| abstract |
A method of making an embossed optical sheet material (10) includes providing an optically anisotropic uniaxially oriented polymer substrate having a first surface and a second surface, a patterned tool with radiant energy Heated using radiant energy from a source, the pattern includes a plurality of parallel raised microstructures having a longitudinal direction, the tool against a first major surface of the polymer substrate parallel to the orientation direction of the polymer substrate. Press, soften the first major surface of the polymer substrate, emboss the groove-shaped microchannel (14) in the polymer substrate, cool the embossed polymer substrate, and separate the tool from the polymer substrate The orientation of the polymer substrate does not change across the polymer substrate and the first major surface. |