An optical isolation structure is incorporated into a display between the display elements and the transparent substrate for the display elements. The optical isolation structure reflects light rays within the substrate that impact the structure at high angles relative to normal to the structure, thereby permitting the substrate to be used as an integrated light guide for distributing light over the display from a light source on the edge of the substrate. The optical isolation structure may include a single layer having an index of refraction less than the substrate or a plurality of thin-film interference layers.