As part of Ink Week, the National Association of Printing Ink Manufacturers (NAPIM), along with Ink World and Printed Electronics Now, held the Virtual Fall Technical Conference from Oct. 12-14 and the third annual Electronic & Conductive Ink Conference on Oct. 15-16.

The Electronic and Conductive Ink Conference showcased the latest trends in conductive inks and flexible and printed electronics, with talks on smart packaging, displays, sensors, healthcare, equipment, testing, and, of course, conductive inks.

Estimates place the conductive ink field at more than $2.3 billion, and since flexible and printed electronics applications are becoming more commercial, the market is growing. New technologies are being developed to meet the needs of new sensors, wearables, displays, smart packages and much more.

Intelligent Packaging

Keynote speaker James Lee, director, Innovation Solutions Group, Jones Healthcare Group, opened the conference with his talk, “Our Journey to Produce Intelligent Packaging.”

Jones Healthcare is a packaging converter whose roots go back to 1882. The company has almost a century in different healthcare sectors.

“We produce products for pharmacies and pharmaceutical companies, natural health products, medical device, personal care and wellness and consumer goods and specialty products,” Lee said. “Our journey into smart packaging began about eight years ago when we asked how we could differentiate ourselves.”

Lee said that getting track and trace information for our customers, engaging consumers more dynamically, and improving healthcare outcomes with packaging were some of the goals. The next question was what features could be added and how would Jones manufacture them.

“Fifty percent of medications that are prescribed are not taken by patients,” Lee observed. “We wanted to make these products smart, and printed electronics can do that, and we joined the National Research Council of Canada consortium. We knew how to manufacture at extremely high speeds, but we knew the market had needs that aren’t being met.”

Jones Healthcare wanted to find a way to monitor blister packages, and advanced from a single cavity to 28 cavities. The next advancement came with a change in substrate.

“We had to get this to scale using silver and carbon inks on PET using flexo,” Lee noted. “Our market wanted to get away from plastics, so we needed to change to a paper substrate rather than PET.

“We printed conductive traces,” said Lee. “The conductivity of these traces is enough to provide sensing capabilities. To make it work, we had devices that could interrogate the packages. We could print 200 feet per minute with no cleanroom and unmodified printing equipment. We also did concurrent development in NFC inlays and can apply NFC verified tags greater than 5,000 units per hour in an integrated fashion. We are currently focused on printed electronics and NFC.”

Jones Healthcare recently introduced its CpaX Connected Packaging system, which connects the patient to the doctor.

“With CpaX, the cartons connect to the internet so doctors can know if the patient is taking their medication,” said Lee. “It generates reports, detects and tracks exactly when each dose is taken. Our Electronic Adherence Card (EAC) is a reusable monitoring and transmitting device, and we have developed a disposable card where the conductive ink circuits printed across each cavity act as ‘break sensors.’ We can produce 100,000 of these cards in an eight-hour shift.”

The Future of Food

Eric Weaver, CEO, Transparent Path spc, followed with a powerful talk on “Printed IoT and the Future of Food,” offering sobering looks at food wastage and how printed electronics can help in that regard.

“Forty percent of our food, $218 billion worth, is lost every single year,” Weaver said. “It goes straight from the farm to the landfill. Yet 17 million US children are going hungry every day. This is a huge problem.

“We are shipping food anywhere and everywhere these days. We get 80% of our seafood, 50% of fruit and 40% of vegetables from outside the US, and 75% of all food loss occurs in the supply chain before retail, according to Maersk,” Weaver reported.

Drivers haul perishable food across the country and sometimes turn the refrigeration off. If this occurs in Tucson, temperatures can go to really dangerous levels, and then people starting to get sick. Food companies share stories about how they employ people to try to find out what happened, but missing information makes it difficult if not impossible.

“Today, food producers throw sensors into their food shipments,” Weaver added. “These sensors are completely reliant on drivers and retailers. Truckers worry about being tracked and would just toss them out of the truck.”

Weaver said the first step is to fill in the black hole of data; a single import shipment requires 30 to 100 paper documents on average.

“Rather than download USB data or manually input data, we use IoT sensors that are continuously connected and provide a ledger with temperature, humidity, light, air pressure, shock and tilt,” Weaver added. “We can share this data across partners, and an AI engine operationalizes that data. We apply sensors to the food shipment load, and if we have a growing problem, we can alert the driver in real-time to fix the issue, and we can show the driver did exactly what they needed to do. All of the partners are aware of what is happening. It gets rid of ‘he said she said.’”

