| 摘要 |
PROBLEM TO BE SOLVED: To provide an electromechanical transducer driver in which an inertia element is not used. SOLUTION: The holding frame 21 of a lens L is supported by a guide shaft 22 so as to be able to slide along the guide shaft 22 freely. One end of a piezoelectric device 23 is bonded and fixed to the holding frame 21 and one end of a spring 24 is fixed to the other end of the piezoelectric device 23. The neighborhood 24a of the end of the spring 24 is pressed against the guide shaft 22 with a suitable pressure to compose a friction coupling part Ma. Friction F2 produced in the friction coupling part Ma is so set as to be substantially larger than the friction F1 produced in a sliding part Mb composed of the lens holding frame 21 and the guide shaft 22 (F2>>F1). When a drive pulse is applied to the piezoelectric device 23, if the piezoelectric device 23 shows a gentle expansion displacement, the friction coupling state of the friction coupling part Ma is maintained and the lens holding frame 21 is moved in an arrow direction (a) and, if the piezoelectric device 23 shows a quick contraction displacement, the lens holding frame 21 tends to stay at the present position by inertia and repulsion inertia exceeds the friction F2 and the lens holding frame 21 is not moved practically. |
