A display apparatus comprises a unit pixel, the unit pixel comprising: a first blue sub pixel (B1, B1', B1", B1"') comprising a first intermediate layer (18b-1, 18b-1', 18b-1", 18b-1'"), the first intermediate layer (18b-1, 18b-1', 18b-1", 18b-1"') comprising a first blue organic emission layer (18b-1a, 18b-1a', 18b-1a", 18b-1a"'); a second blue sub pixel (B2, B2', B2", B2'") comprising a second intermediate layer (18b-2, 18b-2', 18b-2", 18b-2'"), the second intermediate layer (18b-2, 18b-2', 18b-2", 18b-2'") comprising a second blue organic emission layer (18b-2a, 18b-2a', 18b-2a", 18b-2a'"); a green sub pixel comprising a third intermediate layer (18b-3), the third intermediate layer (18b-3) comprising a green organic emission layer (18b-3a); and a red sub pixel comprising a fourth intermediate layer (18b-4), the fourth intermediate layer (18b-4) comprising a red organic emission layer (18b-4a), wherein each of the first blue sub pixel (B1, B1', B1", B1'"), the second blue sub pixel (B2, B2', B2", B2'"), the red sub pixel, and the green sub pixel comprises a first electrode and a second electrode, the first intermediate layer (18b-1, 18b-1', 18b-1", 18b-1"'), the second intermediate layer (18b-2, 18b-2', 18b-2", 18b-2"'), the third intermediate layer (18b-3), and the fourth intermediate layer (18b-4) respectively disposed interposing the first electrode and the second electrode, wherein the first intermediate layer (18b-1, 18b-1', 18b-1", 18b-1"') and the second intermediate layer (18b-2, 18b-2', 18b-2", 18b-2"') have different thicknesses, and characterized in that the first blue organic emission layer (18b-1a, 18b-1a', 18b-1a", 18b-1a'") and the second blue organic emission layer (18b-2a, 18b-2a', 18b-2a", 18b-2a"') comprise different materials, wherein the first blue organic emission layer (18b-1a, 18b-1a', 18b-1a", 18b-1a"') includes a sky blue dopant selected from p-bis(p-N,N-diphenyl-aminostyryl)-benzene (DSA-Ph) and phenyl cyclopentadiene, and the second blue organic emission layer (18b-2a, 18b-2a', 18b-2a", 18b-2a"') includes a deep blue dopant selected from 4'-N,Ndiphenylaminostyryl-triphenyl (DPA-TP), 2, 5,2',5'-tetrastyryl-biphenyl and an anthracene-based derivative. a first blue sub pixel (B1, B1', B1", B1"') comprising a first intermediate layer (18b-1, 18b-1', 18b-1", 18b-1'"), the first intermediate layer (18b-1, 18b-1', 18b-1", 18b-1"') comprising a first blue organic emission layer (18b-1a, 18b-1a', 18b-1a", 18b-1a"'); a second blue sub pixel (B2, B2', B2", B2'") comprising a second intermediate layer (18b-2, 18b-2', 18b-2", 18b-2'"), the second intermediate layer (18b-2, 18b-2', 18b-2", 18b-2'") comprising a second blue organic emission layer (18b-2a, 18b-2a', 18b-2a", 18b-2a'"); a green sub pixel comprising a third intermediate layer (18b-3), the third intermediate layer (18b-3) comprising a green organic emission layer (18b-3a); and a red sub pixel comprising a fourth intermediate layer (18b-4), the fourth intermediate layer (18b-4) comprising a red organic emission layer (18b-4a), wherein each of the first blue sub pixel (B1, B1', B1", B1'"), the second blue sub pixel (B2, B2', B2", B2'"), the red sub pixel, and the green sub pixel comprises a first electrode and a second electrode, the first intermediate layer (18b-1, 18b-1', 18b-1", 18b-1"'), the second intermediate layer (18b-2, 18b-2', 18b-2", 18b-2"'), the third intermediate layer (18b-3), and the fourth intermediate layer (18b-4) respectively disposed interposing the first electrode and the second electrode, wherein the first intermediate layer (18b-1, 18b-1', 18b-1", 18b-1"') and the second intermediate layer (18b-2, 18b-2', 18b-2", 18b-2"') have different thicknesses, and characterized in that the first blue organic emission layer (18b-1a, 18b-1a', 18b-1a", 18b-1a'") and the second blue organic emission layer (18b-2a, 18b-2a', 18b-2a", 18b-2a"') comprise different materials, wherein the first blue organic emission layer (18b-1a, 18b-1a', 18b-1a", 18b-1a"') includes a sky blue dopant selected from p-bis(p-N,N-diphenyl-aminostyryl)-benzene (DSA-Ph) and phenyl cyclopentadiene, and the second blue organic emission layer (18b-2a, 18b-2a', 18b-2a", 18b-2a"') includes a deep blue dopant selected from 4'-N,Ndiphenylaminostyryl-triphenyl (DPA-TP), 2, 5,2',5'-tetrastyryl-biphenyl and an anthracene-based derivative.