Fans of TV gear love to debate the merits of the two leading flat-panel technologies: Quantum Dot LED (or QLED as it’s most commonly known) and Organic LED, otherwise known as OLED. Each has its advantages, but also its weaknesses. But just over the horizon — and getting closer every day — is a new display technology called Quantum Dot OLED or QD-OLED. As the name suggests, it’s a hybrid of QLED and OLED, and if it lives up to its promises, it might just be the best display technology we’ve ever seen.
But what exactly is QD-OLED, why does it have the potential to be a picture quality game-changer, and which companies are using it to make new TV models? Let’s take a deep dive into the details of QD-OLED and find out.
What is QD-OLED?
Simply put, QD-OLED is a hybrid display technology that aims to take the already very impressive qualities of OLED TV and improve on brightness and color through the use of quantum dots.
The result, according to experts, should be a TV that exhibits the stunning levels of contrast and perfect blacks of OLED while delivering brightness levels that we’ve traditionally only seen on QLED TVs. In short, it should give us the best of both worlds.
It’s also possible that over time, QD-OLED TVs may prove less expensive to buy than similarly sized OLED TVs. We’ll discuss this in more detail later.
How does QD-OLED work?
To understand the inner workings of QD-OLED, we need to quickly explain the differences between QLED and OLED.
The LED backlight produces all of the brightness you see — and modern LED backlights can produce a lot of brightness, far more than OLED light sources. But achieving that brightness while maintaining a full-spectrum white, is difficult.
The solution: Start with a really bright blue LED light source, then use red and green quantum dots to balance the blue into a full spectrum of white. Because quantum dots can be tuned to emit specific colors and, amazingly, can do this at a nearly 100% efficiency level, QLED TVs get a much-needed improvement to their color accuracy without sacrificing any brightness or needing to use more energy.
From there, the purified white light passes through the LCD matrix (which is responsible for the images you see, and how bright or dark areas of the screen are) and, finally, through the color filter, which converts the white light into the right amounts of red, green, and blue so that we see true color images.
It’s a good system that produces bright and very colorful images. It’s also quite affordable to produce because, with the exception of the quantum dots, all of the components have been around for decades, and are now “cheap” to make.
But it has drawbacks, too. No matter how hard the LCD matrix tries, it can’t block 100% of the light from coming through in dark scenes, so you never get that perfect, inky black that you see on an OLED TV. The LCD matrix also creates problems for off-angle viewing because it has a tendency to “tunnel” light straight outward from the screen.
QLED also has to use more energy to create the brightness you see because the combination of the LCD matrix and the color filter diminishes the light the LED backlight generates. This makes QLED TVs less energy efficient than OLED TVs.
Finally, and this may only matter to decor-oriented TV buyers, all of those elements add up to a thicker overall TV panel.
OLED TV uses an OLED light source and a color filter to produce its image.
That sounds remarkably simple compared to QLED TV, and it is. Thanks to the emissive nature of the basic element of OLED TV — the OLED pixel — this one ingredient can take care of brightness and image creation, essentially fulfilling the roles of both the LED backlight and the LCD matrix in QLED TV.
Without an LCD matrix, viewing angles with OLED TV are as near-perfect as we’ve ever seen. You can sit wherever you like and still see the same levels of brightness, contrast, and color.
And as we’ve already hinted at, because OLED pixels can be shut off completely when an image calls for perfect blackness, that’s exactly what you get: No light being emitted at all.
But OLED TV isn’t perfect either. You can only derive so much brightness from an OLED pixel. It’s excellent in low-light conditions, but it simply can’t compete with QLED’s dedicated LED backlight in brighter environments. If you’ve ever looked at a QLED and OLED TV side by side in a brightly lit Costco warehouse and found the QLED TV more appealing, it’s probably due to its superior brightness.
