Bending line along overlapping layers in folding box

Claim 1

A folding box consisting of a first cut-to-size blank from non-transparent material, and a second cut-to-size blank from transparent stiff plastic foil, which extends over at least one box edge, a bending line provided in the plastic foil, second blank overlapping and being glued to the first cut-to-size blank on an inside surface of said first blank, wherein the overlap between the first and the second cut-to-size glanks exists also at at least one end of the bending line, and the bending line is continued in the first cut-to-size blank by a corresponding groove line, the bending line and groove line being approximately the same width and wherein a box edge of two box walls is formed by said bending line and said groove line, characterized in that the second blank is thinned-down to a fraction of the thickness of remaining portions of the second blank in an area along the bending line and directly adjacent to the bending line at the overlap between the first and the second blanks, the thinned-down area of the second blank extending over the entire width of the overlap.