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US 2004/0174804 A1Published application
Optical recording medium
AssigneeTDK Corporation
InventorsHironori Kakiuchi, Hiroyasu Inoue
Life of this patent
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AssigneeTDK Corporation
InventorsHironori Kakiuchi, Hiroyasu Inoue
Estimating the term…
An optical recording medium includes a support substrate and two information recording layers, an information recording layer close to a light incidence plane through which a laser beam is projected including a first dielectric film, a second dielectric film and a recording layer disposed between the first dielectric film and the second dielectric film and a thickness of each of the first dielectric film and the second dielectric film being determined so as to be equal to or larger than D21 and equal to or smaller than D22, where D21 is smaller than D2, D22 is larger than D2, and D21 and D22 are determined in such a manner that the dependency X of light transmittance of the information recording layer close to the light incidence plane on the wavelength of a laser beam is smaller than 1.2·X2 when each of the first dielectric film and the second dielectric film has a thickness of D21 to D22, where X2 is the wavelength dependency corresponding to a second smallest thickness among a plurality of thicknesses at which the dependency X of light transmittance of the information recording layer close to the light incidence plane on the wavelength of a laser beam locally becomes minimal. According to thus constituted optical recording medium, it is possible to markedly reduce the dependency of light transmittance of the information recording layer close to the light incidence plane on the wavelength of the laser beam.
An optical recording medium comprising a support substrate and a plurality of information recording layers, at least one information recording layer other than an information recording layer farthest from a light incidence plane through which a laser beam is projected comprising a first dielectric film, a second dielectric film and a recording layer disposed between the first dielectric film and the second dielectric film and a thickness of at least one of the first dielectric film and the second dielectric film being determined so as to be equal to or larger than D21 and equal to or smaller than D22, where D21 is smaller than D2, D22 is larger than D2, and D21 and D22 are determined in such a manner that the dependency X of light transmittance of the information recording layer other than the information recording layer farthest from the light incidence plane on the wavelength of a laser beam is smaller than 1.2·X2 when at least one of the first dielectric film and the second dielectric film has a thickness of D21 to D22, where X2 is the wavelength dependency corresponding to a second smallest thickness among a plurality of thicknesses at which the dependency X of light transmittance of the at least one information recording layer other than the information recording layer farthest from the light incidence plane on the wavelength of a laser beam locally becomes minimal.
An optical recording medium comprising a support substrate and a plurality of information recording layers, at least one information recording layer other than an information recording layer farthest from a light incidence plane through which a laser beam is projected comprising a first dielectric film, a second dielectric film and a recording layer disposed between the first dielectric film and the second dielectric film, and at least one of the first dielectric film and the second dielectric film being formed of a mixture of ZnS and SiO2 so as to have a thickness of 100 nm to 130 nm.
Dependencies are inferred from the claim text.