Is the rec.2020 UHD color broadcast spec really practical?

I’ve often advocated on this blog for Pointer’s Gamut as an important design goal for display makers but is it really practical today from a technology perspective? Pointer’s Gamut covers a huge area and it’s odd shape makes it awfully difficult to cover with just three primaries. Rec.2020, the leading Pointer’s-covering color gamut broadcast standard and de facto standard for upcoming UHD broadcasts, demonstrates this perfectly. It uses very deep red and green primaries to ensure that all those purples and cyans can get squeezed it into the triangle.

rec.2020 needs a very deep green to cover 99.9% of Pointer's Gamut

rec.2020 needs a very deep green to cover 99.9% of Pointer’s Gamut

It’s certainly tough to make a display that can reproduce primary colors that are that saturated and it is especially hard to do so efficienctly. Until now the displays that have come closest rely on an esoteric and power-hungry laser backlight system that can only cover up to about 91% of rec.2020 spec. That is impressive given how ambitious rec.2020 is but a bulky $6,000 laser display doesn’t exactly qualify as practical and it’s certainly not a technology that we are likely to find in a tablet or smartphone anytime soon given it’s low power efficiency.

That may be about to change.

My company, Nanosys, has been working on this problem and we now think it is practical to produce an LED LCD that covers over 97% of rec.2020 using Quantum Dot technology. The latest generation of our Quantum Dots emit light with a very narrow Full Width Half Max (FWHM) spec of below 30 nanometers for both red and green wavelengths. FWHM is pretty obscure spec to be sure but it means that the color is both very pure and accurate. That pin-point accuracy actually enabled us to demonstrate over 91% rec.2020 just by modifying an off-the-shelf, standard LCD TV set with a specially tuned sheet of Quantum Dot Enhancement Film (QDEF).

Nanosys demonstrates over 91% coverage of rec.2020 using Quantum Dots

Nanosys demonstrates over 91% coverage of rec.2020 using Quantum Dots and a standard LCD TV color filter

Very impressive and even a bit better than the performance of that laser TV but still not quite all the way there. What else could be optimized to improve the system and get us closer?

Looking at the spectrum after the color filters revealed a significant amount of blue leaking through the green filter. This leakage was causing the blue point to shift away from the rec.2020 primary. By optimizing the system and selecting a different blue color filter material with a sharper cutoff, Nanosys engineers showed that it is possible to build a display that covers over 97% of the rec.2020 standard– with great power efficiency.

Quantum Dot enhanced displays are in mass production today, they are used in commonly available displays on the market today. Their high power efficiency also means they can be used in all kinds of devices from smartphones to TVs. So, for the first time, it is actually becoming practical to build displays that cover the massive rec.2020 standard and since rec.2020 is part of the UHD broadcast spec this great news for the next generation of 4K and 8K devices.

CES 2014 Display Wrap-Up

CES 2014 has come to a close and while many predicted a lackluster year, there were actually a number of interesting developments in displays. These are my top three CES 2014 display technology takeaways:

CES 2014 85" Hisense QDTV

4K is here now, content isn’t the issue anymore

Analysts are still having a tough time figuring out exactly how quickly 4K will be adopted. According to data presented by the LCD TV Association at the show, last year analysts thought we’d see about 2 million 4K sets in 2014. Actual numbers turned out to be about 13 million (with 10 million predicted in China alone). 4K is clearly happening faster than most predicted but, if anyone still doubted that 4K will be mainstream in the next couple of years, this year’s CES should have made it clear that its here today.

Just about every major set maker showed off 4K sets this year in every flavor imaginable from LCD to OLED. But, hardware has never been the real barrier to 4K adoption– it’s all about the content or lack thereof. At CES 2014, the content issue was resolved a couple of different ways: Netflix is making 4K delivery a priority and upscaling is starting to look really good. With great upscaling (in one demo I saw from Technicolor it was nearly impossible to pick native 4K from upscaled 1080P) and instantly available content from Netflix, I don’t think content availability will continue to be a barrier for 4K adoption.

