A 3-DOF multi-depth-of-field carrier automatic focusing stage

Automatic focusing Stage is an important part of automatic focusing system, a 3-DOF (z-axis displacement and XY axis tilt) Multi-Depth-Of-Field Carrier Automatic Focusing Stage (CAFS) is designed, manufactured and tested in this paper. The stage is driven by four piezoelectric (PZT) actuators. Based on four bridge amplifying mechanisms, large displacement travel and tilt Angle are obtained. Compared with other focusing stages, the developed stage adopts the focusing mode of directly adjusting the spatial position of the sample to realize focusing, which not only avoids the inherent defects of objective focusing mode, but also has the advantages of compact structure, low shape and overall manufacturing. In this paper, the structural parameters and the overall design of the stage are determined, and then the characteristics of the focusing stage are finite element analyzed. Finally, the performance of the focusing stage is studied experimentally. The maximum Z-axis output displacement of the focusing stage is 213.5 μm, and the maximum X-direction and Y-direction tilt angles are 1.5 and 1.7 mrad, respectively. For the application of CAFS, the practicability of CAFS is verified by Z-axis image superposition acquisition method in automatic focusing system.