We present our in-situ experimental observations of dark spot growth in OLE
D devices using optical microscopy. In order to IN understand the formation
mechanism of dark spots, we employed silica particle to intentionally crea
te some predictable pinhole defects on the protective layer. We found a lin
ear growth of all dark spot as well as a linear correlation between growth
rate and area. These results indicate that dark spot formation is related t
o corrosion of the calcium or other materials with water and oxygen through
pinhole defects. Furthermore, we found a correlation between the degradati
on of entire devices and growth of all dark spots, which allows us to predi
ct the lifetime of entire devices. (C) 2001 Elsevier Science B.V. All right
s reserved.