Method and device for embossing relief structures

Abstract

A method and device of embossing individually light-reflecting areas on a foil material, the method and device comprising feeding a foil material into a roller nip between a pair of rollers, wherein the pair of rollers comprises a first roller and a second roller, providing each of the first roller and second roller at their respective surfaces at least in a determined perimeter, respectively with a plurality of polyhedron-shaped positive projections and a plurality of negative projections complementary to the positive projections, whereby the plurality of positive projections are arranged according to a 2-dimensional grid. The plurality of polyhedron-shaped positive projections seamlessly and gaplessly join with those corresponding negative projections at the intended embossing of the foil material, hence enabling a homogeneously jointed embossed polyhedron-like shape in the foil. The method and device further comprise, for the purpose of providing a plurality of light-reflecting areas on the foil material, that are intended to reflect light in line with a table of reflectivity values for the 2-dimensional grid, according to an orientation and shape of each of the plurality of light-reflecting areas, and enabling a perception by the human eye of a user, of the intended reflected light on a determined wide viewing angle covered by reflected light from any of the light-reflecting areas, a step of adjusting for each of the plurality of light-reflecting areas to be provided, an orientation and shape of the corresponding positive projection in the 2-dimensional grid, that is intended to emboss the light-reflecting area.