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OLEDs, OXIDE TFTs, AND DISPLAY WEEK PREVIEW ISSUE

Mar./Apr. 2013 Official Monthly Publication of the Society for Information Display • www.informationdisplay.org Vol. 29, No. 2 Thin Films pC2_Layout 1 3/22/2013 2:40 PM Page C2

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SOCIETY FOR INFORMATION DISPLAY Information SID MARCH/APRIL 2013 DISPLAY VOL. 29, NO. 2 ON THE COVER: This year’s winners of the Society for Information Display’s Honors and Awards include Dr. Isamu Akasaki, who will receive the Karl Ferdinand Braun Prize; Mr. Marc Baldo, who will be awarded the Jan Rajchman Prize; Mar-Apr Cover_SID Cover 3/22/2013 4:11 PM Page 1 contents Dr. Hoi-Sing Kwok, who will be awarded , OXIDE TFTs, AND DISPLAY WEEK PREVIEW ISSUE 2 Editorial: The Future Awaits and SID Can Be Your Guide! the Slottow–Owaki Prize; and Dr. Shigeo n By Stephen P. Atwood Mikoshiba, who will receive the Lewis & Beatrice Winner Award. 3 Industry News: Closes -TV Assembly Plant in Shanghai Mar./Apr. 2013 Official Monthly Publication of the Society for Information Display • www.informationdisplay.org Vol. 29, No. 2 n By Jenny Donelan 4 Guest Editorial: The Challenges and Opportunities of Large OLED TVs n By Ho-Kyoon Chung 6 2013 SID Honors and Awards This year’s winners of the Society for Information Display’s Honors and Awards include the Karl Ferdinand Braun Prize, the Jan Rajchman Prize, the Slottow–Owaki Prize, and the Lewis & Beatrice Winner Award. n By Jenny Donelan 12 Frontline Technology: RGB Color Patterning for AMOLED TVs RGB color patterning is one of the key technologies for manufacturing large-sized AMOLED TVs. Two competing approaches are currently being used to realize RGB subpixels. One requires a more difficult man- ufacturing process but has better color purity; the other is easier to manufacture but requires optimization in algorithms to overcome some weaknesses. n By Jang Hyuk Kwon Cover Design: Acapella Studios, Inc. 16 Frontline Technology: Oxide TFTs for AMOLED TVs AMOLED TVs using promising oxide semiconductors and thin-film transistors (TFTs) have been unveiled. This article will present the issues, challenges, and concerns of oxide TFTs for AMOLED TVs. In the Next Issue of n By Jin-Seong Park Information Display 20 Frontline Technology: Zinc-Oxynitride TFTs: Toward a New High-Mobility Low-Cost 3-D Trends and Display Week Thin-Film Semiconductor Demands for high-performance, low-cost, and low-energy-consumption displays continue to drive the devel- Show Review opment of new semiconductor materials. The success of the metal-oxide-semiconductor IGZO for display • Display Industry Awards backplanes has triggered even more activity, and zinc oxynitride is proposed as a possible solution. • Products on Display n By Yan Ye • Evaluating Color 26 Display Marketplace: AMOLED Production: Entering a New Era? • High-Frame-Rate Dual-Projector Active-matrix organic light-emitting-diode (AMOLED) displays have many attractive features that have led 3-D Debuts with The Hobbit companies to attempt to manufacture them, but one country – Korea – currently accounts for the vast majority of AMOLED-display manufacturing capacity. Ambitious investment plans in China, Japan, and • Creating 3-D Imagery with a Taiwan could change this balance over the next several years. Binocular Fusion Camera n By Paul Semenza • New Frontiers in 3-D Displays • Optical Dry Bonding 30 Enabling Technology: Flexing and Stretching So you work in displays? You may soon be working in flexible electronics too. Author Jason Heikenfeld, • AMOLED-Panel Market associate professor with the School of Electronic and Computing Systems at the University of Cincinnati, looks at several of the most interesting developments in flexible electronics. n By Jason C. Heikenfeld INFORMATION DISPLAY (ISSN 0362-0972) is published 6 times a year for the Society for Information Display by Palisades Convention 36 Show Review: Alpha and Omega: Most Exciting Display Technologies at CES Management, 411 Lafayette Street, 2nd Floor, New York, NY 10003; William Klein, President and CEO. EDITORIAL AND BUSINESS Giant TVs, ultra-high definition, IGZO, and more were among the display showstoppers at this year’s OFFICES: Jay Morreale, Editor-in-Chief, Palisades Convention Consumer Electronics Show in Las Vegas. Management, 411 Lafayette Street, 2nd Floor, New York, NY 10003; telephone 212/460-9700. Send manuscripts to the attention of the n By Steve Sechrist Editor, ID. SID HEADQUARTERS, for correspondence on sub- scriptions and membership: Society for Information Display, 1475 41 First Look: A Preview of the Events Scheduled for Display Week 2013 S. Bascom Ave., Ste. 114, Campbell, CA 95008; telephone 408/879- 3901, fax -3833. SUB SCRIPTIONS: Information Display is distributed Symposium Preview: Plan Ahead for the 2013 Symposium without charge to those qualified and to SID members as a benefit of 46 membership (annual dues $100.00). Subscriptions to others: U.S. & Make the most of Display Week 2013 with this advance look at this year’s technology sessions. Canada: $75.00 one year, $7.50 single copy; elsewhere: $100.00 one By Jenny Donelan year, $7.50 single copy. PRINTED by Wiley & Sons. PERMISSIONS: n Abstracting is permitted with credit to the source. Libraries are per- mitted to photocopy beyond the limits of the U.S. copyright law for 51 SID News: SID Bay Area Chapter Hosts a Glimpse into the Future of Displays private use of patrons, providing a fee of $2.00 per article is paid to the By Stephen Atwood Copyright Clearance Center, 21 Congress Street, Salem, MA 01970 n (reference serial code 0362-0972/13/$1.00 + $0.00). Instruc tors are permitted to photocopy isolated articles for noncommercial classroom 56 Sustaining Members use without fee. This permission does not apply to any special reports or lists published in this magazine. For other copying, reprint or 56 Index to Advertisers republication permission, write to Society for Information Display, 1475 S. Bascom Ave., Ste. 114, Campbell, CA 95008. Copy right © 2013 For Industry News, New Products, Current and Forthcoming Articles, see www.informationdisplay.org Society for Information Display. All rights reserved.

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Information editorial DISPLAY Executive Editor: Stephen P. Atwood The Future Awaits and SID Can Be Your 617/306-9729, [email protected] Guide Editor-in-Chief: Jay Morreale 212/46 0-9700, [email protected] by Stephen Atwood Managing Editor: Jenny Donelan Welcome to the March/April 2013 issue of Information 603/924-9628, [email protected] Display magazine. Last-minute preparations are well Advertising Sales Manager: under way for the 50th annual SID Display Week event in Joseph Tomaszewski Vancouver. With all the excitement around OLED technol- 201-748-8895, [email protected] ogy, we could not have predicted a better convergence of topics for this issue: OLED and Oxide-TFT technology, the Advertising Sales Representative: Roland Espinosa SID Symposium preview, and our cover story on the SID Honors & Awards recipients 201-748-6819, [email protected] for 2013. It’s one of the biggest issues we have ever produced and with our new bi-monthly schedule we wanted to make sure you had plenty to read between now and Editorial Advisory Board Display Week. Stephen P. Atwood, Chair As I worked on this issue and also attended some recent SID activities, it occurred Azonix Corp., U.S.A. to me that this may be the best time ever to be an SID member. Not only is there an Helge Seetzen amazing array of new technology innovations going on in our industry, but the oppor- TandemLaunch Technologies, Westmont, Quebec, Canada tunities to learn about those innovations through the resources available to members Allan Kmetz have never been better. For example, the SID on-line webinar program is now gaining Consultant, U.S.A. traction with almost a dozen recent additions covering topics such as 3-D stereoscopic Larry Weber displays, oxide TFTs, user interfaces (UIs), and the latest advances in LCD technology. Consultant, U.S.A. These presentations come from some of the most widely respected experts in the field and are available online only to SID members. Guest Editors Materials Also in this issue you can read about the recent San Francisco Bay Area chapter Bita, Qualcomm MEMS Technologies conference on display technologies for the future. These types of local programs are OLEDs loaded with presentations by the highest caliber of technology experts and are avail- Ho-Kyoon Chung, Sungkyunkwan University able to all SID members. They provide invaluable opportunities to make new contacts Oxide TFTs and leverage the knowledge base of the industry for your own company’s benefit. Arokia Nathan, University of Cambridge 3D Trends You can also read about the upcoming papers being presented at the SID Symposium Nikhil Balram, Ricoh Innovations as part of Display Week 2013. If you are not sure about becoming a member, plan on Touch and Interactivity coming to Vancouver and taking in the papers and exhibitions. Spend the next year Geoff Walker, Intel Corp. exploring what your new membership can do for you and I’m certain you will become e-Paper and Tablets a believer like me. Russel Martin, Qualcomm MEMS Technologies Lighting Our cover story this month is about the SID 2013 Honors and Awards, recognizing Sven Murano, Novaled AG the many achievements of those who have invested so much of their careers to further- Novel Displays ing the field of displays. As I have written previously, while the honors are being Brian Schowengerdt, University of Washington bestowed on them, the real honor is to those of us who have the privilege of knowing Very-High-Resolution Displays them, working with them, learning from them, and using their innovations to build David Trczinski, Avid Digital Signage better products that enrich people’s lives. Each year we do our best to capture their Terry Schmidt, Christie Digital Systems achievements in the biographies and citations thoughtfully compiled by our own Jenny Alan Koebel, Christie Digital Systems Donelan. But nothing we write can come close to documenting a lifetime’s worth of ideas, challenges, setbacks, inspirations, and successes that these individuals have Contributing Editors given to our industry. All I can say is that in those moments when you look at a great Alfred Poor, Consultant new product or technology, take a moment to reflect on all the human effort that has Steve Sechrist, Consultant Paul Semenza, NPD DisplaySearch probably gone into making the “overnight success” happen. Great innovation never Jason Heikenfeld, University of Cincinnati really happens overnight and so much of the technology that we take for granted today was built layer upon layer, almost like a brick wall, with each new advancement lever- The opinions expressed in editorials, columns, and aging the achievements of the previous level for its support. I’m sure you, as you read feature articles do not necessarily reflect the opinions of this story, will come away with something from the award recipients’ lives and work the Executive Editor or Publisher of Information Display you can relate to. Take the time to reach out to them and say “Congratulations and Magazine, nor do they necessarily reflect the position of the Society for Information Display. (continued on page 55)

2 Information Display 2/13 Industry News Issue2 p3_Layout 1 3/22/2013 3:11 PM Page 3

Architects of World Class industry news Display Enhancements

EuropTec USA is a specialist in glass processing and Panasonic Closes Plasma-TV fabrication for the display industry. As an expert in Assembly Plant in Shanghai various nishing and processing technologies, we

Earlier this year, news-media outlets including design and manufacture products for display The Wall Street Journal and The Japan Times applications. reported that Panasonic Corporation was closing its plasma-TV assembly plant in Shanghai, China. Panasonic media represen- PRODUCT & CAPABILITIES: tative Jim Reilly later confirmed this news t&BHMF&UDI®&BHMF&UDI1MVT™JOEVTUSZT with Information Display. The Shanghai CFTUQFSGPSNJOH"OUJ(MBSF(MBTT operations have been relocated to Panasonic AVC Networks Shandong Company, Ltd., an t&BHMF&UDI5PVHI"OUJ(MBSF"MVNJOPTJMJDBUF(MBTT existing LCD monitor-making facility in t"OUJ3FøFDUJWF(MBTT Shandong, China. “The plasma and LCD t7BOEBMQSPPGöMUFST operations will both be consolidated at that location,” said Reilly. t4JML4DSFFOJOH Panasonic’s move to streamline operations t$IFNJDBM4USFOHUIFOJOH is not surprising in the face of steadily declin- t)FBU5FNQFSJOH ing plasma-TV sales worldwide. “In the great t5FDIOJDBM1SPDFTTJOH$/$$VUUJOH &EHFXPSL scheme of things, it’s not that big of an impact,” says Paul Gagnon, Director of Global TV #FWFMJOH Research for NPD DisplaySearch. Gagnon believes the closure is more a reflection of APPLICATIONS: market conditions than a game changer for plasma. t5PVDI1BOFMT However, as has been the case for years, t"5.T,JPTLT reports of plasma’s demise are premature. t.JMJUBSZ"WJPOJDT Panasonic showed 16 new plasma TVs at CES 2013. The Shanghai plant that closed t3VHHFEJ[FE%JTQMBZTo$PNQVUFST  was assembling TVs rather than making the &RVJQNFOU .JMJUBSZ panels, says Gagnon, noting that Panasonic continues to manufacture PDPs in Japan. Panasonic is not actually the biggest producer of plasma TVs; that honor goes to , according to Gagnon. These two companies, plus LG, are the last manufacturers of plasma TVs in the world. – Jenny Donelan

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SID EXECUTIVE COMMITTEE President: President-Elect: Regional VP, Americas: Regional VP, Asia: Regional VP,B. Europe: Berkeley guest editorial Treasurer: A. Ghosh Secretary: D. Eccles Past President: B. Wang DIRECTORSJ. Rasp The Challenges and Opportunities of Large Y. S. Kim Bangalore: H. Seetzen OLED TVs Bay Area: M. Anandan Beijing: by Ho-Kyoon Chung Belarus: Canada: T. Ruckmongathen Dayton: J. Pollack OLED TVs were the talk of the Consumer Electronics DelawareX. Valley: Yan Detroit: V. A. Vyssotski Show in 2012, and this year’s CES featured attention- France: T. C. Schmidt getting OLED as well: 55-in. curved OLED TVs Hong Kong:D. G. Hopper India: J. W. Parker III from Samsung Display and LG Display and a 56-in. 4K Israel: J. Kanicki Japan: J-P. Parneix OLED TV from and Panasonic. These were impres- Korea: H. Leung sive demonstrations, and it was encouraging to see more players, such as Sony and Latin America:G. Rajeswaran Los Angeles:G. Golan Panasonic, coming into the game. However, there are customers anxiously waiting to Mid-Atlantic:K. Kondoh Mid-Europe:K.-W. Whang buy these TVs at affordable prices. And what happened to earlier promises that large New England: A. Mammana OLED TVs would be in production by the second half of 2012? Pacific Northwest:L. Tannas Russia: J. Kymissis It is difficult to tell exactly what’s happening at each company and what its future Singapore: H. De Smet Southwest: S. Atwood future plans are in terms of investment and production volume. Obviously, manufac- Taipei: A. Abileah turing challenges remain, especially for high yields. Another challenge is how, from a Texas: I. N. Kompanets U.K. & Ireland:X. W. Sun marketing perspective, to differentiate OLED TV from the LED-backlit LCD TV, Ukraine: S. O’Rourke Upper Mid-West: which has excellent picture quality and is becoming ever thinner. J. Chen Z. YanivCOMMITTEE CHAIRS S. Day Challenges of Manufacturing OLED TVs 50th Anniversary:V. Sergan Academic: B. Bahadur It is interesting to note that the two leading OLED-TV companies, Samsung Display Archives: and LG Display, have taken different approaches to TFT backplanes as well as to Audit: Bylaws: L. Tannas OLED RGB color patterning. The details of the technology are described in the Chapter FormationP. Bos – Europe: Conventions:R. Donofrio articles, “Oxide TFTs for AMOLED TVs” by Jin-Seong Park and “RGB Color ConventionsS. O’Rourke – Europe: Pattering in AMOLED TVs” by Jang Hyuk Kwon in this issue of Information Display. DefinitionsT. Lowe& Standards: Display Industry Awards: H. De Smet You may ask why each company chose their different path and which one will be Honors & Awards:P. Drzaic I-Zone: the winner. In my opinion, one company has chosen an approach that is an extension I. Sage Investment: T. Fiske of a well-established process for small-OLED mobile displays, and the other has Long-Range Planning: R. Melcher Membership: F. Luo chosen a cost-effective and relatively easy approach to manufacturing large OLED Nominating:J. Kanicki TVs – even though it has not been fully proven for mass production. It is probably too Publications:Y. S. Kim Senior Member Grade: A. Ghosh Web Site: H.-S. Kwok early to tell which one will be the eventual winner. Web Activities: However, considering the recent success of LED-backlit LCD TVs, the manufactur- A. Anandan H. CHAPTERSeetzen CHAIRS ing process for OLED TVs must meet the following requirements in order to compete A. Ghosh Bangalore:H. Seetzen with these incumbents. First, the cost of manufacturing must be lower than (or at least Bay Area: L. Palmateer Beijing: equivalent to) the cost of LCD TVs because most consumers will not pay a high Belarus: premium just for the sake of owning an OLED TV. In order to reduce the cost, the Canada: S. Sambadam Dayton: first priority of OLED R&D should be the development of processes and equipment G. Walker DelawareN. Valley: Xu that use the entire motherglass without cutting, from TFT to OLED fabrication. Detroit: A. Smirnov France: A. Kitai Second, the manufacturing process should be readily extendable to ultra-high- Hong Kong:J. C. Byrd resolution TVs. This requirement necessitates careful consideration when choosing India: J. Blake Israel: S. Palva the TFT-array technology and OLED color-patterning method. In order to drive as Japan: J. P. Parneix Korea: M. Wong many as 24 million subpixels for 4K TV; for example, not only the TFT but the metal- Latin America:S. Kaura lization process must be developed to meet the requirements. Also, the color pattern- Los Angeles:I. Ben David Mid-Atlantic:K. Kondo ing must have the scalability to handle the subpixel resolution down to ~100 µm in Mid-Europe:Y. S. Kim New England: V. Mammana large substrates, and the top emission structure needs to be developed for large OLED Pacific Northwest:P. Joujon-Roche panels. Russia: G. Melnik Singapore/Malaysia:H. J. Lemp Southwest: J. Gandhi Future Outlook of OLED TV Taipei: K. Yugawa Texas: V. Belyaev There is good news regarding OLED TV in that people now see the potential of large U.K. & Ireland: C. C. Chao Ukraine: OLED TV as the ultimate — something they want to have in their living M. Strnad Upper Mid-West:C. C. Wu room. As far as a consumer transition from LED-backlit LCDs to OLED TVs is SOCIETYR. Fink FOR INFORMATION DISPLAY M. Jones concerned, there are two schools of thought; it will be abrupt or gradual. Those who V. Sorokin (continued on page 55) P. Downen

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SID’s best and brightest

2013 SID Honors and Awards

This year’s winners of the Society for Information Display’s Honors and Awards include Dr. Isamu Akasaki, who will receive the Karl Ferdinand Braun Prize for his seminal contributions to the development of high-quality single-crystal GaN-based semiconductors and their PN-junction blue LEDs and lasers; Dr. Marc Baldo, who will receive the Jan Rajchman Prize for his outstanding contributions to the discovery of phosphorescent-OLED devices; Dr. Hoi-Sing Kwok, who will be awarded the Slottow-Owaki Prize for providing education and training in display technology to many students and professionals in the Asia region through the creation of a display research center; and Dr. Shigeo Mikoshiba, who will receive the Lewis & Beatrice Winner Award for his sustained exceptional contributions to SID for over 30 years.

by Jenny Donelan

HE RECIPIENTS of the Society for a spell after he built his first OLED in the lab. Awards Committee, grants these annual InformationT Display’s 2013 Honors and The deep red color of the OLED he made both awards based upon outstanding achievements Awards may be diverse in terms of the display surprised and entranced him. He continued to and significant contributions to the display technologies they pursue – GaN-based semi- focus on OLEDs and went on to contribute to industry. This year’s winners should take conductors, phosphorescent OLEDs, LCDs, the development of the first phosphorescent pride in this acknowledgment of their PDPs – and in geographical location – Japan, OLEDs. tremendous accomplishments. Massachusetts, Hong Kong – but they have at Slottow –Owaki Prize recipient Hoi-Sing least two things in common: vision and a clear Kwok and Lewis & Beatrice Winner Award sense of purpose. As a young researcher in recipient Shigeo Mikoshiba are both highly Tokyo, Isamu Akasaki became intrigued by respected scientists, but their awards from The 2013 award winners gallium nitride’s potential for blue-light emit- SID this year reflect their vision for education will be honored at the SID ters, despite the fact that the technology was and community-based efforts. Kwok saw the Honors & Awards Banquet, considered yesterday’s news by many scien- need for a display-based research center in tists — another promising piece of research Hong Kong and went on to create it, which which will take place Monday that had not worked out. Akasaki saw some- included raising the all-important funds. evening, May 20, 2013, during thing more in the material – specifically, he Mikoshiba, a busy educator and researcher, saw tiny, well-formed crystallites – but he recognized the importance of volunteering his Display Week at the Vancouver also saw that it might someday contribute to time to the display industry, and devoted many Convention Centre. display systems in a major way. After years efforts to the furthering of SID. His vision and of hard work, he, and the rest of the world, continued sense of purpose – he has volun- Tickets cost $75 and must be discovered he was right. teered continuously for more than 30 years — purchased in advance – tickets Another young researcher, Marc Baldo, raised up not only SID, but the industry as then a graduate student at Princeton, fell under a whole. Besides, as he told Information will not be available on-site. Display, such efforts are ultimately as enrich- Jenny Donelan is the Managing Editor of ing to the volunteer as to those he helps. Visit www.displayweek.org Information Display Magazine. She can be The SID Board of Directors, based on for more information. reached at [email protected]. recommendations made by the Honors &

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Said Akasaki, “I realized the great potential of GaN as a blue luminescent material when I found tiny yet high-quality crystallites embed- ded in HVPE-grown crystals containing many cracks and pits. I was intuitively convinced that conductivity control could be achieved if this kind of quality could be made over an entire wafer.” His eventual success with GaN-based semi- conductors ultimately contributed to display systems ranging from traffic lights to cell phones, to high-resolution TVs, digital signage, and more. “Akasaki transferred these basic technologies to industry and made fun- damental contributions to information-display technology,” says Yasushi Nanishi, a Professor at Seoul National University. It is one thing to pursue a brilliant idea, but it is another to pursue it and eventually suc- ceed after others have dismissed it. “That a Marc Baldo Dr. Isamu Akasaki single scientist’s determination and dedication overcame a barrier that researchers throughout OLEDs were fluorescent, but fluorescence Karl Ferdinand Braun Prize the world had become resigned to, and the harnesses only spin 0, or singlet, excitons. This award is presented for an outstanding impact of the multiple applications derived Since singlets represent only 25% of the total technical achievement in, or contribution to, from this achievement, make this a truly great number of excitons generated by electrical display technology. invention,” says colleague Maseo Ikeda. excitation, successful exploitation of the Dr. Isamu Akasaki, Professor at Meijo Akasaki received his undergraduate degree remaining 75% promised to increase OLED University, will receive the Karl Ferdinand from Kyoto University and doctoral degree efficiencies by a factor of 4. Braun Prize “for his seminal contributions to from Nagoya University. In 1952, he joined According to Russell Holmes, Associate the development of high-quality single-crystal Kobe Kogyo Corp. (now, , Ltd.). In Professor with the Department of Chemical GaN-based semiconductors and their PN- 1959, he moved to Nagoya University, where Engineering and Materials Science at the junction blue LEDs and lasers.” he worked as a research associate and an University of Minnesota, “This work by Marc In 1969, researchers succeeded in growing associate professor. In 1964, he became Head (and co-workers in the groups of Professors single-crystal gallium nitride on a sapphire of the Basic Research Laboratory IV and Stephen Forrest and Mark Thompson) permit- substrate. Two years later, the first blue LED General Manager of the Semiconductor ted an immediate quadrupling in the effi- with an MIS structure was created. These Department, both at MRIT. He returned to ciency of these devices by harvesting typically advances prompted excitement about the Nagoya University in 1981. Akasaki has dark triplet exciton states. This work, pub- development of GaN-based blue-light emit- authored and/or co-authored more than 700 lished in Nature in 1998, represented a key ters, but just several years later, most gallium- international journal/conference papers and enabling step for the development of an nitride researchers had withdrawn from the 30 book chapters and has been awarded 123 OLED-display industry and sparked an field. They could neither grow electronic- Japanese patents (including 110 patents explosion of research into highly efficient grade high-quality GaN single crystals nor related to group III nitrides) and 90 foreign phosphorescent emitters.” control their electrical conductivity. Both patents related to nitrides. The materials and structures Baldo worked features were key to the development of high- on were later commercialized by Universal performance blue-light emitters and high- Jan Rajchman Prize Display Corp. Phosphorescent materials are power high-speed transistors. This award is presented for an outstanding now found in many commercial products, About that time, an engineer named Isamu scientific or technical achievement in, or con- especially cell-phone displays. Akasaki, then working at Matsushita Research tribution to, research on flat-panel displays. Baldo received his bachelor of engineering Institute Tokyo (MRIT), became intrigued by Marc Baldo, SID member and Professor at degree from the University of Sydney and his GaN’s potential for use in blue-light emitters. the Massachusetts Institute of Technology, Ph.D. from Princeton University. When asked With the idea in mind that electronic devices will receive the Jan Rajchman Prize “for his what led him to his chosen field, he says, “I and the materials used to make them must outstanding contributions to the discovery of was very interested in the novelty of building be robust, he thought GaN could be the best phosphorescent-OLED devices.” devices based on molecules. I liked the idea candidate since it is very stable physically While a graduate student at Princeton, of designing materials and devices atom by and chemically, even though it was difficult Marc Baldo helped develop phosphorescent atom. I found that it was possible to make a to form high-quality crystals with it. OLEDs. Prior to this development, all device in an afternoon. It was an exciting

