by means of an ingenious combination of polymer and electronics technology that allows creation of flexible displays.

Sir Richard Friend, Cavendish Professor of Physics, Optoelectronics Group at the University of Cambridge, UK, believes that electronic circuits based on polymer transistors are realisable and expects products based on the technology to come onto the market in less than five years' time.

His Cambridge team found in 1989 that passing an electric current through certain polymers made them emit light. The group formed Cambridge Display Technology (CDT) in 1992 to commercialise its patented light emitting polymer (LEP) technology derived from this discovery. It also earned Friend and his colleagues €700,000 of a €1million European Union Descartes research prize in 2003. In developing the polymer light-emitting diode (PLED) display project, they aimed to construct a technology replacing deposited-glass or silicon-backed displays with flexible plastic substrates, allowing cheaper processing.

As an alternative to emissive flexible PLED displays, a form of organic light emitting diodes (OLEDs), the "electronic paper" is particularly suitable for displaying text and static images in reflected light. Friend is also developing the core plastic electronics circuitry at Plastic Logic, his second spinoff company, which will enable such display devices to take off. US firm E Ink uses electrophoresis for such a display device almost like ink on paper, is easy to read in reflective light and flexible. It works by generating images by means of thousands of miniscule capsules the width of a human hair. Black and white particles inside can be switched back and forth via a small electric voltage to display images.

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