Quantum Dots Poised to Make IMPACT on LED Back-Lit LCD’s

What technology is in YOUR TV (Display) Screen?!

Ken Marrin, LED Magazine

Quantum dot (QD) technology has promised to enhance LED usage, making LCD TV images more vivid and improving efficacy in warm-CCT, high-CRI solid-state lighting (SSL). Thus far, however, cost, reliability, and lifetime issues have prevented broad commercial deployment. But the technology has progressed to the point that the TV application, with relatively shorter usage hours compared to general lighting, can adopt the technology.

Due to their high resolution, low cost, and thin form-factors, LED-backlit LCDs have become the standard for mobile devices and TVs, although color performance has lagged. (For more details on how LCDs and backlights work, see sidebar at end.) Displays on popular backlit LCD tablets can only express about 20% of the color a human eye can see, while LCD HDTVs can express only about 35%. To achieve more vivid, realistic color, display manufacturers have developed a variety of new technologies such as discrete RGB LED backlights, yttrium aluminum garnet (YAG) enhanced with red phosphor, and organic LEDs (OLEDs). All are beset with cost, scalability, and durability issues that have hampered widespread deployment.

FIG. 1.

One of the most promising new color enhancement technologies for backlit LCDs is QDs, a nanocrystal material that can be tuned to emit an optimized narrow spectrum of light. The unique semiconductor and optical properties of quantum dots make them attractive for a broad range of applications, from SSL, silicon photovoltaic cells, and quantum computing to cellular imaging and organic dye replacement. Due to the high production volumes and ease of integration with existing manufacturing processes, LCD suppliers seem to have taken a particular interest in QDs. By augmenting their backlight units (BLUs) with QDs, LCD manufacturers are able to create vivid displays that can exceed 55% of the spectrum a human eye can detect.

Why quantum dots?

Where vivid color and high efficiency are the objectives, the ideal white light is one that can be tuned to generate lots of visible energy narrowly focused on the primary red, green, and blue wavelengths used by the subpixel filters while producing very little light between. QDs do just that. The tiny nanocrystals, smaller than a virus, emit narrowband light when excited by a photon source.

Unlike conventional phosphor technologies like YAG, which emit with a fixed spectrum, QDs can be fabricated to convert light to nearly any color in the visible spectrum by simply varying the size of the dots. Size and bandgap energy are inversely related, so as the size of the QD decreases, emission frequencies increase, resulting in a color shift from red (low energy) to blue (high energy) in the light emitted. Lifetime fluorescence is also determined by the size of the QD, with larger dots showing a longer lifetime.

By carefully controlling the size of the crystals as they are synthesized, the spectral peak output can be set to within 2 nm of nearly any visible wavelength. Such control enables QDs to be tuned so the backlight spectrum matches the color filters, thereby facilitating displays that are brighter and more efficient, and produce truly vibrant colors.

Integrating QDs with the BLU

Quantum dot approaches are similar to phosphor technologies in the way they attempt to engineer the white light spectrum. As with YAG, a blue GaN LED provides the source light. QDs then downconvert a portion of the blue light into narrowband red and green spectrum, thereby achieving a white light that is rich in red, green, and blue and matched to the subpixel filters. QDs can be tuned (by varying the size) to emit at any wavelength longer than the source wavelength with very high efficiency (over 90% quantum yield under ideal conditions) and with very narrow spectral distribution — just 30–40 nm full width at half maximum (FWHM). This high spectral efficiency in turn reduces display power consumption by 20% compared to other high-gamut color-enhancement techniques — a key factor in meeting Energy Star requirements in TVs or extending battery life in portable devices where displays often consume 40% of the power.

As with YAG, QD backlight technology is easy to integrate with existing LCD manufacturing processes. QD upgrades require no line retooling or process changes. So manufacturers who have invested billions in LCD plants and equipment can quickly deploy QD-enhanced LCD panels that offer the color and efficiency of the best OLEDs at a fraction of the cost.

FIG. 2.

3M, for example, is now using QDs supplied by Nanosys, Inc. to offer a quantum-dot enhancement film (QDEF) a thin, optically-clear sheet with red and green dots that replaces the existing diffuser film in the reflective cavity of an LCD backlight. This packaging, explains 3M marketing development manager Art Lathrop, “not only simplifies integration and protects the dots against flux but boosts efficiency by recycling light emitted in the wrong direction.”

3M has initially focused on mobile displays where the industry has put more emphasis on premium quality and displays sell for a relatively high price per square meter. Larger displays are not only more price sensitive, Lathrop added, but also heavier users of QDs in the film implementation. When an application grows linearly (long strips of displays, for example), the QD film and the number of dots used in the film grows linearly as well, so cost is not a problem. However, when the application grows more by area than length — as in a TV display — then the number of QDs required for the film grows exponentially with display size, and the cost of QDs becomes a significant factor. Lathrop expects this issue to abate as the raw QD materials get cheaper and packaging/manufacturing (inexpensive film vs. glass, for instance) becomes the driver of overall QD cost. Until then, 3M will focus on smaller displays with lower raw material costs such as consumer mobile devices.

Drop-in QD technology

QD Vision also provides a drop-in technology called Color IQ, though instead of packaging the QDs as a film, QD Vision employs a glass tube that mounts on the edge of the display (Fig. 1). Unlike the 3M film, which scales geometrically, the rail solution scales linearly, making it more effective for larger displays. “With an edge solution like Color IQ,” said QD Vision CTO Seth Coe-Sullivan, “we utilize about one-hundredth of the QD materials relative to a film solution of the same screen area. This is why you see 3M launching in the Kindle with a screen area of one-sixtieth of a square meter, while we are in big-screen Sony TVs.”

Nanosys CEO Jason Hartlove concedes that the film solution is a heavier dot user but puts the differential at about 5x. The shorter optical path in the edge solution, he argues, requires a much higher dot density (less opportunity for recycling) and is also susceptible to aggregation and quenching, which reduces the dot’s light output and requires additional LEDs to get the same brightness.

