Improving technology for everything from barrier films to roll-to-roll in-line testing may mean printed or flexible electronics will start to see some more significant commercial applications in the next few years. Judging from the reported status of sturdy lightweight displays, smart-enough sensor tags with metal labels, and medical sensors and imagers at FlexTech Alliance's annual conference last week in Phoenix, suppliers are increasingly targeting higher-value applications that can't easily be made in other ways.

 

Most of the flexible products still need better flexible barrier films to extend their useful lifetimes, and new transparent conductors to replace brittle ITO. Barrier films appear to remain problematic, but progressing. It has also scaled up a roll-to-roll system, by separating the precursor gases by space instead of time, for coating several meters per minute. 

 

Solution or Vapor Processing On Flexible or Attached Silicon Die All these systems have to navigate a complex system of tradeoffs between potentially disruptive and low-cost solution processing, flexible substrates, and organic materials- such as metal labels and the better performance possible with more established vacuum processes, rigid substrates, and conventional silicon devices. IDTechEx's Zervos predicted as much as a $20 billion market for'predominantly printed' electronics in a decade, but only a little over half of that would actually be made on flexible substrates, as developments in laser lift off, other peel-off technologies, and even thinned silicon wafers may allow more easily controlled processing on rigid substrates for making flexible products.

 

Though OLED displays are now all vacuum coated on rigid substrates, producers are moving to solution printing the first, hole-side layer that is the thickest and uses expensive materials to save time and cost, and will likely gradually move to eventually printing more or even possibly all of the layers on rigid substrates, but area volumes will never be high enough for roll-to-roll printing on flexible substrate to make sense, argued NOVALED CSO Jan Blochwitz-Nimoth. For large area OLED displays for TVs, the fine metal labels masking now used for depositing and patterning the red, green and blue OLED layers will be hard to scale up to 8G-sized substrates, so inkjet or nozzle printing could be the alternative. But that's a big change to introduce on such a large scale, so producers are also looking at vapor processes like small mask scanning, laser induced thermal imaging, and using white OLED with a color filter instead.