Rolith, Inc., a developer of advanced nanostructured devices, yesterday announced the successful demonstration of Transparent Metal Grid Electrode technology based on its disruptive nanolithography method (Rolling Mask Lithography – RMLTM).

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We see an explosive growth of touch screen displays in consumer electronics market. ITO (Indium Titanium Oxide) material is a standard solution for transparent electrodes so far. Apart from a considerable cost and limited supply of this material, it has additional problems: high reflectance of this materials reduces contrast ratio, optical properties degrade rapidly below 50 Ω/☐, which limits the size of display produced using ITO without degradation of performance.

The only viable alternative to ITO (and the only solution for large touchscreen displays) is a metal wire grid. The requirement for a metal wire grid to be invisible to human eye means that width of the wire should be < 2 micron. Moreover, narrow wires are helpful to fight Moiré effects, which caused by superposition of the metal wire grid and the pixel structure of a display.

Rolith, Inc. has used its proprietary nanolithography technology called Rolling Mask Lithography (RMLTM) for fabrication of transparent metal wire grid electrodes on large areas of substrate materials. RML is based on near-field continuous optical lithography, which is implemented using cylindrical phase masks.

Transparent metal electrodes on glass substrates were fabricated in the form of submicron width nanowires, lithographically placed in a regular 2-dimentional grid pattern with a period of tens of microns, and thickness of a few hundreds of nanometers. Such metal structure is evaluated as completely invisible to the human eye, highly transparent (>94 percent transmission) with a very low haze (~two percent), and low resistivity (<14 Ohm/☐). This set of parameters places Rolith technology above all major competition for ITO-alternative technologies.

Gen-2 RML tool capable of patterning substrates up to 1 m long and built earlier this year has been used to demonstrate this technology.

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“Rolith has launched Transparent Metal Grid Electrodes application development just few months ago, and we are very excited with the extraordinary results already achieved. We believe RMLTM technology will enable high quality cost effective touch screen sensors for mobile devices and large format displays, monitors and TVs. Currently Rolith is negotiating partnerships with a few touch screen display manufacturers and hope to move fast with commercialization of our technology next year. Our roadmap also calls for expansion into OLED lighting and flexible substrates in 2014-2015,” said Dr Boris Kobrin, founder and CEO, Rolith.