A light emitting panel, film or substrate assembly includes an optically conductive panel, film or substrate having at least one light input surface defined by at least one edge of a slot, cavity, opening or hole in which at least one LED light source having a greater width than height is positioned adjacent to the light input surface for directing light into the panel, film or substrate. The LED light source is configured to generate light having an output distribution defined by a greater width component than height component, the height component substantially corresponding to or less than the thickness of the light input surface.