If you’re shopping for a 4K TV at the higher end of the market, you’ve likely stumbled upon two similar-sounding terms: QLED and OLED.
Though they share three of the same letters, make no mistake: These are very different technologies, each with its own strengths and weaknesses, and both driving some of the best TVs on the market. We’ll quickly cover what each term means, and then dig into how TVs that are based on these technologies differ so that you can make an informed choice when it’s time to buy.
What is QLED?
QLED stands for Quantum Light-Emitting Diode. In non-geek-speak, that means a QLED TV is just like a regular LED TV, except it uses “quantum dots” embedded into its LCD panel — tiny nanoparticles that dramatically improve the color and brightness when compared to its non-quantum LED counterparts. The technology was initially brought into consumer TVs by Samsung, but thanks to a licensing partnership, other manufacturers are now using it too.
How do quantum dots work? Check out our deep-dive into the technology for all of the details.
The most important thing to know about QLED TVs — quantum dots notwithstanding — is the way they produce the light that hits your eyes. That light comes from a series of LEDs that sit behind an LCD panel — it’s these LEDs that give LED (and QLED) TV its name. Some LED TVs have a handful of these LED backlights, while some have thousands. We’ll get into why more is better later on. Before the light emitted by these LEDs reaches your eyes, it passes through an LCD matrix — essentially millions of tiny shutters that open and close too quickly to see. These shutters — along with quantum dots in a QLED TV — create the picture you see by letting just the right amount of light get through, and filtering it to create the colors. It’s a clever system, but it relies on a combination of dimming the LED backlights and using the shutters to block the remaining light in order to produce true blacks, something we’ll explore below.
You’ll find QLED TVs made by Samsung, Hisense, Vizio, and soon, TCL.
What is OLED?
OLED stands for Organic Light-Emitting Diode. Somewhat surprisingly, the “Light Emitting-Diode” part of that name has nothing to do with an LED backlight as it does with QLED and LED TVs. Instead, it refers to the fact that every single pixel in an OLED TV is also a teeny, tiny LED light — but one that is incredibly thin and can produce both light and color in a single element. In other words, OLED TVs don’t need a backlight because each pixel produces its own light.
There are several advantages to this design, but most would agree that when used in a TV, the biggest advantage is the superb black level that can be achieved. Unlike a QLED or LED TV that must dim its backlight and block what remains for dark scenes, an OLED TV simply turns off the pixel. When the pixel is off, it emits no light and no color, making it as dark as when the TV itself is turned off. It’s also a lot easier to make a flexible OLED screen, which is why OLED pioneer LG has already done it.
Only one company currently makes OLED TV panels: LG. LG sells its own OLED TVs — some of which we still consider to be the very best TVs you can buy — but it also sells OLED panels to companies like Sony, which is why you’ll see Sony OLED TVs. Though the panels themselves are essentially identical, the image processing that Sony, LG, and others do is proprietary, which is why there can still be significant differences in picture quality from one OLED TV to another.
QLED vs. OLED
Now that you know what all those letters stand for, and what they mean in terms of display technology, let’s compare QLED to OLED in the categories that matter most when buying a TV: Brightness, contrast, viewing angles and other notable performance considerations, like response time and lifespan — all important factors when you’re shelling out up to $6,000 for a top-of-the-line TV.
Black levels and contrast
Contrast is the difference between the darkest part of an image and the brightest part. If a TV can deliver a truly black dark portion, it doesn’t have to make the bright parts quite as bright to achieve good levels of contrast. That’s why, when it comes to black levels, OLED reigns as the undisputed champion — because of its ability to go completely black when it needs to.
QLED TVs (ahem) by contrast, are forced to dim their LED backlights and block the remaining light, something that is very hard to do perfectly. It can trigger something called “light bleed,” as the light spills onto what’s supposed to be a black section of the screen.
