Commercializing High-Information-Content Flexible Displays: A Global Initiative

by Greg Raupp

For years, the compelling advantages of flexible-display technology have driven display developers, manufacturers, and market analysts to make a wide range of predictions on their market entry point and time and their global market impact. Now that the release¹ of the first commercial product with a high-information-content flexible display, Polymer Vision's Readius, is visibly on the horizon, we have finally arrived at the dawn of the flexible-display revolution.

At some level, flexible displays have already entered the commercial marketplace through such products as Motorola's Motofone handset, wristwatches, and smart cards. However, these displays provide relatively low information content and, from a technology perspective, are direct-drive, segmented, or passive-matrix displays. The significance of the Readius product introduction and other exciting products soon to follow from other manufacturers is that the display is of the active-matrix high-information-content type that consumers have become accustomed to in their e-readers, PDAs, and feature-loaded mobile phones.

This significant commercial market entry and others soon to follow² have encouraged market analysts to adjust their market forecasts upwards. For example, in a recent report, iSuppli predicted a 35x total market increase from 2007 to 2013 for flexible displays to $2.8 billion.³ Only slightly more than a year ago, the company was predicting a much smaller $340 million total market by 2013.

I am often asked at conferences and workshops, "What is the 'killer app' for flexible displays" that will dominate and drive technology acceptance and growth? As a not-for-profit technology developer (and not a commercial product developer), I am not well-qualified to answer this question and will be the first to admit I do not comprehend all that it takes to bring a new consumer product successfully to market. It is exciting to note that the new products soon to be released break free from existing "information scaling laws" that state that the amount of information visually presented (or size of display) must scale with product size. It is clear to me that in the highest level vision of the technology revolution, the new product opportunities are limitless since once a high-information-content display is fabricated on the proper flexible substrate, the display, in principle, could be placed on any surface, anywhere! This newfound design freedom should catalyze the creation of a whole new generation of user-friendly and highly desirable products that will change the way we access and share information and entertainment. In this context, I read with great interest the cover story of the July 2008 issue of PC Magazine⁴; it seems that many concept designers are already embracing this freedom in that all the "amazing gadgets that will change your life" detailed in the article incorporated a flexible display as a critical enabling feature.

So what is the killer app? When will it enter the market and how "killer" will it be? With apologies to Yogi Berra, predictions are always risky, especially when you are talking about the future. So rather than speculating on future products and markets, let's instead focus on the answer to a more straightforward question that merely requires 20/20 hindsight: "How did we get here, in 2008, to the brink of flexible-display commercialization?"

A Global Initiative

A host of organizations across the globe and countless individuals within those organizations have contributed to this signal moment in display-technology history. Although there are major regional distinctions between the organizations as highlighted below, there is also a crucial commonality. Within any given region – Asia, Europe, or the United States – the spearheading organizations have leveraged their historical place, resources, and cultural heritage to drive the technology development in a way for which they were best positioned to achieve success.

Regional Differentiation

In Asia, historically, the home to flat-panel-display (FPD) manufacturing and with a culture willing to risk large manufacturing infrastructure investment, Tier 1 manufacturers LG Display and Samsung Electronics in Korea and Sony and others in Japan, as well as niche/custom display-manufacturer Prime View International (PVI) in Taiwan, are leading the way. These companies are funding their efforts internally through aggressive re-investment of a portion of the large revenue streams generated by their conventional glass-based FPD manufacturing fabs. They are heavily leveraging their years of accumulated experience with amorphous-silicon (a-Si:H) thin-film transistor (TFT) technology and working to transition that powerful know-how to flexible-display manufacturing.

In Europe, home to storied hundred-year-old-plus technology corporations and venerable academic institutions, Philips spin-out Polymer Vision and Cambridge University start-up Plastic Logic are the primary innovators. With the dominant position of Asia in a-Si:H technology, these relatively young European companies are pursuing a different path by pioneering the integration of organic thin-film-transistor (OTFT) materials and devices in displays. Funding comes from venture-capital firms and government sources eager to see the associated new manufacturing approaches and potentially disruptive technology succeed.

