Touch screens set to get clearer

Posted by Emma Woollacott

Washington, DC — A test has been developed that should improve the performance of smudge- and glare-resistant touch-screens.

"Surfaces are particularly important in consumer products. This work investigates how products can be modified to reduce smudging and reflections. These modifications can offer improved resistance to fingerprints, anti-reflection properties or enhanced physical resistance," Steven Carlo told the American Chemical Society.

The basis of anti-smudge coatings is a compound called perfluoro alkyl ether, a derivative of Teflon with added ether groups to enhance its repellent effects. Anti-reflective materials use alternating layers of material, including silica and aluminum layers, to bend and diffuse light to reduce glare.

Since traditional chemical techniques could not be used on these super-thin coatings, Carlo and his team used depth profile X-ray photoelectron spectroscopy (XPS). The data allowed them to compare chain length, degree of branching and the hydrocarbon and fluoroether content of various samples.

The fluoroether content has a key effect in enhancing efficacy. Anti-reflective coatings need alternating layers, which have differences in their refractive index, a measure of how fast light travels through a material. Fluorocarbons in general have low RI and they offer anti-smudge properties. XPS allowed the scientists to visualize the multi-layer structure and the chemical species present in each layer.

In general, the greater the number of layers there are in a coating, the greater the anti-reflective properties. Carlo and his team also discovered that more silica and aluminum layers led to better glare reduction.