Acoustic micropump device using piezoelectric transducers to create a directional fluid flow

Abstract

The present disclosure relates to a micropump device for creating a net fluid flow along a flow direction. The device includes a fluid channel and a plurality of piezoelectric transducers arranged adjacent to the fluid channel. The piezoelectric transducers are organized into a set of at least three groups. The groups are consecutively arranged along the flow direction, and each group includes at least one piezoelectric transducer. A controller of the device is configured to actuate the piezoelectric transducers using at least three periodic electrical control signals. Each electrical control signal is associated with one group of the set. The controller is configured to consecutively delay the at least three electrical control signals, in accordance with the consecutively arranged groups of the set, to create the net flow of fluid along the flow direction.

What is claimed is: 
     
         1 . An acoustic micropump device for creating a net flow of fluid along a flow direction, the acoustic micropump device comprising:
 a fluid channel for the fluid;   a plurality of piezoelectric transducers arranged adjacent to the fluid channel,   wherein the piezoelectric transducers are organized into a set comprising at least three groups, the groups consecutively arranged along the flow direction, and each group comprising at least one piezoelectric transducer,   wherein each piezoelectric transducer of the plurality of piezoelectric transducers comprises a respective membrane, which is configured to vibrate when the piezoelectric transducer is electrically actuated and configured to acoustically couple to the fluid channel; and   a controller configured to actuate the plurality of piezoelectric transducers using at least three periodic electrical control signals, each electrical control signal associated with a group of the at least three groups of the set;   wherein the controller is configured to consecutively delay the at least three electrical control signals, in accordance with the consecutively arranged groups of the set associated with the electrical control signals, to create the net flow of fluid along the flow direction.   
     
     
         2 . The acoustic micropump device according to  claim 1 ,
 wherein the piezoelectric transducers are organized into two or more sets, the two or more sets consecutively arranged along the flow direction;   wherein each set comprises at least three groups of piezoelectric transducers, which are consecutively arranged along the flow direction; and   wherein the controller is configured to actuate the piezoelectric transducers of each set using the at least three electrical control signals, each electrical control signal associated with one group of the set, to create the net flow of fluid along the flow direction.   
     
     
         3 . The acoustic micropump device according to  claim 1 ,
 wherein the at least three groups of the set comprise a first group, a second group, and a third group, which are arranged in this order along the flow direction, and   wherein the at least three electrical control signals are phase-shifted versions of a periodic electrical control signal, wherein the at least three electrical control signals are phase-shifted in accordance with the consecutively arranged groups of the set associated with the at least three electrical control signals and comprise:   a first periodic electrical control signal having a phase shift in a range of −120° to −70°, and associated with the first group;   a second periodic electrical control signal having a phase shift of 0°, and associated with the second group; and   a third periodic electrical control signal having a phase shift in a range of +70° to +120°, and associated with the third group.   
     
     
         4 . The acoustic micropump device according to  claim 1 ,
 wherein the piezoelectric transducers are organized into an array of rows and columns.   
     
     
         5 . The acoustic micropump device according to  claim 4 ,
 wherein each row of piezoelectric transducers is one group of piezoelectric transducers; or   wherein each row of piezoelectric transducers comprises at least three groups of piezoelectric transducers.   
     
     
         6 . The acoustic micropump device according to  claim 1 ,
 wherein the piezoelectric transducers are organized into an array of rows and columns;   wherein the at least one piezoelectric transducer of each group of the at least three groups of the set is arranged in a different row and in a different column than the at least one piezoelectric transducer of the other groups of the at least three groups of the set.   
     
     
         7 . The acoustic micropump device according to  claim 4 ,
 wherein the fluid channel is bonded to the array of piezoelectric transducers.   
     
     
         8 . The acoustic micropump device according to  claim 1 ,
 wherein the respective membrane of each piezoelectric transducer comprises a piezoelectric layer, which is positioned between a bottom electrode and a top electrode of the piezoelectric transducer.   
     
