e-Ink iPhone display could combine Apple quality with near-zero impact on battery life

A report this morning says that we may see in the future an e-Ink iPhone display, as a secondary screen on a folding iPhone.

The most likely interpretation of a follow-up tweet is that Apple is testing a type of color e-ink display that offers crisper text, brighter displays, and richer colors than conventional technology …


e-Ink or ePaper displays are best known for their use in Amazon Kindles, and other ebook readers. They are designed to combine the benefits of paper-like appearance with extremely low power consumption.

The first generations of e-ink displays were mono – black on white, or vice-versa – but color is now supported.

The main drawback of e-Ink displays is a very slow refresh. This is acceptable for ebook usage, when you’re only going to be “turning the page” every 30 seconds or so, but not suitable for the type of dynamic usage needed for things like the primary displays of smartphones or laptops (even if one company disagrees). However, they can be suitable for secondary displays, with less dynamic content.

How might an e-Ink iPhone display be used?

Apple analyst Ming-Chi Kuo said that Apple’s interest is for foldable devices. The company is expected to launch a folding iPhone at some point, which typically calls for a secondary display visible while the device is folded. Typical uses for this are to display the time, and notifications.

Existing folding smartphones use OLED for their external displays, but it would make a lot of sense to use an e-Ink one. The type of content displayed on a secondary display doesn’t change often, making the refresh rate unimportant. Typically, a user will only look at the display to quickly check the time, or to view a notification after an alert.

The big advantage of this is that the secondary display would use only a trickle of battery power, compared to even the type of low-refresh rate OLED used for the always-on feature of recent and current Apple Watches.

What e-Ink tech might Apple use?

While e-Ink and ePaper are used as generic terms for this type of display, Kuo said in a follow-up tweet that he was referring to a specific company.

The company offers a display module branded Kaleido, and it’s likely that Apple is testing the Plus variant.

Kaleido displays offer 16 levels of grayscale and are capable of displaying 4096 colors, enable ultra low power and high mobility devices with a paper-like experience, ideal for image-rich information applications such as charts, graphs, maps, photos, comics and advertising. And just like E Ink’s monochrome ePaper products, Kaleido’s crisp text and detailed color graphics are fully viewable in direct sunlight, and have the same low power attributes […]

The new printing process alleviates the need for a glass-based CFA, making the displays thinner and lighter than previous generations, while simultaneously having higher optical quality […]

In [the Plus] version, we’ve made adjustments to the printed CFA [Color Filter Array], to allow for a better color balance, and printing texture, and we’ve brought the CFA closer to the ink, to reduce light scattering. New image rendering algorithms allow for crisper text. In addition, we have made adjustments to the light guides, allowing for better optimization of the LED color spectrum to minimize color blending.

It would seem that this could offer the display quality we’d expect from an Apple device, coupled to a power draw so negligible that there would be no practical impact on battery life.

Of course, this assumes that a folding iPhone is ever launched – which is not a foregone conclusion.

What are your thoughts? Please let us know in the comments.

Concept image: iOSBetaNews

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Avatar for Ben Lovejoy Ben Lovejoy

Ben Lovejoy is a British technology writer and EU Editor for 9to5Mac. He’s known for his op-eds and diary pieces, exploring his experience of Apple products over time, for a more rounded review. He also writes fiction, with two technothriller novels, a couple of SF shorts and a rom-com!

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