A collimating sheet, for use with a backlit display and the like, that
includes a substrate, a plurality of microlenses on the output side of
the substrate, a specularly reflective layer on the side of the substrate
opposite the microlenses, and a plurality of apertures in the reflective
layer in direct correspondence to the microlenses of the lens array. The
specularly reflective layer can be relatively thinner than a diffuse
reflective layer, which allows light to pass through the more readily.
One or more layers of dielectric can be placed on top of one or more
reflective material layers to further improves overall reflectivity.
Apertures are preferably made in the light-absorptive and reflective
layers with a laser ablation process wherein laser light illuminates the
output side of the film. The laser light is brought to a focus by the
lenslets of the lens array onto the light-absorptive layer, which then
ablates a hole or aperture into the light-absorptive and reflective
layer. In this way, the apertures are self-aligned with the lenslets.