Plastics, nanotubes, and the mobile displays of the future.

It no longer takes much foresight to imagine the mobile world of the future, a world in which smart phones and other handhelds combine voice and data communications, with a considerable amount of computing capabilities. Video will be part of the mix, too.

Different handheld devices will have different orientations, of course. There will be PDA-like devices focusing on data; iPod-like devices that are video capable; and advanced cell phones that, for all their additional functionality, in the end are just voice machines. Despite these different strengths, the multifunctional handheld devices of the future are going to require much better displays than the small LCD screens typical of handhelds in the past.

There are some good historical reasons to think the contributions made by advanced materials are the key to the display needs of the handheld sector. It was the advent of good LCD screens that made mobile computing possible. LCD was also the main enabler of large flatpanel displays (FPDs) for television, and then the arrival of plasma made those FPDs even better.

It is therefore not surprising those looking for better displays in the handheld sector have focused on new materials platforms. Solutions offered include MEMS, liquid-crystal-on-silicon, and field emission displays (FEDs). These, however, have usually brought new problems in their wake--high power usage, visual distortions, and so on. But in the new NanoMarkets report, "The Market for Flexible Displays and Field Emission Displays: How Plastic Electronics and Carbon Nanotubes are Creating New Opportunities in the Display Business," we examine the impact of nanotube electronics and plastic electronics, two technology/materials platforms we believe are on the verge of producing a new generation of displays that preserve the achievements of the current level of handheld display technology, while solving some problems handheld displays now face.

Plastics, displays, and printability

Plastic electronics is an emerging technology/materials platform in which circuitry is created with conductive molecules that are somehow layered onto a substrate. In the case of displays, the light is supplied by a layer of organic LEDs (OLEDs). There are, however, outstanding materials and technology issues yet to be settled that will ultimately shape this sector:

Vapor deposition versus inkjet

In terms of manufacturing, the two options for plastic displays seem to be vapor deposition and inkjet printing. Vapor deposition is a highly mature process and is, for example, being used by Eastman Kodak Co., Rochester, N.Y., to create its plastic displays.

The alternative is inkjet printing, using industrial inkjet printers. Based on our interviews, there still seems to be some controversy about just how mature inkjet printing really is at the present time. There can be little doubt inkjet printing is the holy grail of plastic electronics, since it seems to change the economics of manufacturing in electronics from favoring very high production runs in massively expensive fabs, to an environment in which modest runs are profitable and circuitry can be easily customized. This will impact not only the display business, but also RFIDs, membrane keyboards, computer memory, and photovoltaics.

Manufacturing technology in state of flux 

Whatever the current merits of inkjet versus deposition approaches may be, both approaches are improving. Backers of inkjet technology point out that once plastic electronics takes off, specialist inkjets for plastics electronics will appear and help improve yields.

At the moment, general-purpose printing machines are being used. One design direction for specialist inkjet printers aimed at the plastic electronics market would be designs with printheads optimally suited to polymer or metallic inks.

Materials technology is immature, too

Universal Display Corp., Ewing, N.J., is touting its display technology that uses small molecules to create phosphorescent OLEDs. It claims good color quality, but is using a vapor deposition process to create displays. Cambridge Display Technology Ltd. (CDT), Cambridge, United Kingdom, uses polymers and the potentially revolutionary inkjet process. But it is still working on long-lifetime blue OLEDs. A materials platform that can produce inkjet printable displays with high color quality that will also last a few years still seems like a thing of the future.

Plastics, displays, and flexibility

The future evolution of plastic display technology will also occur not just in the materials for OLEDs and the production technology, but in the materials for substrates as well. Although many people use the term "printable displays" and "flexible displays" as interchangeable terms, they are actually different. OLED displays, even if they are printed, do not necessarily use a flexible substrate. Fujitsu Ltd., Tokyo, Japan, is using a color OLED subdisplay in one of its cell phones, but the substrate is glass.

Using a plastic substrate instead of glass reduces weight and makes displays less likely to break when a mobile device is dropped. These are important reasons for moving to a plastic substrate. But what a plastic substrate also does is enable flexibility in addition to printability.

Some firms, such as CDT, E Ink Corp., Cambridge, Mass.; Philips Semiconductor, Eindhover, The Netherlands; and Plastic Logic Ltd., Cambridge, United Kingdom, are working towards displays that employ a flexible substrate and, hence, can be rolled up just like paper. The term "electronic paper" has been coined for this type of product, which is paper-like not only in its flexibility and thinness, but in its ability to be read from many angles. Some research and development work is even being done to make "electronic paper" feel like paper.

Flexible displays that can be rolled up may be no more than a novelty in the general cell phone sector; but for a high-end smart phone with extensive computing capabilities or a miniature video player, the ability to roll-up a medium-sized display and unfurl it for use may have a lot of value.

