What Are Quantum Dots, and Why Do I Want Them in My TV?

Quantum dots glow a specific color when they are hit with any kind of light. Here, a vial of green quantum dots are activated by a blue LED backlight system.

If you look at the CES 2015 word cloud—a neon blob of buzz radiating from the Nevada desert, visible from space—much of it is a retweet of last year’s list. Wearables. 4K. The Internet of Things, still unbowed by its stupid name. Connected cars. HDR. Curved everything. It’s the same-old, same-old, huddled together for their annual #usie at the butt-end of a selfie stick.

But there at the margin, ready to photobomb the shot, is the new kid: quantum dot. It goes by other names, too, which is confusing, and we’ll get to that in a minute. Regardless of what you call it, QD was all over CES this year, rubbing shoulders with the 4K crowd. You may have heard people say it’s all hype. Those people can go pound sand. Quantum dot is gonna be the next big thing in TVs‎, bringing better image quality to cheaper sets.

A Quantum-Dot TV Is an LCD TV

The first thing to know is quantum-dot televisions are a new type of LED-backlit LCD TV. The image is created just like it is on an LCD screen, but quantum-dot technology enhances the color.

On an LCD TV, you have a backlight system, which is a bank of LEDs mounted at the edge of the screen or immediately behind it. That light is diffused, directed by a light-guide plate and beamed through a polarized filter. The photons then hit a layer of liquid crystals that either block the light or allow it to pass through a second polarized filter.

Before it gets to that second polarizer, light passes through a layer of red, blue, and green (and sometimes yellow) color filters. These are the subpixels. Electrical charges applied to the subpixels moderate the blend of colored light visible on the other side. This light cocktail creates the color value of each pixel on the screen.

With a quantum-dot set, there are no major changes to that process. The same pros and cons cited for LCD TVs also apply. You can have full-array backlit quantum-dot sets with local-dimming technology (Translation: good for image uniformity and deeper blacks). There can be edge-lit quantum-dot sets with no local dimming (Translation: thinner, but you may see light banding and grayer blacks). You can have 1080p quantum-dot sets, but you’re more likely to see only 4K quantum-dot sets because of the industry’s big push toward UltraHD/4K resolution.

But a Quantum-Dot TV Is Different

In a quantum-dot set, the changes start with the color of the backlight. The LEDs in most LCD TVs emit white light, but those in quantum-dot televisions emit blue light. Both types actually use blue LEDs, but they’re coated with yellow phosphor in normal LCD televisions and therefore emit white light.

Here’s where the quantum dots come in. The blue LED light drives the blue hues of the picture, but red and green light is created by the quantum dots. The quantum dots are either arranged in a tube—a “quantum rail”—adjacent to the LEDs or in a sheet of film atop the light-guide plate.

Quantum dots have one job, and that is to emit one color. They excel at this. When a quantum dot is struck by light, it glows with a very specific color that can be finely tuned. When those blue LEDs shine on the quantum dots, the dots glow with the intensity of angry fireflies.

“Blue is an important part of the spectrum, and it’s the highest-energy portion—greater than red or green,” explains John Volkmann, chief marketing officer at QD Vision, which makes quantum dots for several TVs and monitors. “You start with high energy light and refract it to a lower energy state to create red or green… Starting with red or green would be pushing a rock uphill.”

Quantum dots are tiny, and their size determines their color. There are two sizes of dots in these TVs. The “big” ones glow red, and they have a diameter of about 50 atoms. The smaller ones, which glow green, have a diameter of about 30 atoms. There are billions of them in a quantum-dot TV.

If you observed quantum-dot light with a spectrometer, you would see a very sharp and narrow emission peak. Translation: Pure red and pure green light, which travels with the blue light through the polarizers, liquid crystals, and color filters.

Because that colored light is the good stuff, quantum dots have an advantage over traditional LCD TVs when it comes to vivid hues and color gamut. In a normal LCD, white light produced by the LEDs has a wider spectrum. It’s kind of dirty, with a lot of light falling in a color range unusable by the set’s color filters.

