JPS645371A - Positioning mechanism - Google Patents

Abstract

PURPOSE:To conduct positioning on the order of less than mum with a high accuracy by reducing and transmitting a displacement of actuator to a positioned body via an elastic member. CONSTITUTION:When a voltage is applied from a driving source 20 to piezoelectric elements 11 of a displacement part 1, holding members 13 are displaced in the direction of the arrow 10 and parallel members 12 of the displacement part 1 are transformed and curved outward. This indicates the fact that when a spring body 9 is displaced by x in the direction of the arrow 10, the displacement of a piezoelectric element 11 can be reduced if said body 9 is displaced by y in the direction of the arrow 3. A displacement quantity x is computed from the distortion signal SH of a distortion gauge 15 by a first computer 16 and a displacement quantity y is computed from the signal SA of the displacement quantity x by a second computer 18. A control signal output part 19 gives a driving source 20 a signal SD for accurately positioning a positioned body 7 from the signal SC of the displacement quantity y. A voltage corresponding to said control signal SD is applied to the piezoelectric element 11, the spring body 9 is displaced by a given quantity in the direction of the arrows 3, 10, and the positioned body 7 is reduced to a final target position.