FIG. 3.

Pacific Light Technologies got its start in nanotechnology developing QDs for the solar industry, where the dots are used to convert solar energy into a low-energy format that can be utilized more efficiently by solar panels. From there, the company branched off into SSL, using QDs to create warmer lighting solutions. More recently, the company has attracted interest from display makers. Their key differentiator, according to vice president of marketing Julian Osinski, is the ability to fabricate dots directly onto blue LEDs, eliminating the need for a separate QD subassembly (Fig. 2). “A display requiring coverage over the full surface can be on the order of 10,000x the surface area of the LED chips used to illuminate the display,” said Osinski, “and since the amount of QDs required scales with surface area, that means 10,000 times less QD material is required for on-chip use compared to off-chip.”

Pacific Light uses the same process for adding dots to LEDs that manufacturers use to add phosphor. The QDs are synthesized in a reactor vessel, separated out, mixed into a silicone, and then applied to the chip. “One nice advantage,” noted Osinski, “is that unlike phosphors, there is no settling of QD particles, resulting in more stable color points during manufacturing.” Pacific Light Technologies is currently shipping red dots, with plans for green dots in the future.

Quantum dot reliability

The useful life of the QDs is a complex issue heavily dependent on the application and the operating conditions. Fundamentally, what kills dots the fastest is oxidation. Beyond that, assuming that the dots are very well protected from oxygen, they also deteriorate from being used (like most emitters), and that deterioration accelerates with elevated heat and flux, particularly flux. Temperature at the film is about 40°C vs. 90°C at the edge, and 140°C at the LED, said Hartlove of Nanosys. Flux is 25 MW/cm at the film, 1–10W/cm at the edge, and from tens to hundreds of watts per centimeter at the LED — five orders of magnitude from the film to the LED.

3M’s testing, said Lathrop, shows that in most consumer applications QDEFs last for 20,000 to 30,000 hours of operation before luminance drops by 15%. A larger drop will start to result in a noticeable color shift (blue is not impacted). 3M’s next-generation product is targeting twice that lifetime, not because display makers are looking for 60,000+ hours but because they want to use them in hotter displays (all-in-one PCs or specialty displays, for example).

QD Vision’s edge solution, which encapsulates the dots in a glass tube, provides an excellent barrier to oxygen, as well as other advantages such as lower volume utilization, low-tech barrier materials, and excellent color uniformity (no blue light leakage). “Our edge implementation also presents unique challenges,” explained Coe-Sullivan. Color IQ sits closer to the LED backlight than a film, so the dots must withstand higher heat (100°C) and flux (100x that of a film). Nonetheless, Coe-Sullivan claims to have overcome those challenges and rates the Color IQ lifetime at between 30,000–50,000 hours, essentially the same as present-day LEDs.

FIG. 4.

Pacific Light Technologies’ approach to mounting dots directly on the LED may offer the most significant potential cost and performance advantages of all (Fig. 3) but also the greatest challenges with regard to reliability. In addition to higher temperatures, flux in particular can be 50x that of an edge solution. “In general,” noted Osinski, “white-light LED lifetimes are limited by the silicon-phosphor combination on the chip more than the chip itself, and that remains the same with QDs, where silicone yellowing also contributes to aging blue LEDs.” Reliabilities are still being established because they require very long test times, but Pacific Light claims to have already demonstrated operation over thousands of hours.

OLED

One of the chief competitive technologies to QDs where color quality is of primary importance is OLED, which emits light directly and requires no backlight or LCD filter. In addition to excellent color gamut comparable to QDs, OLED displays feature faster response times and refresh rates, improved brightness, a greater contrast ratio (both dynamic range and static, measured in purely dark conditions), a wider viewing angle than LCD implementations (with or without QD augmentation), and the ability to display true blacks.

Perhaps the biggest technical problem for OLEDs is the limited lifetime of the organic materials, primarily for the blue OLEDs. Blue OLEDs historically have had a lifetime of around 14,000 hours to half original brightness (five years at 8 hours a day) when used for flat-panel displays. Red and green OLEDs offer 2–3x that lifetime. The faster degradation of blue OLEDs relative to red and green creates color balance challenges, requiring either additional control circuitry, or optimization of the red, green, and blue subpixel sizes in order to equalize color balance at full luminance over the lifetime of the display. A blue subpixel, for example, may need to be 100% larger than the green subpixel, whereas the red subpixel may need to be 10% smaller than the green.

High cost has also hampered the widespread use of OLEDs in larger mass-market displays. Eliminating the backlight and LCD filter provides significant cost savings and allows for a thinner display, but the fabrication of the OLED substrate is presently more costly than that of a thin-film transistor LCD. Down the road, the ability to fabricate OLEDs on flexible plastic substrates and the utilization of processes like roll-to-roll vapor-deposition and transfer printing will offer potential cost advantages. For now, though, large-screen applications require low-temperature polysilicon backplanes that cannot currently be used on large-area glass substrates. As a result, large OLED displays are limited to relatively high-end applications, with OLED TVs from LG and Samsung selling in the $10,000 range. On the other hand, Sony uses QD Vision’s technology, branding it Triluminos, in its 4000-pixel Ultra HD LCD TVs that start at about $3500 (Fig. 4). But Sony has also included Triluminos technology in some higher-end standard HDTV sets such as a 55-in. model that sells for around $2000.

Electroluminescent QDs

Even as OLED strives for economies of scale and process improvements that will bring costs down, QD makers like QD Vision are already working on the next generation of technology — electroluminescent QDs that will combine the customizable, saturated, stable color and low-voltage performance of inorganic LEDs with the solution processability of polymers. The new technology, Coe-Sullivan explains, will provide a reliable, energy-efficient, highly tunable color solution for displays and lighting that is less costly to manufacture and that can employ ultrathin, transparent, or flexible substrates.

