Nova Patents
EP0347801A2

Optical recording media and information recording and reproducing units.

Abstract

The present invention provides an optical recording medium using an amorphous-crystalline phase-­change for recording and erasing, wherein reflectivity of an optical recording medium-constituting recording film in an amorphous state is larger than that of the optical recording medium-constituting recording film in a crystalline state, or wherein absorptivity of an optical recording medium-constituting recording film in an amorphous state is smaller than that of the optical recording medium-constituting recording film in a crystalline state.

EP0347801A2, drawing sheet 1
Sheet 1 of 62

Term

Term ended

Projected expiry passed 19 June 2009, 17.3 years ago.

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43 claims: 6 independent, 37 dependent

  1. 1
    An optical recording medium using an amorphous-­crystalline phase-change for recording and erasing, where­in reflectivity of an optical recording medium-constitut­ing recording film in an amorphous state is larger than that of the optical recording medium-constituting recording film in a crystalline state.
  2. 7
    An optical recording medium using an amorphous-crystalline phase-change for recording and erasing, which satisfies Ras-depo. Ra Rx wherein Ras-depo. represents reflectivity of a recording film, in an as-deposited state, which constitutes the above recording medium, Rx represents reflectivity of the recording medium-constituting recording film in crystalline state and Ra represents reflectivity of the recording medium constituting recording film in amorphous state.
  3. 13
    An optical recording medium using an amorphous-­crystalline phase-change of recording and erasing, wherein absorptivity of an optical recording medium-constituting recording film in an amorphous state is smaller than that of the optical recording medium-constituting recording film in a crystalline state.
  4. 19
    An optical recording medium using an amorphous-­crystalline phase-change for recording and erasing, which satisfies Aas-depo. Aa Ax wherein Aas-depo. represents absorptivity of a recording film, in an as-deposited state, which constitutes the above recording medium, Ax represents absorptivity of the recording medium-constitut­ing recording film in a crystalline state and Aa repre­sents reflectivity of the recording medium constituting-­ recording film in an amorphous state.
  5. 25
    An optical recording medium using an amorphous-­crystalline phase-change for recording and erasing, wherein a recording film constituting the recording medium has a larger refractive index in an amorphous state than in a crystalline state and a smaller extinction coefficient in the amorphous state than in the crystalline state.
  6. 42
    An information recording and reproducing unit with an optical recording medium (19) according to one of the claims 1, 7, 13 or 19 comprising a laser beam source, a laser actuating circuit (21) to actuate the laser beam source, an optical system (13, 14) to focus a laser beam on an optical recording medium (19) and a detection cir­cuit (15) to detect an optical change on the optical re­cording medium.
Independent claims6