MICROPRISM MATRIX

摘要

This invention relates to a microprism master mold which can be applied to the production of cube-corner type retroreflectors, especially in the form of a thin and flexible retroreflective sheeting, and permits the formation of microprisms having high brightness and excellent wide-angle properties. This microprism master mold comprises a plurality of flat sheets having two mutually parallel major surfaces and provided on one edge thereof with a series of V-shaped grooves having a bottom angle of about 90< DEG > and roof-shaped projections having a vertical angle of about 90< DEG > which are successively formed at a fixed repeating pitch and in a direction perpendicular to the major surfaces, the flat sheets being stacked so that the vertices of the roof-shaped projections formed on each flat sheet meet the bottoms of the V-shaped grooves formed on an adjacent flat sheet, and is characterized in that the microprism master mold includes two or more different types of roof-shaped projections and in that the thickness of each flat sheet is equal to 0.6-2.0 times the length of the shorter oblique sides of the roof-shaped projection.