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SID’s best and brightest

time. When I built my first OLED, I remem- Dr. Hoi-Sing Kwok established the Center many noteworthy research results and training ber the shock of the beautiful deep red color. for Display Research (CDR) at the Hong numerous doctoral and postdoctoral students I was hooked.” Kong University of Science and Technology for work in the display industry. Kwok and OLEDs have been the “next big thing” for a in 1995. Many scientific institutions have a his students have also produced significant long time, and while each year brings progress specific program of research in semiconduc- intellectual properties in these research fields, in terms of commercial devices, that progress tors, he explains, but not many have programs obtaining 65 U.S. and Chinese patents thus has been slower than initially surmised by for displays. “Yet, displays are a large market far. many enthusiasts. Baldo says, “The challenge that is one-third to one-half that of semicon- “Professor Kwok is an anchor of the dis- for OLEDs has been that they are an entirely ductors,” he says. “There are a lot of opportu- play community in the Hong Kong, Taiwan, new technology, unlike any previous semicon- nities in display research.” Initially, Kwok and China regions,” says Ching Tang, Doris ductor device or display technology. Conse- was able to convince the government to Johns Cherry Professor of Chemical Engi- quently, the industry has not been able to draw provide about US$2 million to start CDR. neering at the University of Rochester. “He on many existing technologies. From the CDR has since evolved to become a center has contributed to a wide range of display devices themselves, to the packaging, to the of excellence in display research, generating technologies, from LCOS to OLED, and from manufacturing process, to the backplanes that drive the displays, everything has had to be developed specifically for OLEDs. Even today, with devices that are stable and effi- 2013 SID Fellow Awards cient, we are still working on the manufactur- The grade of fellow is conferred annually upon SID members of outstanding ing process. I think the advantages of OLEDs qualifications and experience as scientists or engineers whose significant contributions will make it all worthwhile, but it has been a to the field of information display have been widely recognized. lot of work. We still do not know all that is Hiroyuki Mori, “For his Takatoshi Tsujimura, possible with OLEDs.” significant contributions “For his contributions to to the development of the development of Slottow–Owaki Prize optical films for liquid- AMOLED displays and The Slottow–Owaki Prize is awarded for out- crystal displays including and OLED lighting.” standing contributions to the education and TN and OCB modes.” Mr. Tsujimura is General training of students and professionals in the Dr. Mori received his B.S. Manager and OLED field of information displays. and M.S. degrees in applied physics from Division Head for Konica Minolta, Inc. Dr. Hoi-Sing Kwok, SID fellow and the University of Tokyo and his Ph.D. from He has a degree from Tokyo University. Professor at Hong Kong University of Science the Liquid Crystal Institute at Kent State and Technology, will be awarded the Slottow– University. Owaki Prize, “for providing education and training in display technology to many students Kälil Käläntär, “For his Baoping Wang, “For his and professionals in the Asia region through many contributions to the many contributions to the the creation of a display research center.” science and technology of development of field- liquid-crystal-display emission displays and backlights, including light the shadow-mask plasma guides, optical micro- display panel.” reflectors, and light-shap- Dr. Wang is a Professor of ing devices. Dr. Käläntär is a senior scientist Electronics at Southeast University. He at Global Optical Solutions. He has Ph.Ds received his Ph.D. in electronic engineering in Optics from Toyohashi University of from Southeast University. Technology and Tohoku University.

Gopalan (Raj) Rajeswaran, “For his pioneering contributions to the development, manu- facture, and commercial- ization of AMOLED displays. Dr. Rajeswaran is Chief Executive Officer with Moser Baer Technologies. He earned his Ph.D. in elec- trical engineering from SUNY Buffalo. Dr. Hoi-Sing Kwok

8 Information Display 2/13 ID Donelan p6-10_Layout 1 3/22/2013 4:41 PM Page 9

creating new device architectures to advancing study and research under Prof. Kwok, espe- Lewis & Beatrice Winner Award display-manufacturing processes. The direct cially in learning how to think and to work The Lewis & Beatrice Winner Award for impact is that a large group of professionals of independently.” Distinguished Service is awarded to a Society diverse skills from his research group are now Throughout his professional career, Kwok member for exceptional and sustained service making their own contributions in both has supervised 42 Ph.D. dissertations, 20 to SID. academics and the display industries.” master’s theses, and 80 B.S. senior projects. Dr. Shigeo Mikoshiba, SID Life Fellow, Former student Dr. Haiying Chen of APT He has co-authored one book, “Photoalign- Jan Rajchman Prize winner, and Professor Electronics writes, “Fourteen years ago, I ment of Liquid Crystalline Materials: Physics Emeritus at The University of Electro-Com- joined Prof. Kwok’s group as a Ph.D candi- and Applications (Wiley/SID series),” and munications in Tokyo, Japan, will receive the date. That was a big challenge for me, a grad- over 380 journal papers Lewis & Beatrice Winner Award “for his uate with materials science and engineering His greatest satisfaction as a teacher? “To sustained exceptional contributions to SID background only. Prof. Kwok was very nice see the students grow and contribute to the for over 30 years.” and patient. He gave me enough space and industry. And sometimes to see them becom- Dr. Shigeo Mikoshiba is a life-long freedom to learn, to think, to plan, and to try. ing more knowledgeable than I and teaching researcher, educator, and gifted scientist who I benefited quite a lot during the four-year me back.” received SID’s Jan Rajchman Prize in 2007

2013 SID Special Recognition Awards Presented to members of the technical, scientific, and business community (not necessarily SID members) for distinguished and valued contributions to the information-display field.

Keiji Ishii, “For outstanding contributions to the Qun (Frank) Yan, “For the development of the development of the 145-in.-diagonal super-high- calcium-magnesium-oxide protective layer for vision (8K x 4K) plasma display panel.” Mr. Ishii high-luminous-efficacy plasma display panels.” is a Senior Research Engineer with the Display & Dr. Yan is Chief Scientist of the plasma display Functional Devices Research Division, Science & panel (PDP) business unit within Changhong Technology Research Laboratories, at Japan Electronics Group. He holds a Ph.D. in physics Broadcasting Corporation (NHK). He received from Vanderbilt University. his B. E. and M. E. degrees in electrical engineering from Saga University.

Ryuichi Murai, “For outstanding contributions to Takehiro Zukawa, “For the development of the the development of the 145-in.-diagonal super-high- calcium-magnesium-oxide protective layer for vision (8K x 4K) plasma display panel.” Mr. Murai high-luminous-efficacy plasma display panels.” is a researcher at Panasonic Corp. He received his Mr. Zukawa is a Staff Engineer with Panasonic B.E. and M.E. degrees in electronic engineering Plasma Display Corp., Ltd. He received his M.S. from Osaka University. degree in engineering from Toyama University.

In-Byeong Kang, “For his leading contribu- tions to the development of manufacturable film- patterned-retarder 3D displays and in-plane- Hidefumi Yoshida, “For his significant contribu- switching-based liquid-crystal panels.” Dr. Kang tions to the science and technology of liquid- is Senior Vice President and Head of the LG crystal displays, including the multi-domain Display Laboratory at LG Display Co. He earned vertical-alignment mode.” Dr. Yoshida is a Chief his Ph.D. in electronic engineering from the Technical Research Fellow with Sharp Corp. University of South Australia. He has a Ph.D. in engineering from Tokyo Institute of Technology. Isao Kawahara, “For his contributions to the research and development of the moving- picture-resolution metric for display panels.” Mr. Kawahara has retired as a senior manager for image quality at Panasonic Corp. He received his M.E. degree in electric engineering from Kyoto University.

Information Display 2/13 9 ID Donelan p6-10_Layout 1 3/22/2013 4:41 PM Page 10

SID’s best and brightest

obligations). “Nevertheless, I enjoyed my Mikoshiba earned his bachelor’s and mas- volunteer activities very much,” he says. ter’s degrees in plasma physics at the Tokyo Through these volunteer activities, Mikoshiba Institute of Technology. His doctoral degree, says he got to know many people who were also in plasma physics, is from the University helpful not only in terms of those activities of Alberta. Mikoshiba says he became inter- but for his research work. Last but not least, ested in display technology while working for volunteer work enriches one’s personality, starting in 1973, at about the time that says Mikoshiba. PDPs, LCDs, and FEDs were all emerging. n

Multi-Touchouch PrTMulti- Projectedojected CapacitivCapacitivee TTouchouch ScrScreenseens

Come visit us at Display Week 2013, BOOTH 309 o

Dr. Shigeo Mikoshiba .c

for contributions to PDP and LCD backlight- ing technology. Yet he has also through the years found time to serve and promote the

Society for Information Display. He joined wa SID in 1975, and since 1981 has continuously served SID, its Japan Chapter, Japan Display, aw and IDW. He has been President and Secre- tary of SID, as well as chair and member of dawar.com d countless committees. He has also served as an associate editor for both the Journal of the SID and Information Display. Sensor manufacturingmanufacturing in the USAUS ata Dawar’sDaA s PittsburghPittsbur’arwt Pittsbur facilityfacilitygh “I have known and worked with Prof. Mikoshiba for a great many years,” says SID Full U.S.U.S. based engineering support member Alan Sobel. “He has worked tire- Rugged Design - All glassglas constructionconss truction thattha providesprot vides ≥ 9H pencil lessly and indefatigably for SID in a number hardnessdneshar s and superior optics of capacities.” EnhancedEnhanced Sensitivity - Light touchtouch forfor effortlesseffortless input with finger,finger, Mikoshiba says it has not always been easy glovee or conductivecvglo onductiv stylusstyluse tylus to find the time to volunteer, especially while balancing university research, education, and GestureturGes e Capability - pinch, flick, tap,tap, click and rotater etota e administrative duties (not to mention family StandardtandarS d ProductProduct - ControllerController BoardBoard solutions fromfrom 4.3"W - 24"W24"W - Chip on FlexFlex solutions fromfrom 4.3"W - 17" CustomizationomizatCus tion - DecorativeDec aor e frtiva frontont lens availablea ailable forfv or tablet PC look The Society for Information SystemtsyS em tuning ata Dawar'sDawt ar's PittsburghPittsbur facilityfacilitygh Display is indebted to the following companies, who each donated $2000 to sponsor a prize:

Braun Prize AU Optronics Corp.

Rajchman Prize Sharp Corp. AMERICAN MADE

Slottow-Owaki Prize Fujitsu, Ltd., and 10101616 NORNORTHTH LINCLINCOLNOLN AVEAVE PITTSBURGH,PITTSBURGH, PAPA 1515233233 Dr. Tsutae Shinoda PH: 1.8001.800.366.1904.366.1904 / 4412.322.990012.322.9900 E: [email protected]@D WA OMCAR.

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RGB Color Patterning for AMOLED TVs

RGB color patterning is one of the key technologies for manufacturing large-sized AMOLED TVs. Two competing approaches are currently being used to realize RGB subpixels. One requires a more difficult manufacturing process but has better color purity; the other is easier to manufacture but requires optimization in algorithms to overcome some weaknesses.

by Jang Hyuk Kwon

Substrate LL COLOR TVs sold today realize Metal Acolor images through combinations of that, in turn, consist of RGB subpixels. Shadow Liquid-crystal-display (LCD) TV uses back- Mask lighting as the light source and color filters for the RGB subpixels, which are patterned by photolithography or ink-jet printing. Since organic light-emitting diodes (OLEDs) are self-emissive, we can realize RGB subpixels by direct deposition of RGB emission materials for each subpixel (RGB side-by-side) or by filtering white-OLED light through RGB color filters (WOLED + CF). Currently, there is much debate with regard to which approach will be the winner in the large-sized OLED-TV market. This article describes the pros and cons of each technology and presents an outlook for future OLED technology development. Source RGB Side-by-Side Patterning by Current Status Currently, the active-matrix organic light- Items emitting-diode (AMOLED) pixels for mobile (generation 3.5 evaporator) applications are manufactured by evaporation Shadow Effect < 5µm of small-molecule light-emitting materials -Pixel Align through metal shadow masks. When one- Pixel Pitch Variation ± ~10µm color material is being deposited, the other Margin: ± 15µm color areas are blocked by this mask. Figure 1 Total Pitch Variation ± ~5µm schematically shows the shadow-mask technology for red, green, and blue pixel µ patterning of . Alignment Accuracy < ±5 m

Jang Hyuk Kwon is with the Department of Information Display, Kyung Hee University, Fig. 1: A typical shadow-mask technology for pixel patterning shows green and blue pixels Seoul, Korea. He can be reached at jhkwon@ being blocked. The table at bottom shows the dimensional capability of the shadow-mask khu.ac.kr. process to date.

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Current shadow-mask technology is already larger substrates (such as Gen 8 and above) cules have a multilayer structure with two or mature and does not present any serious diffi- and higher resolution [ultra-definition (UD) more emitting layers in a simple stack or culties when used on substrates up to 750 mm and above], which are both necessary for tandem OLED structure. × 650 mm (which represents ¼ of a Gen 5.5 next-generation TVs. To be more specific, Figure 3 shows several structures devel- substrate of 1500 mm × 1300 mm). However, any misalignment will result in color mixing oped to realize white-OLED devices. Among this technology cannot be used for Gen 8 sub- and non-uniformity of the subpixels. Mask these, the tandem OLED structure has merits strates for AMOLED-TV production because window variation with multiple patterning in terms of longer lifetime and higher effi- glass and mask sagging become critical issues. processes can also be a serious problem for ciency; however, the manufacturing process is A new process technology called Small real mass production. Further technology a bit more complicated. The tandem device Mask Scanning (SMS) has been developed by development is needed in order to increase with two emissive layers as shown in Fig. 3 Samsung for large-area TV manufacturing. In manufacturing yield as well as to improve can greatly reduce current level to achieve the order to circumvent the sagging problem of scalability in substrate size and high resolution. required brightness value of each pixel and the substrate and the mask, the glass substrate more than doubling lifetime. The tandem is moved during pixel deposition while both White OLEDs with Color Filters device can also easily achieve very high effi- the small-area shadow masks and the linear The approach of white OLEDs with color ciency because both efficiency values of each evaporation sources are kept stationary (see filters (WOLED + CF) has received a great single cell are combined.1 In the beginning of Fig. 2). The merits of the SMS process are deal of attention because of its simpler process 2013, LG Electronics announced commercial (1) practically, the same small-molecule and attendant benefit of using the existing production of 55-in. AMOLED displays that materials used for mobile application can be color-filter infrastructure.1 This method can use the tandem WOLED + CF approach. used for TVs, and therefore good synergy easily overcome the inherent complexity of (In the CES Review in this issue of ID, author exists between the two applications, and (2) RGB side-by-side patterning with the shadow Steve Sechrist notes that LG planned to begin the benefits of low power and long lifetime masks. White emission can be achieved by shipping these units in Korea in February of and the color purity of the RGB side-by-side mixing three primary colors (red, green, and 2013.) pixel configuration are maintained. blue) or two complementary colors (yellow One problem with the WOLED + CF One major drawback is that achieving and blue) in the emissive layers. Generally, approach is that light-output efficiency is pattern accuracy becomes more difficult for WOLEDs consisting of small organic mole- reduced to 30% of the efficiency of RGB side-

RGB (SMS): Samsung Display WOLED: LG Display

Pixel Emitting Layer Color Structure Filter

RGB W-RGBW

Chuck Glass Glass Scanning Process Glass Method Mask Open Mask Linear Source Source Low Power & Long Lifetime Easy Process with > Gen. 8 Glass Merits Relatively Good Viewing Angle High Resolution Relatively Difficult Process High Power Consumption Demerits Color Mixing Issue Viewing Angle Issue Thickness Uniformity Short Lifetime

Fig. 2: The OLED RGB process using SMS (left) is compared with the WOLED + CF process (right) in terms of pixel structure, methodology, and pros and cons.

Information Display 2/13 13 Kwon p12-15_Layout 1 3/22/2013 5:32 PM Page 14

frontline technology

Structure Color Single EML Multiple EML Tandem Items conversion Efficiency Lifetime Process : Best, : Good, : Normal, : Bad

Cathode Cathode Cathode Cathode ETL ETL ETL ETL Blue Blue EML Emissive Blue EML Blue EML HTL HIL Unit Single EML HTL Yellow EML Charge Generation Layer HIL ETL HTL Yellow HTL Anode R + G EML HIL HIL Emissive Glass HTL Unit Anode Anode HIL Yellow Anode Glass Glass Glass

Fig. 3: Above are shown the merits and demerits of various WOLED structures (EML = emissive layer).

by-side because of the light absorption induced Future Prospects in Color Patterning thermal deposition of the entire active area by the color-filter pigments. This problem can Several companies are trying to develop alter- with an open mask after the solution printing be minimized if the RGBW four-pixel color native technologies to replace the current of red and green subpixels is being developed system is employed. Theoretically, the RGBW shadow-mask process used for large-area TV to overcome these lifetime issues. Recently, system can have about ~50% light output due applications. Solution-process printing tech- significant progress has been made in the to the mixing of white colors for bright images nologies such as ink-jet printing3 and nozzle development of soluble materials and the 2 and thereby compensate this for the light loss. printing4,5 have been proposed as pixel- process for AMOLED fabrication. Hence, it However, there is a trade-off between the reduc- patterning methods. These processes will is expected that solution printing processes tion of power consumption and the degradation be the ultimate objective for pixel-patterning will be available in the near future. of color purity. More circuitry to drive the methods for AMOLED displays since using Laser-printing technologies have also been white pixel is needed and light output effi- them is fairly simple and does not require any proposed as pixel-patterning methods, suitable ciency to each RGB subpixel depends on the vacuum equipment. for large-area displays. Laser-induced 6 white spectrum of WOLEDs. Therefore, the Several material companies are developing thermal-imaging (LITI) technology was first light output efficiency of actual displays may soluble materials for these solution processes. reported by Samsung. This technology uses not reach this ~50% theoretical level. Another However, it is not an easy task to develop donor films with a laser-light-absorbing layer issue lies in the color variation on viewing good soluble materials because OLED life- and a transfer organic layer. Laser light is angle because thick organic layers in the tan- time is very sensitive to impurities, film quality, converted into thermal energy as it shines dem structure result in several possible optical and environmental conditions. (One such on the light-absorbing layer. Subsequently, paths, which can distort color. Overall, a possible solution is discussed in the Industry the transfer layer melts and transfers to the more than two-times-higher power consump- News story, “Merck to Use Epson Ink Tech- substrate. The company is focusing on this tion and a much shorter lifetime can be a real nology for Large OLED Displays,” in the method only for small-sized high-resolution concern in AMOLED TVs using the WOLED January/February issue.) Among the RGB display applications. This process is very + CF system. However, a combination of materials, blue has the shortest relative life- sensitive to particles because any contami- new OLED materials and optimum color-ren- time. Device lifetimes of red and green OLED nated particles can fix onto the substrate dering algorithms may be able to solve the devices with solution printing processes are during the transfer process. Small-sized lifetime, power consumption, and color char- sufficiently extended to be of practical use. applications are better with regard to minimiz- acteristics issues, as discussed in Ref. 2. Consequently, a process involving blue ing yield loss.

14 Information Display 2/13 Kwon p12-15_Layout 1 3/22/2013 5:33 PM Page 15

Laser-induced pattern-wise sublimation 5M. O’Regan, IMID/IDMC/ASIA Display ’08 Technical Papers 35, 1008 (2004). (LIPS) technology7 has also been reported as Digest, 27 (2008). 7T. Hirano, K. Matsuo, K. Kohinata, an alternative to LITI technology. Both tech- 6S. T. Lee, J. Y. Lee, M. H. Kim, M. C. Suh, K. Hanawa, T. Matsumi, E. Matsuda, nologies are fundamentally very different. In T. M. Kang, Y. J. Choi, J. Y. Park, R. Matsuura, T. Ishibashi, A. Yoshida, and LIPS technology, emissive organic layers on J. H. Kwon, H. K. Chung, J. Baetzold, T. Sasaoka, SID Symposium Digest of the light-absorbing metal layer are deposited E. Bellmann, V. Savvateev, M. Wolk, and Technical Papers 38, 1592 (2007). n on glass and then attached to two substrates, S. Webster, SID Symposium Digest of one organic deposited substrate and one active-matrix backplane under vacuum. Finally, a laser scans the organic layer to form a pattern through sublimation transfer from NEED HELP WITH the organic layer to the active-matrix back- plane. Sony reported this process and demon- strated a 25-in. AMOLED panel at Display YOUR DISPLAY SOLUTION? Week 2007. In this process, similar thermal evaporation temperatures for host and dopant molecules are required. Patterning of phos- phorescent materials using this methodology is difficult because phosphorescent materials have much higher evaporation temperatures originated by high molecular weights. To date, no additional progress has been shown with this process.

Refinements Needed for Progress in Both Processes Currently, the two main patterning processes, SMS and WOLED + CF, are being intensively developed for commercialization. Gen 8 lines for both technologies have been already invested in for the production evaluation of 55-in. AMOLED-TV applications. Both tech- nologies are rapidly improving. Additional possible processes such as solution printing and LIPS are also being investigated. In the near future, significant progress in solution printing processes in particular is expected.