Quantum-dot light-emitting diodes (QLEDs) are electroluminescent colloidal quantum dots that generate light when excited electrically. Like OLEDs, QLEDs require no backlight or LCD filter. QD Vision claims that its printable thin-film QLEDs match or exceed NSTC color standards for displays without the need for color filters. The excellent color performance of QLEDs ultimately translates into a 30–40% luminance efficiency advantage over OLEDs (at the same color point), which require lossy color filtering to achieve a similar color performance. QLEDs also feature a lower operating voltage, exhibiting turn-on voltages at the bandgap voltage of the material. This gives QLEDs the potential to be more than twice as power efficient as OLEDs at the same color purity.

To reduce cost for QLED-based, full-color, active-matrix displays and lighting devices, QD Vision is developing large-area quantum-dot printing techniques that utilize ultrathin flexible substrates. Today’s LCDs and LED chips are fabricated on glass and crystalline substrates, making them inherently expensive and fragile for mobile and large-area applications. QLEDs, by contrast, are only a couple hundred nanometers thick, making them virtually transparent and flexible, and highly suitable for integration onto plastic or metal foil substrates as well as other surfaces.

QLEDs are still in the early development stages, yielding only 10,000 hours at low brightness, but in theory are a more stable light-emitting material than organic dyes. Meanwhile, the company is already offering high-quality electroluminescent-grade QD materials suitable for certain products that require precise color solutions in an ultraslim form factor. Among these are monochrome visible and infrared displays, and lighting devices for machine and night vision applications.

Nanosys’ Hartlove agreed that the QLEDs are the way of the future. “When emissive pixels will overtake LCDs we cannot say. LCDs get better every day.” Within ten years, however, he expects the manufacturing and production advantages of QLEDs (solution chemistry and roll-printed emitters) to overtake GaN substrates and wafer-based processing — and not just for displays but also general lighting. Right now, the focus is on the ability of QDs to outperform phosphors in the color arena, but eventually the properties of the raw materials will fade in significance, and it will come down to manufacturing, where the ability to print narrowband emissive pixels on thin films in high volume will produce high-quality color inexpensively — without the need for color management.

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Backlight enhancement

Liquid-crystal displays (LCDs) combine a light source (the backlight unit, or BLU) with a liquid-crystal module (LCM). The BLU provides a uniform white sheet of light behind the LCM. The LCM contains millions of pixels, each of which is split into red, green, and blue subpixels. By controlling the amount of time each subpixel filter is open (allowing light to pass through it) and making use of the human eye’s persistence of vision, the LCD can display any color that can be rendered from a combination of red, green, and blue at each pixel location. The color filter on each subpixel separates its component color from the white light of the BLU. For example, the red color filter on the red subpixels blocks the green and blue light.

The fidelity of each color is a function of the quality of light in the BLU and the color filters. The narrower the filters, the narrower the backlight color spectrum (for the desired peak red, blue, and green colors), and the closer the color spectrum is matched to the filters, the higher the color quality. Because making perfect color filters is impractical from a cost and brightness perspective (narrow filters attenuate out-of-band photons and reduce brightness), display makers have instead focused their efforts on improving the BLU.

The problem with standard BLUs is that the LEDs used to create the backlight produce a broad spectrum of light that cannot be used efficiently by the LCD. Most white LEDs are created by coating blue LEDs made of indium gallium nitride (InGaN) with an yttrium aluminum garnet (YAG) phosphor. These two-color YAG white LEDs produce a spectrum rich in blue wavelengths with a broad yellow component, but the greens vary from cyan through lime, and the reds vary from orange to deep red. Because the filters can’t stop these in-between colors, the result is poor color saturation.

Red-emitting phosphor can be added to boost color performance, but red phosphors suffer from poor conversion efficiency, wasting much of their power-generating spectrum like infrared that is not visible to the human eye. Like the yellow phosphors, red phosphors have a relatively wide full width at half maximum (FWHM) — a characterization of the width of the spectrum at which emitted radiometric power has dropped by half — so they cannot be precisely tuned to match either existing color filters or the manufacturers’ peak color specifications. So the resulting white light, while offering a richer spectrum, still incurs substantial light and efficiency losses

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.

Quantum Dot Markets: Emerging Commercial Technologies

Published: August 14, 2013 Category: Advanced Materials Emerging Electronics

 

 

NanoMarkets believes that Quantum Dots (QDs) have good potential to be a dominant large display format technology in the near term, but will take some more time to find commercial applications in the small display segment. In addition, NanoMarkets believes that in the near to mid-term, the lighting industry is likely to witness a good number of commercial launches, particularly in the solid-state lighting (SSL) segment, in which QDs have the potential to replace LED phosphor-based lighting solutions.

Downstream suppliers of QD raw materials are likely to expand their manufacturing facilities in order to meet the growing demand for QDs from consumer electronics producers, particularly TV manufacturers, as well as research facilities and some SSL-based lighting solution providers.

The QD market can be broadly classified into two segments:

• Displays employing QD technology in large (TVs) and small formats (smartphones, tablets, etc.) Although QD-based TVs have begun to emerge commercially, it will take some time for the market to realize their full potential. Meanwhile, small display formats are likely to test the commercial viability of QD-based solutions in their commercial products.

• Solid-state lighting solutions, where QDs have begun to find applicability in personal electronic devices, such as smartphones and tablets, and exterior signage. However, certain pitfalls with regard to tuning the color range, producing a true white color, and high costs have limited the application of QDs in home and commercial lighting setups.

NanoMarkets expects the U.S. to be at the forefront of QD-related research activities, as evident from the presence of a wide network of QD research-based start-ups and the number of collaborative deals that some of these start-ups have struck with established raw materials suppliers and OEMs, particularly in the consumer electronic display segment.

