An OLED apparatus including a substrate with a lower active layer thereon and including an oxide semiconductor for generating current in response to light; an etching prevention layer on an upper portion of the lower active layer and including a contact hole; a source/drain electrode on the etching prevention layer and electrically connected to the lower active layer through the contact hole; an upper charging electrode on the etching prevention layer and overlapping the lower active layer; a light emitting layer contacting the upper charging electrode for generating light; and a cathode electrode facing the upper charging electrode, wherein the light emitting layer is configured to be driven and emit light in response to a driving voltage applied to the upper charging electrode, and the lower active layer is configured to store current in the oxide semiconductor in response to the driving voltage applied to the upper charging electrode.