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QLED vs. OLED: Samsung and LG TV technologies explained

Samsung's QLED and LG's OLED televisions may sound similar, but the difference is actually a really big deal.

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Samsung uses QLED for its best TVs, but don't confuse it with LG's OLED.

Sarah Tew/CNET

In 2021, the high-end TV landscape is just as confusing to new buyers as ever. There's a bunch of new televisions to consider, a raft of technical-sounding features -- 8KHDRUltra HD 4K120Hz and HDMI 2.1 -- and a stable of familiar brand names competing for your dollar. Two of the biggest, Samsung and LG, use very similar terms to describe their best TVs, but Samsung's QLED and LG's OLED are as different as day and night.

For the last few years, Samsung, the most popular TV maker in the world, has been branding its TVs "QLED." Its 2021 QLED lineup is massive, with Neo QLED models in 4K and 8K resolution, The Frame art TVSerif and the Sero rotating TV all bearing the ubiquitous Q. Meanwhile, LG's 2021 OLED TVs include six series, from the relatively affordable A1 to the crazy-expensive 8K Z1 to, yes, a model that rolls up like a poster.

The OLED vs. QLED battle goes beyond Samsung and LG. TCL also brands its best TVs "QLED," including the 6-Series and 8-Series. And other brands beyond LG also sell OLED TVs, namely Sony and Vizio.

So which one is better? In our side-by-side comparison reviews of picture quality, OLED beats QLED every time. I haven't tested the latest crop of 2021 QLED and OLED models yet, but based on what we've seen in the past, I expect OLED to continue to produce superior image quality to QLED. Here's why.

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A QLED TV is just an LCD TV with quantum dots

Let's start with a quick summary of the two technologies.

  • OLED stands for "organic light emitting diode."
  • QLED (according to Samsung) stands for "quantum dot LED TV."
  • OLED is a fundamentally different technology from LCD, the major type of TV today.
  • QLED is a variation of LED LCD, adding a quantum dot film to the LCD "sandwich."
  • OLED is "emissive," meaning the pixels emit their own light.
  • QLED, like LCD, is, in its current form, "transmissive" and relies on an LED backlight.

The main takeaway is that QLED is closer to regular old LCD than it is to OLED, which I (and most other experts) consider a distinctly different class of television, much like plasma was before it.

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Quantum dots are microscopic molecules that, when hit by light, emit their own, differently colored light. In QLED TVs, the dots are contained in a film, and the light that hits them is provided by an LED backlight. That light then travels though a few other layers inside the TV, including a liquid crystal (LCD) layer, to create the picture. The light from the LED source is transmitted through the layers to the screen's surface, which is why we say it's "transmissive."

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A look at the "sandwich" of layers in an LCD TV, where an LED backlight shines through a quantum dot layer (among others) and on to the LCD panel itself.

Josh Miller/CNET

Samsung has been using quantum dots to augment its LCD TVs since 2015 and debuted the QLED TV branding in 2017. Samsung says those quantum dots have evolved over time -- that color and light output have improved, for example. In my experience however, improvements caused by better quantum dots are much less evident than those caused by other image quality factors (see below).

Other TV makers also use quantum dots in LCD TVs, including Vizio and Hisense, but don't call them QLED TVs.

An OLED TV is not an LCD TV at all

LCD is the dominant technology in flat-panel TVs and has been for a long time. It's cheaper than OLED, especially in larger sizes, and numerous panel makers worldwide, including LG itself, can manufacture it.

LG OLEDC8P series

OLED TVs don't need LED backlights so, in addition to image quality benefits, they can get amazingly thin.

Sarah Tew/CNET

OLED is different because it doesn't use an LED backlight to produce light. Instead, light is produced by millions of individual OLED subpixels. The pixels themselves -- tiny dots that compose the image -- emit light, which is why it's called an "emissive" display technology. That difference leads to all kinds of picture quality effects, some of which favor LCD (and QLED), but most of which benefit OLED.

Aside from the US brands mentioned above, Panasonic, Philips, Grundig and others sell OLED TVs in Europe. All use panels manufactured by LG Display, however.

QLED vs. OLED: image quality compared

Based on my reviews, here are some general comparisons I've made between the two.

QLED TV picture quality varies more than OLED. Samsung and TCL each have multiple QLED series and the most expensive perform a lot better than the cheaper ones. That's mainly because the biggest improvements in the picture quality of QLED sets don't have much to do with quantum dots. Instead they're the result of mini-LED backlightsbetter full-array local dimming, bright highlights and better viewing angles, which help them outperform QLED (and non-QLED) TVs that lack those extras.

