| 摘要 |
PURPOSE:To read information at a high contrast ratio by incorporating a metal or semiconductor element, carbon and hydrogen or fluorine or both thereof into a recording film and providing a multiple interference effect thereto. CONSTITUTION:The recording film contains the metal or semiconductor element, carbon and hydrogen or fluorine or both thereof and has the film thickness at which the reflectivity by the multiple interference effect attains a max. value. The metal or semiconductor element is Te, Se, Bi, Ge, Sb, Sn, Pb, Ga, In or Ag. The reflectivity of the thin film by the multiple interference effect increases if the phase of the coefft. r1 of Fresnel reflection at the boundary face of the recording film 24/air 26 coincides with the phase of the coefft. r2, r3... of reflection of the light reflected by the boundary face of the film 24/the substrate 22. Said reflectivity decreases otherwise. The multiple interference effect is remarkable with elements of a small attenuation coefft. or compsn. in which the metal or semiconductor element is dispersed. The information is thereby read at the high contrast ratio.
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