Wide Color Gamut and High Dynamic Range

Both Dolby and Technicolor demonstrated some very impressive high dynamic range and wide color gamut technologies that make for much more immersive viewing experiences. With it’s new Dolby Vision technology, Dolby has created essentially a new standard that uses a layer of metadata on top of today’s broadcast standard to deliver wider gamut and dynamic range with the content creator’s intentions intact. This is significant because it won’t require a new broadcast standard. Much like their surround-sound offerings (which deliver stereo audio if you have two speakers and full surround if you have six), all you’ll need is a Dolby-capable set to see the advantages, it won’t be something the viewer has to worry about.

Similarly, Technicolor is doing some on-the-fly processing to incoming content in realtime to pull out extra dynamic range and color. Again, no change in broadcast standard required for this and that’s the key. While there’s some danger that artistic intent will be altered with this approach, the demos I saw looked great. Skin tones and memory colors were kept in check while still taking advantage of the extra saturation offered by a wide color gamut display.

Quantum Dots

One of the most impressive displays at CES 2014 was Hisense’s 85″ 4K wide color gamut Quantum Dot TV. This set promises to bring OLED-like color performance at 4K resolutions to the US market this September at LCD prices (we heard a 55″, 65″ and the 85″ will all be offered). A number of other manufacturers also demonstrated Quantum Dot displays off the main show floor. We saw displays ranging in size from 5″ smartphones, to notebooks to monitors as well as TV’s. 2014 looks to be the year that Quantum Dots gain serious traction in the display market after a strong debut in 2013.

DisplayWeek 2013: Color is back

Just back from a great DisplayWeek in Vancouver. Finally had a chance to recover, go through my notes and process everything I saw at the show. Most of the big story lines will be pretty familiar to anyone who followed last years show: TV’s are still getting bigger, OLED TV is still right around the corner, 4K is starting to ship and mobile displays are getting both sharper and more efficient.

DisplayWeek wasn’t all old news though. In fact, just like CES, this year everyone seemed to be talking about color performance. At the annual Display Industry Awards, honors in several categories went to wide gamut display technologies including the Best In Show and Component of the Year awards. And, on the show floor, major manufacturers like 3M, Samsung and LG dedicated significant booth space to wide color gamut or color management technologies.

3M's Quantum Dot Enhancement Film demo at DisplayWeek 2013. Bottom display is using quantum dots to achieve a wide color gamut.

3M’s Quantum Dot Enhancement Film (QDEF) demo at DisplayWeek 2013. Bottom display is using quantum dots to achieve a wider color gamut than OLED at higher brightness and lower cost.

3M demoed several wide color gamut LCDs  based on the Quantum Dot Enhancement Film (QDEF) technology that they are partnering with Nanosys to manufacture. Ranging from smartphone all the way up to 55″ TVs in size, these devices were all showing a wider color gamut than OLED with an especially deep red. This seems like a lot of color but 3M says that in developing their Perceptual Quality Metric (PQM), a new analysis tool aimed at helping display makers model how different performance characteristics will affect end user experience, they found that color saturation positively affected the perception of quality.

In Samsung’s neighboring booth, I found a series of comparison demos designed to show that wide color gamut displays can be both accurate and pleasing to the eye. Each demo featured a camera feeding a live image of several colored objects to both standard and wide color gamut displays. In each case the wide gamut display was able to more accurately recreate the color of the objects in front of the camera. They also showed off the new color management capability of their flagship Galaxy S4 smartphone that allows the device to accurately display rec.709 content without oversaturation- something the previous generation S3 struggled with.

Samsung demonstrating the value of wide gamut displays by showing some common colors that fall outside the rec.709 broadcast gamut standard in a series of demos at DisplayWeek 2013

Samsung demonstrating the value of wide gamut displays by showing some common colors that fall outside the rec.709 broadcast gamut standard in a series of demos at DisplayWeek 2013

Finally, at LG’s booth, we saw a new LCD color filter design that allows them to cover the Adobe RGB color gamut used by photographers and print professionals.

With all of this buzz, it looks like we’ll start to see wide color gamut displays start to move into the mainstream in ever larger screen sizes over the next half of this year and into 2014.