“A filter is a very lossy thing,” says Nanosys President and CEO Jason Hartlove. Nanosys makes film-based quantum-dot systems for several products. “When you purify the color using a color filter, then you will get practically no transmission through the filter. The purer the color you start with, the more relaxed the filter function can be. That translates directly to efficiency.”

So with a quantum-dot set, there is very little wasted light. You can get brighter, more-saturated, and more-accurate colors. The sets I saw in person at CES 2015 certainly looked punchier than your average LCD.

That Sounds Expensive

There’s no doubt that quantum-dot TVs will cost more than normal LCDs—especially because they’re likely to be 4K sets. But quantum-dot is getting a lot of buzz because its cheaper than OLED.

In most peoples’ eyes, OLED TVs are the best tech available. But they’re expensive to build and expensive to buy—you’re looking at $3,500 to as much as $20,000—and the manufacturing process differs in several key ways. That’s a big reason LG is the only company putting big money into building them.

Conversely, quantum-dot sets don’t require overhauling the LCD fabrication process, and they produce a much wider color gamut than traditional LCDs. They’re closer to OLED in color performance, and they also can get brighter. That’s important for HDR video.

“The attraction to the OEM is that this is a pure drop-in solution,” says Nanoco CEO Michael Edelman, whose company makes quantum-dot film in a licensing deal with Dow Chemical. “They remove a diffuser sheet in front of the light-guide plate and replace it with quantum-dot film. Nothing in the supply chain gets changed, nothing in the factory gets changed. They get, in some cases, better than OLED-type color at a fraction of the cost.”

As you’d expect, companies making film-based and tube-based solutions are touting each approach as superior. QD Vision claims its tube-based approach is easier and cheaper to implement, and it can boost the color performance of cheaper edge-lit LCD sets. According to QD Vision, the oxygen-barrier film needed for film-based dots is costly, which explains why Nanoco and Nanosys are partnering with Dow and 3M for that film.

Film-based suppliers say their method has the upper hand due to “light coupling,” or the ability to feed all that quantum-dot light directly into a light-guide plate. The film layer also purportedly works better with full-array backlight systems, which will be used in a lot of UHD and HDR TVs.

Super! So This Is OLED for Less Money?

Not entirely. Color gamut is important, but it’s only one aspect of picture quality. Because these are LCD sets, they won’t have the blackest blacks, super-wide viewing angles, and amazing contrast of OLED. And while the extra brightness and saturation makes onscreen colors really pop, all that luminance may create light bleeding.

Some quantum dots also contain cadmium, which is toxic at high levels—think “factory emission” levels rather than “sealed tube or film in your TV” levels. Still, there are health and environmental concerns, especially if a bunch of quantum-dot TVs end up in landfills. The European Union restricts the use of cadmium in household appliances. Some quantum-dot producers are marketing their product as cadmium-free. QD Vision, which supplies quantum dots for TCL’s new flagship 4K TV, Sony’s well-reviewed 2013 Triluminos sets, and Philips and AOC monitors, still uses cadmium.

“There are only a couple of materials that deliver on the promise of quantum dots,” says QD Vision’s Volkmann. “The other is based on indium. Cadmium is superior with respect to delivering higher-quality color, meaning a broader color gamut. But also much more energy-efficient at converting blue light to other forms of light that allow you to fill out that spectrum. The folks making indium-based solutions like to paint cadmium as the bad guy… Cadmium is under observation by different regulatory agencies around the world, but it turns out indium is too.”

Nanosys, which produces both cadmium and cadmium-free quantum dots, agrees that cadmium-based dots are more efficient.

“Cadmium-based materials have a narrower spectral width,” says Nanosys’s Hartlove. “More pure color. And what that means is the other things the system has to do in order to keep that color pure, the burden on the rest of the system is reduced.”

Hartlove also says that cadmium may be a greener solution. The cad selenide crystal used in quantum dots isn’t as toxic as pure metallic cadmium, and the efficiency of their color-producing ways has benefits.

“The type of power we generate in the US from coal-based power plants throws cadmium into the atmosphere,” says Hartlove. “That’s one of the byproducts of burning coal. And you look at the net cadmium content over this whole lifecycle, and it turns out that cadmium sequestration is actually net better for the environment.”