OLED TV brightness is lower than QLED for two main reasons. First, and most importantly, each OLED pixel creates its own light. These pixels are incredibly small, so there’s a limit to how much light they can emit. The LEDs used in a QLED TV’s backlight are huge by comparison — even the new mini-LED backlights being used by TCL are still far bigger than pixel-size.
Second, no matter how much light an OLED pixel can create, some of that light will be absorbed by the color filter.
Manufacturers could choose to overcome this barrier by forcing the OLEDs to emit more light, but an OLED’s life span is inversely proportional to its brightness — the more power you push through it, the faster it will die.
OLED panels are also susceptible to something known as burn-in. If you display the same kind of content on an OLED TV for tons of consecutive hours — say a lower info banner on a news channel, or a control panel in a video game — it can cause those pixels to age at a faster rate than the pixels that are constantly displaying different images.
The residual “shadow” of that static content is called burn-in, and once it happens, it’s usually permanent.
Finally, because the large-format OLED panel market is effectively a monopoly, with just one company — LG Display — manufacturing and selling them to companies like LG, Sony, Philips, and Vizio, it will remain more expensive than QLED for some time to come.
QD-OLED: Busting the brightness barrier
So the question that faces the TV world is, how can you hold on to all of OLED’s many benefits and improve on its weaknesses?
The favored solution right now is QD-OLED.
Quantum Dot OLED significantly increases the overall brightness of OLED — and even improves its already superb color — by optimizing how much light a single OLED pixel can emit and eliminating the color filter.
Here’s how it works.
Why start with white?
At the moment, OLED TVs create their light and color starting point with white light. They do this by combining blue and yellow OLED material to create a blend that comes very close to pure white. Why do this instead of using red, green, and blue OLED material? The answer has to do with the complexities of manufacturing OLED panels at the 50-inch to 88-inch sizes of today’s TVs while keeping costs as low as possible.
To give you a sense of just how expensive a true RGB OLED panel is, Sony makes a 4K, 55-inch monitor for the broadcast and film industries that uses this technology. It costs nearly $28,000.
But when you start with white light, you need a way to separate the individual red, green, and blue portions of the spectrum. A color filter does this admirably, but color filters, as we mentioned above, reduce brightness.
LG’s technique for regaining some of the brightness lost to the color filter involves the use of a white subpixel that bypasses the color filter.
When you’re watching standard dynamic range (SDR) content, the use of that white subpixel is moderate. OLED TVs can easily get bright enough to meet the full specification for SDR without relying heavily on the brightness of the white subpixel.
“Displays of all types that use this architecture are able to achieve color accuracy at relatively lower luminance,” said Jeff Yurek, director of marketing and investor relations at Nanosys, a company that develops quantum dot technology. But HDR material is a bit trickier.
When viewing HDR content, the panels turbocharge these white subpixels to deliver HDR’s higher brightness. But there’s a limit to how hard you can drive those white subpixels. Push them too far and not only do you reduce the panel’s life, but that extra brightness can also wash out the color of the other subpixels.
Back to blue
To deal with the technical hurdles of OLED brightness, QD-OLED TVs take a page out of QLED TV’s handbook. Using the same principle that lets a QLED TV turn a blue backlight into a pure white light using red and green quantum dots, a QD-OLED panel uses just blue OLED material as the basis of each pixel.
That blue OLED pixel is then divided into three subpixels: A blue subpixel, which is the original blue OLED material, left unchanged; a red subpixel that uses red-tuned quantum dots; and a green subpixel that uses green-tuned quantum dots.
Since quantum dots are so energy-efficient, virtually no brightness is lost in those two color transformations. The result is a true RGB OLED display without the cost and complexity of a discrete RGB OLED starting point, the brightness tax of a color filter, or the need for a color-sapping white subpixel.
“What is so exciting about QD-OLED displays,” Yurek said, “is that they do not require a white subpixel to reach peak luminance. QD-OLED will be able to express the full color volume from near black all the way up to full-peak luminance without compromise.”
QD-OLED: More affordable?
