| 摘要 |
PROBLEM TO BE SOLVED: To reproduce the data without dividing into parts by displacing a groove in the direction of a groove width according to a specified displacement frequency and nearly fixing a groove width ranging a whole periphery excepting a zone boundary. SOLUTION: Plural zones z are formed successively concentric circularly from an inner periphery toward an outer periphery in a recording area R having a radius r on an optical disk A, and this recording area R is divided concentric circularly by respective zones z. A wobble frequency minutely displacing (wobbling) all grooves in respective divided zones z in the radial direction is fixed. The wobbled groove width making a boundary Sb of each zone a start position of a start line Sc becomes the same phase in each zone z. Then, since this disk A is rotated always at the number of fixed disk revolution, the single wobble frequency decided at every zone z is increased stepwise in proportion to the radial direction according to that. |
