E ink, or electronic ink, is the technology behind e-readers like Amazon’s Kindle and the Yotaphone. It’s a display medium that’s chemically similar to the pigments used in the printing industry, but instead of being deposited on paper, it takes the form of tiny capsules that are about the diameter of a human hair. These capsules contain white and black pigments that are separated by a transparent fluid and sandwiched between two electrodes.
So, how does it work? Applying a negative charge to the bottom of the capsule repels the black pigment, forcing it to the top and making it visible on the screen as a darkened area. Reversing that action by applying a positive charge switches the positions of the particles, creating a white area. The technology can even bifurcate the charge for still sharper results.
While ePaper displays only support monochrome or very limited color options, Ian Corporation, the company behind E ink, has plenty of reasons for why ePaper exists at all—especially given today’s super sharp AMOLED and LCD screens, which kick out 16 million colors or more at densities sometimes higher than 500 pixels per inch.
One reason is power consumption. In our mobile-focused world, where almost all smartphones and tablets struggle with poor battery life, e-ink technology is only using power if it’s changing state. When it’s just showing a static page, it’s not consuming any energy at all.
The tendency of the display to remain static in its inert state also makes e-ink panels ideal for decorations, whether they’re integrated into the device or added on via a third-party accessory. Finally, the reflective nature of E ink eliminates the need for a backlight in brightly lit environments, and the durability of the panels makes for a very rugged display.
These factors combined make for an outstanding reading experience on a portable, durable device, which plays a big part in the enduring popularity of the Kindle and other e-readers. E ink is also used to make changeable retail price tags, oversized wall clocks, and cabinet lock readouts for supermarket divider advertisements, among other applications.
Despite today’s high-density screens, ePaper continues to find new uses in specific applications, according to Ian Corporation. During a product tour, the company showcased oversized presentation tablets for the enterprise, undersized wearables for the fitness-focused, and more. While the more traditional displays of the world are certainly in no danger from E ink—at least in the mobile space—electronic paper is at its best when supplementing more conventional screens in specific applications.
Given the sense of momentum from Ian Corporation, the most interesting developments in ePaper are probably yet to come.