Display Week 2010 Review: Green Technology

Environmentally friendly devices, processes, and materials are growing ever more important in the display world.

by Jenny Donelan

THERE WERE so many shades of green on the show floor at Display Week 2010 that you might have thought it was St. Patrick's Day in May. The green was virtual, of course, but virtually every company had a tale to tell about its environmentally friendly products and processes. It would have been an interesting exercise to ask every exhibitor if it had anything green to say about its products or operations; very few would have answered "no." Not only is green a must-have label these days, it's a fairly easy one to attach: whatever the motivation, most companies are doing at least something less wastefully or more economically than they used to, and almost all of it makes for a green story of some kind.

This is not to say that most of the stories are not true, or important. In fact, the relevance of green was underscored this year by the introduction of the Display Week 2010 Symposium's first Green Technology track, which featured 20 papers covering topics ranging from power-saving components to gas output reduction during manufacturing to newer and more efficient device structures. One way to bring order to all these green initiatives is to sort them into categories, as was proposed in the Symposium paper, "Green Technology in LCD" (Paper 9.1) by Jun H. Souk and Sangwoo Whangbo from Samsung Electronics' LCD Division. The authors separated green technologies in the LCD industry into three areas: green devices, green processes, and green factories, as shown in Fig. 1.

Noting that LCDs continue to be used in more and more applications, and that increased production capacity from Gen 8 or Gen 10 lines in LCD factories is driving the consumption level of chemicals and power higher than ever (while at the same time overall environmental awareness on the part of consumers and governments is increasing), Souk and Whangbo note that LCD manufacturers need to be especially observant. For example, the SF₆ gas used during the dry-etch process has a very high global-warming potential, the authors noted, adding that Samsung had been able to reduce the output of that gas by about 85% through retreatment techniques. CO₂ outgas reduction is also obviously necessary for LCD companies as well as for other types of manufacturers. Out of all the above factors, the most effective areas for change, note the authors, are the reduction of greenhouse gases during the manufacturing process and the creation of power-saving LCD devices that use features such as higher light transmittance panels and local dimming with LEDs.

Keeping in mind that since it is not possible to tell all the green stories from Display Week 2010, a few examples from some representative technology areas at the show are described below.

LCDs

In the paper, "EcoDesign for TV Displays " (Paper 9.4) by Kees (Cornelis) Teunissen, Theo JM Schoenmakers, and Leendert Jan de Olde from Philips Consumer Lifestyle, the authors compare a typical 32-in. CRT television from 1999 with a typical LCD TV of today. The former weighed about 20 kg and consumed 150 W, whereas the latter weighs about 11 kg and consumes less than 90 W. That said, 32 in. was a good-sized TV 10 years ago; today, the LCD TVs consumers seem to covet are far larger, and therefore consume more energy than their smaller counterparts. So now that CRTs have been replaced, a further switch is being made from CCFL- to LED-based backlighting for LCDs. This is also a green story. For one, CCFLs contain heavy metals that make them more problematic to dispose of than LEDs. And LEDs, especially in edge-lit formation, are generally more efficient.

However, it was not energy efficiency that drew the most "oohs and ahs" on the show floor. Those reactions went more to products such as LG's 84-in. 3-D TV (read more on the energy-usage implications of 3-D LCDs in our Septem-ber issue). But in its 'Next-Generation Display Zone' at the show, LG also featured a 15.6-in. notebook LCD product that the company claimed "realizes the world's lowest power consumption levels." According to the sym-posium paper on this technology, "New Driving Method for Low Logic Power Consumption in TFT-LCDs" (Paper 43.2) by LG Display Company's Sai Chang Yun et al., this was achieved with a new driving rate method that resulted in 53% power consumption compared to a unit using conventional driving methods.

e-Paper

It wouldn't be right to discuss green displays without at least a mention of e-paper and OLEDs, although this issue of Information Display features separate articles on these technologies. e-paper and OLEDs each offer some tempting alternatives to LCDs, both in terms of power usage (e-readers based on e-paper can hold a charge for weeks, for example) and display performance. But both also have drawbacks. e-paper is not quite ready to handle full color and video and OLEDs face some manufacturing hurdles. Nonetheless, one of the most impressive sights at Display Week was simply the latest generation of E Ink's monochrome E Ink, "Pearl," which enables visually pleasing imagery with high contrast and sharp definition. It is an example of an evolutionary improvement that could just be what it takes to make more people buy their first e-reader. The Pearl E Ink, which actually increases contrast by 50%, is used in Amazon's newest version of the Kindle DX (the company literature also says Pearl saves more power than the previous generation of E Ink, but does not provide figures) (Fig. 2).

Fig. 2: The latest e-reader from Amazon, the Kindle DX, features a low-power reflective display based on the latest E Ink technology from E Ink. Image courtesy Amazon.

Materials

One of the most visible green proponents at the show was liquid-crystal developer Merck KGaA out of Germany (factory shown in Fig. 3.) Also using the "triple green" theme of materials, processes, and devices, Merck was handing out "Green³" pamphlets that highlighted the company's green activities, such as CO₂ reductions (Merck's goal is to reduce them by 20% between 2006 and 2020). The literature also focused on advanced LC materials that reduce backlight power, prolonging battery life for mobile units and reducing power consumption for all devices. Merck also makes reactive mesogen materials that canbe used to improve the brightness of VA-, IPS-, and TN-mode LCDs.

Fig. 3: Merck's liquid-crystal production facility in Darmstadt, Germany, is the site of some of the company's green initiatives. Image courtesy Merck KGaA.

Many other companies were also featuring optical coatings and/or glass designed to brighten or otherwise improve display performance, in many cases reducing power usage. These include 3M, Berliner Glas KGaA, Corning, Dontech, Dupont Display Enhance-ments, and Sony Chemical, just to name a few.

Packaging

Among all the high-tech green initiatives, it is important to remember that some of the changes with the biggest impact happen at basic levels. Elo TouchSystems, for example, a major developer, manufacturer, and marketer of touch-screen and touch-monitor products, had a packaging and materials story to tell. According to Elo's Keith Pradhan, Director of Product Management, the company has begun using recyclable aluminum and steel chassis. "We've also been looking at recyclable plastic," he says, "but that tends to soften." In addition, the company has redesigned its packaging so as to fit more units on a pallet and thus save shipping costs as well as waste. As is the case with so many green initiatives that actually see the light of day, this one saves money in addition to being good for the environment.

Green Light Ahead

Many of the "greenest" advances are still in the laboratory. Companies such as Merck KGaA are espousing the possibilities of materials such as organic TFT, which does not require the large amounts of chemicals, waste water, gases, etc., that conventional a-Si on glass does. OTFT can be solution–processed by ink-jet printing directly onto plastic substrates. Another promising LC technology, according to Merck, is blue phase, which should reduce the number of required fabrication processes, thereby cutting down on production energy usage and cost. (For more on blue phase, see "Blue Phases for LCDs Based on Isotropic-to-Anisotropic Transitions" in our November 2009 issue.)

Green may seem like the fad of the day. But with environmental awareness becoming increasingly important to consumers and governments, it is unlikely that attention to things green will fade. Even if environmental concerns wane temporarily, as they tend to do, there is always the bottom line. If being green saves money for manufacturers (and does not necessarily cost the consumer more), the greening of displays will continue. •