| 摘要 |
PURPOSE:To prevent damage by turning a hologram disc in a flat disc form as it is not using shaft driving but using the principle of operation of a linear motor to prevent stress due to the vibration of shaft and to obtain stable rotation at high speed rotation. CONSTITUTION:A ring 11 having channel shaped cross section is fitted to an outer circumference of a glass disc 10 and bonded. Plural magnetic substances 11a are fitted on the circumference of the ring 11 at a prescribed pitch. Further, an outer frame member 12 made of a magnetic substance and formed with a groove 12a at its inside and with the ring 11 inserted to the groove 12a is positioned to the outer circumference of the magnetic substance 11a with a gap. A tilted face having an angle of elevation in the direction of rotation is formed at the lower part of the magnetic substance 11a and a floating face is produced by rotation. A magnetic field generating coil 14 is wound on a comb tooth part 13a at the inside of a ring shaped iron core 13 so as to constitute a linear motor 15 using the outer frame member as primary side iron core and using the magnetic substance 11a as secondary side conductor. In conducting the magnetic field generating coil 14, the magnetic substance 11a is floated in the groove 12a and runs, allowing to rotate the glass disc 10 in high speed. |
