A TWIN-TYPE PIEZO-DRIVEN TRANSLATION MECHANISM

A monolithic translation mechanism driven by two pairs of piezoelectri c stacks is described which was devised primarily for use in the scann ing tunneling microscope. A monolithic flexure-hinged linkage which su pports a moving platform 15 mm wide and 20 mm long, four piezoelectric stacks, and a base plate are glued together to form the mechanism. A X-Y translation stage is readily constructed by stacking one translati on mechanism on another. Static and dynamic characteristics of the mec hanism are considered in detail, and design formulae are presented. Ex perimental investigation confirms that the accuracy of motion of the m echanism can be improved by adjusting the applied voltages to the piez oelectric stacks. It is demonstrated that the yaw of the moving platfo rm produced by a 46 mum output displacement is reduced from 0.3 arcsec to less than 0.1 arcsec by adjusting the applied voltage to one of th e four piezoelectric stacks.