Multifunctional Thin Film Stacks for Ophthalmic Lenses: The Importance of Interface Control

摘要

For the past decades, plastic lenses have been continuously replacing glass lenses for ophthalmic applications. Coatings on such lenses have to fulfill multiple requirements, including excellent scratch and shock resistance, elimination of unwanted reflections, and increased ease of cleaning. This implies the use of more and more sophisticated multilayer coatings that have to be applied by well-controlled industrial processes, using various technologies. Obviously, the microstructure of each layer, as well as the interfaces between layers, are crucial for guaranteeing the optimum durability of the final product. This paper reviews the functions and performance of the various interfaces in such coatings, both mechanical and optical. This includes a description of a "typical" product available today. Some tools that control interfaces, including the use of in situ stress measurements during growth, are discussed.