Information recording or reproducing device and recording or reproducing method

An information recording controlling method comprising:

• a mounting step in which a removable disk-shaped optical recording medium is set in place;
• a rotation driving step in which the set disk-shaped optical recording medium is rotated at a predetermined velocity;
• a pulse signal generating step in which N (N is a natural number) pulse signals are generated in a predetermined cycle while the disk-shaped optical recording medium is being rotated one full turn in the rotation driving step;
• a counting step in which there are counted the N pulse signals generated in the pulse generating step;
• a storing step in which an axial-runout amount detected in a predetermined radial position on the disk-shaped optical recording medium in timing of generation of the pulse signals in the pulse signal generating step is stored in correspondence with the count value counted in the counting step;
• a near-field light projecting step in which there is condensed a light beam of a predetermined wavelength modulated with information to be written to the information recording surface of the disk-shaped optical recording medium and emitted from a light source and the condensed light beam is projected as near-field light to the information recording surface from a near-field light projecting means located in a field near the information recording surface of the disk-shaped optical recording medium;
• a radial-position information detecting step in which there is detected radial-position information indicative of a radial position on the information recording surface of the disk-shaped optical recording medium being irradiated with the light beam from the near-field light projecting means;
• a gain generating step in which there is generated a predetermined gain corresponding to radial-position information detected in the radial-position information detecting step;
• an axial-runout amount reading step in which an axial-runout amount stored in the storing step is read correspondingly to the count of pulse signals counted in the counting step;
• a first controlling step in which a control signal is generated by multiplying the axial-runout amount read in the axial-runout amount reading step by the predetermined gain generated in the gain generating step to control the near-field light projecting means to follow the axial-runout amount;
• a return-light amount detecting step in which there is detected a return-light amount of the near-field light projected to the information recording surface;
• and
• a second controlling step in which the near-field light projecting means is controlled based on the linear characteristic of the return light amount of the near-field light detected in the return-light amount detecting step to keep a predetermined distance within the near field from the information recording surface.