Bomb disposal experts see clearly now the mist has gone

摘要

A technology used to demist LCD displays has been successfully used for a ballistic visor in part of a project to create a complete advanced bomb disposal suit for the Ministry of Defence (MoD) With threats to security continually changing, so too must the protective equipment available to security services. One example is the lightweight face shields used by riot police and bomb disposal experts which, while having excellent optical characteristics, suffer from the problem of visor misting. The misting is often caused by physical exertion or tense situations such as when dealing with unexploded ordnance (UXO) and can seriously hamper the security professional. While there are a number of solutions, none has been entirely satisfactory. One example is where a thin coating of a conductive compound, such as indium tin oxide, ITO, deposited on the surface of the visor, passes an electric current whose heating effect drives off the condensation. This is widely used in civil applications, such as close to or behind the LCD screens of forecourt fuel pumps or for kiosks designed for open-air locations. While small imperfections in the optical quality of the film are of little consequence in such applications, when placed close to the eye, as in a security visor, they become more noticeable. More importantly, as less than 100% of the incident light is transmitted through the ITO coating, a reflection of the wearer's own face is sometimes visible.