A bi-directional electrostatic microvalve includes a membrane electrode that is controlled by application of voltage to fixed electrodes disposed on either side of the membrane electrode. Dielectric insulating layers separate the electrodes. One of the fixed electrodes defines a microcavity. Microfluidic channels formed into the electrodes provide fluid to the microcavity. A central pad defined in the microcavity places a portion of the second electrode close to the membrane electrode to provide a quick actuation while the microcavity reduces film squeezing pressure of the membrane electrode. In preferred embodiment microvalves, low surface energy and low surface charge trapping coatings, such as fluorocarbon films made from cross-linked carbon di-fluoride monomers or surface monolayers made from fluorocarbon terminated silanol compounds coatings coat the electrode low bulk charge trapping dielectric layers limit charge trapping and other problems and increase device lifetime operation.
|Original language||English (US)|
|U.S. patent number||8628055|
|State||Published - Jan 14 2014|