Generating Sub-nanometer Displacement Using Reduction Mechanism Consisting of Torsional Leaf Spring Hinges

Abstract

Recent demand on the measurement resolution of precise positioning comes up to tens of picometers. Some distinguished researches have been performed to measure the displacement in picometer order, however, few of them can verify the measurement performance as available tools in industry. This is not only because the picometer displacement is not yet required for industrial use, but also due to the lack of standard tools to verify such precise displacement.We proposed a displacement reduction mechanism for generating precise displacement using torsional leaf spring hinges (TLSHs) that consist of four leaf springs arranged radially. It has been demonstrated that a prototype of the reduction mechanism was able to provide one-nanometer displacement with 1/1000 reduction rate by a piezoelectric actuator. In order to clarify the potential of the reduction mechanism, a displacement reduction table that can be mounted on AFM stage was newly developed using TLSHs. This paper describes the design of the reduction mechanism and the sub-nanometer displacement performance of the table obtained from its dynamic and static characteristics measured by displacement sensors and from the AFM images.

Development of a piezo-driven 3-DOF stage with T-shape flexible hinge mechanism

“…In order to improve the motion accuracy, there are a variety of flexure hinges have been proposed and utilized in the positioning system, including notch-type hinge [1][2][3], leaf-spring hinge [4][5][6], right elliptical hinge [7], V-shape flexure hinge [8], cross-axis flexural pivots [9][10][11], split-tube flexural pivots [12], cartwheel hinges [13][14][15][16][17], and so on. Among the proposed flexure hinges, the notch-type hinge and leaf-spring hinge are the most popular and widely utilized in precision positioning system.…”