| 摘要 |
PURPOSE:To easily attach/detach a protection cover and to prevent a lens from damage by forming the protection cover by a magnetic substance and fitting the cover to an optical head by the magnetic force of a permanent magnet arranged in the head. CONSTITUTION:To control the vertical and horizontal movement of an objective lens, a radial servo coil 10, a focus servo coil 11 and permanent magnets 12, 13 relating to these coils are arranged in the optical head 1. The radial servo coil 10 and the permanent magnet 13 are arranged around the objective lens 7. When the protection cover 21 for the objective lens 7 is formed by a magnetic substance, the cover 21 is attracted to the magnet 13 and fitted to the optical head 1 under the status that the front cap 14 of the optical head 1 is coated with the exposed face of the objective lens. Thereby, the attachment/detachment of the cover 21 is easy, and since the cover 21 is not removed and dropped during transfer, the lens can be completely prevented from damage. |
