Patent ID: 7092319

Claim:
A power calibration apparatus for an optical disc comprising: writing means for writing information for a test writing by emitting a laser light to a power calibration area on an optical disc; reading means for reading the information for the test writing written in the optical disc; a first calibration means for controlling writing by the writing means through changing in steps a writing power of the laser light for writing the information for the test writing, setting a stepwise changing amount to a non-dense degree, and identifying a calibration area which, among calibration areas divided by a non-dense unit on the optical disc, is divided by a dense unit instead of the non-dense unit; a first writing power calculation means for reading the information for the test writing written in the optical disc under the control of the first calibration means, and calculating a first writing power in accordance with read out information for the test writing; a second calibration means for setting, to the writing power of the laser light for writing the information for the test writing, the first writing power as an initial value, and by changing the first writing power by a dense degree through steps corresponding in number to that of the calibration areas divided by the dense unit, urging the writing means to write corresponding to the steps in number; and a second writing power calculation means for reading the information for the test writing written in the optical disc under the control of the second calibration means, and calculating a second writing power in accordance with the information for the test writing of a sample number corresponding to the number of the calibration areas.