Liquid Needle

Author

Yu, Hongyu ; Zou, Qiang ; Kwon, Jae Wan ; Huang, Dai ; Kim, Eun Sok

Author_Institution

Dept. of Electr. Eng.-Electrophys., Univ. of Southern California, Los Angeles, CA

Volume

16

Issue

2

fYear

2007

fDate

4/1/2007 12:00:00 AM

Firstpage

445

Lastpage

453

Abstract

This paper describes a novel phenomenon "liquid needle" produced by the self-focusing acoustic transducer (SFAT). The SFAT is composed of a metal/piezo-material/metal plate (with and without a support layer) which has one side air backed while the other side is liquid backed. The SFAT generates and focuses acoustic waves (through wave interference) at the top surface of the liquid (with acoustic intensity up to 15W/cm²). The focused acoustic beam deforms the free liquid surface through the acoustic streaming effect, and produces a needle-shaped liquid column on the free liquid surface. With various SFATs and different types of liquids, we have obtained liquid needles that are 400-12 000 mum tall. The liquid needle diameter at its tip varies from less than 15 mum to more than 200 mum

Keywords

acoustic transducers; bioMEMS; microfluidics; needles; 400 to 12000 micron; FHWB; Fresnel half-wave band; SFAT; acoustic ejector; acoustic streaming; liquid needle; self focusing acoustic wave transducer; Acoustic beams; Acoustic transducers; Acoustic waves; Electrodes; Interference; Lenses; Micromechanical devices; Needles; Piezoelectric transducers; Surface acoustic waves; Acoustic ejector; Fresnel half-wave band (FHWB); acoustic streaming; self- focusing acoustic-wave transducer (SFAT);

fLanguage

English

Journal_Title

Microelectromechanical Systems, Journal of

Publisher

ieee

ISSN

1057-7157

Type

jour

DOI

10.1109/JMEMS.2006.887988

Filename

4147609