Retardation layer and organic light-emitting device including the same

An organic light-emitting device comprising:

• a substrate;
• an organic light-emitting element disposed on the substrate and for displaying an image;
• a sealing member disposed on the organic light-emitting element;
• a retardation layer disposed on a first surface of the substrate, the organic light-emitting element, or the sealing member, and comprising an alkali oxide layer grown up to be inclined on the first surface;
• and
• a linear polarization layer disposed on a second surface of the substrate, the organic light-emitting element, the sealing member, or the retardation layer, and being disposed closer to an image display surface of the organic light-emitting device than the retardation layer.