Dr Guillaume Chansin, Technology Anaylst at IDTechEx comments that printing sensing devices is not in itself a novelty. For instance, many vaccines shipped across the world now have a printed temperature label which alerts medical staff if the cold chain has been broken during transport and storage. However, these labels are not electronic devices: the ink undergoes a chemical reaction and changes colour when the temperature is too high.
Electronic sensors are usually more complex and manufacturing can therefore be more challenging. There are multiple layers of materials and the devices require metal interconnects. The manufacturing technique is selected based on the material properties, cost, and the resolution. For many years, printing (and in particular screen-printing) has been used to make sensors based on specialised ceramic materials. The problem is that these sensors require a sintering process which makes them incompatible with plastic components.
In contrast, the new sensors are based on inks that can be printed directly on plastic substrates. They offer advantages such as flexibility, thinness, light weight and, in some cases, the potential to be manufactured with roll-to-roll equipment. What it means is that these sensors will be usable on curved surfaces, in ultra-thin devices or for shock-resistant devices.
While there are many flexible sensors still in early R&D phase, IDTechEx says it has identified the technologies that are emerging and now near commercialisation. Those are:
• Printed gas sensors on plastic
• Printed temperature sensors
• Flexible photodetectors
• Flexible piezoelectric sensors
• Flexible digital X-ray sensors
2014 will be the year when some of these sensors will start shipping to end users. IDTechEx predicts a steady growth (see chart above) so that by 2020, the combined market value of the sensor modules will be worth almost $120 million.
"Printed and Flexible Sensors 2014-2024: Technologies, Players, Forecasts"; www.IDTechEx.com/sensors