| 摘要 |
<p>A magnetically actuated optical focusing device is provided. The focusing device comprises a housing with an optical component being displaceably and rotatably arranged therein. The optical component is ferromagnetically coupled, via an internal magnet arranged thereon, to an external magnet arranged outside of the housing, the external magnet being fixed to a focusing ring which is rotatably mounted on the housing. When the focusing ring is rotated, the ferromagnetic attraction between the magnets is sufficient to drive the internal magnet through a helical channel defined on the internal surface of the housing, thus causing the optical component to be longitudinally displaced within the housing. The helical channel exerts sufficient restraining force on the inner magnet so that the inner magnet remains in a particular position along the channel even if the ferromagnetic coupling between the magnets is broken down. Thus, any unintended adjustment of the optical component by an external force is reliably prevented.</p> |
