Colors of electronic paper approach LCD display technology

Electronic paper, from companies like E Ink, can display full color images now while minimizing energy consumption. The trade-off is they don’t look anywhere almost as dynamic as display technologies like LCD and OLED, but new research outside Sweden could soon change that with a reflective screen type.

Over the past year, we have seen more e-readers and e-note devices adopt E Ink Kaleido color e-paper display technology. Like an Amazon Kindle or a Kobo Rakuten, devices produce text and images that resemble a printed page, but now in color, although the quality of color reproduction is poor compared to LCD and OLED displays. Even the LCD screen of a cheap tablet or smartphone can reproduce over 16 million different colors, but E Ink’s Kaleido displays are limited to just 4,096 colors, and therefore, images tend to appear desaturated on electronic color paper devices.

E Ink continues to improve its Kaleido electronic paper technology, and there are already devices using Kaleido 2 screens, but researchers at Chalmers University of Technology in Sweden seem to have moved ahead of the electronic color paper currently available in consumer gadgets. In 2016, researchers at the school created a material less than a micrometer thick, as flexible as paper and capable of reproducing as many colors as an LCD screen. But unlike LCD screens, the material was not illuminated and instead reflected ambient light in in the same way as screens in e-readers. Not only does it have the appearance of paper (which may be more pleasing to the eyes), its creators also discovered that the material could be used as a screen while requiring about a tenth of the amount of energy a device has. like the Amazon Kindle needs.

Almost five years later, in a new study published in the journal Nano letters, the researchers detail how they improved the material with a relatively simple change: overturning its structure. The material is composed of several layers, including a “porous and nanostructured material, containing tungsten trioxide, gold and platinum” which produces different colors by reflecting light, and a layer which adds electrical conductivity so that, like an LCD screen, the colors can be continuously refreshed and changed. Previously, the conductive layer was on top of the color nanostructure, but it has now been moved below, improving the accuracy and fidelity of colors as seen by the human eye.

Researchers admit there are challenges in mass producing their potential revolutionary display technology. The ingredients for E Ink’s screens aren’t very expensive, which means you can get an e-reader for under $ 100. But with ingredients like gold and platinum needed to make the new display technology, even at thicknesses of just 20 nanometers, large-scale manufacturing could result in higher prices for products incorporating them. It remains to be seen whether the savings from reduced power consumption would help offset display costs, as that means tablets, smartphones, and e-readers could be shipped with much smaller batteries. Researchers could also eventually find a cheaper substitute for these rare materials.