title: Determination of the position and orientation of a flat piezoelectric micro-stage by moving the optical axis.
abstract: A moving optical axis measurement system with six degrees-of-freedom (DOF) is proposed in this study. The system is very simple and can be placed inside a flat piezoelectric micro-stage. The system comprises three two-DOF optical measurement modules, each having a quadrant photo diode (QPD), a lens, and a laser diode. These three modules and the geometric configuration of their installation allow displacement measurements with up to six-DOF to be made. A mathematical model of this system is also presented. By analyzing the sensitivity and relationship between the displacement of the stage and each of the QPD light spots, movement can be observed. Signal feedback enables multi-axis nano-scale positioning control. We also present a new six-DOF nano stage, which uses piezoelectric actuators for displacement. This stage was used to verify the proposed six-DOF measurement system. Linear and angular resolution of the system can be down to 10 nm and 0.1 arcsec. Linear and angular displacement measurement errors of this six-DOF measurement system are in the range of ±70 nm and ±0.65 arcsec.
authors.affiliation: Graduate Institute of Electro-Optical and Materials Science, National Formosa University, Yunlin 632, Taiwan.
authors.forename: Guo-Yuan
authors.initials: GY
authors.lastname: Zhuang
authors.affiliation: Center for Measurement Standards, Industrial Technology Research Institute, Hsinchu 300, Taiwan.
authors.forename: Hau-Wei
authors.initials: HW
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, National Chung-Hsing University, Taichung 402, Taiwan.
authors.forename: Chien-Hung
authors.initials: CH
authors.lastname: Liu