‘Electronic paper’ brings vibrant colors to ultra-thin digital screens

GOTHENBURG, Sweden — Digital technology seemingly gets smaller and thinner every year. Now, researchers from Chalmers University of Technology say people may soon be reading from digital screens as thin as a sheet of paper. Moreover, their report reveals how this “electronic paper” will have vibrant colors that users will still be able to see while sitting in the sun.

Traditional electronic screens use a backlight to illuminate the text and pictures in the display. While this works well indoors, taking a digital screen outside on a sunny day can leave users unable to see anything. Researchers say a new type of reflective screen that they call “electronic paper” uses ambient light to reduce energy consumption and glare. This technology also mimics the way a person’s eyes respond to looking at natural paper.

“For reflective screens to compete with the energy-intensive digital screens that we use today, images and colors must be reproduced with the same high quality. That will be the real breakthrough. Our research now shows how the technology can be optimized, making it attractive for commercial use,” says Marika Gugole, a doctoral student in the Department of Chemistry and Chemical Engineering, in a university release.

The Chalmers team had previously created an ultra-thin and flexible material that displays all the colors of an LED screen. This screen also only needed a tenth of the energy that a regular tablet does. Unfortunately, this early reflective model couldn’t display colors with any real quality.

The new electronic paper uses tungsten trioxide, gold, and platinum as its core materials. Additionally, scientists also inverted their original design, which they say allows colors to shine through more accurately on the screen.

Turning the design for electronic paper upside-down

Researchers placed the component that makes their paper-like product electrically conductive underneath the pixelated nanostructure that creates colors. Typically, designers put this component above it, just as their older design did as well.

The result means users look directly at the pixelated surface and see colors much clearer than on a normal tablet. This design also needs much less energy to keep it running. The team adds their design has a less tiring effect on the eyes, which is common among devices which emit potentially-harmful blue light.

While using gold and platinum may sound really expensive, study authors note the final product is so thin, electronic paper would only need a very small amount of these precious metals to operate.

“Our main goal when developing these reflective screens, or ‘electronic paper’ as it is sometimes termed, is to find sustainable, energy-saving solutions. And in this case, energy consumption is almost zero because we simply use the ambient light of the surroundings,” explains research leader Andreas Dahlin.

Although flexible and reflective screens are already available today, the team says they only do a good job of showing black and white images.

“A large industrial player with the right technical competence could, in principle, start developing a product with the new technology within a couple of months,” Dahlin adds.

The study appears in the journal Nano Letters.