Today there are thousands of applications of vacuum coating technologies. It is hard to realize that the industry is only about 70 years old. The vapor sources for vacuum coating are 100 to 150 years old but commercial uses did not start until the mid-1930s with the development of thermal evaporation in vacuum. The applications of vacuum coatings progressed from the simple single-layer coatings used for electrical, optical, and reflecting applications in the 1930s and 1940s to coatings for corrosion protection in the 1950s. In the 1950s coatings on flexible materials for packaging began to be used and “vacuum metallization” for decorative purposes became a big business. The advent of semiconductor technology and the need for electrically conductive metallization and passivation layers was a major impetus to vacuum coating. The “energy crisis” in the 1970s showed the need for energy-conservation coatings on large areas of glass and polymer webs. In the 1980s vacuum coatings for display applications, particularly transparent conductive oxides, became important, and in the 1990s hard coatings for tools and decorative applications became important new applications. In the future it is expected that vacuum coatings will continue to play a vital role in developing both existing and new products. An example are the optically variable interference/diffraction films that are fractured and used as pigments in ink to counter counterfeiting .