| 摘要 |
PURPOSE:To improve the adhesiveness between a transparent substrate and underlying protective layer by forming an Al2O3 layer thinner than the film thickness of the underlying protective layer between the transparent substrate and the underlying protective layer. CONSTITUTION:The underlying protective layer 11 consisting of AlN, etc., a recording layer 12 and a protective layer 13 are successively laminated by sputtering, etc., via the Al2O3 layer 20 on the transparent substrate 10 consisting of a plastic material such as polycarbonate. The layer 20 is formed to about several tens - several hundreds Angstrom film thickness. The film thickness (d) of the layer 11 or the total of said layer and the layer 20 is preferably adjusted to the relation d=lambda(2m+1)/4n, where (n) denotes the refractive index of the layer 11; lambda denotes the wavelength of the laser used; (m) denotes the natural number including 0. The adhesiveness of the layer 11 to the substrate 10 is improved and the cracking and exfoliation are made hardly generatable according to the above-mentioned method.
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