Dual-emission lighting systems employing light guides with segmented light extraction patterns

An edge-lit illumination system, comprising:

• a planar light guide having a light input edge, a first major surface, an opposing second major surface, and a light extraction area;
• one or more light sources positioned in a proximity to the light input edge and configured to illuminate at least a portion of the light input edge;
• a housing covering the one or more light sources and at least a portion of the planar light guide adjacent to the light input edge;
• and
• a plurality of light extraction structures formed on the first major surface and distributed over the light extraction area in a two-dimensional pattern such that at least some individual ones of the plurality of light extraction structures are separated from one another and from all edges of the planar light guide by smooth and planar portions of the first major surface,
• wherein each of the plurality of light extraction structures comprises a light scattering material and has a size between 20 micrometers and 200 micrometers along a longest dimension, a total volume between 1,000 cubic micrometers to 100,000 cubic micrometers, and a maximum thickness between 1 and 15 micrometers,
• wherein the two-dimensional pattern is segmented into a plurality of areas having different areal densities of the light extraction structures, and
• wherein, when the one or more light sources are energized, the plurality of light extraction structures cause light to be emitted from both the first major surface and the opposing second major surface.