But is it noticeable? Definitely. If you’re watching an intense action movie and two characters are running through a parking lot at night, for example, you may notice a slight glow on parts of the scene that are supposed to be pitch black, or in the letterbox bars at the top and bottom of the screen while watching a movie on a DVD.
In fact, getting LED-backlit TVs to go really dark is so difficult, TV makers have been forced to increase the number of LEDs used so that they have greater control over which parts of the image get dark. We may have already reached the best black levels possible with QLED TV. Samsung is almost ready to start selling microLED TVs that use individual LEDs for each pixel, which should theoretically deliver black levels on par with OLED.
For now, however, OLED comes out on top; if a pixel isn’t getting electricity, it doesn’t produce any light and therefore stays totally black.
QLED TVs have a considerable advantage when it comes to brightness. Because they use separate backlights (instead of relying on each pixel to create its own light) these LED backlights can be made incredibly, achingly bright. Add a quantum dot’s ability to maximize that light by producing brighter hues in the color spectrum without losing saturation and you’ve got a display that is more than bright enough to be seen clearly in even most brightly lit rooms.
OLED panels can’t compete on a pure brightness basis. Their light-emitting individual pixels simply can’t produce the same amount of light. In a darkened room, this isn’t a problem, in fact it might be preferable — remember a QLED TV needs to get brighter to offer the same relative contrast between its dark and light areas — but in well lit environments, or where lots of daylight streams in through windows, QLED TVs are more visible — especially if you’re playing HDR content under these conditions.
OLED once blew all the competition out of the water in this section, but the use of quantum dots in QLED TVs have allowed it to inch forward in terms of color accuracy, color brightness, and color volume — according to Samsung, which claims that a wider range of better-saturated colors at extreme brightness levels are an advantage.
While there’s no denying the fact that QLEDs deliver fantastic colors, we have yet to witness better-saturated colors at high brightness levels delivering real advantage in normal viewing situations — so we’re going to declare it a draw for now, since color is subjective. We’ll need to see some tangible evidence to declare QLED a winner.
Response time, input lag, and refresh rate
Response time refers to the time it takes for a pixel to switch from one state to another. The faster the response time, the crisper the image, especially during fast-action scenes. Though there is likely a speed of response time beyond which the human eye is incapable of telling a difference, we know from standardized measurements that OLED TVs are way faster — orders of magnitude faster than QLED TVs.
Typical QLED response times vary between 2 and 8 milliseconds, which sounds pretty good until you realize that OLED’s response time is about 0.1 millisecond. Yup, it’s no contest.
Input lag, on the other hand, refers to the delay between taking an action (say pressing a button on a game controller) and seeing the result of that action on-screen. As such, input lag is really only a concern for gamers — it doesn’t have a noticeable effect on passive viewing of content at all. Moreover, the amount of input lag you experience has little to do with one display technology over another, but more to do with how much image processing is happening on your TV behind the scenes. Both QLED and OLED TVs can achieve very low levels of input lag if you turn off all extra video processing or simply use the TV’s Game Mode, which effectively does the same thing.
Refresh rate is another category that will inherently matter more to gamers than casual viewers. It refers to the number of times per second the TV updates what it’s showing on-screen. Under normal circumstances, a TV will use a refresh rate of 60Hz or sometimes doubles that — 120Hz. Some games running on some consoles or PCs actually use what’s known as VRR or Variable Refresh Rate. If your TV doesn’t support VRR, it can cause some unwanted side-effects like screen-tearing when used with VRR games. You can find VRR models in both OLED and QLED TVs, so it’s really about making sure your choice of TV has it if you need it.
Given OLED’s unbeatable superiority in response time, it owns this category.
With QLED screens, the best viewing angle is dead center, and the picture quality diminishes in both color and contrast the further you move side to side, or up and down. While the severity differs between models, it’s always noticeable — despite TV makers’ best efforts to eliminate the issue.