References Embedded Computer Systems /ŶĚƵƐƚƌŝĂů>͛ƐĨƌŽŵϭ͟ƚŽϭϬϮ͟ 1C.-W. Han, K.-M. Kim, S.-J. Bae, H.-S. Choi, J.-M. Lee, T.-S. Kim, Y.- H. Tak, Touch Screen Solutions Optical Enhancements S.-Y. Cha, and B.-C. Ahn, SID Symposium Digest of Technical Papers 43, 279 (2012). Custom Enclosures LED Backlight / Driver Design 2J. P. Spindler, T. K. Hatwar, M. E. Miller, A. D. Arnold, M. J. Murdoch, P. J. Kane, J. E. Ludwicki, and S. A. Van Slyke, SID EXPERIENCE MATTERS! Symposium Digest of Technical Papers 36, PROVIDING DISPLAY SOLUTIONS FOR OVER FIFTEEN YEARS 36 (2005). 3D. Lee, J. Chung, J. Rhee, J. Wang, S. Hong, B. Choi, S. Cha, N. Kim, K. Chung, H. Gregory, P. Lyon, C. Creighton, J. Carter, AS-9100 Registered ISO-9001 Registered M. Hatcher, O. Bassett, M. Richardson, and P. Jerram, SID Symposium Digest of Technical Papers 36, 527 (2005). 4W. F. Feehery, SID Symposium Digest of www.jacodisplays.com Technical Papers 38, 1834 (2007). 877.FPD.JACO / 877.373.5226 e-mail: [email protected]

Information Display 2/13 15 ID Park p16-19_Layout 1 3/22/2013 5:48 PM Page 16

frontline technology

Oxide TFTs for AMOLED TVs

AMOLED TVs using promising oxide semiconductor and thin-film transistors (TFTs) have been unveiled. This article will present the issues, challenges, and concerns of oxide TFTs for AMOLED TVs.

by Jin-Seong Park

INCE flexible and transparent amorphous parency: > 80% at visible range and carrier ate at relatively high speed and high current SIn-Ga-ZnO (indium gallium zinc oxide or concentrations of 1018/cm3. Interestingly, within small pixel dimensions. IGZO) thin-film transistors (TFTs) were those materials have been reported to have For large-sized AMOLED TVs, the mobility reported in 20041, tremendous progress has good semiconducting behavior under a range requirement is generally predicted to be over taken place with regard to amorphous-oxide of deposition parameters, doping elements, 30 cm2/V-sec, depending on semiconductor devices as TFT backplanes. and post-annealing processes. The amorphous and pixel-circuit designs, because OLED These devices enable high-performance flat- structure in the oxide semiconductor is also pixels need high current in order to emit light panel displays (FPDs), including active- important in avoiding the problems of carrier through electrical current injection. Many matrix organic light-emitting-diode displays trapping and low mobility caused by a poly- researchers have reported various oxide- (AMOLEDs).2 Many FPD manufacturers crystalline structure. The key property that semiconductor materials and structures that such as Samsung, LG, Sharp, and AUO have enables the formation of an amorphous struc- can achieve high-mobility TFTs. Interestingly already announced significant investment in ture is “crystal frustration” – i.e., the three enough, as we learn about the electronic large-sized AMOLED panel production based materials (In, Sn, and Zn) all tend to form nature of oxide semiconductors, we find on oxide-semiconductor devices in 2012. different crystal structures on their own, so the mobility may be controllable in the Although small-sized AMOLEDs for cell together will not permit the formation of poly- 1–30 cm2/V-sec range, as long as the device phones using low-temperature polysilicon crystalline structures. Thus, based on a instability is not a concern. Also, a few results (LTPS) TFTs are already in large-scale pro- number of papers and reports,2–4 amorphous- have been demonstrated with a mobility of duction at Samsung, it is quite significant to oxide-semiconductor TFTs combining In, Sn, almost 100 cm2/V-sec with a TFT as a unit hear announcements about adopting oxide- and/or Zn elements have generally exhibited cell, showing an indium tin oxide (ITO)/IGZO semiconductor devices as backplanes for reasonable field-effect mobility (µfe, greater or indium zinc oxide (IZO)/IGZO tandem larger-sized AMOLEDs. According to recent than 10 cm2/V-sec), a high on/off ratio for the active structure.5 press reports, LG Electronics will sell 55-in. drain current, and very low leakage current AMOLED TVs to consumers in the first quarter (less than 10 fA). Accordingly, amorphous- Robust Oxide TFTs of 2013 (see the CES review in this issue). oxide semiconductors may be considered the Instability is perhaps the most important issue For several decades, wide-bandgap oxide ultimate solution for producing large AMOLED that may block the practical application of materials, including ZnO, Al-doped ZnO, Ga- TV panels at low cost. oxide TFTs to AMOLED displays. Recent doped ZnO, SnO2, In2O3, InZnO, and InSnO, Many researchers and engineers still have efforts have been focused on understanding have been intensively investigated for sensor, concerns regarding certain critical device device instability and improving long-term optoelectronics, photovoltaic, and transparent- issues of oxide-semiconductor devices. These stability. To investigate the stability of oxide electrode applications due to their high trans- are required further improvements in mobility, TFTs, many researchers have considered four stability, pixel design, and electrodes. practical stress conditions: negative/positive Jin-Seong Park is a professor at Hanyang bias, temperature, illumination, and environ- University. His research focuses on oxide- The Need for High Mobility ment (humidity).6,7 Upon application of the semiconductor materials and devices, flexible High mobility, greater than 100 cm2/V-sec in four stresses, the oxide TFT generally only AMOLEDs, and thin-film encapsulations. LTPS TFTs, is very important for small-sized exhibits a Vth shift without a change in mobility, He can be reached at jsparklime@hanyang. AMOLED panels because the pixel-driving as shown in Fig. 1(a). This may occur by ac.kr. TFT and the embedded circuits need to oper- either charge trapping at the channel/gate-

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insulator interface or charge injection into the A Pixel-Circuit Design for Oxide TFTs switching transistor, the current-induced gate-dielectric bulk. Occasionally, it has been Besides the mobility and stability issues, there threshold-voltage shift should be seriously observed that the devices spontaneously is another problem to solve in order to realize considered for AMOLED driving transistors. recover their initial state after a relaxation large-sized AMOLED panels: the pixel-circuit It has been reported that a Vth shift of the driv- period without any thermal annealing. design. It is well known that the use of oxide ing transistor by 0.1 V induces variations in It is also critical to accelerate the Vth shift by TFTs can result in an AMOLED panel with the resulting luminance of the OLED pixels 8 applying two stress conditions simultaneously. the simplest pixel circuit, as shown in Fig. 1(c), by approximately 20%, which reflects the fact Although several groups have reported possi- because of the amorphous nature of the mate- that the brightness of each pixel strongly 14 bilities such as oxygen vacancy, hole trapping, rials and the resulting highly uniform electri- depends on the drain current. Therefore, and injection, the origin of the degra- cal properties. If the TFTs are uniform (long OLED displays should employ complex dation mechanism is still under investigation. range and short range) and stable (bias stress), compensation circuits that have four or more In order to improve the stability of oxide a simple circuit structure is the only thing that TFTs, such as 4T2C, 5T2C, and 6T2C circuits, TFTs, researchers have taken steps including is needed. If the TFTs are non-uniform and with 4T2C meaning that the circuit involves optimized structure,9 suitable gate-insulator unstable, non-uniform OLED luminance may four transistors and two capacitors.3 In addi- materials,10 impermeable passivation layers,11 occur due to the different parameters of the tion, an oxide semiconductor exhibits n-type- robust semiconductors,12 and post-annealing switching TFT on each pixel. These problems like properties, indicating that the major treatments.13 By comparing bottom-gate can be fixed by using circuit-design technolo- carrier in a channel is an electron. In an aver- TFTs with a back-channel-etch (BCE) or an gies such as a compensated circuit (5T+2C, age OLED pixel circuit, a compensation etch-stopper (ES) structure [Fig. 1 (b)], etc.) . Grain boundaries and device instability circuit such as that shown in Fig. 2 should be researchers showed that the stability of an are important factors to consider in regard to employed in order to utilize n-type oxide ES-type device was superior to that of a BCE- non-uniformity. When AMOLEDs based on TFTs, unlike the case for p-type LTPS TFTs, type device, which may be attributable to the oxide TFTs are demonstrated, the oxide TFTs where this is not required. formation of defective interfacial layers. For should exhibit no significant variation in Vth gate insulators, the superior stability of the and µfe during prolonged operation. Low-Resistivity Electrodes SiOx or AlOx gated devices can be attributed Unfortunately, as mentioned above, the Regarding large-sized AMOLED panels, the to the suppression of hole injection or trap- degradation of oxide TFTs is unavoidable proper material for gate, source, and drain ping in the gate dielectric, owing to relatively under stress conditions. While the variation electrodes must be chosen. Large, high- large valence-band offset and less hydrogen of µfe and Vth is less important in an AMOLED resolution, and fast-frame-rate panels require content. In addition, low-permeable passiva- tions such as AlOx and SiONx exhibited better stability in devices under stress conditions. In oxide semiconductors, robust oxide TFTs have a higher oxygen content in the active layers during the deposition process and post- treatment. In general, in terms of materials and structures, robust oxide TFTs had less hydrogen and higher oxygen compositions to suppress a Vth shift under four practical stress conditions. It is very difficult to design oxide-TFT structures with a selection of proper materials based on large-sized mass-production equip- ment. Therefore, it may be impossible to fabricate perfect and stable oxide TFTs by using conventional processes, structures, and equipment because the electronic conduction mechanism in oxide semiconductors depends on controlling defect systems such as oxygen vacancy and hydrogen incorporation, as well as cation composition. TFT structures are very well suited to existing a-Si TFT produc- tion lines, but various process factors still need to be closely considered. Making stable Fig. 1: (a) Gate-voltage vs. drain-current chart represents the evolution of a transfer curve as a oxide TFTs that perform well in the final function of bias-temperature-illumination stress. (b) The schematics of etch-stopper (ES) and application requires very tight control of the back-channel-etch (BCE) structures are illustrated. (c) This conventional pixel design for an processes, materials, and equipment. AMOLED panel uses two transistors and one capacitor.

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ties because the ES layer can prevent the DATA[m] ELVDD DATA ANODE degradation of active layers during the follow- G1 ing dry- or wet-etch process. The ES process G2 SCAN[n] G3 in oxide TFTs is the contradictory factor with V0 T2 regard to fabrication cost and production T1 yield. Thus, Sharp and LG Display have SCAN[n+3] demonstrated mass-produced AMLCD and T5 DrTr C1 AMOLED backplanes with ES-type structures to guarantee the quality of the panels with EMB[n]] C uniform device performance. However, these T4 C2 companies have intensively developed a VREF process with fewer mask steps (e.g., a BCE- OLED type structure), resulting in a high-selective T3 wet-etchant and self-passivation layer. To CATHODE VINIT balance fabrication cost and yield in large- ELVSS sized AMOLED displays, a BCE-type device may be an inevitable selection. While the (a) 5 Transistors + 2 Capacitors (b) 5 Transistors + 1 Capacitor [15] [16] high-quality gate-insulator process may dete- By Samsung Display By Sharp and SEL riorate the uniformity and performance of devices by damaging the active layer, a top- gate device configuration can be a possible Fig. 2: This circuit diagram of a pixel (AMOLED panel based on a-IGZO TFTs) shows exam- solution in reducing the number of masks ples from (a) Samsung Display and (b) Sharp and Semiconductor Energy Laboratory (SEL). and parasitic capacitance for large-sized AMOLEDs. electrodes with low resistivity, such as Al and display (AMLCD) TV panels based on a-Si:H Cu. However, Al has poor adhesion and TFTs. Oxide TFT: A Solution Awaiting easily oxidizes during the AMOLED processes. To minimize the fabrication cost of an Solutions The Cu element easily diffuses and incorpo- active-matrix backplane, it is important to Since small-sized AMOLED displays have rates into the oxide semiconductor and gate reduce the number of photolithography masks. been successful in the display marketplace, insulator through thermal annealing and electro- Current a-Si:H LCDs employ 4–5 masks, there is no doubt that AMOLED displays have migration, as is well-known, while showing using a gray mask (also called a halftone the potential to become a superior display the degradation of electrical properties such as mask) to pattern the source/drain electrodes technology for TV. However, as far as the mobility and stability. Recently, AUO applied and the channel in a single mask step. backplane technology is concerned, it is not Ti/Al/Ti electrodes to 37-in. AMLCDs, and Samsung Display recently demonstrated yet clear which technology is suitable for Samsung Electronics applied Cu-based bus AMOLED displays based on oxide TFTs, large-sized AMOLEDs. Since 55-in. AMOLED lines to a 15-in. AMLCD.17,18 Also, LG employing seven masks with an ES structure.19 TV panels were first demonstrated in 2012, Display has adopted Cu-based electrodes in its As mentioned above, the ES-type device many manufacturers and researchers have 55-in. AMOLED-TV product. not only has superior stability, but also has struggled to realize solutions to the following excellent uniformity in the electrical proper- problems: mobility, stability, and yield. Oxide-TFT Prospects for AMOLED TVs From a market perspective, some observers in the display industry have deep concerns about Table 1: Shown is a comparison of AMOLED panel designs based on polysilicon, the competitiveness of AMOLED TV based amorphous silicon, and oxide TFTs. on oxide TFTs. As shown in Table 1, oxide semiconductors have promising possibilities; AMOLED Panel Poly-Si TFT a-Si:H TFT Oxide TFT these initially led to a great deal of attention. Semiconductor Poly-crystalline Si Amorphous Si Amorphous IGZO Phrases such as “low-cost-based AMOLED TFT uniformity Poor Good Good backplane technology” or “like amorphous- silicon (a-Si:H) TFT technology for Complex Complex Simple/Complex Pixel circuit AMOLEDs” were used to describe progress (5T + 2C etc.) (4T + 2C, 5T + 2C) (2T + 1C/6T + 2C) toward the commercialization of AMOLED Channel mobility ~100 cm2/V-sec 1 cm2/V-sec >10 cm2/V-sec TV panels. Today, many companies have struggled to reduce fabrication costs in order TFT type PMOS (CMOS) NMOS NMOS to compete not only with AMOLED TV TFT mask steps 5 ~ 11 4 ~ 5 5 ~7 panels based on LTPS TFTs, but also with high-quality active-matrix liquid-crystal- Cost/Yield High/Medium Low/No data Low/Medium

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Recently, some research groups have 15Y. G. Mo, M, Kim, C. K. Kang, J. H. Jeong, reported a c-axis-aligned IGZO layer as a Y. S. Park, C. G. Choi, H. D. Kim, and S. S. robust active layer, a large-sized (over Gen 8) Kim, SID Symposium Digest Tech Papers 40, sputtered target, and a high-mobility oxide 37 (2010). material such as InZnSnO. Although device 16T. Tanabe, S. Amano, H. Miyake, degradation and electronic-conduction mecha- A. Suzuki, R. Komatsu, J. Koyama, nisms have been investigated in oxide TFTs, S. Yamazaki, K. Okazaki, M. Katayama, interdisciplinary researches from theoretical H. Matsukizono, Y. Kanzaki, and T. Matsuo, J O I N S I D calculation to device engineering have SID Symposium Digest Tech. Papers 42, 88 We invite you to join SID to increased drastically in recent times. As we (2012). participate in shaping the future gain deeper understanding into oxide semi- 17M. C. Hung, et al., 2010 Intl. Workshop on development of: conductors and processes, they will no doubt TAOS, Tokyo, Japan. 18 • Display technologies and display- become the solution to realizing large-sized J. H. Lee, et al., SID Symposium Digest related products AMOLED TVs in the marketplace. Tech. Papers 40, 625 (2010). 19H. D. Kim, J. S. Park, Y. G. Mo, and • Materials and components for References S. S. Kim, 9th Intl. Meeting on Information displays and display applications 1 K. Nomura, H. Ohta, A. Takagi, T. Kamiya, Displays, 3-1 (2009). n • Manufacturing processes and M. Hirano and H. Hosono, Nature 432, 488 equipment (2004). 2J. S. Park, W. J. Maeng, H. S. Kim and J. S. Submit Your News Releases • New markets and applications Park, Thin Solid Films 520, 1679 (2012). Please send all press releases and new product announcements to: In every specialty you will find SID 3T. Kamiya, K. Nomura, and H. Hosono, Jenny Donelan members as leading contributors to Sci. Technol. Adv. Mater. 11, 044305 (2010). 4 Information Display Magazine their profession. J. K. Jeong, Semicond. Sci. Technol. 26, 411 Lafayette Street, Suite 201 034008 (2011). New York, NY 10003 5 http://www.sid.org/ S. I. Kim, C. J. Kim, J. C. Park, I. Song, Fax: 212.460.5460 S. W. Kim, H. Yin, E. Lee, J. C. Lee, and e-mail: [email protected] Membership.aspx Y. Park, IEEE Electron Device Meeting (IEDM 2008), 1 (2008). 6J. K. Jeong, H. W. Yang, J. H. Jeong, Y. G. Mo, and H. D. Kim, Appl. Phys. Lett. 93, 123508 (2008). 7J. H. Shin, J. S. Lee, C. S. Hwang, S. H. K. Park, W. S. Cheong, C. W. Byun, J. I. Lee, and H. Y. Chu, J. ETRI 31, 62 (2009). 8K. H. Lee, J. S. Jung, K. S. Son, J. S. Park, T. S. Kim, R. Choi, J. K. Jeong, J. Y. Kwon, B. Koo, and S. Lee, Appl. Phys. Lett. 95, 232106 (2009). 9J. Y. Kwon, K. S. Son, J. S. Jung, K. H. Lee, J. S. Park, T. S. Kim, K. H. Ji, R. Choi, J. L, Jeong, B. Koo, and S. Lee, Electrochem. Solid-State Lett. 13/6, H213 (2010). Display Week 2013 10J. S. Jung, K. S. Son, K. H. Lee, J. S. Park, T. S. Kim, J. Y. Kown, K. B. Chung, J. S. SID International Symposium, Park, B. Koo, and S. Lee, Appl. Phys. Lett. 96, 193506 (2010). Seminar & Exhibition 11S. I. Kim, S. W. Kim, C. J. Kim, and J. S. Park, J. Electrochem. Soc. 158 (2), H115 May 19–24, 2013 (2011). 12H. S. Kim, et al., Appl. Phys. Lett. 97, Vancouver Convention Center 102103 (2010). 13K. H. Ji, et al., Appl. Phys. Lett. 98, 103509 Vancouver, British Columbia, Canada (2011). 14H. J. In and O. K. Kwon, IEEE Electron Device Lett. 30, 377 (2009). www.displayweek.org ID Ye p20-24_Layout 1 3/22/2013 5:52 PM Page 20

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Zinc-Oxynitride TFTs: Toward a New High- Mobility Low-Cost Thin-Film Semiconductor

Demands for high-performance, low-cost, and low-energy-consumption displays continue to drive the development of new semiconductor materials. The success of the metal-oxide semiconductor IGZO for display backplanes has triggered even more activity, and zinc oxynitride is proposed as a possible solution.

by Yan Ye

2 HE CARRIER MOBILITY of a semi- TFT is below 1 cm /V-sec, the low cost of the However, because the cost to fabricate LTPS conductorT material, which is a measure of material and its TFT fabrication set a bench- TFTs is much higher than that for a-Si TFTs, how fast mobile or holes can move mark for cost-effective production. LTPS typ- LTPS is used today mostly for high-end small- in the material under an applied electric field, ically has a mobility of 50–150 cm2/V-sec. area display products. Recently, amorphous is a key parameter for determining the per- formance of an electronic device. For active- matrix thin-film-transistor (TFT) displays, 30 high mobility is related to high resolution,

high refresh rate, low energy consumption, -1 s

and high manufacturing yield. -1 IGZO: dep using Ar only

This article will look at the achievable V 2 performance of indium-gallium-zinc-oxide (IGZO) as well as that of other metal-oxide 20 semiconductor materials for TFT applications. Efforts to make IGZO TFTs prevalent in display manufacturing are still ongoing as are searches for even better semiconductor materials that will match the high perform- 10 ance of low-temperature polysilicon (LTPS) TFTs and the low cost of amorphous-silicon IGZO: dep using Ar and 2% O2

(a-Si) TFTs. Zinc oxynitride (ZnON) is cm Hall mobility, described here as one possible path to realiz- ing these performance and cost goals. Ref: Ye and Hussain, AKT internal, 2011 0 a-Si and LTPS No 350C 450C 550C a-Si is widely used as a TFT channel material. 650C Although the field-effect mobility of an a-Si annealing Annealing Condition Yan Ye has been working on the development of new technology at Applied Materials for more than 20 years. He can be reached at Fig. 1: The Hall mobility of a-IGZO films is shown before and after annealing at different [email protected]. temperatures.

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indium-gallium-zinc-oxide (a-IGZO), one of As shown in Fig. 2, the transition point at Multi-Metal Oxides the metal-oxide semiconductors developed in which the ionized impurity scattering mecha- The grain-boundary-limited transport problem the last decade, has been used to successfully nism becomes dominant is at a carrier concen- encountered in single-metal oxides can be 20 -3 make display backplanes with a mobility tration of ~10 cm in ZnO. It is worth addressed effectively by forming multi-metal higher than that of a-Si TFTs at a cost lower noting that in single-crystal Si, the transition oxides, as shown in Fig. 3(b). Since multiple than that of LTPS TFTs. point at which ionized impurity scattering metals are involved in forming the crystalline It is of interest to know whether the mobility becomes dominant compared to phonon structure of the film during deposition, under of an IGZO TFT can reach a level similar to scattering is at a carrier concentration of a balanced ratio, preferential growth of a 17 -3 that of an LTPS TFT through process optimiza- ~10 cm . crystalline structure from any metal used can tion. A wide range of measurements of the For other single-metal oxides, it is observed be interrupted by the presence of other metals. field-effect mobility of IGZO TFTs, which are that high mobility can be achieved at high a-IGZO, with a composition of about 1:1:1:4, extracted from I–V measurements, have been carrier concentration where the material is is a good example in this category. reported in the literature. Although TFT field- more like a conductor than a semiconductor. However, it is observed that even though effect mobility is a key parameter for validat- For example, In2O3:H films attain a mobility there is no clear grain boundary in a-IGZO, ing channel-layer performance, its intrinsic above 100 cm2/V-sec at a carrier concentra- electron transport is still limited by a potential limit is difficult to establish based on existent tion over ~1020 cm-3, characterizing as con- barrier just as it results from grain-boundary- data. In fact, accurate field-effect-mobility ductors. In fact, it is difficult to make a limited transport, showing an increase in assessment relies on precise measurements of single-metal oxide film with a high mobility mobility with an increase in carrier concentra- the I–V transfer curve, channel width and length, and a low carrier concentration as desired for tion [Fig. 3(d)]. The barrier remains the dom- capacitance, etc. It is sensitive to TFT fabrica- TFTs. Therefore, it is necessary to search for inant mechanism limiting the mobility at tion, measurement, calculation, and human error. other options. carrier concentrations up to ~1020 cm-3 with Hall mobility, the carrier mobility attained from Hall-effect measurement, is a more direct measurement of the material itself. 3 Therefore, Hall mobility is more suitable for 10 comparing different materials, although certain limitations or errors can also exist. Figure 1 plots the Hall mobility of amorphous- Grain-boundary scattering mG IGZO of a composition of about 1:1:1:4 -1

attained in a test. These data suggest that s mobility achieved by a-IGZO should be -1

higher than that of a-Si, but not LTPS. V 2

2 10 Single-Metal Oxides Several mechanisms limit electron or hole transport inside n- or p-type semiconductors. Single-metal oxides, such as ZnO, In2O3, and SnO2, have been studied intensively as trans- parent conductive oxides (TCOs) for decades m -1 m -1 -1 and as semiconductors for TFTs in the last 1 ( 1 + G ) decade. Figure 2 shows the Hall mobility at 10 different carrier concentrations for doped and Ionized impurity scattering m1 undoped ZnO films. It is clear that two mech- anisms limit carrier transport in the material: grain-boundary-limited transport and ionized cm Hall mobility, impurity scattering. ZnO is normally poly- Ref.: Minami, MRS Bulletin/August 2000 crystalline. The boundaries between the

crystalline grains can trap charges, deplete 0 the carriers around them, and interrupt the 10 19 20 21 22 electron transport across them, presenting 10 10 10 10 potential barriers with respect to the conduc- tion-band minimum [Fig. 3(a)]. The barrier -3 height decreases with increasing carrier con- Carrier concentration, cm centration until Coulombic ionized impurity scattering dominates as the mechanism- Fig. 2: Mechanisms limiting Hall mobility are shown based on the Hall-mobility measurement limiting electron-carrier transport. of various doped or undoped ZnO films at different carrier concentrations.

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no signs of Coulomb scattering or defect cations should be larger than that of cation conduction-band minimum that will give rise reduction taking over. Therefore, the mecha- sites. However, it may not occur everywhere to potential barriers. This model may also nism resulting in this barrier is strong. in reality. Even by excluding the complexity explain why mobility is reduced in a highly Notably, the mobility-carrier concentration of randomness in an amorphous phase, it may doped single-metal oxide, even though no relationship remains the same even for single- not be thermodynamically favorable to pack significant grain-boundary-limited transport is crystalline IGZO as shown in Fig. 3. A cations of different metals at an equal dis- present, and why a ternary compound such as percolation conduction model has been used tance, as described in the ideal case. In addi- IGO or IZO may result in a higher mobility as to explain the barrier. tion, different metals may interact with others reported due to less complexity than other Conceptually, the potential barrier in IGZO differently, making the interaction distance quaternary compounds. may also be explained based on the model of between cations from different metals more It is possible to achieve a higher mobility s-orbital wave-function overlap. In an ideal complicated. Therefore, it is very likely that by changing the composition of a multi-metal case for a multi-metal oxide, as illustrated for there will be some locations where the site oxide, i.e., making an IGZO with a different IGZO in Fig. 3(b), the distance of the interac- distance is larger than the interaction distance ratio. When making a film with an unbal- tion between s-orbitals of neighboring metal between cations, causing interruptions on the anced ratio, crystalline structures grow rela-

Ref.: Kamiya, et al, Sci. Tech Multi-metal oxide: Adv. Mater. 11 (2010)

InGaZnO, InSnZnO ... (Quaternary) -1 s

ZnSnO, InZnO, InWO, ... (Ternary) -1 V

2 10 Path 1 The film can be made as amorphous and HQ a-IGZO therefore the barrier from grain boundary can be eliminated. Single-metal oxide: However, a barrier due to multi-metal cations may exist to impede electron transport, ZnO, SnO2, In2O3, Ga2O3 resulting in a low mobility that is not expected.