“By bringing printed sensors to food, printed electronics will help guide the future of food. Printed electronic and conductive inks can make a huge difference in our food’s future,” Weaver said. “The technology keeps moving forward, and I really do think this is a two-year target.

“As printed electronics sensors mature, package level monitoring becomes more economically feasible, and it can be monitored at an individual package level. Our dream tag is a 1.25” printed temperature and humidity sensor with minimum three-month battery life at 10-minute reads, using a biodegradable ink and a water-soluble substrate. It would have a printed battery or ambient power.”

The Future of Conductive Inks

Conductive inks were the subject for the next three talks.

Chris Booher, chief marketing officer, ChemCubed, discussed “Advantages of Particle-Free Silver Conductive Inks in Thin-Film Printed Electronics.” Booher noted that the explosion in the number of IoT devices is leading to increased interest in printed electronics.

“Thin-film flexible electronics place conductive traces on a conformable, stretchable substrate that are nanometers to microns thick,” he continued. “It is making new devices possible that were never possible before.”

Booher pointed out that ChemCubed’s ElectroJet ink technology requires less time and temperatures for sintering.

“It’s more about the ink than you think, including conductivity performance, sintering temperature and time, compatibility, physical durability and flexibility,” Booher added. “Dielectric inks have compatibility and encapsulation considerations and adhesion capability to substrates. Nano-particle silver inks are opaque in color with particle loading of silver from 15% to 40%, and the rest is filler and resins that will settle out. ElectroJet is particle-free silver ink and transparent. It is void-free and fully conductive and has excellent adhesion of multiple substrates. Particle-free dry film layers are essentially near bulk silver.”

Brian Violette, applications engineer II, Creative Materials, followed with “Direct to Fabric Printing of Electronic Materials.”

Violette began by noting that many devices have been printed since the popularization of membrane touch panels in the early 1980s, and screenprinting has been around for more than a thousand years. New form factors are now using stretchable substrates.

“Heaters have been printed in jackets and pants – they are a quite common application,” said Violette. “Printed electroluminescent panels for workwear and safety, sensors for medical applications like arch supports – there is no shortage of devices that use printed electronics.”

“There is a huge range of options onto textiles,” Violette added. “Although many substrate choices are available, there has been very little work for them using printed electronics. Most functional inks are not designed to elongate.

“Most applications benefit from having conductive layers applied twice,” he noted. “The first layer uses high squeegee pressure pushing ink into the textile. The second uses low squeegee pressure, creating additional ink coverage for improved performance. The most common failure is cracking of the conductive ink trace.”

Sai Srinivas Desabathina, manufacturing engineer, Liquid Wire, Inc., closed the first day with his talk on “Electromechanical Characterization of Flexible Inductive Proximity Touch Sensor, Fabricated Using Liquid Wire's Metal Gel.”

Desabathina noted that Liquid Wire was founded in 2016, and has patented its Metal Gel fluid phase conductor. The company has partnered with Panasonic partnership enabling flexible printed circuit solutions.

“Metal Gel is a proprietary alloy of gallium, indium and tin,” said Desabathina. “We can directly print high viscosity fluid that flows and stretches with substrates. It is substrate agnostic. It is ideal for wearable applications such as EMGs, breathing monitors and pres-sure sensing. Our inductive sensors are deformable and flexible. It should be commercial by 2021.”

Smart Objects

The Friday, Oct. 16 session began with Dr. Christian Brox-Nilsen, R2R production manager, Ynvisible, who gave the keynote talk, “What It Takes to Make Smart Objects Smile.”

Ynvisible offers lab scale, pilot production and full volume roll to roll production. Its ink development is done in Freiburg, Germany.

“Inks are at the core of our daily operations, from electrolytes to electrochromics,” Dr. Brox-Nilsen said. “Some inks we buy commercially and some we have developed in-house.”

Ynvisible can produce on sheets or rolls, which allow for large volume production.

“Printing on sheets is typically where we start when we are testing and can be scaled up to roll-to-roll. We make test trials on sheets,” Dr. Brox-Nilsen said. “The process we most often use in screen, but we also use slot die and gravure. For displays we use screenprint-ing. We also contract manufacture, such as moisture sensors and energy harvesting.”

Silver Nanowires vs.ITO

Thomas Kolbusch, VP, Coatema Coating Machinery GmbH, followed with his excellent talk on "Silver Nano Wire Upscale from lab2fab - Overview on the Development on R2R Pro-cesses."

