Design, fabrication and characterization of piezoelectric micro-cantilever operated in liquid environment for ultrasound energy source applications
ABSTRACT This paper presents a resonant-driving piezoelectric micro-cantilever for application to the ultrasound source, which can
provide sufficient ultrasound energy in liquid environment by actuating maximally at the cantilever’s resonant frequency.
The compact-sized micro-cantilevers were firstly designed to be operated in deionized water solution in this paper with consideration
of its further application to intravascular catheter-delivered transducer-tipped ultrasound thrombolysis devices as the ultrasound
energy source. The micro-cantilever models, which have the target resonant frequencies of ~40kHz in DI water, were designed
on the basis of numerical calculations, finite element method analysis and pre-experiment results based on the measured resonant
frequencies in air, and fully fabricated by micromachining technologies. The resonant frequencies in DI water for each cantilever
model were measured to be 10.94, 23.14, 33.1, and 44.02kHz which are matched excellently with the targeted frequencies of
10, 20, 30 and 40kHz, respectively. In addition, we could experimentally observe that red blood cells aggregated locally
in 5% diluted blood solution were rapidly disaggregated within a few seconds by sufficient ultrasound energy generated by
resonant-actuations of the proposed micro-cantilever.
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ABSTRACT: A bi-membrane structure is the main component of flow regulators for microfluidics with positive gain actuation. This microstructure is composed of two deformable circular membranes with different area tied by a rigid link that makes them move together. A comprehensive analysis of this microstructure is presented in this paper, which also provides an easy and practical design process in microsystems. The study is based on the microstructure behavior in typical microfluidic networks and is presented using dimensionless plots which have been obtained by numerical simulations based on finite element method performed by CoventorWare. The microstructure is defined using four dimensionless numbers for its seven dimensional parameters, and a dimensionless pressure. This fact represents the universal character of the design, dividing it into geometrical and material parts. The dimensionless pressure allows the use of any homogeneous and isotropic material in the design process of the devices. The values obtained from the plots are compared with simulation results using specific materials and dimensions and these comparisons present good agreement. Using the proposed analysis and design process, this sort of microstructures can be used by MEMS designers as standard components in microfluidic devices.Microsystem Technologies 06/2012; 18. DOI:10.1007/s00542-012-1628-4 · 0.95 Impact Factor