Patent ID: 7215075

Claim:
An organic EL device comprising: a supporting substrate, a lower electrode, an organic EL layer, and an upper electrode, said lower electrodes, organic EL layer and upper electrode being formed sequentially on said supporting substrate, wherein said upper electrode is formed from a plurality of transparent electrode layers that have different refractive indices to one another, and wherein the plurality of transparent electrode layers constituting said upper electrode satisfy the conditions (A) n i−1 >n i >1 when i=2, and both n i+1 >n i >1 and n i−1 >n i >1 when i>2, and (B) (a) n i ×d i =(2y+1)×λ i /4, and (b) n i−1 ×d i−1 =(2z+1)×λ i /2, wherein i is an even number of at least 2, n i is the refractive index of the i th transparent electrode layer, n i−1 is the refractive index of the (i−1) th transparent electrode layer, n i+1 is the refractive index of the (i+1) th transparent electrode layer, d i is the thickness of the i th transparent electrode layer, d i−1 is the thickness of the (i−1) th transparent electrode layer, y is an integer of at least 1, z is an integer of at least 1, and λ i is the wavelength of light for which the reflectivity is to be reduced for the i th transparent electrode layer.