Patent ID: 8179034

Claim:
A light extraction film for use with an organic light emitting diode (OLED) device having a surface that outputs light, comprising: a flexible substrate substantially transmissive to light emitted by the OLED device; a structured layer of extraction elements disposed on the substrate and having a first index of refraction, wherein the extraction elements comprise a nanostructured surface of the structured layer on a side of the structured layer opposite the substrate, wherein the nanostructured surface comprises non-particle based features in the structured layer; a backfill layer comprising a material having a second index of refraction different from the first index of refraction, wherein the backfill layer forms a planarizing layer over the nanostructured surface, forming a planar surface on a side of the backfill layer opposite the nanostructured surface, wherein a substantial portion of the extraction elements are within an evanescent zone of the light output surface of the OLED device when the planar surface of the backfill layer is located against the light output surface of the OLED device, and wherein the structured layer and backfill layer are in sufficient proximity to the light output surface of the OLED device when the planar surface of the backfill layer is located against the light output surface of the OLED device in order to at least partially enhance the extraction of light from the light output surface; and an optical coupling layer located on the planar surface of the backfill layer, wherein the optical coupling layer comprises an adhesive providing for optical coupling between the light output surface of the OLED device and the backfill layer, wherein the backfill layer comprises a non-scattering nanoparticle filled polymer material.