Abstract
This paper describes a technique to eject liquid droplets in almost any direction with a nozzleless self-focusing acoustic transducer (SFAT) built on a ZnO thin film as well as on a thick PZT substrate. Sectoring of the SFAT annular rings of half-wave-band sources to create a piezoelectrically inactive area causes the droplet ejections to be directed non-perpendicular (i.e., oblique) to the liquid surface. The direction of the droplet ejections depends on the size of the piezoelectrically inactive area within the area of the half-wave-band sources. Droplets are ejected from the center part of the annular rings toward the open inactive area. Various openings up to 90° of pie shape have been made and tested to show that the ejection direction becomes less vertical as the piezoelectrically inactive area in the transducer increases. Additionally, a multi-directional ejector built on ZnO film has been demonstrated to eject micron-sized liquid droplets (several microns in diameter) in any of eight predetermined directions on demand. Larger size liquid droplets (about a hundred microns in diameter) have also been directionally ejected from a sectored SFAT built on a PZT substrate.
Original language | English (US) |
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Article number | 024 |
Pages (from-to) | 2697-2704 |
Number of pages | 8 |
Journal | Journal of Micromechanics and Microengineering |
Volume | 16 |
Issue number | 12 |
DOIs | |
State | Published - Dec 1 2006 |
Externally published | Yes |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Mechanics of Materials
- Mechanical Engineering
- Electrical and Electronic Engineering