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. 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. It’s possible we 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.
Winner: OLED
QLED vs. OLED TV: What’s the difference, and why does it matter? [Digital Trends]