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MicroLED could soon replace OLED screens, and Samsung's first in line to try

MicroLED could oust OLED as the next big display technology, but it won't be easy. Here's what's behind the technology powering Samsung's modular screens.

Samsung First Look CES 2020

Samsung says it's ready to roll out large-scale production on MicroLED TVs, like this one on display at the company's CES booth, starting in 2020.

Sarah Tew/CNET

For the third year in a row, Samsung has wowed the crowds at CES with a wall-size TV to demonstrate an emerging technology called MicroLED, which uses millions of tiny LEDs to improve on the advantages of OLED (blacker blacks, higher contrast levels) without OLED's limitations (specifically, OLED's tendency for burn-in). 

At a staggering 292 inches -- that's over 24 feet -- the newest version of The Wall, as Samsung calls it, is absolutely gigantic, but it's not the only impressively big screen on display at CES this year. Only slightly more realistically sized for home installation, Samsung's 150-inch 8K screen is essentially a doubled-up version of last year's 75-inch MicroLED TV prototype, which the company began selling alongside custom-built 146-, 219- and 292-inch models last summer.

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The difference this year, however, is that Samsung now says it's poised to go into large-scale production of MicroLED screens up to 150 inches, which would open up the consumer market for MicroLED displays.

So, what makes MicroLED special? 

It's set to replace OLED, which debuted in TVs on the Sony XEL-1 in 2008 and now dominates the TV picture quality race as well as powering most high-end smartphones. But even today the vast majority of screens, from TVs to laptops to tablets to phones, use older LCD technology instead of OLED. It has taken years for OLED to become more mainstream, and you should expect a similarly long path for MicroLED. In other words, don't expect to be able to afford a MicroLED TV anytime soon.

Samsung was the first to take MicroLED to market, but it's not the only one in the game. LG is working on MicroLED, too, and showed a demo panel at the IFA show in Berlin last year, while Chinese TV giant TCL had a MicroLED TV in its booth at CES 2019. Sony has been working on some variation of direct LED TVs since as early as 2012, and both it and Samsung showed similar technology for movie theaters and other huge-screen commercial uses.

Samsung First Look CES 2020

CNET Senior Managing Editor David Katzmaier reports from inside the Samsung booth at CES 2020, where the TV manufacturer is showing off its supersized MicroLED screens. 

Sarah Tew/CNET

The tech could also light up tiny screens. Apple currently uses OLED displays for the high-end iPhones and the Apple Watch, but it's reportedly developing its own in-house MicroLED displays for use in mobile devices, starting with the watch. Details are scarce and it'll likely be years (if ever) before Apple brings it to market, but Cupertino's interest provides further evidence that MicroLED could be big.

It's easy to see why. MicroLED has the potential for the same perfect black levels as OLED with no danger of burn-in. It can deliver higher brightness than any current display technology, wide-gamut excellent color and doesn't suffer the viewing angle and uniformity issues of LCD

Right now the issue with MicroLED isn't image quality, it's manufacturing. The sources cited in the Apple report say the screens are more difficult to produce than OLED displays, to the extent that Apple almost pulled out of development a year ago. 

In 2018 Samsung engineers told CNET's David Katzmaier that the current focus was on making a 4K-resolution MicroLED TV that's smaller than 146 inches, which is exactly what Samsung did a year later. Here's why that's so challenging.

Tiny, tiny LEDs

As the name suggests, MicroLED is made of millions of micro, well, LEDs. Tinier versions of what's in your current LCD TV, or newer flashlights, light bulbs and what myriad other devices use to create light. This makes MicroLED seem simple. So why did it take so long just to make smaller LEDs and stick them in a TV?

Turns out that process is a lot harder than it sounds. One problem is that when you shrink LEDs, the total amount of light they produce goes down. So you either need to drive them harder or increase their efficiency, or both. Just driving them harder introduces new issues. The TV will need a lot more electricity and have to dissipate a lot more heat.

microled-vs-led

An illustration of the size difference between traditional LEDs and MicroLEDs. 

Trendforce

Shrinking the gap between the pixels, or the "pitch size," is another huge challenge. The circuitry and other necessary elements can only get so small. If you can't reduce the pitch size, there's a limit to how small a MicroLED TV can be. Hence how impressive Samsung's smaller MicroLED is. 