Trying to watch a movie or search a website on a display that measures just a few square inches could never be a pleasant experience, and the roll-up display means a laptop-sized device no longer is essential if something other than a tiny screen is required. A roll-up display would enable a much larger display to be used than would be possible if a rigid display was being used, and would bring the viewing experience closer to what a consumer would be used to with a television screen.

A role for CNTs?

NanoMarkets research also suggests carbon nanotubes (CNTs) may have a role to play in displays for future mobile devices. This may occur either as part of the plastic display programs described above or as an alternative to such programs.

One possibility is to use a CNT composite as an alternative to the sputtered indium tin oxide (ITO) used to conduct electricity to cells in either glass or plastic displays.

This has been proposed by Eikos Inc., Franklin, Mass., which claims the advantages of using its composite over ITO include improved flexibility, printability, and color. Cost can also be reduced, according to Eikos, since vacuum processing is not required and the Eikos approach effectively replaces indium (a scarce commodity) with carbon (an almost ubiquitous element). DuPont, Wilmington, Del., has also worked in this space and has developed a polyaniline/CNT composite the company says is suitable for printable electronics in display backplanes.

And although plastic/flexible displays seem certain to be the next big thing in mobile displays, it is possible they may be challenged by CNT-based FEDs by late in this decade. Just a few years back, FEDs were being seriously considered for the mobile sector.

The FEDs of the time, however, utilized a kind of microtechnology that ultimately floundered on technical problems. FEDs have now been reinvented using carbon nanotubes. They operate on a similar principle to CRTs; but they are lighter, less power consuming and flatter, and they also boast very high-quality video display.

This new generation of CNT-based FEDs is not being aimed at the mobile sector. Instead, they will first appear in the form of large television screens and advertising displays, which are segments of the display market that most manufacturers believe will be willing to swallow their relatively high research and development costs. Given the high quality of the FEDs video output--which may well surpass what plastic electronics can offer--coupled with low weight and power consumption, it would be no surprise to see FEDs return to the mobile segment eventually. At least one firm, cDream Corp., San Jose, Calif., says it already has plans to enter that sector; and others may follow once FEDs have moved down the cost curve.

Bottom line

In a recent presentation to a nanotechnology business conference, an executive from Motorola Inc. told the audience the most important problem to be solved before ubiquitous computing could become a reality was finding better power sources, since the current generation of lithium-ion batteries were not up to the task. According to this source, however, the second-most important problem for most ubiquitous computing was better displays, meaning ones that could more adequately show high-quality videos and images, as well as serve for note taking, etc.

In a multimedia mobile world, displays will be required to serve multiple purposes and provide effective information output. The emerging generation of displays being enabled by the latest developments in material science will go a long way to meeting such requirements.

About NanoMarkets

NanoMarkets LG, Sterling, Va., analyzes the market opportunities and disruptions brought about by advances in technology at the micro and nano scale. The company looks at both established and emerging markets with a focus on the realms of electronics and semiconductors, bio-medical devices, energy and advanced materials. Through its reports, white papers, and customized client engagements, it provides analyses of the commercial and technology-related issues that will determine where and how business opportunities will emerge or be impacted.

RELATED ARTICLE: Next generation displays will generate $3.4 billion by 2009.

According to the new report, "The Market for Flexible Displays and Field Emission Displays," from NanoMarkets LC, Sterling Va., new materials, such as carbon nanotubes and organic molecules with conducting/semiconducting properties, will enable a new generation of displays that will create $3.4 billion in annual revenues by 2009.

The many new functions performed by mobile phones and other handhelds mean this sector is desperately seeking low-power, high-quality display solutions. Motorola Inc. has identified this as a key challenge for ubiquitous mobile computing and communications to become possible. Plastic electronic displays based on organic LEDs and circuitry will meet this challenge and also enable flexible, paper-like displays that can be unrolled and connected to handhelds when needed, thus enhancing the visual output for smart phones, portable video devices, and industrial/medical handhelds.

As a result, a fledgling plastic display industry is emerging, including firms such as Cambridge Display Technology Ltd., Eastman Kodak Co., Philips Semiconductors, and Universal Display Corp. According to NanoMarkets, the mobile phone/handheld sector alone should generate $2.2 billion in plastic displays revenues by 2009.

NanoMarkets new report says, while some circuitry for plastic displays may use carbon nanotubes, the biggest opportunity for CNTs in the display sector will come from field emission displays (FEDs), which may provide the first mass market for CNTs. FEDs provide the high-quality images associated with CRTs, but without the problems of burn in and poor viewing angles associated with current flat panel displays. Samsung wilt bring large FEDs to market next year. Other companies developing FEDs include LG Corp., Mitsubishi Corp., Toshiba Corp., and various start-ups. The new NanoMarkets report says, while the initial impact of FEDs will be on televisions, FEDs are also being considered for large advertising displays and even mobile computing. By 2009, NanoMarkets expects FEDs will generate more than $700 million in revenues. Visit www.nanomarkets.net.