Swiss researchers have developed video-display technology that can produce an unlimited range of colours. Tiny artificial "muscles" in the display generate different shades by expanding and contracting in response to electricity.

The flexible material allows individual pixels — the dots that make up an image on a screen — to display "every single natural colour," said Manuel Aschwanden, a project researcher and nanotechnology specialist at the Federal Institute of Technology in Zurich.

Swiss scientists say they have developed a video display that uses artificial 'muscles' to create an unlimited range of colours.
(Associated Press)

The design uses an electrically tunable grating that acts like a prism. The millimetre-thick grating is made of the same flexible polymer used to create artificial muscles. By adjusting voltage, the researchers can direct a different colour through a tiny hole in front of the grating.

By contrast, conventional displays rely on small pixels that trick the eye into seeing a colour that is mixed from the three primary colours red, green and blue.

Peter Bryanston-Cross of the Optical Engineering Laboratory at Warwick University, England, said a device based on the new technology "would be a significant achievement," but noted that "there can be a long jump to move from primitive demonstrator to actual new technological displays."

"But it's a very interesting and remarkable achievement, with real potential," said Bryanston-Cross, who was not involved in the Swiss research.

The Zurich team's work, led by Professor Andreas Stemmer and published in the September edition of the scientific journal Optics Letters, poses "a serious challenge to big manufacturers," said Aschwanden. He said it could allow high-end optical equipment such as microscopes to be produced more cheaply and efficiently.

Pure colours

It also promises to significantly increase the screen resolution of conventional computer monitors.

"At the moment most screens achieve three to four pixels per millimeter (75-100 dots per inch). If you look closely enough at the current screens, you can still see the individual pixels. Our system can achieve 16 pixels per millimeter (400 dpi)."

According to Aschwanden, current display technology is limited because screens have to create all colours by combining red, green and blue.

"The problem with normal LCD screens is that they start with just one shade of red. If you want dark red, you need to create that first by mixing the available red with green and blue, and so the colour isn't pure," he said.

"Our screens allow you to define the precise wavelength of the colours you want to combine, and display different shades, such as the colour of the sky or the sea, much more accurately."

The team has been working on the project for about a year and a half, said Aschwanden.

Among the practical problems the Swiss researchers still have to overcome is the large internal voltage required to power the display.

Aschwanden said the team had been contacted by a number of well-known technology companies, but he refused to divulge names.

The goal, he said, is to produce the new screens within the next 10 years.