| 摘要 |
PURPOSE: To provide an electromagnetic damping mechanism for a film surface moving type automatic focusing camera, capable of surely controlling the damping of a movable part and holding the position of the movable part, when it is not actuated by rocking between two positions around a rocking shaft with the application of positive and negative pulselike currents, so as to damp an FB movement and release the damping and holding of the position, even if a current is cut. CONSTITUTION: A negative pulse is applied to an electromagnetic damping part 11 and a damper 14 releases a damping rod 12, to release the locking of an optical axis unit B. A driving current is applied to a linear motor and the optical axis unit B starts to move for focusing. A position detecting signal from a linear encoder is received and when the unit B approaches a desired FB position, a positive pulse is applied to the electromagnetic damping part 11 and the damper 14 abuts against the damping rod 12, to apply the damping and cut the driving current. Then, the negative pulse is applied to release the damping and the driving current is applied. These operations are repeated to apply smooth damping to the unit B moved at a high speed and even if the current is cut the position can be held. |
