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AssigneesHitachi, Ltd., Hitachi Maxell, Ltd.
InventorsMotoyasu Terao, Tetsuya Nishida, Yasushi Miyauchi, Akemi Hirotsune
Estimating the term…
An optical disk apparatus using an optical disk in which a layer (a reflectivity adjustment layer) in which the optical constants are changed by melting at the time of irradiation of light is provided separately from a recording layer using a phase change, and the reflectivity at a portion having a high reflectivity on the recording track is 40% or lower at the time of irradiation of strong light, and the reflectivity at the same portion is 60% or higher at the time of irradiation of weak light, wherein when the laser power is set to a power which is higher than the power at which the optical constants of the reflectivity adjustment layer are greatly changed at the time of rewriting and at which a high melting-point component is not melted, remaining of an unerased portion during rewriting due to a difference in reflectivity between the written mark portion and the other portions can be prevented and the possible number of rewritings can be increased, and hence an optical disk which has a high recording sensitivity, can be read by a CD player or others, and can be rewritten by overwriting and an optical disk apparatus using it can be obtained.
An optical recording medium which is formed on a substrate directly or via a protective layer and records and reads information by a change in a recording layer which is caused by irradiation of a laser beam, wherein said optical recording medium has a reflectivity adjustment layer separate from the recording layer, and the optical constants of the reflectivity adjustment layer are changed by irradiation of light and the reflectivity at the time or irradiation of weak light is relatively higher than the reflectivity at the time of irradiation of strong light, wherein
An optical recording medium having a property that when a high-power laser beam is irradiated, the reflectivity reduces greatly and when the power of the laser beam is lowered, the reflectivity returns to a high value, wherein the information for setting the read laser power to an intermediate value between the laser power at which the information recorded on said optical recording medium changes while a laser beam spot passes on said optical recording medium once and the lowest laser power down to which the reflectivity of said optical recording medium changes to a low value is written on said optical recording medium,
An optical recording medium having a property that when a high-power laser beam is irradiated, the reflectivity reduces greatly and when the power of the laser beam is lowered, the reflectivity returns to a high value, wherein the information for setting the read laser power at a value lower than the lowest laser power down to which the reflectivity of said optical recording medium changes to a low value is written on said optical recording medium,
An optical recording medium having a property that when a high-power laser beam is irradiated, the reflectivity reduces greatly and when the power of the laser beam is lowered, the reflectivity returns to a high value, wherein said recording medium includes a test-writing zone partially,
An optical recording medium which is formed on a substrate directly or via a protective layer and records and reads information by a change in a recording layer which is caused by irradiation of a laser beam, wherein said optical recording medium has a reflectivity adjustment layer separate from the recording layer, and the optical constants of the reflectivity adjustment layer are changed by irradiation of light and the reflectivity at the time or irradiation of weak light is relatively higher than the reflectivity at the time of irradiation of strong light,
An optical recording medium which is formed on a substrate directly or via a protective layer and records and reads information by a change in a recording layer which is caused by irradiation of a laser beam, wherein said optical recording medium has a reflectivity adjustment layer separate from the recording layer, and the optical constants of the reflectivity adjustment layer are changed by irradiation of light and the reflectivity at the time or irradiation of weak light is relatively higher than the reflectivity at the time of irradiation of strong light, wherein
An optical recording medium which is formed on a substrate directly or via a protective layer and records and reads information by a change in a recording layer which is caused by irradiation of a laser beam, wherein said optical recording medium has a reflectivity adjustment layer separate from the recording layer, and the optical constants of the reflectivity adjustment layer are changed by irradiation of light and the reflectivity at the time or irradiation of weak light is relatively higher than the reflectivity at the time of irradiation of strong light, wherein
An optical recording medium which is formed on a substrate directly or via a protective layer and records and reads information by a change in a recording layer which is caused by irradiation of a laser beam, wherein said optical recording medium has a reflectivity adjustment layer separate from the recording layer, and the optical constants of the reflectivity adjustment layer are changed by irradiation of light and the reflectivity at the time or irradiation of weak light is relatively higher than the reflectivity at the time of irradiation of strong light, wherein
An optical recording medium Which is formed on a substrate directly or via a protective layer and records and reads information by a change in a recording layer which is caused by irradiation of a laser beam, wherein said optical recording medium has a reflectivity adjustment layer separate from the recording layer, and the optical constants of the reflectivity adjustment layer are changed by irradiation of light and the reflectivity at the time or irradiation of weak light is relatively higher than the reflectivity at the time of irradiation of strong light, wherein
Dependencies are inferred from the claim text.