DIFFUSION BARRIER COATINGS HAVING GRADED COMPOSITIONS AND DEVICES INCORPORATING THE SAME

摘要

A composite article comprises a substrate (340) having at least a substrate surface and a graded-composition coating (350) disposed on a substrate surface. The composition of the coating material varies substantially continuously across its thickness. The coating (350) reduces the transmissio n rates of oxygen, water vapor, and other chemical species through the substra te (340) such that the composite article can be used effectively as a diffusion barrier to protect chemically sensitive devices (320) or materials. An organ ic light-emitting device (310) incorporates such a composite article to provide an extended life thereto.