Hall mobility, cm Hall mobility, c-IGZO1 Grain boundary LQ a-IGZO c-IGZO5 Ideal model for Possible model for 1 16 17 18 19 20 a-IGZO a-IGZO 10 10 10 10 10 Carrier concentration, cm-3

Barrier (3d) Ec

Ef Ev 100 Ref.: Ye, et al, J. Appl. ZaON-1 Ref.: Nomura, et al, Nature, 432, (2004). Phys. 106, (2009) ZaON-2 The binary compound is more likely ZaON-3 -1 in polycrystalline phase. In a film s -1

with a low carrier concentration (3b) V desired for TFT, a barrier resulting 2 Amorphous from grain boundary scattering IGZO films limits electron mobility. Single-metal oxynitride: 10 ZnON, ZnON:Al, ZnON:Sn, InON,. (3a) By utilizing O and N as anions, crystalline growth even with single-metal cations can be Hall mobility, cm Hall mobility, Path 2 suppressed. Therefore, the barriers due to Single-crystalline both grain boundary and multi-metal cations IGZO films 17 20 21 may be minimized, and high mobility can be 1016 10 1018 1019 10 10 attained. Carrier concentration, cm-3 (3c) (3e)

Fig. 3: The barrier resulting from grain boundary commonly encountered in a single-metal oxide (a) can be suppressed by forming either a multi-metal oxide (b) or a single-metal oxynitride (c). Data plotted in (d) show that the mobility of a-IGZO or c-IGZO increases as carrier con- centration increases, indicating that a potential barrier, similar to that due to grain-boundary-limited transport, exists. Data plotted in (e) show that several as-deposited ZnON films attained from a 50°C process follow a different trend compared with IGZO.

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tively easily if the defect level is kept low, and Fig. 3. Since both oxygen and nitrogen are Figure 4 shows films deposited at different thus barriers associated with grain-boundary- used as anions, which require different oxygen flow rates under a high nitrogen flow limited transport return. Besides, barriers crystalline structures in the compound, the rate of 500 or 300 sccm in a reactive sputter- associated with multi-metal cations still exist, arrangement of zinc cations in the film is ing process. When no oxygen gas is intro- just as in a ternary compound or a highly doped disordered. The film can be deposited duced and oxygen unintentionally remaining binary compound. Therefore, the improvement through a reactive sputtering process using a or is carried into the chamber is minimized, a in mobility thus far with a carrier concentra- metallic zinc target and reactant gases such as Zn3N2 film is produced. Zn3N2 film is poly- tion suitable for TFTs is limited. oxygen and nitrogen. Composition and crystalline as observed by X-ray diffraction crystalline structure of the film can be varied (XRD) and grazing-angle XRD (GXRD). Zinc Oxynitrides by controlling the competition of reactions When a small amount of oxygen gas is intro- The barriers resulting from both grain bound- between zinc and nitrogen and between zinc duced, the growth of the Zn3N2 crystalline ary and multi-metal cations can be suppressed and oxygen, which can be achieved by adjust- structure is interrupted because the reaction by forming a single-metal cation (Zn) and ing the flow rate ratio of oxygen and nitrogen between zinc and oxygen starts to compete multi-anion (O and N) metal oxynitride such along with the associated pressure, tempera- with the reaction between zinc and nitrogen. as zinc oxynitride (ZnON), as shown in ture, and power used in the process. For a flow rate of oxygen between 5 and 40

As-deposited film from a 50C process 50 500 sccm N2, Zn -1 300 sccm N2, Zn n-type semiconductor s 500 sccm N2, Zn:Al -1 300 sccm N2, Zn:Al

V 40 2 30

20

10 Hall Mobility, cm Hall Mobility, 0

0 10 20 30 40 50

O2 flow rate, sccm

Zn3N2 ZnON ZnO:N ZnO 4000 32 800 4000 16000 101 101 400 0 sccm O2, 500 sccm N2 20 sccm O2, 500 sccm N2 50 sccm O2, 500 sccm N2 XRD XRD XRD XRD 180C, 50 sccm O2, 100 sccm N2 3000 600 3000 440 332 ...... Zn3N2 (cubic) ...... ZnO (hex) 12000 .... ZnO (hex) 100

2000 400 2000 8000 100 002 721 002 110 103 110

1000 222 103 444 1000

521 200 112 631 611 102 4000 112 102

0 0 0 0 8000 32 800 8000 8000 101 101 400 ... . Zn3N2 (cubic) GXRD GXRD GXRD 600 .... ZnO (hex) .... . ZnO (hex) 6000 440 6000 6000 332 100 4000 400 4000 4000 100 002 002 721 110 Intensity Intensity 222 103 110 103

2000 444 521 200 631 611 2000

112 2000 102 112 102

0 0 0 0 30 40 50 60 70 30 40 50 60 70 30 40 50 60 70 20 30 40 50 60 70 80 q q Diffraction angle 2 Diffraction angle 2 Diffraction angle 2q Diffraction angle 2q Ref.: Ye, et al 2010 Fall, MRS

Fig. 4: Shown is the change in Hall mobility and crystalline structure in the films deposited at different oxygen flow rates in a reactive sputtering process using a Zn- or Al-doped Zn target. In the sputtering process, the flow of nitrogen gas remains high. By adjusting a dominant reaction from between Zn and N to between Zn and O, zinc nitride (Zn3N2), zinc oxynitride (ZnON), nitrogen-doped zinc oxide (ZnO:N), and zinc oxide (ZnO) films can be produced. High mobility is attained in the films in which crystalline structures of Zn3N2 and ZnO are suppressed.

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sccm in the test (Fig. 4), crystalline structures film before and after annealing. It is clear that down in a catastrophic way. Typically, the for both Zn3N2 and ZnO crystalline structures mobility increases significantly from 38 to shelf life of ZnON is about several weeks if it have been significantly suppressed and films 135 cm2/V-sec, while the carrier concentration is exposed to air without any passivation or deposited are either amorphous or highly is reduced, most likely due to defect reduction protection. Annealing, however, can signifi- disordered nanocrystalline ZnON films. The in the film through annealing. cantly extend the shelf life of ZnON film from amorphous fraction and composition of ZnON Another interesting difference between several weeks to several years. ZnON TFTs films vary depending on reactions involved in IGZO and ZnON is illustrated in Fig. 3(e). are often less sensitive to ambient conditions the film-deposition process. Several ZnON films tested have shown an tested against other TFTs of the same struc- As the oxygen flow rate is increased to increase in Hall mobility as carrier concentra- ture. However, the threshold voltage, Vth, of about 50 sccm, the reaction rate of zinc with tion decreases in the region to below 1020 cm-3, ZnON TFTs is often more negative compared oxygen becomes higher than that of zinc with which is different than the trend reported for to other metal-oxide TFTs. As experienced nitrogen, and ZnO crystalline structures IGZO. This indicates that in the ZnON films, with any other new semiconductor, the inte- emerge. However, nitrogen is still embedded ionized impurity scattering remains dominant grated process to fabricate ZnON TFTs will be in the film, as indicated by the shift of ZnO- even in a region where it is relatively weak, different from that for IGZO, and some crystalline peaks in XRD and GXRD measure- which, in turn, indicates that the potential changes will have to be implemented. Some ment. Since the film has a clear zinc-oxide barrier on the conduction-band minimum in of these features are challenges that need to be crystal-line structure, it is often called nitro- the ZnON films is relatively low. addressed, but some of the unique film prop- gen-doped zinc oxide (ZnO:N). The reaction Actually, ZnON should be closer to the erties can be utilized to improve the TFT between zinc and oxygen becomes dominant ideal model shown in Fig. 3(b) if the disorder- stability and reduce the costs for manufactur- as oxygen flow further increases or nitrogen ing from the multi-anions is not too severe. ing TFT backplanes. So far, ZnON active- gas decreases, and the film becomes a ZnO Since only Zn serves as the cation in the matrix TFT backplanes for a 3.8-in. QVGA film even though a lot of nitrogen is still pres- ZnON films, the interactions between neigh- display have been tested with yields close to ent in the process. It is evident that the reac- boring cations are more uniform, and the 100%. A field-effect mobility of about tion rate between zinc and oxygen is much distribution of metal cations is less complex, 100 cm2/V-sec has also been achieved by higher than the reaction rate between zinc and despite their amorphous arrangement. This groups with ZnON TFTs. nitrogen in the reactive sputtering process. increases the probability of maintaining an In summary, IGZO TFTs have successfully This also explains why an abnormally high interaction distance larger than the distance demonstrated higher mobility than a-Si TFTs ratio of nitrogen over oxygen is often needed between the cation sites. Therefore, the and lower cost than LTPS TFTs. Even though to produce a ZnON film, why the transition degree of interruptions on the conduction- efforts to fully implement IGZO TFTs in dis- regime from Zn3N2 to ZnON is very small, band minimum, or potential barriers, in the play manufacturing are still ongoing, searches and why a Zn3N2 crystalline structure can be single-metal oxynitride should be reduced for even better semiconductor materials have suppressed even by a small amount of residual compared to that of IGZO film. As a result, a clearly already started. In order to make TFTs oxygen. higher mobility than IGZO can be achieved. with a performance as high as that for LTPS Although the films made from the process ZnON has some unique characteristics TFTs and as low cost as that for a-Si TFTs, can be Zn3N2, ZnON, ZnO:N, or ZnO, Hall- compared to other metal oxides. For example, breakthroughs are needed. ZnON TFTs have effect measurements show all of the films the wet-etch rate of ZnON is at least 10 times been demonstrated here as one candidate to produced are n-type semiconductors. There- faster than that of IGZO. However, ZnON is achieve this goal, but more progress is expected fore, the mobility of the films should rely on more resistant to dry plasma. Under typical in the future. n the conduction band of the materials. The plasma dielectric etching or metal-etch result in Fig. 4 shows a clear trend that the process conditions, the etch rate of ZnON is higher mobility is achieved in the films in about 10 times slower than that of IGZO. which the Zn3N2 and ZnO crystalline structure It is also observed that the surface of ZnON is suppressed. The variation of mobility in a is more hydrophilic than other oxides. It can ZnON film depends on its composition, amor- absorb moisture and pollutants in the air and Submit Your News Releases phous fraction, and possible defects in the form weak acids or bases that accelerate Please send all press releases and new film. Table 1 shows the mobility of a ZnON oxidation of the film from the top surface product announcements to: Jenny Donelan Table 1: Hall mobility and carrier concentration of a ZnON film are shown before and after annealing. Information Display Magazine 411 Lafayette Street, Suite 201 Resistivity Hall Mobility Carrier New York, NY 10003 2 -1 -1 -3 Film Ohm-cm cm V S Concentration cm Fax: 212.460.5460 ZnON as deposited (50°C process) 2.7E-02 38.5 -9.06E+18 e-mail: [email protected] After anneal at 400°C for 1 hour 1.6E-02 135 -2.82E+18

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display marketplace

AMOLED Production: Entering a New Era?

Active-matrix organic light-emitting-diode (AMOLED) displays have many attractive features that have led companies to attempt to manufacture them, but one country – Korea – currently accounts for the vast majority of AMOLED-display manufacturing capacity. Ambitious investment plans in China, Japan, and Taiwan could change this balance over the next several years.

by Paul Semenza

MONG the many compelling features China, as well as a resurgence from companies Korea: Samsung Display and LG Display Aof active-matrix organic lighting-emitting- such as Japan Display, Inc. (JDI), Panasonic, Samsung Display, the result of the merger of diode (AMOLED) displays are image quality AU Optronics Corp. (AUO), and Innolux, all Samsung Mobile Display and Samsung (wide color gamut, viewing angle, and high of which have implemented restructuring and Electronics’s LCD business, is the dominant contrast), thinness, and weight (no backlight consolidation of existing AMOLED-display producer of AMOLED displays, starting mass and the potential to be made on a single sub- fabs. The key to building out new capacity production in 2007 and accounting for more strate, which could be plastic or metal), and will be to master manufacturing technologies than 95% of shipments in 2012. The com- manufacturing process (simple stack, small that enable scaling to large substrate sizes. pany’s capacity thus far has been built around amounts of materials, and few optical films). During the decade since the first AMOLED displays were produced, dozens of companies have made at least some efforts toward mass production. Despite the promise of the technol- ogy, the reality has been that developing the equipment, materials, and manufacturing processes to make OLED displays at high yield rates has been very difficult. Even the dominant firms, Samsung Display and LG Display, have struggled to scale the technol- ogy to make TV panels. At the same time, TFT-LCD technology has continued to improve, most recently in the form of 4K × 2K panels. Through 2012, the vast majority of AMOLED- display manufacturing capacity has been in Korea, primarily with Samsung Display but increasingly with LG Display as well through investments in Gen 8 fabs for TV panels (Fig. 1). There is a great deal of uncertainty with regard to future production plans, but it is likely that there will be several new fabs in Fig. 1: AMOLED-display manufacturing capacity has been centered in Korea, but new or Paul Semenza is Senior Vice President with expanded production is expected in other countries over the next few years. Note: Taiwan NPD DisplaySearch. He can be reached at capacity includes AUO’s Singapore fab. Source: DisplaySearch Quarterly FPD Supply/Demand [email protected]. & Capital Spending Report.

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Gen 4 and, starting in 2011, Gen 5.5 lines, allow for scaling to larger substrate sizes than are vapor deposited through a fine metal which focus on displays for smartphones and is the case when using a fine metal mask with mask). In July 2012, Panasonic announced a other mobile devices. a point source. Samsung is also believed to be joint development program with Sony based These lines use the low-temperature poly- developing oxide-TFT backplanes and white- on printing technologies. silicon (LTPS) approach for the fabrication of OLED deposition for future Gen 8 production, Other companies in Japan with ongoing the active-matrix backplanes, which are then as it may be easier to scale than LTPS AMOLED-display efforts include Epson, Ortus, cut in half (for the Gen 4) or quarters (for the backplanes. and Sharp; however, none are anticipated to Gen 5.5) for organic-material deposition. Vapor While Samsung will have the largest begin mass production in the near future. deposition of RGB subpixels is achieved AMOLED-display manufacturing capacity primarily via fine-metal-mask patterning. through 2014, it is possible that LG Display Taiwan: Consolidation, Limited Samsung has been using its Gen 5.5 A2 line, could catch up in 2015 if it continues on its Production which consists of five phases, to experiment current Gen 8 investment path. Samsung AUO has two OLED lines for the production with new manufacturing technologies, includ- would likely maintain its market share for of small-to-medium OLED products, based ing laser-induced thermal imaging (LITI) for some time, however, as it continues to on LTPS backplane and evaporation color materials deposition, flexible substrates, and increase smartphone-display production and is patterning, a Gen 3.5 line, and a half Gen 4 thin-film encapsulation. (For more about moving toward the production of panels for line (AFPD in Singapore). In 2012, the com- current large-area OLED-display manufactur- tablet PCs and other larger-screen sizes. The pany started a Gen 6 line using oxide-TFT ing processes, see the article “RGB Color outcome may depend on whether Samsung backplanes and the full deposition of white Patterning for AMOLED TVs” in this issue.) pursues OLED TV as rapidly as LG Display OLEDs; it is believed that Sony’s 56-in. RGB LG Display did not start mass production of or focuses instead on smaller, mobile displays. 4K × 2K AMOLED TV was produced by AMOLED displays for mobile devices until AUO. Innolux owns a former TPO Gen 3.5 2011, as it focused on high-resolution and Japan: Fewer, Larger Players fab that uses LTPS backplanes with white wide-viewing-angle LCDs for mobile devices. Japan Display, Inc., (JDI) was formed via the OLEDs and a Chimei EL Gen 3.5 fab that The company also started out with Gen 4 merger of the mobile-display businesses of previously produced bottom-emission production, but within one year, pilot Gen 8 Hitachi, , and Sony, and produces AMOLEDs. Wintek has also been developing production began, focusing on AMOLED-TV AMOLED displays using Gen 2 (formerly AMOLED-display production. panels. The company began shipping 55-in. Hitachi) and Gen 4 (formerly Toshiba) fabs; TV panels at the end of 2012, but is not expected Sony did not transfer its AMOLED-display China: Many Announcements, Little to manufacture in large volumes until 2014, assets to the new company. JDI is planning to Capacity Thus Far when it starts deposition on full Gen 8 sub- add new capacity to the Gen 4 line (organic There are many panel makers in China that strates (it is currently using half Gen 8 sheets deposition on half-substrates), with the capa- have built R&D lines for AMOLED produc- for organic-material deposition) in its M2 fab. bility to process WOLED or RGB. JDI has tion, including BOE, CCO, Shenzhen China LG Display has adopted two new approaches also acquired Panasonic’s Gen 6 a-Si LCD Star Optoelctronics, IRICO, Tianma, UDT, in its Gen 8 fab – oxide-TFT backplanes and line and will install equipment to convert the and Visionox. Most of these fabs are Gen 2, white OLEDs with a color filter. Both of fab to LTPS production in 2013, with organic- with the exception of Shenzhen China Star these approaches are believed to enable scal- material deposition on the substrate cut into Optoelectronic Technology’s (half Gen 4) fab, ing to larger substrate sizes – the oxide-TFT sixths. and all use LTPS backplanes and RGB pat- approach because it can use modified a-Si Sony, historically a leader in AMOLED- terning. BOE, China Star, Hehui Opto, TFT processes and the white-OLED approach display production, previously produced IRICO, Lai Bao, and Truly have announced because it does not require the deposition of AMOLED displays for its Clie PDAs, as well their intention to go into production with Gen individual red, green, and blue organic emit- as the first AMOLED TVs. Sony has main- 4 fabs over the next few years; BOE, China ters on the subpixels. In order to fabricate tained its facilities and integrated into Sony Star, Tianma, and Visionox are planning Gen RGB subpixels, color-filter material is then Semiconductor and is currently producing 5.5 fabs, and Foxconn has announced its patterned on top of the white-OLED emitting very-high-end AMOLED monitors for master intention to build a Gen 6 line. Finally, BOE area. The process to add color filters is much video and medical applications. is planning a Gen 8 AMOLED-display fab for easier than the process to deposit RGB Panasonic has been developing AMOLED- making TV panels in Beijing, using oxide organic materials. display production for years at its R&D center. TFTs and white OLEDs. Samsung Display has also announced that it In 2012, it installed ink-jet tools at a line in For a number of these companies, the will begin Gen 8 production, although the Himeji for AMOLED-TV pilot production. schedule and probability of success are uncer- exact timing is not clear. This new fab will The company has been pursuing AMOLED- tain. Many are driven by provincial initiatives cut the LTPS backplane into six sheets for display production with oxide backplanes, to develop high-technology manufacturing, organic-material deposition. Samsung has ink-jet printing, and Sumitomo Chemical’s but the supply chain and human-resource pool been developing a proprietary evaporation (much of the original patent portfolio was are limited in some cases. However, a steady technique called small-mask scanning, in acquired from Cambridge Display) soluble stream of new ventures is targeting AMOLED- which a linear vapor-deposition source is polymer AMOLED materials (as opposed to display production. Among the newest players scanned along the mask, which is believed to more common small-molecule materials that are IMEC, which announced that it intends to

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display marketplace

build a Gen 3.5 AMOLED fab in Nanjing, that was able to drive the OLED devices, rating organic material from a point source with help from JGroup. Blue Excited Tech- which are diodes, with sufficient levels of through a fine metal mask to define the sub- nology (BEX) plans to produce small AMOLED current density. LTPS fabs were limited to pixels. The use of this technique at Gen 4 and displays based on blue-coating technology Gen 4 because of the need for an annealing larger sizes has been difficult, due to issues developed at Xinyang Normal University; step that typically uses excimer lasers. Due to such as sagging of the mask, shadowing and the company plans to build a Gen 4 fab using limitations in laser power, the Gen 4 substrate angular-distortion induced by the large angles, oxide-TFT blue OLED material and color was the largest area that could be annealed by and the necessity of cleaning the masks. conversion for color patterning. the laser in a reasonable amount of processing Samsung has recently been working on scan- time. However, developments over the past ning a linear source across a mask, which Scaling Up to Larger Substrate Sizes recent years have reduced some of these could address some of these challenges; Most existing AMOLED-display fabs are barriers. First, more powerful excimer lasers, another approach is vertical scanning, in Gen 4 or smaller. This is due to limitations as well as multiple scanning, have enabled which both the mask and substrate are in scaling both the TFT backplane array and Gen 6 and potentially larger LTPS backplanes. oriented vertically. organic materials deposition to larger sub- Second, oxide-TFT technology, which is simi- To scale up to very large substrate sizes, strate sizes. As with TFT-LCDs, there is an lar to standard a-Si TFTs but provides higher however, it is likely that new approaches are imperative in the AMOLED-display industry levels of current density, has been brought needed (Fig. 2). Two that have been in devel- to move to larger fab sizes in order to increase into mass manufacturing, enabling Gen 8 opment for some time are LITI and ink-jet revenues and reap economies of scale; so AMOLED backplanes to be produced. printing. In LITI, the organic material is much of the industry focus is in these two It is common in AMOLED-display manu- embedded in a sacrificial film that is put on areas of manufacturing technology. facturing to cut the TFT-array substrate down top of the substrate and then exposed to a In the past, AMOLED backplanes have to a smaller size for the back-end process of laser, which causes a transfer of the organic been limited to Gen 4 substrates. This was organic-material deposition. This is due to materials to the substrate. In ink-jet printing, because LTPS was the only TFT technology limitations in the standard process for evapo- the organic materials are suspended in solu-

Fig. 2: While the use of a fine metal mask is the most prevalent method for deposition of the organic material layers in AMOLED displays, newer larger fabs are pursuing other approaches that might be more easily scaled to large sizes. Source: DisplaySearch.

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tion, which is then forced through ink-jet print to be made in thin, flexible formats with little and the requirement for some sort of thin-film heads onto the substrate. While these tech- diminution of display performance. encapsulation to protect the organic materials. niques show great promise, neither has been Both Samsung Display and LG Display are Neither of these challenges has been sur- put into mass production. (The January/Feb- working on the production of AMOLED mounted in mass production, and it is likely ruary Industry News section of ID magazine displays on flexible substrates and face a that we will see a series of steps, first using discusses new ink technology developed by different set of manufacturing challenges; flexible substrates to make fixed, possibly Merck and Epson for the manufacture of large notably, manufacturing yield and performance curved, displays, and then moving to full OLED displays.) of the TFT backplane on flexible substrates flexibility in future product generations. n The newest approach to be tried is the white-OLED approach combined with the use of color filters, which LG Display is using (as described earlier); in this approach, a single layer of white-emitting material is deposited on the substrate and a color-filter layer is used to define the RGB (sometimes RGBW) sub- pixels. This approach eliminates the need for separate deposition steps for each of the primary colors, a source of many of the challenges with fine-metal-mask deposition. A downside is the added complexity of a color-filter layer and the potential for lower efficiency due to absorption losses.

