A pressure-balanced electrostatically-actuated microvalve

A new microvalve structure designed to enhance the limited actuation forces available in microfabricated devices by using a pressure-balancing scheme is reported. The concept is to allow the fluid to provide a balancing force on the moving part of the device, thereby reducing the force required to open the valve. Various methods can be used to actuate the valve, but electrostatic actuation is chosen since it is readily integrated with the valve fabrication sequence. The process for implementing the valve concept uses multiple wafer bonding steps (three in the present prototype) and has yielded valves which have been successfully actuated in air using voltages below 350 V.<
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