Patent ID: 6120280
Filing Date: 2000-09-19
Classification: B29C,B29D,B29L,G02B,Y10S

Abstract:
A microprism master mold comprising 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.degree. and roof-shaped projections having a vertical angle of about 90.degree. which are successively formed at a fixed repeating pitch and in a direction perpendicular to the major surfaces, said 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, characterized in that said microprism master mold includes two or more different 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.