Why Isn’t Everybody Calling It “Quantum Dot”?

Each manufacturer with a quantum-dot TV set seemingly has a different name for the technology. Samsung likes “nano-crystal semiconductors.” Sony has new Triluminos TVs that “incorporate the same benefits as quantum dots.” LG, TCL, Hisense, and Changhong are actually calling it quantum dot, which is nice.

“The term quantum dot is generic,” says Hartlove. “Each company kind of wants to grab this for their own and brand it their own way. That will probably lead to some consumer confusion… but I think most of the industry will converge on a way to describe this technology.”

There are slight differences between the technologies everyone’s using, but they’re variations on a theme. The differences center on whether the TVs are edge-lit or back-lit with quantum dots, and whether the systems use cadmium- or indium-based quantum dots.

Who Is Making Quantum Dots?

At this stage, three companies are the big players in the quantum-dot TV landscape.

QD Vision specializes in glass-tube “edge-lit” components, and its systems will be found in TCL TVs and monitors from Philips and AOC. It supplied the quantum-dot component for Sony’s 2013 Triluminos sets, but Sony recently ditched the company in favor of another.

Nanoco focuses on cadmium-free, film-based quantum dot systems. They have a licensing deal with Dow Chemical, and Dow is currently building a factory in South Korea to ramp up production of quantum-dot film. Nanoco’s cadmium-free technology will be found in LG’s quantum-dot TVs in 2015.

Nanosys is another film-based producer that has partnered with 3M on the film-sheet tech. It makes both cadmium-based and cadmium-free quantum dots. They are the company behind Amazon’s HDX 7 display and the Asus Zenbook NX500, and Samsung licenses the cadmium-free quantum-dot tech in its new SUHD 4K sets from Nanosys. Nanosys is also working with Panasonic, Hisense, TCL, Changhong, and Skyworth on future TVs.

When Can I Get One, and What Will It Cost?

The new TVs showcased at CES each year usually start hitting stores in the spring, but some higher-end models don’t arrive until the fall. That’s a little bit of a wait, but it’s probably for the best—there are UltraHD content-delivery complications to work out, anyway.

The TV we know the most about in terms of pricing is TCL’s 55-inch H9700, and we still don’t know much. It’s already available in China for around $2,000 U.S., and TCL representatives at CES hinted that it will be close to that mark when it hits the U.S.

Expect that to be at the low end of the quantum-dot price bracket; LG, Samsung, and Sony generally have pricy TVs, and similar 4K LCDs from last year—minus the quantum dots—went in the $2,000 to $3,000 range for a 55-incher. For this initial wave of quantum-dot TVs, most MSRPs will probably fall between $2,500 to $4,000 for a 55-inch 4K set.

Quantum Dots Enter Mainstream Mobile Device Market

Last month, Amazon released Kindle Fire HDX 7 — the first ever mobile device to feature a quantum-dot-enhanced display.

The 7″ display includes a Quantum Dot Enhancement Film (QDEF) produced by 3M in collaboration with Nanosys, Inc. Compared to the traditional LED-LCD display, the QDEF essentially replaces the YAG phosphor of the white LED backlight and functions as a high-efficiency photoluminescent emitter. The ODEF includes quantum dots of different sizes, which would emit different colors when excited due to quantum confinement effect. More detail of the QDEF can be found via the link below.

http://www.nanosysinc.com/what-we-do/display-backlighting/qdef-how-does-it-work/

It is noted that the quantum-dot-enhanced display of Kindle Fire HDX 7 does not utilize the electroluminescent property of quantum dots, and thus is not actually a quantum dot light emitting diode (QLED). Nevertheless, it could signal the beginning of the mass commercialization of quantum dots technology in consumer markets.

And the very “best” of todays technologies? According to Displaymate, quote:

“The very best of today’s display technologies? The Quantum Dots displays used in the Kindle Fire HDX 7 according to the report.

