Optical monitoring methods and their integration into automated vacuum coating systems are reviewed. Special attention is paid to monochromatic monitoring, the achievable monitoring accuracies, error compensation and error accumulation effects and the on line correction of trigger points. Finally a microprocessor control system with integrated monochromatic thickness monitoring is described.
"Automated Optical Coating Processes With Optical Thickness Monitoring", Proc. SPIE 0652, Thin Film Technologies II, (13 October 1986); doi: 10.1117/12.938350; https://doi.org/10.1117/12.938350