Patent ID: 7294960

Claim:
An organic EL device comprising: a plurality of organic EL elements, each of the organic EL elements having a pair of electrodes and functional layers, the functional layers including at least a light-emitting layer and a hole injection/transport layer interposed between the pair of electrodes, wherein one organic EL element has an organic metal compound layer and the other organic EL elements have no organic metal compound layers and a material of the hole injection/transport layer in the one organic EL element is different from the hole injection/transport layers in the other organic EL elements; wherein both a material for forming the hole injection/transport layers of the one organic EL element and a material for forming the hole injection/transport layers of the other organic EL elements comprise a mixture of 3,4-polyethylenedioxythiophene and polystyrene sulfonic acid, and wherein the mixing ratio of 3,4-polyethylenedioxythiophene and polystyrene sulfonic acid in the mixture in the one organic EL element is different from that in the other organic EL elements.