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All about QD-OLED: how does it work and what are the pros and cons?

This article will tell you All about QD-OLED. For instance, How does it work? Pros and cons? And what should that cost? and much more.

At CES 2022, the numerous rumors of 2021 were confirmed, Samsung Display makes a new screen technology available that combines quantum dots and OLED. In this background article we tell you everything you need to know about it. 

All about QD-OLED- Why a new technology?

Both OLED if quantum dots have been on the market for almost 10 years (we reviewed the first models in 2013). OLED TVs deliver perfect blacks, a wide viewing angle and excellent colours, but are somewhat limited at maximum brightness and carry a risk of burn-in. Quantum dots deliver greater color volume and brightness, but in the current implementation, these TVs essentially remain LCD TV photos with more limited contrast and viewing angle. In short, our TVs may give fantastic images, but that doesn’t mean it can’t get even better.

What does QD-OLED promise to bring us? A higher peak brightness but still the same contrast performance as OLED. An even wider color palette, with richer tones in the very brightest colors, and better color reproduction in dark scenes. An excellent viewing angle, without color shifts or less bright images. And finally, a very fast response time so that double or blurry guesses are reduced to a minimum.

The new QD-OLED screens are made today exclusively by Samsung Display, although we know that too TCL researches the technology under the name H-QLED.

How does QD OLED work?

The operation of a QD-OLED TV looks relatively simple. A blue OLED layer serves as the light source. Just like with the OLED TVs we know today, that OLED layer is applied over the entire surface of the screen, and each pixel can be controlled individually. For the red and green sub-pixels, the blue light is converted to red and green using quantum dots. For the blue pixel, the light is allowed to pass through.

Source: displaysupplychain.com

The main difference with both OL ED TVs and LCD TVs is that the sub pixels do not create color by filtering out light but by converting it to the correct color. That’s the unique feature of quantum dots. That layer is therefore no longer a color filter, we are rather talking about a color conversion layer (QDCC, or Quantum Dot Color Converter). It is precisely this difference that forms the basis of a number of important advantages.

The advantages of QD-OLED

  • Excellent contrast: QD-OLED has this in common with OLED. Each pixel generates its own light and is almost perfectly black when it is turned off. You can therefore expect perfect black and very high contrast within every image, without ‘blooming’ or zone boundaries.
  • An even wider color range. The unique combination of OLED and quantum dots without a color filter makes very rich and intense basic colors (red, green and blue) possible. This allows the TV to receive a very large color range to deliver. Samsung claims 90.3% Rec.2020, a coverage that far exceeds that of existing OLEDs (70% Rec.2020). For the P3 color range, the screen would even reach 99.8% (current OLEDs reach around 95%).

Red and green quantum dots under blue light (source: cnet.com)

  • a bigger color volume. Or more concretely: more color in clear parts. Current OLED TVs use a white sub-pixel to give the brightness a boost, but in the very brightest colors that dilutes the color reproduction somewhat, those shades are less intense. Because QD-OLED screens use a true RGB sub-pixel structure, and start with a very large color gamut, they can display those very bright colors much richer.

From left to right LG G1 OLED, Samsung QD-Display, LG QNED90 mini LED TV (source: uk.pcmag.com)

But the QD-OLED screen also seems to be able to bring out more color nuances in dark tones.

  • More peak brightness. Peak brightness is the feature where OLED has to give up the most ground over LCD TVs. According to Samsung, the new QD-OLEDs will perform better than OLEDs, but also not at the level of the best LCD TVs. These are the numbers Samsung claims: 200 nits on a completely white screen, 1000 nits on a 10% window and 1500 nits on a 3% window. Compare that to the most common OLED results: 150-170 on a full white screen, 700-900 on a 10% window and 800-1000 on a 2% window. The gain here is therefore rather modest, but it is there. However, top LCD TVs remain the champion here (2,000 nits on 10% window and 600-800 on an all-white screen).
  • A very wide viewing angle, where the image does not become dimmer or shows color shifts, even from a fairly extreme angle. The reason? QD-OLED is a top-emission technology (the light is generated at the top of the stack, read on the side closest to the viewer) and does not have to be layered before reaching the viewer. For example, there is no color filter as with OLED. In addition, the quantum dots behave like a Lambertian light source, meaning that the light source appears equally bright regardless of the direction from which you look.
  • For the same reason as for the viewing angle, top-emission technology also suffers less from reflections.
  • A very fast pixel response time. Like OLED TVs, QD-OLED will have a grey-to-grey (GtG) response time of 0.1ms. In action scenes, fast-moving objects therefore have very little trouble with blurry or double edges. That is an important advantage for sports and especially games. In addition, the screens can deliver refresh rates from 144Hz to even 175Hz. This is especially important for PC gamers, but it guarantees a very smooth and razor-sharp gaming experience.

  • Possibly more energy efficient. We have no confirmation about this yet, but since no light is filtered and the quantum dots are very efficient in the color conversion, these screens might consume less.
  • Just like OLED, the new screen technology will also enable particularly thin screens.

Who will launch QD-OLED products?

Although the announced technology comes from the labs of Samsung Display, there are no announcements from Samsung Electronics for the time being, neither for a TV nor for a monitor. That’s somewhat surprising. The reason for this is speculation, although the limited production capacity may be one reason.

Samsung calls the technology ‘QD Display’, there is no mention of the word OLED. This is probably a result of the longstanding rivalry between Samsung QLED TVs and LG OLED TVs. But that doesn’t mean Samsung Electronics isn’t done with a TV. There is indeed, but may not be introduced until later in the year.

The first TV to be effectively announced is the Sony XR65A95K. It will be available in 55 and 65 inches, unfortunately no price is known for the time being. Sony also opted for a confusing name. The XR65A95J falls under the umbrella of the OLED models. You can recognize the QD-OLED technology by the name XR Triluminos Max, the traditional OLEDs use XR Triluminos Pro.

In addition to the 55 and 65 inch 4K panel, Samsung also makes a 34 inch 3440×1440 panel for monitors. You will find that panel in the Dell/Alienware AW3423DW. The monitor has a 175Hz refresh rate. Remarkably, this monitor comes with a 3-year warranty that also covers OLED burn-in. However, the price is not yet known here either.

Conclusion

It seems very likely that QD-OLED has everything it takes to give the image quality an extra boost. In any case, the first reports confirm that the new technology combines the advantages of quantum dots and OLED. We are anxiously waiting for the first device to arrive. A full QD-OLED line-up, which will probably take a few more years, just as was also the case for OLED.

 

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