QD TVs Emerge, While QD-Based Smartphones and Laptops Have Yet to Gain Commercial Acceptance

Large display segment: QD-based solutions have made significant inroads in large format displays such as TVs, primarily because of the versatile applicability of QDs in a wide range of display devices combined with their better color production, color purity, and power efficiency.

Large format QD-based display solutions are mostly licensed to OEMs by a few innovative start-ups, such as QD Vision, Nanosys, Nano Photonica, and Nanoco Group.

An early entrant, QD Vision, is likely to lead the market. The company has strong collaborations with several leading TV manufacturers. Two of its patented technologies hold significant potential:

• Using currently available QD technology for displays that require a backlight source, Sony has incorporated QD Vision’s proprietary Color IQ technology in its 55-inch Triluminous brand of LCD TVs.  These QDs emit pure green and pure red light and have superior color reproduction capabilities compared to those found in most commercially available TVs.

• A quantum dot light emitting diode (QLED) is a direct-emissive display technology that is likely to do away with the requirement for an underlying substrate and backlight source. The technology is currently on the verge of commercialization and is likely to find application in next-generation electronic displays because of its proven superiority to organic light emitting diodes (OLEDs) in terms of reduced manufacturing costs, better power efficiency, and the ability to emit pure colors.

In addition to Sony, other notable consumer electronics players that are vying for a sizable share of the large format QD display segment include:

• Samsung, which is currently working in collaboration with Nano Photonica to incorporate the latter’s proprietary S-QLED technology, which seems to promise low cost and versatility across all display sizes, into TVs that should reach the market in late 2014 or early 2015.

• LG, which has also been working with multiple entities that have patented QD technologies, such as Nanosys and QD Vision; however, there are uncertainties regarding the timeframe for commercial launch of any QD-based products.

• Sharp, which has reportedly been working on QD technology; however, nothing concrete has been officially confirmed by the company. It is a general concern among manufacturers to alter existing processes in order to accommodate commercial production of any product based on a new technology.

The same applies to the adoption of QD technology. In order to address such manufacturing concerns, Nanosys, in collaboration with 3M’s Optical Systems Division, has developed proprietary Quantum Dot Enhancement Film (QDEF) technology that is designed to replace the traditional LCD backlighting unit. This technology therefore offers TV manufactures a readymade solution for incorporating QDs into their existing manufacturing facilities with minimal incremental cost.

Despite rumors of a significant extended product development time, 3M has indicated that it expects to commercially roll out the QDEF-based solutions for OEMs offering TVs, smartphones, and tablets by the end of 2013. Due to the adaptive nature of the technology within the existing LCD manufacturing framework, QDEF could potentially replace other competing phosphor-based technologies and OLEDs in the next generation of TVs.

Small display segment: The flexibility and high energy efficiency of ultra-thin film QDs make these nanomaterials potentially valuable for small displays. However, despite this strong potential (including that of technologies such as QDEF (patented by Nanosys)), only a few commercial QD-based products have been developed for this segment. Some of the barriers to entry to this segment, which limit the participation in this industry, include the dominance of OLED technology in the market, the longer time required for commercialization of these products, and lack of initiatives to set up large-scale manufacturing facilities.

A few notable players pursuing the small display strategy include:

• Osram, which is one of the few suppliers of QD backlighting solutions (through its MicroSideled brand) that offer minimal color loss and high power efficiency for personal electronic devices, such as tablets, ultra-books, and smartphones.

• Sony, which is one of the few electronic OEMs that currently offers its proprietary QD-based display (Triluminous) in its Xperia range of smartphones and Vaio range of laptops. The entry of established players in the small display segment will likely spur additional research efforts and increase the scope of possible commercial launches.

 

Key concerns in the display industry: QDs are likely to face stiff competition from OLEDs, a technology in which some of the leading OEMs, such as Samsung, have already invested heavily. It is expected that Samsung and other OEMs will require some time to recoup their investments before shifting to a new technology such as QDs.

Some of the key business concerns in the display industry regarding QD-based solutions are:

• The role of start-ups and their IP positions,

• The race among OEMs to secure licensing deals, and

• The verified performance improvements that QDs provide compared to OLEDs.

The QD supplier community is typically comprised of technology start-ups with IP rights that either license their products to OEMs or directly sell to research facilities. Consumer electronics OEMs are likely to generate the maximum demand for QDs in the coming years. Thus, it makes sense for QD providers holding IP positions to work in collaboration with established raw material suppliers to the electronic display industry or directly with the OEMs, which typically have large distribution networks and marketing prowess.

Clearly, companies that hold IP positions in QD materials are likely to depend heavily on OEMs and other big raw material suppliers to gain market visibility.

However, firms such as QD Vision and Nanosys will have a significant advantage over other players because of their innovative product lines, which are flexible enough to serve different display segments. Moreover, with the commercial success of QD technology, established electronic display manufacturers are likely to select such strong suppliers in order to secure their QD raw material base. OEMs will, in fact, compete with one another to strike exclusive deals with leading QD material suppliers. Although product profiles are likely to expand over time, the competitive pressure will lead to some level of consolidation, with only the financially strong players emerging as successful suppliers of QD materials to the display industry.

While compared to OLEDS, QDs offer the manufacturing advantage of fitting into the existing backlighting units of LCD TVs; QDs must also offer dramatic performance enhancements over OLEDs in order to attract investment. Long product lifetimes and cost-effective large-scale manufacturing are likely the key factors that will make QD technology successful in the display industry in the near future.

Future outlook for the display industry: In the next two-three years, QDs are likely to dominate the LCD backlighting TV segment, while it will take four-five years to witness the commercial entry of large display products based on direct-emissive (pure QD) technologies, such as the QLED technology developed by QD Vision, that can be applied across a wide range of display formats, including ultra-thin products.