“We make coating, printing and laminating equipment. Our vision is lab2fab,” Kolbusch began. “We build lab systems from lab to pilot and production systems. Flexible, thin, robust, lightweight and stretchable. Nowadays, we speak more about integrated hybrid systems combinations of printing and silicon systems.”

Kolbusch noted that Coatema sees the need for replacing ITO in different markets, including flexible displays for smart homes, cars and smartphones.

“IDTechEx says a replacement will grow significantly as ITO is not flexible,” Kolbusch noted. “Silver nanowires are highly conductive and offer a larger surface area and aspect ratio. We started flexible displays out of polymer materials, then people are moving to stretchable applications for medical. Now we are seeing bendable displays. You don’t want to lose conductivity.”

As for alternatives for ITO, Kolbusch believes that silver nanowires and metal mesh are the two leaders.

“There are a lot of different approaches, such as metal mesh and silver nanowire, and there will be a competition between them,” said Kolbusch. “I don’t see carbon nanotubes and graphene as the answer at the moment. Maybe in 10 years. The biggest application for silver nanowires is large touch screens.”

New Applications

Dr. Matthew Dyson, technology analyst, IDTechEx, provided an overview of the conductive ink market in his talk, "Emerging Application Opportunities for Conductive Inks.”

“We estimate conductive ink being a $2.3 billion market,” Dr. Dyson said. “Flake-based silver inks are a mature technology, with screenprinting being the dominant approach. Nanoparticle-based inks have improved conductivity. More recently, we are seeing particle-free inks formed by in-situ reduction. Copper inks are a cheaper cost alternative over silver-based but it oxidizes easily. Liquid alloy metal gel inks have excellent functionality.”

In terms of applications, Dr. Dyson sees good opportunities ahead for in-mold electronics.

“We predict that in-mold electronics and RFID will become increasingly important,” he added. “In-mold electronics is drawing a lot of attention. Conductive traces are printed on a flat sheet, which is then thermoformed into a capacitive touch surface. You don’t have to wire everything together. The main challenge is the yield. Car manufacturers are interested in it.”

PCB prototyping, additive manufacturing, wearable electronics, e-textiles and flexible hybrid electronics are also good opportunities.

“There is a huge array of applications for conductive inks. I think the future for conductive inks is pretty bright,” Dr. Dyson concluded.

Testing Flexible Electronics

Eisuke Tsuyuzaki, GM, Bayflex Optics, discussed testing with his talk on “Better Testing Designs for Printed and Flexible Electronics.”

Tsuyuzaki noted that flexible electronics need to move with the human body – stretch-ing, flexing and twisting – but people are dealing with semi or rigid assemblies, small components and very fine cables and wiring.

“Because it is flexible, it is extremely important to test raw materials in the front end of the process rather than the end,” added Tsuyuzaki. “Flexible components and products require repeatable real-world mechanical tests, and the use of counterweights leads to imperfect mechanical test results.”

Bayflex has developed modular desktop endurance systems since 2009, and these systems do a range of testing, from stretching and twisting to folding and more.

“There is a transition from semi-rigid to flexible components,” Tsuyuzaki observed. “Companies also want to be able to read data in real-time. We are moving this into a cloud-based program in 2021.”

Sticker Electronics

OmniPly CEO Harit Doshi closed the conference with “Sticker Electronics.”

Doshi began by noting that CTR display technology dates back to 1925, LED to 1964 and OLED to 1987. Today, OLED displays account for 37% of the display market, mostly smartphones. OLED shipments will be 4 million in 2020, growing to 11 million by 2021.

“However, OLED TVs are more difficult,” Doshi continued, noting that 96% of TVs are under $1,000.

OLED TVs have to become more cost-efficient,” he added. 

“Customers want larger displays and the way to do that is foldable displays,” added Doshi. “We believe this will be a driving factor for the flexible display market. The future bends and folds – it’s only a matter of time before the larger players will have a bendable or foldable form. I think a few years from now, we will ask how we managed with a 3.5-inch display.

OmniPly is working on sticker electronics, where the display is peeled off of glass and placed on another surface.

“We seem to be at an early stage of what is possible,” said Doshi. “Sticker electronics can be built and conformed to different shapes. OmniPly’s vision is a world where any electronic device can be pasted anywhere just like stickers, to add smart functionality to everyday objects. These could be used for fingerprint sensors, plasmonic films, medical sensors, flexible OLED, flexible solar cells and thin-film sensors. Our OmniPeel technology is fundamentally easier to use and will enable the future of flexible and sticker electronics.”