QD Tech May Be Key To Ultra HD Success

The promise of ATSC 3.0 delivering truer colors, brighter pictures and greater contrast under the umbrella of 4K Ultra HD doesn’t mean much to broadcasters if viewers don’t have an affordable way to watch it in their homes.

But a new technology known as quantum dots brings within reach affordable, mass market production of 4K UltraHD televisions that display purer colors and brighter pixels.

“QD [quantum dot technology] permits an upgrade to LCD without huge investments in new panel fabs,” says Paul Gray an analyst with IHS, formerly DisplaySearch. That in turn means consumers are likely to be able to afford 4K Ultra HD sooner than later.

Fortunately for broadcasters, 4K Ultra HD sets using quantum dots to deliver affordable HDR and wider color gamut are only now beginning to enter the marketplace. In January, Samsung unveiled its SUHD, which uses QD technology to boost performance, at the 2015 International CES and is now shipping.

More 4K Ultra HD sets with QD technology are expected to hit retail shelves in time for the holiday buying season.

While the timing doesn’t sync perfectly with the development of ATSC 3.0, which is due to be complete and accepted by the first half of 2017, it’s close enough to mean that at least a few million quantum dot TVs will already have been shipped in North America, according to a January 2014 DisplaySearch (now IHS) report.

While it is too soon to say definitively that ATSC 3.0 will include provisions for a wider color gamut and high dynamic range (HDR), things look favorable, says ATSC President Mark Richer.

“While nothing is final, it is very likely that ATSC 3.0 will include a wider color gamut, and it is likely to be within Rec. 2020,” he says.

Rec. 2020 refers to ITU-R Recommendation BT.2020, the International Telecommunication Union guidance made public in 2012 for various aspects of Ultra HD, including color space.

“Wider color gamut gets you more color accuracy — out much closer to the limits of human vision, and Rec. 2020 is beyond the limits of what TVs can actually reproduce today,” says Alan Stein, VP technology at Technicolor and chair of the ATSC S34-1 Ad Hoc Group on Video for ATSC 3.0.

“It’s future-proofing the color reproduction accuracy.”

At the Society for Information Display’s Display Week going on in San Jose, Calif., this week, quantum dot manufacturer Nanosys is demonstrating a QD-enhanced LCD panel covering 93.7% of the Rec. 2020 color gamut, says company spokesman Jeff Yurek.

“That’s a real breakthrough. There’s no other technology that can do that today.”

IHS’s Gray isn’t willing to go quite that far, however. “QD LCD allows near-OLED [performance] at a price close to LCD,” he says.

Where QD may not achieve the same level of OLED is in color saturation — not due to a deficiency in the quantum dot technology but rather to inherent light leakage of LCD panels on black pixels, he explains.

However, OLED is not yet a “proven mass market technology” and QD technology will make other benefits possible, such as high dynamic range, an essential requirement “for a true UHD experience,” says Gray.

OLEDs will always be playing “catch up” in terms of light output — an important component of delivering high dynamic range — as compared to LCDs, says Gray.

That’s because light has to pass through the electronics driving OLED pixels as opposed to LCD pixels which simply act as shutters, he explains.

Samsung’s SUHD televisions illustrate the advantage QD technology delivers in terms of light output, Yurek says. The sets, which use quantum dot technology licensed from Nanosys, achieve a peak brightness of 1000 nits, 2.5 times brighter than the typical TV today, he says.

So important is high dynamic range, that it is the first things consumers are likely to notice when they walk into the electronics department of a retailer and see TVs sitting side by side, Stein says.

“HDR is more universally visible. You will always see a brighter picture with more contrast and detail,” he says.

Quantum dot technology allows LCD panels to deliver both higher dynamic range and a wider color gamut, Yurek says.

“The quality of the color and the brightness of an LCD is a function of the backlight,” he explains.

Quantum dots — tiny semiconductor nanocrystals smaller than a virus — are “the world’s most efficient light emitting material,” Yurek says. In a 4K Ultra HD LCD television, they are dispersed on a film that sits between a blue LED light source and the LCD assembly.

“What they do is take short wavelength light, like a blue light, and convert it into other wavelengths of light. Those wavelengths are determined by the size of the crystal,” he explains.

Certain nanocrystals applied to the film are “tuned” to convert blue light from the LED source into a precise red and other crystals transform the light into a precise green.

“We pass through some of the blue and that gives you red, green and blue for the LCD display,” Yurek says.

The LCD portion of the display — including the liquid crystal layer and polarizers — remains the same, although in a 4K television there would be far more pixels

That’s why Yurek calls the QD technology a “drop-in” that leaves the display otherwise unaffected from a manufacturing point of view and Gray says the technology is suited for the long-established LCD TV production process.

Nanosys is one of a handful of companies that manufacture quantum dot material. 3M is using a QD slurry manufactured at the Nanosys fab in Silicon Valley, Calif., to make the quantum dot film that will be used in televisions, says Yurek.

QD technology isn’t just for consumers, however. At Display Week 2014, Dolby Labs introduced a 32-inch Dolby Vision reference monitor using Nanosys QD technology.

Dolby is using the monitor to develop content for its Dolby Vision, the company’s take on a brighter, higher-contrast, wider-color-gamut television system.

Yurek says the reference monitor demonstrates that QD technology will be suited to the needs of broadcasters for reference and production monitors in the future.

As for the broader consumer market, IHS’s Gray says consumer adoption of 4K Ultra HD televisions delivering a wider color gamut and HDR with the assistance of QD technology depends in large measure on broadcasters.

“This [consumer uptake] depends hugely on the standards adopted by broadcasters for UHD and the on-cost of deep color solutions,” he says. “However I expect that deep color will be an indispensable feature on high-end TVs in the next two years.”

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