"It's the closest thing demonstrated today to electronic paper," Yu Chen, an electrical engineer at E Ink and a visiting scientist at Princeton University in New Jersey, told Reuters.

When it is fully developed e-paper will be able to display black and white and colour text using wireless technology.

Buying the daily newspaper will no longer be necessary because with e-paper it will be updated wirelessly or through the Internet.

"In the current form you can already receive images and read books through these displays screens," Chen said but he added the display was still too slow for a video display because of the switching speed of the electronic ink.

The display consists of two components. The front part switches according to electronic signals and the back component is a circuit made of transistors that control each individual pixel that composes the display.

Each pixel needs a circuit, made of transistors, behind it to switch it. In order to make electronic paper the transistors have to be made on a very thin and flexible substrate.

"In our case it is a very thin stainless steel foil. You need to put a layer of electronic circuits on that foil," Chen said.

Chen, who reported the research in the science journal Nature, said the size can vary from a business card to a computer screen. The current device is too thick to be folded in half but Chen and his team are working on a thinner a version.

"Our work demonstrated that you can make high-quality electronic circuits on very thin and flexible substrates," he added.