Patent ID: 7889427

Claim:
A tool for forming a textured surface on a light collimating and diffusing film, comprising: a cylindrical portion being disposed about a first axis and having an external textured surface and first and second ends, the cylindrical portion further having a first line disposed proximate the external textured surface extending substantially across the cylindrical portion substantially perpendicular to the first end, the cylindrical portion further having a second line extending around a periphery of the cylindrical portion substantially a predetermined distance from the first end, the external textured surface having a plurality of projecting portions and a plurality of trough portions, wherein each projecting portion extends outwardly from at least one adjacent trough portion, wherein the plurality of projecting portions and the plurality of trough portions define a plurality of slope angles, wherein between 7 to 20 percent of the slope angles on the external textured surface proximate the first line or the second line have a value between zero and five degrees.