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Patent abstract
A device for controlling the movement of a liquid, comprising: a substrate of material having piezoelectric properties and a system for controlling the movement of a quantity of liquid placed in contact with the substrate; this control system includes at least one interdigitated transducer, applied to the substrate and designed to selectively generate a surface acoustic wave adapted to propagate on the substrate and interact with the quantity of liquid. The control system also includes an acoustic resonator that is in the path of the surface acoustic wave and that is adapted to normally allow forward transmission of the surface acoustic wave with a frequency equal to the resonance frequency of the acoustic resonator medium and to reflect the surface acoustic wave back to the transducer when the amount of liquid is present within the acoustic resonator.