Microstructures capture the moth-eye effect

Microstructures capture the moth-eye effect

A new method to prevent reflections

Aarhus - Actura Nanotech / CDA now makes it possible to alter the reflective properties of surfaces.
Up until now, a multi-layer structure has been used for modification of reflexion characteristics. The
technology deployed by CDA allows the surface properties to be altered without applying additional
layers, making production cheaper and more flexible.

 

Undesirable reflections of light are caused by the varying refractive indices of glass
or other materials and of air. A solution to this problem is found in nature,
particularly in the optical properties of moth-eye surfaces. These consist of fine
nipple structures that alter the refractive behaviour of light not abruptly, but
gradually. The sharp boundaries between the different refractive indices are thus
eliminated, making the transition almost fluid and allowing the light to pass through
unimpeded. The sizes of structures required for this must be smaller than the
wavelength of light, i.e. a max. of 300 nm.

Examples of where the moth-eye effect can be deployed include anti-reflective
surfaces for mobile phone displays or displays in vehicles. Another positive effect
is that a higher light efficiency is achieved in case of such an antireflective surface.
Until now, refraction and reflection characteristics have been altered via a mostly
multilayer coating process. CDA, in contrast to this conventional modification,
enables a new and more cost-effective production. "We carry out submicrometric
patterning of polymer surfaces, which has the advantage that layers cannot flake
off," said Dr. Nicolaus Hettler, Managing Director of CDA. The new process thus
gives ample scope to possible new applications.