The 2014FLEX Printed and Flexible Electronics Conference was held Feb. 3-6 at the Phoenix (AZ) Conference Ctr. As seen by the conference’s slogan, “At The Tipping Point,” the members of the FlexTech Alliance feel that the use of flexible electronics is finally emerging from its lengthy incubation period in governmental and industrial laboratories to make its commercial debut into the real world of consumer products. This year, there were 60 tabletop exhibitors at the show and more than 600 professionals in attendance.
The two main reasons for the optimism: 1) The rapidly growing interest in “wearable” electronics; and 2) The Oct. 2013 official introduction of flexible OLEDs by both Samsung and LG. Many of the papers presented at the show were either on the different approaches being developed to facilitate the manufacturing of flexible OLEDs or the driving forces propelling wearable electronics to the forefront. FlexTech has come a long way from its start as the “US Display Consortium” (USDC) that was focused on developing and maintaining an infrastructure for flat-panel displays in the USA to an international conference covering a wide variety of methods and materials now being used to manufacture printed, flexible electronics. One of the few similarities tying these two concepts together is the idea that roll-to-roll (R2R) manufacturing is the way to meet the harsh cost realities of consumer electronics.
Flexible OLEDs leading the way
It now appears as if flexible OLEDs will be the major force in driving flexible, printed electronics to the commercial forefront. While still forecasted to be small in 2014, the global market was predicted at the show by IHS to exceed $20 billion in 2020 and $50 billion by 2023.
The basic technology required for making flexible OLED has been available for a few years. However, these display materials have a very high sensitivity to water vapor and oxygen gas. Coming up with a cost-effective, flexible, transparent, ultra-high barrier able keep out both oxygen and water vapor (to a level about equivalent to one drop/month of water hitting the area of a soccer pitch) has proven to be quite a feat. Finding reasonably accurate methods to measure such a small amount of water vapor and oxygen gas has been almost equally difficult. Papers announcing breakthroughs in developing both acceptable barriers and instruments with these properties were presented in several sessions. It is still not clear whether the single layer design, the multilayer inorganic/organic-dyad construction or an as yet-unreported barrier construction will win out.
Significant progress in the equally difficult task of making flexible, transistor-based display drivers, adequate interconnects, front and back plane materials and flexible, transparent conductors also was presented in depth in the conference. One clear message was that transparent, organic semiconductors are here to stay. An example of this was a flexible, plastic image sensor developed jointly by Plastic Logic and ISORG that used all organic, thin-film transistors by Plastic Logic and printed, organic photo detectors by ISORG. The sensor has a 4x4-cm active area with 8,930 pixels. This device won the 2014 FLEXI Award. Flexible detectors are estimated to be a $1 billion market by 2020.
“Dick Tracy” watches for everyone
“Wearable” electronics also received plenty of attention at this year’s show, just as they did at the 2014 CES held earlier in Las Vegas. Flexible watches are a big part of this focus, ever since Samsung came out with its version late last year. It’s quite clear that their flat, “squarish” design is only a start for this fashion trend. Coming up with flexible (at least in one dimension) or moldable devices was another focus of the conference. This trend has already begun with the latest smartphones debuting this year.
There were also papers covering the adaptation of flexible sensors for use not only in monitoring and reporting medical issues, but also for providing feedback for self-monitoring one’s physical activities. Again, the form factor of being bendable or moldable to the person’s body, for not only more accurate measurements but also for comfort, was mentioned more than once. Another concern was how to make these devices rugged enough to survive “everyday” use but also the harsh human-body environment. Finally, the fact that many of these devices may turn out to be simply fads can have investors thinking twice. Selling into fads is a hard way to develop a long-lasting technology.
One aspect carefully avoided throughout the conference was the actual cost of these devices with their enabling technologies and materials. Historically, costs for technical breakthroughs and advances have come down quickly with higher volume and increased yields, but none of the speakers I heard were willing to discuss current costs or near-term trends. The constant downward price pressure for all commercially available products, especially those in electronics, is well known. Fads in both fashion and consumer electronics can support higher prices for only so long. It will be interesting to see how printed electronics will handle this parameter in the future.
