Abstract
Self-focused piezoelectric transducers using lead-free (K0.48Na0.48Li0.04)(Nb0.90Sb0.06Ta0.04)O3piezoelectric ceramic have been fabricated for ejecting viscous liquids in the drop-on-demand mode. The lead-free piezoelectric ceramics, with a dense structure and good piezoelectric properties (d33= 230 pC/N and kt= 0.56) are prepared by an ordinary sintering technique, and are used to fabricate the driving and focusing elements (Fresnel zone plates) for the transducers. The Fresnel zone plate is a piezoelectric plate patterned with a series of annular electrodes on its surfaces, and the generated acoustic waves are focused by constructive interference. Our results show that the acoustic waves are effectively self-focused in glycerin (with a viscosity of 1400 mPa s), giving a high pressure at the liquid surface to eject droplets without a nozzle. Driven by a simple wave train comprising a series of sinusoidal voltages with an amplitude of 35 V, a frequency of 4.20 MHz and a duration of 1 ms, the transducer can eject glycerin droplets in the drop-on-demand mode.
Original language | English |
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Pages (from-to) | 168-171 |
Number of pages | 4 |
Journal | Sensors and Actuators, A: Physical |
Volume | 168 |
Issue number | 1 |
DOIs | |
Publication status | Published - 1 Jul 2011 |
Keywords
- Lead-free piezoelectric ceramics
- Liquid ejection
- Self-focused transducer
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Instrumentation
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering