This Small Business Innovation Research (SBIR) Phase I project will develop the technology necessary to pattern transparent conductive films previously developed by our group, allowing them to be integrated into functional consumer devices, such as capacitive and resistive touch sensors for flexible displays. Our team currently makes transparent conductive films based on silver nanowire technology. Silver nanowire meshes represent one of the most promising technologies to replace tin-doped indium oxide (ITO) in consumer devices. Films utilizing silver nanowires offer several advantages over ITO including lower cost, flexibility, and durability. For these bulk films to be useful in most applications, they need to be patterned into electrical circuits. This project focuses on the feasibility of direct laser patterning of these transparent conductive films for lab scale touch sensor development, as well as developing lithographic methods that will be compatible with processing techniques used in the electronics industry. Once these processes have been developed, we will create prototype touch sensors using these conductive films, demonstrating their use in one of many commercial applications to which this technology can be applied.
The broader/commercial impact of this project lies in both the development of the patterning technology itself, as well as the ability to turn our existing conductive film into a working electronic component. By enabling the integration of raw material into a working component, this research will allow for the integration in an actual touch screen device. Such demonstrations will allow the company to gain inroads with manufacturers of electronics that make use of touch sensor technology, permitting these manufacturers to begin integration of our transparent conductor technology into their products. Beyond these impacts, the research on lithographic patterning of nanowire films will push the patterning technology further, transitioning from a low-throughput, time-intensive method (direct laser patterning) to a high-throughput, accepted industry standard (lithography). Because most electronics manufacturers already process ITO lithographically, developing this technique will enable our materials to be a direct replacement for ITO in current manufacturing lines, eliminating the need for costly retooling.
– Sinovia Technologies Transparent touch panels are becoming increasingly prevalent in consumer technology. They currently exist in small devices such as phones, tablet computers, automobile dash panels, point of sale transaction pads, and ATMs. As the ability to interact with machines improves, the industry is naturally gravitating toward larger touch sensors, integrating them into large desktop computers and television screens. Large touch panels come with challenges of their own, both from price and performance standpoints, as increased areas mean increased materials usage, putting pressure on the suppliers of raw materials used to make these panels. Touch sensing panels are transparent devices that are installed on top of displays that allow light to pass through while maintaining the electrical functionality required to sense touch. They utilize transparent conductive materials to accomplish this. Tin doped indium oxide (ITO) is the industry standard transparent conductive material, used in practically all touch panels manufactured today. However, because indium is scarce and produced mostly in China, ITO is expensive and its price is volatile. It is also brittle, and its performance on plastic is insufficient for large area touch panels. For these reasons, the touch panel market has been looking for alternatives to ITO. Silver nanowire based transparent conductors are the front runner in the race to replace ITO. At this time, they are the only alternative that can provide optical and electrical performance superior to ITO at prices competitive with the ITO market. Sinovia Technologies is a Bay Area startup company commercializing silver nanowire transparent conductor technology. While several silver-based transparent conductor companies exist, our unique technology allows us to make conductive films with smoother surfaces and enhanced electrical performance. This SBIR Phase I study allowed us to develop the technology to pattern our conductive films, a necessity to turn our blanket conductive films into functional electrical circuits. We developed a laser patterning system for prototyping work at the lab scale as well as a lithographic process for patterning our conductive films quickly at the manufacturing scale. Our lithographic process also has the advantage that it can be run on commonly available equipment, so our customers can easily pattern Sinovia films in-house. After developing the patterning technology, we put it to use, creating prototype capacitive and resistive touch sensors using Sinovia conductive films. We successfully integrated the capacitive touch panel into a laptop computer, resulting in a functional demonstration of our films’ applicability to the expanding touch panel market.
