A display device comprising: a first substrate comprising a main display area and a sub-display area, the sub-display area comprising a plurality of transmissive areas disposed between adjacent pixel areas, the pixel areas comprising a thin-film transistor on the first substrate; a planarization layer on the thin-film transistor; a first light emitting electrode on the planarization layer; a bank covering a part of the first light emitting electrode; a light emitting layer on the first light emitting electrode; and a second light emitting electrode on the light emitting layer and the bank, wherein each transmissive area comprises a transmissive hole penetrating the bank and the planarization layer, the display device further comprising: an encapsulation layer comprising a first inorganic layer on the second light emitting electrode, an organic layer on the first inorganic layer, a second inorganic layer on the organic layer, wherein the first inorganic layer and the organic layer fill the transmissive hole, characterized in that the display device further comprises a first buffer layer on the first substrate; a second substrate on the first buffer layer; and a second buffer layer on the second substrate, wherein an active layer of the thin-film transistor is on the second buffer layer, and wherein the second buffer layer protrudes further in a direction in which the second substrate extends toward the transmissive hole than the second substrate at the transmissive area. a first substrate comprising a main display area and a sub-display area, the sub-display area comprising a plurality of transmissive areas disposed between adjacent pixel areas, the pixel areas comprising a thin-film transistor on the first substrate; a planarization layer on the thin-film transistor; a first light emitting electrode on the planarization layer; a bank covering a part of the first light emitting electrode; a light emitting layer on the first light emitting electrode; and a second light emitting electrode on the light emitting layer and the bank, wherein each transmissive area comprises a transmissive hole penetrating the bank and the planarization layer, the display device further comprising: an encapsulation layer comprising a first inorganic layer on the second light emitting electrode, an organic layer on the first inorganic layer, a second inorganic layer on the organic layer, wherein the first inorganic layer and the organic layer fill the transmissive hole, characterized in that the display device further comprises a first buffer layer on the first substrate; a second substrate on the first buffer layer; and a second buffer layer on the second substrate, wherein an active layer of the thin-film transistor is on the second buffer layer, and wherein the second buffer layer protrudes further in a direction in which the second substrate extends toward the transmissive hole than the second substrate at the transmissive area. an encapsulation layer comprising a first inorganic layer on the second light emitting electrode, an organic layer on the first inorganic layer, a second inorganic layer on the organic layer, wherein the first inorganic layer and the organic layer fill the transmissive hole, characterized in that the display device further comprises a first buffer layer on the first substrate; a second substrate on the first buffer layer; and a second buffer layer on the second substrate, wherein an active layer of the thin-film transistor is on the second buffer layer, and wherein the second buffer layer protrudes further in a direction in which the second substrate extends toward the transmissive hole than the second substrate at the transmissive area.