MULTI-LAYERED DIELECTRIC FILM STRUCTURE OF OPTICAL DEVICE

PURPOSE:To obtain an optical device which permits easy inspection of a wavelength characteristic and has high quality by forming a pseudo adhesive film consisting of a dielectric film on the outermost layer in the stage of forming multi-layered dielectric films. CONSTITUTION:Dielectric films 3, for example, quartz (SiO2) (1.46 refractive index) and dielectric films 4, for example, titanium oxide (TiO2) (2.3 refractive index) having the refractive indices different from each other are alternately deposited and laminated by evaporation on the surface of a glass substrate 2 having 1.5 refractive index by which a desired characteristic is obtd. A dielectric having the refractive index approximately equal to the refractive index of an optical adhesive agent, for example, a dielectric film consisting of quartz (SiO2) (1.46 refractive index) is deposited by evaporation to a desired thickness as thick as about several hundred times of light wavelength on the outermost layer of the films 5 by which a pseudo-adhesive film 8 is formed.