In the U.S., the historical home to new technology invention and major FPD materials and manufacturing supply-chain companies, but without a domestic display-manufacturing base, the Flexible Display Center (FDC) at Arizona State University, a not-for-profit government/industry/university consortium, is the tip of the spear. Following a long tradition of substantial military investment in the creation of new display technology, the U.S. Army Research Laboratory established the FDC in 2004 through a 10-year cooperative agreement with Arizona State University to accelerate the commercialization of flexible displays.⁵ To achieve this objective, a world-class partnership framework was designed, and a network of more than 20 actively collaborating and financially contributing industrial members has been implemented. A dedicated state-of-the-art facility and manufacturing pilot-line infrastructure have been established to create a unique venue and national asset for the partnership to co-develop advanced technology and associated manufacturing processes. As a not-for-profit organization, the FDC can afford the luxury of being somewhat more technology-agnostic than commercial technology-development organizations. In the short term, efforts focused on developing the associated flex-compatible materials, tools, processes, and protocols to rapidly and cost-effectively transition a-Si:H TFT glass-based manufacturing infrastructure to fabrication on flexible substrates. However, with a look to the future and potential enabling or even disruptive technologies, parallel longer-term work on such topics as alternative break-out TFT technologies and roll-to-roll compatible processing is being actively pursued.

Global Interconnectivity

Which of the ground-breaking efforts described above will enjoy enduring success is impossible to judge at this moment in time. From the perspective of a customer – be it military, a display technology integrator, or the individual consumer – the best short-term outcome will be that all will be successful. In that context, there is a tremendous level of interconnectivity and interdependence between the efforts in the different geographic regions. For example, Philips in Europe has licensed an enabling display fabrication on thin-film spin-castable plastic protocol it calls EPLaR^™ to PVI in Taiwan. EVG, an Austrian company with North American headquarters in the FDC facility and an FDC-member company, has recently sold production-level large-area organic coating tools that were developed in collaboration with the FDC to Plastic Logic for its new fab to open this fall in Dresden, Germany. Professionals at DuPont-Teijin Films in Japan and the U.K. have been working with the FDC to develop a "display-quality" engineered high-temperature polyester film that is now available as a commercial product, Planarised PEN^™, for any flexible-display technology developer or manufacturer. LG Display has recently become an FDC member, and we are already collaborating actively on improvement of flexible metal-foil substrate systems. These are just a few of the many examples of the complex interconnectivity and interdependence of the global effort that will no doubt grow in number and impact as commercialization is fully realized.

Postscript: Back to the Future

Despite the tremendous advances and successes realized in the past few years, there is still much work to do. For the first generation of ultra-low-power daylight-readable e-paper reflective displays soon to be mass-produced, manufacturers will need to work through throughput and yield issues. Cost-effective flex-compatible processes and materials for color filters will need to be developed because many applications will require, or the consumer will demand, full-color displays.

An entirely new set of problems will arise as the different organizations focus more attention on the more-challenging emissive OLED displays still under development. Anticipating that neither a-Si:H TFTs or OTFTs will meet the demanding performance requirements of OLEDs, alternative flex-compatible TFT technology will need to be developed. Robust flexible barrier and encapsulation films and associated cost-effective low-tact-time processes will likewise need to be developed.

As for the technology development and commercialization efforts to date, it is likely that we will see differentiation by region as different organizations construct individualized roadmaps and pursue competing paths that leverage their unique historical place and core competencies. This healthy competition, coupled with strategic cooperation and interconnectivity, should drive the community to collectively arrive at effective solutions.

References

¹Scheduled for market release in Europe in Fall 2008 and in the U.S. in early 2009. Source: "Electronic Papyrus: The Digital Book, Unfurled," The New York Times (July 6, 2008).

²"New E-Newspaper Reader Echoes Look of the Paper," The New York Times (September 7, 2008).

³"Emerging Display Technologies," iSuppli Corp. Report (2008).

⁴"Future Tech: Seven Technologies that will Touch Your Life," PC Magazine 58-66 (July 2008).

⁵D. Morton and E. Forsythe, "Flexible Display Development for Army Applications," Information Display 18-23 (October 2007). •