| 摘要 |
PROBLEM TO BE SOLVED: To prevent that the efficiency is lowered due to the heat of magnetic field generated in a thin film coil at the high modulation frequency, by transmitting the heat generated in the thin film coil to a coil supporting substrate in such a manner that the coil supporting substrate forming the thin film coil is formed by a member having a thermal conductivity higher than that of an objective lens. SOLUTION: On the main surface of the coil supporting substrate 44 confronted with the magneto-optical disk, a magnetic core 47 increasing the magnetic field efficiency which is formed through a transparent dielectric film 45 for preventing the reflection of a laser beam transmitting through this main surface, and a coil part 46 provided with the spiral thin film coil 48 which is formed on this core, are furnished. The thin film coil 48 is buried into an insulation layer for the protection, and a driving current is supplied from the outside of the spiral shape. Since the coil part 46 is provided on the coil supporting substrate 44 consisting of the member having high thermal conductivity, even though the thin film coil 48 generates the heat by the driving current, the heat is effectively transmitted to the coil supporting substrate 44 resulting no heat accumulation on the thin film coil 48, then the efficiency of the generated magnetic field is preventable from lowering. |
