Fluid conveyance device
A fluid conveyance device includes a substrate, and a disk-shaped piezoelectric element arranged in a bendable manner on the substrate. A plurality of substantially circular concentric segment electrodes are provided on the piezoelectric element, and are provided with voltages with phases that are shifted. A wavy ring deformation is thus produced on the piezoelectric element. A pocket produced between the piezoelectric element and the substrate is moved in a radial direction so as to convey a fluid from an outer substantially circular portion to a central portion and to discharge the fluid from the central portion.
1. A fluid conveyance device comprising:
a substrate made of a rigid material; and
a disk-shaped piezoelectric element arranged in a bendable manner on the substrate; wherein
a plurality of substantially circular concentric segment electrodes are provided on the piezoelectric element;
a voltage application device is arranged to apply voltages to the segment electrodes such that the voltages are successively shifted in phase;
the voltages are applied to the segment electrodes with the phases thereof shifted so as to produce a wavy ring deformation on the piezoelectric element and to move a pocket that is produced between the piezoelectric element and the substrate in a radial direction such that a fluid is conveyed between an outer substantially circular portion and a central portion of the substrate;
the disk-shaped piezoelectric element is directly bonded to the substrate along only an outer substantially circular portion of the disk-shaped piezoelectric element;
a first flow passage port is provided on the central portion of one of the substrate and the piezoelectric element;
a second flow passage port is provided on the outer substantially circular portion of one of the substrate and the piezoelectric element or between the outer substantially circular portions of both of the substrate and the piezoelectric element;
the first flow passage port and the second flow passage port are closed by the piezoelectric element and the substrate when no voltages are applied to the piezoelectric element; and
the piezoelectric element and the substrate are in contact with one another at a periphery of the substrate.
2. The fluid conveyance device according to claim 1 , wherein substantially an entire surface of the piezoelectric element is in contact with substantially an entire surface of the substrate when no voltages are applied to the piezoelectric element.
3. The fluid conveyance device according to claim 1 , wherein the piezoelectric element is a multilayer element in which at least three substantially circular concentric segment electrodes and a full-surface nonsegmented electrode are alternately arranged with a piezoelectric layer interposed therebetween.
4. The fluid conveyance device according to claim 1 , wherein
the piezoelectric element is a multilayer element in which a plurality of first substantially circular concentric segment electrodes and a plurality of second segment electrodes are alternately arranged with a piezoelectric layer interposed therebetween; and
the second segment electrodes are substantially concentric with the first segment electrodes and gaps between the second segment electrodes are alternately arranged in the radial direction with a gap between the first segment electrodes.
5. The fluid conveyance device according to claim 1 , wherein
the substrate is defined by another piezoelectric element having a same structure as the piezoelectric element; and
voltages having substantially the same phase are applied to the segment electrodes facing each other on the piezoelectric element and the another piezoelectric element with the phase of the voltage successively shifted so as to symmetrically produce the ring wavy deformation on the piezoelectric element and the another piezoelectric element and move the pocket that is produced between the piezoelectric element and the another piezoelectric element in the radial direction such that the fluid is conveyed.