Flexible sensors: an expanding market

Guillaume Chansin, IDTechEx



Guillaume Chansin, IDTechEx

Large investments have been made to enable flexible, thin sensors rather than rigid sensors. $75 million was recently awarded by the US Department of Defense to establish a new Manufacturing Innovation Institute (MII) for flexible hybrid electronics in San Jose, California. Under the acronym FHE MII, this new entity will follow a hub and node approach managed by the FlexTech Alliance.

Meanwhile in France, a startup company called Isorg is building a new production line to print flexible sensors. Construction of the 3,000 square meter facility started last June and will cost a total of €20 million ($22 million). Once completed, the production line will be the first of its kind to manufacture optical sensors on plastic.

Printable electronics

Isorg has developed the technology to make organic photodetectors (OPD). Unlike conventional silicon-based photodetectors, they use organic semiconductors to absorb light and generate an electrical current. While organic light-emitting diodes (OLED) have already become mainstream on our smartphone displays, the OPD is relatively unknown.

What makes an OPD so unique is the fact it can be printed directly over large areas. What's more, the materials are inherently flexible, enabling much more design freedom in terms of size and form factor.

In the US, the newly established FHE MII has the potential to generate a lot of innovation in this field. The FHE MII will bring together 96 companies, 11 laboratories and non-profits, 43 universities, and 15 state and regional organizations. One of the consortium members, Brewer Science has already extensive experience in nanomaterials formulated for sensors.

Not just wearable

Another important aspect of the FHE MII is its emphasis on hybrid systems. In this context, "hybrid" indicates that some of the functions will still rely on conventional components. This is a wise approach, as it will speed up product design and commercialization. In the early days of printed and flexible electronics, many in the industry tried to avoid the use of any silicon integrated circuit (IC). But this "everything printed" approach limited performances and, by extension, the range of applications. The truth is that when it comes to signal processing, it is hard to beat silicon. Under the hybrid approach, silicon ICs will be thinned down, repackaged and integrated on the flexible substrate.

Thinning down the ICs is a delicate process but essential to make them more flexible and less obtrusive. This is an area that MC10, another member of the consortium, knows very well. This company made headlines two years ago when it launched a wearable head injury sensor with Reebok. More recently, MC10 has been promoting the concept of a BioStamp, a sensing device worn as a skin patch.

Flexible sensors can be useful in many other ways. In an interview for Bloomberg, Malcolm Thompson, Executive Director of the FHE MII, gave the example of an aircraft wing covered with thin, flexible sensors that monitor the integrity of the wing (Boeing is another participating company in the consortium).