| 摘要 |
PURPOSE:To maintain the constant coercive force and vapor deposition rate of a thin metallic film by controlling the amt. of the gaseous oxygen to be introduced and the evaporation rate of a magnetic metal according to the light reflectivity on the surface of the thin metallic film and the boundary face between a substrate and the thin film as well as the light transmissivity of a magnetic recording medium. CONSTITUTION:Photoirradiation devices 8, 10 and reflected light receiving devices 9, 11 as well as a photoirradiation device 12 and a transmitted light receiving device 13 are provided between a cooling can 4 and a take-up roll 3. The light reflectivity on the surface of the thin metallic film formed by diagonal vapor deposition under introduction of the gaseous oxygen on the transparent high-polymer substrate and the boundary face between the substrate and the thin film and the light transmissivity of the thin ferromagnetic metallic film are detected by this constitution. The signals from the receiving devices 9, 11 enter reflectivity monitoring means 15, 14 which operate a control system 17 for a gas supplying means to control a valve 20 for supplying the gaseous oxygen. The signal from the receiving device 13 controls an electron beam generating source 5 via a transmissivity monitor means 18 and a control means 19 for the electron beam generating source.
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