Optical recording method, optical recording apparatus and optical storage medium

An optical recording apparatus for a phase-change optical storage medium having a beam-incident surface and a plurality of data layers provided over the surface, each data layer having at least a recording film, comprising:

• an encoder to modulate data to be recorded to generate modulated data;
• a mark-length generator to generate desired mark-length data based on the modulated data;
• a controller to determine whether to record the data to be recorded in a first data layer located most remote from the beam-incident surface among the data layers or a second data layer different from the first data layer and generate an instruction signal based on the determination;
• a focus and tracking controller to control focusing and tracking to the first or the second data layer, based on the instruction signal;
• and
• a recorder to emit a recording beam onto each data layer based on the mark-length data, thus forming a recorded mark carrying the data to be recorded in each data layer, based on the instruction signal in which,
• when forming a recorded mark in the first data layer, the recorder generates a first recording pulse sequence having at least a first recording pulse carrying a first erasing power and a first recording power rising from the first erasing power, and a first cooling pulse carrying a first bottom power lower than the first erasing power, and emitting a recording beam onto the first data layer, whereas
• when forming a recorded mark in the second data layer, the recorder generates a second recording pulse sequence having at least a second recording pulse carrying a second erasing power and a second recording power rising from the second erasing power, a second cooling pulse carrying a second bottom power lower than the second erasing power, and an erasing top pulse carrying an erasing top power higher than the second erasing power, and emitting a recording beam onto the second data layer.

A phase-change optical storage medium comprising:

• a beam-incident surface via which a light beam is incident;
• a plurality of data layers provided over the beam-incident surface, each data layer having at least a recording film, a first data layer being located most remote from the beam-incident surface among the data layers, and a second data layer being different from the first data layer;
• and
• a specific data area, at least stored in which is identification data that indicates usage of a first recording pulse sequence in forming a recorded mark in the first data layer or a second recording pulse sequence in forming a recorded mark in the second data layer, the first recording pulse sequence having at least a first recording pulse carrying a first erasing power and a first recording power rising from the first erasing power, and a first cooling pulse carrying a first bottom power lower than the first erasing power, the second recording pulse sequence having at least a second recording pulse carrying a second erasing power and a second recording power rising from the second erasing power, a second cooling pulse carrying a second bottom power lower than the second erasing power, and an erasing top pulse carrying an erasing top power higher than the second erasing power.