| 摘要 |
PURPOSE:To hold a distance between a recording medium and a bias magnetic field generating device at a fixed level by utilizing a focus error signal generated from an AF circuit in an optical head for the positioning of the focusing direction of the device. CONSTITUTION:When a recording or erasing command is outputted from a host computer 1, a drive controller 3 moves the optical head 6 to a prescribed track and a prescribed sector and drives a semiconductor laser with recording or erasing power. Interlocking with the operation, a signal for selecting a coil corresponding to the position is outputted from a drive selector 4 to the bias magnetic field generating device 5 and the coil is modulated in accordance with a recording signal at the time of recording, and at the time of erasing allowed to generate a magnetic field in a fixed direction. After calculating and adjusting an autofocusing signal by an impressed voltage adjusting circuit 9, the optical head 6 supplies the adjusted autofocusing signal to an interval adjusting means in the device 5 by an AT/AF (autotracking/autofocusing) circuit 8. Consequently, by distance between the disk 10 and the device 5 is easilly held at the fixed value. |