Quantum Dots are almost magical because they use Quantum Physics to produce highly saturated primary colors for LCDs that are similar to those produced by OLED displays. They not only significantly increase the size of the Color Gamut by 40-50 percent but also improve the power efficiency by an additional 15-20 percent. Instead of using White LEDs (which have yellow phosphors) that produce a broad light spectrum that makes it hard to efficiently produce saturated colors, Quantum Dots directly convert the light from Blue LEDs into highly saturated primary colors for LCDs. You can see the remarkable difference in their light spectra in Figure 4. Quantum Dots are going to revolutionize LCDs for the next 5+ years.”

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How does QDEF work?

Nanosys QDEF™ enables deep color and high efficiency by providing displays with an ideal light source. How does it do that?

Each sheet of QDEF contains trillions of tiny (by tiny we mean: a bit bigger than a water molecule but smaller than a virus in size) nanoscrystal phosphors, called “Quantum Dots .” Not found naturally occurring anywhere on Earth, these “dots” can be tuned, by changing their size, to emit light at just the right wavelengths for our displays and do so very efficiently.

Unlike conventional phosphor technologies such as YAG that emit with a fixed spectrum, quantum dots can actually convert light to nearly any color in the visible spectrum. Pumped with a blue source, such as the GaN LED, they can be made to emit at any wavelength beyond the pump source wavelength with very high efficiency (over 90% quantum yield) and with very narrow spectral distribution (only 30 – 40nm FWHM.) The real magic of quantum dots is in the ability to tune the color output of the dots, by carefully controlling the size of the crystals as they are synthesized so that their spectral peak output can be controlled within 2 nanometers to nearly any visible wavelength.

For the first time, display designers will have the ability to tune and match the backlight spectrum to the color filters. This means displays that are brighter, more efficient, and produce truly vibrant colors.

How does it all come together?

Engineering the quantum dots to precise display industry specifications isn’t enough to revolutionize the way LCDs are experienced on its own. The dots need to be easily integrated into current manufacturing operations with minimal impact on display system design if they are to be widely adopted. To do this, Nanosys spent a lot of time working with major display manufacturers to get the packaging just right so that it would be a simple, drop-in product that did not require any line retooling or process changes. The end result is called Quantum Dot Enhancement Film or QDEF.

Designed as a replacement for the an existing film in LCD backlights called the diffuser, QDEF combines red and green emitting quantum dots in a thin, optically clear sheet that emits white light when stimulated by blue (some of that blue is allowed to pass through to make the B in RGB at the LCM of course). So manufacturers who’ve invested billions in plant and equipment for LCD production can simply slip this sheet into their process, change their ‘white’ LEDs to blue (the same LEDs but without the phosphor) and start producing LCD panels with the colors and efficiencies of the best OLEDs, at a fraction of the cost and current industrial scale.

Nanosys is currently shipping production samples to display manufacturers and is on track to begin producing at commercial volumes fall of 2013.

3M to Challenge OLED Displays with Quantum Dots

The giant industrial company says it will commercialize a quantum-dot optical film that dramatically improves LCD color.