Although OLEDs are to some extent comparable to QDs in terms of their versatility, smart customization moves from QD material suppliers, such as those made by Nanosys with its QDEF technology, have the potential to place QDs at the forefront of next-generation large display products that are likely to hit the market in the mid-term. Moreover, the intent of big raw material suppliers, such as Dow Electronic Materials (DEM) and 3M, to serve the display segment with QD products in a big way should be considered a positive move by other OEMs and suppliers.

Other players are likely to follow suit, given the likely commercial launch of QD-based solutions from DEM (in collaboration with Nanoco Group) in the first half of 2014 and 3M (in collaboration with Nanosys) by the end of 2013. NanoMarkets believes that the large display manufacturers, such as Sony and Samsung, will play a significant role in the commercialization of QD products, although they are likely to make smaller investments in the QD space compared to those made in OLED technology.

Even so, NanoMarkets expects that commercialization in the large display segment will progress at a faster rate than that in the small display segment, in which manufacturers are likely to carefully gauge the market potential of QDs and follow policies similar to those adopted by the established players, such as Sony and Samsung.

QD-Based Solid State Lighting on the Verge of Commercialization, but Little Impact in Other Lighting Categories Solid-state lighting (SSL) segment:

In the solid-state lighting (SSL) segment, QLEDs hold significant promise in terms of commercial success, because QLED-based lighting solutions can be applied on flexible surfaces and offer better efficiency, a wider color range, and better color saturation than other competitive products, such as LED phosphors. In addition, the high costs associated with OLED manufacturing have kept this technology out of the reach of residential and commercial consumers, a fact that can actually play in favor of QLEDs in the near future.

Energy-saving cost benefits, low toxicity, and the ability to provide true incandescent light make QD-based SSLs a strong contender for new SSL solutions and potential replacements for existing LED phosphor-based SSLs.

As in the display segment, QD Vision has a significant first-mover advantage in the SSL segment. As early as 2009, the company demonstrated its patented ‘Quantum Light’ QD–based SSL technology in collaboration with Nexxus Lighting Inc., which incorporated the technology in its commercially available ‘Array’ series of lamps. QD Vision’s ‘Quantum Light’ technology, which offers better energy savings and a longer shelf-life than conventional halogen lamps, is ideal for downlight solutions typically used in commercial and residential settings.

While QD Vision heads the pack of QD solution providers, there are others that are likely to make their presence felt in the SSL domain with proprietary QD-based solutions:

• Using NN Crystal’s proprietary QShift Coral technology, Renaissance Lighting has commercially launched downlight solutions that can be precisely controlled to emit pure light of a particular color.

• Pacific Light Technologies, which is solely focused on developing toxic material-free QDs for the SSL industry, is likely to attract consumer attention once it is commercially launched.

• Wisys Technology Foundation, working in collaboration with the University of Wisconsin, has also developed a proprietary QD-based SSL solution that is ready for market testing. These early advances should ideally incentivize other developers of QD-based SSL solutions to push their products from the research lab into consumers’ hands.

An increase in the number of QD-based offerings is critical for the success of the technology in the lighting sector, given that currently there are only a handful of organizations offering commercially available QD-based SSL products. It must be noted, however, that successful commercial launches of QD-based lighting solutions also depend heavily on the extent of the financial support received by the research organizations developing QD-based solutions.

Recognizing this fact, the U.S. government, through the Department of Energy (DOE), is providing financial grants to QD-based projects in order to move laboratory products to the commercial launch stage.

Some grant receivers include:

• The University of Buffalo, which is developing high-efficiency colloidal QD phosphors, and

• The University of California, which is developing QD phosphors for SSL applications.

Other lighting segments:

QD technology also has significant advantages over currently available LCD and OLED technologies in terms of better image performance and power efficiency in applications such as projectors, video walls, and digital signage. Trenton Systems is one firm that sees potential for QDs in such applications. The company is planning for the possible introduction of a QD-based video wall.

However, there are uncertainties with respect to the adoption rate of QD technology in these niche lighting segments, primarily due to the high product costs and the need to change existing manufacturing processes.

 

Key concerns in the lighting industry:

Although some QD material suppliers have achieved a head start in the SSL segment, there are reasons why a majority of the QD-based research activities have shied away from this segment.

The display industry has two key concerns about QD-based solutions:

• The expensive manufacturing processes for commercial products and

• The attractiveness of the business segment.

Commercial manufacturing processes for QD-based solid-state lighting solutions remain expensive and it will be some time before economies of scale can be achieved. This should prompt the development of cost-effective techniques for manufacturing general purpose lighting products.

In addition, the incremental performance benefits that QDs provide compared to conventional lighting solutions, such as CFLs and LEDs, will also be important factors deterring the rate of adoption of QDs by the lighting industry at large.

The competition for research dollars with other segments, particularly the lucrative display industry, is another major factor affecting the development of QD-based lighting solutions.

Hence, a successful foray into SSL and other residential and commercial lighting solutions will depend significantly on several key factors, including the development of cost-effective mass production capabilities and favorable government mandates for the adoption of energy efficient measures, such as the U.S. government’s emphasis on replacing 100 watt and 75 watt incandescent bulbs with 60 watt and 40 watt bulbs.

 

Future outlook for the lighting industry:

NanoMarkets believes that, in the lighting segment, SSL is likely to provide the maximum number of innovative opportunities for start-ups such as QD Vision and other QD materials producers.

It will be necessary, however, for major lighting industry OEMs to make such products commercially available. NanoMarkets is also of the opinion that some of the U.S. government-assisted QD-based SSL research projects are likely to gain commercial significance in the near to mid-term; however, other lighting segments are likely to wait and watch for radical innovations that will offer potential manufacturers a viable route to break into commercial markets.

At the same time, NanoMarkets thinks that QD materials firms should also look beyond traditional business segments and target niche lighting categories, such as projectors, video walls, and digital signage – business segments in which QD solutions can address the significant issue of high energy consumption.

