| 摘要 |
PURPOSE:To excellently an optical system without causing resonance when it is driven by providing two supporting means which movably support an optical system holding means in different directions and directly connecting the pivot bearing of the second supporting means to one of bearing of the second supporting means to one of bearing holding members which constitute the link mechanism of the first supporting means. CONSTITUTION:When an electric current is conducted in a coil 88, the interaction of magnetic fields made by permanent magnets 54a and 54b vertically rocks a part consisting of pivot shafts 74a, 74b, 74c and 74d, pivot bearings 78a and 78b, an objective lens holding body 76, an objective lens 80, coils 86 and 88 through wires 72a, 72b, 72c and 72d by the turn around shafts 70a and 70b and autofocusing is executed. In response to the current conducting in the coil 88, the objective lens holding body 76 shifts upwards and respective wires tilt from the horizontal level. The upper end of the objective lens holding body 76 is positioned at a distance L2 from a recording medium 90. Thus, a parallel link mechanism causing the optical shaft of the objective lens 80 from falling, whereby the lens focuses automatically.
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