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US 6,645,596 B1Granted
Optical disk and ultraviolet-curing composition for optical disk
AssigneeDainippon Ink and Chemicals, Inc.
InventorsKazuo Murakami, Takashi Kitsunai
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AssigneeDainippon Ink and Chemicals, Inc.
InventorsKazuo Murakami, Takashi Kitsunai
Estimating the term…
An object is to provide a technique of imparting durability which is equal to that of existing types of DVD-5 and DVD-10 as well as DVD-9 using gold or a silicon based compound as a semitransparent film, to a DVD obtained by bonding two substrates having information recording layers, respectively, on each outermost layer of which a thin film of silver or an alloy composed primarily of silver is formed. Using an optical disc wherein ratios of error rates before and after an environmental test at 80° C. and 85% RH for 96 hours is 10 or less, and an ultraviolet curable composition for optical disc wherein a water absorption rate of the cured coating film is 2.0 wt % or less and a water-vapor permeability at a film thickness of 50 μm is 70 g/m2·day or less, the object described above is achieved.
An optical disc comprising two substrates having information recording layers, respectively, a thin film of silver or an alloy composed primarily of silver being formed on an outermost layer of the information recording layer of at least one substrate, said two substrates being bonded together by an ultraviolet curable composition, wherein the optical disc is characterized in that ratios of error rates before and after an environmental test at 80° C. and 85% RH for 96 hours is or less.
An ultraviolet curable composition for optical disc, which is used in the production of an optical disc comprising two substrates having information recording layers, respectively, a thin film of silver or an alloy composed primarily of silver being formed on an outermost layer of the information recording layer of at least one substrate, said two substrates being bonded together by an ultraviolet curable composition, wherein the ultraviolet curable composition is characterized in that a water absorption rate of the cured coating film is 2.0 wt % or less and a water-vapor permeability at a film thickness of 50 μm is 70 g/m2·day or less.
Dependencies are inferred from the claim text.