A twin-type piezo-driven translation mechanism

A monolithic translation mechanism driven by two pairs of piezoelectric stacks is described which was devised primarily for the mechanical scanner of STM (scanning tunneling microscope). The layout of the mechanism is symmetrical with respect to the center lines of the base plate. Each pair of piezoelectric stacks is cemented at the outer ends between two movable elements of the flexure-hinged linkage which supports a moving platform, and is also cemented at the center on both sides of aluminium alloy square blocks provided on both ends of the base plate. An X-Y translation stage is readily formed by stacking one translation stage on another. It is possible to improve the accuracy of motion of the moving platform by properly adjusting the applied voltage to each piezoelectric stack. Relationship is examined experimentally between the applied voltage and the accuracy of motion in order to attain a high precision translation mechanism. It is demonstrated that the yaw of the moving platform produced by a 46 μm output displacement of the moving platform is reduced from 0.3 arcsec to less than 0.1 arcsec by adjusting the applied voltage to one of four piezoelectric stacks.