Next Steps Several upcoming fabs are planning to adopt both oxide-TFT backplanes and white OLEDs, as these technologies appear to be most easily scaled to larger substrate sizes. It should be noted that both of these techniques are new to mass production, and it is likely that there are unforeseen barriers to mass production that could impact schedules and output. Finally, it cannot be forgotten that AMOLED displays currently face competition from TFT-LCDs in virtually every screen size and application. Thus, it is imperative that AMOLED-display manufacturing costs, currently a multiple of equivalent LCDs in large sizes, come down dramatically. In some cases, notably in China, AMOLED displays are viewed as an entry into the FPD industry that has greater potential than LCD manufac- turing, which has become mature and extremely competitive. A different approach to the production of AMOLED displays could be in flexible displays. It is extremely difficult for LCDs to be made in fully flexible, or even curved, formats, due to challenges with cell-gap maintenance and backlighting optics. Tech- nologies such as electrophoretic technology are very amenable to flexible formats, but do not have the visual performance required for video and other key applications. AMOLED- display technology is one of the few display technologies that has demonstrated the ability

See Us at Display Week 2013, Booth #939 ID Heikenfeld p30-34_Layout 1 3/22/2013 8:49 PM Page 30

enabling technology

Flexing and Stretching

So you work in displays? You may soon be working in flexible electronics too. Author Jason Heikenfeld, associate professor with the School of Electronic and Computing Systems at the University of Cincinnati, looks at several of the most interesting developments in flexible electronics.

by Jason C. Heikenfeld

HEN I began my academic career in often highly qualified to work in flexible/ ing to Janos Veres, Program Manager for 2005,W I thought my display days were over. The rollable electronics as well. Printed Electronics at PARC, “Flexible and dominance of LCDs was clear; what research In this article, I hope to show that others in printed electronics is a field rich in opportuni- was there left to do? Was I ever wrong, as the display community a few things they may ties for PARC to deliver high-value innova- displays have remained a rich area of work for have not seen before by touching on some of tion by combining its expertise in material me and countless other people, and there con- the interesting things happening in flexible/ science, device and circuit design, process tinues to be numerous needs for novel display stretchable electronics. This is not a compre- technology, and prototyping. Our clients technologies. Since I became involved with hensive review by any stretch (or flex); rather, range from chemical companies to makers of displays more than a decade ago, I have worked I hope to convince readers that flex is a grow- consumer products.” A great deal of PARC’s with and published on just about every display ing and exciting area with applications that pioneering work in printed displays is now type: plasma/liquid/solid, emissive/transmissive/ might complement more traditional work in being deployed in exploring the limits of reflective/transparent, flexible/rollable, 3-D, etc. displays by citing some examples of this work printed circuits and their use, for example, in More and more, I find myself working in being done in the industry. smart sensor systems. PARC has recently flexible electronics too, and the segue into PARC: A logical place to begin this sampling demonstrated printed, disposable, blast flex has been quite natural. Why? Well, like is the Palo Alto Research Center (PARC), a dosimeters that monitor traumatic brain injury many of us “display folk,” I have always been prime source of display and print experts flex- in soldiers on the battlefield. The tape-like intimately familiar with low-cost and large- ing their muscles (or devices) in the flexible- blast dosimeter records the severity and the area microfabrication, hybrid integration of electronics area. PARC was an early pioneer number of blast events during 1 week in order organic and inorganic materials, low-tempera- in the late 1990s in flexible-display technol- to enable early administration of medical care. ture processing, and print-based patterning. ogy, due, in part, due to efforts in ’s The fully functional sensors are fabricated by Furthermore, to make something rollable, the bichromal ball technology for methods such as lamination, die cutting, solu- foremost enabler is often to make the entire (a rotating charged ball with black on one side tion processing, and printing – all compatible device as thin as possible, typically <100 µm and white on the other), and also, in part, to its with inexpensive roll-to-roll processing. thick. Display engineers are constantly look- deep expertise in print-based patterning. If American Semiconductor and MC10: ing for ways to thin down the materials in a you look at PARC’s activities today (Fig. 1), Let’s say that you are a display integrated display to bring about better aesthetic appeal, you will see a broad spectrum of flexible circuit or row/column driver expert, and you impact resistance, and the thinness and lightness electronic technologies ranging from flexible are excited about chip-on-glass, but think that required for devices such as smartphones. The batteries with a bend radius of <3 mm and a flex has nothing to do with you or with a point is that if you work in displays, you are capacity >5 mA-hr/cm2, jet-patterned active- traditional CMOS foundry. Think again! matrix backplanes (680-µm pixels), and a Today, the very high temperatures and ultra- Jason C. Heikenfeld is an Associate Professor flexible 75-dpi PIN image sensor array, just to high-resolution capabilities found in Si in the School of Electronic and Computing name a few. PARC develops these technolo- foundries can be realized in rollable form. Systems of the University of Cincinnati; gies through a variety of projects ranging Compared to conventional flexible thin-film- telephone 513/556-4763, e-mail: heikenjc@ from basic materials science all the way to full transistors (TFTs), you can obtain a few 100× ucmail.uc.edu. systems prototyping/demonstration. Accord- improvements: an increase in the best mobili-

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Flex Electronic Building Blocks at PARC Example Flexible Systems/Components at PARC

Amplifier Active matrix TFT

Temperature sensor Flex battery Flexible Memory Compliant High-Density Interconnect

Ring oscillator Shift register

Decoder RF Inductor Coils Flexible Image Sensor Complementary logic

Fig. 1: PARC’s wide spectrum of foundational flexible electronic components and systems include a growing library of additively printed devices and circuits, novel approaches for compliant packaging of components, and flexible sensor arrays. Source: PARC.

ties for amorphous transistors on plastic from flexible hybrid systems development as well magnitude faster and smaller than printed ~1 cm2/V-sec to ~100s of cm2/V-sec for as design engineering, including design, veri- TFTs for features that have always been crystalline Si and a reduction in the feature fication, layout, and testing. It now also pro- required but never before available in flexible sizes from approximately 5 to15 µm for vides FleX Silicon-on-Polymer technology for electronics.” So, as a side note, if you want to display lithography down to approximately flexible CMOS. Initial production runs of its realize a completely rollable display with no 50–150 nm. The key enabler for flexing is the FleX technology have begun, and regarding rigid parts, you now have every component same: make the CMOS film as thin as possible. future volume product, Richard Chaney, available to you in order to make this a reality. As shown in Fig. 2, American Semiconductor General Manager at American Semiconductor, Now, can you take flexible Si electronics uses a wafer-thinning process on silicon-on- notes, “FleX is a repeatable, manufacturable one step further, making them conformal, insulator (SOI) substrates to make flexible ICs process demonstrated in prototype volumes stretchable, and biocompatible? The University with from 10 to 10,000s of chips per wafer. and is currently supported using a Jazz of Illinois and startup MC10 have answered However, to reduce fragility, the company Semiconductor CMOS foundry silicon. We that affirmatively, demonstrating several applies a polyimide film before the thinning convert advanced ICs from commercial exciting new conformal electronics in recent process is performed to remove the thick Si foundries into flexible chips by using our years (Fig. 3). They have shown sophisticated support wafer. CMOS wafers thinned to proprietary low-cost FleX process and inte- “epidermal electronics” that is applied to the <20 µm have been demonstrated to achieve grating them with printed electronics to form skin in a manner similar to that of a temporary a bend radius of 5 mm with no change in flexible hybrid systems. This new technology tattoo or expandable electronics on a balloon the electrical characteristics after flexing. is ultra-thin, rugged, bendable, and low cost. catheter for sensing or for localized delivery American Semiconductor is a flexible elec- Our FleX technology provides logic, memory, of therapy. The key to moving beyond flex to tronics and services provider that performs and wireless capability that is orders of stretch/conformal is the ribbon-like sections

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enabling technology

Flex ICs Tested, Concave and Convex Flexible & Semi-transparent CMOS Foils

FleX Silicon-on-Polymer Roadmap

TRL4

TRL6

TRL7

Today

Fig. 2: Above (left) are examples of flexible ICs based on American Semiconductor’s Flexible Si CMOS (FleX) technology. At upper right are flexible, transparent CMOS foils; at lower right, the company’s roadmap for developing and delivering the technology. Source: American Semiconductor.

between functional “islands” of Si. These released super-thin glass that challenges the meters in radius and allows roll-to-roll interconnecting ribbons have a concertina-like notion that flex means low-temperature processing (see examples performed by ITRI geometry and can be stretched by more than processing and the need for sophisticated in Fig. 4). However, at the present time, it is 50%, which is also just about how much human moisture/gas barrier layers. Flex electronics not yet thin enough for personal foldable or skin can stretch. One of MC10’s mottos has that require dimensional and thermal stability, rollable applications, a capability that been “electronics anywhere,” and, more hermeticity, transparency, and a high surface currently only plastic substrates can provide. recently, the company has been focusing on quality on which to build may work better When it comes to substrates for flexible appli- reshaping electronics to conform to the human with flexible glass than with plastic substrates. cations, your options are as follows: you can body for digital health applications. Accord- Even polyimide substrates are not compatible now process on conventional transparent ing to Amar Kendale, MC10’s VP of Strategy with conventional poly-Si temperatures, and PEN/PET flex substrates at <150°C, you can & Market Development, “Epidermal electron- stainless steel has its own host of issues (such use yellow-colored polyimide which allows a ics enable constant medical monitoring every- as the need for planarization). Glass, on the bit higher temperature processing up to where. MC10’s ultra-thin skin-mounted sensors other hand, can be made with the fusion draw ~350°C and is the workhorse of all flexible can manage conditions continuously so that process invented at Corning, such that the outer electronic interconnects in the electronics they do not worsen or reach a crisis.” This glass surface is never touched during forming, industry, and now you have access to transpar- constant monitoring is made possible by using providing a pristine surface. Dr. Sean Garner ent glass that allows all the processing tem- devices that are so thin that activities such as of Corning notes that “Corning Willow Glass peratures and materials that can be found in a football, firefighting, or sleeping can be per- is an enabling component for both display and conventional modern LCD manufacturing formed without any interference from the non-display applications that allows for thinner, facility. Furthermore, as mentioned previ- device, with medical data provided wirelessly lighter weight, or conformal device designs.” ously, the world of crystalline Si is now via Bluetooth or other communication means. Willow Glass allows processing up to flexible, so there are many options. Corning: Glass substrates are a familiar 500°C and is available in samples down to a Flex Tech: In flexible electronics, there is area to most of us in the display industry. thickness of 100 µm. This certainly satisfies room for everyone (Fig. 5). Organizations Corning, Asahi, and several others have now flexibility and bending down to several centi- such as the FlexTech Alliance (formerly the

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“Epidermal” Electronics Stretchable Electronics

in the bottle outside the bottle

LED antenna

ECG/EMG temperature strain wireless sensor sensor gauge power coil

Fig. 3: State-of-the-art medical applications for flex Si incorporate specially designed “ribbons” in between functional Si “islands” to allow fully conformal, even stretchable, electronics.

U.S. Display Consortium) and the market sible to both large and small manufacturers. So How Close Are We? research firm IDTechEx in Europe broadly cover There is no doubt in the market either. Consider Compelling, exciting, and transformative are flexible electronics, and, not surprisingly, many these highly compelling market forecasts by all good descriptors of some the technology of their reports include developments in dis- IDTechEx: “The market for printed and thin- demonstrations now being seen in flexible plays. FlexTech’s view of major flexible- film electronics will be $9.46 billion in 2012; electronics. So what is holding us back? Well, electronics opportunities is two-fold: (1) flexible 42.5% of that will be predominately organic as we know for applications such as displays, and printed electronics enable human-scale electronics such as OLED display modules. Of in some cases it is a technological hurdle products – conformable, portable, or wearable the total market in 2012, 30% will be printed. (stable TFTs and no moisture penetration for – for healthcare, energy, and displays/e-books Initially, photovoltaics, OLED displays, and flexible OLEDs) and sometimes it is market and (2) new, distributed manufacturing with e-paper displays grew rapidly, followed by TFT pull. (Polymer Vision’s beautiful rollable dis- printed electronics is possible for customized, circuits, sensors, and batteries. By 2022, the plays relied on ’s monochrome reflective diversified products. These will be manufac- market will be worth $63.28 billion, with 45% technology, which in those days lacked the tured closer to the end user and will be acces- printed and 33% of that on flexible substrates.”1 response time suitable for video rates. This

Willow Glass with Edge Tab Roll to Roll Ag Ink Printing 500

400 0.1 mm thickness 0.2 mm thickness 300

200 Roll to Roll Polymer Film Roll to Roll Laser ITO Lamination Patterning Bend Stress (MPa) 100

0 0510 15 20 25 30

Bend Radius (cm)

Fig. 4: Above are examples of roll-to-roll processes implemented by ITRI (Taiwan) on Corning’s flexible Willow Glass, and, at right, a plot of bend stress vs. bend radius.

Information Display 2/13 33 ID Heikenfeld p30-34_Layout 1 3/23/2013 9:54 PM Page 34

enabling technology

MATERIALS

Non-Crystaline Materials Nanomaterials Flexible substrates

PROCESSES R2R Manufacturing Printing and Patterning Polymer/Organic Synthesis

DEVICES/INTEGRATION

Membranes Sensors/Detectors Thin-film transistors

PRODUCTS Smart Bandages & Clothing Neuro Prosthetic Devices Sensor Networks Solar Cells MARKETS Military/First Responders Medical Agriculture/Civil Infrastructure Energy

Fig. 5: A view of flexible/printed electronics materials, products, and markets as shown by the FlexTech Alliance. shortcoming may have allowed touch-screen that they will pay extra for, since at the time of smartphones and tablets with full-color LCDs market entry, the competition is rigid electron- to absorb consumer demand for the potential ics, which have beaten the difference between rollable product.) Since the polarizers used manufacturing cost and price down to a razor- for LCDs cause the panels to be too thick for thin margin. Only in the longer term will low- use in a rollable display. The future may be cost arguments such as roll-to-roll manu- limited to rollable OLED displays or e-Paper; facturing potentially allow for more flex however, smartphones do not need to wait for products to win market share based on cost rollable displays to switch over to simple flex alone. for thinness and impact resistance. So, again, do you work in displays? How Other technologies such as flexible elec- long will it be before you work in flexible tronics for medical applications have great electronics too? It may be sooner than you momentum toward commercialization, but realize. It is quite clear that whether your gaining acceptance and approval in medical interest is in displays or in other areas of devices involves a long pathway with numerous flexible electronics, exciting enabling tech- regulatory and other hurdles that must be cleared. nologies are now available, and flexible elec- Roll-to-roll manufacturing has been fully proven tronics and displays will become ever more as well, including ITRI’s demonstration several pervasive in our work and daily lives. years ago of all the electronics needed to enable a smart-card device. The fundamentals and Reference infrastructure for flexible electronics are quite 1http://www.idtechex.com/research/reports/ sound, and continued work is needed in finding printed-organic-and-flexible-electronics-fore- the right applications. You often have to pro- casts-players-and-opportunities-2012-2022- vide something highly desirable to consumers 000301.asp n

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Sustaining or corporate members of SID are companies and  Online access to the Digest of Technical Papers, Journal of SID, universities who are deeply involved in the display industry, typically Information Display Magazine, and proceedings of many affiliated conferences and their archives providing papers for the Digest or JSID and speakers for events, as  Hard copy mailing of Information Display Magazine well as providing minor financial support to SID. In return they  Optional hard copy mailing of Journal of SID, add $50/year receive discounts, free memberships, and valuable marketing  Optional multiple year discount: $190 for two year membership benefits that enhance their brand and business opportunities. (5% discount) or $270 for three year membership (10% discount)  Discounts on SID-Wiley book series on display technology  Discounts on SID-affiliated conferences such as Asia Display, International Display Workshops, the International Display Research Conference, and other information display meetings GOLD SUSTAINING MEMBER-$7,500 annual membership fee  Networking infrastructure including chapter technical meetings, access to SID’s online job mart, online member search, and more!

 10% discount on 5 ~10’ x 10’ exhibit booths at SID’s Display Name Week Symposium & Exhibition  10 free individual memberships with benefits as noted on the right Sustaining Basic $1000 Silver $3000 Gold $7500  One Year $100 Two Years $190 Company name in event bulletins and in each issue of Information Individual Display magazine Three Years $270  Company logo on sid.org for brand support & search engine One Year $5 (Full time student ID Student optimization (SEO) required)  Company video, whether company intro or product specific, Add $50 per year for JSID by mail (no embedded on sid.org’s corporate membership page JSID by Mail? multi-year discounts available)  Four half-page ads in Information Display magazine during the membership period Amount  Signature 14 points toward ranking in the next year’s booth selection

Visa MasterCard Am Ex Card Type (UnionPay with any of these logos is OK) Card Number SILVER SUSTAINING MEMBER-$3,000 annual membership fee Expiration Date Name on Card  10% discount on up to 3 ~10’ x 10’ exhibit booths at SID’s Display Phone Week Symposium & Exhibition  5 free individual memberships with benefits as noted on the right  Company name in event bulletins and in each issue of Information Mailing Address Display magazine  Company logo & link on sid.org for brand support & search engine optimization (SEO) Email  One half-page ad in Information Display magazine during the Click to opt out of event & ID Mag Email opt-out membership period notifications, etc.  7 points toward ranking in the next year’s booth selection Please fill in the details above and fax form to +1 (408) 879-3833 or email it to [email protected]. Please use the space below to list your card billing address if it differs from the mailing address, as well as the names & emails of any members as part of a Sustaining membership. Add a second sheet of paper if necessary. SUSTAINING MEMBER-$1,000 annual membership fee

 10% discount on one ~10’ x 10’ exhibit booth at SID’s Display Week Symposium & Exhibition  3 free individual memberships with benefits as noted on the right  Company name in event bulletins and in each issue of Information Display magazine

 Company name & link on sid.org for brand support & search engine optimization (SEO)  1 point toward ranking in the next year’s booth selection

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Alpha and Omega: Most Exciting Display Technologies at CES

Giant TVs, ultra-high definition, IGZO, and more were among the display showstoppers at this year’s Consumer Electronics Show in Las Vegas.

by Steve Sechrist

NE of the best things about being part that China-based company the one with the tier-one brands are facing from Chinese com- Oof SID is the opportunity to see the “alpha and most 4K sets. The Hisense units ranged from panies, see the specifications for Hisense’s omega” of the display industry. This includes 50 in. to an eye-popping 110 in. on the diago- flagship XT900 4K models, which it calls products or technologies that start in the lab nal with a pixel resolution of 3840 × 2160 U-LED TVs. or are just the germ of an idea to product (see below). The products looked very close Hisense XT900 U-LED 4K TV Specifications concepts and then to shipping displays. Pixel- to commercial status – they were not just • UHD (3840 × 2160) native resolution, dense UHD TVs, anti-reflective materials, and prototypes. To get a look at the competition 120 Hz almost any display technology that is breaking news today was first dreamed of, then dis- cussed, then prodded and poked at during SID’s Display Week; sometimes years before making it to the CES show floor in January. Let’s take a look at the “omega” side of displays and some key trends uncovered at this year’s CES.

UHD Thunder: China Struts Its Stuff The unmistakable display technology of note at CES was ultra-high definition (UHD). Just as 3-D was all the rage 2 years ago, most vendors this year had UHD offerings, includ- ing all tier-one companies, the Taiwanese LCD makers, and almost every Chinese mainland brand. Remarkably, it was the 84-in. UHD TV that seemed to be near-mandatory in Las Vegas, with almost every brand showing mul- tiple TVs boasting a large-screen 4K x 2K set. Among the China-based notables showing 84-in. UHD sets were TCL (also with a 110-in. model) Skyworth (see Fig. 1), Westinghouse, Haier, and Hisense with five models, making

Steve Sechrist is a display-industry analyst and contributing editor to Information Display magazine. He can be reached at Fig. 1: This 4K China Skyworth UHD TV is sourced from CMI Display Taiwan. Photo [email protected] or by cell at 503/704-2578. courtesy Steve Sechrist.

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• WiFi enabled This panel also sports a 10-point discrete picture,” according to Peter Erdman, Hisense • Smart TV with Google TV touch screen, as IGZO allows for more Group VP. • 65-, 84-, and 110-in. screen sizes discrete sensors. According to Sharp, IGZO In terms of the images used at the show, the • 3-D can cycle the power-down state of the panel company did a very good job of simulating • Smart-TV functionality at a very high rate, enabling a far “quieter” depth with its autostereoscopic prototype. It’s • Precise local dimming electromagnetic environment. This allows important to note it was not displaying com- • “Mega” dynamic contrast ratio (the back- the use of much higher sensitivity devices that mercial 3-D film content, but rather multi 3-D light can be completely turned off cannot work with conventional AMLCD layering content that demonstrated the tech- in local regions to greatly extend the panels (see the IGZO write-up below.) nology in a subtler way. On-axis viewing was dynamic range) This Sharp monitor was announced in discernably better than viewing from the sides. • Multi-screen play November 2012 prior to CES. It has a pixel Hisense did say it was using a face-tracking • Detachable camera (Skype calling, density of 137 ppi and will retail at around technology to adjust the 3-D sweet spot, and gesture, and facial recognition) $5000. ViewSonic showed its 32-in. 4K this may have been “overloaded” with the • Voice-control remote that allows voice monitor at CES and said the product will large crowds viewing the screen at the show. activation for on-off and channel changing. launch “sometime in 2013” with pricing to Hisense also showed a transparent 3-D As far as LCD fab sources for the giant be announced. display for digital-signage applications 110-in.-diagonal panels is concerned, I was (Fig. 2). The company used an LCD front- told in the TCL booth by product manager 4K Empowers 3-D plane with passive 3-D capabilities and a Jain Peng “Konan” Jiao that the fab used by In the booth of Hisense, based in Qingdao, mounted backlight with a 1-m (or so) gap in TCL was a result of its Joint Venture Gen 8.5 China, the company was using a 60-in. UHD between where merchandise can be placed. with Samsung, called China Star Optoelec- to show off its autostereoscopic 3-D technol- The objective was to demonstrate how to use tronics Tech (CSOT). Other panel makers ogy. Hisense went so far as to give the prod- the LCD with current 3-D virtual content over with a 4K offering at CES included Sharp uct a model number (GF60XT980), while at any real merchandise in the background. In (using its IGZO technology), Samsung, LG, the same time calling it a “proof-of-concept a storefront configuration, a window with Sony, Panasonic, and Toshiba. model,” with no price or ship date. “By using merchandise behind it can be displayed. a Hisense ultra-high-definition 2160p panel, Hisense sees applications in real-estate 4K Monitors at CES will Probably even at half the normal screen resolution, demos, window advertisements, showcases, Ship First viewers can still enjoy a truly high-definition and around the home. It’s interesting to note that the Panasonic UHD-class 20-in. hybrid tablet/display with a 15:9 aspect ratio could be used as a tablet or desktop monitor. The device includes an IPS 4K × 2K panel and was shown at CES running Windows 8 with an Intel i5 Core (1.8 GHz) and up to 16 GB of memory. With this technology, Panasonic seems to be looking to extend desktop monitors into a new class of device that can also serve double duty as a tablet (albeit in this case, a mighty big one.) The company said it is targeting professionals who need very high resolution (photographers, engineers, and architects.) Perhaps another way to look at the product is as a portable “all-in-one” desktop PC with the advantage that it can be taken into the field. LG, Sharp, and ViewSonic all showed examples of smaller 4K displays with 30-in. panels, and while the LG 30-in. unit was a prototype (found nested in a window wall in the booth), specs include 153 ppi, 500 nits, and 99% of the RGB color gamut. This panel is probably aimed at OEM customers. Meanwhile, Sharp claimed the “world’s thinnest” 4K monitor with its 32-in. diagonal model, which is less than 1.5 in. thick and is Fig. 2: Hisense showed transparent 3-D technology for digital-signage applications at CES. based on its new zinc-oxide-TFT technology. Photo courtesy Steve Sechrist.

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Most UHD TVs shown at CES were 3-D oped with Taiwan-based CMI by using a 3-D technology, including Vizio, which capable. Some of the vendors were using lenticular lens along with stereo image demonstrated passive technology in two sets: UHD to create an autostereo TV image. processing by Dolby, converted to multi-view 65- and 70-in. models in its XVT (UHD TV) These included Dimenco, showing an 11.6-in. and streamed over a Vudu encoding format. Smart-TV series. switchable prototype using the company’s Stream TV showed a set (UHD 60 in. at “Nabla” lenticular lens and new liquid-crystal 2160p) with a non-lenticular 3-D stack com- Content is Still King, But Where Is It? cell design with low-voltage switching. bining diffractive and refractive optics to What was interesting at CES was that 4K Dimension Technologies, Inc. (DTI) also had guide light in the right direction within an glass (UHD TVs) seemed more prevalent than an autostereoscopic technology on hand, with established viewing distance. the content needed for viewers to take advan- an 8-view, glasses-free display using a unique On the standard (glasses-based) 3-D side, tage of the high-pixel-density displays. It is time-multiplex backlight system. Dolby most major players (Sony, LG, Samsung, etc.) the familiar Catch-22 cycle: there is no con- showed a new autostereo panel they devel- continued to show their active and passive tent, so no one buys the displays, so no one makes the content since no one is waiting to view it. One way HDTV overcame this content hurdle was through the DTV transition and through over-the-air broadcasts of HD con- tent. In that vein, LG did show a 2012 joint pilot venture with KBS (Korean Broadcasting System) that used 4K over the air. The antenna technology used for this venture was on display in LG’s booth. This, along with full-HD up-scaling and of course producing (or re-mastering) original film content to air on giant, high-pixel-density screens will eventually fill the 4K content pipe and help drive demand as we move from full-HD into new UHD-display frontiers. It’s hard to imagine the 500 lines of last century’s SDTV lasting for more than 50 years in light of the DTV transition, full-HD broadcasts, and even the (albeit limited) 3-D sports and event broadcasts of today. (For more about the timeline for UHD broadcasts, see NHK’s article, “Super Hi-Vision as Next-Generation Television and Its Video Parameters” in the November/December 2012 issue of ID.)

