Mems-based Self-absorption Micro Pump Developed

As an important component of micro fluidic controlling systems, micropump has many applications, such as biological and chemical analysis, drug delivery, IC chip cooling, and the like. Micropumps have become one hotspot in MEMS research fields. An applicable micropump is fabricated using MEMS technologies in this dissertation.On the basis of analyzing various actuation principles, we decided to use piezoelectric bimorph as the primary actuator of our micropumps. Based on the cantilever model of the piezoelectric bimorph, the deformation formula of the piezoelectric bimorph is obtained. The model of the membranes in micropumps is presented as an elastic lamina with uniform thickness and clamped boundaries. The deformation of the lamina under different loads, such as uniform pressure and concentrated force, at conditions of small deformation and large deformation, are analyzed.Diffuser/nozzle unit can be used as the flow control structure of fluids. On the basis of analyzing the diffuser/nozzle unit, a valve-less micropump is designed and fabricated. The piezoelectric bimorph is used as the actuator, PDMS film is used as the pump membrane, and the cone-shaped aperture fabricated by anisotropic bulk silicon etching is used as the diffuser/nozzle structure. The valve-less micropump works steadily, but cannot fill itself.In order to control the flow direction more effectively, a silicon passive valve is fabricated using double-faced bulk etching technology. Utilizing the passive valve, a passive valve micropump and a hybrid valve micropump are fabricated, both of which can propel liquid steadily, but because of the adhesive clearance between the valve chips, the two micropump cannot self-fill yet, although they have a relatively high compression ratio.SU-8 Photoresist has a lower Young's modulus than silicon, so a SU-8 passive valve can eliminate the influence of the adhesive clearance. It can effectively avoid the reverse leakage, furthermore it has a larger forward flow. An improved micropump is fabricated using the SU-8 valve, the micropump can fill itself and has excellent properties. For water a maximum flow of 3.1mL/min is reached, 29.5mL/min for air, and a maximum output pressure of...