| 摘要 |
PROBLEM TO BE SOLVED: To suppress vibration of a disk-shaped recording medium caused by the resonance generated when rotated even when a disk substrate consisting of a low-stiffness material is used in the disk-shaped recording medium. SOLUTION: Such a disk substrate is used in the disk-shaped recording medium, as has <=7.0×103 kgf/mm2 Young's modulus, >=0.22 Poisson's ratio, <=2.55×10-10 kgf.sec2/mm4 mass density and <=3.5 inches diameter. When this disk-shaped recording medium is almost equal to, in flutter amplitude and in resonance frequency of the amplitude mode of the minimum order, or smaller than the glass substrate-used disk-shaped recording medium having 2.5 inches diameter and 0.635 mm thickness, the inequalities: t<=0.064 dc/2-0.22 and t>=0.064dc/2-0.58 (wherein t is the thickness (unit: mm) of the disk substrate; dc is the outside diameter (unit: mm) of a clamp holding the center part of the disk substrate) are satisfied to decide t in connection with dc.
|
