| 摘要 |
PURPOSE:To accurately record and erase information by providing a position detecting means for an optical head in the radius direction of a disk and a memory to store the optimum value of a current to be permitted to flow on a bias magnet, and permitting the current of the optimum value to flow on the bias magnet corresponding to the leakage flux of a device. CONSTITUTION:A memory 20 is provided which stores the optimum value of the current to be permitted to flow on the bias magnet at each position of an optical head in the radius direction of the disk calculated from the distribution of the leakage flux of the device in advance. And the position of the radius direction of the disk of the optical head 13 is detected by the position detecting means, and the optimum value of the current to be permitted to flow on the bias magnet 16 at each position of the optical head 13 in the radius direction of the disk calculated from the distribution of the leakage flux of the device stored in the memory 20 in advance is permitted to flow on the bias magnet 16. In such a way, it is possible to eliminate the influence of the leakage flux, and to approach magnetic flux density to the optimum magnetic flux density on the recording plane of the disk, and to record and erase the information accurately. |
