| 摘要 |
PROBLEM TO BE SOLVED: To provide a mirror frame capable of restraining the change of responsiveness caused by a posture difference when driving an optical system to advance/retreat. SOLUTION: A mirror frame device 1 has an annular fixed frame 2, and an annular moving frame 3 fit to the inner periphery part of the fixed frame 2 so as to advance/retreat and holding a photographic lens 4. An ultrasonic actuator 30 having a vibrator 35 functioning as a driving source for driving the moving frame 3 to advance/retreat is attached to the fixed frame 2, and further a posture sensor 14 detecting the posture (inclination) of the mirror frame device 1 is fixed there. If the mirror frame device 1 is in an inclined state when photographing, driving voltage applied to the vibrator 35 is increased/decreased according to output from the posture sensor 14, so that the change of load resistance to the advance/retreat movement of the moving frame 3 by gravity is eliminated, and the moving frame 3 is always made to advance/retreat at predetermined response speed. COPYRIGHT: (C)2007,JPO&INPIT |
