Optical recording medium, method of writing and erasing information using the same, and process of producing the same
AssigneeMitsubishi Chemical Corporation
InventorsMichikazu Horie, Takuya Uematsu, Masae Kubo
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Abstract
An optical recording medium having a recording layer which comprises an Sb—Te alloy containing excess amount of Sb over the vicinity of Sb70Te30 eutectic composition and shows reversible phase changes on light beam irradiation between a crystalline state and an amorphous state differing from each other in optical properties, a method of writing and erasing information using the same, and a process of producing the same are described.
Claims22
An optical recording medium having a recording layer which comprises an Sb—Te alloy containing excess amount of Sb over the vicinity of Sb70Te30 eutectic composition and shows reversible phase changes on light beam irradiation between a crystalline state and an amorphous state differing from each other in optical properties, wherein:
- the polycrystalline state after initial crystallization mainly comprises a substantially single phase composed of hexagonal structure which is preferentially oriented,
- said polycrystalline state has a columnar structure having grown in the same direction, and
- the reflectance R1 of a non-recorded region of said optical recording medium after initial crystallization and the reflectance R2 of an erased region of said optical recording medium after 10th overwriting satisfy relationship (1):
- ΔR (%)=2|R1−R2|/(R1+R2)×100≦10 (1)
A process of producing an optical recording medium having a recording layer mainly comprising a composition represented by formula:
- SbxTe1−x (0.75≦x≦0.9) and showing reversible phase changes between a crystalline state and an amorphous state differing from each other in optical properties, which comprises forming at least said recording layer on a substrate and crystallizing said recording layer for initialization by scanning with an elliptic light beam having a minor axis length of 0.5 to 5 μm in a direction agreeing with said minor axis of said elliptic light beam at a scanning speed of 20% or more and less than 50% of a maximum possible linear velocity for overwriting said recording layer.
Dependencies are inferred from the claim text.