The world of flatscreen displays is dense with terminology that can seem deliberately created to mislead. From endless acronyms that look and sound deceptively similar but have totally different meanings or old technologies that get rebranded with new, more jargony monikers.
Developed by Samsung, QD-OLED is one of the newest and most exciting kids on the flat panel block. For once, its name represents exactly what it is: a combination of the Quantum Dot (QD) displays, endorsed by market leader Samsung as well as the likes of Hisense, Vizio and Roku, and OLED technology, of which Samsung's arch-rival LG is the dominant player, as the sole supplier of large OLED panels to other manufacturers.
The two screen types have different strengths and weaknesses, and combining them could potentially yield results greater than the sum of the parts achieving that holy trinity of TV manufacturing: vivid colours, high peak brightness without light bleed, and dark, saturated blacks.
But how will it work? When will it be available? And why has Samsung, which has been an avid anti-OLED campaigner until now, suddenly done a U-turn? We'll try to answer all these questions below but first, since QD-OLED is a hybrid, let’s recap the individual components before tackling the whole.
OLED vs QLED: which is the best TV technology?
How does OLED work?
OLED (Organic Light-Emitting Diode) is a type of display that uses an organic carbon-based film through which two conductors pass a current, causing it to emit light. To produce an image, an OLED TV combines blue and yellow light from OLED sources to create almost white light. This is then passed through a colour filter made up of red, blue and green subpixels.
Unlike traditional LCD TVs, which rely on a separate backlight that’s then passed through a layer of pixels, each individual pixel in an OLED can take care of both brightness and image creation. Because each pixel is its own light source and can be completely blacked out if need be, this means that a bright pixel can appear next to one that’s black with neither impacting the other, creating the exceptional overall contrast for which OLEDs are rightly renowned.
And that's not the only benefit. Because the image doesn't need to pass through an LCD matrix, viewing angles are wide, while the overall build of an OLED TV is thin and light because of its simple structure.
The downside to OLED TVs is that they struggle to reach the same peak brightness as even an average backlit model, as each pixel is limited by its size in the amount of light it can produce and by energy absorption from the colour filters. To address this, LG started using a WRGB pixel structure - adding a white subpixel to try and increase brightness levels. Unfortunately, this has drawbacks and can wash out the colour of the other subpixels. Also, as the organic material in OLEDs is not permanently stable, its lifespan decreases at an inverse rate to the amount of brightness it is made to produce. So pushing the white sub-pixel could shorten your TV's life expectancy.
A slightly more controversial issue facing OLEDs is that the organic nature of the panel means it's potentially susceptible to image retention and even burn-in. This is not the consistent, widespread problem that some (including Samsung) portray it to be, though, and we've never experienced it with any of the OLEDs that we've tested or that have been used at home by our reviewers. But it's still understandably a concern for some buyers, and companies take it seriously enough to build in features to reduce the risk of it happening.
As we said above, LG is the only manufacturer of TV OLED panels. It uses these for its own sets, of course, but it also sells panels to other manufacturers such as Sony, Panasonic and Philips. After a quick foray into the world of OLEDs in 2013, Samsung has since focused its attention on developing rival technologies such as QLED. The company has been known to deliberately stoke consumer doubts over the reliability of OLEDs, even going so far as to create a TV burn-in checker tool and encouraging affected customers to trade in their OLED for a QLED.
How does QLED work?
QLED stands for Quantum dot Light Emitting Diode and was developed to try and replicate the very best picture quality features of OLED (super-deep blacks, amazing contrast, wide viewing angles) along with far superior brightness and colours. A QLED uses an LED backlight, a layer of quantum dots, an LCD matrix, and a colour filter to create an image.
The quantum dots in QLEDs are tiny semiconductor particles only a few nanometers in size. The dots convert white light into coloured light without loss of energy. The resulting colour depends on the size of the quantum dot itself – larger ones give off light at the red end of the spectrum, smaller ones at the blue end.
In the future, engineers hope to make these semi-conductors self-emissive, like OLED and MicroLED technology but, right now, they rely on being lit from an external source.
The advantage of quantum dots is that they offer significantly improved colours over both traditional LCD and, arguably, even over OLED. At the same time, the backlight and energy efficiency of the dots creates brightness levels that OLED can’t get close to. However, it still can't achieve the deep blacks of an OLED as light can bleed from white areas to bordering dark pixels.
