| 摘要 |
PURPOSE:To achieve accurate irradiation with laser by fitting permanent magnets and a magnetic ring to a lens holder, by providing permanent magnets having energizing coils and magnetic bodies opposite to them, and by varying their energizing currents. CONSTITUTION:To the upper part and lower part of a reading lens holer 1, permanent magnets 3a-3d, and 7a-7d are fitted and to the intermediate part, a magnetic ring 11 is also fitted; and permanent magnets 4a-4d, and 7a-7d having prescribed energizing coils, and magnetic plates 12a-12c are arranged in opposition to them so that repulsion iss produced among them. For focus adjustment, a current is flowed through neither the upper nor lower energizing coil, and the current is flowed through the energizing coil 13a or 13b to move up and down to the holder 1, making the focus adjustment. For track correction time-axis adjustment, a current is flowed through the prescribed energizing coil to make the adjustment similarly. Consequently, irradiation with laser is performed accurately. |