It may take several years, but it’s possible that QD-OLED TVs will end up costing less than OLED TVs to make. Getting rid of the color filter is a great way to reduce materials and manufacturing complexity, which should mean a smaller outlay of cash.
And since QD-OLED will theoretically be brighter than OLED without the use of more electricity, it might be possible to create QD-OLEDs that have the same brightness as OLED while using less energy. Lower energy use brings down the cost of many of the components that have to be engineered to handle higher energy loads.
This all assumes that the investments needed to make QD-OLED manufacturing a reality will be paid off quickly, but that’s far from certain at this point.
Having your (OLED) cake and eating it, too
Blue OLED material — the currently expected light source of QD-OLED displays — is a notoriously tricky substance to work with.
Much like other OLED materials, there’s a three-way trade-off between life span, brightness, and efficiency. Generally speaking, any time you prioritize one of these attributes, the other two suffer. Drive an OLED pixel hard enough to produce the brightness you want and you not only diminish its life expectancy but also its efficiency.
But QD-OLED displays may prove to be the exception to this rule. By using three layers of blue OLED material per pixel, each layer can share the brightness burden.
“The amount of power needed from the blue OLED pixel in the QD-OLED to produce a given amount of front-of-screen brightness will be less,” said Jason Hartlove, CEO and president of Nanosys.
Who’s going to make QD-OLED TVs?
At the moment, we know that Samsung is heavily investing in QD-OLED manufacturing. But that doesn’t mean the company will be the first to sell QD-OLED TVs.
In fact, there appears to be some infighting between Samsung Display, the division that has made the QD-OLED investments, and Samsung Visual, the division that markets the company’s TVs.
Because of Samsung Visual’s reluctance to embrace QD-OLED — partially because it has spent a lot of time and money casting a negative light on LG’s OLED technology in contrast to Samsung’s QLED tech — we might get our first real glimpse of QD-OLED from TCL.
TCL is apparently in talks with Samsung Display and Japan OLED (JOLED), a joint venture between Panasonic, Sony, and Japan Display to acquire QD-OLED panels, according to a report from DisplayDaily, which further suggests TCL could show the first of these TVs publicly at IFA 2021. We know that TCL has been working on OLED display technology — the company recently demonstrated its own sideways-rolling OLED at DTC 2020 in Shenzen, China — but it has yet to sell a consumer-targeted OLED TV.
When will QD-OLED TVs be available to buy?
If the TCL rumors are correct and the company does show a QD-OLED model in September 2021, the logical timing would be some time in 2022, possibly as late as the fourth quarter.
How much will they cost?
It’s hard to imagine that the first QD-OLED TVs will be the same price or cheaper than a smae-sized OLED TV, at least at first. However, in time, their simplicity of design and lower power consumption should yield TVs that are less expensive than those that are built using traditional OLED technology.
Is QD-OLED the last word in TV technology?
Nothing halts the progress of technology, and the companies that manufacture quantum dots have their sights set firmly on the eventual domination of the TV landscape.
Remember when we said that quantum dots use light energy at almost 100% efficiency to produce their own light? Well, it turns out that quantum dots aren’t picky about their diet. They can also be energized using electricity for what’s known as quantum dot electroluminescence, or QDEL.
Eventually, this means we’ll be able to ditch OLED and LED light sources, and create ridiculously thin, flexible, colorful, bright, and energy-efficient displays that never diminish in brightness or color accuracy over time.
QDEL sounds like the holy grail of TV tech, doesn’t it? But we’re not quite there yet. At the moment, blue quantum dots possess the necessary attributes to act as electroluminescent subpixels, however, red and green quantum dots still need work.
It’s also possible we’ll see MicroLED emerge as a contestant for the home display market. But current models are huge, expensive, and pack lower resolutions per inch than either QLED, OLED, QD-OLED, or QDEL. MicroLED may never be practical or affordable at sizes of 50 to 100 inches.