Patent ID: 7848196

Claim:
A power determining method for determining a light emitting power of a light source upon recording information on an optical disk having a plurality of rewritable recording layers, the method comprising a step of: obtaining an optimum erasing power with respect to an optimum recording power by recording test data on the optical disk, wherein the step of obtaining the optimum erasing power includes erasing the test data using differing erasing powers after recording the test data on the optical disk using the optimum recording power, and obtaining the optimum erasing power based on an amplitude of a signal obtained from an area of the optical disk from which the test data are erased, and wherein the optimum erasing power is equal to an erasing power used when the amplitude of the signal obtained from the area from which the test data are erased establishes a predetermined relationship with an amplitude of a signal obtained from an unrecorded area of the optical disk.