Patent ID: 7085215

Claim:
An optical recording method for recording mark length-modulated information with a plurality of recording mark lengths by irradiating a recording medium with a light, the optical recording method comprising the steps of: when a time length of one recording mark is denoted nT (T is a reference clock period equal to or less than 25 ns, and n is a natural number equal to or more than 2), dividing the time length of the recording mark 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, η 2 T in that order (m is a pulse division number; Σ i (α i +β i )+η 1 +η 2 =n; α i (1≦i≦m) is larger than 0; β i (1≦i≦m−1) is a real number larger than 0; β m is a real number larger than or equal to 0; and η 1 and η 2 are real numbers between −2 and 2); radiating recording light with a recording power Pw i in a time duration of α i T (1≦i≦m); and radiating recording light with a bias power Pb i in a time duration of β i T (1≦i≦m−1), the bias power being Pb i <Pw i and Pb i <Pw i+1 ; wherein the pulse division number m is 2 or more for the time duration of at least one recording mark and meets n/m≧1.25 for the time length of all the recording marks; when the same division number m is used for at least 2 recording marks with different n's, different recording mark length is formed by changing at least one of β 1 , β m−1 , and β m ; and when m is 3 or more, whichever condition from (a)˜(d) of the following is satisfied. (a) (α i +β i ) is held constant for 2≦i≦m−1, not dependent on i. (b) (α i +β i−1 ) is held constant for 2≦i≦m−1, not dependent on i. (c) α i is held constant for 2≦i≦m−1, not dependent on i. (d) α i is respectively equal for the same i in 2≦i≦m−1, wherein at least 2 recording marks are formed by the same division number m.