On the Frontlines of Innovation:  Inspiration for “Skin-Like” Displays

Get Ready for Another Form-Factor Revolution

by Ruiqing (Ray) Ma

I love reading Information Display because I can conveniently get the industry and commercial information that I will never find by reading techn

I attended my first SID conference almost 20 years ago at the Walt Disney World Dolphin Hotel in Orlando.  I still remember the first time I wandered out of the hotel during a session break.  While walking along the palm-tree-covered walkway, admiring the 257-ft.-tall triangular tower and the two 56-ft.-tall dolphin statues atop the 12-story rectangular main building, breathing in the fresh tropical air blowing over a vast blue-colored lagoon, I was suddenly struck by a grand man-made white sandy beach in the middle of inland Florida – it was magical.

There was also something magical about the early 1990s for the display industry.  It was a time when the flat-panel industry was just beginning to take off, and we enjoyed annual double-digit revenue growth and fast-paced innovations in both technology and application.  The driving force behind this FPD revolution was mobility – effectively reducing the physical dimensions of displays from 3-D to 2-D.  Notebook computers and portable consumer electronics demanded a thin form factor from displays.

Fast forward to today, as the same force, mobility, is driving the next wave of the display revolution.  This is happening in front of our eyes.  The advancements in ICs, software, and wireless communications technologies enable us to do practically anything, information-wise and communication-wise, with devices small enough to fit into our pockets.  However, as the trend in recent years clearly indicates, we as human beings want to see larger and higher-quality images (does anyone still remember the size and resolution of the display on your first smartphone?).  How do you put a large display in a small device?  Well, another display form-factor revolution, from rigid to flexible, will do just that.

In this special issue on Flexible and Wearable Technology, we have prepared three excellent articles to report the current status of flexible AMOLED technology, and, equally important, the efforts being made to tackle the first applications that will jump-start the flexible revolution.

A flexible display needs to exist as part of an overall device.  Choosing and designing the first device to highlight the benefits of a flexible display is as important as developing the technology.  In the first article, titled “Technologies for Flexible AMOLEDs,” Dr. Soonkwang Hong and his colleagues at LG Display report their efforts in addressing various technical challenges to successfully bring the world’s first flexible OLED display to mass production in 2013, with the G Flex smartphone.  Even though the device did not take full advantage of the flexibility of the display, it was a significant milestone for flexible displays and was recognized with an SID Display Application of the Year Gold Award in 2014.

Researchers at ITRI believe that a tri-fold AMOLED display better represents a killer application for flexible displays.  As explained in the second article titled, “Foldable AMOLED Development: Progress and Challenges,” by Drs. Jing-Yi Yan, Jia-Chong Ho, and Janglin Chen, a tri-fold configuration enables the functionality of a smartphone and a tablet in the same device.  In the article, the authors explain in detail the challenges in achieving a folding radius of 5 mm or less and report the successful demonstration of AMOLED displays with folding radii of 5 and 7.5 mm, and in different folding modes, including the tri-fold mode at Touch Taiwan 2014.

Finally, we come to wearable devices.  I asked experts at Plastic Logic to help us better understand wearables by answering the following questions: (1) what are wearable devices; (2) what are the display requirements for wearable devices; and (3) what can flexible displays offer to wearable devices?  In the article titled, “OTFT Can Unlock the Potential of Wearables,” Dr. Paul Cain and his colleagues not only provide answers to my questions (check out their solution for battery life), but also report their work on flexible AMOLED displays using organic thin-film-transistor (OTFT) backplanes for wearable applications. At Display Week 2014, they demonstrated their TFT array that can be curved around a 250-μm radius (i.e., around a matchstick) with no change in transistor performance.  They believe that OTFT offers unrivaled levels of flexibility for AMOLED and represents an opportunity for designers to bring completely new types of user experience and utility to the world of wearable electronics.

I believe these three articles provide a good idea of the current status of flexible AMOLEDs in both technology and application development.  Of course, we still face challenges, as explained by all three articles, and will continue to do so.  But if there is anything I have learned over the years, it is that you can never underestimate the resolve and capability of the great people and companies in this society and industry.  If the consumers want it, we can make it.  With flexible displays, we also expect to see entirely new design platforms, and who knows what new products will be created.

As a final thought, I again take you back to 1995 on a Tuesday evening at the Walt Disney Dolphin Hotel.  First year in graduate school and just entering the field, as I sat in the audience of a panel discussion titled, “Can FPDs Replace CRTs?,” I had no idea I was already on the amazing ride that was the first display form-factor revolution.  Twenty years later, I am quite prepared for the second.

Enjoy the ride.  •


Ruiqing (Ray) Ma is Director of Flexible PHOLED Lighting R&D at Universal Display Corp.  He can be reached at RMA@udcoled.com.