DIRECTIONALLY IMAGED RETROREFLECTIVE SHEETING

摘要

Retroreflective sheeting comprising a monolayer of transparent glass microspheres partially embedded in a binder layer, a specularly reflective layer covering the back surfaces of the microspheres, and layer-formed images viewable only within a limited conical field of view, the images being provided by tiny ellipsoidal cavities in the microspheres, each opening through a back surface of the microsphere.