A Multi-DOF Cross-Scale Piezoelectric Scanning System for Microscopic Imaging

Abstract

Microscopic imaging across different spatial scales requires a large travel range, high positioning resolution, flexible observation perspectives, and reliable autofocus capability. To address these challenges, this article proposes a multi-degree-of-freedom (DOF) cross-scale piezoelectric scanning system. Unlike conventional hybrid motor-piezoelectric systems suffering from an inherent tradeoff between travel range and positioning resolution, or existing piezoelectric systems limited in travel range and lacking rotational degrees of freedom, our system adopts a unified piezoelectric actuation solution integrating a 4-DOF platform (XY translation and RX-RY rotation) with a compact focusing module (<inline-formula> <tex-math notation="LaTeX">$Z$ </tex-math></inline-formula>-axis focusing). This unified configuration enables large-range scanning, multiangle observation, and precise focusing within a single system. The system achieves a translation range of ±35 mm (12-nm resolution), a rotation range of ±25° (176-nrad resolution), and a focusing range of <inline-formula> <tex-math notation="LaTeX">$359.6~\mu $ </tex-math></inline-formula>m (30-nm resolution), with an autofocus time of 3.36 s and a 94 % success rate. An optical measurement accuracy of <inline-formula> <tex-math notation="LaTeX">$\pm 1~\mu $ </tex-math></inline-formula>m validates its reliability in practical tasks. The system integrates image stitching, <inline-formula> <tex-math notation="LaTeX">$Z$ </tex-math></inline-formula>-axis scanning, perspective rotation, and 3-D reconstruction. Representative experiments in life sciences, materials science, and semiconductor inspection demonstrate its applicability, establishing a versatile solution for advanced microscopic imaging.