     
         9 . The acoustic micropump device according to  claim 8 ,
 wherein the fluid channel comprises an elastic layer attached to the respective membrane or to the top electrode.   
     
     
         10 . The acoustic micropump device according to  claim 8 ,
 wherein the piezoelectric transducers of the same group have a common piezoelectric layer.   
     
     
         11 . The acoustic micropump device of  claim 8 ,
 wherein the electrical control signals are applied to the top electrodes of the piezoelectric transducers and the bottom electrodes of the piezoelectric transducers are grounded; or   wherein the electrical control signals are applied to the bottom electrodes of the piezoelectric transducers and the top electrodes of the piezoelectric transducers are grounded.   
     
     
         12 . The acoustic micropump device according to  claim 11 ,
 wherein the top electrodes or the bottom electrodes of two or more piezoelectric transducers of the same group are connected to the controller for receiving the same electrical control signal.   
     
     
         13 . The acoustic micropump device of  claim 8 , wherein the electrical control signals are applied to the top electrodes of the piezoelectric transducers. 
     
     
         14 . The acoustic micropump device of  claim 13 , further comprising
 a grounded shielding layer arranged between the top electrodes and the fluid channel.   
     
     
         15 . The acoustic micropump device according to  claim 1 ,
 wherein the respective membrane of each piezoelectric transducer is suspended in a cavity formed in a substrate of the piezoelectric transducer.   
     
     
         16 . The acoustic micropump device according to  claim 15 ,
 wherein the cavity has a width in a range of 10 μm-150 μm.   
     
     
         17 . The acoustic micropump device according to  claim 15 ,
 wherein a spacing between two adjacent piezoelectric transducers is at least 50 μm-200 μm.   
     
     
         18 . A method of operating an acoustic micropump device to create a net flow of fluid along a flow direction, the acoustic micropump device including
 a fluid channel for the fluid,   a plurality of piezoelectric transducers arranged adjacent to the fluid channel,   
       wherein the piezoelectric transducers are organized into a set comprising at least three groups, the groups consecutively arranged along the flow direction, and each group comprising at least one piezoelectric transducer, 
       wherein each piezoelectric transducer of the plurality of piezoelectric transducers comprises a respective membrane, which is configured to vibrate when the piezoelectric transducer is electrically actuated and to acoustically couple to the fluid channel, and 
       a controller configured to create the net flow of fluid along the flow direction, the method comprising:
 actuating the plurality of piezoelectric transducers using at least three periodic electrical control signals, wherein each electrical control signal is used to actuate all piezoelectric transducers of a group of the at least three groups of the set; and 
 consecutively delaying, via the controller, the at least three electrical control signals to another in accordance with the consecutively arranged groups of the set associated with the electrical control signals. 
 
     
     
         19 . The method of  claim 18 , wherein
 the at least three electrical control signals are phase-shifted versions of a periodic electrical control signal:   a first electrical control signal of the at least three electrical control signals has a phase shift in a range of −120° to −70°, and is used to actuate all piezoelectric transducers of a first group of the at least three groups of piezoelectric transducers of the set;   a second electrical control signal of the at least three electrical control signals has a phase shift of 0°, and is used to actuate all piezoelectric transducers of a second group of the at least three groups of piezoelectric transducers of the set; and   a third electrical control signal of the at least three electrical control signals has a phase shift in a range of +70° to +120°, and is used actuate all piezoelectric transducers of a third group of the at least three groups of piezoelectric transducers of the set; and   the first group, the second group, and the third group are arranged in this order along the flow direction.   
     
     
         20 . The method of  claim 19 , wherein
 the first electrical control signal is further used to actuate all piezoelectric transducers of a fourth group of piezoelectric transducers of a further set;   the second electrical control signal is further used to actuate all piezoelectric transducers of a fifth group of piezoelectric transducers of the further set; and   the third electrical control signal is further used actuate all piezoelectric transducers of a sixth group of piezoelectric transducers of the further set,   wherein the fourth group, the fifth group, and the sixth group are arranged in this order along the flow direction after the first group, the second group, and the third group.