Tag Archives: quantum dot

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

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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.

Adobe’s Kuler color app is a great tool for designers but is your display accurate enough for it?

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Screenshot of Adobe's Kuler app showing color extraction from a photo

Screenshot of Adobe’s Kuler app showing color extraction from a photo

Adobe recently released a new iPhone app called Kuler that let’s you extract colors from your surroundings using the phone’s camera. It’s a useful tool that allows designers to capture color inspiration wherever they find it and easily incorporate it into their work via color palettes.

The app also highlights a weakness in current display technology: no display on the market today can actually reproduce all the colors we see in the environment around us. So, even if the camera sensor can capture that color you love, you may not be seeing an accurate representation of it on your device.

The iPhone 5’s LCD display is designed to cover the sRGB/rec.709 color gamut standard used for HDTV broadcasts. And, it looks great but compared to the world we see around us, it’s just not quite as rich. If we plot the iPhone 5’s color gamut against the gamut of colors found in nature, the phone comes up short in important reds, greens and cyans:

Color gamut of the iPhone 5's display compared to the gamut of colors found in nature. The iPhone 5 comes up short in red, green and cyan.

Color gamut of the iPhone 5’s display compared to the gamut of colors found in nature. The iPhone 5 comes up short in red, green and cyan.

If DisplayWeek 2013 was any indication, color has once again become a hot topic in the display industry. Color gamuts are getting larger and it may not be long before we see a display that can match what our eye sees in nature. Over the course of the next year, we will start to see more wide color gamut-capable devices as OLED continues to expand marketshare and new technologies like quantum dot LCD begin to enter the market in volume.

DisplayWeek 2013: Color is back

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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.

DisplayDaily: Is quantum dot lifetime good enough for TV?

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Ken Werner of Display Central has a post comparing the benefits of quantum dots to OLEDs in consumer TV applications.  Being the authority on quantum dot displays that we are here at Nanosys, Ken contacted us for an analysis.  Here is the explanation our Ph.Ds gave Ken:

OLEDs use organometalic compounds to emit light. They typically have a central metal atom surrounded by organic ligands. The decay issues are the same as with typical organic fluorophores.  In the excited state these molecules are very reactive to H2O and O2, as well as other small molecules that may be around. Once they react they become a different molecule and they will no longer fluoresce or phosphoresce and give off light. The more blue the light emission, the higher the energy of the excited state, and the more reactive the excited molecule will be. So your blue organic phosphores will have a much shorter lifetime than will red phosphores. The burn-in problem seen in OLED displays, that can be seen after just several weeks of operation with static content, is a manifestation of early blue degradation compared to green and red.

Conventional phosphores like YAG are doped materials. YAG used in white LEDs is actually cerium doped YAG. The cerium atom emits the yellow light and is surrounded by a vast amount of YAG. Quantum dots are similar in that a central core crystalline semiconductor material is used to confine the holes and electrons of the exciton (analogous to the cerium in YAG), and in our material this is surrounded by a thick shell of a different, lattice-matched semiconductor material (analogous to the YAG.) We call this a core-shell Quantum Dot structure. If the lifetime of our materials is less than that of conventional phosphors, it is typically because we have not made a perfectly lattice-matched shell, which may distort the core and cause defects at the core/shell interface that reduces the quantum yield.

The big difference here is that a perfectly made core-shell quantum dot does not have an intrinsic lifetime failure mechanism, whereas the organometallic compounds are intrinsically reactive to their environment, which makes them prone to shorter lifetimes especially at higher energies such as blue.

This is an important discussion, because TVs are a harsh environment for display components, running much hotter and brighter than tablets or mobile phones.  You can read the entire post here: http://www.display-central.com/flat-panel/is-quantum-dot-lifetime-good-enough-for-tv/

CES 2012: more colorful displays on the horizon

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If there is one thing we can take away from CES this year, it’s that displays with better color performance are on the horizon. Two of the largest attention getters at CES this year were new displays by Sony and LG.  LG unveiled a 55″ OLED and Sony displayed a new “Crystal LED” technology.  While both of these displays exhibited impressive performance, including a wider color gamut, the Sony TV was a prototype only, and the LG display is expected to be available later in the year at a hefty price.

As Hubert of Ubergizmo points out, these technologies offer great promise, however, cost will be their determining factor.  OLED, which has been on the horizon for what seems like forever, still looks like it will not be available to the masses for quite a while, certainly not in large formats and not at a manageable price point for the consumer.

By contrast, QDEF, offers an affordable, consumer ready solution today. Display designers who are looking for the next new thing will find that they can have a screen with high brightness, deep color, high-DPI resolution and deep blacks in a display that’s as big as they want using QDEF with no increase in cost. This is because QDEF has been designed as a drop-in diffuser sheet replacement to leverage the billions of dollars of existing installed manufacturing capacity and two-plus decades of improvements to LCD performance.  With QDEF, manufacturers can easily replace the diffuser sheet in their displays with a sheet of QDEF and gain over 100% of NTSC color performance.

QDEF at CES 2012

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I attended CES 2012 in Las Vegas earlier this month where I spent most of the week showing off a pair of QDEF-hacked iPads.  Also found some time got to check out some other high color performance display technology and I’ll have more on that in a later post. For now, here’s a quick review of a couple QDEF coverage highlights from CES:

First up is a video interview I did with Bill Wong from Electronic Design. It was great to see these guys again and do a bit of deeper dive on the quantum dot nanotechnology that makes QDEF go:

EngineeringTV CES 2012 Interview

I also ran into Jaymi Heimbuch of Treehuger about QDEF’s ability to improve the performance of LCD displays while using less energy and requiring far less capex than OLED:

The technology is as energy efficient as LED technology, which means it is way ahead of OLEDs right now which offer beautiful displays but not necessarily a constant energy savings. In other words, while the future of OLEDs may seem bright (and companies like Samsung are still pursuing OLED displays while others like Sony have dropped out of the race), the future of LEDs is already here and the technology from Nanosys can mean vast improvements without much effort.

You can read the article in its entirety here: Treehugger.com

It was exciting to see the newest and best new technology available, and I can’t wait until we get to see some of these gadgets and electronic devices outfitted with QDEF displays.

Record Smashing Sales of Video games like Activision’s Call of Duty will drive sales of high color gamut displays

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If you ever doubted that video games are big business Activision’s recent sales record should be enough to convince you. On its way to reaching $1 billion in sales in just over two weeks with Call of Duty: Modern Warfare 3, Activision smashed every entertainment sales record.

Every entertainment sales record.

That means books, movies and video games. Over its lifetime the franchise has generated in the neighborhood of $6 billion in revenue, which puts it squarely into a Star Wars-level stratosphere as one of the most valuable entertainment properties ever.

What does this have to do with high gamut color display technology?

One of the potential hurdles to widespread adoption of high color gamut display technologies is a lack of content that’s optimized to take advantage of all those extra colors.

With Hollywood-sized blockbuster sales comes Hollywood-sized budgets to create rich new universes for gamers to explore. The expanded creative palette that high color gamut technology offers game developers is a perfect fit. What color is the blood of a martian supposed to be when it explodes and why limit it to a range of colors typically seen on earth?

Additionally, on the platform side, electronics manufacturers could take advantage of a push into high gamut displays to differentiate their entire hardware/software ecosystem. We already know that the current PlayStation™ hardware is capable of the xvColor high gamut standard. Pairing that with wide color games and a TV that can show it might prove a useful differentiator for any platform.

Videogames may just be the driving force that finally pushes high gamut displays into the mainstream.