OLED TVs: on sale soon 3M’s optical systems business division is to collaborate with the venture-backed company Nanosys on a new quantum-dot technology that promises to help conventional liquid crystal displays (LCDs) hold off the challenge of organic LEDs (OLEDs). OLED televisions will be launched this year by LG Display and, in all likelihood, Samsung, while other TV companies such as Panasonic and Sony are expected to follow suit. One of the big selling points of the technology is its more vibrant representation of colors, thanks to the fact that OLEDs are direct emitters of colored light – whereas LCDs are effectively filters of white light. In an announcement timed to coincide with the Society for Information Display (SID) 2012 “Display Week” meeting – traditionally the event where new display technologies are first reported – Nanosys and 3M said that they intend to commercialize what is known as “quantum dot enhancement film” (QDEF) technology. “QDEF is a drop-in film that LCD manufacturers can integrate with existing production processes,” say the two companies, meaning that the technology is directly compatible with existing LCD production – where 3M’s optical films already play a major role. “It utilizes the light-emitting properties of quantum dots to create an ideal backlight for LCDs.” Rather than actively creating light, the quantum dot films developed by Nanosys effectively work like a phosphor. When exposed to blue emission provided by a phosphor-less gallium nitride LED backlight, the dots produce narrow-linewidth red and green light, which can be combined with the original blue emission to generate a high-quality white backlight. Atomic behaviour Because they are so tiny, quantum dots behave in a similar manner to individual atoms, rather than bulk solids. And the precise color of the light that they produce when illuminated by blue LEDs is determined purely by their size. So by tightly controlling the size of the dots, they can be “tuned” to produce either red or green light at a precise and narrow range of wavelengths. In an LCD display, what that translates to is a white backlight with a much wider color “gamut”, meaning a much more life-like representation of images on the screen is possible. “Current LCDs are limited to displaying 35 percent or less of the visible color spectrum,” the companies say. “This means the viewing experience on an LCD is vastly different than what a person sees in the real world.” By increasing that color range by a claimed 50 percent, the QDEF technology offers a challenge to one of the key selling points associated with OLED displays – the vivid color reproduction that results from using direct light emitters in the pixels of the display. Jason Hartlove, the CEO of Nanosys, said: “We are working together to improve an area of display performance that has been largely neglected for the last decade. Improving color performance for LCDs with drop-in solutions will bring a stunning new visual experience to the consumer and a competitive advantage to the LCD manufacturer against new display technologies such as OLED.” SID “Gold” award for QDEF LED-backlit TVs and monitors are now commonplace, but one of the original commercial claims for using the technology was identical to that now being heralded by 3M and Nanosys – that it would improve color gamut dramatically, compared with the white fluorescent backlights that initially dominated in LCD TVs. As things turned out, it was not color gamut but the ability to make TVs much slimmer and lighter that propelled LED backlights into the mainstream, largely thanks to the intervention of Samsung. And as the world’s leading producer of active-matrix OLED screens – largely for its own mobile phone and tablet offerings – Samsung has a foot in both camps when it comes to improving color representation in the next generation of TV technologies. Interestingly, the Korean company’s venture wing – Samsung Venture Investment Corporation – led Nanosys’ series E round of financing, which raised $31 million in late 2010. The QDEF technology was also recognized at SID’s annual Display Industry Awards ceremony earlier this week, winning the SID Gold Award in the category of “display component of the year” at the Boston conference and show. According to 3M, the quantum-dot film being commercialized by the two firms will simply replace a similar film already found inside LCD backlights, and for display manufacturers would require no new equipment or process changes.

3M to challenge OLED displays with quantum dots

OLED TVs: on sale soon

3M’s optical systems business division is to collaborate with the venture-backed company Nanosys on a new quantum-dot technology that promises to help conventional liquid crystal displays (LCDs) hold off the challenge of organic LEDs (OLEDs).

OLED televisions will be launched this year by LG Display and, in all likelihood, Samsung, while other TV companies such as Panasonic and Sony are expected to follow suit. One of the big selling points of the technology is its more vibrant representation of colors, thanks to the fact that OLEDs are direct emitters of colored light – whereas LCDs are effectively filters of white light.

In an announcement timed to coincide with the Society for Information Display (SID) 2012 “Display Week” meeting – traditionally the event where new display technologies are first reported – Nanosys and 3M said that they intend to commercialize what is known as “quantum dot enhancement film” (QDEF) technology.

“QDEF is a drop-in film that LCD manufacturers can integrate with existing production processes,” say the two companies, meaning that the technology is directly compatible with existing LCD production – where 3M’s optical films already play a major role. “It utilizes the light-emitting properties of quantum dots to create an ideal backlight for LCDs.”

Rather than actively creating light, the quantum dot films developed by Nanosys effectively work like a phosphor. When exposed to blue emission provided by a phosphor-less gallium nitride LED backlight, the dots produce narrow-linewidth red and green light, which can be combined with the original blue emission to generate a high-quality white backlight.

Atomic behaviour Because they are so tiny, quantum dots behave in a similar manner to individual atoms, rather than bulk solids. And the precise color of the light that they produce when illuminated by blue LEDs is determined purely by their size. So by tightly controlling the size of the dots, they can be “tuned” to produce either red or green light at a precise and narrow range of wavelengths.

In an LCD display, what that translates to is a white backlight with a much wider color “gamut”, meaning a much more life-like representation of images on the screen is possible. “Current LCDs are limited to displaying 35 percent or less of the visible color spectrum,” the companies say. “This means the viewing experience on an LCD is vastly different than what a person sees in the real world.”

