Feature Story

This Is What the Future of Touchscreens Looks Like

by Sri Peruvemba, Vice President, Cambrios Technologies Corp.

Flat and breakable are out. Flexible and durable are in. Every industry experiences it and its endemic in the tech sector. Dot matrix to laser printers, desktops to laptops and tablets in computers, discrete ICs to systems-on-a-chip.

In touchscreen technology, particularly in consumer devices, the rapid transition is on from touchscreens using the incumbent material, indium tin oxide (ITO) to electrodes based on silver nanowires (AgNW). This change in touch technologies, particularly where screen flexibility and other new properties are required, is because of several easily understood differences between the two transparent conductors.

The Flexibility Advantage

Firstly, silver nanowires are super-flexible and ITO isn't at all. That's highly significant by itself. Being able to make a touchscreen display flex opens many new design possibilities particularly for rugged, wearable devices. Current product design trends include flexibility. In real-world tests, silver nanowire coated films withstand greater than 100,000 turns around a 3mm bending radius, demonstrating a great fit in imaginative new electronic products.

The most popular touchscreen technology is projected capacitance, or "pro-cap." At the core of this technology is a transparent conductor - a layer of material that needs to conduct electricity while remaining transparent and allowing light from the underlying display to shine through the screen. ITO, the legacy conductor material, is neither very conductive nor transparent compared with AgNW.

But there are several other important differences that are also pushing the shift.

Because silver is the most conductive material in use, when creating large area touchscreens, like 20-inch monitors, higher conductivity is essential for a fast response time and to detect ten-finger touch. In laptops and smartphones, film-based transparent conductors can create thinner, lighter and more durable touchscreens. Higher transmission also enhances battery-life-per-charge and creates brighter displays since the silver-based touch sensor does not impede light as greatly as traditional materials.

Less to Manufacture

If more performance wasn't enough to drive the use of this new material, how about reduced cost? Single-layer touch sensors based on silver nanowires offer notably lower cost than ITO because they use fewer layers of adhesives and conductors in the touchscreen stack so there's less manufacturing complexity and materials used. Thin is in because nearly all products, particularly in the consumer electronics domain need to appear sleek and aesthetically attractive.

When costs between AgNW and ITO are compared directly, silver nanowire-based touchscreens range from slightly less to significantly lower than equivalent ITO film-based solutions. This is because of AgNW's room-temperature laser patterning process. Laser patterning equipment costs are also lower. For emerging touchscreen applications, including large-area touchscreens, as well as miniature, flexible displays, silver nanowires offer a significant performance and cost advantages. Further, the process requires no consumables and there are no waste disposal problems. It's also a greener way of making the required materials used in new touchscreens.

The material is already being used in several consumer products while offering lower manufacturing and per-unit costs and makes scaling far easier. Roll-to-roll processed silver nanowire transparent conductors are the clear choice for new production facilities that need high throughput and easy processing. They're also on target for OEMs needing a thin, light, flexible material delivering high performance for their next breakthrough products.

The Forecasted Shift

"Flexible electronic components will become a $27 billion market in 2020 which includes flexible displays, batteries, touch screens and sensors," said IDTechEx CEO Raghu Das. "This huge market is driven by the need for lighter, more robust and new form factors desired for industries such as wearable technology, automotive and healthcare. Flexible electronics can now conform electronics around our world away from the rigid bulky devices that will become yesteryear. OEMS are making billion dollar capital investments today."

Breakthroughs in transparent electrodes based on silver nanowires are simplifying electronics manufacturing processes and improving end-product performance for current and next-generation consumer devices incorporating touch technology. There isn't a downside. The material is cost-effectively accelerating the transition to flexible and wearable devices.

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