Nanoco Brings Alternative Quantum Dot Solutions To 4K UHD TV
Nanoco’s Brian Gally presents two TVs using the company’s quantum dot technologies.
Quantum dot technology has received a lot of ink from Samsung’s SUHD and QLED 4K Ultra HDTVs, as well as from competitive versions introduced several years ago by Sony in association with QD Vision followed later by Hisense, TCL and others.
The names behind these nano-particle sized dots that emit bright colored light in LED-backlit LCD TVs have thus far focused around Nanosys, QD Vision and Samsung, which has its own quantum dot properties in addition to working with others.
A lesser-known, though equally large player in the quantum dot field for large display devices is Nanoco Technology, which made its first formal appearance at CES 2017. Hardly a newcomer, Nanoco was among the first to develop environmentally friendly cadmium-free quantum dots for consumer television displays back in the mid-2000s.
Quietly, it has been supplying quantum dot solutions used as coatings for a sheet of film that is sandwiched into an LCD TV panel stack to help advanced LED LCD TVs produce a wide color gamut to go with the brightness boost needed for high dynamic range (HDR).
Nanoco, which is based in Manchester, England, has manufacturing operations in Runcorn. It has been setting the stage for the next evolution of LCD TV technology, and while Samsung — which recently acquired QD Vision, and holds a stake in Nanosys — appears to be quickly cornering the quantum dot television market, Nanoco is providing an alternative, which is already being used in televisions from TCL, Hisense and Philips (the latter under license to China-based TPV).
We caught up with Nanoco’s executive team at CES to find out when we can expect to see televisions in the U.S. market using their technologies. The following interview sheds some light on where quantum dot market is headed and how Nanoco is helping to shape it.
Read the interview after the jump:
Q: How is Nanoco’s technology different from what Samsung has been using in its SUHD and QLED televisions?
Keith Wiggins, Nanoco Technologies chief operating officer: Samsung has a stake in Nanosys and recently acquired its rival QD Vision. It also produces its own quantum dots. The key value differentiator for Nanoco is twofold: one is a process that allows quantum dots to be scaled reproducibly, economically better than anyone else. So traditionally to make quantum dots there’s a dual-injection process. This is an exothermic reaction, and where the property of the quantum dot [the color] is determined by the size of the particle, you must control the process where you make the particle by design. Using direct injection, you end up with a whole mix and distribution of particles, which you then have to separate and reprocess. That adds a lot of cost. Our technology is absolutely scalable making it the process of choice for where the industry is headed.
Our technology uses a color conversion film coated with quantum dot resin. In one of our approaches, instead of having a traditional type LED to give you a white backlight we use a blue LED. We put our film in just the same as manufacturers put optical films in a TV. Our film converts the blue light of the LED to white. Because of the properties of quantum dots the white light produced is a much better white light for showing color.
The quantum dots we produce are semiconductor nanocrystals and the wavelength of light they emit is determined by particle size. They are absorbers of broadband radiation and emitters of monochromatic light and that monochromatic light is determined by the particle size.
What we do is manufacture those quantum dots. They are put into a device that effectively creates a matrix structure sandwiched between two barrier films and then that slots into the stack of the [LCD TV panel]. In combination with the blue LED back light a red/green film will enhance color.
Brian Gally, application technology head, Nanoco Technologies: We use a seeding process with a uniform seed followed by a growth reaction which is now much more controllable. So you have a very controlled process and a process that you can run in a very large batch size. That’s really what the company was founded on originally and later on we made the shift to developing cadmium-free quantum dot material.
Q: Samsung has required that its quantum dot technology also be cadmium free. Why is this important to the industry?
Gally: The market is moving away from cadmium because of its environmental and risk profile. On that basis, there is a key differentiator for us, and Samsung, who is the major player in the quantum dot space and using cadmium-free quantum dots. The rest of the approaches out there have cadmium in their product. QD Vision was acquired by Samsung recently basically because it failed. That failure was due to the fact that their primary offering in the market was cadmium based.
Q: What is the advantage Nanoco offers the market to compete with Samsung?
Gally: Quantum dots have been talked about in terms of integration into the television in more than one way. Film is what we are doing, and the film is placed into the backlight stack. The other path that people talk about is the rail. You put the quantum dots basically into a capillary and you place that effectively between the array of LEDs and the light guide plate and that’s where you do the color conversion. So you have a blue LED and it goes into the rail past the green and red in the quantum dot and it goes into the light guide plate. QD Vision was the one promoting that. That has effectively gone away. Film is the path that works best. The whole aim of quantum dots is to improve the image quality of the LED. It improves the gamut.
The other technology people use to improve the image quality is to enhance the blacks. You see that in the local dimming of the [back light unit] BLU. If you are using a rail model, that doesn’t work with local dimming. Only a film is going to work with local dimming.
For our approach, it doesn’t matter if the panel is edge lit or full-array LED back lighting because it goes into the BLU stack. It’s fully compatible with everything that an LCD maker is going to want to do to improve image quality, and our component slips into that and improves the color gamut.
