In a retroreflective display device comprising at least a
surface-protective layer, information display layer, retroreflective
layer and a back-protective layer, on or between these layers radio
frequency identification unit or units enclosing radio frequency
identification integrated circuit or circuits are disposed, and
communication antenna or antennas which are connected to said radio
frequency identification integrated circuit or circuits are installed. At
the back of the retroreflective layer an illuminator is disposed. The
retroreflective layer is retroreflective to the light coming from the
front of the sign and is transmissive to the light from the interior of
the sign.