| 摘要 |
PROBLEM TO BE SOLVED: To extend the inside access range by reducing the change in the operational sensitivity or the linearity of a radial tilt even though an objective lens is shifted to the tracking direction or the focusing direction. SOLUTION: In at least one group of opposed magnets 10a, 10b for tilt and a tilt coil 5, when a lens holder 2A is located at the neutral position, a ratio of a gap between opposed surfaces of the respective magnets 10a, 10b for tilt and the tilt coil 5 to the thickness of the magnets 10a, 10b for tilt in the radial direction is made to be 1:2 or 1:3, and a ratio of the height in the direction of optical axis of the inner peripheral part of the tilt coil of at least one side to the height in the direction of optical axis of the magnets 10a, 10b for tilt arranged at the opposed position is made to be 1:1.5 or 1:4.
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