In a recent product introduction, Cypress Semiconductor mentions a new approach to mobile touch sensor technology, called metal mesh. It said the company is partnering with FujiFilms to bring this technology to a wider range of smartphones as an alternative to traditional indium tin oxide (ITO) and aluminium-doped zinc oxide (AZO) displays.
I have been keeping an eye on the display market and I noticed recently a couple of trends recently that seem to me required something other that AZO and ITO based designs. One is the trend towards larger displays in traditional mobiles and tablets and the other was a shift to "up close and personal" wearable electronics. Both will need more flexible display substrates that are less prone to cracking in the case of large screen mobiles and are more flexible and bendable for wearable devices.
Talking to Vikas Dhurka, product marketing director for TrueTouch touchscreen solutions at Cypress, I found out that they had spotted the same trends and think that FujiFilm's metal mesh technology is a very promising way to address both issues in a potentially very large market.
According to Jennifer Colegrove, Ph.D., president of Touch Display Research Inc., the potential market for flexible and curved displays in which metal mesh would play is estimated to grow from less than 1% market share this year to $27 Billion and 16% market share of global display revenue by 2023 (figure).
Figure. Market for up close and personal flexible and curved displays. (Source: Touch Display Research, Flexible and Curved Display Technologies and Market Forecast Report, September 2013)
Durkas said metal mesh displays are built using thousands of copper wires, each smaller in diameter than a strand of human hair and offer greater flexibility. In traditional consumer electronics devices, he said, shifting from the traditional indium tin oxide (ITO) based screens to ones based on metal meshes made of copper would not only make them cheaper to produce but make them more noise immune and easier to manufacture.
"ITO is an etching process that is expensive, while metal meshes are laid down in a process similar to that of a semiconductor device in a layered fashion," said Dhurka.
Based on its assessment of the technology, Cypress Semiconductor has expanded its TrueTouch capacitive touchscreen controller family to include support for metal mesh sensors technology from Fujifilm as an alternative to indium tin oxide (ITO) and aluminium-doped zinc oxide (AZO).
Among the reasons for the shift, he said, is that because the metal mesh sensors are copper based they face less resistance in sending signals out to the electronics than existing multi-element based compound materials, making possible brighter and more easily readable displays.
But what made Cypress sit up and take notice is that unlike ITO or AZO, metal mesh sensors are bendable, which will be a requirement for many of the personal wearable electronic things that are considering for the next generation of consumer electronics.
"ITO is prone to cracking as standard smartphone and tablet screens get larger," said Dhurka, "and in the more curved flexible screen wearable designs that are being considered it is not a viable alternative."
But beyond the bendable features, an advantage of metal mesh is that it will allow mobile makers to build lower cost phones with capacitive touch technology. The technology also improves touchscreen sensitivity and delivers robust noise immunity.
Because the mesh consists of almost invisible copper wiring with the diameter of a hair, a display built using it is much more transparent than one built with ITO. Unlike ITO, a display fabricated with hair-thin (4 micron diameter) copper wiring can be very dense before transparency is affected, allowing the incorporation of additional electrical redundancy which improves yields and lowers cost.
According to Dr. Colegrove, metal mesh-based touch displays will make possible the creation of next generation of aesthetically pleasing wearable devices and things that because they are bendable can be contoured to the curves of human body. "Flexible and curved displays are more ergonomic for the wrist," she said, "and larger-sized flexible displays could fit better and show more information."
Cypress is offering the CY3290-TMA500 and CYTK58 TrueTouch Evaluation Kits for developers who want to design their next UI-based products with Fujifilm metal mesh sensors. But Cypress and FujiFilm are not alone in going after this new consumer and mobile display technology.
Metal mesh has started shipping in a couple of nextgen touchscreen-based smart phones. And competitors to FujiFilm such as MNTech in Korea and Unipexel are shipping metal mesh to their customers. Also, Atmel has partnered with CIT in the United Kingdom and as of late last year shipped its metal-mesh based XSense line of flexible touch sensors for use in a smartphone and a seven inch display Tablet. Several companies in China are also shipping.