Printed dose-recording tag based on organic complementary circuits and ferroelectric nonvolatile memories.

We have demonstrated a printed electronic tag that monitors time-integrated sensor signals and writes to nonvolatile memories for later readout. The tag is additively fabricated on flexible plastic foil and comprises a thermistor divider, complementary organic circuits, and two nonvolatile memory cells. With a supply voltage below 30 V, the threshold temperatures can be tuned between 0 °C and 80 °C. The time-temperature dose measurement is calibrated for minute-scale integration. The two memory bits are sequentially written in a thermometer code to provide an accumulated dose record

Bending machine for testing reliability of flexible electronics

A novel bending machine has been designed and tested. It enables flexible electronics to be subjected to repeated bending with constant radius and tension. In-situ electrical characterization can give accurate analysis of lifetime distributions if sufficiently many samples are ran to failure, allowing reliability prediction models to be developed. Four sets of test samples with different combinations of substrate, routing, interconnect technology and components were examined. A poor level of reliability was observed when using anisotropic conductive paste to form interconnects, whereas a significantly higher level of reliability was observed when using a bismuth-tin solder paste. The assembly of larger components resulted in shortened time to failure, whereas increasing the bending radius prolonged the observed lifetimes.acceptedVersio

Smart Tags that are exactly Reliable Enough

Smart tags for fast moving consumer goods are among the products predicted to be part of the Internet of Everything. The tags must be extremely low cost, be fabricated in huge volumes, and have a quality accepted by the end user. Screening tests have been performed to evaluate technologies for hybrid integration of smart tags. An anisotropic conductive adhesive (ACP) was compared with use of a low temperature solder and critical factors limiting the quality of each technology were identified. The motivation for the research was to avoid over-engineering of the quality of the joints where this would correlate with too high costs. For the system with an ACP, the matrix material was identified as the critical factor whereas for the soldered system, the quality of the backplane appeared more critical than the soldered joints themselves. Draft specifications that were considered in this work were not met for the system with ACP whereas they were easily met for all tested soldered systemsacceptedVersio