| 摘要 |
PURPOSE:To perform precise positioning by forming a damper by utilizing the viscosity of fluid in an extremely small gap. CONSTITUTION:A precise moving base for an optical disk 4 has an optical head 5 fixed on a top plate 12 supported by parallel leaf springs 11 (11a and 11b). The gap G between a magnet 14 and the top plate 12 is filled with the magnetic fluid 16, which is held by magnetic force. For example, the position of a mirror 7 is detected by a position sensor such as a laser length measuring instrument, and the top plate 12 is driven by a piezoelectic oscillator 15 so as to correct an error in the detected position. When the top plate 12 moves by several mum, the gap G is expected to expand by several mum by a magnet holder 17 fixed to a bottom plate 13, but the force for suppressing the expansion is generated by the viscosity of the magnetic fluid 16. This force operates as damping force to shoten the settlement time of the displacement of the top plate 12. |
