Patent ID: 7794857

Claim:
An organic light emitting device array comprising organic light emitting devices having each emitting color, the organic light emitting devices each comprising a pair of electrodes, a hole transport layer, a light emitting layer and an electron transport layer, wherein the hole transport layer contacts the light emitting layer and is continuously disposed in all the organic light emitting devices; the light emitting layer contacts the electron transport layer; the electron transport layer is continuously disposed in all the organic light emitting devices; the light emitting layer has a guest material contained in a host material, wherein each of the organic light emitting devices has (i) an ionization potential difference of not more than 0.2 eV between a material constituting the hole transport layer and the host material and (ii) an electron affinity difference of not more than 0.2 eV between a material constituting the electron transport layer and the host material; and the host material comprises a) a material emitting a red color of the formula b) a material emitting green color of the formula c) a material emitting blue color of the formula