Sure, wall-size TVs are cool, but no one will buy them. If a manufacturer wants to make a profit on its new tech, it needs something easy to make in the 50-inch range, or smaller. Once it can do that, the big sizes will be easy. Well, easier.

And then there's the cost. Instead of a handful, or maybe a few dozen, yellow-blue "white" LEDs like you get on a normal TV, you have 8.3 million LEDs, one for each pixel on a 4K 3,840x2,160-pixel display. Actually, it's way worse than that. Since you need red, green and blue LEDs for each pixel, that means there are nearly 25 million total LEDs. Thousands of these are then grouped in modules, and multiple modules make up a TV, wall or movie screen. 

lcd-vs-oled-vs-microled

An illustration of LCD versus OLED versus MicroLED. Compare the complexity and multiple layers of an average LCD versus OLED and especially MicroLED. Also note the thickness, which while not exact, is indicative of the thinner display possibilities of the newer technologies.

Trendforce

Big, big picture

OK, so those are the challenges. Engineers like challenges. And in the history of consumer electronics, the trend is for smaller and more efficient. 

The potential positives are numerous: Brighter images than OLED, but with the same ability to turn off each pixel, for a similarly perfect black. This would mean an even punchier, more realistic image than OLED and better HDR reproduction.

micro-led-rgb

An extreme closeup of the RGB array of a MicroLED pixel. You'll need over 8 million of these for a standard 4K TV. 

Samsung

And remember what I said about smaller and more efficient? Samsung's 146-inch Wall has a pixel size under 1mm. The 75-inch has LED chips in the 0.15mm range.

Samsung is also aiming for higher "luminance efficiency" than other display techs. That's a measure of how much light it creates for a given amount of electricity. Now, this doesn't necessarily mean it will be overall more efficient than, for example, an edge-lit LED LCD, it just means it will be more efficient than that TV if both TVs are creating, say, 2,000 lumens.

Because this will be a "real" LED TV and not the "fake" LED TVs we've had for years (which is to say: LCD panels with LED backlights), all the negatives of LCDs are gone. This means, in theory, we'll be able to enjoy wider viewing angles and less or no motion blur. They shouldn't suffer from image retention or burn-in either. And we may be able to expect longer lifespans than LCD or OLED TVs currently have.

The modularity of MicroLED makes it a bit easier to scale the size of the displays, too. To oversimplify, say a 50-inch TV has 10 modules with around 830,000 pixels on each module. Put more of those same modules together, and a company could sell an 8K, 100-inch TV for essentially no difference in production costs. Same production cost, plus a higher retail price? Companies love that stuff. 

20180109-092004

On the bottom is a MicroLED panel, and the top a tablet showing a mangnified section that reveals the LEDs.

David Katzmaier/CNET

This oversimplifies the whole thing a bit, but that's the general idea. With the right processing, it wouldn't matter if your TV is exactly 4K resolution, or if it's 5,327x2,997 or 8,000x4,500 pixels. If your dream is a wall-size display with 10K resolution, this could be the way to get it. 

To put it another way, current LCD and OLED TVs have different size pixels for different screen sizes. So a 4K 75-inch LCD has larger pixels, but the same number, as a 4K 50-inch LCD. MicroLED could, possibly, just add more pixels of the same size to make a larger, and higher resolution, TV. This could turn out easier, from a manufacturing standpoint, than changing the tiny LED pixel sizes. We'll have to wait and see if it happens that way.

There's also a potential tie-in with the other futuristic TV tech: Quantum dots. Instead of red, green, and blue LEDs, it's possible, perhaps even likely, that it will be almost 25 million blue LEDs, with two-thirds of them sporting either red or green quantum dots. Why? Easier to produce, better efficiency, and doesn't "Micro Quantum Dot LED" just sound cool?

Still a couple years away, at least

Though you can order a Wall now, it's still way too expensive for most people. The 75-inch version might be cheaper, but it's not available yet, and Samsung hasn't said anything about when it might go on sale. Maybe next year, and it will also be super expensive. Maybe we'll see MicroLED in a phone or smartwatch in the same timeframe, since those don't require as many LEDs, don't need to be as bright, and are only expected to last a few years. We shall see.

So MicroLED is future tech, for sure, but it'd be fair to say "near future." The biggest companies in technology hardware are moving forward with the idea. OLED is amazing, but it seems LG is still the only one who can make TV sizes profitable. Their competitors are certainly going to want to find the "next big thing." Or small, as the case may be.

Originally published in March 2018.