| 摘要 |
PURPOSE:To provide a compact diaphragm driving mechanism without projecting a driving body in the radial direction. CONSTITUTION:The diaphragm driving mechanism is provided with a wheel with arrow-shaped spokes 5 turned against a diaphragm case 4 to change the diameter of an opening by plural diaphragm blades 3, an ultrasonic motor 1 having a laminated piezoelectric element 1c generating a high frequency vibration and a U-shaped elastic body composed of a base part 1a on which the laminated piezoelectric element 1c is fixed and beams 1b and 1b' parallelly projected from both end parts of the base part 1a, arranged in front of tame wheel 5 along its optical axis and allowing a contact part 1d to contact with the front surface of the motor 1, a holding member 6 holding the ultrasonic motor 1 and a press-contacting mechanism energizing the holding member 6 by an energizing member 7 passing through a screw 11, so that the motor 1 is pressed to contact with the wheel 5. |
