| 摘要 |
PURPOSE:To correct focusing and tracking errors with high precision in simple constitution by allowing two piezoelectric elements, which support a movable element in the radial direction, to move finely the movable element in the radial direction and allowing one piezoelectric element, which supports the movable element in the axial direction, to move finely the movable element in the axial direction. CONSTITUTION:Piezoelectric elements 205 for driving in the radial direction are so controlled that one of them is contracted when the other is expanded, thereby moving an objective lens in the radial direction to correct the tracking error. A voltage is applied to a piezoelectric element 206 for driving in the axial direction to move the objective lens vertically, thereby correcting the focusing error. |
