| 摘要 |
PURPOSE:To facilitate an easy asembling with small thickness for an optical head, by simplifying the related structures among members including a focusing lens, a solenoid, coil, a lens holding barrel, etc. CONSTITUTION:A focus control signal and a tracking control signal are obtained to a change of the diameter of a beam spot 25 and a position shift between an information track and the spot 25. Both control signals are supplied to a solenoid coil 4 and the 2nd solenoid coil 17 and move a lens holding barrel 1 or a frame 5 to control properly the spot 25. For the shift of the frame 5, an electrode 16 is provided inside the barrel 1 and outside the frame 5 and independently of the frame 5. Thus the thickness of a whole device is reduced, and the weight of the electrode is subtracted from the weight of the frame 5. This reduces the weight of the frame 5. |