We have a couple of technology approaches we offer to different customers. In one, instead of using a blue LED with a yellow phosphor, we put a blue LED against blue and the green quantum dots. This gives off blue RGB light which is saturated red, green and blue and that’s matched to go through the color filters of the LCD, as opposed to sending a broad white light directly through a color filter. This is a similar, though not identical, technology to what we think Samsung is employing.
We are working with several TV makers so our first technology uses an RG film – Wide White Film, we call it. There is an intermedia which is a green film and there the TV producer will use a red/blue back light which gives off magenta, effectively. A combination of red and blue LED with a green quantum dot film and that brings properties which certain customers require in terms of color enhancement, and some enhancement on brightness which comes from the forward half mix of the red LED component.
Q: Where do you stand in cost compared with the other quantum dot solutions out there?
Gally: When you look at the actual quantum dot component then cost is a function of volume and volume is a function of the environment, customer demand etc. We’ll be lower in cost than anyone else in the market. The market still is absolutely in the early phase of its ascendancy.
We also bring an energy benefit, cost to the consumer, cost to the manufacturer and a picture enhancement benefit.
Q: Who are Nanoco’s customers?
Gally: We have two ways that we bring our quantum dot technologies and our manufacturing processes to market. One way is to manufacturer the quantum dot resin, which we sell to a film-coating company. Then, we’ve also licensed our technology to Dow and Merk, which manufacture and sell quantum dots based on our technology. Dow and Merk sell their quantum dot films to television manufacturers. As for the quantum dot resin that we make ourselves, we have licensed our technology to Wah Hong, a Taiwan-based film coater. We provide Wah Hong with the quatum dot resin we produce, and they convert that into a film –We don’t do the film coating—and they then sell the quantum dot film to television manufacturers.
Q: Can you quantify for us how much of the visual color spectrum your quantum dot technologies can cover and what peak luminance and black levels they can help a television achieve?
Gally: What a set will generate in terms of peak luminance and color will depend on the set. So for example, how much energy I put in will determine how much peak luminance I can generate. But some examples include a Hisense set with 102 percent of NTSC, a TCL display with 96 percent of DCI and that also will depend on the color filter. Different color filters will give you a different result.
As you push out towards the Rec. 2020 color gamut standard the set is going to be less bright, so depending on the color filters that people use we can go wider in DCI-P3– up into the upper 90 percent area, and the technology will eventually get you to 90 percent of Rec.2020. It depends on what you want to do there. The most typical application going through color filters will be in the high 80 percentage range, and our technology roadmap takes us over the 90 percent threshold.
Q: Can you detail for us where Nanoco’s technology roadmap is leading?
Gally: The road map would be film first, quantum dot color filters next and then electro-luminescence.
Quantum dots have a long road map inside displays and TVs. As we have said, film was one of the first implementations of that. But there may be other ways of integrating that into the system. The next big step is to put quantum dots directly into the LCD color filter material. The benefit there is that you don’t need to convert some white light. Because in today’s [back light units] BLUs you have full white light, and that goes through the color filter. So, in this case now, you have a blue backlight and then at each subpixel is where you have the conversion. So in other words, at the green, I’m going to convert that blue backlight into green. Where I have the blue, the blue from the backlight obviously just passes through and where I have red, I have to convert that blue light to red. But where I have not converted that light to red there I have to filter it out in the blue and the green color filters. So there’s a big efficiency gain when I put the quantum dot material directly into the color filter. That would be the next place where we see the dots going into the TV.
Using quantum dot film the benefit is expanding the color gamut, but if you use the color filter approach it would also benefit off-axis viewing. You would put it outside the polarizers. In the color filter approach, you bring the second polarizer inside the cell, and then the color filter would have the dots, and because of the way the dots emit light in all directions you now have something much more lambertian. In addition to the efficiency benefits that geometry is going to have some benefits for viewing angles as well.
So today, who captures the value from the wide color gamut technology? It’s the set maker because the set maker puts the BLU in the TV set, or if the set maker is doing a phosphor solution with advanced phosphors, he is putting the phosphor on the LEDs in the BLU. This quantum dot color filter approach brings it back to the panels. So, I think we’ll see the panel makers really want to adopt this in the future.
The ultimate TV would be a direct emissive form of quantum dot technology were you would replace the organic quantum dot material with an inorganic quantum dot. Obviously, that technology is further out on the horizon.
Q: Other manufactures have used the term QLED as a label for that coming direct-emissive quantum dot technology, but Samsung has just announced QLED as the name of its current quantum technology. What did you think about that?
Gally: QLED was a trademark that QD Vision owned. Samsung recently completed the acquisition of QD Vision, so Samsung can now do anything they’d like with the trademark. [Editor’s note: Samsung acquired the QLED trademark after QD Vision let it lapse last summer, and prior to Samsung taking over QD Vision at the end of the year]. Really, QLED is just another term in the industry that generally means quantum dots. Samsung has used it as a replacement for what they were calling `SUHD TVs’ last year. It’s Samsung marketing, akin to what some TV makers were doing when they called their LED backlit LCD TV `an LED TV.’ The terminology misled some people into thinking a TV was using LED technology, when it was not. It was just an LCD TV with an LED backlight.
By Greg Tarr
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