QD Material Suppliers Likely to Benefit in the Mid-Term QD materials form the fundamental building blocks of any QD device.

These materials primarily consist of either heavy metal (HM)-based semiconductor materials or non-heavy metal (NHM)-based semiconductor materials. Typically, NHM-based QDs find use in biomedical applications, while HM-based QDs have been traditionally used in all other applications. However, growing concerns over the use of cadmium have led researchers to shift their focus on NHM-based QDs.

HM-based QD materials: QDs have been traditionally based on HM semiconductor materials, such as cadmium telluride, zinc sulfide, lead selenide, and zinc cadmium selenide. The supplier base remains fragmented, with OEMs having the option to choose from several patented QD materials.

The success of material suppliers is likely to be determined by their ability to mass produce QDs of consistently high quality.

Therefore, traditional suppliers, such as American Elements and M K Impex Corporation, will need to not only continue to differentiate themselves on the basis of their product variety, but also look to acquire mass production capabilities.

NanoMarkets believes that companies such as Nanoco Group and Quantum Materials Corporation, which hold IP positions related to QD materials and novel large-scale QD manufacturing techniques, are likely to have an edge over others because they will be in a position to strike bulk HM-based QD manufacturing deals with OEMs in the near to mid-term.

 NHM-based QD materials: Addressing growing environmental concerns over the use of certain heavy metals, such as cadmium and lead, has led to the emergence of NHM-based QDs. NHM-based products have begun to emerge only recently, however, and the supplier base with large-scale production capabilities is limited at this time. Some of the companies with patented mass production manufacturing techniques include:

• U.K.-based Nanoco Corporation, which has modified its existing HM-based QD manufacturing techniques in order to produce NHM-based QDs with optical properties identical to the well-accepted properties of HM-based QDs. Nanoco has patented this mass production technique in order to cater to the growing demands of the electronic display industry.

• U.S.-based Quantum Materials Corporation, which by the end of 2013 will be mass producing an entire range of HM-based and NHM-based quantum dots using its patented continuous flow process. The company’s range of QD materials is likely to find applicability in various industries including display and lighting, but the firm’s focus has been on developing QD materials suited for the biomedical and solar energy segments. NanoMarkets believes that QD material providers in this highly specialized material segment are likely to ensure business viability through continuous IP-related research activities, which will enable these manufacturers to receive a steady stream of licensing revenues from OEMs in the mid-term.

However, NanoMarkets expects significant development efforts will also be directed towards the implementation of cost-effective large-scale manufacturing techniques, which will be the key to the commercialization of cost-effective and high-performance QDs.

Technology Gaps in Current-Generation QD Materials It must be noted that despite their proven potential, QDs have yet to become the material of choice for the display and lighting industries.

Although this trend can be partly explained by the fact that OEMs are hesitant to dramatically shift towards a new technology such as QDs before recouping their investments in other similar and promising technologies (OLEDs), there are also several technological barriers that QDs must overcome in order to prove their superiority over other rival technologies.

Some of the current material-related issues faced by QDs include:

• The suitability of current fabrication techniques to facilitate cost-effective mass production;

• The ease of manufacturing blue QDs; and

• Blinking issues with QDs.

Despite the emergence of several fabrication techniques for the effective manufacture of QDs, the majority of currently available fabrication techniques do not provide significant room for cost reduction in large-scale production.

Research efforts to develop new fabrication techniques or modify existing techniques are highly desired. Until a cost-effective fabrication technique is developed, QDs may not be able to make the leap to commercial success.

With respect to display solutions, the majority of current-generation QDs is likely to find initial applicability in the LED backlighting space. However, the difficulty in producing blue QDs on a consistent basis is a major cause of concern for LED and LCD TV manufacturers.

In addition, because blue QDs are likely to be smaller than red QDs, blue and green variants of blue QDs require manufacturing techniques that make them visible to the human eye. Thus, QD materials manufacturers must develop an optimal manufacturing process for blue QDs – an effort that is likely to require strong collaborations between the materials suppliers and OEMs.

Furthermore, QD manufacturers have in general been struggling to simultaneously ensure uniform size and narrow emission peaks in order to prevent the QDs from blinking on and off.

Although a potential solution to this problem has been achieved by MIT researchers, the suitability of the new technique at commercial scale has yet to be verified.

Additional advances in technology are likely to solve some of the other existing problems with QDs in the coming years, leading to increased applicability of the technology.

In the immediate future, the QD industry is likely to focus primarily on the large display market, in which QDs are expected to be extensively incorporated in the backlighting units of LCD and LED-based TVs.

Moreover, NanoMarkets believes that the development of cost-effective mass production techniques will surely attract established OEMs that would like to harness the benefits of QDs in a variety of other applications ranging from direct-emissive QD TVs and smartphones to solid-state lighting.

However, NanoMarkets also expects that the potential for QD technology to replace OLEDs (in the large display segment) and LEDs and CFLs (in the lighting segment) will largely depend on demonstration of the long-term performance enhancements offered by QDs compared to these rival technologies, particularly in terms of their reduced manufacturing cost, enhanced power efficiency and color production, longer lifetimes, and flexibility.

*** End of Report: NanoMarkets: “Key Quantum Dot Markets

Note to Readers: To read more about a recent ‘Frost and Sullivan Award Winner’ in the advanced quantum dot (“QD”) manufacturing market, Frost & Sullivan recognizes Quantum Materials Corporation (“QMC”) with the 2012 North American Frost & Sullivan Award for Enabling Technology.

Read the Full Release online here:

http://www.frost.com/prod/servlet/press-release.pag?docid=271152906

 

MOUNTAIN VIEW, Calif. – Thursday, December 20, 2012 – Based on its recent analysis of the advanced quantum dot (“QD”) manufacturing market, Frost & Sullivan recognizes Quantum Materials Corporation (“QMC”) with the 2012 North American Frost & Sullivan Award for Enabling Technology.

