| 摘要 |
PURPOSE:To attain an accurate radial direction control even with the fast revolving speed of a recording medium by increasing the cross section area of the elastic plate of the lens side in the couple of elastic plates holding a condenser lens more than the other side. CONSTITUTION:The couple of the 1st elastic plates 6, 7 moved in parallel wit the optical axis direction are provided between a lens holder 2 and the 2st holder 3, and the 2nd elastic plates 11, 12 moved vertically are provided between the 1st holder 3 and the 2nd holder 14. The cross section area of the 1st elastic plate 6 of the upper 2b of the condenser lens 1 is increased more than the cross section area of the lower side elastic plate 7. thus, the resistance to the vertical movement of the 1st elastic plates 6, 7 is reduced. Then, even when the revolving speed is fast, the frequency characteristic of the upper part 2b of the lens holder 2 is improved and the radial control is attained accurately.
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