Analysis and experiment of a novel actuating design with a shear mode PZT actuator for microfluidic application

A novel actuating design that uses the shear deformation of a lead zirconate titanate (PZT) actuator to deflect a diaphragm is proposed and applied to the microfluidic system. A silicon chip is micromachined with the feature of a bulge on the diaphragm by an inductive-coupled-plasma deep-reactive-ion etcher (ICP-DRIE). The shear mode actuator glued on the chip surface pushes the bulge and thus deflects the diaphragm. The analytical exact solutions for the deflection and volume displacement of the diaphragm without fluid load are derived by the analysis of the free-body model. The results are compared with the ANSYS numerical solutions and verified by experiments, which reveals acceptable agreement. The experiment employs a two-dimensional laser scanning vibrometer to measure the diaphragm deflection. The application of this design is realized in a diffuser micropump that further functions as a microdroplet ejector with the introduction of a nozzle plate. The ejected droplets of the microejector are observed by a visualization system.