| 摘要 |
PROBLEM TO BE SOLVED: To stabilize the operation of an ultrasonic motor by improving a torque transmission mechanism interposed between a lens barrel and the ultrasonic motor in a lens driving device for a camera. SOLUTION: The lens driving device for the camera includes the ultrasonic motor consisting of a rotor 2 which rotates on its axis by revolution torque and a stator 1 to generate the revolution torque, a lens barrel 3 in which lenses 33 and 34 for the camera are mounted and can linearly be displaced in the optical axis Z direction of the lenses, and a transmission member 5 which converts the rotatory motion of the rotor 2 to the linear displacement of the lens barrel 3 and transmits the motion to the barrel. The transmission member 5 is connected to the rotor 2 in a freely movable state, and protects the rotor 2 from the variation of the load of the lens barrel 3 caused by the attitude difference of the camera. The transmission member 5 is engaged with the lens barrel 3 through a male helicoid gear 31 provided at one side and a female helicoid gear 51 provided at the other side, and converts the rotatory motion into the linear displacement. |
