| 摘要 |
<p>PURPOSE:To obtain the spatial advantage by forming and incorporating an ultrasonic motor whose center of rotation is aligned to the optical axis of a photographic lens annularly in a lens barrel. CONSTITUTION:An electrostrictive element 16 having an electrode is fitted to an elastic ring 15, and a rotor 17 is rotated by a surface wave generated by it. An internal cylinder 19 which holds a lens 13 is rotated by the key groove 17a of the rotor 17 through a pin 18. The internal cylinder 19 moves in an optical- axis direction while rotating. A pressure adjusting device 20 adjusts the contact pressure between the ring 15 and rotor 17. An electrostrictive element 22 provided with an electrode is also fitted to an elastic ring 23 for a controlling method of aperture, etc., and a pressure adjusting device 26 presses a rotor 24 against the ring 23. The rotation of the rotor 24 is transmitted to an aperture system 27 by a pin 25 to drive blades 14 through a known mechanism.</p> |
