Colour e-paper screen offers high-res video with low energy use
That of Gustav Klimt The kiss displayed on an iPhone (left), on which a small e-paper screen with the same image is placed (right)
Kingston Executives; Kunli Xiong et al. (2025)
A new type of color electronic paper can present bright, high-resolution, full-color images and videos while consuming minimal power, paving the way for a possible future for display devices.
While traditional LED displays emit red, green and blue light to produce color, e-paper displays use tiny molecules to create images. Until recently, these devices were limited to black and white, but color screens are now available. Yet they struggle to refresh quickly enough to display the video.
To solve this problem, Kunli Xiong of Uppsala University, Sweden, and colleagues developed e-paper with pixels made from tungsten oxide nanodisks. Each pixel measures approximately 560 nanometers, giving the paper a resolution of 25,000 pixels per inch (PPI). In contrast, smartphones generally have a PPI of several hundred.
The tungsten oxide nanodiscs are made with slightly different sizes and spacings, so each reflects a particular band of light. By placing them together, it is possible to present a range of colors, and the brightness can be changed by a brief electrical pulse that places an ion inside the disk. Once a color is set, the ions stay in place and the color holds without continuous feeding.
The researchers created an e-paper screen measuring just 1.9 millimeters by 1.4 millimeters, or about 1/4,000th the area of a normal smartphone screen, and used it to display a 4,300 x 700 pixel crop of Gustav Klimt’s work. The kiss – extremely high resolution for such a small device. It can also refresh approximately every 40 milliseconds, which is fast enough to display a video.
Another advantage of the new e-paper is its incredibly low power consumption, says Xiong. The display uses about 1.7 milliwatts per square centimeter for displaying videos and about 0.5 milliwatts per square centimeter for still images.
“What I like about this work is that it’s both fast enough to support video, while minimizing power consumption. That’s because once things are switched, they stay switched without having to refresh them,” says Jeremy Baumberg of the University of Cambridge.
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