Patent ID: 7751294

Claim:
An information recording method for recording record marks according to multilevel data on an optical disk, comprising: performing test recording to determine an optimum recording power for recording pulses according to multilevel data, each pulse comprising a top pulse, an off pulse and an erasure pulse, the test recording comprising: first step of recording first test data for a plurality of top pulse widths Ton and monitoring reflected light intensity corresponding to the first test data for each top pulse width Ton to produce a respective monitoring result; second step of determining an optimum top pulse width Ton, from among the plurality of top pulse widths Ton, based on the monitoring results; third step of determining respective optimum off pulse widths Toff for multilevel data, based on the monitoring result of the optimum top pulse width Ton determined in said second step; and fourth step of recording second test data using the optimum top pulse width Ton and the optimum off pulse widths Toff determined in said second and third steps for a plurality of recording powers that are changed in sequence, monitoring reflected light intensity corresponding to the second test data for each recording power to produce a respective monitoring result, and determining the optimum recording power, from among the plurality of recording powers, based on the monitoring results corresponding to the second test data, wherein in said second step, the optimum top pulse width is determined from the following relational expression between the off pulse widths Toff and the reflected light intensity I with respect to the respective monitoring result for a top pulse width Ton: I=a·T off 3 +b·T off 2 +c·T off+ d wherein the top pulse width Ton in which the absolute value of the coefficient c is smallest is determined as the optimum top pulse width.