Patent EP0319037A2 successfully refreshed from Google Patents.
EP0319037A2
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EP
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Optical information recording medium
Assignee: Panasonic Holdings Corp
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Filing: 1988-12-02
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Granted: —
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Expires: 2008-12-02
Abstract
Abstract A rewritable optical information recording medium of phase-change type wherein the recording, erasing, reproduction and rewriting of information are effected by irradiation of a high density energy flux such as laser beams. With the aim of obtaining a high erasing ratio in overwriting using a single laser beam, a constitution of medium has been devised whereby the same temperature-rise profile can be obtained for both the recorded mark part and the unrecorded (erased) part of the recording film. For example, by selecting the film thickness of each layer such that the optical absorbance at the wavelength of irradiation light source is the same in both the recorded part and the unrecorded part, an erasing ratio of -30dB or more has been attained.
Inventors
- 👤 Noboru Yamada
- 👤 Ken'ichi Nagata
- 👤 Kenichi Nishiuchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 22:52
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/004; G11B7/0055; G11B7/00557; G11B7/24; G11B7/241; G11B7/242; G11B7/243; G11B7/2433; G11B2007/24302; G11B2007/24312; G11B2007/24314; G11B2007/24316; G11B7/252; G11B7/257; G11B2007/25705; G11B2007/25706; G11B2007/25716; G11B7/253; G11B7/2533; G11B7/2534; G11B7/258; G11B7/2595
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
45 words
An optical information recording medium provided with a recording layer capable of changing reversibly between two optically detectable states in response to light irradiation conditions, wherein the two states in said recording layer have the same optical absorbance at the wavelength of the irradiation light.
Claim 2
Dependent Claim
45 words
An optical information recording medium provided with a recording layer capable of changing reversibly between two optically detectable states in response to light irradiation conditions, wherein the two states in said recording layer have the same optical absorbance at the wavelength of the irradiation light.
Claim 3
Dependent Claim
57 words
An optical information recording medium provided with a recording layer capable of changing reversibly between a crystal phase and an amorphous phase in response to light irradiation conditions, wherein the optical absorbance corresponding to the wavelength of irradiation light in the crystal phase part is equal to or relatively higher than that in the amorphous phase part.
Claim 4
Dependent Claim
57 words
An optical information recording medium provided with a recording layer capable of changing reversibly between a crystal phase and an amorphous phase in response to light irradiation conditions, wherein the optical absorbance corresponding to the wavelength of irradiation light in the crystal phase part is equal to or relatively higher than that in the amorphous phase part.
Claim 5
Dependent Claim
90 words
An optical information recording medium provided with a recording layer capable of changing reversibly between two optically detectable states in response to light irradiation conditions, wherein when the quantity L of irradiation light and the quantity E of heat which are necessary for elevating the temperature of said two states a and b to a given temperature are correlated by the equation La ≧ Lb or Ea ≧ Eb, the optical absorbance A of the above two states at the wavelength of irradiation light satisfies the equation Aa ≧ Ab.
Claim 6
Dependent Claim
90 words
An optical information recording medium provided with a recording layer capable of changing reversibly between two optically detectable states in response to light irradiation conditions, wherein when the quantity L of irradiation light and the quantity E of heat which are necessary for elevating the temperature of said two states a and b to a given temperature are correlated by the equation La ≧ Lb or Ea ≧ Eb, the optical absorbance A of the above two states at the wavelength of irradiation light satisfies the equation Aa ≧ Ab.
Claim 7
Dependent Claim
61 words
An optical information recording medium according to Claim 3 provided with a recording layer capable of changing reversibly between a crystal phase and an amorphous phase in response to light irradiation conditions, wherein the optical absorbance corresponding to the wavelength of irradiation light in the crystal phase part is equal to or relatively higher than that in the amorphous phase part.
References Cited (Backward Citations)
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