Gustav Klimt Kiss displayed on an iPhone (left), which houses a small e-paper display with the same image (right)
Kingston Frameworks; Kunli Xiong et al (2025)
A new type of color e-paper can display vibrant, full-color, high-resolution images and video while consuming minimal power, indicating a possible future for display devices.
While traditional LED screens emit red, green and blue light to create color, e-paper screens use tiny molecules to create images. Until recently, these devices were limited to black and white screens, but color screens are now available. However, they struggle to update quickly enough to display video.
To solve this problem, Kunli Xiong from Uppsala University, Sweden, and his colleagues have developed electronic paper with pixels made from tungsten oxide nanodisks. Each pixel is about 560 nanometers in size, giving the paper a resolution of 25,000 pixels per inch (PPI). In contrast, smartphones usually have PPIs in the hundreds.
The tungsten oxide nanodisks have slightly different sizes and spacing, so each reflects a specific band of light. By connecting them together, different colors can be presented, and the brightness can be changed using a short electrical pulse that forces the ion inside the disk. Once the color is set, the ions remain in place and the color is maintained without constant power.
The researchers created an e-paper display measuring just 1.9 by 1.4 millimeters, about 1/4000 the size of a typical smartphone display, and used it to display a 4,300-by-700-pixel image of Gustav Klimt. Kiss – extremely high resolution for such a small device. It can also update approximately every 40 milliseconds, which is fast enough to display video.
Another advantage of the new e-paper is its incredibly low power consumption, says Xiong. The display consumes about 1.7 milliwatts per square centimeter when displaying video and about 0.5 milliwatts per square centimeter for still images.
“What I like about this work is that it's fast enough to support video while keeping power consumption to a minimum. This is because once you switch items, they stay on without having to refresh them,” says Jeremy Baumberg at Cambridge University.
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