| 摘要 |
PROBLEM TO BE SOLVED: To provide a means which changes over an objective lens to the one coping with any system of optical disk by using a part of the servomechanism. SOLUTION: A lens holder maintains plural pieces of objective lenses 26a and 26b on concyclic positions having different angles to the support axis, and is also provided with as many magnetic material members 40 and 41 as the objective lenses fixed adjacently to a coil 35 for tracking and correspondingly to the center positions of each objective lens 26a and 26b. The mutual magnetic attractive force of the magnetic material members 40 and 41 and the magnet for tracking 39 maintains each objective lens 26a and 26b at the center position where they are inserted in the optical path. Further, by a reverse current made to flow into the coil 35 for tracking in the state that one magnetic material member faces the magnet 39 for tracking, the lens holder 33 is moved so that the other magnetic material member faces the magnet 39 for tracking. |
