A display device comprising: a substrate ; a switching element (T6) on the substrate; a pixel electrode (PE) disposed on the switching element (T6) and connected to the switching element (T6); a light emitting layer on the pixel electrode (PE); a common electrode on the light emitting layer ; and a sealing portion on the common electrode , wherein the sealing portion comprises: an organic layer ; and at least one first composite inorganic layer disposed between the organic layer and the common electrode , the at least one first composite inorganic layer comprises : a first inorganic layer (1-01) between the common electrode and the organic layer ; and a second inorganic layer (1-02) between the first inorganic layer (1-01) and the organic layer , and the first inorganic layer (1-01) and the second inorganic layer (1-02) have refractive indices different from each other, and the first inorganic layer (1-01) and the second inorganic layer (1-02) contact each other, and characterized in that the sealing portion comprises: a cover portion disposed on the common electrode , and an extension portion extending from the cover portion towards the substrate , wherein in a cross-sectional view the common electrode extends continuously below the cover portion and the extension portion , wherein the extension portion and the common electrode below the extension portion are inserted into the substrate , wherein a width of a first portion of the extension portion is greater than a width of a second portion of the extension portion , and the second portion is disposed closer to the cover portion than the first portion. a substrate ; a switching element (T6) on the substrate; a pixel electrode (PE) disposed on the switching element (T6) and connected to the switching element (T6); a light emitting layer on the pixel electrode (PE); a common electrode on the light emitting layer ; and a sealing portion on the common electrode , wherein the sealing portion comprises: an organic layer ; and at least one first composite inorganic layer disposed between the organic layer and the common electrode , an organic layer ; and at least one first composite inorganic layer disposed between the organic layer and the common electrode , the at least one first composite inorganic layer comprises : a first inorganic layer (1-01) between the common electrode and the organic layer ; and a second inorganic layer (1-02) between the first inorganic layer (1-01) and the organic layer , and a first inorganic layer (1-01) between the common electrode and the organic layer ; and a second inorganic layer (1-02) between the first inorganic layer (1-01) and the organic layer , and the first inorganic layer (1-01) and the second inorganic layer (1-02) have refractive indices different from each other, and the first inorganic layer (1-01) and the second inorganic layer (1-02) contact each other, and characterized in that the sealing portion comprises: a cover portion disposed on the common electrode , and an extension portion extending from the cover portion towards the substrate , a cover portion disposed on the common electrode , and an extension portion extending from the cover portion towards the substrate , wherein in a cross-sectional view the common electrode extends continuously below the cover portion and the extension portion , wherein the extension portion and the common electrode below the extension portion are inserted into the substrate , wherein a width of a first portion of the extension portion is greater than a width of a second portion of the extension portion , and the second portion is disposed closer to the cover portion than the first portion. <EOS>