Retina E-Paper Design Could Boost E-Ink Displays to 4K and Higher

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Researchers from Uppsala University and the University of Gothenburg have developed a new type of e-paper pixel that can be as small as 560 nanometers—a fraction of the size of even micro-OLED diodes, which are among the smallest options available to display manufacturers.

As TechSpot reports, this could enable pixel densities in the thousands of pixels per square inch, far more detailed than even the best modern display. It could unlock a whole new range of e-book readers and similarly easy-on-the-eye displays for all kinds of purposes.

The greatest strengths of E-Ink displays are their low power consumption and ease of viewing. They’re typically far more comfortable to stare at for long periods than traditional display types, but they just can’t match LCD or OLED in terms of contrast, color, and detail. But researchers may have solved at least part of that problem. The new anti-glare display type could deliver significantly higher pixel densities, potentially allowing incredibly detailed images to be displayed at lower power and with greater care for eye comfort, and much more besides.

Building “Retina E-Paper” pixels involves injecting “tungsten trioxide nanodisks through a reversible insulator-to-metal transition on electrical reduction,” according to the proposal. This enables the creation of pixels that are approximately 560 nanometers across, as opposed to the five-micrometer diameter of even micro-OLED pixels.

Retina E-Ink display technology.

(Credit: Nature)

Modern smartphones have pixel densities ranging from 300 to 500 pixels per inch. These new Retina E-Paper pixels could be crammed into a device at 25,000ppi, allowing for super-detailed e-paper phones, monitors, and even TVs. It also raises the prospect of even smaller, yet still detailed displays, such as those in smart glasses or even on a smart contact lens.

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The new display technology doesn’t sacrifice E-Ink’s usual strengths, either. They would have strong contrast and visibility when in direct sunlight—much better than traditional LCDs backlit by LEDs, and they use far less power, too. Indeed, researchers believe they can get the power use down to just 0.5 milliwatts per square centimeter with static images, or up to 1.7 milliwatts per square centimeter for video. That’s far less than even the E-Ink displays we have today.

There are still downsides, though. It’s not possible to deliver color in the same way as LCD or OLED, and it is currently limited to 25Hz refresh rates. It’s also still a proof-of-concept technology, so it’s unlikely to replace your gaming monitor anytime soon.