OLED screens, for comparison, can be viewed with no luminance degradation at drastic viewing angles — up to 84 degrees. Some QLED TVs have improved in terms of viewing angle, with anti-reflective layers helping, but OLED maintains a clear advantage. So if you like to arrange family screenings for your favorite movies, and want to make sure there isn’t a bad seat in the house, an OLED TV is best for you.
OLEDs have come a long way. When the tech was still nascent, OLED screens maxed out at 55 inches. Today, an 88-inch OLED is available. With that said, there are fewer limitations on QLED display sizes, with some TVs growing as large as 100 inches and beyond — with Samsung’s largest consumer model measuring in at 98 inches.
LG says you would have to watch its OLED TVs five hours per day for 54 years before they fell to 50% brightness. Whether that’s true remains to be seen, as OLED TVs have only been out in the wild since 2013. QLED is even newer, but its source of backlighting — the LED — has a long and proven track record. For that reason — and that reason only — we’ll award this category to QLED.
Winner (for now): QLED
We include this section begrudgingly.
Despite persistent concerns, the reality is that the effect will not be an issue for most folks — especially for those with a QLED TV since QLED isn’t susceptible to burn-in. OLED, on the other hand, is, but you would have to be extremely unlucky for it to happen to your TV, even if you left a static image on it all day and night — repeatedly.
But before we go any further, let’s throw some context into the mix.
The effect we’ve come to know as “burn-in” stems from the days of the boxy CRT TV when the prolonged display of a static image would cause that image to appear to “burn” into the screen. That occurred when the phosphors coating the back of the screen glowed for extended periods, causing them to wear out.
QLED TVs aren’t susceptible to burn-in.
That same issue can occur with QLED TVs because the compounds that light up degrade over time. If you burn a pixel long and hard enough, you will cause it to dim prematurely and ahead of the rest of the pixels, creating a dark impression — but you would have to essentially abuse the TV to achieve this result.
Even the “bug” ( or logo graphic) that certain channels use disappears often enough, moves a few pixels every few minutes or is made clear to avoid causing burn-in issues. You’d have to watch ESPN all day every day (for many days on end) at the brightest possible setting to cause a problem, and even then it still isn’t very likely.
That said, the potential is there, and it should be noted. Gamers in particular who leave their TV on while a static image remains on-screen, or who play for 10 hours a day for many weeks at a time could potentially cause some “burn-in” on an OLED TV. But, since QLED TVs aren’t susceptible to burn-in, they win this fight by a technicality.
OLED panels are extremely thin and require no backlight. As such, OLED TV’s tend to be lighter in weight than QLED TVs and thinner. They also require less power, making them more efficient.
Once upon a time, this category would be handily won by QLED TVs, but OLED TVs have come down in cost, and since we’re talking all-premium here, comparable QLED TVs cost about the same (or more, depending on the size). That said, the least expensive QLED TV is slightly cheaper than the least expensive OLED of the same size, but not by much.
Both of these technologies are impressive in their own ways, but we’re here to pick a winner, and for the moment, it’s OLED. With better performance in the categories that most people will notice while watching TV shows and movies, it’s the best picture quality you can buy.
QLED comes out on top on paper, delivering a higher brightness, longer lifespan, and larger screen sizes. OLED, on the other hand, has a better viewing angle, deeper black levels, and uses less power. Both are fantastic, though, so choosing between them is subjective — QLED is the better all-rounder, but OLED excels in the dark.
The fact is, you can’t go wrong with either. That is, of course, until the next generation of display technology comes along. Samsung has said it is working on embedding its quantum dot technology into OLED panels, which might create a TV with the best of both worlds, but since that’s likely a few years away still, we’ll have to wait and see.
- OLED vs. LED: Which kind of TV display is better?
- Samsung’s quantum OLED plans could mean better, cheaper OLED TVs for all
- LED vs. LCD TVs explained: What’s the difference?
- Need a 4K TV? Don’t miss your chance to bag one of Vizio’s finest
- TCL announces mini-LED and 8K along with its 2019 TV lineup