Patent ID: 6379743
Filing Date: 2002-04-30
Classification: C07C,H01L

Abstract:
A process for preparing an organic electroluminescent device having a transparent substrate, a transparent electrode layer, a metallic electrode layer, and an organic interlayer disposed between and in close contact with the electrode layers, the organic interlayer being comprised of an organic luminescent layer, an optional hole transport layer and a optional electron transport layer and containing an electronically active material dispersed in a matrix of polyimide of formula (I), characterized in thatthe organic interlayer is prepared by depositing the vapors of a dianhydride, a diamine and the electronically active material to form a polyimide precursor layer containing the active material dispersed therein; and thermally imidizing the polyimide precursor layer, comprising: repeating the steps of i) vapor deposition polymerization of a first dianhydride and a first diamine to fabricate a first polyimide precursor layer, ii) thermal imdization of the first precursor layer to fabricate a first polyimide layer, iii) vapor deposition polymerization of a second dianhydride and a second diamine to fabricate a second polyimide precursor layer, and iv) thermal imidization of the second precursor layer to fabricate a second polyimide layer, to form a distributed Bragg reflector having an alternately stacked structure of the first polyimide layer and the second polyimide layer having a refractive index lower than that of the first polyimide film, the distributed Bragg reflector being positioned between the transparent substrate and the transparent electrode: â€ƒwherein A is derived from the dianhydride; B is derived from the diamine; and n is an integer of 2 or higher.