CES 2021, this year’s fully virtual consumer electronics show, kicked off on Monday with Media Day and a flurry of announcements from the largest consumer electronics manufacturers. For these companies, the center of the consumer electronics world is the television—the bigger the screen the better. People generally don’t replace their TVs as often as they do their mobile devices, so TV manufacturers are constantly looking for a new display technology or feature that will make that TV on the store shelf seem a lot better than the TV in the family room. Some of these efforts have been more successful than others—3D displays, for example, never caught on.
This year, the TV manufacturers’ tech news coalesced around mini-LED technology. LG pitched its “quantum nanocell mini-LED,” a technology it somehow turned into the acronym QNED.
TCL touted its “ODZero” mini-LED.
To understand what mini-LED is—and isn’t—and why it improves the TV picture, it helps to know a bit about what came before it.
First, to be clear, mini-LED isn’t a new display technology so much as a new backlight. The picture itself is generated by a liquid crystal display (LCD); how that evolved is an entirely different story.
Originally, LCD displays were lit by fluorescent tubes running behind the screens. Then, as LEDs became available at mass market prices, they replaced the fluorescent tube and the LCD TV came to be called the LED TV (a misrepresentation that still drives me a little crazy). LED has several advantages over fluorescent tubes, including energy efficiency, size, and the ability to be turned off and on quickly.
The first LED TVs used just dozens of the components, either arrayed on the edges or behind the LCD panel, but the arrays quickly grew in complexity and companies introduced what is called “local dimming.” With this technology (in which groups of LEDs are turned down or even off in the darkest areas of the TV picture), contrast, a big contributor to picture quality, increases significantly.
Recalls Aaron Drew, director of product development for TCL North America: “We were an early proponent of local dimming in the U.S. market. We had the first TV with what we called contrast control zones in 2016. That array had nearly 100 zones with a total number of LEDs in the hundreds.
There is no industry definition of mini-LED. For us, I would say we introduced our first backlight using mini-LEDs, that had just over 25,000 LEDs and nearly 1000 contrast control zones.”
Drew says that he’s happy to see other brands join TCL with mini-LED product announcements, but points out that TCL’s new display technology is interesting not just because it uses mini-LEDs, but because the company has figured out a way to eliminate the need to maintain space between the LEDs and the LCD panel; in traditional designs, he says, a little space is required to allow lenses to distribute the light evenly.
TCL’s latest mini-LED TVs close the gap between the LED backlight and the LCD display Image: TCL
“We have a way to precisely control the distribution of the light without a globe shape lens and optical depth,” Drew says.
And that reduced optical depth (OD) feature gives the TCL technology the “OD Zero” tag.
This latest generation of TCL LED TVs contain tens of thousands of LEDs and thousands of contrast control zones, the company indicated in its announcement.
Over at LG, the Q of its QNED acronym refers to the quantum dot color film that most LED TVs use today to convert some of the blue LED light into the green and red wavelengths used in an RGB picture. The N, for NanoCell, also refers to that quantum dot layer. The company apparently dropped the L from LED to avoid confusion with its OLED TVs.
LG says these QNED TVs will have almost 30,000 LEDs and 2500 local dimming zones.
LG’s new backlight for its LCD displays uses an array of 30,000 mini LEDs Image: LG
None of the mini-LED TV announcements have included pricing to date.
Is mini-LED technology different enough to send the average consumer running to the store to replace a TV they currently own? Without actually seeing these new displays in person—the huge downside of a virtual trade show—it’s impossible to tell. My guess, however, is no. But it is different enough to make a mini-LED TV display look better on a store shelf than a non-mini-LED TV parked next to it, so it’s not surprising that everybody is jumping into this pool.
Yet to come to the consumer market, and likely to make a much bigger difference in picture quality, is the so-called micro-LED. These use LED components that are small enough to act as pixels themselves, not as backlights for an LCD. The upshot: They lose no brightness to filters and can be turned off individually for true blacks—and they actually deserve to be called LED TVs. While some companies have announced micro-LED displays, these are expensive and gigantic—in the over-100-inch screen size category—and aimed at commercial markets only. Samsung did announce a 110-inch micro-LED model at CES 2021 that will be available in March, but it’s hard to see where such an expansive TV display would fit in most homes. Micro-LEDs will have to get even smaller (again, there is no official measurement of “micro”) before the prices and the screen sizes make sense for consumers.
And now about those rollable displays. TCL in its online press conference also demonstrated flexible OLED displays; one was in the form of a phone that rolls out to extend the display (LG also teased a rollable phone). TCL’s other rollable display came in the form of a scroll about the size of a folded compact umbrella. It unrolls to a 17-inch display. Had there been an in-person CES audience, these would definitely have sparked gasps and rustles in the crowd, but they are likely a long way from appearing on store shelves.
Tekla S. Perry is a senior editor at IEEE Spectrum. Based in Palo Alto, Calif., she's been covering the people, companies, and technology that make Silicon Valley a special place for more than 30 years. An IEEE member, she holds a bachelor's degree in journalism from Michigan State University.