Samsung Display Release Details of Quantum Dot Display Technology

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Images courtesy of Samsung Display throughout

Back in April 2020 we had the news that Samsung Display (the panel manufacturer as opposed to the screen manufacturer) were ceasing production of LCD panels, and investing heavily in OLED and Quantum Dot (QD) alternatives. The production of the first iteration of new QD displays were planned to begin in 2021, and will be QD-enabled OLED, which uses organic material as the light source and QD material as a film. It will be more similar to Samsung’s own AMOLED used for mobile phones and LG’s OLED TVs and will mark the company’s return to the OLED segment.

Samsung Display have now released information (with a heavy dose of marketing) on their website about these new so-called “QD Display” panels (aka QD-OLED) It is not clear at this stage what segments this technology will be used in. We would expect the TV market to be the first with rumours of 55″ and 65″ models for next year, but it remains to be seen whether there is investment in to the monitor space. Time will tell.

What is a QD-Display?

Quantum Dots are very small semiconductor crystals that emit their own light, they create a wider variety of colors at wider angles. You might be familiar with QD technology being used in the desktop monitor market where a special coating (Quantum Dot coating) is often added to an LCD backlight to provide enhanced colours and wide colour gamut. In Samsung’s QD Display tech these are combined with a blue self-luminescent OLED layer (can also be Micro LED in the future), without the need for a backlight, allowing for the creation of rich colours and pixel level lighting and dimming capabilities.

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Super-fast response times

In an LCD display the individual liquid crystals of the panel have to move and re-orientate to control the level of light being passed through them from the backlight unit. This gives rise to the “response time” as we’re sure you’re all familiar with. The speed at which these crystals can move and change directly impacts the clarity of motion on moving content. However, in the QD Display, signals from the circuit directly produce light as needed in the QD light emitting layer, so it doesn’t need to spend much time controlling the light. This results in super-fast response times. QD Display’s fast response time can compose clean images without afterimage effects, even in videos with fast moving objects such as car racing or other sports. Just how fast these response times are remains to be tested, but OLED as a technology is well regarded in this area for near-instant, true <1ms G2G response times. We would hope for something similar here.

Pixel Level Dimming, True Blacks and 1 million:1 Contrast Ratio

In an LCD display with the backlight unit as the light source there is always some level of light that seeps through the panel layer, resulting in limited contrast ratios. This does vary by panel technology with monitor display TN Film and IPS panels often carrying a 1000:1 contrast ratio spec, and VA panels reaching up to around 3000:1 typically. This means blacks are not “true black” and in many cases users are disappointed by the handling of darker content.

The other problem with LCD backlights is that it is hard to provide a High Dynamic Range (HDR) image. For this to be offered you need to be able to improve the contrast ratio of the screen, and that requires “local dimming” of some sort. For LCD displays it is very difficult to introduce local dimming which would allow you to split the backlight up in to a number of zones, making it possible to dim darker areas, and raise the brightness of brighter areas. In the monitor market this is largely achieved by edge lit backlights with a very limited number of zones for the backlight. 8, 16, maybe 32 if you’re lucky. This can help a bit across the image as a whole but it’s limited in its capability and leaves issues like blooming and halos in practice. More advanced “Full Array Local Dimming” and Mini LED backlights are available in some places at a high cost, introducing far more zones (e.g. the very recent Asus ROG Swift PG32UQX – a 32″ 4K display with 1152 zones). These improve things massively over basic edge lit displays, but are still limited when you consider how many pixels actually make up that image (~8.3m on a 4K display). We would recommend a read of our HDR article for a lot more information on this, but creating an HDR display with LCD technology is difficult.

Unlike LCDs, but in a similar way to the widely-regarded OLED technology already common in the TV market, the blue light source of the QD display can control the light source of each individual pixel. QD displays with 4K resolution has about 8.3 million (3840 x 2160) light sources that can be controlled separately. This way, the QD display enables a high contrast ratio of 1,000,000:1 for perfect blacks to compose a deeper and more detailed image quality. This means pixel level local dimming, excellent HDR capability and the elimination of halos and blooming. This is one of the key benefits of OLED technology and Samsung’s QD Display tech will offer the same benefits.

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Images that feel brighter than they actually are

When you perceive the brightness of a display, you are not only seeing the actual physical brightness of the display, but also the expressiveness of blacks and color saturation. Even with the same luminance, the contrast looks different depending on the contrast of the background. The better the display shows the blacks, the brighter it looks. Also, the brightness feels different depending on the color type. The higher the saturation of the same color, the brighter it looks. But the QD display’s excellent expression of blacks and a broader range of colors makes the display look brighter than it actually is. Interestingly one of the earlier graphs also suggests a 1000 nits peak brightness which is a bit beyond current OLED panels (about 700 – 800 nits is common).

Reduction of harmful blue light

The QD display reduces “harmful blue light,” which can be dangerous to your eye health, by 40 to 50% over many LCDs, and Samsung claim on their website that this is the lowest level of all current displays. This is achieved by shifting the blue spectral peak to a higher wavelength and away from the 415-455nm area. The QD display’s blue light from the self-luminescent layer greatly reduces the portion of blue light when producing light, so it can be relatively safer from threats to your eye health. There is a push in the monitor market already from some manufacturers to do this same kind of thing, shifting the blue spectral peak as opposed to just making the image warmer through “low blue light” modes which have been around for many years but only reduce the peak height, they don’t change the wavelength.

The QD display has a very high degree of color purity of blue light produced from the blue light source, and the color purity of red and green that receive this light and form the QD device is high. With this high color purity, this technology has one of the broadest color expressions among current displays. Also, it can express a very broad range of colors at any brightness, from dark to light. Based on BT.2020 Color Volume, a typical large display has a color volume of less than 60%. But QD displays can express a color volume of above 80%.

Wide colour gamut and volume

The QD display has a very high degree of colour purity of blue light produced from the blue light source, and the color purity of red and green that receive this light and form the QD device is high thanks to the QD. With this high colour purity, this technology has one of the broadest color expressions among current displays. Also, it can express a very broad range of colors at any brightness, from dark to light. Based on BT.2020 Color Volume Samsung say that a typical large display has a color volume of less than 60%. But QD displays can express a color volume of above 80%. It remains to be seen what differences can be offered in colour gamut here, as there’s already a big push in this area from other technologies including LCD and OLED, but it looks clear that wide colour gamut coverage is a benefit of this technology anyway.

Wide Viewing Angles

QD emits light equally in all directions, minimizing the changes in image quality from different angles. At 60 degrees from the front, the luminance ratio from the front of conventional LCDs compared to their brightness is less than 40%. But for QD displays, it’s more than 70%, which is the smallest change in luminance at different viewing angles compared to other large displays. Basically the technology is capable of offering very wide viewing angles like OLED can.

Anti Reflection Coating

You may have been bothered by the sunlight coming through the windows, lights from the ceiling, fluorescent lights in stores, or other kinds of lights reflecting off of your display and obstructing your view. Displays that use glass as their material have this problem. The QD display reduces this reflection to its lowest level among all current displays (they claim) with Samsung Display’s reflection reduction technology, so you can see cleaner and clearer images where ever you go.


Source: Samsung Display


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