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.


5 thoughts on “Is the rec.2020 UHD color broadcast spec really practical?

  1. 97% of Rec. 2020. Wow! Congrats to the engineers at Nanosys, that is quite the achievement!

    While LG’s OLED has good color, an LED TV with a 97% Rec 2020 QDEF would blow that out of the water. Add some Full Array Local Dimming and you can even get great blacks too.

    The next time you meet with HiSense can you please tell them they can eat Samsung/LG for breakfast with the following simple recipe:

    8K LCD
    240 Hz
    97% Rec 2020 QDEF
    384 or more Zone FALD
    800 nits of Brightness
    Option to turn off all internal processing for least possible input lag.
    DisplayPort 1.3 or Thunderbolt 3, HDMI 2
    VESA Adaptive-Snyc

    You make that display in sizes ranging from 20″ – 110″ and you have a money printing machine.
    Heck even 4K, 10-bit, DP 1.2 would also do it.

    Hope you guys can get your new 97% Rec 2020 QDEF solution to the market soon.
    You can bet every color grader in the world would buy a display with that immediately both at work and at home.

  2. What about OLED, couldn’t it be possible to reach rec. 2020 using OLEDs? The samsung oled tv has a pretty wide color space.

    • OLEDs are capable of producing wide color gamuts compared to white LED LCDs however, there are two primary issues which OLED has some difficulty with when it comes to rec.2020: OLED is so far not able to reproduce primary colors that are saturated enough to cover rec.2020 and the efficiency or brightness would be much less for an OLED which is often times an unacceptable design tradeoff for display makers.

      • OLED is a new technology and it does have some issues I agree with the brightness and efficiency. However the contrast and reponse times could make up for it if the technology can mature enough to reach the rec. 2020 color range.

        However, I thought that Plasma, OLED and RGB LED had better color range than Quantum dots due to direct color from each subpixel opposed to color filters and quantum dots?

      • Quantum Dots can reproduce a wider color gamut than OLED or PDP or even RGB LED. They can be tuned to produce any wavelength of light in the visible spectrum and they are extremely efficient light emitters. This makes them a great fit for color filters actually because they can reproduce a wider range of color without needing a very tight cut-off filter. The efficiency makes it possible to choose very deep, saturated primary colors without losing brightness.

        This is a big difference compared to other technologies where you might be able to recreate a deep red but not do so as efficiently or with as much brightness as QD enables. So QDs make it practical to produce devices with wider color gamuts than ever before.

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