• The researchers placed the component which makes the material electrically conductive underneath the pixelated nanostructure that reproduces the colours – instead of above it, as was previously the case.
• To make the reflective screens, certain rare metals are required – such as gold and platinum.

The Chalmers University of Technology of Sweden has developed a new type of reflective screen that offers optimal colour display while using ambient light to keep energy consumption to a minimum.

The researchers had previously succeeded in developing an ultra-thin and flexible material that reproduces all the colours an LED screen can display while requiring only a tenth of the energy that s standard tablet PC consumes.

But in the earlier design, the colours on the reflective screen did not display with optimal quality.

Using a previously researched, porous and nanostructured material, containing tungsten trioxide, gold and platinum, they tried a new tactic – inverting the design in such a way as to allow the colours to appear much more accurately on the screen.

The digital screen, as thin as paper, sometimes is described as ‘electronic paper’, can not only be used for smartphones and tablets but could also be useful for outdoor advertising, offering energy and resource savings compared with both printed posters or moving digital screens.

Traditional digital screens use a backlight to illuminate the text or images displayed upon them.

This is fine indoors, but we’ve all experienced the difficulties of viewing such screens in bright sunshine.

Real breakthrough

Reflective screens, however, attempt to use the ambient light, mimicking the way our eyes respond to the natural paper.

“For reflective screens to compete with the energy-intensive digital screens that we use today, images and colours must be reproduced with the same high quality. That will be the real breakthrough. Our research now shows how the technology can be optimised, making it attractive for commercial use,” Marika Gugole, Doctoral Student at the Department of Chemistry and Chemical Engineering at the Chalmers University of Technology, said.

The researchers inverted the design for top quality colour production by placing the component which makes the material electrically conductive underneath the pixelated nanostructure that reproduces the colours – instead of above it, as was previously the case.

This new design means you look directly at the pixelated surface, therefore seeing the colours much more clearly.

In addition to the minimal energy consumption, reflective screens have other advantages. For example, they are much less tiring for the eyes compared to looking at a regular screen.

Sustainable and energy-saving solutions

To make these reflective screens, certain rare metals are required – such as gold and platinum – but because the final product is so thin, the amounts needed are very small.

The researchers have high hopes that eventually, it will be possible to significantly reduce the quantities needed for production.

“Our main goal when developing these reflective screens 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,” research leader Andreas Dahlin, Professor at the Department of Chemistry and Chemical Engineering at Chalmers, said.

 Reflective screens are already available in some tablets today, but they only display the colours black and white well, which limits their use.

“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 said.