Earlier this week, supply chain analyst extraordinaire Ming-Chi Kuo suggested that Apple is looking into e-ink displays for future foldable iPhones. Now, Apple surely researches a lot of things, and most of them never cross the finish line to become actual products.
But as a long-time fan of E Ink as a technology, I’m excited about the possibility that Apple may use it in future devices. E Ink is a niche technology with some very real limitations, but it also has great advantages.
What is electronic ink?
E Ink is a display technology that is fundamentally different from LCD, OLED, and other display technologies. It works by using electricity to attach tiny capsules of pigment to show or hide. The result is a surface that works more or less like traditional ink on paper, hence the name.
Since an e-ink screen only uses power when the screen is being rewritten, it’s ideal for applications where the screen doesn’t refresh very often. Most people are familiar with the E Ink screens of e-readers like Amazon’s Kindle and Rakuten’s Kobo. These devices can have very long battery life because they typically only use battery power when you turn the page.
E Ink also appears in a few other places. There’s a lot of digital signage (think price tags on supermarket shelves) that’s starting to use E Ink, another case where the text stays fixed most of the time, so there’s very little energy consumption. (My favorite E Ink project might be this one that looks like a flattened original Mac.)
I like E Ink because it is easier on the eyes and feels natural in natural light. However, the technology has many drawbacks that have led to its not being widely used. For starters, it doesn’t emit light. In sunlight, e-ink screens are flawless, but in the dark they are unreadable. (To compensate, most e-readers now come with a built-in ring of LED lights around the screen.)
Worse is the slow refresh rate of e-ink screens. The refresh rate has increased over time (on the latest-gen screens, it’s now 350 milliseconds), but it’s nothing like the blazing-fast refresh rates found on computer screens. That means it’s inappropriate for animation, video, and pretty much any interface designed for quick animations. (I reviewed an Android E Ink tablet last year, and trying to use the Android interface at such a low refresh rate was painful.)
E Ink displays also don’t offer the ultra-high resolutions of modern Apple displays. And while E Ink displays have started to support color (after years of only supporting shades of gray), the quality is only now up to scratch and refresh rates are still pretty slow.
Where Apple could use E Ink
According to KuoApple is testing E Ink “for future foldable device cover screen and tablet-like apps.” It makes sense. Foldable devices typically fold inward to protect their screens, leaving an outer surface devoid of information. To counter that, phone makers have been adding add-on “external screens” to do things like show the time and basic information widgets, while others have full-size OLED screens that obviously eat up a lot of battery.
Due to its ultra-low power profile, an e-ink screen would fit quite well as a cover screen. (Think of how Apple Watch’s always-on display has a low-power mode that doesn’t refresh the display very often, making things like the second hands disappear to save power.) With an external color e-ink display, Apple could display the time, notifications, and even widgets on a device’s outer screen.
But auxiliary e-ink screens aren’t necessarily just for flip phones. Consider a future MacBook that includes a low-power E Ink display on the outside so you can see notifications and other basic status information without opening it.
E Ink technology could also enable the creation of some interesting accessories, especially when combined with something like the Smart Connector port on the iPad, which can transfer data and supply power. For example, imagine an iPad smart cover that includes an e-ink screen (thanks to reader Adam L. for this idea), to display widgets, status information, and maybe even static app screens, all of which would be visible even with bright light. sunlight. Alternatively, how about an iPhone case that includes an e-ink screen on the back for status widgets?
E Ink will likely never be a mainstream display technology. The world’s OLED and LED/LCD displays deliver unrivaled high resolutions and refresh rates. But there are many niches that E Ink can serve well. I’d love to see Apple implement the unique features of E Ink in some creative way.