Biomimicry: Sharp’s Moth-Eye Technology An example of the aforementioned alpha– omega technology progression from SID to CES is the Moth-Eye nanotechnology described at SID 2011 in a presentation show- ing how it enabled a dramatic reduction in glare. At this year’s CES, prominent in the Sharp booth was none other than a Moth-Eye demonstration of how this “biomimicry” anti- glare technology will be used by Sharp to remove glare from indoor screens, with an aim toward tuning it for outdoor purposes in the long term (Fig. 3). Moth Eye creates nanohexagonal patterns of bumps on a film surface (spaced 300 nm Fig. 3: Sharp Moth-Eye display shows technology introduced at SID in 2011. Photo courtesy apart) that are smaller (200 nm) than the Steve Sechrist. wavelength of visible light, creating a contin-

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uous refractive-index gradient (removing the Sony’s new flagship Xperia Z smartphone The CGS backplane is based on crystalline air–lens interface.) Moth Eye gets its name (Fig. 4) attracted lots of attention on press day silicon, with an electron mobility up to 600 from nature, which uses this strategy in com- at CES. The phone features a 5-in. times faster than that of ordinary amorphous mon night-flying moths to prevent light display and a remarkable water-resistant design. silicon and up to 6 times faster than that of reflection and thus help the moths conceal Meanwhile, Sharp announced its continuous- low-temperature polysilicon (LTPS), the themselves from predators. Early reports of grain-silicon (CGS) 5.1-in. smartphone for current technology in the iPhone retina class the technology go back as far as 2003, with the Japanese wireless market that boasts 443 iPhone 4, according to Sharp. The panel is development credited to MacDermid Autotype ppi. Sharp said its CGS LCD panel is also being made at Sharp’s Mei Plant No. 3, (Autoflex film) and Fraunhofer Institute for available for the OEM market. It first showed using technology jointly developed along Solar Energy in Germany. the technology in October at CEATEC, where with Semiconductor Energy Labs (SEL) in Truth be told, commercial Moth Eye was its IGZO technology took the Top Innovation 1998. SEL is the same company that helped first revealed by Sharp at CEATEC in Japan Award in electronic components. Sharp with IGZO. Sharp said its new full-HD last October, when the company announced its Aquos Quattron (3D XL vintage) with sizes ranging from 46 to 80 in., all due to feature the new technology in 2013 product roll-outs.

The Move to Giant TVs At the pre-show press conference, Sharp (and others) indicated the company will continue its large-and-larger display strategy, selling displays that top out at 90-in. on the diagonal. At the press conference, Sharp said it will migrate to the 90-in. sets from the current 80-in. ones based, in part, on U.S. consumer numbers that show the plus 60-in. category is the fastest growing size in the TV space. In 2011, 60-in. sets were just 4% of the LCD-TV market in terms of revenue, according to Sharp. That number has grown to 20% of LCD-TV revenue. The company plans to offer 21 models that are 60 in. and up, at prices as high as $10,000. Look for more big sets from all major LCD players as they tran- sition to UHD sets in the middle of this year.

China’s Full-HD Mobile Displays Even with the Mobile World Congress event taking place just weeks after CES, the China smartphone brands all used CES to launch full-HD handheld displays that are sure to dominate the wireless smartphone and tablet space in 2013. Tier-one brands such as Samsung and LG only hinted at these new higher-pixel-density models. Case in point was Huawei, which announced a 5-in. 1080p display with an impressive 443-ppi pixel density in its new flagship Ascend D2 Dream Phone. The Grand S (flagship model) from ZTE is a 440-ppi 5-in. 1080p display. Other China-based brands to offer a full-HD hand- held included the Vizio Via (5-in. full-HD screen), the Alcatel Scribe X (with a 1080p 5-in. display), and the Lenovo K900 with a 5.5-in. 1080p IPS display that uses an LG Fig. 4: Sony’s Xperia Z, a water-resistant 5-in. full-HD smartphone, stole the show in the AMLCD panel. mobile space. Photo courtesy Steve Sechrist.

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5-in. set also achieves a brightness of 500 Meanwhile, Samsung is using the tried-and- the other. This configuration allows the cm/m2. true RGB color OLED approach that brought device to act as a regular smartphone, but also the company OLED display dominance in the an e-Book reader and platform for applica- OLEDs Almost Eclipsed by UHD small-to-medium display space. To date, tions not requiring the more memory-hungry Sony and Panasonic, along with LG and no one sells more AMOLED panels than color LCD. The company also had flexible Samsung, all had an OLED TV story to tell Samsung. (For more about the two different displays at an evening post-show event; one at CES and most (except for LG) were still approaches, see the article “RGB Color prototype was Central Standard Timing’s singing the old “sun will come out tomorrow” Patterning for AMOLED TVs” in this issue.) “CST-01” bendable watch display that’s worn song with beautiful images and no specific Japan-based Sony and Panasonic were both on the wrist. While multiple E Ink tablets launch date. Meanwhile, LG did take the present at CES with new 56-in. OLED panels, were present at CES, we were told by Marketing plunge, announcing just prior to CES that it therefore claiming the “world’s largest” title VP Sriram Peruvemba to look for the technol- had begun taking pre-orders for its 55-in. from Korean manufacturers. But at this late ogy to begin moving more rapidly in the digital- (55EM9700) TV. A February 2013 delivery state in the OLED-TV game, one may rightly signage space, as bi-stable, low-power, and was scheduled for the new OLED 55-in. ultra- ask whether without a model number or ship ultra-thin displays empower a growing class slim sets in Korea (for about $10,000 a piece). date, does this have any real meaning? of signage that includes retail shelf labels, They are due to ship to the U.S. in the March hybrid static/dynamic posters, and rugged 2013 time frame – finally, some progress. E Ink Displays at CES outdoor displays. LG will be using its white OLED (WOLED) E Ink was a Best of CES display winner with and color-filter approach to get to market with an interesting prototype from a Russian-based IGZO and New Life for LCDs what some call a simpler approach to solving company, Yota Devices. This was a two-sided Finally, this report would not be complete some OLED materials lifetime issues. This Android device, the “Yotaphone,” with a without mention of the ground-breaking approach is based on solutions the company 4.3-in. HD LCD on one side and a IGZO technology shown at CES by Sharp. developed, in part, by using Kodak patents. power-saving E Ink monochrome display on In an extended meeting with Sharp engineers, I learned that the technology transforms displays using its indium gallium zinc oxide with “far superior” electron mobility and much smaller thin-film transistors (TFTs) to boost the pixel aperture ratio (or the amount of light that can go through an R, G, or B subpixel). This development is creating a ripple effect throughout LCD fab design and should enable not just lower power from fewer backlights, but the ability to modulate the panel power (with cycles down to 1 Hz) depending on content – something Sharp calls “variable refresh.” This, plus an off-state panel, will create a virtually electromagnetic (EM) noise- free sensor environment allowing the panel to integrate not just discrete multi-touch sensors, but an entire array of new sensor technology (think bio/cellular, as well as UV sensors, atmospheric, olfactory, you name it ...). In addition to sensor-integration enablement, IGZO allows for deep pixel integration shown in some Sharp models of up to 1000 points per inch. Suffice it to say, the best and brightest were on display at CES, with China beginning to show major strides not only in keeping pace, but in leading the display industry in key technology fields. As 2013 dawns, we are beginning to see the rise of Chinese display technology dominance and perhaps the reassertion of the tried and true LCD (via UHD and IGZO) that are sure to be major factors in the display industry going forward. n

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FIRST LOOK

Society for Information Display SID INTERNATIONAL SYMPOSIUM, SEMINAR, AND EXHIBITION DISPLAY WEEK 2013 May 19–24, 2013 Vancouver Convention Centre, Vancouver, British Columbia, Canada

Announcing Special Topics of Interest on OLED TV v Oxide TFTs v Touch & Interactivity v 3D v Lighting

Visit www.displayweek.org First Look Pages p42-43_Layout 1 3/22/2013 9:51 PM Page 42

The Evolution of Displays through Innovation Papers in this session include: Electronic information displays touch nearly all aspects of modern life. v Progress and Commercialization of AMOLED TV A 55-in. AMOLED TV Using Oxide TFTs and WRGB Design Display Week’s 2013 Keynote addresses will provide a vision of how v v A 65-in. Amorphous-Oxide-TFT AMOLED TV Using Side-by-Side and the evolution of display technology through innovation will change the Fine-Metal-Mask Technology shape and look of the displays of the future. Oxide TFTs Oxide-semiconductor technology is emerging as a strong competitor to thin- KEYNOTE SPEAKERS film silicon technologies for active-matrix backplanes. However, there are several critical issues related to oxide materials and these are associated with the Dr. Kinam Kim, President & CEO, Samsung Display Co. overall characteristics of mass-produced devices, including stability (over time, temperature, and light), uniformity, mobility, etc. Clearly, to be viable these “Displays and Innovation: An Exciting Future” devices need to be made at costs comparable to that of conventional Si-based Our industry is forced to re-invent itself as users are in TFTs. Sessions related to oxide-based TFTs and displays driven by oxide- need of better and more exciting uses for displays. They based TFTs include: want rich, dynamic, immersive experiences, which will v Oxide TFTs I & II require innovations in user interface/interaction as well v Oxide-TFT Reliability as advancements in panel technologies. Challenges along v OLED and Oxide-TFT Manufacturing the path to this exciting future will be presented. v Oxide-TFT Manufacturing Touch and Interactivity Since the launch of touch-enabled mobile devices several years ago, touch has Mr. Bill Buxton, Principal Researcher, Microsoft Research, Microsoft Corp. become an increasingly crucial component for numerous display products. Touch is in an evolutionary phase now, and this year’s papers reflect the diver- “The Social Life of Devices” sity of applications, advanced sensors and materials, and touch integration and Just as we are learning to manage the complexity imposed applications. The topics to be covered include: upon users by individual devices, the problem is shifting v Touch User Experience to that imposed by the ecosystem. Welcome to the shift- v Touch Integration and Controllers ing sands of ubiquitous computing! Managing this v Touch Applications complexity is critical to the continued growth of our v Touch Sensors, Materials, and Manufacturing industry. The means of doing so lies in social computing – amongst the society of appliances. 3D Possibly the biggest commercial story in displays in recent years is the arrival of 3D-ready TVs. Now that they have arrived, the story is far from over. Researchers continue to pursue the different approaches of active-shutter vs. Professor John F. Wager, The Michael and Judith Gaulke Endowed passive glasses technology, and glasses-free viewing is a major challenge that Chair Professor of Electrical Engineering, School of EECS, Oregon State many experts believe must be met in order to make 3D displays truly successful. University This year’s presentations also cover topics such as autostereoscopic 3D displays, “Exciting Developments in Oxide-TFT Technology” 3D and perception, volumetric and holographic displays, and stereoscopic and display applications. The symposium includes the following sessions: Amorphous-oxide semiconductor thin-film transistors Autostereoscopic and Multi-View I & II (TFTs) are transitioning towards commercialization for v LC Technology for 3D I & II active-matrix liquid-crystal-display (AMLCD) applica- v Holographic and Volumetric Displays tions. They also appear well-positioned to meet the more v Light-Field Displays demanding challenges associated with active-matrix v Perception in 3D Displays organic light-emitting devices (AMOLEDs). The objec- v 3D Algorithms and Driving tive of this talk is to review the origins and current status v 3D Applications of amorphous-oxide-semiconductor (AOS) TFTs for v 3D Projection Screens display applications. v Lighting Solid-State lighting has begun to fulfill its promise with regard to saving energy ECHNICAL ROGRAM TO and providing design flexibility. However, LEDs have made more commercial 2013 SID T P inroads in this area than OLEDs, which are currently available only in high-end INCLUDE SPECIAL TECHNOLOGY TRACKS architectural applications. OLED papers therefore form the bulk of this year’s solid-state-lighting sessions, as the industry pushes to develop higher-efficiency, The Society for Information Display’s annual Symposium at Display higher-performing OLED panels. Other solid-state-lighting papers will focus on trends in LED illumination. The symposium includes the following topics: Week offers a wide selection of presentations on display technology OLED Lighting I & II that simply cannot be found anywhere else. This year’s technical v v Human Factors on Lighting program consists of 68 technical sessions with over 250 oral presenta- v Lighting Designs tions and an additional 150 papers to be presented at the Thursday afternoon Poster Session. Join us in Vancouver (Tuesday, May 21 – Friday, May 24) to hear the latest developments in the display industry. MARKET FOCUS CONFERENCES This year’s special areas of focus are OLED TV, Oxide TFTs, Touch and Interactivity, 3D, and Lighting. Here is just a sampling of those After a very successful debut in 2010, the Market Focus Conferences will once topics and other innovations you can expect to find at this year’s again be held in conjunction with Display Week. They will cover the following symposium: two topics: v Touch Gesture Motion (Wednesday, May 22, 2013) OLED TV v High-Performance Displays (Thursday, May 23, 2013) This Special Topic will cover OLEDs specialized for TV applications. Papers on Each Market Focus Conference will concentrate on the critical market develop- advanced OLED TV technologies will be included. OLED-based displays have ment issues facing each of these technologies. Developed in collaboration with several unique attributes that continue to drive interest for television applications. IHS, the conference will feature presentations and panel sessions with execu- Also, the explosion in portable video-capable devices such as tablets and smart- tives throughout the display supply chain. Conference fees include a continental phones place high demands for the displays. 3D television application puts a breakfast, lunch, refreshments, access to the Exhibit Hall and Symposium higher demand on display power, response times, and high dynamic range. Keynote Session on Tuesday morning, and electronic copies of the presentation 42 First Look Pages p42-43_Layout 1 3/22/2013 9:51 PM Page 43

material. Registration for the Market Focus Conferences does not require a three levels. First and foremost, the technical foundations of the topic are treated current SID membership. in detail. Next, recent technical advances are discussed, and, finally, the current Touch Gesture Motion: The 2013 SID Touch Gesture Motion Conference will state of the art and the projection of future trends are analyzed. The Applica- focus on next-generation touch, gesture, and motion-based technologies appli- tions Seminars focus on the application and evaluation of information displays. cable to the display industry. The conference will focus on future technology These seminars benefit both newcomers and experienced professionals. Engineers and interactivity trends – and not so much on what is currently available in the new to assignments in information display find them especially helpful in getting marketplace. Interactive display technologies are one of the most intriguing up to speed quickly. Experienced professionals attend to keep up with recent aspects of the display industry – helping to enable completely new usage models developments in fields closely related to their specialties. Managers attending the in multiple applications. Highlights of the conference will include actual seminars obtain a broad perspective of the display field and a sense of its recent demonstrations from some of the leading-edge innovators, bringing together dynamics. Attendees will receive an excellent set of full-color notes, consisting of many of our senses – sight, touch, motion, sound ... . the instructor’s presentation slides replete with references and illustrations. Ample This event builds on the three prior events presented at past Display Week Con- time is provided for questions from the audience in each session. The speakers are ferences, as well as three separate 2-day TGM conferences. The primary goal is leaders in their fields who bring an international perspective to information display. to assure that the events are complementary – with minimal overlap. The objec- Track 1: Display Marketplace tive is to establish a series of non-duplicative events such that delegates can easily v M-1: The Next Big Thing justify repeat attendance with the assurance of highly differentiated programs. v M-6: Display Market Trends High-Performance Displays: The 2013 SID High-Performance Displays Track 2: Mobile Displays Conference will highlight next-generation display technologies that offer v M-2: Advanced Mobile-Display Technologies significant opportunities to enhance the visual experience. The event will focus v M-7: Mobile Multimedia Displays on performance parameters, more so than the specific display technologies. The Track 3: Touch and Interactivity technologies necessary to promote improved performance will be highlighted. v M-3: Status and Future of Touch Technologies The event will enable delegates to consider various performance trade-offs M-8: Touch-Display Integration related to the future of vision-based devices. v Track 4: Liquid-Crystal Technology This event is a new event – but directly focuses on one of the biggest opportuni- M-4: Fast-Field-Switching (FFS) Mode and Its Applications ties for both display makers and device manufacturers – to truly differentiate v their product offerings. The event is expected to garner considerable interest v M-9: Fast-Switching Technologies for LC Devices toward Low-Power and discussion as various performance parameters are presented and compared. Display Systems Track 5: OLED Displays For further updates visit www.imsconferences.com/sidfti/html v M-5: Challenges of AMOLED TVs and Flexible AMOLED Displays v M-10: OLED Technology Track 6: Display Components and Metrology USINESS NTERPRISE USINESS SID B E (B v M-11: Optical Coatings and Films CONFERENCE AND INVESTORS CONFERENCE) v M-16: Display Measurement Basics and Practical Considerations Track 7: Lighting Business Conference: The 2013 SID Business Conference will be held on v M-12: Backlighting LEDs in General Illumination Monday, May 20, at the Vancouver Convention Centre. It will provide a unique v M-17: OLED Lighting forum where attendees will gain insight from leading minds from both Wall Track 8: 3D Technology Street and the display industry and focus on the theme “Paths to a Healthier v M-13: LC Technology for 3D Applications Display Industry.” Inspirational presentations from industry leaders and IHS v M-18: Signal Processing for Stereoscopic 3D Displays analysts will take an integrated view assessing the current health of the industry Track 9: Oxide TFTs and focus on what it would take to improve the health of the industry, identify- v M-14: Oxide TFTs: Technology Trends in Materials and Processes ing some specific exciting trends, and its impact on the display supply chain. v M-19: Device Structures and Stability of Oxide TFTs The Business Conference will feature keynotes and presentations from industry Track 10: Flexible-Display Technology leaders, lively panel sessions, and ample networking opportunities. v M-15: Flexible OLEDs for Display and Lighting Applications For further updates visit www.imsconferences.com/sidbc.html v M-20: A Critical and Current Review of the Present and Future Prospects for Investors Conference: Co-sponsored by Cowen & Co., LLC, a securities and e-Paper investment banking firm, this Conference, to be held on Tuesday, May 21, will For further details visit www.displayweek.org/Program/MondaySeminars feature company presentations from leading public and private display compa- nies, intended to appeal primarily to securities analysts, portfolio managers, investors, M&A specialists, and display company executives. NNUAL WARDS UNCHEON For further updates visit www.cowen.com A A L

The annual SID Awards Luncheon will take place at 12:00 Noon on Wednesday, 2013 SID SEMINAR SERIES May 22, in Room 301/305 of the Vancouver Convention Centre. This year’s luncheon speaker will be Prof. Ronald A. Rensink from the Departments of Computer Science and Sunday Short Courses Psychology at the University of British Columbia, Vancouver, The Society for Information Display presents four 4-hour short courses on diverse Canada. topics related to information display on Sunday, May 19. The tutorials are Professor Rensink will discuss “When Vision Science Met characterized by technical depth and small class size. The classes will cover the Information Display.” fundamentals of electronic information displays and will be held on the morning and afternoon of the Sunday preceding the Symposium. Full-color tutorial notes Also, the 2013 Display Industry Awards honoring the best will be distributed to all participants and are included in the fee. Ample time will of the industry in 2012 and the 2013 SID Best-in-Show be provided for questions from the audience. The speakers are leaders in their and I-Zone award winners will be announced. Also, the respective fields and bring an international perspective to information display. SID 2013 honors and award recipients will be acknowledged. S-1: Fundamentals of OLED Technology S-2: Fundamentals of 3D Computer Vision and Applications to Interactive Devices SPECIAL EVENT S-3: Fundamentals of TFT Backplane Technologies and Progress Made on Metal-Oxide TFTs S-4: Fundamentals of Touch Technologies The Vancouver Aquarium – Sponsored by Henkel For further details visit www.displayweek.org/Program/SundayShortCourses Come join us on this special event on Wednesday evening to the Vancouver Aquarium, the largest in Monday Technology / Applications Seminars Canada and one of the five largest in North America. The SID Technology / Applications Seminars to be held on Monday, May 20, The Vancouver Aquarium was the first aquarium in present lectures on diverse topics related to electronic information displays. These the world to capture and display an orca. For more seminars are tutorial in nature, and an attempt is made to provide information at details regarding the Vancouver Aquarium, please visit www.vanaqua.org 43 First LookPagesp42-43_Layout13/22/20139:51PMPage44

Display Week 2013 Overview Vancouver Convention Centre, Vancouver, British Columbia, Canada May 19–24, 2013

Sunday, May 19 Monday, May 20 Tuesday, May 21 Wednesday, May 22 Thursday, May 23 Friday, May 24 TIMETABLE Course Seminars Bus Conf Symp Exhibits Inv. Conf. Symp Exhibits MFC Symp Exhibits MFC Symp 7:45 AM - 8:30 AM SID Bus Mtg 8:30 AM - 9:00 AM Seminars 9:00 AM - 9:30 AM Welcome & Oral Oral M1 - M5 Oral Sessions 9:30 AM - 10:00 AM Keynote Addresses Sessions Sessions 60-64 10:00 AM - 10:30 AM 20-25 36-41

10:30 AM - 11:00 AM Business Oral Oral Seminars Conference Oral Oral Sessions 11:00 AM - 11:30 AM Sessions Sessions 44 11:30 AM - 12:00 PM M6 - M10 Sessions 65-69 S-1 & S-2 26-31 42-47 3-8 Exhibits/ 12:00 PM - 12:30 PM Short Courses Luncheon: Author Interviews 12:30 PM - 1:00 PM DIA & Bus. Conf.

