Metal Mesh Touch Sensors

The TGM event presented several viewpoints on the prospects for non-ITO touch sensor films. During his tutorial on October 28, Geoff Walker of Intel provided his perspective on the need and potential alternative materials for a replacement for indium tin oxide films to be used as transparent conducting films (TCFs).

Walker cited his view that metal mesh has significant cost advantages, especially low operating cost combined with low costs for capital equipment. Geoff went on to deliver an overview of metal mesh, silver nanowire, carbon nanotube, graphene and conductive polymer TCF alternatives. He summarized his views on TCFs making several points: “It’s about the ITO in touchscreens, not in LCDs (ITO used in LCDs is 1-2% of cost (~$4 for a 40” display), LCD makers are extremely reluctant to make changes in fabs); it’s not really about flexible displays, at least not yet…; it’s not really about the indium supply or cost, it’s about the processes that ITO requires, not about ITO itself; mesh and silver nanowires are the main competitors and mesh seems to be taking a strong lead; this entire market has come alive exceptionally quickly!” Based on his comments I understand Walker to be pretty bullish concerning his expectations for the market success of metal mesh touch sensors.

Dan Van Ostrand of Circuitous Printing Advisors presented at TGM 2014 on The Challenges of Metal Mesh Touch Sensors and provided a solid in-depth discussion of the demanding manufacturing and display performance requirements faced by metal mesh touch sensor films. Van Ostrand identified the benefits of and trends for metal mesh versus ITO as: lower electrical resistance; lower cost of goods sold for larger sizes; demand for touch sensors continues to increase with continual pressure to reduce costs; current ITO manufacturing facilities at or near max capacity; and finally, capital costs for metal mesh manufacturing facility and equipment is lower than ITO. He discussed a variety of metal mesh types including nano- and micro- particle (Fujifilm, O-film, 3M, and others) as well as solid metal (Atmel, UniPixel, Toppan, DNP, Poly IC and others) and did not cover nanowire conductive film in his presentation.

In his presentation Van Ostrand went on to discuss in considerable detail the optical requirements and manufacturing yield issues for metal mesh touch sensor films. He considered all the optical and manufacturing issues relative to ITO films, and concluded that metal mesh can deliver optical performance nearly equal to all but the very best ITO films and that the need to meet the optical performance of ITO films is driving the production methods for metal mesh films to their limits. I concluded that the speaker believed that the industry will drive improvements in manufacturing methods that will ultimately deliver higher performance metal mesh touch sensor films that will take considerable market share from ITO. – Phil Wright