Displays and Touch Technology
Transparent Conducting Films
Transparent Conducting Films (TCF) are used in a wide variety of devices and applications:
- Touch Screens
- Conformal 3D Touch Sensors
- LCD/Flat Panel Display
- Thin Film Solar
- Electrostatic Dissipation
- Heaters and defrosters
These are complex electronic devices with supporting circuitry unique to each type of device. For example, in a LCD (“liquid crystal display”) the picture is created by manipulating the liquid crystals using an electric field that is created by passing a current through the transparent conductor. Without a TCF, the display business would cease to exist and touch screen applications would not be possible. Similarly, in a thin-film solar cell the top layer is also transparent. Without a TCF, thin-film solar photovoltaics could not be manufactured.
In these applications, the top protective layer typically is a high-quality glass or in flexible applications, a transparent plastic. Although Indium Tin Oxide (ITO) is the current TCF of choice today, it has notable deficiencies in mechanical integrity, yield, and cost. For these reasons, alternatives are being sought to minimize or eliminate use of ITO-based TCF. Despite its deficiencies, ITO is the dominant material in displays. However, inroads are being made by alternatives to ITO such as single walled carbon nanotubes (SWCNTs) and metal nanowires.
SWCNTs, or hybrids made with them, are likely the future of TCFs given their superior characteristics. SWCNTs have many characteristics that make them the ideal TCF:
- An individual SWCNT is 99% transparent.
- SWCNTs are more conductive than copper.
- SWCNTs can be made into an ink which can be applied at room temperature and pressure, versus vacuum-based sputtering that is used to deposit ITO.
- Coatings made from SWCNTs are more durable and flexible than ITO or silver, given their inherent strength; SWCNTs are “stronger than steel”.
- SWCNTs can be made from a renewable resource, whereas ITO is not.
- SWCNT provide thermal formability for emerging 3-D conformal touch sensors, which is not feasible with silver nanowires, PEDOT or ITO.
- SWCNT are stable against oxidation or degradation in high humidity and not subject to electro-migration (compared to silver).
Nano-C is uniquely able to address the fundamental needs in TCF:
- Its materials provide a 30% to 50% lower cost to the customer
- Nano-C’s TCF product line uniquely addresses the needs for Capacitive Touch (<50 OPS, 90% T, 1% haze) through to ESD (106 OPS, >98% T)
- Nano-C’s cost and scalability advantage is derived from its patented low-cost, combustion-based technology exclusively licensed from MIT.
- It has developed patented, and patent pending, water-based and solvent-based inks enable multiple coating methods.
- It has patented SWCNT/ITO hybrid materials that extend the life of sputtered ITO by over 2.5 times
- It has developed unique SWCNT-metal composite films that mitigate the weaknesses of each, by capitalizing on each of their strengths
- Its novel ink-based approach integrates easily with existing supply chains