Patent ID: 7292514

Claim:
An apparatus for recording information in a write-once-read-many type information recording medium by partially changing a phase of a recording layer by irradiation of a beam to form marks, wherein the apparatus modulates the beam to form a pulse train, the pulse train comprising: a multi pulse section including, in a portion where the mark is formed, a single pulse or a plurality of pulses each having a first power level a, and a pulse having a second power level b (b<a) between the adjoining pulses of the first power level a if the multi pulse section includes the plurality of pulses of the first power level a; a heat blocking pulse having a third power level c (c<a) immediately after the multi pulse section; and a bias section having a fourth power level d between the heat blocking pulse and a succeeding multi pulse section, and the pulse train being so formed that a time length tc of the heat blocking pulse and a reference clock cycle Tw of a signal to be recorded satisfy a relation: tc≧Tw, and the third power level c and the fourth power level d satisfy a relation: c<d.