1:00 PM - 1:30 PM Lunch Best-in-Show

1:30 PM - 2:00 PM Awards I-Zone Oral Seminars Sessions Exhibitors Forum Sessions 2:00 PM - 2:30 PM Oral Designated 2:30 PM - 3:00 PM M11- M15 48-53 Sessions I-Zone Exhibit 3:00 PM - 3:30 PM Touch Gesture Motion Market Focus Conference: Market Focus Conference:

9-14 Time Oral High-Performance Displays

3:30 PM - 4:00 PM Investors Conference Oral Oral Sessions 4:00 PM - 4:30 PM Seminars Business Conference Sessions Sessions Exhibits / Exhibitors Forum Sessions / 54-59 4:30 PM - 5:00 PM M16 - M20 15-19 32-35, 70 Auth. Inter. 5:00 PM - 5:30 PM Author Author Exhibits / Exhibitors Forum Sessions / . . 5:30 PM - 6:00 PM S-3 & S-4 Interviews Interviews Bus. nvest. Conf. Conf. Short Courses I Recept 6:00 PM - 6:30 PM Recept Poster 6:30 PM - 7:00 PM Session 7:00 PM - 7:30 PM 7:30 PM - 8:00 PM 8:00 PM - 8:30 PM 8:30 PM - 9:00 PM Awards 9:00 PM - 9:30 PM Banquet 9:30 PM - 10:00 PM First Look Pages p42-43_Layout 1 3/23/2013 10:37 PM Page 45

Display Week 2013 Symposium at a Glance

2013 SID Display Week Symposium at a Glance – Vancouver Convention Centre Times Ballroom A Ballroom B Ballroom C Room 118 Room202 Room 205 Times 8:00 – 10:20 SID Business Meeting and Keynote Session (Concourse Hall) 8:00 – 10:20

3 4 Autostereoscopic and Multi- 5 6 7 8 10:50 – 12:10 Oxide TFTs I 10:50 – 12:10 View I LCD or OLED? e-Paper I Plasma-Display Devices Emerging Displays

(Joint with Active Matrix) 21 May Tuesday, (Joint with Systems)

9 10 13 14 Autostereoscopic and Multi- 11 12 2:00 – 3:20 Oxide TFTs II Plasma-Display Protective Human Enhancement and 2:00 – 3:20 View II 4K x 2K Displays e-Paper II (Joint with Active Matrix) Layer Diagnostics (Joint with Systems) Tuesday, May 21

15 16 19 17 18 LC Technology for 3D I Oxide-TFT Reliability and Quantum- T3:40 – 5:00 3:40 – 5:00 Blue-Phase LCDs I Flexible AMOLEDs (Joint with Liquid Crystal) (Joint with Active Matrix) Dot LEDs

5:00 – 6:00 Author Interviews (Exhibit Hall) 5:00 – 6:00

20 21 22 23 24 25 9:00 – 10:20 LC Technology for 3D II OLED TV 9:00 – 10:20 Blue-Phase LCDs II Flexible TFTs Novel Measurement Topics Advanced LCD Electronics (Joint with Liquid Crystal) (Joint with OLEDs)

22 May Wednesday, 30 26 29 Challenges in 3D 31 Holographic and Volumetric 27 28 10:40 – 12:00 Flexible Barriers and Characterization, Motion High-Speed Driver 10:40 – 12:00 Displays OLED Displays I Advanced Displays Substrates Blur Analysis, and Monitor Technologies (Joint with Systems) Calibration

2:00 – 3:30 Designated Exhibit Time (Exhibit Hall) 2:00 – 3:30

70 Wednesday, May 22 32 Late-News Papers: 33 34 35 3:30 – 4:50 Light-Field Displays Flexible OLEDs and 3:30 – 4:50 OLED Displays II Fast-Switching LCDs OLED Pixel and Driving (Joint with Systems) Printing Techniques

5:00 – 6:00 Author Interviews (Exhibit Hall) 5:00 – 6:00

40 36 37 38 39 Automotive and Head-Up 41 9:00 – 10:20 Perception in 3D Displays 9:00 – 10:20 OLED Materials Film and Alignment Touch User Experience Displays (HUD) Colors and Image Quality (Joint with Applied Vision) (Joint with Projection)

46

42 44 45 OLED and Oxide-TFT 47 43 10:40 – 12:00 3D Algorithms and Driving Liquid Crystals with Touch Integration and Manufacturing Human Factors on Lighting 10:40 – 12:00 OLED Devices I (Joint with Systems) Reactive Mesogen Controllers (Joint with OLED, Active (Joint with Applied Vision) 23 May Thursday, Matrix, and Manufacturing)

52 48 50 53 49 51 Oxide-TFT Manufacturing 1:30 – 2:50 3D Applications Low-Power and Sensor- Lighting Designs 1:30 – 2:50

OLED Devices II Touch Applications (Joint with Active Matrix (Joint with Applications) Integrated Displays (Joint with Applications) and Manufacturing) Thursday, May 23

58 57 54 Advanced Substrates and 59 55 56 Touch Sensors, Materials, 3:10 – 4:30 Projection Screens Manufacturing on Flex Novel Backlighting 3:10 – 4:30 OLED Manufacturing TFT Applications and Manufacturing (Joint with Projection) (Joint with Systems (Joint with Manufacturing) e-Paper/Flexible)

4:30 – 5:30 Author Interviews (Exhibit Hall) 4:30 – 5:30

5:00 – 8:00 Poster Session (Exhibit Hall) 5:00 – 8:00

61 63 64 60 62 9:00 – 10:20 OLED Lighting I Mechanical Reliability Near-to-Eye, Transparent, 9:00 – 10:20 24 May Friday, Projection Light Sources TFTs for Mobile Display (Joint with OLEDs) Testing for Displays and Floating Displays

65 66 68 69 67 Friday, May 24 10:40 – 12:00 Projection-Display OLED Lighting II Advances in Materials for Energy-Efficient Displays 10:40 – 12:00 TFT Driver Circuits Components (Joint with OLEDs) Manufacturing (Joint with Electronics)

12:00 – 1:00 Author Interviews (Exhibit Hall) 12:00 – 1:00

TECHNOLOGY TRACKS KEY

3-D Active-Matrix Devices Applications Applied Vision Electronics Emissive e-Paper/Flexible Lighting Liquid Crystal Manufacturing Measurement OLEDs Oxide TFTs Projection Systems Touch

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symposium preview

Plan Ahead for the 2013 Symposium

Make the most of Display Week 2013 with an advance look at this year’s technology sessions.

by Jenny Donelan

HE Society for Information Display’s stellar line-up of keynote speakers (highlighted WRGB Pixel Design,” by Woo-Jin Nam annualT symposium is the foundation of Display throughout this article) on Tuesday morning of LG Display Co. and “Negative-Bias Week. Each year, hundreds of papers are pre- immediately before the exhibition opens. Photodegradation Mechanism in SnO TFTs,” sented that convey vital research and develop- The following session highlights are but a by Masashi Tsubuku of the Semiconductor ment information, both forward-looking and small portion of what awaits attendees at Energy Laboratory Co., Ltd. According to immediately practical, in numerous areas of Display Week 2013. Come join us to find out Nishibe, both these papers will address key display technology. The information you will what’s happened in our industry over the past factors for improving IGZO reliability. obtain at this year’s Symposium in Vancouver, year – and what’s going to happen in the years Canada, is not available at any other venue or to come. See you in Vancouver! Applications: Expanded Interaction, from any other industry organizations. Emerging Displays As in previous years, sessions are organized Active-Matrix Devices: Oxide TFT As is often the case in the applications sessions by subcommittees, whose members have Starts to Hit Its Stride at Display Week, this year’s papers cover an chosen the most exciting and informative Last year’s Active-Matrix Devices (AND) extremely wide range of topics. Of particular papers in their focus areas of display technol- sessions covered topics such as IGZO and note are two invited papers on “auditory” dis- ogy. Those areas include active-matrix 8K × 4K LCDs – providing advance notice of plays in the session titled Human Enhance- devices, applications, applied vision, display technology later shown in products at CES ment and Diagnostics. “Sonification: electronics, display manufacturing, display this year. The 2013 AMD papers will continue Multimodal and Auditory Display of Data,” measurement, display systems, emissive representing some of the most interesting and by Bruce Walker of the Georgia Institute of displays, e-paper and flexible displays, liquid- important news at the Symposium, according Technology, and “Development of Auditory crystal technology, OLEDs, and projection. to subcommittee chair Tohru Nishibe. Among and Cross-Modal Displays for Assistive Tech- In addition to these regular topics, SID has the most newsworthy, he says, are two invited nology,” by Tony Stockman of Queen Mary designated special display topics of interest presentations on oxide semiconductors. The University of London, describe displays that that are especially timely and important to our first is “Electronic Structure, Carrier Trans- both speak and listen (as well as display visual industry: OLED TV, oxide TFTs, 3-D, light- port, Defects, and Impurities in Amorphous imagery). They may thus prove useful to ing, and touch and interactivity. Attendees at Oxide Semiconductors,” by Toshio Kamiya of vision-impaired users, in addition to other Display Week 2013 have the opportunity to the Tokyo Institute of Technology. “This is a applications, notes subcommittee chair Adi gain comprehensive knowledge of each of good tutorial and basic analysis that includes Abileah. “The idea is that there is more than these special topics not only by attending the new findings,” says Nishibe. The second is one way to interact with displays,” says presentations during the four-day technical “Development of IGZO-TFT and Creation of Abileah. “We think this is a direction that symposium, but also through the special New Devices Using IGZO-TFTs,” by Hajime SID will head toward in the future.” Sunday Short Courses and Monday Seminars. Imai of Sharp Corp, in collaboration with SEL As is also usual for applications, there are SID also offers a display-centric business (Semiconductor Energy Laboratory Co.). too many interesting papers to cite here, but perspective with the Business and Investors “This look at the world’s first IGZO product one of note in the Emerging Displays session Conferences and the Market Focus Confer- [shown at CES] will attract a huge audience,” is the invited paper “Optical and System ences. In addition, be sure to catch this year’s says Nishibe. “Moreover, we’ll have intrigu- Considerations for Mobile Touch-Screen ing invited papers from LG Display, Samsung Applications,” by Steven Bathiche of Jenny Donelan is the Managing Editor of Display, and others.” Microsoft, which Abileah describes as an Information Display Magazine. She can be Other papers of interest are “A 55-in. excellent review presentation that will cover reached at [email protected]. AMOLED TV Using InGaZnO TFTs Using different considerations for mobile-display

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parameters including pixel density, optical cations. With that in mind, the Display Man- effects, ambient-lighting influence, touch- ufacturing subcommittee is highlighting three screen weight, and power. The paper analyzes papers from this year’s impressive selection. the significance of these parameters based on The first, “Ink-Jet-Printed 17-in. AMOLED the human eye’s acuity, contrast Display with Amorphous-IGZO TFT Back- sensitivity, and focusing ability in different plane,” by Ze Liu of BOE Technology Group lighting conditions. The paper “Semi-Trans- Co., is an invited paper that reports on the parent Inverted Quantum-Dot Light-Emitting successful integration of ink-jet processed Diodes,” by Jin Jang of Kyung Hee Univer- OLEDs with amorphous-oxide TFTs as a path sity, will describe a new display technology, a to cost-effective manufacturing of large-sized semi-transparent inverted quantum-dot light- panels. “It is very exciting to see this technol- emitting diode (QLED) that uses tri-layered ogy at the manufacturing stage,” says Sub- quantum dots. “Blur-Free Transparent LCD committee Chair Ion Bita. “BOE is a relative with Hybrid Transparency,” by Chia-Wei Kuo newcomer,” he says, “but their rapid advances of AU Optronics Corp., outlines a 65-in trans- in technology development and manufacturing parent LCD in which the author controlled LC are very impressive.” orientation to suppress image blurring behind The paper “Advanced Glass Substrate for the transparent LCD. the Enhancement of OLED Lighting Out- Coupling Efficiency,” by Nobuhiro Nakamura Dr. Kinam Kim, President & CEO, Applied Vision: Night-time TV of Asahi Glass Co., reports on a substrate Samsung Display Co., will give a Keynote Watching designed to improve efficiency in lighting and address on “Displays and Innovation: “This year there are a lot of Applied Vision with potential for display applications. This An Exciting Future” papers related to 3-D and lighting,” says sub- substrate incorporates a glass-scattering layer committee chair Yi-Pai Huang. “These are that greatly improves efficiency, as demon- the trends.” Two interesting invited papers is a larger number of papers from academia strated by the paper’s author using OLED from the joint session with lighting that rather than private industry. lighting panels. “Roll-to-Roll Process on address real practical marketplace issues are There is a full session focused on OLED Ultra-Thin Flexible Glass for Manufacturing a “Displays as Light Sources: Resolving the Pixel and Driving as well as interesting papers Multi-Touch Sensor Panel,” by Chia-Sheng Conflict between Gamut and Color Render- in other areas include “Capacitively Coupled Huang of ITRI, demonstrates the advantages ing,” by Lorne Whitehead of the University of 13.56-MHz Resonance-Controlled Wireless of roll-to-roll manufacturing on thin-glass British Columbia, and “Opportunities with Power Transfer System for e-Paper Modules,” substrates, in which the set of processes and LEDs for Increasing the Visual Benefits of by Reiji Hattori of Kyushu University, and equipment developed by the authors enabled Lighting,” by Mark Rea of the Rensselaer “ESD and EOS Impact During Module fabrication of ITO-pattern-based touch- Polytechnic Institute. Assembly Processes of Display Panels,” by sensor panels from 0.1-mm rollable thin One slightly different paper that Huang Ming-Dou Ker of the National Chiao-Tung glass. recommends is “The Impact of Watching Tel- University, both from the advanced LCD evision on Evening Melatonin Levels,” by Electronics session. Hattori’s paper describes Display Measurement: IDMS Gains Mariana Figueiro of Rensselaer Polytechnic a development that could enable electronic Traction Institute. For at least a decade, some paper that works without batteries. Ker’s As was the case for the last several years, 3-D researchers (and the media) have suggested presentation will address the phenomena of is a hot topic for Display Measurement in that night-time TV viewing suppresses human electrostatic discharge (ESD) and electrical 2013. This is because 2-D measurement just melatonin levels and thus interferes with overstress (EOS) as they occur in production doesn’t cover all of what needs to be meas- sleep. Figueiro’s paper investigated whether processes, as well as their effect on product ured in 3-D, explains subcommittee chair the blue light from television does in fact sup- reliability. He will suggest ways to control Frank Rochow. What is new in measurement press melatonin. Readers will have to attend ESD and EOS so as to improve overall papers this year is that authors have begun the session to find out the answer, as well as yield. adopting the IDMS, the display measurement the author’s recommendation. standard released in 2012 by the ICDM (Inter- Display Manufacturing: Timely national Committee for Display Metrology). Display Electronics: OLED Drivers Problem Solving “The IDMS methods are definitely being Lead the Pack Manufacturing is an exciting R&D focus topic implemented in the papers being presented,” The scope of papers in Display Electronics these days. We are witnessing doubled-down says Rochow. “The IDMS is being seen as a this year is diverse but very relevant, accord- efforts for solving manufacturing process and success and is widely respected.” ing to subcommittee chair Seung Woo Lee. materials challenges to enable the long-held A good paper to check out for the latest in “We do have many OLED-driving papers, but promise of OLED use in TVs, as well as to 3-D measurements is the invited “Techniques except for this area, the topics are widespread,” accelerate the adoption of oxide-semiconduc- and Challenges in the Measurement of Stereo- he says. One trend that Lee did note for 2013 tor TFTs for high-performance display appli- scopic Displays,” by Adi Abileah of Planar

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Systems. Another interesting paper that takes Integrated a-Si Gate Driver,” by Yen Lai. on the newest types of displays is “Viewing- This paper, highly recommended by the sub- Angle Measurements on Flexible Reflective commitee, describes how the authors devel- e-Paper Displays,” by Dirk Hertel of E Ink oped a prototype and concept design for what Corp. Displays that are curved and reflective they describe as the next-stage e-reader: make it difficult for researchers to obtain combining a flexible color electrophoretic repeatable, consistent measurements, explains display (EPD), flexible projected-capacitive Rochow. touch panel (TP), and amorphous-silicon gate driver circuit on array (GOA) technologies. Display Systems: Deep Views With nine separate sessions, Display Systems Liquid-Crystal Technology: Meeting has a lot going on this year. 3-D continues to the Challenges of a Changing Landscape be a popular topic, but within 3-D the types of The LCT subcommittee made a point of invit- displays have grown increasingly diverse. ing what chair Philip Chen describes as the This year’s 3-D sessions include Autostereo- major Asian companies to submit papers this scopic and Multiview I and II, Holographic year: Samsung, AUO, LG Display, Japan Dis- and Volumetric Displays, Lightfield Display, play, China Star, BOE, and others. The idea, and 3-D Algorithms and Driving. says Chen, was to get these companies to Other Display Systems sessions include come to Display Week to share their latest Mr. Bill Buxton, Principal Researcher, Augmented Reality and Near-to-Eye Displays, developments and plans for the future, thus Microsoft Research, Microsoft Corp., Novel Backlighting Systems, Automotive and providing symposium goers with a complete will give a keynote address on Head-Up Displays, and Energy-Efficient Dis- view of the LC landscape. “The Social Life of Devices” plays. Of special interest is the invited paper, Another subcommittee initiative was to “Augmented-Reality Head-Up Display for Car organize a session specifically on the topic of Navigation System,” by Toshiki Kaneko of YBO3 under Vacuum- Excitation,” OLEDs and LCDs. The three invited papers Japan Display, Inc., which uses a laser projec- by Anthony Diaz of Central Washington in the session titled LCDs or OLEDs? include tor and microlens array to create what the University, in which the author’s analysis “TFT-LCDs as the Future Leading Role in authors say is the first such display that creates suggests a correlation between electron-hole FPDs,” by Yasuhiro Ukai of Ukai Display augmented reality beyond the windshield. trapping efficiency and the energy of activator Device Institute;”AH-IPS, Superb Display for Another invited paper, “Extending Battery electronic states relative to the host conduc- Mobile Devices,” by Joun Ho Lee of LG Life of Ultrabook through Use of Panel Self- tion band. Display Co.; and “LCD or OLED: Who Refresh Technology,” by Kamal Shah of Intel The other two emissive sessions are Wins?,” by David Barnes of BizWitz. This Corp., describes an interesting new power- devoted to plasma. An invited plasma paper last, possibly provocative paper will discuss management technique for mobile devices. of special interest is “Progress in Luminous historical trends that point toward a future of Array Film with Plasma-Tube Technology for increasing technical performance and decreas- Emissive Displays: Lots of Late-News Seamless-Tiling Super-Large-Area Display,” ing financial performance for LCD producers, for Quantum Dots and Phosphors by Terukazu Kosako of Shinoda Plasma Co., as well as the feasibility of creating an OLED Probably the most intriguing aspect of the which discusses a new flat-sealing process infrastructure. “This will be a very attractive Emissive Display sessions this year are the that can enable extra-large curved displays. session,” says Chen, “for students and for number of late-news papers in the Phosphors The late-news paper “New, Thinner Phosphor anyone else in the industry who wants to and Quantum-Dot session – three out of a Layer Fabrication Process for ACPDPs,” by know about the future direction of these total of six. These are “Development of Ryuichi Murai of Panasonic AVC Networks technologies.” Stable Alkaline-Earth-Sulfide LED Phosphors Company, describes a process for achieving a Four more notable papers from the LC for LCD Backlights,” by Ravi Rao of 3-µm-thick phosphor layer in the PDP cells. sessions are “High-Transmission VA-LCD Specialty Phosphors, Inc.; “High-Efficiency with a Three Dimensionally Shaped Pixel and Long-Lifetime Quantum-Dot Light-Emit- e-Paper and Flexible Displays Electrode for 4K × 2K Displays,” by Masashi ting Diodes for Flat-Panel-Display Applica- The six e-Paper and Flexible Displays sessions Miyakawa of Sony Corp.;” “LC GRIN Lens tion,” by Paul Holloway of the University of this year include one composed entirely of Mode with Wide Viewing Angle for Rotatable Florida; and “How to Fabricate Much Brighter late-news papers on the topic of Flexible OLEDs 2D/3D Tablet,” by Masako Kashiwagi of AC Electroluminescent Lamps: Optimizing and Printed Electronics. These five papers, Toshiba Corp.; “Driving Method of FFS- the Alignment of the Emitting ZnS:Cu Phos- covering topics such as barrier films, ink-jet Mode Oxide LCD for Reducing Eye Strain,” phor Particles to the AC Field,” by Jack Silver printing, and plastic substrates, will obviously by Ryo Hatsumi of the Semiconductor Energy of Brunel University. According to the com- provide an exciting look at the state of the art. Laboratory Co.; and “A Nematic LCD with mittee, an exceptional paper in this session is A notable paper from AU Optronics is “A Submillisecond Gray-to-Gray Response “Characterization of Electron–Hole-Pair 9-in. Flexible Color Electrophoretic Display Time,” by Daming Xu of the University of Migration and Trapping in Rare-Earth-Doped with Projected-Capacitive Touch Panel and Central Florida.

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OLEDs: Big TVs and Better Materials doubt be among the most popular at the sym- One trend is certain: OLED TVs, at least posium. AUO’s 65-in TV (described in the OLED TV prototypes, keep getting larger. The OLEDs section above) will certainly be an most exciting OLED paper this year, accord- attention-getter, but the other three papers will ing to subcommittee chair Sven Murano, will be fascinating as well. Certainly, no one will be “Large-Sized Amorphous-Oxide-TFT want to miss “Technological Progress and AMOLED-TV Using Side-by-Side and Fine- Commercialization of AMOLED TV,” in which Metal-Mask Technology” by Jen-Yu Lee of author Chang-Ho Oh of LG Display Co. talks AU Optronics Corp. This paper describes a about the art and science behind getting the 65-in. panel with a long-range threshold volt- first mass-produced large-area OLED TVs off age uniformity of 0.34 V. The dam and fill the factory floor and into people’s living rooms. encapsulation process is simple and highly Oxide TFTs: A mere four years ago, the stable, according to the author. The AUO idea that oxide TFT could take the place of paper is part of a special all OLED-TV silicon in display devices was “very new and session (jointly offered through the OLEDs promising,”according to Hyun Jae Kim, the and Active-Matrix Devices committees) that 2009 Active-Matrix subcommittee chair. In Murano says may be among the hottest at the 2013, oxide TFT is now a special topic with symposium. five sessions devoted to it alone. Those are: There is more to OLEDs than big TVs, Professor John F. Wager, The Michael and • Oxide TFT I and II though. This year has brought many improve- Judith Gaulke Endowed Chair Professor of • Oxide TFT Reliability ments to OLED lighting technology (see the Electrical Engineering, School of EECS, • OLED and Oxide TFT Manufacturing Lighting section below), and also progress in Oregon State University, will give a keynote • Oxide TFT Manufacturing OLED R&D in general. One of the hurdles address on “Exciting Developments Several of the outstanding oxide-TFT that OLED technology needs to clear in order in Oxide-TFT Technology” papers have been described above in conjunc- to realize its full commercial potential is effi- tion with other technology topics such as ciency in both materials and devices. Two Active-Matrix Devices and Display Manufac- very interesting papers that address this aspect A standout invited paper in the Projection turing. An additional paper to take note of is are “Highly Efficient OLED Device with sessions that Sobel recommends is “High- “Electrical Properties of Amorphous InGaZnO Device Architecture for Reducing Drive Volt- Efficiency Polarization Preserving Cinema TFTs Prepared by Magnetron Sputtering age,” by Yoshiharu Hirakata of Semiconductor Projection Screen,” by Dave Coleman of Using Kr and Xe Gas,” by Tetsuya Goto of Energy Laboratory, which describes how the RealD. This paper describes a polarization- Tohoku University. Goto’s work explains author’s team developed phosphorescent preserving projection screen that addresses how the use of certain noble gases in the mag- OLEDs with high efficiency, a long lifetime, issues of conventional silver screens through netron-sputtering part of the manufacturing and low drive voltage using energy transfer substantially increased efficiency (brightness), process can reduce film damage caused by from an exciplex to an emitter; and “Efficiency increased stereo contrast, larger viewing ion-bombardment, and thus improve overall Improvement of Fluorescent Blue Device by angle, and matte appearance. In addition, thin-film quality. Molecular Orientation of Blue Dopant,” by the screen enables vastly improved laser- 3-D: This technology area continues to be Hitoshi Kuma of Idemitsu Kosan Co., Ltd. speckle reduction. Says Sobel, “This is extremely well-represented in terms of paper Kuma’s research suggests how phosphores- potentially a game changer, a big curved submissions – there are 10 3-D sessions in this cent blue devices, which have lagged behind screen for digital cinema, with better perform- year’s symposium – but the subjects have their red and green counterparts in terms of ance, wider angles, [reduced] ghosting. It evolved over the past few years from discus- efficiency, can be made to catch up. will be more expensive than conventional screens.” sions on passive vs. active glasses to a wide Projection: Lasers Loom Larger range of 3-D displays. The 3-D sessions are Last year, subcommittee co-chair Alan Sobel Special Topics: OLED TV, Oxide TFTs, • Autostereoscopic and Multi-View I and predicted that 2012 would be the year of the 3-D, Lighting, and Touch & II pico projector, in terms of commercial avail- Interactivity • LC Technology for 3D I and II ability. That seems to be true, based on a Each year, the Society for Information Display • Holographic and Volumetric Displays quick online search for the products, which designates special sessions to explore impor- • Light-field Display are numerous and available in some cases for tant and timely display topics. This year’s • Perception in 3D Display less than $200. In terms of the symposium, sessions are OLED TV, oxide TFTs, 3-D, • 3D Algorithms and Driving however, the technology is mature. “Surpris- lighting, and touch & interactivity. Here are • 3D Application ingly, there are no [LED-based] pico-projector highlights from each: • Projection Screens papers this year,” says Sobel. Instead, laser- OLED TV: The four papers in this one Some of the outstanding 3-D papers are light engines for projection are the focus of session, jointly sponsored by the Active-Matrix outlined in the sections above, such as several papers. Devices and OLEDs subcommittees, will no RealD’s curved cinema screen described