Vacuum-coating, flexible glass, nanomaterials
There were a few papers pertinent to the converting industry. These include:
· Cindy Giroux of Corning spoke on the current status of flexible glass. She announced that the CAMM group has succeeded in making touch panels by R2R techniques from Corning’s flexible “Willow Glass.” She then made a plea for equipment manufacturers to address the need for designs to handle flexible glass in full production at speeds in the meter/sec range. Corning is now selling slit rolls of Willow Glass for prototype development.
· Rich Bake of SGIA discussed the use of inkjet for printed electronics. He said that inkjets were useful in doing short-run jobs and prototyping new applications, but in their current state they are not yet ready for high-volume production runs. With the issues of customized inkjet heads, the need for customized inks and ink prices, currently this printing technique to expensive for large runs.
· Neal Morrison of Applied Materials gave two talks. The first one was about vapor-barrier requirements for flexible OLED displays. He discussed their experiments and progress in depositing SiNx layers and about the impact of the surface smoothness and debris levels on the film’s surface. He also compared the lamination of a multilayer barrier deposited onto a carrier film vs. the direct deposition of a multilayer inorganic layer on top of an organic smoothing layer. The vacuum deposition of the SiNx was done by CVD.
· Morrison’s second paper covered the design considerations required for a R2R vacuum coater to deposit optimized and cost-effective ITO layers on polymer films for today’s PCAP-based touch panels. He showed actual performance levels for a four-layer, ITO-based stack with Rs of 100 ohms/sq with a %T level of 90% on a hard-coated PET film. This talk included a graph clearly showing what Rs level touch panels of different diagonals would need, and explaining why.
· One session was dedicated to non-ITO transparent conductive (TC) coatings. Talks were given by Carestream Advanced Material’s (FleXX) and Cambrios’ (ClearOhm) about their respective Ag NW-based coatings. Cima NanoTech discussed its “self assembly,” silver nanoparticles (Sante), mentioning that production coating of this film would be done in the USA this year. It became obvious when Kimoto Tech spoke about its introduction of two approaches for making non-ITO TC coatings, which were based on a conductive polymer (PEDOT:PSS) and “self assembly,” Ag nanoparticles, that Kimoto Tech was the US partner of Cima. Henkel discussed how transparent heaters could be made from their Ag-loaded, epoxy-based inks, pointing out that its approach would not make a TC film transparent enough to be used in touch panels.
· Multiple papers summarized advances being made to manufacture flexible, transparent, ultra-high vapor-barrier layers as well as production friendly ways of measuring the transmission rates of these barrier layers. Lorenza Moro of Samsung Cheil Industries gave an excellent summary talk on the barrier requirements and challenges still left to overcome. This is obviously not a straightforward job to do cost-effectively because, despite all the work done on ultra-high barrier coatings since the late 1980s, it is still the number one challenge for the high-volume production of flexible OLEDs.
In summary, this year’s 2014FLEX conference was an improvement over 2013. The number of talks given that addressed different problems and solutions outnumbered the purely commercial presentations of the past. This was the case, at least, in the sessions I attended. The organization of the conference was also much improved with only a couple of session chairs not sticking to the schedule, and any cancellation of papers was held to a minimum.
On a side note: “Packaging-centric” converters must be aware of the trends in smart packaging that are developing momentum now. Those that stay current with the technical requirements needed to participate in the smart-packaging market will be the successful ones. As the FlexTech motto this year indicates, “the tipping point” seems to have arrived.
The 2015FLEX will be held Feb. 23-26 at the Monterey Bay Conference Ctr., located near Silicon Valley in California. Hopefully all the program developments made in the right direction this year will be transferred intact to next year’s location.
Dr. John B. Fenn, Jr., can be reached at 818-888-8649, email: email@example.com