Antifog Coatings - Nowadays and Future use for Automotive Lighting Systems 2005-01-0616

The benefits of avoiding of fogging in today's mainly transparent headlamp lenses are enhancing the spectrum for headlamp designs, and are enabling stable light efficiencies, hence, conformity with safety aspects even under difficult ambient conditions. Headlamp systems which suffer from fogging do not provide the requested light intensity for a certain time as independent measurements have clearly shown. In parallel oncoming traffic will be glared. This effect is normally limited to some minutes depending on several parameters but it is undoubtfully not in accordance with the state of the art in view to achievable safety standards. To avoid fogging, innovative combinations of sol-gel chemistry and nanotechnology are now available for spray applications. Coatings on glass are state-of-the-art. Currently GXC introduces adapted and advanced systems for the use on polycarbonate substrates. The anti-fog treatment comprises a coating which has a spontaneous water-spreading effect based on an hydrophilic inorganic-organic matrix consisting of a nanoparticle-network supported by diffusible hydrophilic additives. The coatings on glass provide contact angles opposite to water of below 10°, an excellent long-term stability, high transparency, good adhesion, and a functionality accomplished by very thin coatings (below 3 μm). These properties are connected with low costs and easy processing. Considering that automotive lighting has subjected major changes during the last decade the general use of antifog coatings could be a gainful added value in that tradition.