| 摘要 |
PURPOSE:To adjust finely the optical axis of a reading lens to an attitude vertical to the recording face of a disc by supporting a coil assembly, where coils are so wound that coil axes are orthogonal to one another, and the reading lens freely movably by a supporting member. CONSTITUTION:Coils 32-34 are wound around a bobbin 21 consisting of a nonmagnetic body so that coil axes are orthogonal to one another, and a reading lens 36 and a magnetic flux repeating core 31 are held in the bobbin 21. Upper and lower casings 45 and 45' are matched to each other through spacers 43 attached to front end parts of arm parts of elastic supporting bodies 41, 41' set to the top and the bottom of the bobbin, and the bobbin 21 is stored freely movably in the space between casings. The magnetic flux outputted from a magnetic circuit 52 of casings is orthogonal to the coil 32, and the magnetic flux from the repeating core 31 is orthogonal to coils 33 and 34, and there is no difference of magnetic flux density between coil windings, and the coil driving force is uniform in the vertical direction, the horizontal direction, and the longitudinal direction. Thus, the optical axis of the reading lens 36 is so adjusted that it takes always the attitude vertical to the recording face of the disc. |
