US Patent 7746756 Optical disc recording apparatus

An optical pickup is disposed which irradiates a laser beam onto an optical disc where a guide groove having characteristics of thermal interference (heat discoloration) is spirally formed. The optical pickup irradiates the laser beam along the guide groove to conduct one of data recording in which pits indicating a data length are formed, and visible-image formation in which a part of the optical disc is discolored. The laser beam irradiation position is controlled so that the data recording is conducted with starting from the inner peripheral side of the optical disc, and the visible-image formation is conducted with starting from the outer peripheral side of the optical disc.