By increasing that color range by a claimed 50 percent, the QDEF technology offers a challenge to one of the key selling points associated with OLED displays – the vivid color reproduction that results from using direct light emitters in the pixels of the display.

Jason Hartlove, the CEO of Nanosys, said: “We are working together to improve an area of display performance that has been largely neglected for the last decade. Improving color performance for LCDs with drop-in solutions will bring a stunning new visual experience to the consumer and a competitive advantage to the LCD manufacturer against new display technologies such as OLED.”

SID “Gold” award for QDEF LED-backlit TVs and monitors are now commonplace, but one of the original commercial claims for using the technology was identical to that now being heralded by 3M and Nanosys – that it would improve color gamut dramatically, compared with the white fluorescent backlights that initially dominated in LCD TVs.

As things turned out, it was not color gamut but the ability to make TVs much slimmer and lighter that propelled LED backlights into the mainstream, largely thanks to the intervention of Samsung.

And as the world’s leading producer of active-matrix OLED screens – largely for its own mobile phone and tablet offerings – Samsung has a foot in both camps when it comes to improving color representation in the next generation of TV technologies.

Interestingly, the Korean company’s venture wing – Samsung Venture Investment Corporation – led Nanosys’ series E round of financing, which raised $31 million in late 2010.

The QDEF technology was also recognized at SID’s annual Display Industry Awards ceremony earlier this week, winning the SID Gold Award in the category of “display component of the year” at the Boston conference and show.

According to 3M, the quantum-dot film being commercialized by the two firms will simply replace a similar film already found inside LCD backlights, and for display manufacturers would require no new equipment or process changes.

Nanosys Closes Sixth Funding Round: $15M New Investment to expand quantum dot manufacturing

 Palo Alto, Calif., November 26, 2012 – Nanosys Inc., an advanced materials architect, today closed a $15 million sixth round of funding. The company will use the new investment to expand its quantum dot manufacturing capabilities. Nanosys’ flagship quantum dot product is Quantum Dot Enhancement Film™ (QDEF), which vastly improves the color performance and efficiency of Liquid Crystal Displays (LCDs).

“You’ve never seen anything like a quantum dot display,” said Jason Hartlove, President and CEO of Nanosys. “We are working with display makers to create a new high color gamut display experience that is cheaper, more efficient and more reliable than anything else currently on the market. The response from manufacturers so far has been great and demand for QDEF has grown to the point that we’ll need to expand manufacturing to keep up.”

Nanosys will expand its quantum dot manufacturing line more than tenfold in order to meet increasing demand. The expansion will make Nanosys the largest quantum dot manufacturer in the world.

Most current LCDs are only capable of displaying 35 percent or less of the visible color spectrum. This means the viewing experience on an LCD is limited and vastly different from what is seen in the real world, as colors are altered or left out altogether. Wide color gamut displays make the viewing experience on an electronic device much closer to the vibrant visual experience of real life. An LCD powered by QDEF can display 50 percent or more color than a standard LCD. QDEF also provides a significant energy efficiency advantage over other LCD backlight technologies.

QDEF utilizes the light emitting properties of quantum dots to create an ideal backlight for LCDs, which is one of the most critical factors in the color and efficiency performance of the display. A quantum dot, which is 10,000 times narrower than a human hair, can be engineered to emit light at very precise wavelengths. QDEF relies on this unique ability to control the spectral output of a quantum dot to create an ideal white backlight specifically designed for LCDs. Trillions of custom engineered quantum dots are loaded into each sheet of QDEF, which fits inside an LCD backlight unit. The new film replaces one already found inside the LCD backlight, which means the manufacturing process requires no new equipment or process changes for the LCD manufacturer.

Nanosys Contact:
Daniel Klempay
(650) 762-2948
Dan.klempay@edelman.com

About Nanosys, Inc.
Nanosys, Inc. is an advanced material architect, harnessing the fundamental properties of inorganic materials into process ready systems that can integrate into existing manufacturing to produce vastly superior products in lighting, electronic displays and energy storage. For more information, visitwww.nanosysinc.com.