Samsung's QD-OLED TV tech explained: Welcome to the quantum dot era

The quantum dot era of OLED TVs began Tuesday with the debut at CES 2022 of Samsung's first QD OLED TV screens and computer monitors. This new display technology, which Samsung calls QD Display, promises to improve image quality for top-tier products, which is good news for big-budget buyers who want the richest colors in their home theaters.

Samsung promises several image quality improvements compared with existing OLED TVs and monitors: higher brightness in highlights, better color in bright areas where conventional OLED displays wash out to a whiter color, better color in dim areas where shadows can swallow richer hues, and no dimming or color shifts for people viewing a TV at an angle. Blacks are deep, and for fast-changing scenes or video games, there's minimal ghosting that can blur the edges of moving elements.

It's not just a research project. Samsung will sell a QD Display TV later this year, and Sony announced its own 2022 QD-OLED models on Tuesday.

I visited Samsung Display's campus in San Jose, California, to see the panels firsthand and compare their performance to two display alternatives, OLED and LCD boosted with local-dimming technology. Even though it was a Samsung-arranged comparison and not an instrumented test of all display quality attributes, I'd say Samsung has a real chance at unseating the image quality leader, OLED.

It'll all come at a cost though. QD OLED displays will occupy a premium segment of the market. If you can't afford an OLED TV from a company like LG or Sony today, you're unlikely to find a QD OLED-based TV any more palatable.

Samsung Display, the division of the South Korean giant that manufactures the new panels, has three QD Display panels: 55-inch and 65-inch options for 4K TVs and a 34-inch option for computer monitors at QHD+ (3,200x1,800-pixel) resolution. It sells them to other companies but didn't reveal in advance which companies will use the panels or whether TV powerhouse Samsung Electronics is on the list.

When it comes to QD OLED, Samsung is the only game in town right now. Even though it's an electronics colossus, expect QD OLED's higher costs to confine the technology to the premium market. And competitor LG has about six times the OLED manufacturing capacity as Samsung's QD OLED production, said Ross Young, founder of Display Supply Chain Consultants.

"Given the low volume, [QD OLED] will be an ever smaller niche" than OLED, Young said. "LCDs will remain the volume and value leader for more than five years."

If you care about image quality and are willing to pay, though, QD OLED will be worth a look.

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How do QD OLED displays work?

I'll get to QD OLED TVs, but let's take a couple steps through history to get there.

Ever since color TVs were invented, the trick has been generating a grid consisting of patches of red, green and blue light. One of the best ways to do that has been with ever-smaller electronic components called light-emitting diodes, or LEDs. The first were red, but now LEDs can emit blue, green, white and other colors of light.

Prevailing LCD technology generates white light with an LED backlight. An electronic layer -- the liquid crystal part of the term LCD -- lets through a specific combination of red, green and blue light for each pixel. The full array of 3,820x2,160 pixels in a 4K TV, updated 30 or more times per second, creates the moving imagery you see on the TV screen.

A newer type of display uses a variation of the basic electronic component, the organic LED, or OLED. Instead of relying on a backlight, each pixel is made of individual OLEDs that directly emit light. Those OLEDs can switch off entirely for deeper blacks than LCDs, which can look a bit gray when some of the backlight's rays leak through the filter. However, OLED TV technology isn't as bright, so it's typically boosted with a white LED for bright areas. That's why current OLED TV displays, including the one manufactured by LG and sold by LG, Sony and Vizio in the US, are often called WOLED or WRGB OLED.

OK, now to Samsung's QD OLED technology.

It relies on a combination of OLEDs and quantum dots, tiny particles of semiconducting material that Samsung sources from a specialized supplier. When quantum dots are illuminated by a particular frequency of light, their atoms' electrons jump into a higher state of energetic excitement. It's only fleeting, though, and when the electron drops down to the lower state, the atom releases light. Tuning the quantum dot sizes changes the frequency of light they emit.

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To generate blue light, QD OLED displays just use a regular OLED.

For red and green light, though, other blue OLEDs illuminate two varieties of quantum dots. One patch releases green light and another releases red light. Samsung uses a higher-tech version of an inkjet printer to carefully place the quantum dot on its display substrates.

Higher brightness, better color, Samsung says

The result is, in Samsung's view, the best of both worlds. With no reliance on white LEDs, QD OLED displays can show bright colors that remain vivid. They also fare better with darker colors, the company says. Samsung also tunes dispersion characteristics so the screens can maintain better image fidelity when viewed from the side at extreme angles.

My tests showed Samsung wasn't blowing smoke -- at least for the unnamed comparison panels Samsung set up. The company insisted they were high-end models and showed them in a darkened room to best flatter the displays' performance.

It seemed to me the QD OLED highlights were indeed more colorful than on the OLED or LCD displays. And it handily beat the LCD for dark scenes with bright lights, where the LCD's local-dimming LEDs left halos glowing around the bright regions.

In a separate test of the TVs in a brighter room, the QD OLED TV was slightly less troubled by room reflections than the OLED and much less troubled than the LCD.

And in a third test, the QD OLED computer monitor showed less ghosting with moving images than a rival display.

QD OLED TVs will have to prove themselves in more thorough testing -- in particular how well they compare to LCDs with bright imagery -- and I'm eager to hear the opinions of TV experts like my colleague David Katzmaier. It's worth mentioning that these test panels set up by Samsung Display might differ from the actual QD OLED TVs that'll be available to buy, and that the demo material Samsung chose almost certainly shows the advantages of QD Display more clearly than real-world TV shows, movies and games will.

Like all OLED displays, Samsung's QD Display products will suffer from some burn-in issues. Samsung says it's still running tests to assess long-term performance, but it promises the QD Display products will meet or beat OLED rivals in longevity. And it can deal with the problem by monitoring each pixel's performance and adjusting its behavior, a new technology it calls real-time image sticking compensation. According to Samsung, that's better than rivals' manual process that takes 15 or 20 minutes.

Samsung QD Display by the numbers

Samsung did offer some statistics. Overall brightness is 200 nits for the full TV screen, 1,000 nits for a 10% patch and 1,500 nits for a 3% patch. By comparison, we've measured about 800 nits for the industry standard 10% patch with the LG C1 OLED TV, so by that measure the QD Display can get 25% brighter. Meanwhile the brightest LCD TVs hit more than 2,000 nits with a 10% patch, and the brightness advantage of LCD is even greater at full screen. 

In terms of color gamut, the QD OLED TVs reach 99.8% of the P3 color space, which is basically the same as standard OLED TVs we've measured. Samsung claims a bigger advantage with the wider BT2020 color space (90.3% vs 77.4%), but that test isn't widely used yet. The computer monitor reaches 99.3% of P3 color and 80.7% of BT2020 color.

QD OLED displays have some other limits. They don't have small enough pixels, at least yet, to support phones, laptops or TVs with monster 8K resolution. But Samsung says it's working on improvements that'll permit the latter.

But for now, Samsung has a better competitive response to LG's OLED TVs. And even if it isn't likely to push workhorse LCDs aside, premium TV revenue is increasing, Young said. "If they can demonstrate better performance, I am sure they will do well."