Optical density curve model for CD-R dye coating

The dye coating is the most important process in CD-R replication technique, because the coating result has a significant effect on the final disc quality. Optical density (OD) curve represents the result of dye coating. In this paper an optical density curve model for dye coating is discussed. It can be used as an analysis tool of many important parameters in the coating process, thereby control the disc quality. The optical density curve of the disc after coating is measured with the Dr Schenk and then divided into several sections to line-fitting. The new curve has 4 characteristic points and 3 characteristic line sections, which can be used to make process analysis.