E-paper (Electronic Paper) displays are fascinating as they mimic the appearance of ordinary ink on paper. These displays make reading comfortable and provide a wider viewing angle than most light-emitting displays. A very high quality e-paper display can be viewed in direct sunlight without the image appearing to fade. These screens appear life-like and resemble the physical paper reducing eye strain. The power consumption of these displays, moreover, is very low as compared to traditional displays.
E-paper displays differ from other traditional displays like LCD as they reflect like paper instead of emitting light. E-paper displays consist of millions of miniscule capsules filled with a clear fluid containing microscopic particles of different colors and electrical charges. When an electric field is applied, the electrodes located above and below move in a certain direction, which makes the surface of the display reflect a certain color. The electronic displays are bi-stable, which means no power is required to retain an image.
Traditional displays use backlight for illuminating texts and images. These displays work fine indoors but it is difficult to view them in bright sunlight. Reflective screens, on the other hand, use the ambient light, mimicking the way our eyes respond to natural paper.
Researchers at the Chalmers University of Technology have developed an e-paper display that displays colors with optimal quality. The researchers have previously demonstrated an ultra-thin, flexible material that reproduces all the colors an LED screen can display, while requiring only a tenth of the energy that a standard tablet consumes. This earlier design, however, does not display colors with an optimal quality. The newly developed display uses a previously researched, porous and nanostructured material, containing tungsten trioxide, gold and platinum. In the new display, they inverted the design in such a way as to allow the colors to appear much more accurately on the screen.
In this inverted design, they placed a component which makes the material electrically conductive underneath the pixelated nanostructure, instead of above it, reproducing the colors. This new design allows you to look directly on the pixelated surface.
“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, professor at the Department of Chemistry and Chemical Engineering at Chalmers.
The technology developed by the Chalmers University researchers depends on the material’s ability to regulate how light is absorbed and reflected. The material underneath the nanostructure conducts electronic signals throughout the screen and can be patterned to create high-resolution images.
More information regarding the research can be found at http://dx.doi.org/10.1021/acs.nanolett.1c00904.