Stretchable Displays, Summer Days
by Stephen P. Atwood
There was a long line at the booth, and I debated whether to wait in it on the first day of the exhibition. Something was being shown in the back room of the booth that was obviously interesting to people, but there was almost no hint of what it was from the front. A clever ruse that would either pique my interest or make me wish I had not invested the time. Well, I did invest the time and it was worth it. In that dark alcove in the Samsung booth at Display Week 2017 was a demonstration of a stretchable AMOLED display that was as honest as it could get.
The roughly 9-in. display was shown in such a way that you could clearly see both the front-of-screen operation and a continuous, substantial, 2-dimensional mechanical deformation from the center region – enough that I feared it might fail after a short number of cycles. But as far as I know it kept working for all three days of the exhibition. This is what
Display Week is all about! I tip my hat to Samsung for its bold demonstration and to everyone else who brought with them the good stuff!
Amid all the polished product demonstrations, you could find some other risky and early-stage demos of great concepts and technology. These developments may still have some work due them, but at least their stewards felt safe showing them off. Maybe this is why, as the exhibition has matured, we’ve seen such enthusiasm for the I-Zone, where edgy and early stage are the requirements. Everything you see there is based on sheer innovation, and far more human capital than cash is invested in keeping the project alive.
Flexible and conformable capability is what our current issue of ID is all about. Guest Editor Ruiqing (Ray) Ma has done a great job developing a trio of Frontline Technology articles for us that represent the latest thinking and state of the art for stretchable displays. I recommend you read his excellent guest editorial first to get his perspective on the lineup in this issue. Some of the work in these articles builds on folding-display capabilities already demonstrated, and yet most of us have not seen these foldable products in the marketplace today. We’re still in the very early dawn of truly flexible and foldable products. I think this has to do, at least in part, with making them suitably robust and able to
survive not only bending but true stress and strain as well. And so, this issue provides the next steps toward the goal of true folding, bending, and conforming display-based products.
Authors Yongtaek Hong and colleagues at Seoul National University start us off with their very thorough survey of the many ways that researchers are currently pursuing truly conformable substrates and display structures in their Frontline Technology article, “Stretchable Displays: From Concept Toward Reality.” Included in this story is a mention and picture (Fig. 2) of the Samsung demo I referred to. If you did not have a chance to see it at the show at least you can see it here.
In “Stretchable Oxide TFT for Wearable Electronics,” authors Xiuling Li and Jin Jang tell us about a very novel concept for making an active switching backplane by selectively ruggedizing small islands on an otherwise stretchable substrate called polydimethylsiloxane (PDMS). When oxide TFTs are attached to the small islands on the PDMS, they remain safe from stress/strain while the overall structure becomes highly conformable. I think this is a very promising method for further development.
Also busy in this area is a joint team at Kent State and Jiangnan University who together report on their work on thermally sensitive LCDs in “Developing Liquid-Crystal Functionalized Fabrics for Wearable Sensors.” This work entails creating liquid-crystal capsules that can be embedded into a wide variety of fibers and films to create temperature-sensitive, color-changing (“thermochromic”) materials that can be used for many purposes, including clothing, medical sensors, etc.
Our applications feature for this issue continues the core theme with a story about a new family of materials suitable for flexible-display substrates called polysulfide thermosetting polymers (PSTs). I say “new,” but in fact this work has been in progress for more than 10 years, first destined for biomedical applications but now found to be very advantageous for display applications as an alternative to polyimide. PSTs enable transparency, solvent-free fabrication, very low surface roughness, and low-temperature processing, all at reduced total material cost – so say the authors Tolis Voutsas, et. al. from Ares Materials, Inc., in their article, “New Polymer Materials Enable a Variety of Flexible Substrates.” I really like the possibilities discussed in this article and what they mean in terms of more options for the flexible-display materials infrastructure.
Our Market Insights focus this month is on a small but powerful company in our industry called Pixel Scientific, which until just recently was known as Tannas Electronic Displays, the founder of custom resizing technology for LCD glass. If you’ve ever seen uniquely sized LCD panels in cockpits of planes, in digital signs, or in industrial automation equipment, odds are they were custom sized from larger commercial panels using the Tannas patented technology developed by display visionary and pioneer Larry Tannas. In 2015 Dick McCartney (CEO) and fellow investors bought the company from Tannas, and now they are carrying on with its custom display-sizing technology and savvy portfolio management, while also branching out to new areas. Our own Jenny Donelan spoke with Dick about this endeavor and gained a wealth of insights about the company, its extensive patent portfolio, and the industry at large. Note especially Dick’s comments about investing in intellectual property protection and the benefits it can bring to your business. We’ve published a number of articles in the past about IP development and the patent process. This continues to be one of the most critical areas of concern for technology developers and a properly executed strategy will pay many
benefits for years to come.
We were all at Display Week just about a month ago (as of this writing) and while our expanded coverage is still in development, we figured we’d put in just a taste by publishing some of the best blogs that we developed and posted on-line during the event. And so, we offer a short compilation of some of the hot topics at the show, including foveal rendering, high-resolution automobile lamps, flat-panel speakers, very high-pixel-density phones, etc. from Display Week 2017 in Los Angeles. If you want to know more and were not there, stay tuned for our next issue with full coverage from all of our talented roving reporters.
Despite all the great things to work on inside the walls of your business, don’t forget that we’re in the middle of the summer and it’s a great time to reset your work-life balance as well. Take time to enjoy the outdoors, spend more time with your family, and visit someplace you’ve never seen before. Rekindle old friendships and make new ones. It’s shaping up to be a great summer, both inside and outside of our unique industry, and I wish you all good health and some much-deserved recreation as well. •