PURPOSE: To form a vapor deposition film having desired spectral transmittance in good reproducibility, in forming the vapor deposition film to the surface of a substrate, by performing vapor deposition while measuring the spectral transmittance of a formed film.
CONSTITUTION: A resistance heating type boat 2 is placed in a vacuum container 1 and a stock material 3 to be vapor deposited is put in said boat 2. A current is supplied to the boat 2 to heat the same and the vapor deposition stock material 3 is melted and evaporated to form a vapor deposition film to the surface of a transparent substrate 4. During this operation, light with a specific wavelength from a light source 5 is allowed to pass through the substrate 4, to which a vapor deposition film is being formed, and a substrate 7, to which no vapor deposition film is adhered, simultaneously and the transmitted light thereof is measured by a measuring instrument 6. The vapor deposition film on the substrate 4 can be measured from the ratio of two transmitted lights and vapor deposition is stopped when desired spectral transmittance is obtained.
SAKAMOTO EIJI
YOKONO KOUJIROU
