| 摘要 |
PURPOSE:To keep magnetic field strength for the fluctuation of a disk or the temperature change of a coil, etc., constant, by providing a magnetic circuit yoke to generate a perpendicular magnetic field, a coil, a voltage impression circuit and a control circuit part to control the magnetic field strength so as to be kept almost constant on a magneto-optical recording disk medium. CONSTITUTION:The magnetic circuit yoke 7 to generate the perpendicular magnetic field having an impression magnetic field area exceeding the scan area of an optical head 13, coils 8 and 9 arranged in the magnetic circuit yoke 7, the voltage impression circuit to drive the coils 8 and 9 with a current with both polarity by the switching of voltage, and the control circuit part to control the magnetic field strength on the magneto-optical recording disk medium 11 so as to be kept almost constant are provided. Thereby, it is possible to keep the magnetic field strength for the change of the resistance of the coil due to the temperature change or the fluctuation of the disk almost constant, to keep the amplitude to noise ratio of the carrier signal of a recording and reproducing signal constant and at a high level, and to suppress temperature rise in the inside of a magneto-optical recording and reproducing device. |
