While the first day was more business-oriented, with several key players showcasing business opportunities that printed electronics represented for them, the second day focused on technical solutions, allowing AFELIM members to share their findings under the theme: Printed Sensors.
Presenting technical papers provider Arjowiggins, AFELIM member Gaël Depres praised the benefits of the company’s Powercoat paper solely developed for printing electronics, with a roughness below 10nm, not so far from that of PET. The company has also developed a platform it calls Powercoat Alive, whereby it combines printed sensors (temperature, pressure, breakage, humidity) with NFC tags to be read by smartphones. While the sensors and the NFC antenna are fully printed, they are co-integrated with a silicon NFC chip (roughly 0.1mm thick) using pick-and-place equipment.
To wirelessly connect the smart labels and packages it prints for its customers, Arjowiggins is also exploring the use of Bluetooth Low Energy chips to create BLE beacons on paper, again using silicon chips to be co-integrated with the printed sensors. Depres noted that connecting the printed circuits with the silicon parts placed on paper remains the main challenge, requiring pad bonding with a silver paste and subsequent annealing.
But several printed NFC platforms have already been proven in the lab, let alone the printed NFC tags commercialized by Norwegian startup Thin Film Electronics ASA. Hence, why not bypass the connectivity issues by using a fully printed NFC chip, we asked Depres. Wouldn’t that be the ultimate goal for Arjowiggins?
“Simply because it is not reliable enough”, Depres answered. “In the long run, of course, we would like to be able to print the whole NFC tag if it can be proven to be reliable, since the pick-and-place of silicon components is costly for us.”
Commenting on ThinFilm’s printed NFC solutions, Depres discarded them saying they didn’t work reliably. At this stage, one of the attendees in the public commented that he knew of a wine producer who once had trialled ThinFilm’s NFC tags and had given up with the idea within a month of trying it out. “ThinFilm’s marketing guys are simply doing an excellent job at promoting printed NFC”, they joked.
R&D Manager at CEA, Romain Coppard who was presenting next his work on co-integrated sensors on foils and large area sensing surfaces made his own comments about printed NFC and RFID.
“Although I have been actively designing and demonstrating printed RFID in the lab, it doesn’t work well and that’s why it’s not in use today”.
Ten years ago, Wallmart was betting on the roll-out of printed NFC tags on every itemised package, but it hasn’t happened in the end. Coppard noted that semiconductor inks have a certain cost, they are very sensitive to humidity, so they need a protective barrier too hence a printed solution may not necessarily be cheaper according to him, especially with a minimum of five printing steps required for a transistor.
“I still believe in printed transistors, but not for RFID” he concluded the debate, casting a doubt on ThinFilm’s printed NFC tags’ reliability, just at a time when the startup is focusing on producing billions of them for luxury brands.
Even if yield is poor (something ThinFilm would not comment on at LOPEC), maybe some level of customer feedback and interaction is better than none and can be disguised as a near 100% hit. ThinFilm can well bet on statistics for its marketing campaigns as any faulty or unreadable tag could simply be considered as unread by the end-customer and would not show up negatively.
See also: Printed memory pioneer to focus on NFC