QMC’s technology, employing an innovative tetrapod quantum dot continuous-flow chemistry process addresses the major challenges—low  production and corresponding high manufacturing cost—that have held back the wide-spread adoption of QD technology by major industries.

QMC’s process enables bulk manufacturing (95 percent to 97 percent full tetrapod yield) of highly efficient tetrapod-shaped QDs that have 4 arms on the QD core to enable better electrical conductivity compared to current QD technology.

The structure and size of the resulting Tetrapod QDs are highly uniform, which enables the narrow bandwidth light extraction accuracy of QMC’s quantum dots to be significantly higher than QDs manufactured through batch colloidal synthesis.

“Characteristics such as high quantum yield, smaller size and high band gap tunability make QDs an ideal platform technology for many emerging applications, such as solar energy, sensors, solid state lighting, quantum computers, and QD lasers,” said Frost & Sullivan Research Analyst Shyam Krishnan. “However, manufacturing inefficiencies of complicated, expensive synthesis processes have limited their adoption.”

(excerpt)

” …. In short, QMC’s technology has eliminated most of the industrial challenges facing large-scale adoption of QD technology. Moreover, the company’s unique synthesis eliminates conventionally used solvents, replacing them with cheaper and less toxic solvents that reduce the cost and improve the effectiveness of the process.

A major advantage of QMC’s Tetrapod QD manufacturing technique is its flexibility; it can fabricate Tetrapod QDs from 12 different elements, which allows for RoHS compliance,” observed Krishnan. “The process also allows for the width and length of the Tetrapod QD’s arms to be fine-tuned for any desired application. For example, short QD arms for biotech applications, and longer QD arms to improve electron transport in solar cells.”

 *** End of ‘Frost and Sullivan Release

 

 

 

 

Quantum Dot Company (Nanoco) Meteoric Rise

Shares in AIM 100-quoted technology company Nanoco have quite comfortably beaten every other stock on the market for the past three months and analysts think there could be more to come.

Nanoco Technologies: http://www.nanocotechnologies.com/

 

Manchester-based Nanoco makes what are known as ‘quantum dots’, or nano particles, which are used in televisions, lights and solar cells. More specifically, big name manufacturers of LCD TVs and LED lighting are beginning to use quantum dots in their products because they improve colour quality.

To illustrate this, in February Sony announced details of its new HD Bravia LED TVs which happen to use quantum dots from Nanoco’s competitor, QD Vision. Analysts viewed this development as generally positive for Nanoco because Sony’s adoption of quantum dots in its displays was seen as a ringing endorsement of the technology.

For Sony, however, the good news is limited because QD Vision’s nano particles are made using a heavy metal called cadmium, which is regulated to the point of being banned in some countries. So Sony will only be able to sell its new TVs in certain markets. The good news for Nanoco and its investors is that its quantum dots don’t use cadmium.

Janardan Menon and Eoin Lambe from Liberum Capital, concluded that the Sony development was “not particularly negative” for Nanoco and said they though that the likes of Samsung and LG were highly unlikely to use quantum dots containing cadmium.

Market re-rating

Nanoco originally floated on AIM in May 2009 after reversing in to then-cash shell Evolutec. Back then its revenues stood at just short of £2 million, with pre-tax losses of £0.78 million. By 2012, those revenues had risen only modestly to £2.95 million but losses had widened to £4.35 million. So what’s changed?

Its stellar recent performance began last December after a comparatively muted 12 months where the stock struggled to break out from a narrow range that peaked in March 2012 at 80p. By late February 2013 the shares were touching 199p and although they have retraced slightly, the stock remains around 100p ahead of where it was three months ago.

Behind that meteoric rise was an announcement in January that Dow Chemical Materials – part of the global giant Dow Chemical – had agreed to licence Nanoco’s quantum dots for use in TVs. Dow is a major supplier of electronic materials to the global display industry and is planning to boost manufacturing capacity in Asia to supply these products to its customers in the region. Full production is slated to begin in the first half of 2014.

While no financial details were released (they are expected later this year), analysts are agreed that the impact of this licensing deal will be significant for Nanoco. John-Marc Bunce at Nomura Code said it was likely that Nanoco would have sought “a significant multimillion dollar upfront licensing fee” for the global exclusive manufacturing rights and that the announcement should be seen as “financially significant”.

Liberum Capital described it as “a game changer”, with major potential customers like Samsung and LG likely to move much faster in adopting its quantum dot technology in their displays due to confidence in Dow’s high volume manufacturing capabilities. In response the broker raised its price target from 160p to 260p and maintained a strong buy recommendation on the stock.

In addition, Nanoco’s contribution (estimated at £10 million) to the capex required to establish the new production facilities may not need to be pulled from its current cash pile of around £15 million. Liberum reckons the costs should be covered by customer funding, customer pre-payments or from future royalty cash flows.

Consensus view

With a market cap of £366 million, Nanoco’s valuation has plainly lost touch with its fundamentals, with analysts setting price targets based somewhere between 20 and 25x 2016 earnings. House broker Canaccord Genuity claim that Nanoco is “a genuinely unique asset” with technology that could prove truly disruptive to the $100bn LCD market and as such warrants a ‘strategic valuation’. Its 275p price target is based on 20x estimated FY16 earnings – based on the assumption there will be no contribution from the Dow deal until FY15. Thereafter it estimates that revenues will grow fourfold in year one.

But not everyone is as bullish. Nomura Code, another broker, offers a more conservative view, raising its price target to 150p and predicting that the Dow deal could signal a short term peak in Nanoco’s valuation. Thereafter, its analysts “expect calculations of the timescales and real financial impact to potentially put a more restrained view on Nanoco’s near term value”.

