ABSTRACT
This chapter discusses the optical thin films that have a thickness on the order of wavelengths so that optical interference takes place. The film is generally deposited on a glass, crystal, semiconductor, plastic, or flexible foil substrate such that the characteristics of the incident light are changed. The films can be composed of metallic or dielectric materials or a combination of the two. The characteristics changed include the transmittance, reflectance, polarization, absorption, scattering, and phase. Various monitoring methods such as time counting, color recognition, quartz monitoring, and optical monitoring have been developed to control thickness during thin-film deposition. Optical monitoring is generally used in the manufacturing of optical thin-film filters. Error analysis shows that the monitoring plate must be precoated for error compensation. Several numerical methods and the optimum trigger point method have been developed to improve the performance, sensitivity, and compensation associated with the turning point method and the level methods.
