The M1 chipset. Loads of RAM. 5G. Thunderbolt support. All of these help make Apple’s new, 12.9-inch iPad Pro an almost startlingly capable tablet, one that seems well-equipped to compete against more traditional laptops. (Well, apart from iPadOS’s limitations, anyway.) But if there's one area where the iPad Pro clearly outshines the rest of Apple’s portable computers, it's the tablet's brand new screen.
To learn a little more about what it took to build the Liquid Retina XDR screen, Engadget spoke to Vincent Gu, a senior engineering manager for Apple displays, and iPad marketing spokesperson Scott Broderick, who was quick to claim it is "the absolute best display we could put in the 12.9-inch iPad Pro,” Broderick said.
While some could justifiably argue that an OLED display like those seen in Apple’s iPhone 12 series might be even more impressive, Broderick has a point: this is one damned-good-looking screen.
But first, we should break down that name. As I mentioned in our iPad Pro review, the “liquid” bit refers to the fact that this is actually an LCD screen, which — unlike the OLED displays found in newer iPhones and other high-end mobile devices — relies on a bevy of small backlights to actually make the screen visible. “Retina” is a bit of classic Apple marketing fluff, which the company has used to refer to its mobile displays since the days of the iPhone 4. And the “XDR” part isn't just meant to evoke images of Apple's expensive, high-end monitors — it refers to the display's "extreme" dynamic range.
Ultimately, what makes this display so appealing isn’t its size — it’s the same 12.9 inches as before — or the fact that it refreshes at 120Hz. No, it’s all because of a component you can’t even directly see: a new backlighting system composed of more than 10,000 super-small LEDs, divided up into 2,596 local dimming zones. (In case you were keeping count, Apple’s $5,000, 6K Pro Display XDR monitor only has 576 dimming zones.)
The idea is pretty simple: by making those light sources smaller, Apple could fit more of them behind the rest of the LCD panel's many layers, allowing for more precise control over what parts of the screen are lit up in any given moment. It’s a pretty standard concept in the TV world, with TCL, Samsung, and LG each with their own confusingly branded version. For what it’s worth, though, Apple insists that its own mini-LED backlighting system was designed completely in-house.
“The mini LEDs we put into Liquid Retina XDR is a truly custom-designed, Apple-proprietary technology,” said Gu, who noted that they were more than a hundred times smaller than those used in last year’s iPad Pro. To no one’s surprise, carefully arranging those thousands of LEDs was a crucial hurdle, one Apple only managed to clear thanks to engineers who custom-designed manufacturing equipment and created their own special solder.
“We had to deliver specific equipment to be able to put these over 10,000 mini LEDs into place with such precision that didn’t exist prior to us,” said iPad spokesperson Broderick. (That said, Apple declined to tell us exactly how small each individual mini LED measures, or how long it takes to produce a single Liquid Retina XDR screen.)
Beyond the lighting system, Gu also said the switch to mini LEDs required Apple to re-engineer core components of its display stack, including the optical films and diffusers that help control the flow of light and distribute it evenly across the entire panel. And then, Apple’s design and manufacturing engineers had to take that new, physically larger screen package and bake it into a kind of device that has been synonymous with portability. In other words, the whole process was... sort of a pain.
It's a good thing for the company's engineers, then, that the mini-LED screen is said to remain a key part of the iPad Pro experience for a while. But that's not to say other changes aren't in the offing. Apple analyst Ming-Chi Kuo suggested in a recent note that Apple could shift to using OLED displays — which are known for their deep blacks and extremely vivid colors — in the iPad Air as early as next year. (For what it's worth, Broderick and Gu wouldn't confirm whether Apple had contemplated using OLED panels in the iPad Pro)