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US 8,009,548 B2Granted
Optical recording medium
AssigneeTDK Corporation
InventorTakashi Kikukawa
Life of this patent
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AssigneeTDK Corporation
InventorTakashi Kikukawa
Estimating the term…
An optical recording medium of improved recording and reading characteristics, having both a read-only information recording layer and an information recording layer. The optical recording medium includes information recording layers capable of recording and reading by irradiation of laser light having a wavelength λ of 400 to 410 nm through an optical system having a numerical aperture NA of 0.8 to 0.9. In this medium, the information recording layers include at least a read-only information layer having information recorded in advance and an information recording layer different from the read-only information recording layer, the read-only information recording layer being capable of information recording of write-once type or rewritable type. The read-only information recording layer is stacked closest to a light incident surface of the laser light.
An optical recording medium comprising information recording layers capable of recording and reading by irradiation of laser light having a wavelength λ of 400 to 410 nm through an optical system having a numerical aperture NA of 0.8 to 0.9, wherein the information recording layers include at least a read-only information recording layer having information recorded in advance and an information recording layer different from the read-only information recording layer, being capable of information recording of write-once or rewritable type, the read-only information recording layer being stacked closest to a light incident surface of the laser light.
Dependencies are inferred from the claim text.