Overall, there is a consensus view that Nanoco’s Dow deal will transform the company over the medium term and that other industry partnerships are likely to follow. After a three month surge, investors may now be waiting for more financial details, more deals and more revenue before driving the share price further. Nanoco’s interim results are due on 18 March.

How Quantum Dots could be in and will help your next TV

Nano-tech that could be in your next television

by Geferry Morrison: Posted February 18 2013

At CES in January, Sony announced several LCD TVs with “Triluminos,” a new backlighting method that they promise offered “rich, authentic color, and excellent red and green reproduction.” Digging deeper, it turns out Triluminos includes an optical component produced by QD Vision, Inc. called “Color IQ” which uses quantum dots to help create light.

OK, so what are quantum dots?

Quantum dots are a “semiconductor nanocrystal technology.” If you remember your high school (college?) physics, avail yourself of the Wiki page.

If you don’t know your valence bands from your conduction bands, you can think of a quantum dot as this: tiny pieces of matter with unique properties, including the ability to emit light at very specific wavelengths. Sort of like microscopic pieces of glitter that glow green, red, or blue depending on their size.

 

Red, green, and blue spectra for red, green, and blue quantum dots.

(Credit: QD Vision)

Specific wavelengths of light are good. We need specific wavelengths of light, the more specific the better. All televisions create an image by combining the three additive primary colors: red, green, and blue (RGB). Sharp adds yellow, a secondary color, but this isn’t in any content and is created by the TV. Mixing RGB in varying amounts gives us all the colors possible in our current TV system.

All LCDs create these colors with filters. Plasma displays create them with phosphors that glow in the required color (similar to the way CRT tube TVs worked). OLED, depending on the company, is one or the other. LG’s method creates a “white” OLED then adds color filters. Samsung‘s method has specific red, green, and blue OLED sub-pixels.

So where do quantum dots come in? Sony has a method.

Sony’s X900 and W900 lines Three of Sony’s 2013 TVs will use quantum dots in their backlighting, in the guise of QD Vision’s Color IQ tech (the 65X900, 55X900, and 55W900). A traditional LED LCD uses blue LEDs, coated with a yellow phosphor, to create “white” light. While reasonably efficient compared to other technologies (i.e. CCFL LCDs and plasmas), this still creates a lot of “wasted” energy. Orange, for example, doesn’t make it past the color filters on the front of the TV (instead, red and green are combined to create orange).

Triluminos uses blue LEDs, but instead of coating them with a yellow phosphor, the blue light from the LEDs passes through the Color IQ optical element containing red and green quantum dots. So the blue LEDs have two functions: create blue light, but also energize red- and green-emitting quantum dots so they in turn can create red and green light. About two-thirds of the light created by the blue LEDs is used to excite the QDs. Cool, right?

This diagram is a top-down view of one side of two edge-lit LCDs (the front is “up” in this case, the back is “down”). The upper image shows a traditional “white” LED (blue, with yellow phosphor). The lower image is the method used in Sony’s Triluminos: a blue LED that passes through red and green quantum dots. This RGB light bounces off the light guide, and out through the liquid crystal and other layers just like a regular LCD TV.

(Credit: QD Vision)

 

If you’re curious about how LCD backlighting works, check out Is LCD and LED LCD HDTV uniformity a problem? which has images and diagrams of how backlights work. Oh, and if the “Triluminos” name sounds familiar, Sony has used it before. This time, as shown, it’s referring to an edge-lighting technology, not the RGB LED backlighting as in 2008.

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Sony claims this allows for a wider color gamut compared to LCD TVs using “white” LEDs, as in more potential colors. Since all modern TVs are fully capable of reproducing every color in all current HDTV content, this is a bit of marketing hyperbole.

However, the benefits of this could go beyond cool, futuristic tech and WowNeeto-based marketing. When I’ve reviewed LED-lit projectors, I’ve found that the color possible from RGB LEDs looks more realistic than the same Rec. 709-calibrated colors created by color filters (DLP) or dichromatic mirrors (LCD/LCOS) as lit by UHP lamps. One TV engineer I asked about this phenomenon replied “LEDs are like painting with purer paint.”

Our own David Katzmaier often remarks in his reviews on the bluish cast seen on some conventional LED-based TVs compared to, say, plasma sets. “It’s usually most prevalent in dark areas, but I sometimes see a slight bluish ‘coldness’ in brighter material and skin tones too. In some cases I see it despite seemingly excellent color measurements from my instruments.”

So it’s possible that even with the same measured color points, quantum dot-enhanced displays could produce more realistic color. Will they? Will the color mixing required to create Rec. 709 from wildly oversaturated color points cause other issues? What effect will the color filters, which are still necessary on LCDs, have on this “purer” light? These are questions we can’t answer until we see the X900 series, and any future TVs with quantum dots.

This whole column and not one “Quantum Leap” joke. Oh dammit.

 

Atomic Force Microscopy (AFM) image of sparse QDs (white) on a semiconductor background (black). Individual QDs, as well as close-packed small groups can be resolved.

(Credit: MIT)

The current generation of quantum dot technology requires a primary light source like the blue LEDs in Sony’s Triluminos. This won’t always necessarily be the case. It will be possible to excite the quantum dots directly. This could be a full QD backlight, but it could be more. How about a direct-emissive display like OLED, but instead of Organic Light-Emitting Diodes, it’s sub-pixels filled with red, green, or blue quantum dots. QD Vision calls this a “QLED,” and it could have similar performance characteristics as OLED (like a truly infinite contrast ratio). Will it be easier to produce, offer better color, or have even lower power consumption? At this point, we have no idea. Given the production difficulties OLED has had, just the fact that there’s something on the horizon that could offer potentially similar performance is exciting.

Bottom line Unlike many of the new technologies on display at CES every year, quantum dots are real, and are potentially very cool. For now they reside only in a few high-end LCDs, but like OLED, they could hint at what a display of the future might be. Will they? We shall see.