Engineering news
The reflective screens, which could cut the energy consumption of smart phones, tablets and other technology, were developed at Chalmers University of Technology in Sweden.
Traditional digital screens use backlights to illuminate the text or images displayed upon them. This works well indoors, but struggles in bright sunlight.
Reflective screens instead use the ambient light, which lights up the page and reflects in the same way as it does from conventional 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," said doctoral student Marika Gugole.
The researchers had previously succeeded in developing an ultra-thin, flexible material that reproduces all the colours an LED screen can display, while requiring only a tenth of the energy that a standard tablet consumes.
In the earlier design the colours did not display with optimal quality, however. In the new research, the team used a porous and nanostructured material containing tungsten trioxide, gold and platinum to invert the design, allowing the colours to appear much more accurately.
The researchers placed the component that makes the material electrically conductive underneath the pixelated nanostructure that reproduces the colours, instead of above it. The new design means users look directly at the pixelated surface, therefore seeing the colours much more clearly.
In addition to the minimal energy consumption, electronic paper is also much less tiring for the eyes compared to regular screens.
The team said that only ‘very small’ amounts of rare metals are needed, but they hope to reduce that further.
"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," said research leader Professor Andreas Dahlin.
"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," he added.
In addition to smart phones and tablets, the technology could also be useful for outdoor advertising, offering energy and resource savings compared with printed posters or digital screens.
The research was published in Nano Letters.
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