Patent ID: 8864359

Claim:
A lighting element, comprising: at least one light source; and a planar lightguide comprising: a first layer of functional film; and a second layer of surface relief film formed on the first layer of functional film, the second layer of surface relief film including a plurality of groups of surface relief structures, wherein: a combined thickness of the first layer of functional film and the second layer of surface relief film is between 0.01 mm and 0.4 mm; the surface relief structures, of at least one group of the plurality of groups of surface relief structures, are on the order of 10 microns or less in height; one or more of: a number of groups of the plurality of groups of surface relief structures, an arrangement of surface relief structures in respective groups of the plurality of groups, or a size of surface relief structures in respective groups of the plurality of groups are varied to provide a desired outcoupling of light from the at least one light source; the first layer of functional film comprises roll stock and the second layer of surface relief film comprises roll stock; and the first layer of functional film and the second layer of surface relief film are laminated together.