Patent attributes
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.