Samsung has sought to increase the contrast of its models by shrinking its backlights and switching from standard LEDs to Mini LED backlights for its premium 'Neo QLED' TVs. As the name suggests, these backlights use much smaller LEDs packed in far higher quantities for more independent dimming zones. These LEDs are so tiny that they resemble grains of sand, but for the ultimate in accurate dimming, it seems you can't beat a pixel-sized backlight.
How does QD-OLED technology work?
In QD-OLEDs, a stack of blue OLED material is used to illuminate pixels that contain red and green quantum dots.
Each OLED pixel is divided into three subpixels: a blue subpixel consisting of the original blue OLED material, a red subpixel with red-tuned quantum dots, and a green subpixel generated by a green-tuned quantum dot. These can then be combined to create true white light.
Unlike when using filters, the colour transformations performed by the quantum dots lose virtually no light energy. Using this method of OLED illumination, the new QD-OLEDs are said to appear brighter than current OLED TVs while still maintaining the ability to be fully dimmed.
So why don't OLEDs just use red, blue and green emissive material and cut out the brightness sapping filters? This is mainly due to the practicality of manufacturing true RGB panels at the sizes required of modern TVs. In fact, Samsung's only OLED, the S9C, tried to do this but was deemed commercially unviable before being quickly retired.
If successful, QD-OLEDs could potentially offer the contrast of OLED and the brightness and vibrancy of QLED.
Samsung says that its QD-OLEDs with 4K resolution will have about 8.3 million (3840x2160) light sources that can be controlled separately, enabling a high contrast ratio of 1,000,000:1 and offering enhanced image detail and better HDR performence.
In terms of colour, the company claims that QD-OLED will offer one of the broadest colour expressions among its current crop of displays. Based on the BT.2020 specifications, QD-OLED will express a colour volume above 80% as well as apparently delivering 0.0005 nits blacks and 1000 nits peak white.
What other benefits will QD-OLED offer?
By omitting an LCD layer, display response times, viewing angles, and screen reflection should be improved compared to traditional LCD displays. Samsung also claims that the screen will offer a 40-50% reduction in "harmful blue light" as the blue OLED material will primarily produce light with a wavelength longer than 455nm.
Have Samsung fixed the problems with OLED?
After years of deriding OLEDs, how will Samsung respond to questions of the reliability of the technology it is now adopting?
Reports indicate that by using a stack of three layers of OLED material, Samsung hopes to distribute the burden of brightness production and prolong the QD-OLEDs life expectancy far beyond that of a normal OLED. But there are certainly other factors to consider.
As to how Samsung will approach these thorny issues, we can only speculate. The company may point to its use of OLED displays in phones as proof it has long embraced the technology, or it may just maintain it has now solved all of the problems with LG's large OLED panels with this new hybrid, offering all of the pros of QLED and OLED and none of the cons.
But for now, it seems that Samsung will just avoid using the term OLED at all. A recent post about the new screen technology on Samsung's website refers to the organic material as the " blue self-luminescence layer" and in side by side comparisons only mentions traditional LCD displays. Moreover, the company appears to be eschewing the QD-OLED label entirely, favouring the slightly clunky term 'QD Display TV' instead. We'll take an acronym over that any day.
When will the first QD-OLED TVs be launched?
There’s nothing confirmed just yet, but plenty of rumours suggest it won’t be too long before we can get our hands on a QD-OLED.
From reports that panel manufacturers Samsung Display have struck a deal to supply Samsung Electronics with QD-OLED panels, to rumours that the hotly anticipated sets will debut at next January’s Consumer Electronics Show, all indications point to a release in the first half of 2022.
Meanwhile, TCL is developing its own take on QD-OLED called H-QLED, but there's currently little extra information about it other than that it will be ink-jet printed.
How much will QD-OLEDs cost?
Insiders have suggested that the QD-OLED TVs will sit between Samsung’s six-figure super-premium MicroLED TVs and its flagship QLED lines, meaning they are likely to be more expensive than LG's OLED TVs.
Reports hint that QD-OLEDs will initially launch in 55-inch and 65-inch sizes, with larger 70-inch models appearing at a later date, with no word yet on if they are set to be 4K or 8K.
Samsung Displays is thought to have invested $11.7 billion in QD technologies since 2019. As it plans to end LCD production by 2022, it will certainly be looking for a considerable return on its new venture. Theoretically, as QD-OLEDs are simpler in design and use fewer materials, manufacturing costs could eventually drop to below that of OLEDs, potentially making them cheaper to buy in the long run.
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