Meanwhile, every OLED TV I've reviewed has very similar image quality -- all have earned a 10/10 in picture quality in my tests. There's some variation among different OLED TVs, but they're not nearly as significant as the differences between various QLED TV series. In 2021, LG and Sony will sell the first OLED TVs that might perform significantly better, thanks to higher brightness. We'll see.

OLED has better contrast and black level. One of the most important image quality factors is black level, and their emissive nature means OLED TVs can turn unused pixels off completely, for literally infinite contrast. QLED/LCD TVs, even the best ones with the most effective full-array local dimming, let some light through, leading to more washed-out, grayer black levels and blooming around bright sections.

QLED is brighter. The brightest QLED and LCD TVs can get brighter than any OLED model, which is a particular advantage in bright rooms and with HDR content. In my tests, however, OLED TVs can still get plenty bright for most rooms, and their superior contrast still allows them to deliver a better overall HDR image than any QLED/LCD TV I've tested.

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Sarah Tew/CNET

OLED has better uniformity and viewing angles. With LCD-based displays, different areas of the screen can appear brighter than others all the time, and backlight structure can also be seen in some content. Even the best LCDs also fade, lose contrast and become discolored when seen from seats other than the sweet spot directly in front of the screen. OLED TVs have almost perfectly uniform screens and maintain fidelity from all but the most extreme angles.

Resolution, color, video processing and other image quality factors are basically the same. Most QLED and OLED have the same resolution and 4K, and both can achieve 8K resolution too. Neither technology has major inherent advantage in color or video processing areas. Check out OLED vs. LCD for more details.

QLED can get bigger and smaller (and cheaper)

There are only five sizes of OLED TV on the market today: 48-, 55-, 65-, 77- and 88-inch, with an 83-inch version on sale later in 2021. Meanwhile, QLED TVs come in 32, 43-, 49-, 55-, 65-, 75-, 82-, 85- and, yes, 98-inch sizes. Of course, non-QLED LCD TVs can get even smaller.

LG Signature OLED 8K

LG's 88-inch 8K OLED TV costs $30,000.

Sarah Tew/CNET

One big advantage, so to speak, that QLED and LCD have over OLED is the cost of mainstream sizes over 65 inches. Large televisions are the fastest-growing segment of the market and show no signs of slowing down. LG's 77-inch OLED costs around $3,300, significantly more than most 75-inch QLED TVs, and in larger sizes the difference is even more drastic.

What about OLED burn-in?

Burn-in happens when a persistent part of the image onscreen -- navigation buttons on a phone or a channel logo, news ticker or a scoreboard on a TV, for example -- remains as a ghostly background no matter what else appears onscreen. All OLED screens can burn-in, and from everything I know, they're more susceptible than LCD displays, including QLED.

All things considered, however, burn-in shouldn't be a problem for most people. From all of the evidence we've seen, burn-in is typically caused by leaving a single, static image element, like a channel logo, onscreen for a very long time, repeatedly. That's an issue if you keep Fox News, ESPN or MSNBC onscreen for multiple hours every day and don't watch enough other programming, for example. But as long as you vary what's displayed, chances are you'll never experience burn-in.

Check out OLED screen burn-in: What you need to know for more.

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Electroluminescent quantum dot prototypes, which could pave the way for direct-view quantum dot TVs.

QDVision

Future outlook for OLED vs. QLED TVs

Until I pit the best 2021 QLED TVs against the best OLED TVs I won't know for sure which one wins this year, but as I mentioned above, I'd bet on OLED. 

What about the future? Samsung is actually working on an OLED TV of its own (again), investing $11.1 billion in new facilities to create "QD display" tech that's basically OLED with a different name -- and quantum dots, natch. Rumors pin 2022 as the earliest customers could buy one.

Separately, and further down the road, Samsung is researching direct-view quantum dot, which dispenses with the liquid crystal layers and uses quantum dots themselves as the light source. Emissive QLED TVs have the potential to match the absolute black levels and "infinite" contrast ratio of OLED, with better power efficiency, better color and more. That's pretty exciting, but it'll be a few years before we see emissive QLED TVs available for sale. Hopefully, by then they'll think up a new acronym (EQLEDs?).

And then there's MicroLED. It's another emissive technology, once again spearheaded by Samsung that on sale now to the very rich. As you might guess from the name, it uses millions of teeny-tiny LEDs as pixels. 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. It's also friggin' huge. It doesn't involve quantum dots, at least not yet, but who knows what might happen when it comes to market. QDMLED, anyone?

For now, however, OLED rules the picture quality roost over QLED.