VMS (Variable Message Sign) technologies currently available are reviewed and the advantages of EEV's new sunlight readable LCD system discussed. EEV's VMS boards utilise fibre optic technology to rear illuminate an array of switchable LCD elements. A high level of contrast and luminance is achieved which can be read at distances in excess of 200m. Lamp brightness is continually monitored and adjusted. A light reflecting element operates in bright sunlight and the board can be read over a 12 degree cone of view. In the event of a failure all pixels darken. The automatic fault detection system is described. It is suggested that maintenance of EEV's LCD is easier than with other types of board. Details are given of the sign configurations available.
Samenvatting