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under Projection. Here are some additional White OLEDs with Over 100-lm/W for • Touch Sensors, Materials, and Manufac- ones to check out: “High-Performance General Lighting,” by Kazuyuki Yamae of turing Autostereoscopic 2D/3D Switchable Display Panasonic Eco Solutions. The author’s high- A touch paper of note is “12.2-in. 1920 × Using Liquid-Crystal Lens,” by Shinichiro performance all-phosphorescent white devices RGBW × 720 IPS-LCD Integrating In-Cell Oka of Japan Display, Inc., describes the on a light-outcoupling substrate showed an Touch Panel for Automotive Use,” by Chihiro development of a switchable 2D/3D display efficacy of 114 lm/W at 1000 cd/m2 and 102 2 Tanaka of Japan Display, Inc., which suggests with higher luminance and reduced crosstalk. lm/W at 3000 cd/m . solutions to some of the special issues sur- Late-news paper “Real-Time Up-Converter According to Sven Murano, this year’s rounding the design of an in-cell touch panel from HDTV to 4K with Super-High Resolu- OLED subcommittee chair, “Now is the time specifically for automotive use. An interest- tion,” by Seiichi Gohshi of Kogakuin Univer- when [lighting] companies are starting to ing paper that addresses the touch user experi- sity, suggests a method for obtaining invest in manufacturing lines, and I am opti- ence is “The Need for Speed in Touch Systems,” high-quality 4K resolution from HDTV video, mistic that in the coming years OLED lighting by Albert Ng of Microsoft. The author shows a subject that will become increasingly rele- will become cheaper and its efficacy will go the impact of touch-to-display latency, frame vant in the months and years to come. up.” rate, and motion blur on the touch-user experi- Lighting: There are four lighting sessions Touch and Interactivity: Tighter integra- ence. He explains how by using a custom this year, two of them devoted to OLEDs: tion and reduction of cost are two major issues device his team was able to achieve latencies • Human Factors on Lighting surrounding touch in display design and man- down to ~1 msec, with frame rates up to • Lighting Design ufacturing, according to Touch & Interactivity 1000 Hz. • OLED Lighting I and II chair Jeff Han. (Earlier this year, Han gave OLED lighting still has far to go in terms of the keynote address for the Bay Area SID A Wealth of Information manufacturing costs, efficiency, and lifetime, Chapter’s one-day technical conference, In sum total, there is no doubt that this collec- but progress is being made. One paper that Display and Touch Technologies of the tion of symposium papers represents the most describes a good advance is the invited “80- Future.) “Touch is still expensive,” says Han, important display industry information you lm/W White OLEDs for Solid-State Light- also noting that the touch user experience is will find all year. Please join the Display ing,” by Jaemin Moon of LG Chem. These also increasingly crucial. This year there is a Week presenters as they share their research OLEDs were realized by introducing a three- session devoted just to the user experience, with their friends and colleagues in the dis- n stacked tandem structure in conjunction with and three others as well: play industry. an internal light-extraction layer. Another • Touch User Experience exciting paper in terms of getting closer to • Touch Integration and Controller commercial viability is “Highly Efficient • Touch Application

J O I N S I D We invite you to join SID to participate in shaping the future development of: Display Week 2013 • Display technologies and display-related products SID International Symposium, • Materials and components for displays and Seminar & Exhibition display applications • Manufacturing processes and equipment May 19–24, 2013 • New markets and applications Vancouver Convention Center In every specialty you will find SID members Vancouver, British Columbia, Canada as leading contributors to their profession. http://www.sid.org/Membership.aspx www.displayweek.org

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SOCIETY FOR INFORMATION DISPLAY NEWS a hardware division with a mission to seed sequential color rendering to also greatly SID Bay Area Chapter Hosts a interactive large-screen displays into every expand the boundaries on color and produce Glimpse into the Future of possible application, not just conference high-dynamic-range displays. These methods rooms and presentation arenas. are much more achievable on consumer Displays Repeating a mantra we all know well, Jeff displays today due to the very low cost of stressed that there is no perfect touch technol- high-performance processors and the new by Stephen P. Atwood ogy for all applications. In fact, Jeff standards coming for digital-content distribu- explained that in his view, “Touch is not as tion. Of course, mentioning field-sequential The flyer headline read: “SID Bay Area good at content creation [as other methods],” topics invokes fear in technologists used to Announces First One-Day Technical Confer- and he went on to show some great demon- dealing with color-breakup artifacts and poor ence: Display and Touch Technologies of the strations of how the future will be focused on user response. Well, not to fear, because as Future: Jan 16, 2013.” So, there I went to pen and touch working together. For example, Candice described, the display area can be attend the first of what I sincerely hope will in a large-screen application, you might use segmented into small zones where each zone be an annual event, held in one of the most your left hand for manipulation of the docu- has its own color map and usually much lower fertile technology innovation regions in the ments and windows and your right hand to color-diversity requirements that, in turn, can world. The program was expertly arranged by draw and write the content. be met with virtual primaries (mixes of the conference co-chairs Jennifer Colegrove and Modality is also a big problem for touch actual primaries) that are much less saturated Rashmi Rao, and I was expecting a small applications – it’s challenging to program the and therefore less likely to produce color gathering of about 50 or so die-hard display computer to know what you intend when you breakup in observers. folk. What I encountered instead were over use your fingers. However, we can use tools Professor John F. Wager from Oregon 160 attendees, a virtual sell-out, representing to define modality, such as pens for inking State University took the podium next and 43 different technology companies and count- content and hands for manipulation. In a presented the technical merits and future less different product and display-application good UI design, your hand should be able to potential of oxide thin-film transistors (TFTs) interests. What unfolded throughout the day rest on the screen while you are inking and for a variety of display applications, especially was a wonderful balance of speaker presenta- you should be able to perform a variety of where transparency is needed. This is new tions, audience questions, panel discussions, content creation and context management technology that is just beginning to appear in and informal interactions that surely sparked tasks with no modality switching involved. mainstream OLED and LCD panels, promis- some fresh ideas and seeded some new energy This is part of what Jeff is working on at the ing a host of advantages and performance back into our industry. Microsoft Research Center and it is surely a improvements. The first published work on Keynote speaker Jeffrey Han (Fig. 1) talked glimpse of what we’ll see in Microsoft prod- oxide TFTs appeared in 2003 and serious about his background at Perceptive Pixel, the ucts someday soon. interest developed around 2007. TFTs made company he founded. He described how his In the LCD Technology session, we heard from oxides are accumulation-mode devices, effort to create new touch-screen hardware from three speakers whose endeavors and where electrons flow source to drain with quickly became an endeavor to expand the those of their companies are all making funda- positive gate voltage and positive drain voltage. potential of multi-touch through software as mental contributions to the field. Candice Making an oxide TFT with good mobility is he realized how little capability existed in user Brown Elliott, founder of first Clairvoyant challenging because unlike silicon, you want interfaces at the time. Now that Jeff as well and now Nouvoyance, companies dedicated to to discourage polycrystalline structures in as his company are part of the Microsoft innovative ways of producing multi-primary favor of amorphous. This is because of an Office organization, Perceptive Pixel remains color with improved power efficiency and effect called “carrier trapping,” which causes visual performance, presented her vision of an overall reduction in mobility in polycrys- key technology trends that are changing the talline states. However, some combinations landscape of color displays. “Thank goodness of elements such as zinc-tin (ZnSn) can be we’re moving to 4K resolution displays,” she made amorphous rather than polycrystalline. began, talking about all the experiential Today, we see great success using InGaZnOx advantages that users will gain from the ultra- (IGZO,) which is now in commercial use and high-definition formats. She then made a is described in several ID magazine articles of compelling case for the adoption of multi- late. primary display formats such as red-green- The key advantages of oxide TFTs for LCD blue-yellow-cyan, which allow a variety of manufacturing include high mobility, fast color metamers and creative ways to process refresh, and easy insertion into already exist- and render images with wider color ing a-Si plants. By contrast, poly-Si fabrica- while avoiding increases in energy require- tion requires a totally new plant, while oxide Fig. 1: Conference organizer Rashmi Rao ments. technology needs more of an upgrade. Oxide- and Perceptive Pixel Founder Jeff Han She then explained how local dimming – TFT technology promises to spread into demonstrate the large-area multi-touch using segmented 2-D backlights that enhance AMLCDs, EPDs, and AMOLEDs. It’s not yet Perceptive Pixel touch screen. dynamic range – can be augmented with field- ready to become part of flexible displays, but

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to read about progress being made in this area, believes that nozzle printing will be the talked about before at conferences and in ID, see the article “Oxide TFTs for AMOLED approach chosen most often in future because but I was convinced that significant progress TVs” in this issue. Also, see Fig. 2, for a of inherent advantages with the nozzles’ high is being made, and it’s inevitable that we will comparison. printing rates of 2–5 m/sec and scalability. see this technology in lighting applications in Rounding out this trio of speakers was Seth Up next was Sean Xia, a research manager the not too distant future. Coe-Sullivan, CTO and co-founder of QD with Universal Display Corp., who discussed While UDC has been working on large-area Vision, a company well known for its work in the short- and long-term potential for phos- OLEDs, Amal Ghosh and his colleagues at quantum-dot research, especially by those of phorescent OLEDs (PHOLEDs). Xia and his eMagin Corp. have been working on OLED us in the Northeast U.S. Seth discussed his team believe PHOLED materials hold the key microdisplays, packing more and more active- company’s newest innovation, which involves to a variety of new innovations in displays as matrix RGB pixels onto silicon backplanes LCD color-gamut-enhancing films with well as lighting applications, owing in large with display diagonals in the range of from quantum-dot technology that can be installed measure to the potential advantage in internal 0.5 in. to about 0.9 in. Their most stunning directly into edge-lit backlights. This technol- quantum efficiency (IQE) of up to 4× that of achievement is a 0.86-in.-diagonal WUXGA ogy uses blue LEDs and then converts the fluorescent OLEDs. This higher optical effi- microdisplay with an astounding 7,138,368 blue-light energy into very specific spectrums ciency naturally reduces heat dissipation in RGB pixel elements on it. This translates into of red, green, and blue as desired. QD Vision the devices and allows many more creative a pixel pitch of about 9.6 µm, with each sub- calls this technology “Color IQ,” and it was design concepts than current lighting tech- pixel having dimensions of 3.45 × 8.5 µm. jointly announced with Sony at CES as the nologies. Of course, there are numerous The application enables full HD 3-D glasses innovation behind Sony’s new “Triluminous” advantages to both inorganic as well as that can be used to create a virtual display Displays. The result is what Seth describes as organic LEDs for lighting, including wide experience. With the prototype the people “LCDs with OLED color gamuts.” Seth went color gamuts and high optical efficiency, but from eMagin discussed, the diagonal field of on to explain that another advantage of quantum OLED and particularly PHOLED materials view was 65°, creating a virtual image of dots is that they have worldwide environmental can be printed in large sheets and on many approximately 212 in. on the diagonal at 12 ft. compliance, containing no materials that are types of flexible substrates while achieving with a luminance of over150 cd/m2. Because known to be hazardous to the environment. In tested performance up to 70 lm/w for 30,000 it is OLED technology, it has a very fast the first embodiment, Color IQ is packaged in hours or longer. OLED lighting has been intrinsic response time and therefore can a polymer film, but in the future quantum dots might be suitable for inclusion in the LED package itself, eliminating the need for an additional component. This could represent a sub-$100 solution to the panel designer. AMLCDs However, there are further development Property a-Si:H LTPS IGZO challenges, including increasing total light proven, Manufacturability mature, proven emerging output, managing heat, and improving life- scaling issues times. Earlier QD optical performance used to degrade significantly at temperatures above Microstructure amorphous polycrystalline amorphous 80°C but now is within ±3% up to 140°C.

The currently expected lifetimes are greater VT uniformity good fair good than 2500 hours at power densities up to 100s 2 of W/cm with no measureable luminance VT stability poor excellent good... decay. Seth also believes that while the dots themselves are currently made in “batches,” Mobility 1 20–100 10–30 the process itself is completely scalable to high-volume LCD manufacturing. Mobility uniformity good fair good The next series of presentations focused on OLED technology, leading off with Dennis Device type NMOS CMOS NMOS Kondakov, Principal Scientist at Dupont. Dennis, who compared two options for depo- Process complexity low high low sition of OLED materials onto backplanes during OLED manufacturing – evaporation with masks or solution printing and process- ing. Major considerations in selecting one of Fig. 2: John Wager presented this slide comparing the relevant properties of a-Si, low-tempera- these processes include material waste and ture polysilicon (LTPS), and IGZO for AMLCD TFT fabrication. Credit: John F. Wager, panel size because OLED materials are very “Amorphous Oxide Semiconductor Thin-Film Transistors for Display Applications,” presented expensive and processes must scale effec- at the Bay-Area SID Chapter’s One-Day Conference on “Displays and Touch Technologies of tively to very large substrate sizes. Dupont the Future,” Sunnyvale, CA, January 16, 2013.

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deliver full 3-D stereo images without , sales of Windows 8 have not been encourag- the sensors and transducers moved to the back motion blur, or image latency. And, of course, ing, Geoff said there is a lack of hardware of the glass. Until recently, the touch market Ghosh promised they are also working on 2K that fully enables the new features and that was predominantly a commercial and indus- × 2K imagers and beyond. Windows 8 will soon drive the consumer market trial application space. As we know, begin- By this point, you might think we have as hardware catches up. He also predicted ning around 2000, the consumer touch market already covered a full day but, in fact, all the that by 2018, 95% of phones will be touch began its expansion way beyond the commer- above was presented before lunch! The after- enabled – something I’m not at all surprised cial market. This is important because the noon sessions began with a keynote from about. Recently, the concentration of touch in user’s learning curve in the two markets is Achin Bhowmik, Intel’s Director of Percep- some notebook formats such as All-in-Ones very different. Consumers will make the tual Computing, who characterized the major (AiOs) actually went down due to fears of effort to learn how to best optimize their weakness of computers today as their limited pro-cap-only choices for Windows 8 – not personal devices, but commercial market ability to interact with humans. Although the because the market doesn’t exist. Similarly, users are transient and will not invest time to human brain has a much slower processing with traditional “clamshell” notebooks, learn; therefore, the touch interface and appli- speed than even the slowest computers, it can increasing touch penetration will require solu- cation experience must still be significantly perform massive amounts of parallel process- tions that are easier or more convenient than different. Examples Kent cited included an ing on multiple sensor inputs at the same time, alternative input methods and, of course, airport check-in kiosk vs. a smartphone. creating a much broader range of analytical Windows 8! Rounding out the trio of touch technology abilities than computers. Intel’s focus is to Meanwhile, Geoff said that large-format speakers was Zachi Baharav, Manager of bridge that gap in a series of steps, starting by touch has huge opportunities, and there are a R&D from Corning. We’re all familiar with enabling touch interfaces in all forms of number of technology options on the market the significant and highly innovative role tablets and handheld devices. or coming to market soon, including: camera- Corning has played in the LCD industry for As touch and Windows 8 become perva- based, vision-based, FTIR, projected-capacitive the last 30+ years, but it was interesting to sive, Intel envisions moving to the next level (Pro-Cap), “traditional” infrared, and high- hear how diverse and nuanced the company’s with a system it calls “Perceptual Computing,” finger-count multi-touch infrared. All of these offerings are for touch-sensor development. which is powered by a multi-input 3-D camera are in various stages of development or deploy- The diversity in touch-application require- system and an SDK that Intel is currently ment now. Not surprisingly, Pro-Cap is the ments varies in strength, thickness, chemistry, offering for free in beta form. This SDK biggest show in town, capturing 83% of the tolerance to processing, surface texture, etc., supports several perceptual modes, including market for screen applications less than in much greater degrees than we might have Close-Range Interactions, Hand and Finger 15 in. and spawning a number of R&D efforts realized. Baharav brought with him some of Level Tracking, Face Analysis, Tracking and on core materials such as metal mesh, silver the best Corning videos, including the famous Recognition, Speech Recognition, and 2-D/3-D nanowires, carbon nanotubes, and conductive “A Day Made of Glass.” Famous for their Object Tracking. As Bhowmik said, this new polymers. However, as Geoff explained, it’s imaginative depictions of transparent tablet approach “opens a world to creating applica- really the process to manufacture these screens displays and augmented reality, these videos tions without developing underlying controls.” that determines cost and performance improve- pose many interesting questions about user You can see an interesting demo of these new ments. With the OEM cost of a 13.3-in Pro-Cap interaction as well as future modalities for concepts at http://software.intel.com/en-us/ screen in the range of $55–85, there have information devices. They are, incidentally, vcsource/tools/perceptual-computing-sdk clearly been many improvements recently. also available on youtube but they are more These demos are more interesting than any- The other trend that Geoff emphasized was fun to watch on the big screens at a confer- thing I can write about here in a short space. renewed interest in stylus input. Windows 7 ence like this one. Clearly, we have seen for several years was finger-focused because of the perceived The final round of talks addressed flexible increasing interest all over the industry in new failure of stylus input on tablet PCs. How- displays and emerging technologies. Jennifer types of 3-D and non-contact interaction ever, several recent products have brought Colegrove, President of Touch Display modes with computers. Many concepts have back the stylus, which is much better for con- Research, spoke about the opportunities for recently been discussed at Display Week pre- tent creation such as drawing and writing, so continued technical advances in technologies sentations, some built on the Microsoft Kinect Window 8 will likely re-energize stylus input. and commented on the future potential. She platform. In fact, Intel’s product is compati- In fact, the ideal embodiment on larger said that there are “currently over 10 different ble with the Kinect device as well as its stan- screens may be just what Jeff Han discussed technologies that can be made into flexible dard depth camera offering, but the Intel SDK earlier: hand recognition for control of frames displays.” She went on to make a bold predic- focuses on hands and faces rather than the and windows and simultaneous stylus input tion that we will see a “…flexible AMOLED entire body. “If we want computers to be for actual content creation. from Samsung in 2013 that will be a phone interactive with people, we need to give people Next in line was Joel Kent from Elo Touch- and a tablet combined, with a screen size the tools to communicate with them,” said Systems to explain how surface-acoustic- >5 in.” That certainly got my attention! The Bhowmik in closing. wave (SAW) technology may be seeing a market revenue for flexible displays in 2011 Next, we heard from well-known industry rebirth. He explained his company’s new was a modest $400 million (which is larger expert Geoff Walker, who spoke about the edge-to-edge SAW implementation, which than I would have even thought), but Jennifer future of touch technology. Noting that early can produce a virtually bezel-less design with predicts by 2015 that it could be as much as

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• More advanced and efficient interaction between people and their devices. • A wider range of power-efficient, lower- cost, and even flexible devices going way beyond what we have today. • Displays becoming more fully integrated into all our appliances and devices, with virtual linkage creating a seamless envi- ronment for information exchange. • And best of all, a wide range of new opportunities for invention, discovery, investment, and future careers. I really enjoyed my trip to the future and it was all due to the outstanding efforts of the BA chapter conference team pictured in Fig. 3. Congratulations to them all for a very successful conference! n

VISIT INFORMATION DISPLAY ON-LINE Fig. 3: Bay Area SID Chapter Conference Organizers. From left to right in back row: Joel Pollack, Steven Huang, and Cheng-Wei Pei; from left to right in front row: Carolyn Marsden, www.informationdisplay.org Jennifer Colegrove, Rashmi Rao, John Miller, and Geoff Walker.

$2.5 billion Some of the key technology areas that are ripe for further development include OLED flexible barrier layers, color for e-Paper, ITO replacement materials, flexi- ble touch, and better/smaller batteries. The last speaker was Jian Chen, VP of R&D for Nanosys, a former winner of SID’s pres- tigous Display Industry Awards. Dr. Chen explained that green LED efficiency was one of the factors limiting adoption of RGB LED backlights. Also, differential aging made it hard to maintain white balance over long product life cycles, which explains why phos- phor white LEDs have become the de-facto standard for most LED backlight designs. Nanosys provides a film for LCD backlights it Display Week 2013 calls QDEF, which produces a secondary light emission with quantum-dot technology. These films can be tuned to very specific light wave- SID International Symposium, lengths based on stimulation from 365-nm blue LED sources. Nanosys has demonstrated its Seminar & Exhibition process to be very scalable with modest invest- ment, allowing it to partner with companies such May 19–24, 2013 as 3M to produce a roll-to-roll manufacturing process. This ensures the product can meet the demands of major LCD-manufacturing customers. Vancouver Convention Center While a great many seemingly diverse top- ics were covered during the course of this Vancouver, British Columbia, Canada event, it was clear that they all fit together when you step back and try to envision the www.displayweek.org characteristics of display technology several years into the future:

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continued from page 2 continued from page 4 Thank You” for everything they have respected for their accuracy. Needless to say, support the idea of abrupt transition are the achieved. oxide-TFT technology plays a large role in his optimists who believe that the current manu- Our lineup of technical articles was devel- view of the future. facturing issues will be solved within 2–3 oped for us by our two outstanding guest One application that Paul believes creates a years, as many companies shift to OLED-TV editors this month. The OLED articles were unique opportunity for OLED technology is manufacturing. The gradual transition sce- solicited by H. K. Chung, who led Samsung’s flexible displays, and so we asked another nario stems from the consideration that the OLED R&D for over 10 years and now is frequent contributor, Dr. Jason Heikenfeld, LCD TV will continue to lead the market Chair Professor at Sungkyunkwan University. Associate Professor at the University of because it will take more than 2–3 years for You can read his Guest Editor’s note to see Cincinnati, to look at the state of the art in OLED TV to establish a manufacturing tech- what his thoughts are for the future of OLED flexible displays for our Enabling Technology nology with both low cost and high yield. TVs and related developments. Our first feature that Jason decided to call “Flexing and Besides, the LCD-TV infrastructures have Frontline Technology article comes from Stretching.” Looking back as well as looking already been well established. In my opinion, author Jang Hyuk Kwon from the Department forward, Jason shows us where the most the entry of OLED TV into the marketplace of Information Display, Kyung Hee University, promising work is happening, the key oppor- will be driven by the marketing strategy of Seoul, Korea. All color flat-panel displays tunities for future innovation, and also names TV-set makers more than by the economy in utilize some form of color subpixel matrix to companies to point out specific embodiments the early phase, and the transition could be produce mixed colors and Dr. Kwon describes of each key infrastructure component. From swift because I believe the learning curve for the prevailing methods for patterning the color Jason’s description, which will also likely be large-OLED-panel manufacturing will be filters and/or emitters for those subpixels in updated at his seminar at Display Week in quicker than that for the small mobile display. his work titled “RGB Color Patterning for May, it’s clear organic electronics, specifically n AMOLED TVs.” OLEDs, will play a major role in the future of Next, we have our second Frontline Tech- flexible displays. Ho Kyoon Chung led Samsung’s OLED R&D nology feature titled “Oxide TFTs for There were a lot of headlines from this for over 10 years and is now Chair Professor AMOLED TVs” by author Jin-Seong Park, a year’s Consumer Electronics Show, including at Sungkyunkwan University after retirement professor at Hanyang University. Dr. Park a dazzling keynote by Samsung incorporating from Samsung. He is still continuing his explains the reasons why oxide TFTs are so a new phone concept presented by our own research on core-technology development for potentially important for OLED TVs, as well SID President Brian Berkeley. If you were flexible AMOLED and OLED lighting on as the current state of the art and some of not one of the reported 150,000 people who flexible substrates. He is a Fellow of SID the remaining hurdles in the way of mass- were there, worry not, because we asked and can be reached at [email protected]. producing oxide-TFT backplanes. Oxide industry reporter Steve Sechrist to give us TFTs have turned out to be one of the big “Alpha and Omega: Most Exciting Display stories thus far this year, especially when Technologies at CES.” Not surprising, if you linked to the future of OLED displays. Guest have been following our recent issues of ID, Editor Dr. Arokia Nathan brought us a great was that the major themes were ultra-high- article by Yan Ye from Applied Materials definition (UHD) TV, OLEDs, oxide TFTs, describing the underlying physics and proper- 3-D, and even transparent LCDs, which I ties of oxide TFTs. In his article, “Zinc think have a lot more potential than others Oxynitride TFT: Toward a New High-Mobility may recognize. In any case, there is plenty Low-Cost Thin-film Semiconductor,” we for everyone to get excited about in this show learn much about the different types of possi- review from Steve. ble oxide compounds that are candidates for And so, with this issue finally complete and J O I N S I D TFTs and why the amorphous state is actually ready for your enjoyment, I hope I’ll see all of We invite you to join SID to participate in better for mobility than the polycrystalline you in Vancouver in less than 2 months from shaping the future development of: state. This is a very detailed article that really now. I want to thank our tireless staff, our • Display technologies and display-related filled in the blanks for me about the current guest editors, and all our authors for their products state and future potential of this technology. dedicated work on this and every issue. n In this issue’s Display Marketplace feature • Materials and components for displays and titled “AMOLED Production: Entering a New display applications Era” contributing editor Paul Semenza has put • Manufacturing processes and equipment a great deal of effort into detailing the current state of AMOLED manufacturing, the varying • New markets and applications pixel architecture approaches companies are In every specialty you will find SID members pursuing, and the likely forward paths these as leading contributors to their profession. same companies will follow. Paul is not afraid to name names, and both his industry http://www.sid.org/Membership.aspx insight and technical understanding are widely

Information Display 2/13 55 ID Ad Index p56_Layout 1 3/28/2013 9:31 AM Page 56

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