Piezo tubes, for example, offer radial and axial deflection or, when equipped with segmented electrodes, can be used to provide scanning motion in the XY plane. PI Ceramic can manufacture miniature piezo tubes with standard diameters below 0.8mm and extremely tight tolerances in the 50µm range. Miniature piezo tubes are employed in medical instrumentation, such as endoscopes.
The latest designs are called scanning fiber or scanning catheter endoscopes (SFE) for large-area, full-color imaging with a diameter of only 1mm. These miniature endoscopes enable high-quality, laser-based video images for minimally invasive procedures, but can also open the doors for novel bio-technology applications. The functional principle is based on a segmented miniature tube bonded to a single mode optical fiber running through the tube. The piezo tube is operated in resonant mode and by controlling the phase between the X and Y axes, a spiral scan pattern can be produced.
The application-specific actuator is miniscule, only 4mm long at 0.45mm diameter with very low power requirement for typical operation (5.5mW at 20V operating voltage).