| 摘要 |
<p>PURPOSE:To realize an optical scanning device having a reflecting mirror rotating at high speed and stably. CONSTITUTION:A bearing device 30 of an optical scanning device is constituted of permanent magnets 31a, 31b, electromagnets 32a, 32b consisting of iron cores 321a, 321b and coils 322a, 322b and a voltage control circuit 33 to control voltage applied to the coils 322a, 322b. At the time when the number of rotation of a reflecting mirror 20 increases and exceeds a certain point, by changing voltage applied to the coils 322a, 322b of the electromagnets 32a, 32b, bearing rigidity of the bearing device 30 is changed. Consequently, as resonance frequency of a conical mode and a cylindrical mode becomes sufficiently lower than the number of rotation of the reflecting mirror 20, whirling of a rotation axis 22 is never excited.</p> |
