Over the last few years, we have seen explosive growth of touch screen displays in the consumer electronics market. According to BBC research, the rising demand for transparent conductive coatings in smart devices, coupled with the increase in consumption of smart devices, has bolstered the global market for transparent conductive coatings.
For many years, ITO (Indium Tin Oxide) has been the standard solution for transparent electrodes, but it has a considerable cost, limited supply, and additional problems: high reflectance which reduces the contrast ratio and optical properties that degrade rapidly below a sheet resistance of 50 Ω/☐. These challenges limit the size of a display that can be produced using ITO.
Some ITO-alternative technologies, like carbon nanotubes, nanobuds, graphene, and conductive polymers cannot provide sufficient low sheet resistance or are too expensive to be considered for high-volume production. Furthermore, silver nanowires and nanoparticles have inherent problems with haze and transmission for materials with sheet resistance below <30 Ω/☐.
The only viable alternative to ITO (and the only solution for large touchscreen displays) is NanoWeb® (a metal mesh). Metal mesh has the capability to provide very high conductivity, approaching pure metal values, and at the same time keeping optical transmission high; comparable with uncoated glass or polymer substrates. High transmission is an essential requirement for modern touch display devices. Also, since metal mesh is fabricated by printing/patterning, this process can be integrated with trace patterning, which currently is responsible for more than 50% of touch screen production cost. The challenges that have kept this technology from immediate and widespread commercialization is the visibility of mesh pattern and the Moiré effect caused by interference of mesh pattern with the display’s microstructure. These challenges are the result of the coarse resolution of the mesh metal printing in current production: regular mesh is printed with resolution (conductor width) above 5 μm, which is clearly visible by the naked eye and contributes to the creation of Moiré fringes.
NanoWeb’s metal mesh has sub-micron lines lithographically fabricated with a desired two-dimensional pattern. NanoWeb® is completely invisible to the human eye, highly transparent and highly conductive (with a sheet resistance <5 Ohm/☐). This performance places the technology above all major competition providing an alternative to ITO. NanoWeb’s technical testing has resulted in excellent performance on glass and PET substrates, with aluminumand silver metals.
Benefits of NanoWeb™ for touch screen panels
- Enables submicron printing, resulting in 300-500 nm regular 2D metal mesh lines, invisible to human eye
- Sub-micron line metal mesh does not form Moiré fringes with display structures
- The only known technology to produce metal mesh electrodes with R<5 Ω/☐, T>95% and low Haze
- Allows formation of metal mesh on large rigid and flexible substrates
- Haze and transparency are not compromised with sheet resistances <30 Ω/☐
- The transparent metal grid and traces can be produced in the same process step/layer
- The only known technology capable of producing sub-micron metal mesh on glass or film on industrial scale
Learn more about NanoWeb and download your free guide!
