What is that? Super supply chain analyst Ming-Chi Kuo has suggested that Apple investigate E Ink displays for future foldable iPhones. Now, Apple is definitely investigating a lot of things — and most of them never really reach the finish line to become real products.
But as a longtime fan of E Ink as a technology, I’m excited about the possibility that Apple could use it in future devices. E Ink is a niche technology with some very real limitations, but it also has some huge advantages.
What is e-ink?
E Ink is a display technology that is fundamentally different from LCD, OLED, and other display technologies. It works by using electricity to place small capsules of dye to make it visible or hidden. The result is a surface that works more or less like traditional ink on paper, hence the name.
Since the E Ink screen only uses power when the screen is rewritten, it’s great for applications where the screen doesn’t refresh often. Most people know E Ink screens from e-readers such as Amazon’s Kindle and Rakuten’s Kobo. These devices can have a very long battery life because they only use battery power when you turn the page.
E Ink is cropped up on several other sites as well. There are a lot of digital signage (think price tags on supermarket shelves) that are starting to use E Ink – another case where the text stays static most of the time, so there is very little power pull. (My favorite E Ink project might be this one that looks like the original flat Mac.)
I like the E Ink because it’s easier on the eye and feels natural in natural light. However, this technology has so many commitments that it has not been widely used. For starters, it does not emit light. In sunlight, the E Ink screens are flawless, but in the dark, they’re unreadable. (To compensate, most e-readers now come with a built-in ring of LEDs around the screen.)
Even worse are the slow refresh rates of the e-ink screens. The refresh rate has increased over time — it’s now 350 milliseconds on the latest monitors — but it’s nothing like the ultra-fast refresh rates of computer monitors. This means that it is not suitable for animation, video and almost any interface designed for fast animation. (Last year, I reviewed an E Ink Android tablet, and trying to use the Android interface at a low refresh rate was a pain.)
E Ink displays also don’t offer the full resolution of recent Apple displays. And while E Ink displays are starting to support color (after years of only supporting shades of gray), the quality is only now starting to be up to par, and refresh rates are still very slow.
Where Apple may use e-ink
according to KOIn the future, Apple is testing the E Ink “for foldable cover screen and tablet-like applications.” It seems reasonable. Foldable devices generally fold inward to protect their screens – leaving the outside surface free of information. To counter this, phone makers have added additional “external displays” to do things like display the time and basic information tools while others have full-size OLED screens that obviously use up a lot of battery life.
Due to the very low power profile, the E Ink screen will be very suitable for the cover screen. (Think about how the Apple Watch’s always-on display has a low power mode that doesn’t refresh the display very often, making things like the second hand disappear to save power.) With the E Ink external color display, Apple can display the time, notifications, and even widgets on the the external screen of the device.
But the extra E Ink screens aren’t necessarily just for foldable phones. Consider a futuristic MacBook that includes a low-power E Ink display on the outside so you can see notifications and other essential status information without opening it.
The E Ink technology could also allow for some interesting accessories to be created, especially when paired with something like the Smart Connector port on the iPad, which can transfer data and save power. For example, imagine a smart cover for the iPad that includes an e-ink display (shout out to reader Adam L for that idea), to display UI elements, status information, and perhaps even static displays from apps, all of which will be visible even in bright light. Sun light. Alternately, how about an iPhone case that included an E Ink screen on the back of the case widgets?
E Ink will probably never be a mainstream display technology. The world’s OLED and LED/LCD displays offer high resolutions and unbeatable refresh rates. But there are many areas where E Ink can serve you well. I’d like to see Apple spread the unique characteristics of the E Ink in some creative ways.