Patent ID: 7649211

Claim:
A light emitting element comprising: a first layer between a first electrode and a second electrode, and a second layer between the first electrode and the second electrode, wherein the first layer includes a first light-emitting organic compound and an organic compound having a hole-transporting property, wherein the second layer includes a second light-emitting organic compound and an organic compound having an electron-transporting property, wherein the first layer is formed in contact with the second layer, and is located between the second layer and the first electrode, wherein the first light-emitting organic compound and the organic compound having a hole-transporting property are mixed, wherein the second light-emitting organic compound and the organic compound having an electron-transporting property are mixed, wherein the first light-emitting organic compound and the second light-emitting organic compound are the same compound, and wherein the organic compound having the hole-transporting property and the organic compound having the electron-transporting property comprises at least one of a tricyclic condensed aromatic compound, a tetracyclic condensed aromatic compound, a pentacyclic condensed aromatic compound, and a hexacyclic condensed aromatic compound.