Internally illuminated retroreflective signs

Claim 1

An illuminated sign comprising a box-like enclosure closed over its whole periphery except for an opening at the front of the sign, a light source within the enclosure, a transparent plate supported in front of the light source and carrying a printed image that is readable at the front of the sign by light from the light source, and light-diffusing means and a retroreflective light-transmissive sheeting between the transparent plate and the light source, and extending uniformly over the whole area defined by said opening, said sheeting comprising an open-mesh fabric of filaments that are encased around their whole circumference over at least those parts of their length that define open spaces of the web by a monolayer of minute transparent microspheres, the microspheres being partially embedded in a layer of binder material coated on the filaments and partially exposed above the layer of binder material whereby at least at the front of the sign the microspheres are uncovered over the whole area of said opening and open to the air, and said microspheres being covered over their partially embedded surface with specular reflective material, said sheeting permitting the light source to illuminate the sign image through the open spaces of the fabric while also retroreflecting light incident on the sign so as to further illuminate the sign image.