| 摘要 |
PURPOSE:To enable the formation of larger magnetic fields and to improve driving sensitivity by forming plural coils which are provided on an optical system holding body without superposing the coils on each other and forming the magnetic fields so as to cross these coils. CONSTITUTION:The coil 26 for tracking is disposed below the coil 25 for focusing on the outside circumference of an objective lens holding body 21 in the state of not overlapping in the coils 25 for focusing at the nearly equally spacing from 4 pieces of the coils 25. The magnetic fields are, therefore, generated between permanent magnets 28a, 29a and an inside yoke 30a as well as between permanent magnets 28b, 29b and an inside yoke 30b. The objective lens holding body 21 can be turned vertically or laterally around a supporting shaft 34 by passing current to the coils 25 or coil 26 of the holding body 21, by which the driving control for focusing or tracking of the objective lens 20 is executed. The driving device for the optical system which is small in the current and has the excellent driving sensitivity is thereby obtd. and the driving sensitivity is improved.
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