MiniLED and microLED displays
The little LEDs that will make a big difference to displays
FANCY CONNECTING YOUR
Apple TV to a 292–inch display? At this year’s CES, Samsung displayed its massive screen, which it calls The Wall. LG also had a 145–inch microLED display. And the same microLED tech is coming to smaller screens — one day, you might even have it in your Apple Watch.
It’s been repeatedly rumored that Apple plans to begin switching from standard LED displays to miniLED ones in the coming year, and it has been granted multiple patents involving even more impressive microLED displays.
Apple’s laptops, iMacs, iPads and Cinema Displays use LED displays, just like most of the big TVs you’ll find in your local audio–visual emporium. It’s a mature technology and it’s absolutely everywhere, but it’s not perfect.
In a normal LED display, the pixels don’t emit their own light. For that, they need LEDs, light–emitting diodes, which emit light when an electrical current is passed through them. The power goes in, the light goes on, the pixel becomes visible. It’s rather like shining a spotlight through a stained glass window, except there are several hundred spotlights shining at several thousand windows.
In standard LED displays the LEDs are usually situated behind or around the edges of the panel, and you can often see flaws as light leaks into the picture around the edges, so blacks are dark greys instead of true blacks. There are various tweaks to minimize the effect, but they can’t get rid of the issue altogether.
Enter OLED, which doesn’t need to be backlit. If you compare the screen on an iPhone that has a Super Retina display or an Apple Watch to the screen of an iMac, iPad or MacBook you’ll see it’s more vivid and the blacks are properly black. That’s because the Super Retina display is OLED.
OLED stands for Organic Light– Emitting Diode, and that means the pixels emit their own light — no backlight required. If a pixel needs to be black, it doesn’t emit any light, so blacks are properly black and colors pop. But OLED displays are really hard to make at large sizes, they can suffer from screen burn, and they’re very expensive.
Wouldn’t it be great if you could get the affordability and scalability of LED with the vivid colors and contrast of OLED? That’s where miniLED and microLED come in…
WITH MINI AND MICROLEDS YOU GET BETTER BRIGHTNESS AND CONTRAST AS YOU’VE GOT MORE LEDS TO ADJUST
MINI, MICRO, O& Q
miniLED will be used mainly to improve existing LED displays, while microLED will be a rival to OLED. miniLEDs are similar to the LEDs in existing displays’ backlights but they’re 80% smaller. That means you can put many, many more miniLEDs into the same space — tens of thousands instead of a few hundred — and that means better brightness and contrast. It’s not quite as good as OLED but it’s close, and cheaper to make, so it’s ideal for devices such as iPads.
microLED is smaller still and more like OLED, as each pixel emits its own light — so there’s no need for a dedicated backlight. Blacks are just as black as they are with OLED, but microLED can deliver higher peak brightness levels, which is important for HDR content. And, so far at least, it seems that the inorganic compounds in microLED don’t degrade like the organic ones in OLEDs do, so they last for many more years.
And microLED scales up. microLED panels have the potential to become significantly thinner than OLED ones, and multiple smaller microLED panels can be stitched together to create one huge big panel. So far the ones we’ve seen have been TV–shaped, but the microLED’s flexibility could lead to all kinds of shapes.
QLED, short for Quantum Dot LED, is a way of improving standard LED displays: It’s in Sony’s Triluminos displays and Samsung’s QLEDs. It uses a thin film of semiconductors, quantum dots, to turn the light from blue LEDs into not just blue but red and green too. It’s more energy– efficient and delivers better color than standard LED. Samsung’s 2020 Galaxy Book Flex and Galaxy Book Ion have quantum dot displays for better screen brightness and improved battery life. Our friends at techradar.com’s first impression of the Book Flex is that it’s “one of the most vibrant laptop displays we’ve ever seen,” but it isn’t high enough resolution. Apple has been experimenting with quantum dots for displays and cameras since at least 2013, but there’s no sign of those experiments making it into any of its products.
THE MICROLED CATCH
Cramming all of those LEDs into such small spaces is a difficult — and costly — business. LED displays are usually made using pick–and–place machines that lift the component, rotate it and put it in the right place on the circuit board. With normal LEDs that means working to an accuracy measured in millimeters; with microLED it’s microns. Newer producing processes look promising but aren’t ready for prime time just yet.
There’s currently a limit to how small you can make a microLED display before the cost of doing so becomes hilarious: Samsung says that while it could make 40–inch displays right now, they’d be so expensive that nobody could afford them.
There’s no doubt that Apple is investing in microLED displays. In 2019 it was awarded multiple patents for microLED displays that could be used in iMacs, MacBooks, iPhones, iPads, and TVs. But the current issues with cost, size and yield won’t be addressed overnight. If nobody can currently make an affordable microLED display that’s smaller than 40 inches, Apple’s not going to launch a microLED Apple Watch in October.
A miniLED iPad is probably imminent but a microLED iPhone or Apple Watch will take longer. We can expect to see a miniLED Cinema Display this year and miniLED MacBooks and iPads by 2021; microLED is a good bit further in the future.