Patent ID: 7532555

Claim:
An optical recording method in which a crystalline state of a phase-change recording layer of a rewritable optical recording medium having said phase-change recording layer is used as unrecorded/erased state, and information is recorded by forming recording marks in an amorphous state with various time lengths nT (where T is a reference clock period, and n is an integer not less than 2), characterized in that: (M-1) when a recording velocity is within a range of recording velocities at which recorded information in said rewritable optical recording medium can be rewritten, a plurality of recording marks with the time length of nT are formed; dividing said time length nT into η 1 T, α 1 T, β 1 T, α 2 T, β 2 T, . . . , α i T, β i T, . . . , α m T, β m T and η 2 T (where m is a pulse dividing number, i is an integer not less than 1 and not larger than m, Σ i (α i +β i )+η 1 +η 2 =n, α i (1≦i≦m) is a real number larger than 0, β i (1≦i≦m−1) is a real number larger than 0, β m is a real number not less than 0, and η 1 and η 2 are real numbers not less than −2 and not larger than 2) in this order, where said pulse dividing number m for at least one time length of the recording marks is not less than 2, and the every time length of recording marks satisfies n/m≧1.25; applying a recording beam having a recording power Pw i (1≦i≦m) during a time period of α i T; applying a recording beam having a bias power Pb i (1≦i≦m, Pb i <Pw i , Pb i <Pw i+1 ) during a time period of β i T; applying a recording beam having an erasing power Pe (Pe is a value not less than any values of m Pb i 's where 1≦i≦m, and is a value smaller than any values of m Pw i 's where 1≦i≦m) on the spaces between said plural recording marks; and (M-2) when said recording velocity is higher than the recording velocity at which recorded information in said rewritable optical recording medium can be rewritten, and when the phase-change recording layer is beforehand crystallized, a recording mark with a time length nT is formed with one block pulse in which a recording beam with a recording power PwH and a recording beam with a bias power PbH are applied.