OPTICAL THIN FILM AND ITS PRODUCTION

摘要

PURPOSE: To provide a process for producing an optical thin film capable of forming the optical thin film having high flawing resistance at a high speed by a sputtering method. CONSTITUTION: This process has a stage for forming the film on a substrate 2 by using granular MgF2 grains 3 of a grain size of 0.1 to 10mm as a target and throwing high-frequency electric power of >=2W/cm<2> to this target to generate plasma on the target while introducing gas contg. at least oxygen, then raising the temp. on the target surface by the plasma and sputtering both of the target and the vapor from the target and a stage for forming a surface protective layer which consists of a material contg. at least either SiO2 or Al2 O3 and has an optical thickness of 1 to 70nm by sputtering.