| 摘要 |
<p>PURPOSE: To offset electromagnetic forces unnecessary for a tracking control by composing a yoke member of an inner yoke and an outer yoke and folding a tracking coil to be formed so that it wraps the inner yoke. CONSTITUTION: A yoke member 15 is comprising an inner yoke 15a and two pairs of inner yokes 15b, and a tracking coil 17 integrated into one body with a lens holder 11 fixed via elastic holding members 13 is folded and formed so as to wrap front and rear surfaces and a side face of the yokes 15b. Due to this constitution, forces in the opposite direction to each other which act on both driving devices generating rolling to the holder 11 are canceled with each other when the holder 11 is moved in the tracking direction by the magnetic forces of the coil 17 and permanent magnets 14. Therefore, the cancellation of the magnetic forces unnecessary for the tracking control allows a lens holder position to be controlled without inclination and also extends a movable range of the lens holder.</p> |
