Patent ID: 8866145

Claim:
An organic light-emitting display device, comprising: a buffer layer on a substrate, the buffer layer including a plurality of insulating layers having different refractive indexes, and an uppermost insulating layer of the insulating layers having different thicknesses; an active layer of a thin film transistor overlapping a thick area of the uppermost insulating layer of the buffer layer, the active layer including side surfaces that are coplanar with side surfaces of the thick area of the uppermost insulating layer in a direction perpendicular to a surface of the substrate; a pixel electrode overlapping a thin area of the uppermost insulating layer; a gate electrode of the thin film transistor on the active layer; source and drain electrodes of the thin film transistor connected to the active layer, a gate insulating layer being between the gate electrode and the source and drain electrodes; an emission layer on the pixel electrode; and an opposite electrode facing the pixel electrode, the emission layer being between the opposite electrode and the pixel electrode, wherein: the uppermost insulating layer includes: a first region including the thin area, the first region corresponding to the pixel electrode, a second region including the thick area, the second region corresponding to the thin film transistor, and a lower surface that extends at substantially a same level through the first region corresponding to the pixel electrode and through an entirety of the second region corresponding to the thin film transistor, and each of the plurality of insulating layers of the buffer layer is under the active layer and the pixel electrode.